Check in the pristine copy of ICU 4.6...

icu46/source/common/ucnv2022.c

+/*
+**********************************************************************
+*   Copyright (C) 2000-2010, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+*   file name:  ucnv2022.c
+*   encoding:   US-ASCII
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 2000feb03
+*   created by: Markus W. Scherer
+*
+*   Change history:
+*
+*   06/29/2000  helena  Major rewrite of the callback APIs.
+*   08/08/2000  Ram     Included support for ISO-2022-JP-2
+*                       Changed implementation of toUnicode
+*                       function
+*   08/21/2000  Ram     Added support for ISO-2022-KR
+*   08/29/2000  Ram     Seperated implementation of EBCDIC to
+*                       ucnvebdc.c
+*   09/20/2000  Ram     Added support for ISO-2022-CN
+*                       Added implementations for getNextUChar()
+*                       for specific 2022 country variants.
+*   10/31/2000  Ram     Implemented offsets logic functions
+*/
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_CONVERSION && !UCONFIG_NO_LEGACY_CONVERSION
+
+#include "unicode/ucnv.h"
+#include "unicode/uset.h"
+#include "unicode/ucnv_err.h"
+#include "unicode/ucnv_cb.h"
+#include "ucnv_imp.h"
+#include "ucnv_bld.h"
+#include "ucnv_cnv.h"
+#include "ucnvmbcs.h"
+#include "cstring.h"
+#include "cmemory.h"
+
+#define LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
+
+#ifdef U_ENABLE_GENERIC_ISO_2022
+/*
+ * I am disabling the generic ISO-2022 converter after proposing to do so on
+ * the icu mailing list two days ago.
+ *
+ * Reasons:
+ * 1. It does not fully support the ISO-2022/ECMA-35 specification with all of
+ *    its designation sequences, single shifts with return to the previous state,
+ *    switch-with-no-return to UTF-16BE or similar, etc.
+ *    This is unlike the language-specific variants like ISO-2022-JP which
+ *    require a much smaller repertoire of ISO-2022 features.
+ *    These variants continue to be supported.
+ * 2. I believe that no one is really using the generic ISO-2022 converter
+ *    but rather always one of the language-specific variants.
+ *    Note that ICU's generic ISO-2022 converter has always output one escape
+ *    sequence followed by UTF-8 for the whole stream.
+ * 3. Switching between subcharsets is extremely slow, because each time
+ *    the previous converter is closed and a new one opened,
+ *    without any kind of caching, least-recently-used list, etc.
+ * 4. The code is currently buggy, and given the above it does not seem
+ *    reasonable to spend the time on maintenance.
+ * 5. ISO-2022 subcharsets should normally be used with 7-bit byte encodings.
+ *    This means, for example, that when ISO-8859-7 is designated, the following
+ *    ISO-2022 bytes 00..7f should be interpreted as ISO-8859-7 bytes 80..ff.
+ *    The ICU ISO-2022 converter does not handle this - and has no information
+ *    about which subconverter would have to be shifted vs. which is designed
+ *    for 7-bit ISO-2022.
+ *
+ * Markus Scherer 2003-dec-03
+ */
+#endif
+
+static const char SHIFT_IN_STR[]  = "\x0F";
+static const char SHIFT_OUT_STR[] = "\x0E";
+
+#define CR      0x0D
+#define LF      0x0A
+#define H_TAB   0x09
+#define V_TAB   0x0B
+#define SPACE   0x20
+
+enum {
+    HWKANA_START=0xff61,
+    HWKANA_END=0xff9f
+};
+
+/*
+ * 94-character sets with native byte values A1..FE are encoded in ISO 2022
+ * as bytes 21..7E. (Subtract 0x80.)
+ * 96-character sets with native byte values A0..FF are encoded in ISO 2022
+ * as bytes 20..7F. (Subtract 0x80.)
+ * Do not encode C1 control codes with native bytes 80..9F
+ * as bytes 00..1F (C0 control codes).
+ */
+enum {
+    GR94_START=0xa1,
+    GR94_END=0xfe,
+    GR96_START=0xa0,
+    GR96_END=0xff
+};
+
+/*
+ * ISO 2022 control codes must not be converted from Unicode
+ * because they would mess up the byte stream.
+ * The bit mask 0x0800c000 has bits set at bit positions 0xe, 0xf, 0x1b
+ * corresponding to SO, SI, and ESC.
+ */
+#define IS_2022_CONTROL(c) (((c)<0x20) && (((uint32_t)1<<(c))&0x0800c000)!=0)
+
+/* for ISO-2022-JP and -CN implementations */
+typedef enum  {
+        /* shared values */
+        INVALID_STATE=-1,
+        ASCII = 0,
+
+        SS2_STATE=0x10,
+        SS3_STATE,
+
+        /* JP */
+        ISO8859_1 = 1 ,
+        ISO8859_7 = 2 ,
+        JISX201  = 3,
+        JISX208 = 4,
+        JISX212 = 5,
+        GB2312  =6,
+        KSC5601 =7,
+        HWKANA_7BIT=8,    /* Halfwidth Katakana 7 bit */
+
+        /* CN */
+        /* the first few enum constants must keep their values because they correspond to myConverterArray[] */
+        GB2312_1=1,
+        ISO_IR_165=2,
+        CNS_11643=3,
+
+        /*
+         * these are used in StateEnum and ISO2022State variables,
+         * but CNS_11643 must be used to index into myConverterArray[]
+         */
+        CNS_11643_0=0x20,
+        CNS_11643_1,
+        CNS_11643_2,
+        CNS_11643_3,
+        CNS_11643_4,
+        CNS_11643_5,
+        CNS_11643_6,
+        CNS_11643_7
+} StateEnum;
+
+/* is the StateEnum charset value for a DBCS charset? */
+#define IS_JP_DBCS(cs) (JISX208<=(cs) && (cs)<=KSC5601)
+
+#define CSM(cs) ((uint16_t)1<<(cs))
+
+/*
+ * Each of these charset masks (with index x) contains a bit for a charset in exact correspondence
+ * to whether that charset is used in the corresponding version x of ISO_2022,locale=ja,version=x
+ *
+ * Note: The converter uses some leniency:
+ * - The escape sequence ESC ( I for half-width 7-bit Katakana is recognized in
+ *   all versions, not just JIS7 and JIS8.
+ * - ICU does not distinguish between different versions of JIS X 0208.
+ */
+enum { MAX_JA_VERSION=4 };
+static const uint16_t jpCharsetMasks[MAX_JA_VERSION+1]={
+    CSM(ASCII)|CSM(JISX201)|CSM(JISX208)|CSM(HWKANA_7BIT),
+    CSM(ASCII)|CSM(JISX201)|CSM(JISX208)|CSM(HWKANA_7BIT)|CSM(JISX212),
+    CSM(ASCII)|CSM(JISX201)|CSM(JISX208)|CSM(HWKANA_7BIT)|CSM(JISX212)|CSM(GB2312)|CSM(KSC5601)|CSM(ISO8859_1)|CSM(ISO8859_7),
+    CSM(ASCII)|CSM(JISX201)|CSM(JISX208)|CSM(HWKANA_7BIT)|CSM(JISX212)|CSM(GB2312)|CSM(KSC5601)|CSM(ISO8859_1)|CSM(ISO8859_7),
+    CSM(ASCII)|CSM(JISX201)|CSM(JISX208)|CSM(HWKANA_7BIT)|CSM(JISX212)|CSM(GB2312)|CSM(KSC5601)|CSM(ISO8859_1)|CSM(ISO8859_7)
+};
+
+typedef enum {
+        ASCII1=0,
+        LATIN1,
+        SBCS,
+        DBCS,
+        MBCS,
+        HWKANA
+}Cnv2022Type;
+
+typedef struct ISO2022State {
+    int8_t cs[4];       /* charset number for SI (G0)/SO (G1)/SS2 (G2)/SS3 (G3) */
+    int8_t g;           /* 0..3 for G0..G3 (SI/SO/SS2/SS3) */
+    int8_t prevG;       /* g before single shift (SS2 or SS3) */
+} ISO2022State;
+
+#define UCNV_OPTIONS_VERSION_MASK 0xf
+#define UCNV_2022_MAX_CONVERTERS 10
+
+typedef struct{
+    UConverterSharedData *myConverterArray[UCNV_2022_MAX_CONVERTERS];
+    UConverter *currentConverter;
+    Cnv2022Type currentType;
+    ISO2022State toU2022State, fromU2022State;
+    uint32_t key;
+    uint32_t version;
+#ifdef U_ENABLE_GENERIC_ISO_2022
+    UBool isFirstBuffer;
+#endif
+    UBool isEmptySegment;
+    char name[30];
+    char locale[3];
+}UConverterDataISO2022;
+
+/* Protos */
+/* ISO-2022 ----------------------------------------------------------------- */
+
+/*Forward declaration */
+U_CFUNC void
+ucnv_fromUnicode_UTF8(UConverterFromUnicodeArgs * args,
+                      UErrorCode * err);
+U_CFUNC void
+ucnv_fromUnicode_UTF8_OFFSETS_LOGIC(UConverterFromUnicodeArgs * args,
+                                    UErrorCode * err);
+
+#define ESC_2022 0x1B /*ESC*/
+
+typedef enum
+{
+        INVALID_2022 = -1, /*Doesn't correspond to a valid iso 2022 escape sequence*/
+        VALID_NON_TERMINAL_2022 = 0, /*so far corresponds to a valid iso 2022 escape sequence*/
+        VALID_TERMINAL_2022 = 1, /*corresponds to a valid iso 2022 escape sequence*/
+        VALID_MAYBE_TERMINAL_2022 = 2 /*so far matches one iso 2022 escape sequence, but by adding more characters might match another escape sequence*/
+} UCNV_TableStates_2022;
+
+/*
+* The way these state transition arrays work is:
+* ex : ESC$B is the sequence for JISX208
+*      a) First Iteration: char is ESC
+*          i) Get the value of ESC from normalize_esq_chars_2022[] with int value of ESC as index
+*             int x = normalize_esq_chars_2022[27] which is equal to 1
+*         ii) Search for this value in escSeqStateTable_Key_2022[]
+*             value of x is stored at escSeqStateTable_Key_2022[0]
+*        iii) Save this index as offset
+*         iv) Get state of this sequence from escSeqStateTable_Value_2022[]
+*             escSeqStateTable_Value_2022[offset], which is VALID_NON_TERMINAL_2022
+*     b) Switch on this state and continue to next char
+*          i) Get the value of $ from normalize_esq_chars_2022[] with int value of $ as index
+*             which is normalize_esq_chars_2022[36] == 4
+*         ii) x is currently 1(from above)
+*               x<<=5 -- x is now 32
+*               x+=normalize_esq_chars_2022[36]
+*               now x is 36
+*        iii) Search for this value in escSeqStateTable_Key_2022[]
+*             value of x is stored at escSeqStateTable_Key_2022[2], so offset is 2
+*         iv) Get state of this sequence from escSeqStateTable_Value_2022[]
+*             escSeqStateTable_Value_2022[offset], which is VALID_NON_TERMINAL_2022
+*     c) Switch on this state and continue to next char
+*        i)  Get the value of B from normalize_esq_chars_2022[] with int value of B as index
+*        ii) x is currently 36 (from above)
+*            x<<=5 -- x is now 1152
+*            x+=normalize_esq_chars_2022[66]
+*            now x is 1161
+*       iii) Search for this value in escSeqStateTable_Key_2022[]
+*            value of x is stored at escSeqStateTable_Key_2022[21], so offset is 21
+*        iv) Get state of this sequence from escSeqStateTable_Value_2022[21]
+*            escSeqStateTable_Value_2022[offset], which is VALID_TERMINAL_2022
+*         v) Get the converter name form escSeqStateTable_Result_2022[21] which is JISX208
+*/
+
+
+/*Below are the 3 arrays depicting a state transition table*/
+static const int8_t normalize_esq_chars_2022[256] = {
+/*       0      1       2       3       4      5       6        7       8       9           */
+
+         0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,1      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,4      ,7      ,29      ,0
+        ,2     ,24     ,26     ,27     ,0      ,3      ,23     ,6      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,5      ,8      ,9      ,10     ,11     ,12
+        ,13    ,14     ,15     ,16     ,17     ,18     ,19     ,20     ,25     ,28
+        ,0     ,0      ,21     ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,22    ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0      ,0
+        ,0     ,0      ,0      ,0      ,0      ,0
+};
+
+#ifdef U_ENABLE_GENERIC_ISO_2022
+/*
+ * When the generic ISO-2022 converter is completely removed, not just disabled
+ * per #ifdef, then the following state table and the associated tables that are
+ * dimensioned with MAX_STATES_2022 should be trimmed.
+ *
+ * Especially, VALID_MAYBE_TERMINAL_2022 will not be used any more, and all of
+ * the associated escape sequences starting with ESC ( B should be removed.
+ * This includes the ones with key values 1097 and all of the ones above 1000000.
+ *
+ * For the latter, the tables can simply be truncated.
+ * For the former, since the tables must be kept parallel, it is probably best
+ * to simply duplicate an adjacent table cell, parallel in all tables.
+ *
+ * It may make sense to restructure the tables, especially by using small search
+ * tables for the variants instead of indexing them parallel to the table here.
+ */
+#endif
+
+#define MAX_STATES_2022 74
+static const int32_t escSeqStateTable_Key_2022[MAX_STATES_2022] = {
+/*   0           1           2           3           4           5           6           7           8           9           */
+
+     1          ,34         ,36         ,39         ,55         ,57         ,60         ,61         ,1093       ,1096
+    ,1097       ,1098       ,1099       ,1100       ,1101       ,1102       ,1103       ,1104       ,1105       ,1106
+    ,1109       ,1154       ,1157       ,1160       ,1161       ,1176       ,1178       ,1179       ,1254       ,1257
+    ,1768       ,1773       ,1957       ,35105      ,36933      ,36936      ,36937      ,36938      ,36939      ,36940
+    ,36942      ,36943      ,36944      ,36945      ,36946      ,36947      ,36948      ,37640      ,37642      ,37644
+    ,37646      ,37711      ,37744      ,37745      ,37746      ,37747      ,37748      ,40133      ,40136      ,40138
+    ,40139      ,40140      ,40141      ,1123363    ,35947624   ,35947625   ,35947626   ,35947627   ,35947629   ,35947630
+    ,35947631   ,35947635   ,35947636   ,35947638
+};
+
+#ifdef U_ENABLE_GENERIC_ISO_2022
+
+static const char* const escSeqStateTable_Result_2022[MAX_STATES_2022] = {
+ /*  0                      1                        2                      3                   4                   5                        6                      7                       8                       9    */
+
+     NULL                   ,NULL                   ,NULL                   ,NULL               ,NULL               ,NULL                   ,NULL                   ,NULL                   ,"latin1"               ,"latin1"
+    ,"latin1"               ,"ibm-865"              ,"ibm-865"              ,"ibm-865"          ,"ibm-865"          ,"ibm-865"              ,"ibm-865"              ,"JISX0201"             ,"JISX0201"             ,"latin1"
+    ,"latin1"               ,NULL                   ,"JISX-208"             ,"ibm-5478"         ,"JISX-208"         ,NULL                   ,NULL                   ,NULL                   ,NULL                   ,"UTF8"
+    ,"ISO-8859-1"           ,"ISO-8859-7"           ,"JIS-X-208"            ,NULL               ,"ibm-955"          ,"ibm-367"              ,"ibm-952"              ,"ibm-949"              ,"JISX-212"             ,"ibm-1383"
+    ,"ibm-952"              ,"ibm-964"              ,"ibm-964"              ,"ibm-964"          ,"ibm-964"          ,"ibm-964"              ,"ibm-964"              ,"ibm-5478"         ,"ibm-949"              ,"ISO-IR-165"
+    ,"CNS-11643-1992,1"     ,"CNS-11643-1992,2"     ,"CNS-11643-1992,3"     ,"CNS-11643-1992,4" ,"CNS-11643-1992,5" ,"CNS-11643-1992,6"     ,"CNS-11643-1992,7"     ,"UTF16_PlatformEndian" ,"UTF16_PlatformEndian" ,"UTF16_PlatformEndian"
+    ,"UTF16_PlatformEndian" ,"UTF16_PlatformEndian" ,"UTF16_PlatformEndian" ,NULL               ,"latin1"           ,"ibm-912"              ,"ibm-913"              ,"ibm-914"              ,"ibm-813"              ,"ibm-1089"
+    ,"ibm-920"              ,"ibm-915"              ,"ibm-915"              ,"latin1"
+};
+
+#endif
+
+static const int8_t escSeqStateTable_Value_2022[MAX_STATES_2022] = {
+/*          0                           1                         2                             3                           4                           5                               6                        7                          8                           9       */
+     VALID_NON_TERMINAL_2022    ,VALID_NON_TERMINAL_2022    ,VALID_NON_TERMINAL_2022    ,VALID_NON_TERMINAL_2022     ,VALID_NON_TERMINAL_2022   ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_NON_TERMINAL_2022    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022
+    ,VALID_MAYBE_TERMINAL_2022  ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022
+    ,VALID_TERMINAL_2022        ,VALID_NON_TERMINAL_2022    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_NON_TERMINAL_2022    ,VALID_NON_TERMINAL_2022    ,VALID_NON_TERMINAL_2022    ,VALID_NON_TERMINAL_2022    ,VALID_TERMINAL_2022
+    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_NON_TERMINAL_2022    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022
+    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022
+    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022
+    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_NON_TERMINAL_2022    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022
+    ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022        ,VALID_TERMINAL_2022
+};
+
+
+/* Type def for refactoring changeState_2022 code*/
+typedef enum{
+#ifdef U_ENABLE_GENERIC_ISO_2022
+    ISO_2022=0,
+#endif
+    ISO_2022_JP=1,
+    ISO_2022_KR=2,
+    ISO_2022_CN=3
+} Variant2022;
+
+/*********** ISO 2022 Converter Protos ***********/
+static void
+_ISO2022Open(UConverter *cnv, UConverterLoadArgs *pArgs, UErrorCode *errorCode);
+
+static void
+ _ISO2022Close(UConverter *converter);
+
+static void
+_ISO2022Reset(UConverter *converter, UConverterResetChoice choice);
+
+static const char*
+_ISO2022getName(const UConverter* cnv);
+
+static void
+_ISO_2022_WriteSub(UConverterFromUnicodeArgs *args, int32_t offsetIndex, UErrorCode *err);
+
+static UConverter *
+_ISO_2022_SafeClone(const UConverter *cnv, void *stackBuffer, int32_t *pBufferSize, UErrorCode *status);
+
+#ifdef U_ENABLE_GENERIC_ISO_2022
+static void
+T_UConverter_toUnicode_ISO_2022_OFFSETS_LOGIC(UConverterToUnicodeArgs* args, UErrorCode* err);
+#endif
+
+/*const UConverterSharedData _ISO2022Data;*/
+static const UConverterSharedData _ISO2022JPData;
+static const UConverterSharedData _ISO2022KRData;
+static const UConverterSharedData _ISO2022CNData;
+
+/*************** Converter implementations ******************/
+
+/* The purpose of this function is to get around gcc compiler warnings. */
+static U_INLINE void
+fromUWriteUInt8(UConverter *cnv,
+                 const char *bytes, int32_t length,
+                 uint8_t **target, const char *targetLimit,
+                 int32_t **offsets,
+                 int32_t sourceIndex,
+                 UErrorCode *pErrorCode)
+{
+    char *targetChars = (char *)*target;
+    ucnv_fromUWriteBytes(cnv, bytes, length, &targetChars, targetLimit,
+                         offsets, sourceIndex, pErrorCode);
+    *target = (uint8_t*)targetChars;
+
+}
+
+static U_INLINE void
+setInitialStateToUnicodeKR(UConverter* converter, UConverterDataISO2022 *myConverterData){
+    if(myConverterData->version == 1) {
+        UConverter *cnv = myConverterData->currentConverter;
+
+        cnv->toUnicodeStatus=0;     /* offset */
+        cnv->mode=0;                /* state */
+        cnv->toULength=0;           /* byteIndex */
+    }
+}
+
+static U_INLINE void
+setInitialStateFromUnicodeKR(UConverter* converter,UConverterDataISO2022 *myConverterData){
+   /* in ISO-2022-KR the designator sequence appears only once
+    * in a file so we append it only once
+    */
+    if( converter->charErrorBufferLength==0){
+
+        converter->charErrorBufferLength = 4;
+        converter->charErrorBuffer[0] = 0x1b;
+        converter->charErrorBuffer[1] = 0x24;
+        converter->charErrorBuffer[2] = 0x29;
+        converter->charErrorBuffer[3] = 0x43;
+    }
+    if(myConverterData->version == 1) {
+        UConverter *cnv = myConverterData->currentConverter;
+
+        cnv->fromUChar32=0;
+        cnv->fromUnicodeStatus=1;   /* prevLength */
+    }
+}
+
+static void
+_ISO2022Open(UConverter *cnv, UConverterLoadArgs *pArgs, UErrorCode *errorCode){
+
+    char myLocale[6]={' ',' ',' ',' ',' ',' '};
+
+    cnv->extraInfo = uprv_malloc (sizeof (UConverterDataISO2022));
+    if(cnv->extraInfo != NULL) {
+        UConverterNamePieces stackPieces;
+        UConverterLoadArgs stackArgs={ (int32_t)sizeof(UConverterLoadArgs) };
+        UConverterDataISO2022 *myConverterData=(UConverterDataISO2022 *) cnv->extraInfo;
+        uint32_t version;
+
+        stackArgs.onlyTestIsLoadable = pArgs->onlyTestIsLoadable;
+
+        uprv_memset(myConverterData, 0, sizeof(UConverterDataISO2022));
+        myConverterData->currentType = ASCII1;
+        cnv->fromUnicodeStatus =FALSE;
+        if(pArgs->locale){
+            uprv_strncpy(myLocale, pArgs->locale, sizeof(myLocale));
+        }
+        version = pArgs->options & UCNV_OPTIONS_VERSION_MASK;
+        myConverterData->version = version;
+        if(myLocale[0]=='j' && (myLocale[1]=='a'|| myLocale[1]=='p') &&
+            (myLocale[2]=='_' || myLocale[2]=='\0'))
+        {
+            size_t len=0;
+            /* open the required converters and cache them */
+            if(version>MAX_JA_VERSION) {
+                /* prevent indexing beyond jpCharsetMasks[] */
+                myConverterData->version = version = 0;
+            }
+            if(jpCharsetMasks[version]&CSM(ISO8859_7)) {
+                myConverterData->myConverterArray[ISO8859_7] =
+                    ucnv_loadSharedData("ISO8859_7", &stackPieces, &stackArgs, errorCode);
+            }
+            myConverterData->myConverterArray[JISX208] =
+                ucnv_loadSharedData("Shift-JIS", &stackPieces, &stackArgs, errorCode);
+            if(jpCharsetMasks[version]&CSM(JISX212)) {
+                myConverterData->myConverterArray[JISX212] =
+                    ucnv_loadSharedData("jisx-212", &stackPieces, &stackArgs, errorCode);
+            }
+            if(jpCharsetMasks[version]&CSM(GB2312)) {
+                myConverterData->myConverterArray[GB2312] =
+                    ucnv_loadSharedData("ibm-5478", &stackPieces, &stackArgs, errorCode);   /* gb_2312_80-1 */
+            }
+            if(jpCharsetMasks[version]&CSM(KSC5601)) {
+                myConverterData->myConverterArray[KSC5601] =
+                    ucnv_loadSharedData("ksc_5601", &stackPieces, &stackArgs, errorCode);
+            }
+
+            /* set the function pointers to appropriate funtions */
+            cnv->sharedData=(UConverterSharedData*)(&_ISO2022JPData);
+            uprv_strcpy(myConverterData->locale,"ja");
+
+            (void)uprv_strcpy(myConverterData->name,"ISO_2022,locale=ja,version=");
+            len = uprv_strlen(myConverterData->name);
+            myConverterData->name[len]=(char)(myConverterData->version+(int)'0');
+            myConverterData->name[len+1]='\0';
+        }
+        else if(myLocale[0]=='k' && (myLocale[1]=='o'|| myLocale[1]=='r') &&
+            (myLocale[2]=='_' || myLocale[2]=='\0'))
+        {
+            const char *cnvName;
+            if(version==1) {
+                cnvName="icu-internal-25546";
+            } else {
+                cnvName="ibm-949";
+                myConverterData->version=version=0;
+            }
+            if(pArgs->onlyTestIsLoadable) {
+                ucnv_canCreateConverter(cnvName, errorCode);  /* errorCode carries result */
+                uprv_free(cnv->extraInfo);
+                cnv->extraInfo=NULL;
+                return;
+            } else {
+                myConverterData->currentConverter=ucnv_open(cnvName, errorCode);
+                if (U_FAILURE(*errorCode)) {
+                    _ISO2022Close(cnv);
+                    return;
+                }
+
+                if(version==1) {
+                    (void)uprv_strcpy(myConverterData->name,"ISO_2022,locale=ko,version=1");
+                    uprv_memcpy(cnv->subChars, myConverterData->currentConverter->subChars, 4);
+                    cnv->subCharLen = myConverterData->currentConverter->subCharLen;
+                }else{
+                    (void)uprv_strcpy(myConverterData->name,"ISO_2022,locale=ko,version=0");
+                }
+
+                /* initialize the state variables */
+                setInitialStateToUnicodeKR(cnv, myConverterData);
+                setInitialStateFromUnicodeKR(cnv, myConverterData);
+
+                /* set the function pointers to appropriate funtions */
+                cnv->sharedData=(UConverterSharedData*)&_ISO2022KRData;
+                uprv_strcpy(myConverterData->locale,"ko");
+            }
+        }
+        else if(((myLocale[0]=='z' && myLocale[1]=='h') || (myLocale[0]=='c'&& myLocale[1]=='n'))&&
+            (myLocale[2]=='_' || myLocale[2]=='\0'))
+        {
+
+            /* open the required converters and cache them */
+            myConverterData->myConverterArray[GB2312_1] =
+                ucnv_loadSharedData("ibm-5478", &stackPieces, &stackArgs, errorCode);
+            if(version==1) {
+                myConverterData->myConverterArray[ISO_IR_165] =
+                    ucnv_loadSharedData("iso-ir-165", &stackPieces, &stackArgs, errorCode);
+            }
+            myConverterData->myConverterArray[CNS_11643] =
+                ucnv_loadSharedData("cns-11643-1992", &stackPieces, &stackArgs, errorCode);
+
+
+            /* set the function pointers to appropriate funtions */
+            cnv->sharedData=(UConverterSharedData*)&_ISO2022CNData;
+            uprv_strcpy(myConverterData->locale,"cn");
+
+            if (version==0){
+                myConverterData->version = 0;
+                (void)uprv_strcpy(myConverterData->name,"ISO_2022,locale=zh,version=0");
+            }else if (version==1){
+                myConverterData->version = 1;
+                (void)uprv_strcpy(myConverterData->name,"ISO_2022,locale=zh,version=1");
+            }else {
+                myConverterData->version = 2;
+                (void)uprv_strcpy(myConverterData->name,"ISO_2022,locale=zh,version=2");
+            }
+        }
+        else{
+#ifdef U_ENABLE_GENERIC_ISO_2022
+            myConverterData->isFirstBuffer = TRUE;
+
+            /* append the UTF-8 escape sequence */
+            cnv->charErrorBufferLength = 3;
+            cnv->charErrorBuffer[0] = 0x1b;
+            cnv->charErrorBuffer[1] = 0x25;
+            cnv->charErrorBuffer[2] = 0x42;
+
+            cnv->sharedData=(UConverterSharedData*)&_ISO2022Data;
+            /* initialize the state variables */
+            uprv_strcpy(myConverterData->name,"ISO_2022");
+#else
+            *errorCode = U_UNSUPPORTED_ERROR;
+            return;
+#endif
+        }
+
+        cnv->maxBytesPerUChar=cnv->sharedData->staticData->maxBytesPerChar;
+
+        if(U_FAILURE(*errorCode) || pArgs->onlyTestIsLoadable) {
+            _ISO2022Close(cnv);
+        }
+    } else {
+        *errorCode = U_MEMORY_ALLOCATION_ERROR;
+    }
+}
+
+
+static void
+_ISO2022Close(UConverter *converter) {
+    UConverterDataISO2022* myData =(UConverterDataISO2022 *) (converter->extraInfo);
+    UConverterSharedData **array = myData->myConverterArray;
+    int32_t i;
+
+    if (converter->extraInfo != NULL) {
+        /*close the array of converter pointers and free the memory*/
+        for (i=0; i<UCNV_2022_MAX_CONVERTERS; i++) {
+            if(array[i]!=NULL) {
+                ucnv_unloadSharedDataIfReady(array[i]);
+            }
+        }
+
+        ucnv_close(myData->currentConverter);
+
+        if(!converter->isExtraLocal){
+            uprv_free (converter->extraInfo);
+            converter->extraInfo = NULL;
+        }
+    }
+}
+
+static void
+_ISO2022Reset(UConverter *converter, UConverterResetChoice choice) {
+    UConverterDataISO2022 *myConverterData=(UConverterDataISO2022 *) (converter->extraInfo);
+    if(choice<=UCNV_RESET_TO_UNICODE) {
+        uprv_memset(&myConverterData->toU2022State, 0, sizeof(ISO2022State));
+        myConverterData->key = 0;
+        myConverterData->isEmptySegment = FALSE;
+    }
+    if(choice!=UCNV_RESET_TO_UNICODE) {
+        uprv_memset(&myConverterData->fromU2022State, 0, sizeof(ISO2022State));
+    }
+#ifdef U_ENABLE_GENERIC_ISO_2022
+    if(myConverterData->locale[0] == 0){
+        if(choice<=UCNV_RESET_TO_UNICODE) {
+            myConverterData->isFirstBuffer = TRUE;
+            myConverterData->key = 0;
+            if (converter->mode == UCNV_SO){
+                ucnv_close (myConverterData->currentConverter);
+                myConverterData->currentConverter=NULL;
+            }
+            converter->mode = UCNV_SI;
+        }
+        if(choice!=UCNV_RESET_TO_UNICODE) {
+            /* re-append UTF-8 escape sequence */
+            converter->charErrorBufferLength = 3;
+            converter->charErrorBuffer[0] = 0x1b;
+            converter->charErrorBuffer[1] = 0x28;
+            converter->charErrorBuffer[2] = 0x42;
+        }
+    }
+    else
+#endif
+    {
+        /* reset the state variables */
+        if(myConverterData->locale[0] == 'k'){
+            if(choice<=UCNV_RESET_TO_UNICODE) {
+                setInitialStateToUnicodeKR(converter, myConverterData);
+            }
+            if(choice!=UCNV_RESET_TO_UNICODE) {
+                setInitialStateFromUnicodeKR(converter, myConverterData);
+            }
+        }
+    }
+}
+
+static const char*
+_ISO2022getName(const UConverter* cnv){
+    if(cnv->extraInfo){
+        UConverterDataISO2022* myData= (UConverterDataISO2022*)cnv->extraInfo;
+        return myData->name;
+    }
+    return NULL;
+}
+
+
+/*************** to unicode *******************/
+/****************************************************************************
+ * Recognized escape sequences are
+ * <ESC>(B  ASCII
+ * <ESC>.A  ISO-8859-1
+ * <ESC>.F  ISO-8859-7
+ * <ESC>(J  JISX-201
+ * <ESC>(I  JISX-201
+ * <ESC>$B  JISX-208
+ * <ESC>$@  JISX-208
+ * <ESC>$(D JISX-212
+ * <ESC>$A  GB2312
+ * <ESC>$(C KSC5601
+ */
+static const int8_t nextStateToUnicodeJP[MAX_STATES_2022]= {
+/*      0                1               2               3               4               5               6               7               8               9    */
+    INVALID_STATE   ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,SS2_STATE      ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,ASCII          ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,JISX201        ,HWKANA_7BIT    ,JISX201        ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,JISX208        ,GB2312         ,JISX208        ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,ISO8859_1      ,ISO8859_7      ,JISX208        ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,KSC5601        ,JISX212        ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+};
+
+/*************** to unicode *******************/
+static const int8_t nextStateToUnicodeCN[MAX_STATES_2022]= {
+/*      0                1               2               3               4               5               6               7               8               9    */
+     INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,SS2_STATE      ,SS3_STATE      ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,GB2312_1       ,INVALID_STATE  ,ISO_IR_165
+    ,CNS_11643_1    ,CNS_11643_2    ,CNS_11643_3    ,CNS_11643_4    ,CNS_11643_5    ,CNS_11643_6    ,CNS_11643_7    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+    ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE  ,INVALID_STATE
+};
+
+
+static UCNV_TableStates_2022
+getKey_2022(char c,int32_t* key,int32_t* offset){
+    int32_t togo;
+    int32_t low = 0;
+    int32_t hi = MAX_STATES_2022;
+    int32_t oldmid=0;
+
+    togo = normalize_esq_chars_2022[(uint8_t)c];
+    if(togo == 0) {
+        /* not a valid character anywhere in an escape sequence */
+        *key = 0;
+        *offset = 0;
+        return INVALID_2022;
+    }
+    togo = (*key << 5) + togo;
+
+    while (hi != low)  /*binary search*/{
+
+        register int32_t mid = (hi+low) >> 1; /*Finds median*/
+
+        if (mid == oldmid)
+            break;
+
+        if (escSeqStateTable_Key_2022[mid] > togo){
+            hi = mid;
+        }
+        else if (escSeqStateTable_Key_2022[mid] < togo){
+            low = mid;
+        }
+        else /*we found it*/{
+            *key = togo;
+            *offset = mid;
+            return (UCNV_TableStates_2022)escSeqStateTable_Value_2022[mid];
+        }
+        oldmid = mid;
+
+    }
+
+    *key = 0;
+    *offset = 0;
+    return INVALID_2022;
+}
+
+/*runs through a state machine to determine the escape sequence - codepage correspondance
+ */
+static void
+changeState_2022(UConverter* _this,
+                const char** source,
+                const char* sourceLimit,
+                Variant2022 var,
+                UErrorCode* err){
+    UCNV_TableStates_2022 value;
+    UConverterDataISO2022* myData2022 = ((UConverterDataISO2022*)_this->extraInfo);
+    uint32_t key = myData2022->key;
+    int32_t offset = 0;
+    int8_t initialToULength = _this->toULength;
+    char c;
+
+    value = VALID_NON_TERMINAL_2022;
+    while (*source < sourceLimit) {
+        c = *(*source)++;
+        _this->toUBytes[_this->toULength++]=(uint8_t)c;
+        value = getKey_2022(c,(int32_t *) &key, &offset);
+
+        switch (value){
+
+        case VALID_NON_TERMINAL_2022 :
+            /* continue with the loop */
+            break;
+
+        case VALID_TERMINAL_2022:
+            key = 0;
+            goto DONE;
+
+        case INVALID_2022:
+            goto DONE;
+
+        case VALID_MAYBE_TERMINAL_2022:
+#ifdef U_ENABLE_GENERIC_ISO_2022
+            /* ESC ( B is ambiguous only for ISO_2022 itself */
+            if(var == ISO_2022) {
+                /* discard toUBytes[] for ESC ( B because this sequence is correct and complete */
+                _this->toULength = 0;
+
+                /* TODO need to indicate that ESC ( B was seen; if failure, then need to replay from source or from MBCS-style replay */
+
+                /* continue with the loop */
+                value = VALID_NON_TERMINAL_2022;
+                break;
+            } else
+#endif
+            {
+                /* not ISO_2022 itself, finish here */
+                value = VALID_TERMINAL_2022;
+                key = 0;
+                goto DONE;
+            }
+        }
+    }
+
+DONE:
+    myData2022->key = key;
+
+    if (value == VALID_NON_TERMINAL_2022) {
+        /* indicate that the escape sequence is incomplete: key!=0 */
+        return;
+    } else if (value == INVALID_2022 ) {
+        *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+    } else /* value == VALID_TERMINAL_2022 */ {
+        switch(var){
+#ifdef U_ENABLE_GENERIC_ISO_2022
+        case ISO_2022:
+        {
+            const char *chosenConverterName = escSeqStateTable_Result_2022[offset];
+            if(chosenConverterName == NULL) {
+                /* SS2 or SS3 */
+                *err = U_UNSUPPORTED_ESCAPE_SEQUENCE;
+                _this->toUCallbackReason = UCNV_UNASSIGNED;
+                return;
+            }
+
+            _this->mode = UCNV_SI;
+            ucnv_close(myData2022->currentConverter);
+            myData2022->currentConverter = myUConverter = ucnv_open(chosenConverterName, err);
+            if(U_SUCCESS(*err)) {
+                myUConverter->fromCharErrorBehaviour = UCNV_TO_U_CALLBACK_STOP;
+                _this->mode = UCNV_SO;
+            }
+            break;
+        }
+#endif
+        case ISO_2022_JP:
+            {
+                StateEnum tempState=(StateEnum)nextStateToUnicodeJP[offset];
+                switch(tempState) {
+                case INVALID_STATE:
+                    *err = U_UNSUPPORTED_ESCAPE_SEQUENCE;
+                    break;
+                case SS2_STATE:
+                    if(myData2022->toU2022State.cs[2]!=0) {
+                        if(myData2022->toU2022State.g<2) {
+                            myData2022->toU2022State.prevG=myData2022->toU2022State.g;
+                        }
+                        myData2022->toU2022State.g=2;
+                    } else {
+                        /* illegal to have SS2 before a matching designator */
+                        *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+                    }
+                    break;
+                /* case SS3_STATE: not used in ISO-2022-JP-x */
+                case ISO8859_1:
+                case ISO8859_7:
+                    if((jpCharsetMasks[myData2022->version] & CSM(tempState)) == 0) {
+                        *err = U_UNSUPPORTED_ESCAPE_SEQUENCE;
+                    } else {
+                        /* G2 charset for SS2 */
+                        myData2022->toU2022State.cs[2]=(int8_t)tempState;
+                    }
+                    break;
+                default:
+                    if((jpCharsetMasks[myData2022->version] & CSM(tempState)) == 0) {
+                        *err = U_UNSUPPORTED_ESCAPE_SEQUENCE;
+                    } else {
+                        /* G0 charset */
+                        myData2022->toU2022State.cs[0]=(int8_t)tempState;
+                    }
+                    break;
+                }
+            }
+            break;
+        case ISO_2022_CN:
+            {
+                StateEnum tempState=(StateEnum)nextStateToUnicodeCN[offset];
+                switch(tempState) {
+                case INVALID_STATE:
+                    *err = U_UNSUPPORTED_ESCAPE_SEQUENCE;
+                    break;
+                case SS2_STATE:
+                    if(myData2022->toU2022State.cs[2]!=0) {
+                        if(myData2022->toU2022State.g<2) {
+                            myData2022->toU2022State.prevG=myData2022->toU2022State.g;
+                        }
+                        myData2022->toU2022State.g=2;
+                    } else {
+                        /* illegal to have SS2 before a matching designator */
+                        *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+                    }
+                    break;
+                case SS3_STATE:
+                    if(myData2022->toU2022State.cs[3]!=0) {
+                        if(myData2022->toU2022State.g<2) {
+                            myData2022->toU2022State.prevG=myData2022->toU2022State.g;
+                        }
+                        myData2022->toU2022State.g=3;
+                    } else {
+                        /* illegal to have SS3 before a matching designator */
+                        *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+                    }
+                    break;
+                case ISO_IR_165:
+                    if(myData2022->version==0) {
+                        *err = U_UNSUPPORTED_ESCAPE_SEQUENCE;
+                        break;
+                    }
+                    /*fall through*/
+                case GB2312_1:
+                    /*fall through*/
+                case CNS_11643_1:
+                    myData2022->toU2022State.cs[1]=(int8_t)tempState;
+                    break;
+                case CNS_11643_2:
+                    myData2022->toU2022State.cs[2]=(int8_t)tempState;
+                    break;
+                default:
+                    /* other CNS 11643 planes */
+                    if(myData2022->version==0) {
+                        *err = U_UNSUPPORTED_ESCAPE_SEQUENCE;
+                    } else {
+                       myData2022->toU2022State.cs[3]=(int8_t)tempState;
+                    }
+                    break;
+                }
+            }
+            break;
+        case ISO_2022_KR:
+            if(offset==0x30){
+                /* nothing to be done, just accept this one escape sequence */
+            } else {
+                *err = U_UNSUPPORTED_ESCAPE_SEQUENCE;
+            }
+            break;
+
+        default:
+            *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+            break;
+        }
+    }
+    if(U_SUCCESS(*err)) {
+        _this->toULength = 0;
+    } else if(*err==U_ILLEGAL_ESCAPE_SEQUENCE) {
+        if(_this->toULength>1) {
+            /*
+             * Ticket 5691: consistent illegal sequences:
+             * - We include at least the first byte (ESC) in the illegal sequence.
+             * - If any of the non-initial bytes could be the start of a character,
+             *   we stop the illegal sequence before the first one of those.
+             *   In escape sequences, all following bytes are "printable", that is,
+             *   unless they are completely illegal (>7f in SBCS, outside 21..7e in DBCS),
+             *   they are valid single/lead bytes.
+             *   For simplicity, we always only report the initial ESC byte as the
+             *   illegal sequence and back out all other bytes we looked at.
+             */
+            /* Back out some bytes. */
+            int8_t backOutDistance=_this->toULength-1;
+            int8_t bytesFromThisBuffer=_this->toULength-initialToULength;
+            if(backOutDistance<=bytesFromThisBuffer) {
+                /* same as initialToULength<=1 */
+                *source-=backOutDistance;
+            } else {
+                /* Back out bytes from the previous buffer: Need to replay them. */
+                _this->preToULength=(int8_t)(bytesFromThisBuffer-backOutDistance);
+                /* same as -(initialToULength-1) */
+                /* preToULength is negative! */
+                uprv_memcpy(_this->preToU, _this->toUBytes+1, -_this->preToULength);
+                *source-=bytesFromThisBuffer;
+            }
+            _this->toULength=1;
+        }
+    } else if(*err==U_UNSUPPORTED_ESCAPE_SEQUENCE) {
+        _this->toUCallbackReason = UCNV_UNASSIGNED;
+    }
+}
+
+/*Checks the characters of the buffer against valid 2022 escape sequences
+*if the match we return a pointer to the initial start of the sequence otherwise
+*we return sourceLimit
+*/
+/*for 2022 looks ahead in the stream
+ *to determine the longest possible convertible
+ *data stream
+ */
+static U_INLINE const char*
+getEndOfBuffer_2022(const char** source,
+                   const char* sourceLimit,
+                   UBool flush){
+
+    const char* mySource = *source;
+
+#ifdef U_ENABLE_GENERIC_ISO_2022
+    if (*source >= sourceLimit)
+        return sourceLimit;
+
+    do{
+
+        if (*mySource == ESC_2022){
+            int8_t i;
+            int32_t key = 0;
+            int32_t offset;
+            UCNV_TableStates_2022 value = VALID_NON_TERMINAL_2022;
+
+            /* Kludge: I could not
+            * figure out the reason for validating an escape sequence
+            * twice - once here and once in changeState_2022().
+            * is it possible to have an ESC character in a ISO2022
+            * byte stream which is valid in a code page? Is it legal?
+            */
+            for (i=0;
+            (mySource+i < sourceLimit)&&(value == VALID_NON_TERMINAL_2022);
+            i++) {
+                value =  getKey_2022(*(mySource+i), &key, &offset);
+            }
+            if (value > 0 || *mySource==ESC_2022)
+                return mySource;
+
+            if ((value == VALID_NON_TERMINAL_2022)&&(!flush) )
+                return sourceLimit;
+        }
+    }while (++mySource < sourceLimit);
+
+    return sourceLimit;
+#else
+    while(mySource < sourceLimit && *mySource != ESC_2022) {
+        ++mySource;
+    }
+    return mySource;
+#endif
+}
+
+
+/* This inline function replicates code in _MBCSFromUChar32() function in ucnvmbcs.c
+ * any future change in _MBCSFromUChar32() function should be reflected here.
+ * @return number of bytes in *value; negative number if fallback; 0 if no mapping
+ */
+static U_INLINE int32_t
+MBCS_FROM_UCHAR32_ISO2022(UConverterSharedData* sharedData,
+                                         UChar32 c,
+                                         uint32_t* value,
+                                         UBool useFallback,
+                                         int outputType)
+{
+    const int32_t *cx;
+    const uint16_t *table;
+    uint32_t stage2Entry;
+    uint32_t myValue;
+    int32_t length;
+    const uint8_t *p;
+    /*
+     * TODO(markus): Use and require new, faster MBCS conversion table structures.
+     * Use internal version of ucnv_open() that verifies that the new structures are available,
+     * else U_INTERNAL_PROGRAM_ERROR.
+     */
+    /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
+    if(c<0x10000 || (sharedData->mbcs.unicodeMask&UCNV_HAS_SUPPLEMENTARY)) {
+        table=sharedData->mbcs.fromUnicodeTable;
+        stage2Entry=MBCS_STAGE_2_FROM_U(table, c);
+        /* get the bytes and the length for the output */
+        if(outputType==MBCS_OUTPUT_2){
+            myValue=MBCS_VALUE_2_FROM_STAGE_2(sharedData->mbcs.fromUnicodeBytes, stage2Entry, c);
+            if(myValue<=0xff) {
+                length=1;
+            } else {
+                length=2;
+            }
+        } else /* outputType==MBCS_OUTPUT_3 */ {
+            p=MBCS_POINTER_3_FROM_STAGE_2(sharedData->mbcs.fromUnicodeBytes, stage2Entry, c);
+            myValue=((uint32_t)*p<<16)|((uint32_t)p[1]<<8)|p[2];
+            if(myValue<=0xff) {
+                length=1;
+            } else if(myValue<=0xffff) {
+                length=2;
+            } else {
+                length=3;
+            }
+        }
+        /* is this code point assigned, or do we use fallbacks? */
+        if((stage2Entry&(1<<(16+(c&0xf))))!=0) {
+            /* assigned */
+            *value=myValue;
+            return length;
+        } else if(FROM_U_USE_FALLBACK(useFallback, c) && myValue!=0) {
+            /*
+             * We allow a 0 byte output if the "assigned" bit is set for this entry.
+             * There is no way with this data structure for fallback output
+             * to be a zero byte.
+             */
+            *value=myValue;
+            return -length;
+        }
+    }
+
+    cx=sharedData->mbcs.extIndexes;
+    if(cx!=NULL) {
+        return ucnv_extSimpleMatchFromU(cx, c, value, useFallback);
+    }
+
+    /* unassigned */
+    return 0;
+}
+
+/* This inline function replicates code in _MBCSSingleFromUChar32() function in ucnvmbcs.c
+ * any future change in _MBCSSingleFromUChar32() function should be reflected here.
+ * @param retval pointer to output byte
+ * @return 1 roundtrip byte  0 no mapping  -1 fallback byte
+ */
+static U_INLINE int32_t
+MBCS_SINGLE_FROM_UCHAR32(UConverterSharedData* sharedData,
+                                       UChar32 c,
+                                       uint32_t* retval,
+                                       UBool useFallback)
+{
+    const uint16_t *table;
+    int32_t value;
+    /* BMP-only codepages are stored without stage 1 entries for supplementary code points */
+    if(c>=0x10000 && !(sharedData->mbcs.unicodeMask&UCNV_HAS_SUPPLEMENTARY)) {
+        return 0;
+    }
+    /* convert the Unicode code point in c into codepage bytes (same as in _MBCSFromUnicodeWithOffsets) */
+    table=sharedData->mbcs.fromUnicodeTable;
+    /* get the byte for the output */
+    value=MBCS_SINGLE_RESULT_FROM_U(table, (uint16_t *)sharedData->mbcs.fromUnicodeBytes, c);
+    /* is this code point assigned, or do we use fallbacks? */
+    *retval=(uint32_t)(value&0xff);
+    if(value>=0xf00) {
+        return 1;  /* roundtrip */
+    } else if(useFallback ? value>=0x800 : value>=0xc00) {
+        return -1;  /* fallback taken */
+    } else {
+        return 0;  /* no mapping */
+    }
+}
+
+/*
+ * Check that the result is a 2-byte value with each byte in the range A1..FE
+ * (strict EUC DBCS) before accepting it and subtracting 0x80 from each byte
+ * to move it to the ISO 2022 range 21..7E.
+ * Return 0 if out of range.
+ */
+static U_INLINE uint32_t
+_2022FromGR94DBCS(uint32_t value) {
+    if( (uint16_t)(value - 0xa1a1) <= (0xfefe - 0xa1a1) &&
+        (uint8_t)(value - 0xa1) <= (0xfe - 0xa1)
+    ) {
+        return value - 0x8080;  /* shift down to 21..7e byte range */
+    } else {
+        return 0;  /* not valid for ISO 2022 */
+    }
+}
+
+#if 0 /* 5691: Call sites now check for validity. They can just += 0x8080 after that. */
+/*
+ * This method does the reverse of _2022FromGR94DBCS(). Given the 2022 code point, it returns the
+ * 2 byte value that is in the range A1..FE for each byte. Otherwise it returns the 2022 code point
+ * unchanged. 
+ */
+static U_INLINE uint32_t
+_2022ToGR94DBCS(uint32_t value) {
+    uint32_t returnValue = value + 0x8080;
+    if( (uint16_t)(returnValue - 0xa1a1) <= (0xfefe - 0xa1a1) &&
+        (uint8_t)(returnValue - 0xa1) <= (0xfe - 0xa1)) {
+        return returnValue;
+    } else {
+        return value;
+    }
+}
+#endif
+
+#ifdef U_ENABLE_GENERIC_ISO_2022
+
+/**********************************************************************************
+*  ISO-2022 Converter
+*
+*
+*/
+
+static void
+T_UConverter_toUnicode_ISO_2022_OFFSETS_LOGIC(UConverterToUnicodeArgs* args,
+                                                           UErrorCode* err){
+    const char* mySourceLimit, *realSourceLimit;
+    const char* sourceStart;
+    const UChar* myTargetStart;
+    UConverter* saveThis;
+    UConverterDataISO2022* myData;
+    int8_t length;
+
+    saveThis = args->converter;
+    myData=((UConverterDataISO2022*)(saveThis->extraInfo));
+
+    realSourceLimit = args->sourceLimit;
+    while (args->source < realSourceLimit) {
+        if(myData->key == 0) { /* are we in the middle of an escape sequence? */
+            /*Find the end of the buffer e.g : Next Escape Seq | end of Buffer*/
+            mySourceLimit = getEndOfBuffer_2022(&(args->source), realSourceLimit, args->flush);
+
+            if(args->source < mySourceLimit) {
+                if(myData->currentConverter==NULL) {
+                    myData->currentConverter = ucnv_open("ASCII",err);
+                    if(U_FAILURE(*err)){
+                        return;
+                    }
+
+                    myData->currentConverter->fromCharErrorBehaviour = UCNV_TO_U_CALLBACK_STOP;
+                    saveThis->mode = UCNV_SO;
+                }
+
+                /* convert to before the ESC or until the end of the buffer */
+                myData->isFirstBuffer=FALSE;
+                sourceStart = args->source;
+                myTargetStart = args->target;
+                args->converter = myData->currentConverter;
+                ucnv_toUnicode(args->converter,
+                    &args->target,
+                    args->targetLimit,
+                    &args->source,
+                    mySourceLimit,
+                    args->offsets,
+                    (UBool)(args->flush && mySourceLimit == realSourceLimit),
+                    err);
+                args->converter = saveThis;
+
+                if (*err == U_BUFFER_OVERFLOW_ERROR) {
+                    /* move the overflow buffer */
+                    length = saveThis->UCharErrorBufferLength = myData->currentConverter->UCharErrorBufferLength;
+                    myData->currentConverter->UCharErrorBufferLength = 0;
+                    if(length > 0) {
+                        uprv_memcpy(saveThis->UCharErrorBuffer,
+                                    myData->currentConverter->UCharErrorBuffer,
+                                    length*U_SIZEOF_UCHAR);
+                    }
+                    return;
+                }
+
+                /*
+                 * At least one of:
+                 * -Error while converting
+                 * -Done with entire buffer
+                 * -Need to write offsets or update the current offset
+                 *  (leave that up to the code in ucnv.c)
+                 *
+                 * or else we just stopped at an ESC byte and continue with changeState_2022()
+                 */
+                if (U_FAILURE(*err) ||
+                    (args->source == realSourceLimit) ||
+                    (args->offsets != NULL && (args->target != myTargetStart || args->source != sourceStart) ||
+                    (mySourceLimit < realSourceLimit && myData->currentConverter->toULength > 0))
+                ) {
+                    /* copy partial or error input for truncated detection and error handling */
+                    if(U_FAILURE(*err)) {
+                        length = saveThis->invalidCharLength = myData->currentConverter->invalidCharLength;
+                        if(length > 0) {
+                            uprv_memcpy(saveThis->invalidCharBuffer, myData->currentConverter->invalidCharBuffer, length);
+                        }
+                    } else {
+                        length = saveThis->toULength = myData->currentConverter->toULength;
+                        if(length > 0) {
+                            uprv_memcpy(saveThis->toUBytes, myData->currentConverter->toUBytes, length);
+                            if(args->source < mySourceLimit) {
+                                *err = U_TRUNCATED_CHAR_FOUND; /* truncated input before ESC */
+                            }
+                        }
+                    }
+                    return;
+                }
+            }
+        }
+
+        sourceStart = args->source;
+        changeState_2022(args->converter,
+               &(args->source),
+               realSourceLimit,
+               ISO_2022,
+               err);
+        if (U_FAILURE(*err) || (args->source != sourceStart && args->offsets != NULL)) {
+            /* let the ucnv.c code update its current offset */
+            return;
+        }
+    }
+}
+
+#endif
+
+/*
+ * To Unicode Callback helper function
+ */
+static void
+toUnicodeCallback(UConverter *cnv,
+                  const uint32_t sourceChar, const uint32_t targetUniChar,
+                  UErrorCode* err){
+    if(sourceChar>0xff){
+        cnv->toUBytes[0] = (uint8_t)(sourceChar>>8);
+        cnv->toUBytes[1] = (uint8_t)sourceChar;
+        cnv->toULength = 2;
+    }
+    else{
+        cnv->toUBytes[0] =(char) sourceChar;
+        cnv->toULength = 1;
+    }
+
+    if(targetUniChar == (missingCharMarker-1/*0xfffe*/)){
+        *err = U_INVALID_CHAR_FOUND;
+    }
+    else{
+        *err = U_ILLEGAL_CHAR_FOUND;
+    }
+}
+
+/**************************************ISO-2022-JP*************************************************/
+
+/************************************** IMPORTANT **************************************************
+* The UConverter_fromUnicode_ISO2022_JP converter does not use ucnv_fromUnicode() functions for SBCS,DBCS and
+* MBCS; instead, the values are obtained directly by calling _MBCSFromUChar32().
+* The converter iterates over each Unicode codepoint
+* to obtain the equivalent codepoints from the codepages supported. Since the source buffer is
+* processed one char at a time it would make sense to reduce the extra processing a canned converter
+* would do as far as possible.
+*
+* If the implementation of these macros or structure of sharedData struct change in the future, make
+* sure that ISO-2022 is also changed.
+***************************************************************************************************
+*/
+
+/***************************************************************************************************
+* Rules for ISO-2022-jp encoding
+* (i)   Escape sequences must be fully contained within a line they should not
+*       span new lines or CRs
+* (ii)  If the last character on a line is represented by two bytes then an ASCII or
+*       JIS-Roman character escape sequence should follow before the line terminates
+* (iii) If the first character on the line is represented by two bytes then a two
+*       byte character escape sequence should precede it
+* (iv)  If no escape sequence is encountered then the characters are ASCII
+* (v)   Latin(ISO-8859-1) and Greek(ISO-8859-7) characters must be designated to G2,
+*       and invoked with SS2 (ESC N).
+* (vi)  If there is any G0 designation in text, there must be a switch to
+*       ASCII or to JIS X 0201-Roman before a space character (but not
+*       necessarily before "ESC 4/14 2/0" or "ESC N ' '") or control
+*       characters such as tab or CRLF.
+* (vi)  Supported encodings:
+*          ASCII, JISX201, JISX208, JISX212, GB2312, KSC5601, ISO-8859-1,ISO-8859-7
+*
+*  source : RFC-1554
+*
+*          JISX201, JISX208,JISX212 : new .cnv data files created
+*          KSC5601 : alias to ibm-949 mapping table
+*          GB2312 : alias to ibm-1386 mapping table
+*          ISO-8859-1 : Algorithmic implemented as LATIN1 case
+*          ISO-8859-7 : alisas to ibm-9409 mapping table
+*/
+
+/* preference order of JP charsets */
+static const StateEnum jpCharsetPref[]={
+    ASCII,
+    JISX201,
+    ISO8859_1,
+    ISO8859_7,
+    JISX208,
+    JISX212,
+    GB2312,
+    KSC5601,
+    HWKANA_7BIT
+};
+
+/*
+ * The escape sequences must be in order of the enum constants like JISX201  = 3,
+ * not in order of jpCharsetPref[]!
+ */
+static const char escSeqChars[][6] ={
+    "\x1B\x28\x42",         /* <ESC>(B  ASCII       */
+    "\x1B\x2E\x41",         /* <ESC>.A  ISO-8859-1  */
+    "\x1B\x2E\x46",         /* <ESC>.F  ISO-8859-7  */
+    "\x1B\x28\x4A",         /* <ESC>(J  JISX-201    */
+    "\x1B\x24\x42",         /* <ESC>$B  JISX-208    */
+    "\x1B\x24\x28\x44",     /* <ESC>$(D JISX-212    */
+    "\x1B\x24\x41",         /* <ESC>$A  GB2312      */
+    "\x1B\x24\x28\x43",     /* <ESC>$(C KSC5601     */
+    "\x1B\x28\x49"          /* <ESC>(I  HWKANA_7BIT */
+
+};
+static  const int8_t escSeqCharsLen[] ={
+    3, /* length of <ESC>(B  ASCII       */
+    3, /* length of <ESC>.A  ISO-8859-1  */
+    3, /* length of <ESC>.F  ISO-8859-7  */
+    3, /* length of <ESC>(J  JISX-201    */
+    3, /* length of <ESC>$B  JISX-208    */
+    4, /* length of <ESC>$(D JISX-212    */
+    3, /* length of <ESC>$A  GB2312      */
+    4, /* length of <ESC>$(C KSC5601     */
+    3  /* length of <ESC>(I  HWKANA_7BIT */
+};
+
+/*
+* The iteration over various code pages works this way:
+* i)   Get the currentState from myConverterData->currentState
+* ii)  Check if the character is mapped to a valid character in the currentState
+*      Yes ->  a) set the initIterState to currentState
+*       b) remain in this state until an invalid character is found
+*      No  ->  a) go to the next code page and find the character
+* iii) Before changing the state increment the current state check if the current state
+*      is equal to the intitIteration state
+*      Yes ->  A character that cannot be represented in any of the supported encodings
+*       break and return a U_INVALID_CHARACTER error
+*      No  ->  Continue and find the character in next code page
+*
+*
+* TODO: Implement a priority technique where the users are allowed to set the priority of code pages
+*/
+
+/* Map 00..7F to Unicode according to JIS X 0201. */
+static U_INLINE uint32_t
+jisx201ToU(uint32_t value) {
+    if(value < 0x5c) {
+        return value;
+    } else if(value == 0x5c) {
+        return 0xa5;
+    } else if(value == 0x7e) {
+        return 0x203e;
+    } else /* value <= 0x7f */ {
+        return value;
+    }
+}
+
+/* Map Unicode to 00..7F according to JIS X 0201. Return U+FFFE if unmappable. */
+static U_INLINE uint32_t
+jisx201FromU(uint32_t value) {
+    if(value<=0x7f) {
+        if(value!=0x5c && value!=0x7e) {
+            return value;
+        }
+    } else if(value==0xa5) {
+        return 0x5c;
+    } else if(value==0x203e) {
+        return 0x7e;
+    }
+    return 0xfffe;
+}
+
+/*
+ * Take a valid Shift-JIS byte pair, check that it is in the range corresponding
+ * to JIS X 0208, and convert it to a pair of 21..7E bytes.
+ * Return 0 if the byte pair is out of range.
+ */
+static U_INLINE uint32_t
+_2022FromSJIS(uint32_t value) {
+    uint8_t trail;
+
+    if(value > 0xEFFC) {
+        return 0;  /* beyond JIS X 0208 */
+    }
+
+    trail = (uint8_t)value;
+
+    value &= 0xff00;  /* lead byte */
+    if(value <= 0x9f00) {
+        value -= 0x7000;
+    } else /* 0xe000 <= value <= 0xef00 */ {
+        value -= 0xb000;
+    }
+    value <<= 1;
+
+    if(trail <= 0x9e) {
+        value -= 0x100;
+        if(trail <= 0x7e) {
+            value |= trail - 0x1f;
+        } else {
+            value |= trail - 0x20;
+        }
+    } else /* trail <= 0xfc */ {
+        value |= trail - 0x7e;
+    }
+    return value;
+}
+
+/*
+ * Convert a pair of JIS X 0208 21..7E bytes to Shift-JIS.
+ * If either byte is outside 21..7E make sure that the result is not valid
+ * for Shift-JIS so that the converter catches it.
+ * Some invalid byte values already turn into equally invalid Shift-JIS
+ * byte values and need not be tested explicitly.
+ */
+static U_INLINE void
+_2022ToSJIS(uint8_t c1, uint8_t c2, char bytes[2]) {
+    if(c1&1) {
+        ++c1;
+        if(c2 <= 0x5f) {
+            c2 += 0x1f;
+        } else if(c2 <= 0x7e) {
+            c2 += 0x20;
+        } else {
+            c2 = 0;  /* invalid */
+        }
+    } else {
+        if((uint8_t)(c2-0x21) <= ((0x7e)-0x21)) {
+            c2 += 0x7e;
+        } else {
+            c2 = 0;  /* invalid */
+        }
+    }
+    c1 >>= 1;
+    if(c1 <= 0x2f) {
+        c1 += 0x70;
+    } else if(c1 <= 0x3f) {
+        c1 += 0xb0;
+    } else {
+        c1 = 0;  /* invalid */
+    }
+    bytes[0] = (char)c1;
+    bytes[1] = (char)c2;
+}
+
+/*
+ * JIS X 0208 has fallbacks from Unicode half-width Katakana to full-width (DBCS)
+ * Katakana.
+ * Now that we use a Shift-JIS table for JIS X 0208 we need to hardcode these fallbacks
+ * because Shift-JIS roundtrips half-width Katakana to single bytes.
+ * These were the only fallbacks in ICU's jisx-208.ucm file.
+ */
+static const uint16_t hwkana_fb[HWKANA_END - HWKANA_START + 1] = {
+    0x2123,  /* U+FF61 */
+    0x2156,
+    0x2157,
+    0x2122,
+    0x2126,
+    0x2572,
+    0x2521,
+    0x2523,
+    0x2525,
+    0x2527,
+    0x2529,
+    0x2563,
+    0x2565,
+    0x2567,
+    0x2543,
+    0x213C,  /* U+FF70 */
+    0x2522,
+    0x2524,
+    0x2526,
+    0x2528,
+    0x252A,
+    0x252B,
+    0x252D,
+    0x252F,
+    0x2531,
+    0x2533,
+    0x2535,
+    0x2537,
+    0x2539,
+    0x253B,
+    0x253D,
+    0x253F,  /* U+FF80 */
+    0x2541,
+    0x2544,
+    0x2546,
+    0x2548,
+    0x254A,
+    0x254B,
+    0x254C,
+    0x254D,
+    0x254E,
+    0x254F,
+    0x2552,
+    0x2555,
+    0x2558,
+    0x255B,
+    0x255E,
+    0x255F,  /* U+FF90 */
+    0x2560,
+    0x2561,
+    0x2562,
+    0x2564,
+    0x2566,
+    0x2568,
+    0x2569,
+    0x256A,
+    0x256B,
+    0x256C,
+    0x256D,
+    0x256F,
+    0x2573,
+    0x212B,
+    0x212C   /* U+FF9F */
+};
+
+static void
+UConverter_fromUnicode_ISO_2022_JP_OFFSETS_LOGIC(UConverterFromUnicodeArgs* args, UErrorCode* err) {
+    UConverter *cnv = args->converter;
+    UConverterDataISO2022 *converterData;
+    ISO2022State *pFromU2022State;
+    uint8_t *target = (uint8_t *) args->target;
+    const uint8_t *targetLimit = (const uint8_t *) args->targetLimit;
+    const UChar* source = args->source;
+    const UChar* sourceLimit = args->sourceLimit;
+    int32_t* offsets = args->offsets;
+    UChar32 sourceChar;
+    char buffer[8];
+    int32_t len, outLen;
+    int8_t choices[10];
+    int32_t choiceCount;
+    uint32_t targetValue = 0;
+    UBool useFallback;
+
+    int32_t i;
+    int8_t cs, g;
+
+    /* set up the state */
+    converterData     = (UConverterDataISO2022*)cnv->extraInfo;
+    pFromU2022State   = &converterData->fromU2022State;
+
+    choiceCount = 0;
+
+    /* check if the last codepoint of previous buffer was a lead surrogate*/
+    if((sourceChar = cnv->fromUChar32)!=0 && target< targetLimit) {
+        goto getTrail;
+    }
+
+    while(source < sourceLimit) {
+        if(target < targetLimit) {
+
+            sourceChar  = *(source++);
+            /*check if the char is a First surrogate*/
+            if(UTF_IS_SURROGATE(sourceChar)) {
+                if(UTF_IS_SURROGATE_FIRST(sourceChar)) {
+getTrail:
+                    /*look ahead to find the trail surrogate*/
+                    if(source < sourceLimit) {
+                        /* test the following code unit */
+                        UChar trail=(UChar) *source;
+                        if(UTF_IS_SECOND_SURROGATE(trail)) {
+                            source++;
+                            sourceChar=UTF16_GET_PAIR_VALUE(sourceChar, trail);
+                            cnv->fromUChar32=0x00;
+                            /* convert this supplementary code point */
+                            /* exit this condition tree */
+                        } else {
+                            /* this is an unmatched lead code unit (1st surrogate) */
+                            /* callback(illegal) */
+                            *err=U_ILLEGAL_CHAR_FOUND;
+                            cnv->fromUChar32=sourceChar;
+                            break;
+                        }
+                    } else {
+                        /* no more input */
+                        cnv->fromUChar32=sourceChar;
+                        break;
+                    }
+                } else {
+                    /* this is an unmatched trail code unit (2nd surrogate) */
+                    /* callback(illegal) */
+                    *err=U_ILLEGAL_CHAR_FOUND;
+                    cnv->fromUChar32=sourceChar;
+                    break;
+                }
+            }
+
+            /* do not convert SO/SI/ESC */
+            if(IS_2022_CONTROL(sourceChar)) {
+                /* callback(illegal) */
+                *err=U_ILLEGAL_CHAR_FOUND;
+                cnv->fromUChar32=sourceChar;
+                break;
+            }
+
+            /* do the conversion */
+
+            if(choiceCount == 0) {
+                uint16_t csm;
+
+                /*
+                 * The csm variable keeps track of which charsets are allowed
+                 * and not used yet while building the choices[].
+                 */
+                csm = jpCharsetMasks[converterData->version];
+                choiceCount = 0;
+
+                /* JIS7/8: try single-byte half-width Katakana before JISX208 */
+                if(converterData->version == 3 || converterData->version == 4) {
+                    choices[choiceCount++] = (int8_t)HWKANA_7BIT;
+                }
+                /* Do not try single-byte half-width Katakana for other versions. */
+                csm &= ~CSM(HWKANA_7BIT);
+
+                /* try the current G0 charset */
+                choices[choiceCount++] = cs = pFromU2022State->cs[0];
+                csm &= ~CSM(cs);
+
+                /* try the current G2 charset */
+                if((cs = pFromU2022State->cs[2]) != 0) {
+                    choices[choiceCount++] = cs;
+                    csm &= ~CSM(cs);
+                }
+
+                /* try all the other possible charsets */
+                for(i = 0; i < LENGTHOF(jpCharsetPref); ++i) {
+                    cs = (int8_t)jpCharsetPref[i];
+                    if(CSM(cs) & csm) {
+                        choices[choiceCount++] = cs;
+                        csm &= ~CSM(cs);
+                    }
+                }
+            }
+
+            cs = g = 0;
+            /*
+             * len==0: no mapping found yet
+             * len<0: found a fallback result: continue looking for a roundtrip but no further fallbacks
+             * len>0: found a roundtrip result, done
+             */
+            len = 0;
+            /*
+             * We will turn off useFallback after finding a fallback,
+             * but we still get fallbacks from PUA code points as usual.
+             * Therefore, we will also need to check that we don't overwrite
+             * an early fallback with a later one.
+             */
+            useFallback = cnv->useFallback;
+
+            for(i = 0; i < choiceCount && len <= 0; ++i) {
+                uint32_t value;
+                int32_t len2;
+                int8_t cs0 = choices[i];
+                switch(cs0) {
+                case ASCII:
+                    if(sourceChar <= 0x7f) {
+                        targetValue = (uint32_t)sourceChar;
+                        len = 1;
+                        cs = cs0;
+                        g = 0;
+                    }
+                    break;
+                case ISO8859_1:
+                    if(GR96_START <= sourceChar && sourceChar <= GR96_END) {
+                        targetValue = (uint32_t)sourceChar - 0x80;
+                        len = 1;
+                        cs = cs0;
+                        g = 2;
+                    }
+                    break;
+                case HWKANA_7BIT:
+                    if((uint32_t)(sourceChar - HWKANA_START) <= (HWKANA_END - HWKANA_START)) {
+                        if(converterData->version==3) {
+                            /* JIS7: use G1 (SO) */
+                            /* Shift U+FF61..U+FF9F to bytes 21..5F. */
+                            targetValue = (uint32_t)(sourceChar - (HWKANA_START - 0x21));
+                            len = 1;
+                            pFromU2022State->cs[1] = cs = cs0; /* do not output an escape sequence */
+                            g = 1;
+                        } else if(converterData->version==4) {
+                            /* JIS8: use 8-bit bytes with any single-byte charset, see escape sequence output below */
+                            /* Shift U+FF61..U+FF9F to bytes A1..DF. */
+                            targetValue = (uint32_t)(sourceChar - (HWKANA_START - 0xa1));
+                            len = 1;
+
+                            cs = pFromU2022State->cs[0];
+                            if(IS_JP_DBCS(cs)) {
+                                /* switch from a DBCS charset to JISX201 */
+                                cs = (int8_t)JISX201;
+                            }
+                            /* else stay in the current G0 charset */
+                            g = 0;
+                        }
+                        /* else do not use HWKANA_7BIT with other versions */
+                    }
+                    break;
+                case JISX201:
+                    /* G0 SBCS */
+                    value = jisx201FromU(sourceChar);
+                    if(value <= 0x7f) {
+                        targetValue = value;
+                        len = 1;
+                        cs = cs0;
+                        g = 0;
+                        useFallback = FALSE;
+                    }
+                    break;
+                case JISX208:
+                    /* G0 DBCS from Shift-JIS table */
+                    len2 = MBCS_FROM_UCHAR32_ISO2022(
+                                converterData->myConverterArray[cs0],
+                                sourceChar, &value,
+                                useFallback, MBCS_OUTPUT_2);
+                    if(len2 == 2 || (len2 == -2 && len == 0)) {  /* only accept DBCS: abs(len)==2 */
+                        value = _2022FromSJIS(value);
+                        if(value != 0) {
+                            targetValue = value;
+                            len = len2;
+                            cs = cs0;
+                            g = 0;
+                            useFallback = FALSE;
+                        }
+                    } else if(len == 0 && useFallback &&
+                              (uint32_t)(sourceChar - HWKANA_START) <= (HWKANA_END - HWKANA_START)) {
+                        targetValue = hwkana_fb[sourceChar - HWKANA_START];
+                        len = -2;
+                        cs = cs0;
+                        g = 0;
+                        useFallback = FALSE;
+                    }
+                    break;
+                case ISO8859_7:
+                    /* G0 SBCS forced to 7-bit output */
+                    len2 = MBCS_SINGLE_FROM_UCHAR32(
+                                converterData->myConverterArray[cs0],
+                                sourceChar, &value,
+                                useFallback);
+                    if(len2 != 0 && !(len2 < 0 && len != 0) && GR96_START <= value && value <= GR96_END) {
+                        targetValue = value - 0x80;
+                        len = len2;
+                        cs = cs0;
+                        g = 2;
+                        useFallback = FALSE;
+                    }
+                    break;
+                default:
+                    /* G0 DBCS */
+                    len2 = MBCS_FROM_UCHAR32_ISO2022(
+                                converterData->myConverterArray[cs0],
+                                sourceChar, &value,
+                                useFallback, MBCS_OUTPUT_2);
+                    if(len2 == 2 || (len2 == -2 && len == 0)) {  /* only accept DBCS: abs(len)==2 */
+                        if(cs0 == KSC5601) {
+                            /*
+                             * Check for valid bytes for the encoding scheme.
+                             * This is necessary because the sub-converter (windows-949)
+                             * has a broader encoding scheme than is valid for 2022.
+                             */
+                            value = _2022FromGR94DBCS(value);
+                            if(value == 0) {
+                                break;
+                            }
+                        }
+                        targetValue = value;
+                        len = len2;
+                        cs = cs0;
+                        g = 0;
+                        useFallback = FALSE;
+                    }
+                    break;
+                }
+            }
+
+            if(len != 0) {
+                if(len < 0) {
+                    len = -len;  /* fallback */
+                }
+                outLen = 0; /* count output bytes */
+
+                /* write SI if necessary (only for JIS7) */
+                if(pFromU2022State->g == 1 && g == 0) {
+                    buffer[outLen++] = UCNV_SI;
+                    pFromU2022State->g = 0;
+                }
+
+                /* write the designation sequence if necessary */
+                if(cs != pFromU2022State->cs[g]) {
+                    int32_t escLen = escSeqCharsLen[cs];
+                    uprv_memcpy(buffer + outLen, escSeqChars[cs], escLen);
+                    outLen += escLen;
+                    pFromU2022State->cs[g] = cs;
+
+                    /* invalidate the choices[] */
+                    choiceCount = 0;
+                }
+
+                /* write the shift sequence if necessary */
+                if(g != pFromU2022State->g) {
+                    switch(g) {
+                    /* case 0 handled before writing escapes */
+                    case 1:
+                        buffer[outLen++] = UCNV_SO;
+                        pFromU2022State->g = 1;
+                        break;
+                    default: /* case 2 */
+                        buffer[outLen++] = 0x1b;
+                        buffer[outLen++] = 0x4e;
+                        break;
+                    /* no case 3: no SS3 in ISO-2022-JP-x */
+                    }
+                }
+
+                /* write the output bytes */
+                if(len == 1) {
+                    buffer[outLen++] = (char)targetValue;
+                } else /* len == 2 */ {
+                    buffer[outLen++] = (char)(targetValue >> 8);
+                    buffer[outLen++] = (char)targetValue;
+                }
+            } else {
+                /*
+                 * if we cannot find the character after checking all codepages
+                 * then this is an error
+                 */
+                *err = U_INVALID_CHAR_FOUND;
+                cnv->fromUChar32=sourceChar;
+                break;
+            }
+
+            if(sourceChar == CR || sourceChar == LF) {
+                /* reset the G2 state at the end of a line (conversion got us into ASCII or JISX201 already) */
+                pFromU2022State->cs[2] = 0;
+                choiceCount = 0;
+            }
+
+            /* output outLen>0 bytes in buffer[] */
+            if(outLen == 1) {
+                *target++ = buffer[0];
+                if(offsets) {
+                    *offsets++ = (int32_t)(source - args->source - 1); /* -1: known to be ASCII */
+                }
+            } else if(outLen == 2 && (target + 2) <= targetLimit) {
+                *target++ = buffer[0];
+                *target++ = buffer[1];
+                if(offsets) {
+                    int32_t sourceIndex = (int32_t)(source - args->source - U16_LENGTH(sourceChar));
+                    *offsets++ = sourceIndex;
+                    *offsets++ = sourceIndex;
+                }
+            } else {
+                fromUWriteUInt8(
+                    cnv,
+                    buffer, outLen,
+                    &target, (const char *)targetLimit,
+                    &offsets, (int32_t)(source - args->source - U16_LENGTH(sourceChar)),
+                    err);
+                if(U_FAILURE(*err)) {
+                    break;
+                }
+            }
+        } /* end if(myTargetIndex<myTargetLength) */
+        else{
+            *err =U_BUFFER_OVERFLOW_ERROR;
+            break;
+        }
+
+    }/* end while(mySourceIndex<mySourceLength) */
+
+    /*
+     * the end of the input stream and detection of truncated input
+     * are handled by the framework, but for ISO-2022-JP conversion
+     * we need to be in ASCII mode at the very end
+     *
+     * conditions:
+     *   successful
+     *   in SO mode or not in ASCII mode
+     *   end of input and no truncated input
+     */
+    if( U_SUCCESS(*err) &&
+        (pFromU2022State->g!=0 || pFromU2022State->cs[0]!=ASCII) &&
+        args->flush && source>=sourceLimit && cnv->fromUChar32==0
+    ) {
+        int32_t sourceIndex;
+
+        outLen = 0;
+
+        if(pFromU2022State->g != 0) {
+            buffer[outLen++] = UCNV_SI;
+            pFromU2022State->g = 0;
+        }
+
+        if(pFromU2022State->cs[0] != ASCII) {
+            int32_t escLen = escSeqCharsLen[ASCII];
+            uprv_memcpy(buffer + outLen, escSeqChars[ASCII], escLen);
+            outLen += escLen;
+            pFromU2022State->cs[0] = (int8_t)ASCII;
+        }
+
+        /* get the source index of the last input character */
+        /*
+         * TODO this would be simpler and more reliable if we used a pair
+         * of sourceIndex/prevSourceIndex like in ucnvmbcs.c
+         * so that we could simply use the prevSourceIndex here;
+         * this code gives an incorrect result for the rare case of an unmatched
+         * trail surrogate that is alone in the last buffer of the text stream
+         */
+        sourceIndex=(int32_t)(source-args->source);
+        if(sourceIndex>0) {
+            --sourceIndex;
+            if( U16_IS_TRAIL(args->source[sourceIndex]) &&
+                (sourceIndex==0 || U16_IS_LEAD(args->source[sourceIndex-1]))
+            ) {
+                --sourceIndex;
+            }
+        } else {
+            sourceIndex=-1;
+        }
+
+        fromUWriteUInt8(
+            cnv,
+            buffer, outLen,
+            &target, (const char *)targetLimit,
+            &offsets, sourceIndex,
+            err);
+    }
+
+    /*save the state and return */
+    args->source = source;
+    args->target = (char*)target;
+}
+
+/*************** to unicode *******************/
+
+static void
+UConverter_toUnicode_ISO_2022_JP_OFFSETS_LOGIC(UConverterToUnicodeArgs *args,
+                                               UErrorCode* err){
+    char tempBuf[2];
+    const char *mySource = (char *) args->source;
+    UChar *myTarget = args->target;
+    const char *mySourceLimit = args->sourceLimit;
+    uint32_t targetUniChar = 0x0000;
+    uint32_t mySourceChar = 0x0000;
+    uint32_t tmpSourceChar = 0x0000;
+    UConverterDataISO2022* myData;
+    ISO2022State *pToU2022State;
+    StateEnum cs;
+
+    myData=(UConverterDataISO2022*)(args->converter->extraInfo);
+    pToU2022State = &myData->toU2022State;
+
+    if(myData->key != 0) {
+        /* continue with a partial escape sequence */
+        goto escape;
+    } else if(args->converter->toULength == 1 && mySource < mySourceLimit && myTarget < args->targetLimit) {
+        /* continue with a partial double-byte character */
+        mySourceChar = args->converter->toUBytes[0];
+        args->converter->toULength = 0;
+        cs = (StateEnum)pToU2022State->cs[pToU2022State->g];
+        targetUniChar = missingCharMarker;
+        goto getTrailByte;
+    }
+
+    while(mySource < mySourceLimit){
+
+        targetUniChar =missingCharMarker;
+
+        if(myTarget < args->targetLimit){
+
+            mySourceChar= (unsigned char) *mySource++;
+
+            switch(mySourceChar) {
+            case UCNV_SI:
+                if(myData->version==3) {
+                    pToU2022State->g=0;
+                    continue;
+                } else {
+                    /* only JIS7 uses SI/SO, not ISO-2022-JP-x */
+                    myData->isEmptySegment = FALSE;     /* reset this, we have a different error */
+                    break;
+                }
+
+            case UCNV_SO:
+                if(myData->version==3) {
+                    /* JIS7: switch to G1 half-width Katakana */
+                    pToU2022State->cs[1] = (int8_t)HWKANA_7BIT;
+                    pToU2022State->g=1;
+                    continue;
+                } else {
+                    /* only JIS7 uses SI/SO, not ISO-2022-JP-x */
+                    myData->isEmptySegment = FALSE;     /* reset this, we have a different error */
+                    break;
+                }
+
+            case ESC_2022:
+                mySource--;
+escape:
+                {
+                    const char * mySourceBefore = mySource;
+                    int8_t toULengthBefore = args->converter->toULength;
+
+                    changeState_2022(args->converter,&(mySource),
+                        mySourceLimit, ISO_2022_JP,err);
+
+                    /* If in ISO-2022-JP only and we successully completed an escape sequence, but previous segment was empty, create an error */
+                    if(myData->version==0 && myData->key==0 && U_SUCCESS(*err) && myData->isEmptySegment) {
+                        *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+                        args->converter->toUCallbackReason = UCNV_IRREGULAR;
+                        args->converter->toULength = (int8_t)(toULengthBefore + (mySource - mySourceBefore));
+                    }
+                }
+
+                /* invalid or illegal escape sequence */
+                if(U_FAILURE(*err)){
+                    args->target = myTarget;
+                    args->source = mySource;
+                    myData->isEmptySegment = FALSE;     /* Reset to avoid future spurious errors */
+                    return;
+                }
+                /* If we successfully completed an escape sequence, we begin a new segment, empty so far */
+                if(myData->key==0) {
+                    myData->isEmptySegment = TRUE;
+                }
+                continue;
+
+            /* ISO-2022-JP does not use single-byte (C1) SS2 and SS3 */
+
+            case CR:
+                /*falls through*/
+            case LF:
+                /* automatically reset to single-byte mode */
+                if((StateEnum)pToU2022State->cs[0] != ASCII && (StateEnum)pToU2022State->cs[0] != JISX201) {
+                    pToU2022State->cs[0] = (int8_t)ASCII;
+                }
+                pToU2022State->cs[2] = 0;
+                pToU2022State->g = 0;
+                /* falls through */
+            default:
+                /* convert one or two bytes */
+                myData->isEmptySegment = FALSE;
+                cs = (StateEnum)pToU2022State->cs[pToU2022State->g];
+                if( (uint8_t)(mySourceChar - 0xa1) <= (0xdf - 0xa1) && myData->version==4 &&
+                    !IS_JP_DBCS(cs)
+                ) {
+                    /* 8-bit halfwidth katakana in any single-byte mode for JIS8 */
+                    targetUniChar = mySourceChar + (HWKANA_START - 0xa1);
+
+                    /* return from a single-shift state to the previous one */
+                    if(pToU2022State->g >= 2) {
+                        pToU2022State->g=pToU2022State->prevG;
+                    }
+                } else switch(cs) {
+                case ASCII:
+                    if(mySourceChar <= 0x7f) {
+                        targetUniChar = mySourceChar;
+                    }
+                    break;
+                case ISO8859_1:
+                    if(mySourceChar <= 0x7f) {
+                        targetUniChar = mySourceChar + 0x80;
+                    }
+                    /* return from a single-shift state to the previous one */
+                    pToU2022State->g=pToU2022State->prevG;
+                    break;
+                case ISO8859_7:
+                    if(mySourceChar <= 0x7f) {
+                        /* convert mySourceChar+0x80 to use a normal 8-bit table */
+                        targetUniChar =
+                            _MBCS_SINGLE_SIMPLE_GET_NEXT_BMP(
+                                myData->myConverterArray[cs],
+                                mySourceChar + 0x80);
+                    }
+                    /* return from a single-shift state to the previous one */
+                    pToU2022State->g=pToU2022State->prevG;
+                    break;
+                case JISX201:
+                    if(mySourceChar <= 0x7f) {
+                        targetUniChar = jisx201ToU(mySourceChar);
+                    }
+                    break;
+                case HWKANA_7BIT:
+                    if((uint8_t)(mySourceChar - 0x21) <= (0x5f - 0x21)) {
+                        /* 7-bit halfwidth Katakana */
+                        targetUniChar = mySourceChar + (HWKANA_START - 0x21);
+                    }
+                    break;
+                default:
+                    /* G0 DBCS */
+                    if(mySource < mySourceLimit) {
+                        int leadIsOk, trailIsOk;
+                        uint8_t trailByte;
+getTrailByte:
+                        trailByte = (uint8_t)*mySource;
+                        /*
+                         * Ticket 5691: consistent illegal sequences:
+                         * - We include at least the first byte in the illegal sequence.
+                         * - If any of the non-initial bytes could be the start of a character,
+                         *   we stop the illegal sequence before the first one of those.
+                         *
+                         * In ISO-2022 DBCS, if the second byte is in the 21..7e range or is
+                         * an ESC/SO/SI, we report only the first byte as the illegal sequence.
+                         * Otherwise we convert or report the pair of bytes.
+                         */
+                        leadIsOk = (uint8_t)(mySourceChar - 0x21) <= (0x7e - 0x21);
+                        trailIsOk = (uint8_t)(trailByte - 0x21) <= (0x7e - 0x21);
+                        if (leadIsOk && trailIsOk) {
+                            ++mySource;
+                            tmpSourceChar = (mySourceChar << 8) | trailByte;
+                            if(cs == JISX208) {
+                                _2022ToSJIS((uint8_t)mySourceChar, trailByte, tempBuf);
+                                mySourceChar = tmpSourceChar;
+                            } else {
+                                /* Copy before we modify tmpSourceChar so toUnicodeCallback() sees the correct bytes. */
+                                mySourceChar = tmpSourceChar;
+                                if (cs == KSC5601) {
+                                    tmpSourceChar += 0x8080;  /* = _2022ToGR94DBCS(tmpSourceChar) */
+                                }
+                                tempBuf[0] = (char)(tmpSourceChar >> 8);
+                                tempBuf[1] = (char)(tmpSourceChar);
+                            }
+                            targetUniChar = ucnv_MBCSSimpleGetNextUChar(myData->myConverterArray[cs], tempBuf, 2, FALSE);
+                        } else if (!(trailIsOk || IS_2022_CONTROL(trailByte))) {
+                            /* report a pair of illegal bytes if the second byte is not a DBCS starter */
+                            ++mySource;
+                            /* add another bit so that the code below writes 2 bytes in case of error */
+                            mySourceChar = 0x10000 | (mySourceChar << 8) | trailByte;
+                        }
+                    } else {
+                        args->converter->toUBytes[0] = (uint8_t)mySourceChar;
+                        args->converter->toULength = 1;
+                        goto endloop;
+                    }
+                }  /* End of inner switch */
+                break;
+            }  /* End of outer switch */
+            if(targetUniChar < (missingCharMarker-1/*0xfffe*/)){
+                if(args->offsets){
+                    args->offsets[myTarget - args->target] = (int32_t)(mySource - args->source - (mySourceChar <= 0xff ? 1 : 2));
+                }
+                *(myTarget++)=(UChar)targetUniChar;
+            }
+            else if(targetUniChar > missingCharMarker){
+                /* disassemble the surrogate pair and write to output*/
+                targetUniChar-=0x0010000;
+                *myTarget = (UChar)(0xd800+(UChar)(targetUniChar>>10));
+                if(args->offsets){
+                    args->offsets[myTarget - args->target] = (int32_t)(mySource - args->source - (mySourceChar <= 0xff ? 1 : 2));
+                }
+                ++myTarget;
+                if(myTarget< args->targetLimit){
+                    *myTarget = (UChar)(0xdc00+(UChar)(targetUniChar&0x3ff));
+                    if(args->offsets){
+                        args->offsets[myTarget - args->target] = (int32_t)(mySource - args->source - (mySourceChar <= 0xff ? 1 : 2));
+                    }
+                    ++myTarget;
+                }else{
+                    args->converter->UCharErrorBuffer[args->converter->UCharErrorBufferLength++]=
+                                    (UChar)(0xdc00+(UChar)(targetUniChar&0x3ff));
+                }
+
+            }
+            else{
+                /* Call the callback function*/
+                toUnicodeCallback(args->converter,mySourceChar,targetUniChar,err);
+                break;
+            }
+        }
+        else{    /* goes with "if(myTarget < args->targetLimit)"  way up near top of function */
+            *err =U_BUFFER_OVERFLOW_ERROR;
+            break;
+        }
+    }
+endloop:
+    args->target = myTarget;
+    args->source = mySource;
+}
+
+
+/***************************************************************
+*   Rules for ISO-2022-KR encoding
+*   i) The KSC5601 designator sequence should appear only once in a file,
+*      at the begining of a line before any KSC5601 characters. This usually
+*      means that it appears by itself on the first line of the file
+*  ii) There are only 2 shifting sequences SO to shift into double byte mode
+*      and SI to shift into single byte mode
+*/
+static void
+UConverter_fromUnicode_ISO_2022_KR_OFFSETS_LOGIC_IBM(UConverterFromUnicodeArgs* args, UErrorCode* err){
+
+    UConverter* saveConv = args->converter;
+    UConverterDataISO2022 *myConverterData=(UConverterDataISO2022*)saveConv->extraInfo;
+    args->converter=myConverterData->currentConverter;
+
+    myConverterData->currentConverter->fromUChar32 = saveConv->fromUChar32;
+    ucnv_MBCSFromUnicodeWithOffsets(args,err);
+    saveConv->fromUChar32 = myConverterData->currentConverter->fromUChar32;
+
+    if(*err == U_BUFFER_OVERFLOW_ERROR) {
+        if(myConverterData->currentConverter->charErrorBufferLength > 0) {
+            uprv_memcpy(
+                saveConv->charErrorBuffer,
+                myConverterData->currentConverter->charErrorBuffer,
+                myConverterData->currentConverter->charErrorBufferLength);
+        }
+        saveConv->charErrorBufferLength = myConverterData->currentConverter->charErrorBufferLength;
+        myConverterData->currentConverter->charErrorBufferLength = 0;
+    }
+    args->converter=saveConv;
+}
+
+static void
+UConverter_fromUnicode_ISO_2022_KR_OFFSETS_LOGIC(UConverterFromUnicodeArgs* args, UErrorCode* err){
+
+    const UChar *source = args->source;
+    const UChar *sourceLimit = args->sourceLimit;
+    unsigned char *target = (unsigned char *) args->target;
+    unsigned char *targetLimit = (unsigned char *) args->targetLimit;
+    int32_t* offsets = args->offsets;
+    uint32_t targetByteUnit = 0x0000;
+    UChar32 sourceChar = 0x0000;
+    UBool isTargetByteDBCS;
+    UBool oldIsTargetByteDBCS;
+    UConverterDataISO2022 *converterData;
+    UConverterSharedData* sharedData;
+    UBool useFallback;
+    int32_t length =0;
+
+    converterData=(UConverterDataISO2022*)args->converter->extraInfo;
+    /* if the version is 1 then the user is requesting
+     * conversion with ibm-25546 pass the arguments to
+     * MBCS converter and return
+     */
+    if(converterData->version==1){
+        UConverter_fromUnicode_ISO_2022_KR_OFFSETS_LOGIC_IBM(args,err);
+        return;
+    }
+
+    /* initialize data */
+    sharedData = converterData->currentConverter->sharedData;
+    useFallback = args->converter->useFallback;
+    isTargetByteDBCS=(UBool)args->converter->fromUnicodeStatus;
+    oldIsTargetByteDBCS = isTargetByteDBCS;
+
+    isTargetByteDBCS   = (UBool) args->converter->fromUnicodeStatus;
+    if((sourceChar = args->converter->fromUChar32)!=0 && target <targetLimit) {
+        goto getTrail;
+    }
+    while(source < sourceLimit){
+
+        targetByteUnit = missingCharMarker;
+
+        if(target < (unsigned char*) args->targetLimit){
+            sourceChar = *source++;
+
+            /* do not convert SO/SI/ESC */
+            if(IS_2022_CONTROL(sourceChar)) {
+                /* callback(illegal) */
+                *err=U_ILLEGAL_CHAR_FOUND;
+                args->converter->fromUChar32=sourceChar;
+                break;
+            }
+
+            length = MBCS_FROM_UCHAR32_ISO2022(sharedData,sourceChar,&targetByteUnit,useFallback,MBCS_OUTPUT_2);
+            if(length < 0) {
+                length = -length;  /* fallback */
+            }
+            /* only DBCS or SBCS characters are expected*/
+            /* DB characters with high bit set to 1 are expected */
+            if( length > 2 || length==0 ||
+                (length == 1 && targetByteUnit > 0x7f) ||
+                (length == 2 &&
+                    ((uint16_t)(targetByteUnit - 0xa1a1) > (0xfefe - 0xa1a1) ||
+                    (uint8_t)(targetByteUnit - 0xa1) > (0xfe - 0xa1)))
+            ) {
+                targetByteUnit=missingCharMarker;
+            }
+            if (targetByteUnit != missingCharMarker){
+
+                oldIsTargetByteDBCS = isTargetByteDBCS;
+                isTargetByteDBCS = (UBool)(targetByteUnit>0x00FF);
+                  /* append the shift sequence */
+                if (oldIsTargetByteDBCS != isTargetByteDBCS ){
+
+                    if (isTargetByteDBCS)
+                        *target++ = UCNV_SO;
+                    else
+                        *target++ = UCNV_SI;
+                    if(offsets)
+                        *(offsets++) = (int32_t)(source - args->source-1);
+                }
+                /* write the targetUniChar  to target */
+                if(targetByteUnit <= 0x00FF){
+                    if( target < targetLimit){
+                        *(target++) = (unsigned char) targetByteUnit;
+                        if(offsets){
+                            *(offsets++) = (int32_t)(source - args->source-1);
+                        }
+
+                    }else{
+                        args->converter->charErrorBuffer[args->converter->charErrorBufferLength++] = (unsigned char) (targetByteUnit);
+                        *err = U_BUFFER_OVERFLOW_ERROR;
+                    }
+                }else{
+                    if(target < targetLimit){
+                        *(target++) =(unsigned char) ((targetByteUnit>>8) -0x80);
+                        if(offsets){
+                            *(offsets++) = (int32_t)(source - args->source-1);
+                        }
+                        if(target < targetLimit){
+                            *(target++) =(unsigned char) (targetByteUnit -0x80);
+                            if(offsets){
+                                *(offsets++) = (int32_t)(source - args->source-1);
+                            }
+                        }else{
+                            args->converter->charErrorBuffer[args->converter->charErrorBufferLength++] = (unsigned char) (targetByteUnit -0x80);
+                            *err = U_BUFFER_OVERFLOW_ERROR;
+                        }
+                    }else{
+                        args->converter->charErrorBuffer[args->converter->charErrorBufferLength++] = (unsigned char) ((targetByteUnit>>8) -0x80);
+                        args->converter->charErrorBuffer[args->converter->charErrorBufferLength++] = (unsigned char) (targetByteUnit-0x80);
+                        *err = U_BUFFER_OVERFLOW_ERROR;
+                    }
+                }
+
+            }
+            else{
+                /* oops.. the code point is unassingned
+                 * set the error and reason
+                 */
+
+                /*check if the char is a First surrogate*/
+                if(UTF_IS_SURROGATE(sourceChar)) {
+                    if(UTF_IS_SURROGATE_FIRST(sourceChar)) {
+getTrail:
+                        /*look ahead to find the trail surrogate*/
+                        if(source <  sourceLimit) {
+                            /* test the following code unit */
+                            UChar trail=(UChar) *source;
+                            if(UTF_IS_SECOND_SURROGATE(trail)) {
+                                source++;
+                                sourceChar=UTF16_GET_PAIR_VALUE(sourceChar, trail);
+                                *err = U_INVALID_CHAR_FOUND;
+                                /* convert this surrogate code point */
+                                /* exit this condition tree */
+                            } else {
+                                /* this is an unmatched lead code unit (1st surrogate) */
+                                /* callback(illegal) */
+                                *err=U_ILLEGAL_CHAR_FOUND;
+                            }
+                        } else {
+                            /* no more input */
+                            *err = U_ZERO_ERROR;
+                        }
+                    } else {
+                        /* this is an unmatched trail code unit (2nd surrogate) */
+                        /* callback(illegal) */
+                        *err=U_ILLEGAL_CHAR_FOUND;
+                    }
+                } else {
+                    /* callback(unassigned) for a BMP code point */
+                    *err = U_INVALID_CHAR_FOUND;
+                }
+
+                args->converter->fromUChar32=sourceChar;
+                break;
+            }
+        } /* end if(myTargetIndex<myTargetLength) */
+        else{
+            *err =U_BUFFER_OVERFLOW_ERROR;
+            break;
+        }
+
+    }/* end while(mySourceIndex<mySourceLength) */
+
+    /*
+     * the end of the input stream and detection of truncated input
+     * are handled by the framework, but for ISO-2022-KR conversion
+     * we need to be in ASCII mode at the very end
+     *
+     * conditions:
+     *   successful
+     *   not in ASCII mode
+     *   end of input and no truncated input
+     */
+    if( U_SUCCESS(*err) &&
+        isTargetByteDBCS &&
+        args->flush && source>=sourceLimit && args->converter->fromUChar32==0
+    ) {
+        int32_t sourceIndex;
+
+        /* we are switching to ASCII */
+        isTargetByteDBCS=FALSE;
+
+        /* get the source index of the last input character */
+        /*
+         * TODO this would be simpler and more reliable if we used a pair
+         * of sourceIndex/prevSourceIndex like in ucnvmbcs.c
+         * so that we could simply use the prevSourceIndex here;
+         * this code gives an incorrect result for the rare case of an unmatched
+         * trail surrogate that is alone in the last buffer of the text stream
+         */
+        sourceIndex=(int32_t)(source-args->source);
+        if(sourceIndex>0) {
+            --sourceIndex;
+            if( U16_IS_TRAIL(args->source[sourceIndex]) &&
+                (sourceIndex==0 || U16_IS_LEAD(args->source[sourceIndex-1]))
+            ) {
+                --sourceIndex;
+            }
+        } else {
+            sourceIndex=-1;
+        }
+
+        fromUWriteUInt8(
+            args->converter,
+            SHIFT_IN_STR, 1,
+            &target, (const char *)targetLimit,
+            &offsets, sourceIndex,
+            err);
+    }
+
+    /*save the state and return */
+    args->source = source;
+    args->target = (char*)target;
+    args->converter->fromUnicodeStatus = (uint32_t)isTargetByteDBCS;
+}
+
+/************************ To Unicode ***************************************/
+
+static void
+UConverter_toUnicode_ISO_2022_KR_OFFSETS_LOGIC_IBM(UConverterToUnicodeArgs *args,
+                                                            UErrorCode* err){
+    char const* sourceStart;
+    UConverterDataISO2022* myData=(UConverterDataISO2022*)(args->converter->extraInfo);
+
+    UConverterToUnicodeArgs subArgs;
+    int32_t minArgsSize;
+
+    /* set up the subconverter arguments */
+    if(args->size<sizeof(UConverterToUnicodeArgs)) {
+        minArgsSize = args->size;
+    } else {
+        minArgsSize = (int32_t)sizeof(UConverterToUnicodeArgs);
+    }
+
+    uprv_memcpy(&subArgs, args, minArgsSize);
+    subArgs.size = (uint16_t)minArgsSize;
+    subArgs.converter = myData->currentConverter;
+
+    /* remember the original start of the input for offsets */
+    sourceStart = args->source;
+
+    if(myData->key != 0) {
+        /* continue with a partial escape sequence */
+        goto escape;
+    }
+
+    while(U_SUCCESS(*err) && args->source < args->sourceLimit) {
+        /*Find the end of the buffer e.g : Next Escape Seq | end of Buffer*/
+        subArgs.source = args->source;
+        subArgs.sourceLimit = getEndOfBuffer_2022(&(args->source), args->sourceLimit, args->flush);
+        if(subArgs.source != subArgs.sourceLimit) {
+            /*
+             * get the current partial byte sequence
+             *
+             * it needs to be moved between the public and the subconverter
+             * so that the conversion framework, which only sees the public
+             * converter, can handle truncated and illegal input etc.
+             */
+            if(args->converter->toULength > 0) {
+                uprv_memcpy(subArgs.converter->toUBytes, args->converter->toUBytes, args->converter->toULength);
+            }
+            subArgs.converter->toULength = args->converter->toULength;
+
+            /*
+             * Convert up to the end of the input, or to before the next escape character.
+             * Does not handle conversion extensions because the preToU[] state etc.
+             * is not copied.
+             */
+            ucnv_MBCSToUnicodeWithOffsets(&subArgs, err);
+
+            if(args->offsets != NULL && sourceStart != args->source) {
+                /* update offsets to base them on the actual start of the input */
+                int32_t *offsets = args->offsets;
+                UChar *target = args->target;
+                int32_t delta = (int32_t)(args->source - sourceStart);
+                while(target < subArgs.target) {
+                    if(*offsets >= 0) {
+                        *offsets += delta;
+                    }
+                    ++offsets;
+                    ++target;
+                }
+            }
+            args->source = subArgs.source;
+            args->target = subArgs.target;
+            args->offsets = subArgs.offsets;
+
+            /* copy input/error/overflow buffers */
+            if(subArgs.converter->toULength > 0) {
+                uprv_memcpy(args->converter->toUBytes, subArgs.converter->toUBytes, subArgs.converter->toULength);
+            }
+            args->converter->toULength = subArgs.converter->toULength;
+
+            if(*err == U_BUFFER_OVERFLOW_ERROR) {
+                if(subArgs.converter->UCharErrorBufferLength > 0) {
+                    uprv_memcpy(args->converter->UCharErrorBuffer, subArgs.converter->UCharErrorBuffer,
+                                subArgs.converter->UCharErrorBufferLength);
+                }
+                args->converter->UCharErrorBufferLength=subArgs.converter->UCharErrorBufferLength;
+                subArgs.converter->UCharErrorBufferLength = 0;
+            }
+        }
+
+        if (U_FAILURE(*err) || (args->source == args->sourceLimit)) {
+            return;
+        }
+
+escape:
+        changeState_2022(args->converter,
+               &(args->source),
+               args->sourceLimit,
+               ISO_2022_KR,
+               err);
+    }
+}
+
+static void
+UConverter_toUnicode_ISO_2022_KR_OFFSETS_LOGIC(UConverterToUnicodeArgs *args,
+                                                            UErrorCode* err){
+    char tempBuf[2];
+    const char *mySource = ( char *) args->source;
+    UChar *myTarget = args->target;
+    const char *mySourceLimit = args->sourceLimit;
+    UChar32 targetUniChar = 0x0000;
+    UChar mySourceChar = 0x0000;
+    UConverterDataISO2022* myData;
+    UConverterSharedData* sharedData ;
+    UBool useFallback;
+
+    myData=(UConverterDataISO2022*)(args->converter->extraInfo);
+    if(myData->version==1){
+        UConverter_toUnicode_ISO_2022_KR_OFFSETS_LOGIC_IBM(args,err);
+        return;
+    }
+
+    /* initialize state */
+    sharedData = myData->currentConverter->sharedData;
+    useFallback = args->converter->useFallback;
+
+    if(myData->key != 0) {
+        /* continue with a partial escape sequence */
+        goto escape;
+    } else if(args->converter->toULength == 1 && mySource < mySourceLimit && myTarget < args->targetLimit) {
+        /* continue with a partial double-byte character */
+        mySourceChar = args->converter->toUBytes[0];
+        args->converter->toULength = 0;
+        goto getTrailByte;
+    }
+
+    while(mySource< mySourceLimit){
+
+        if(myTarget < args->targetLimit){
+
+            mySourceChar= (unsigned char) *mySource++;
+
+            if(mySourceChar==UCNV_SI){
+                myData->toU2022State.g = 0;
+                if (myData->isEmptySegment) {
+                    myData->isEmptySegment = FALSE;     /* we are handling it, reset to avoid future spurious errors */
+                    *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+                    args->converter->toUCallbackReason = UCNV_IRREGULAR;
+                    args->converter->toUBytes[0] = (uint8_t)mySourceChar;
+                    args->converter->toULength = 1;
+                    args->target = myTarget;
+                    args->source = mySource;
+                    return;
+                }
+                /*consume the source */
+                continue;
+            }else if(mySourceChar==UCNV_SO){
+                myData->toU2022State.g = 1;
+                myData->isEmptySegment = TRUE;  /* Begin a new segment, empty so far */
+                /*consume the source */
+                continue;
+            }else if(mySourceChar==ESC_2022){
+                mySource--;
+escape:
+                myData->isEmptySegment = FALSE; /* Any invalid ESC sequences will be detected separately, so just reset this */
+                changeState_2022(args->converter,&(mySource),
+                                mySourceLimit, ISO_2022_KR, err);
+                if(U_FAILURE(*err)){
+                    args->target = myTarget;
+                    args->source = mySource;
+                    return;
+                }
+                continue;
+            }
+
+            myData->isEmptySegment = FALSE;     /* Any invalid char errors will be detected separately, so just reset this */
+            if(myData->toU2022State.g == 1) {
+                if(mySource < mySourceLimit) {
+                    int leadIsOk, trailIsOk;
+                    uint8_t trailByte;
+getTrailByte:
+                    targetUniChar = missingCharMarker;
+                    trailByte = (uint8_t)*mySource;
+                    /*
+                     * Ticket 5691: consistent illegal sequences:
+                     * - We include at least the first byte in the illegal sequence.
+                     * - If any of the non-initial bytes could be the start of a character,
+                     *   we stop the illegal sequence before the first one of those.
+                     *
+                     * In ISO-2022 DBCS, if the second byte is in the 21..7e range or is
+                     * an ESC/SO/SI, we report only the first byte as the illegal sequence.
+                     * Otherwise we convert or report the pair of bytes.
+                     */
+                    leadIsOk = (uint8_t)(mySourceChar - 0x21) <= (0x7e - 0x21);
+                    trailIsOk = (uint8_t)(trailByte - 0x21) <= (0x7e - 0x21);
+                    if (leadIsOk && trailIsOk) {
+                        ++mySource;
+                        tempBuf[0] = (char)(mySourceChar + 0x80);
+                        tempBuf[1] = (char)(trailByte + 0x80);
+                        targetUniChar = ucnv_MBCSSimpleGetNextUChar(sharedData, tempBuf, 2, useFallback);
+                        mySourceChar = (mySourceChar << 8) | trailByte;
+                    } else if (!(trailIsOk || IS_2022_CONTROL(trailByte))) {
+                        /* report a pair of illegal bytes if the second byte is not a DBCS starter */
+                        ++mySource;
+                        /* add another bit so that the code below writes 2 bytes in case of error */
+                        mySourceChar = 0x10000 | (mySourceChar << 8) | trailByte;
+                    }
+                } else {
+                    args->converter->toUBytes[0] = (uint8_t)mySourceChar;
+                    args->converter->toULength = 1;
+                    break;
+                }
+            }
+            else if(mySourceChar <= 0x7f) {
+                targetUniChar = ucnv_MBCSSimpleGetNextUChar(sharedData, mySource - 1, 1, useFallback);
+            } else {
+                targetUniChar = 0xffff;
+            }
+            if(targetUniChar < 0xfffe){
+                if(args->offsets) {
+                    args->offsets[myTarget - args->target] = (int32_t)(mySource - args->source - (mySourceChar <= 0xff ? 1 : 2));
+                }
+                *(myTarget++)=(UChar)targetUniChar;
+            }
+            else {
+                /* Call the callback function*/
+                toUnicodeCallback(args->converter,mySourceChar,targetUniChar,err);
+                break;
+            }
+        }
+        else{
+            *err =U_BUFFER_OVERFLOW_ERROR;
+            break;
+        }
+    }
+    args->target = myTarget;
+    args->source = mySource;
+}
+
+/*************************** END ISO2022-KR *********************************/
+
+/*************************** ISO-2022-CN *********************************
+*
+* Rules for ISO-2022-CN Encoding:
+* i)   The designator sequence must appear once on a line before any instance
+*      of character set it designates.
+* ii)  If two lines contain characters from the same character set, both lines
+*      must include the designator sequence.
+* iii) Once the designator sequence is known, a shifting sequence has to be found
+*      to invoke the  shifting
+* iv)  All lines start in ASCII and end in ASCII.
+* v)   Four shifting sequences are employed for this purpose:
+*
+*      Sequcence   ASCII Eq    Charsets
+*      ----------  -------    ---------
+*      SI           <SI>        US-ASCII
+*      SO           <SO>        CNS-11643-1992 Plane 1, GB2312, ISO-IR-165
+*      SS2          <ESC>N      CNS-11643-1992 Plane 2
+*      SS3          <ESC>O      CNS-11643-1992 Planes 3-7
+*
+* vi)
+*      SOdesignator  : ESC "$" ")" finalchar_for_SO
+*      SS2designator : ESC "$" "*" finalchar_for_SS2
+*      SS3designator : ESC "$" "+" finalchar_for_SS3
+*
+*      ESC $ ) A       Indicates the bytes following SO are Chinese
+*       characters as defined in GB 2312-80, until
+*       another SOdesignation appears
+*
+*
+*      ESC $ ) E       Indicates the bytes following SO are as defined
+*       in ISO-IR-165 (for details, see section 2.1),
+*       until another SOdesignation appears
+*
+*      ESC $ ) G       Indicates the bytes following SO are as defined
+*       in CNS 11643-plane-1, until another
+*       SOdesignation appears
+*
+*      ESC $ * H       Indicates the two bytes immediately following
+*       SS2 is a Chinese character as defined in CNS
+*       11643-plane-2, until another SS2designation
+*       appears
+*       (Meaning <ESC>N must preceed every 2 byte
+*        sequence.)
+*
+*      ESC $ + I       Indicates the immediate two bytes following SS3
+*       is a Chinese character as defined in CNS
+*       11643-plane-3, until another SS3designation
+*       appears
+*       (Meaning <ESC>O must preceed every 2 byte
+*        sequence.)
+*
+*      ESC $ + J       Indicates the immediate two bytes following SS3
+*       is a Chinese character as defined in CNS
+*       11643-plane-4, until another SS3designation
+*       appears
+*       (In English: <ESC>O must preceed every 2 byte
+*        sequence.)
+*
+*      ESC $ + K       Indicates the immediate two bytes following SS3
+*       is a Chinese character as defined in CNS
+*       11643-plane-5, until another SS3designation
+*       appears
+*
+*      ESC $ + L       Indicates the immediate two bytes following SS3
+*       is a Chinese character as defined in CNS
+*       11643-plane-6, until another SS3designation
+*       appears
+*
+*      ESC $ + M       Indicates the immediate two bytes following SS3
+*       is a Chinese character as defined in CNS
+*       11643-plane-7, until another SS3designation
+*       appears
+*
+*       As in ISO-2022-CN, each line starts in ASCII, and ends in ASCII, and
+*       has its own designation information before any Chinese characters
+*       appear
+*
+*/
+
+/* The following are defined this way to make the strings truely readonly */
+static const char GB_2312_80_STR[] = "\x1B\x24\x29\x41";
+static const char ISO_IR_165_STR[] = "\x1B\x24\x29\x45";
+static const char CNS_11643_1992_Plane_1_STR[] = "\x1B\x24\x29\x47";
+static const char CNS_11643_1992_Plane_2_STR[] = "\x1B\x24\x2A\x48";
+static const char CNS_11643_1992_Plane_3_STR[] = "\x1B\x24\x2B\x49";
+static const char CNS_11643_1992_Plane_4_STR[] = "\x1B\x24\x2B\x4A";
+static const char CNS_11643_1992_Plane_5_STR[] = "\x1B\x24\x2B\x4B";
+static const char CNS_11643_1992_Plane_6_STR[] = "\x1B\x24\x2B\x4C";
+static const char CNS_11643_1992_Plane_7_STR[] = "\x1B\x24\x2B\x4D";
+
+/********************** ISO2022-CN Data **************************/
+static const char* const escSeqCharsCN[10] ={
+        SHIFT_IN_STR,           /* ASCII */
+        GB_2312_80_STR,
+        ISO_IR_165_STR,
+        CNS_11643_1992_Plane_1_STR,
+        CNS_11643_1992_Plane_2_STR,
+        CNS_11643_1992_Plane_3_STR,
+        CNS_11643_1992_Plane_4_STR,
+        CNS_11643_1992_Plane_5_STR,
+        CNS_11643_1992_Plane_6_STR,
+        CNS_11643_1992_Plane_7_STR
+};
+
+static void
+UConverter_fromUnicode_ISO_2022_CN_OFFSETS_LOGIC(UConverterFromUnicodeArgs* args, UErrorCode* err){
+    UConverter *cnv = args->converter;
+    UConverterDataISO2022 *converterData;
+    ISO2022State *pFromU2022State;
+    uint8_t *target = (uint8_t *) args->target;
+    const uint8_t *targetLimit = (const uint8_t *) args->targetLimit;
+    const UChar* source = args->source;
+    const UChar* sourceLimit = args->sourceLimit;
+    int32_t* offsets = args->offsets;
+    UChar32 sourceChar;
+    char buffer[8];
+    int32_t len;
+    int8_t choices[3];
+    int32_t choiceCount;
+    uint32_t targetValue = 0;
+    UBool useFallback;
+
+    /* set up the state */
+    converterData     = (UConverterDataISO2022*)cnv->extraInfo;
+    pFromU2022State   = &converterData->fromU2022State;
+
+    choiceCount = 0;
+
+    /* check if the last codepoint of previous buffer was a lead surrogate*/
+    if((sourceChar = cnv->fromUChar32)!=0 && target< targetLimit) {
+        goto getTrail;
+    }
+
+    while( source < sourceLimit){
+        if(target < targetLimit){
+
+            sourceChar  = *(source++);
+            /*check if the char is a First surrogate*/
+             if(UTF_IS_SURROGATE(sourceChar)) {
+                if(UTF_IS_SURROGATE_FIRST(sourceChar)) {
+getTrail:
+                    /*look ahead to find the trail surrogate*/
+                    if(source < sourceLimit) {
+                        /* test the following code unit */
+                        UChar trail=(UChar) *source;
+                        if(UTF_IS_SECOND_SURROGATE(trail)) {
+                            source++;
+                            sourceChar=UTF16_GET_PAIR_VALUE(sourceChar, trail);
+                            cnv->fromUChar32=0x00;
+                            /* convert this supplementary code point */
+                            /* exit this condition tree */
+                        } else {
+                            /* this is an unmatched lead code unit (1st surrogate) */
+                            /* callback(illegal) */
+                            *err=U_ILLEGAL_CHAR_FOUND;
+                            cnv->fromUChar32=sourceChar;
+                            break;
+                        }
+                    } else {
+                        /* no more input */
+                        cnv->fromUChar32=sourceChar;
+                        break;
+                    }
+                } else {
+                    /* this is an unmatched trail code unit (2nd surrogate) */
+                    /* callback(illegal) */
+                    *err=U_ILLEGAL_CHAR_FOUND;
+                    cnv->fromUChar32=sourceChar;
+                    break;
+                }
+            }
+
+            /* do the conversion */
+            if(sourceChar <= 0x007f ){
+                /* do not convert SO/SI/ESC */
+                if(IS_2022_CONTROL(sourceChar)) {
+                    /* callback(illegal) */
+                    *err=U_ILLEGAL_CHAR_FOUND;
+                    cnv->fromUChar32=sourceChar;
+                    break;
+                }
+
+                /* US-ASCII */
+                if(pFromU2022State->g == 0) {
+                    buffer[0] = (char)sourceChar;
+                    len = 1;
+                } else {
+                    buffer[0] = UCNV_SI;
+                    buffer[1] = (char)sourceChar;
+                    len = 2;
+                    pFromU2022State->g = 0;
+                    choiceCount = 0;
+                }
+                if(sourceChar == CR || sourceChar == LF) {
+                    /* reset the state at the end of a line */
+                    uprv_memset(pFromU2022State, 0, sizeof(ISO2022State));
+                    choiceCount = 0;
+                }
+            }
+            else{
+                /* convert U+0080..U+10ffff */
+                int32_t i;
+                int8_t cs, g;
+
+                if(choiceCount == 0) {
+                    /* try the current SO/G1 converter first */
+                    choices[0] = pFromU2022State->cs[1];
+
+                    /* default to GB2312_1 if none is designated yet */
+                    if(choices[0] == 0) {
+                        choices[0] = GB2312_1;
+                    }
+
+                    if(converterData->version == 0) {
+                        /* ISO-2022-CN */
+
+                        /* try the other SO/G1 converter; a CNS_11643_1 lookup may result in any plane */
+                        if(choices[0] == GB2312_1) {
+                            choices[1] = (int8_t)CNS_11643_1;
+                        } else {
+                            choices[1] = (int8_t)GB2312_1;
+                        }
+
+                        choiceCount = 2;
+                    } else if (converterData->version == 1) {
+                        /* ISO-2022-CN-EXT */
+
+                        /* try one of the other converters */
+                        switch(choices[0]) {
+                        case GB2312_1:
+                            choices[1] = (int8_t)CNS_11643_1;
+                            choices[2] = (int8_t)ISO_IR_165;
+                            break;
+                        case ISO_IR_165:
+                            choices[1] = (int8_t)GB2312_1;
+                            choices[2] = (int8_t)CNS_11643_1;
+                            break;
+                        default: /* CNS_11643_x */
+                            choices[1] = (int8_t)GB2312_1;
+                            choices[2] = (int8_t)ISO_IR_165;
+                            break;
+                        }
+
+                        choiceCount = 3;
+                    } else {
+                        choices[0] = (int8_t)CNS_11643_1;
+                        choices[1] = (int8_t)GB2312_1;
+                    }
+                }
+
+                cs = g = 0;
+                /*
+                 * len==0: no mapping found yet
+                 * len<0: found a fallback result: continue looking for a roundtrip but no further fallbacks
+                 * len>0: found a roundtrip result, done
+                 */
+                len = 0;
+                /*
+                 * We will turn off useFallback after finding a fallback,
+                 * but we still get fallbacks from PUA code points as usual.
+                 * Therefore, we will also need to check that we don't overwrite
+                 * an early fallback with a later one.
+                 */
+                useFallback = cnv->useFallback;
+
+                for(i = 0; i < choiceCount && len <= 0; ++i) {
+                    int8_t cs0 = choices[i];
+                    if(cs0 > 0) {
+                        uint32_t value;
+                        int32_t len2;
+                        if(cs0 >= CNS_11643_0) {
+                            len2 = MBCS_FROM_UCHAR32_ISO2022(
+                                        converterData->myConverterArray[CNS_11643],
+                                        sourceChar,
+                                        &value,
+                                        useFallback,
+                                        MBCS_OUTPUT_3);
+                            if(len2 == 3 || (len2 == -3 && len == 0)) {
+                                targetValue = value;
+                                cs = (int8_t)(CNS_11643_0 + (value >> 16) - 0x80);
+                                if(len2 >= 0) {
+                                    len = 2;
+                                } else {
+                                    len = -2;
+                                    useFallback = FALSE;
+                                }
+                                if(cs == CNS_11643_1) {
+                                    g = 1;
+                                } else if(cs == CNS_11643_2) {
+                                    g = 2;
+                                } else /* plane 3..7 */ if(converterData->version == 1) {
+                                    g = 3;
+                                } else {
+                                    /* ISO-2022-CN (without -EXT) does not support plane 3..7 */
+                                    len = 0;
+                                }
+                            }
+                        } else {
+                            /* GB2312_1 or ISO-IR-165 */
+                            len2 = MBCS_FROM_UCHAR32_ISO2022(
+                                        converterData->myConverterArray[cs0],
+                                        sourceChar,
+                                        &value,
+                                        useFallback,
+                                        MBCS_OUTPUT_2);
+                            if(len2 == 2 || (len2 == -2 && len == 0)) {
+                                targetValue = value;
+                                len = len2;
+                                cs = cs0;
+                                g = 1;
+                                useFallback = FALSE;
+                            }
+                        }
+                    }
+                }
+
+                if(len != 0) {
+                    len = 0; /* count output bytes; it must have been abs(len) == 2 */
+
+                    /* write the designation sequence if necessary */
+                    if(cs != pFromU2022State->cs[g]) {
+                        if(cs < CNS_11643) {
+                            uprv_memcpy(buffer, escSeqCharsCN[cs], 4);
+                        } else {
+                            uprv_memcpy(buffer, escSeqCharsCN[CNS_11643 + (cs - CNS_11643_1)], 4);
+                        }
+                        len = 4;
+                        pFromU2022State->cs[g] = cs;
+                        if(g == 1) {
+                            /* changing the SO/G1 charset invalidates the choices[] */
+                            choiceCount = 0;
+                        }
+                    }
+
+                    /* write the shift sequence if necessary */
+                    if(g != pFromU2022State->g) {
+                        switch(g) {
+                        case 1:
+                            buffer[len++] = UCNV_SO;
+
+                            /* set the new state only if it is the locking shift SO/G1, not for SS2 or SS3 */
+                            pFromU2022State->g = 1;
+                            break;
+                        case 2:
+                            buffer[len++] = 0x1b;
+                            buffer[len++] = 0x4e;
+                            break;
+                        default: /* case 3 */
+                            buffer[len++] = 0x1b;
+                            buffer[len++] = 0x4f;
+                            break;
+                        }
+                    }
+
+                    /* write the two output bytes */
+                    buffer[len++] = (char)(targetValue >> 8);
+                    buffer[len++] = (char)targetValue;
+                } else {
+                    /* if we cannot find the character after checking all codepages
+                     * then this is an error
+                     */
+                    *err = U_INVALID_CHAR_FOUND;
+                    cnv->fromUChar32=sourceChar;
+                    break;
+                }
+            }
+
+            /* output len>0 bytes in buffer[] */
+            if(len == 1) {
+                *target++ = buffer[0];
+                if(offsets) {
+                    *offsets++ = (int32_t)(source - args->source - 1); /* -1: known to be ASCII */
+                }
+            } else if(len == 2 && (target + 2) <= targetLimit) {
+                *target++ = buffer[0];
+                *target++ = buffer[1];
+                if(offsets) {
+                    int32_t sourceIndex = (int32_t)(source - args->source - U16_LENGTH(sourceChar));
+                    *offsets++ = sourceIndex;
+                    *offsets++ = sourceIndex;
+                }
+            } else {
+                fromUWriteUInt8(
+                    cnv,
+                    buffer, len,
+                    &target, (const char *)targetLimit,
+                    &offsets, (int32_t)(source - args->source - U16_LENGTH(sourceChar)),
+                    err);
+                if(U_FAILURE(*err)) {
+                    break;
+                }
+            }
+        } /* end if(myTargetIndex<myTargetLength) */
+        else{
+            *err =U_BUFFER_OVERFLOW_ERROR;
+            break;
+        }
+
+    }/* end while(mySourceIndex<mySourceLength) */
+
+    /*
+     * the end of the input stream and detection of truncated input
+     * are handled by the framework, but for ISO-2022-CN conversion
+     * we need to be in ASCII mode at the very end
+     *
+     * conditions:
+     *   successful
+     *   not in ASCII mode
+     *   end of input and no truncated input
+     */
+    if( U_SUCCESS(*err) &&
+        pFromU2022State->g!=0 &&
+        args->flush && source>=sourceLimit && cnv->fromUChar32==0
+    ) {
+        int32_t sourceIndex;
+
+        /* we are switching to ASCII */
+        pFromU2022State->g=0;
+
+        /* get the source index of the last input character */
+        /*
+         * TODO this would be simpler and more reliable if we used a pair
+         * of sourceIndex/prevSourceIndex like in ucnvmbcs.c
+         * so that we could simply use the prevSourceIndex here;
+         * this code gives an incorrect result for the rare case of an unmatched
+         * trail surrogate that is alone in the last buffer of the text stream
+         */
+        sourceIndex=(int32_t)(source-args->source);
+        if(sourceIndex>0) {
+            --sourceIndex;
+            if( U16_IS_TRAIL(args->source[sourceIndex]) &&
+                (sourceIndex==0 || U16_IS_LEAD(args->source[sourceIndex-1]))
+            ) {
+                --sourceIndex;
+            }
+        } else {
+            sourceIndex=-1;
+        }
+
+        fromUWriteUInt8(
+            cnv,
+            SHIFT_IN_STR, 1,
+            &target, (const char *)targetLimit,
+            &offsets, sourceIndex,
+            err);
+    }
+
+    /*save the state and return */
+    args->source = source;
+    args->target = (char*)target;
+}
+
+
+static void
+UConverter_toUnicode_ISO_2022_CN_OFFSETS_LOGIC(UConverterToUnicodeArgs *args,
+                                               UErrorCode* err){
+    char tempBuf[3];
+    const char *mySource = (char *) args->source;
+    UChar *myTarget = args->target;
+    const char *mySourceLimit = args->sourceLimit;
+    uint32_t targetUniChar = 0x0000;
+    uint32_t mySourceChar = 0x0000;
+    UConverterDataISO2022* myData;
+    ISO2022State *pToU2022State;
+
+    myData=(UConverterDataISO2022*)(args->converter->extraInfo);
+    pToU2022State = &myData->toU2022State;
+
+    if(myData->key != 0) {
+        /* continue with a partial escape sequence */
+        goto escape;
+    } else if(args->converter->toULength == 1 && mySource < mySourceLimit && myTarget < args->targetLimit) {
+        /* continue with a partial double-byte character */
+        mySourceChar = args->converter->toUBytes[0];
+        args->converter->toULength = 0;
+        targetUniChar = missingCharMarker;
+        goto getTrailByte;
+    }
+
+    while(mySource < mySourceLimit){
+
+        targetUniChar =missingCharMarker;
+
+        if(myTarget < args->targetLimit){
+
+            mySourceChar= (unsigned char) *mySource++;
+
+            switch(mySourceChar){
+            case UCNV_SI:
+                pToU2022State->g=0;
+                if (myData->isEmptySegment) {
+                    myData->isEmptySegment = FALSE;     /* we are handling it, reset to avoid future spurious errors */
+                    *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+                    args->converter->toUCallbackReason = UCNV_IRREGULAR;
+                    args->converter->toUBytes[0] = mySourceChar;
+                    args->converter->toULength = 1;
+                    args->target = myTarget;
+                    args->source = mySource;
+                    return;
+                }
+                continue;
+
+            case UCNV_SO:
+                if(pToU2022State->cs[1] != 0) {
+                    pToU2022State->g=1;
+                    myData->isEmptySegment = TRUE;      /* Begin a new segment, empty so far */
+                    continue;
+                } else {
+                    /* illegal to have SO before a matching designator */
+                    myData->isEmptySegment = FALSE;     /* Handling a different error, reset this to avoid future spurious errs */
+                    break;
+                }
+
+            case ESC_2022:
+                mySource--;
+escape:
+                {
+                    const char * mySourceBefore = mySource;
+                    int8_t toULengthBefore = args->converter->toULength;
+
+                    changeState_2022(args->converter,&(mySource),
+                        mySourceLimit, ISO_2022_CN,err);
+
+                    /* After SO there must be at least one character before a designator (designator error handled separately) */
+                    if(myData->key==0 && U_SUCCESS(*err) && myData->isEmptySegment) {
+                        *err = U_ILLEGAL_ESCAPE_SEQUENCE;
+                        args->converter->toUCallbackReason = UCNV_IRREGULAR;
+                        args->converter->toULength = (int8_t)(toULengthBefore + (mySource - mySourceBefore));
+                    }
+                }
+
+                /* invalid or illegal escape sequence */
+                if(U_FAILURE(*err)){
+                    args->target = myTarget;
+                    args->source = mySource;
+                    myData->isEmptySegment = FALSE;     /* Reset to avoid future spurious errors */
+                    return;
+                }
+                continue;
+
+            /* ISO-2022-CN does not use single-byte (C1) SS2 and SS3 */
+
+            case CR:
+                /*falls through*/
+            case LF:
+                uprv_memset(pToU2022State, 0, sizeof(ISO2022State));
+                /* falls through */
+            default:
+                /* convert one or two bytes */
+                myData->isEmptySegment = FALSE;
+                if(pToU2022State->g != 0) {
+                    if(mySource < mySourceLimit) {
+                        UConverterSharedData *cnv;
+                        StateEnum tempState;
+                        int32_t tempBufLen;
+                        int leadIsOk, trailIsOk;
+                        uint8_t trailByte;
+getTrailByte:
+                        trailByte = (uint8_t)*mySource;
+                        /*
+                         * Ticket 5691: consistent illegal sequences:
+                         * - We include at least the first byte in the illegal sequence.
+                         * - If any of the non-initial bytes could be the start of a character,
+                         *   we stop the illegal sequence before the first one of those.
+                         *
+                         * In ISO-2022 DBCS, if the second byte is in the 21..7e range or is
+                         * an ESC/SO/SI, we report only the first byte as the illegal sequence.
+                         * Otherwise we convert or report the pair of bytes.
+                         */
+                        leadIsOk = (uint8_t)(mySourceChar - 0x21) <= (0x7e - 0x21);
+                        trailIsOk = (uint8_t)(trailByte - 0x21) <= (0x7e - 0x21);
+                        if (leadIsOk && trailIsOk) {
+                            ++mySource;
+                            tempState = (StateEnum)pToU2022State->cs[pToU2022State->g];
+                            if(tempState >= CNS_11643_0) {
+                                cnv = myData->myConverterArray[CNS_11643];
+                                tempBuf[0] = (char) (0x80+(tempState-CNS_11643_0));
+                                tempBuf[1] = (char) (mySourceChar);
+                                tempBuf[2] = (char) trailByte;
+                                tempBufLen = 3;
+
+                            }else{
+                                cnv = myData->myConverterArray[tempState];
+                                tempBuf[0] = (char) (mySourceChar);
+                                tempBuf[1] = (char) trailByte;
+                                tempBufLen = 2;
+                            }
+                            targetUniChar = ucnv_MBCSSimpleGetNextUChar(cnv, tempBuf, tempBufLen, FALSE);
+                            mySourceChar = (mySourceChar << 8) | trailByte;
+                        } else if (!(trailIsOk || IS_2022_CONTROL(trailByte))) {
+                            /* report a pair of illegal bytes if the second byte is not a DBCS starter */
+                            ++mySource;
+                            /* add another bit so that the code below writes 2 bytes in case of error */
+                            mySourceChar = 0x10000 | (mySourceChar << 8) | trailByte;
+                        }
+                        if(pToU2022State->g>=2) {
+                            /* return from a single-shift state to the previous one */
+                            pToU2022State->g=pToU2022State->prevG;
+                        }
+                    } else {
+                        args->converter->toUBytes[0] = (uint8_t)mySourceChar;
+                        args->converter->toULength = 1;
+                        goto endloop;
+                    }
+                }
+                else{
+                    if(mySourceChar <= 0x7f) {
+                        targetUniChar = (UChar) mySourceChar;
+                    }
+                }
+                break;
+            }
+            if(targetUniChar < (missingCharMarker-1/*0xfffe*/)){
+                if(args->offsets){
+                    args->offsets[myTarget - args->target] = (int32_t)(mySource - args->source - (mySourceChar <= 0xff ? 1 : 2));
+                }
+                *(myTarget++)=(UChar)targetUniChar;
+            }
+            else if(targetUniChar > missingCharMarker){
+                /* disassemble the surrogate pair and write to output*/
+                targetUniChar-=0x0010000;
+                *myTarget = (UChar)(0xd800+(UChar)(targetUniChar>>10));
+                if(args->offsets){
+                    args->offsets[myTarget - args->target] = (int32_t)(mySource - args->source - (mySourceChar <= 0xff ? 1 : 2));
+                }
+                ++myTarget;
+                if(myTarget< args->targetLimit){
+                    *myTarget = (UChar)(0xdc00+(UChar)(targetUniChar&0x3ff));
+                    if(args->offsets){
+                        args->offsets[myTarget - args->target] = (int32_t)(mySource - args->source - (mySourceChar <= 0xff ? 1 : 2));
+                    }
+                    ++myTarget;
+                }else{
+                    args->converter->UCharErrorBuffer[args->converter->UCharErrorBufferLength++]=
+                                    (UChar)(0xdc00+(UChar)(targetUniChar&0x3ff));
+                }
+
+            }
+            else{
+                /* Call the callback function*/
+                toUnicodeCallback(args->converter,mySourceChar,targetUniChar,err);
+                break;
+            }
+        }
+        else{
+            *err =U_BUFFER_OVERFLOW_ERROR;
+            break;
+        }
+    }
+endloop:
+    args->target = myTarget;
+    args->source = mySource;
+}
+
+static void
+_ISO_2022_WriteSub(UConverterFromUnicodeArgs *args, int32_t offsetIndex, UErrorCode *err) {
+    UConverter *cnv = args->converter;
+    UConverterDataISO2022 *myConverterData=(UConverterDataISO2022 *) cnv->extraInfo;
+    ISO2022State *pFromU2022State=&myConverterData->fromU2022State;
+    char *p, *subchar;
+    char buffer[8];
+    int32_t length;
+
+    subchar=(char *)cnv->subChars;
+    length=cnv->subCharLen; /* assume length==1 for most variants */
+
+    p = buffer;
+    switch(myConverterData->locale[0]){
+    case 'j':
+        {
+            int8_t cs;
+
+            if(pFromU2022State->g == 1) {
+                /* JIS7: switch from G1 to G0 */
+                pFromU2022State->g = 0;
+                *p++ = UCNV_SI;
+            }
+
+            cs = pFromU2022State->cs[0];
+            if(cs != ASCII && cs != JISX201) {
+                /* not in ASCII or JIS X 0201: switch to ASCII */
+                pFromU2022State->cs[0] = (int8_t)ASCII;
+                *p++ = '\x1b';
+                *p++ = '\x28';
+                *p++ = '\x42';
+            }
+
+            *p++ = subchar[0];
+            break;
+        }
+    case 'c':
+        if(pFromU2022State->g != 0) {
+            /* not in ASCII mode: switch to ASCII */
+            pFromU2022State->g = 0;
+            *p++ = UCNV_SI;
+        }
+        *p++ = subchar[0];
+        break;
+    case 'k':
+        if(myConverterData->version == 0) {
+            if(length == 1) {
+                if((UBool)args->converter->fromUnicodeStatus) {
+                    /* in DBCS mode: switch to SBCS */
+                    args->converter->fromUnicodeStatus = 0;
+                    *p++ = UCNV_SI;
+                }
+                *p++ = subchar[0];
+            } else /* length == 2*/ {
+                if(!(UBool)args->converter->fromUnicodeStatus) {
+                    /* in SBCS mode: switch to DBCS */
+                    args->converter->fromUnicodeStatus = 1;
+                    *p++ = UCNV_SO;
+                }
+                *p++ = subchar[0];
+                *p++ = subchar[1];
+            }
+            break;
+        } else {
+            /* save the subconverter's substitution string */
+            uint8_t *currentSubChars = myConverterData->currentConverter->subChars;
+            int8_t currentSubCharLen = myConverterData->currentConverter->subCharLen;
+
+            /* set our substitution string into the subconverter */
+            myConverterData->currentConverter->subChars = (uint8_t *)subchar;
+            myConverterData->currentConverter->subCharLen = (int8_t)length;
+
+            /* let the subconverter write the subchar, set/retrieve fromUChar32 state */
+            args->converter = myConverterData->currentConverter;
+            myConverterData->currentConverter->fromUChar32 = cnv->fromUChar32;
+            ucnv_cbFromUWriteSub(args, 0, err);
+            cnv->fromUChar32 = myConverterData->currentConverter->fromUChar32;
+            args->converter = cnv;
+
+            /* restore the subconverter's substitution string */
+            myConverterData->currentConverter->subChars = currentSubChars;
+            myConverterData->currentConverter->subCharLen = currentSubCharLen;
+
+            if(*err == U_BUFFER_OVERFLOW_ERROR) {
+                if(myConverterData->currentConverter->charErrorBufferLength > 0) {
+                    uprv_memcpy(
+                        cnv->charErrorBuffer,
+                        myConverterData->currentConverter->charErrorBuffer,
+                        myConverterData->currentConverter->charErrorBufferLength);
+                }
+                cnv->charErrorBufferLength = myConverterData->currentConverter->charErrorBufferLength;
+                myConverterData->currentConverter->charErrorBufferLength = 0;
+            }
+            return;
+        }
+    default:
+        /* not expected */
+        break;
+    }
+    ucnv_cbFromUWriteBytes(args,
+                           buffer, (int32_t)(p - buffer),
+                           offsetIndex, err);
+}
+
+/*
+ * Structure for cloning an ISO 2022 converter into a single memory block.
+ * ucnv_safeClone() of the converter will align the entire cloneStruct,
+ * and then ucnv_safeClone() of the sub-converter may additionally align
+ * currentConverter inside the cloneStruct, for which we need the deadSpace
+ * after currentConverter.
+ * This is because UAlignedMemory may be larger than the actually
+ * necessary alignment size for the platform.
+ * The other cloneStruct fields will not be moved around,
+ * and are aligned properly with cloneStruct's alignment.
+ */
+struct cloneStruct
+{
+    UConverter cnv;
+    UConverter currentConverter;
+    UAlignedMemory deadSpace;
+    UConverterDataISO2022 mydata;
+};
+
+
+static UConverter *
+_ISO_2022_SafeClone(
+            const UConverter *cnv,
+            void *stackBuffer,
+            int32_t *pBufferSize,
+            UErrorCode *status)
+{
+    struct cloneStruct * localClone;
+    UConverterDataISO2022 *cnvData;
+    int32_t i, size;
+
+    if (*pBufferSize == 0) { /* 'preflighting' request - set needed size into *pBufferSize */
+        *pBufferSize = (int32_t)sizeof(struct cloneStruct);
+        return NULL;
+    }
+
+    cnvData = (UConverterDataISO2022 *)cnv->extraInfo;
+    localClone = (struct cloneStruct *)stackBuffer;
+
+    /* ucnv.c/ucnv_safeClone() copied the main UConverter already */
+
+    uprv_memcpy(&localClone->mydata, cnvData, sizeof(UConverterDataISO2022));
+    localClone->cnv.extraInfo = &localClone->mydata; /* set pointer to extra data */
+    localClone->cnv.isExtraLocal = TRUE;
+
+    /* share the subconverters */
+
+    if(cnvData->currentConverter != NULL) {
+        size = (int32_t)(sizeof(UConverter) + sizeof(UAlignedMemory)); /* include size of padding */
+        localClone->mydata.currentConverter =
+            ucnv_safeClone(cnvData->currentConverter,
+                            &localClone->currentConverter,
+                            &size, status);
+        if(U_FAILURE(*status)) {
+            return NULL;
+        }
+    }
+
+    for(i=0; i<UCNV_2022_MAX_CONVERTERS; ++i) {
+        if(cnvData->myConverterArray[i] != NULL) {
+            ucnv_incrementRefCount(cnvData->myConverterArray[i]);
+        }
+    }
+
+    return &localClone->cnv;
+}
+
+static void
+_ISO_2022_GetUnicodeSet(const UConverter *cnv,
+                    const USetAdder *sa,
+                    UConverterUnicodeSet which,
+                    UErrorCode *pErrorCode)
+{
+    int32_t i;
+    UConverterDataISO2022* cnvData;
+
+    if (U_FAILURE(*pErrorCode)) {
+        return;
+    }
+#ifdef U_ENABLE_GENERIC_ISO_2022
+    if (cnv->sharedData == &_ISO2022Data) {
+        /* We use UTF-8 in this case */
+        sa->addRange(sa->set, 0, 0xd7FF);
+        sa->addRange(sa->set, 0xE000, 0x10FFFF);
+        return;
+    }
+#endif
+
+    cnvData = (UConverterDataISO2022*)cnv->extraInfo;
+
+    /* open a set and initialize it with code points that are algorithmically round-tripped */
+    switch(cnvData->locale[0]){
+    case 'j':
+        /* include JIS X 0201 which is hardcoded */
+        sa->add(sa->set, 0xa5);
+        sa->add(sa->set, 0x203e);
+        if(jpCharsetMasks[cnvData->version]&CSM(ISO8859_1)) {
+            /* include Latin-1 for some variants of JP */
+            sa->addRange(sa->set, 0, 0xff);
+        } else {
+            /* include ASCII for JP */
+            sa->addRange(sa->set, 0, 0x7f);
+        }
+        if(cnvData->version==3 || cnvData->version==4 || which==UCNV_ROUNDTRIP_AND_FALLBACK_SET) {
+            /*
+             * Do not test (jpCharsetMasks[cnvData->version]&CSM(HWKANA_7BIT))!=0
+             * because the bit is on for all JP versions although only versions 3 & 4 (JIS7 & JIS8)
+             * use half-width Katakana.
+             * This is because all ISO-2022-JP variants are lenient in that they accept (in toUnicode)
+             * half-width Katakana via the ESC ( I sequence.
+             * However, we only emit (fromUnicode) half-width Katakana according to the
+             * definition of each variant.
+             *
+             * When including fallbacks,
+             * we need to include half-width Katakana Unicode code points for all JP variants because
+             * JIS X 0208 has hardcoded fallbacks for them (which map to full-width Katakana).
+             */
+            /* include half-width Katakana for JP */
+            sa->addRange(sa->set, HWKANA_START, HWKANA_END);
+        }
+        break;
+    case 'c':
+    case 'z':
+        /* include ASCII for CN */
+        sa->addRange(sa->set, 0, 0x7f);
+        break;
+    case 'k':
+        /* there is only one converter for KR, and it is not in the myConverterArray[] */
+        cnvData->currentConverter->sharedData->impl->getUnicodeSet(
+                cnvData->currentConverter, sa, which, pErrorCode);
+        /* the loop over myConverterArray[] will simply not find another converter */
+        break;
+    default:
+        break;
+    }
+
+#if 0  /* Replaced by ucnv_MBCSGetFilteredUnicodeSetForUnicode() until we implement ucnv_getUnicodeSet() with reverse fallbacks. */
+            if( (cnvData->locale[0]=='c' || cnvData->locale[0]=='z') &&
+                cnvData->version==0 && i==CNS_11643
+            ) {
+                /* special handling for non-EXT ISO-2022-CN: add only code points for CNS planes 1 and 2 */
+                ucnv_MBCSGetUnicodeSetForBytes(
+                        cnvData->myConverterArray[i],
+                        sa, UCNV_ROUNDTRIP_SET,
+                        0, 0x81, 0x82,
+                        pErrorCode);
+            }
+#endif
+
+    for (i=0; i<UCNV_2022_MAX_CONVERTERS; i++) {
+        UConverterSetFilter filter;
+        if(cnvData->myConverterArray[i]!=NULL) {
+            if( (cnvData->locale[0]=='c' || cnvData->locale[0]=='z') &&
+                cnvData->version==0 && i==CNS_11643
+            ) {
+                /*
+                 * Version-specific for CN:
+                 * CN version 0 does not map CNS planes 3..7 although
+                 * they are all available in the CNS conversion table;
+                 * CN version 1 (-EXT) does map them all.
+                 * The two versions create different Unicode sets.
+                 */
+                filter=UCNV_SET_FILTER_2022_CN;
+            } else if(cnvData->locale[0]=='j' && i==JISX208) {
+                /*
+                 * Only add code points that map to Shift-JIS codes
+                 * corresponding to JIS X 0208.
+                 */
+                filter=UCNV_SET_FILTER_SJIS;
+            } else if(i==KSC5601) {
+                /*
+                 * Some of the KSC 5601 tables (convrtrs.txt has this aliases on multiple tables)
+                 * are broader than GR94.
+                 */
+                filter=UCNV_SET_FILTER_GR94DBCS;
+            } else {
+                filter=UCNV_SET_FILTER_NONE;
+            }
+            ucnv_MBCSGetFilteredUnicodeSetForUnicode(cnvData->myConverterArray[i], sa, which, filter, pErrorCode);
+        }
+    }
+
+    /*
+     * ISO 2022 converters must not convert SO/SI/ESC despite what
+     * sub-converters do by themselves.
+     * Remove these characters from the set.
+     */
+    sa->remove(sa->set, 0x0e);
+    sa->remove(sa->set, 0x0f);
+    sa->remove(sa->set, 0x1b);
+
+    /* ISO 2022 converters do not convert C1 controls either */
+    sa->removeRange(sa->set, 0x80, 0x9f);
+}
+
+static const UConverterImpl _ISO2022Impl={
+    UCNV_ISO_2022,
+
+    NULL,
+    NULL,
+
+    _ISO2022Open,
+    _ISO2022Close,
+    _ISO2022Reset,
+
+#ifdef U_ENABLE_GENERIC_ISO_2022
+    T_UConverter_toUnicode_ISO_2022_OFFSETS_LOGIC,
+    T_UConverter_toUnicode_ISO_2022_OFFSETS_LOGIC,
+    ucnv_fromUnicode_UTF8,
+    ucnv_fromUnicode_UTF8_OFFSETS_LOGIC,
+#else
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+#endif
+    NULL,
+
+    NULL,
+    _ISO2022getName,
+    _ISO_2022_WriteSub,
+    _ISO_2022_SafeClone,
+    _ISO_2022_GetUnicodeSet
+};
+static const UConverterStaticData _ISO2022StaticData={
+    sizeof(UConverterStaticData),
+    "ISO_2022",
+    2022,
+    UCNV_IBM,
+    UCNV_ISO_2022,
+    1,
+    3, /* max 3 bytes per UChar from UTF-8 (4 bytes from surrogate _pair_) */
+    { 0x1a, 0, 0, 0 },
+    1,
+    FALSE,
+    FALSE,
+    0,
+    0,
+    { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } /* reserved */
+};
+const UConverterSharedData _ISO2022Data={
+    sizeof(UConverterSharedData),
+    ~((uint32_t) 0),
+    NULL,
+    NULL,
+    &_ISO2022StaticData,
+    FALSE,
+    &_ISO2022Impl,
+    0
+};
+
+/*************JP****************/
+static const UConverterImpl _ISO2022JPImpl={
+    UCNV_ISO_2022,
+
+    NULL,
+    NULL,
+
+    _ISO2022Open,
+    _ISO2022Close,
+    _ISO2022Reset,
+
+    UConverter_toUnicode_ISO_2022_JP_OFFSETS_LOGIC,
+    UConverter_toUnicode_ISO_2022_JP_OFFSETS_LOGIC,
+    UConverter_fromUnicode_ISO_2022_JP_OFFSETS_LOGIC,
+    UConverter_fromUnicode_ISO_2022_JP_OFFSETS_LOGIC,
+    NULL,
+
+    NULL,
+    _ISO2022getName,
+    _ISO_2022_WriteSub,
+    _ISO_2022_SafeClone,
+    _ISO_2022_GetUnicodeSet
+};
+static const UConverterStaticData _ISO2022JPStaticData={
+    sizeof(UConverterStaticData),
+    "ISO_2022_JP",
+    0,
+    UCNV_IBM,
+    UCNV_ISO_2022,
+    1,
+    6, /* max 6 bytes per UChar: 4-byte escape sequence + DBCS */
+    { 0x1a, 0, 0, 0 },
+    1,
+    FALSE,
+    FALSE,
+    0,
+    0,
+    { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } /* reserved */
+};
+static const UConverterSharedData _ISO2022JPData={
+    sizeof(UConverterSharedData),
+    ~((uint32_t) 0),
+    NULL,
+    NULL,
+    &_ISO2022JPStaticData,
+    FALSE,
+    &_ISO2022JPImpl,
+    0
+};
+
+/************* KR ***************/
+static const UConverterImpl _ISO2022KRImpl={
+    UCNV_ISO_2022,
+
+    NULL,
+    NULL,
+
+    _ISO2022Open,
+    _ISO2022Close,
+    _ISO2022Reset,
+
+    UConverter_toUnicode_ISO_2022_KR_OFFSETS_LOGIC,
+    UConverter_toUnicode_ISO_2022_KR_OFFSETS_LOGIC,
+    UConverter_fromUnicode_ISO_2022_KR_OFFSETS_LOGIC,
+    UConverter_fromUnicode_ISO_2022_KR_OFFSETS_LOGIC,
+    NULL,
+
+    NULL,
+    _ISO2022getName,
+    _ISO_2022_WriteSub,
+    _ISO_2022_SafeClone,
+    _ISO_2022_GetUnicodeSet
+};
+static const UConverterStaticData _ISO2022KRStaticData={
+    sizeof(UConverterStaticData),
+    "ISO_2022_KR",
+    0,
+    UCNV_IBM,
+    UCNV_ISO_2022,
+    1,
+    3, /* max 3 bytes per UChar: SO+DBCS */
+    { 0x1a, 0, 0, 0 },
+    1,
+    FALSE,
+    FALSE,
+    0,
+    0,
+    { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } /* reserved */
+};
+static const UConverterSharedData _ISO2022KRData={
+    sizeof(UConverterSharedData),
+    ~((uint32_t) 0),
+    NULL,
+    NULL,
+    &_ISO2022KRStaticData,
+    FALSE,
+    &_ISO2022KRImpl,
+    0
+};
+
+/*************** CN ***************/
+static const UConverterImpl _ISO2022CNImpl={
+
+    UCNV_ISO_2022,
+
+    NULL,
+    NULL,
+
+    _ISO2022Open,
+    _ISO2022Close,
+    _ISO2022Reset,
+
+    UConverter_toUnicode_ISO_2022_CN_OFFSETS_LOGIC,
+    UConverter_toUnicode_ISO_2022_CN_OFFSETS_LOGIC,
+    UConverter_fromUnicode_ISO_2022_CN_OFFSETS_LOGIC,
+    UConverter_fromUnicode_ISO_2022_CN_OFFSETS_LOGIC,
+    NULL,
+
+    NULL,
+    _ISO2022getName,
+    _ISO_2022_WriteSub,
+    _ISO_2022_SafeClone,
+    _ISO_2022_GetUnicodeSet
+};
+static const UConverterStaticData _ISO2022CNStaticData={
+    sizeof(UConverterStaticData),
+    "ISO_2022_CN",
+    0,
+    UCNV_IBM,
+    UCNV_ISO_2022,
+    1,
+    8, /* max 8 bytes per UChar: 4-byte CNS designator + 2 bytes for SS2/SS3 + DBCS */
+    { 0x1a, 0, 0, 0 },
+    1,
+    FALSE,
+    FALSE,
+    0,
+    0,
+    { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } /* reserved */
+};
+static const UConverterSharedData _ISO2022CNData={
+    sizeof(UConverterSharedData),
+    ~((uint32_t) 0),
+    NULL,
+    NULL,
+    &_ISO2022CNStaticData,
+    FALSE,
+    &_ISO2022CNImpl,
+    0
+};
+
+
+
+#endif /* #if !UCONFIG_NO_LEGACY_CONVERSION */