Check in the pristine copy of ICU 4.6...

icu46/source/common/ucnv_u8.c

+/*  
+**********************************************************************
+*   Copyright (C) 2002-2007, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+*   file name:  ucnv_u8.c
+*   encoding:   US-ASCII
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 2002jul01
+*   created by: Markus W. Scherer
+*
+*   UTF-8 converter implementation. Used to be in ucnv_utf.c.
+*
+*   Also, CESU-8 implementation, see UTR 26.
+*   The CESU-8 converter uses all the same functions as the
+*   UTF-8 converter, with a branch for converting supplementary code points.
+*/
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_CONVERSION
+
+#include "unicode/ucnv.h"
+#include "ucnv_bld.h"
+#include "ucnv_cnv.h"
+#include "cmemory.h"
+
+/* Prototypes --------------------------------------------------------------- */
+
+/* Keep these here to make finicky compilers happy */
+
+U_CFUNC void ucnv_fromUnicode_UTF8(UConverterFromUnicodeArgs *args,
+                                           UErrorCode *err);
+U_CFUNC void ucnv_fromUnicode_UTF8_OFFSETS_LOGIC(UConverterFromUnicodeArgs *args,
+                                                        UErrorCode *err);
+
+
+/* UTF-8 -------------------------------------------------------------------- */
+
+/* UTF-8 Conversion DATA
+ *   for more information see Unicode Standard 2.0, Transformation Formats Appendix A-9
+ */
+/*static const uint32_t REPLACEMENT_CHARACTER = 0x0000FFFD;*/
+#define MAXIMUM_UCS2            0x0000FFFF
+#define MAXIMUM_UTF             0x0010FFFF
+#define MAXIMUM_UCS4            0x7FFFFFFF
+#define HALF_SHIFT              10
+#define HALF_BASE               0x0010000
+#define HALF_MASK               0x3FF
+#define SURROGATE_HIGH_START    0xD800
+#define SURROGATE_HIGH_END      0xDBFF
+#define SURROGATE_LOW_START     0xDC00
+#define SURROGATE_LOW_END       0xDFFF
+
+/* -SURROGATE_LOW_START + HALF_BASE */
+#define SURROGATE_LOW_BASE      9216
+
+static const uint32_t offsetsFromUTF8[7] = {0,
+  (uint32_t) 0x00000000, (uint32_t) 0x00003080, (uint32_t) 0x000E2080,
+  (uint32_t) 0x03C82080, (uint32_t) 0xFA082080, (uint32_t) 0x82082080
+};
+
+/* END OF UTF-8 Conversion DATA */
+
+static const int8_t bytesFromUTF8[256] = {
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  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,
+  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 0, 0
+};
+
+/*
+ * Starting with Unicode 3.0.1:
+ * UTF-8 byte sequences of length N _must_ encode code points of or above utf8_minChar32[N];
+ * byte sequences with more than 4 bytes are illegal in UTF-8,
+ * which is tested with impossible values for them
+ */
+static const uint32_t
+utf8_minChar32[7]={ 0, 0, 0x80, 0x800, 0x10000, 0xffffffff, 0xffffffff };
+
+static void ucnv_toUnicode_UTF8 (UConverterToUnicodeArgs * args,
+                                  UErrorCode * err)
+{
+    UConverter *cnv = args->converter;
+    const unsigned char *mySource = (unsigned char *) args->source;
+    UChar *myTarget = args->target;
+    const unsigned char *sourceLimit = (unsigned char *) args->sourceLimit;
+    const UChar *targetLimit = args->targetLimit;
+    unsigned char *toUBytes = cnv->toUBytes;
+    UBool isCESU8 = (UBool)(cnv->sharedData == &_CESU8Data);
+    uint32_t ch, ch2 = 0;
+    int32_t i, inBytes;
+  
+    /* Restore size of current sequence */
+    if (cnv->toUnicodeStatus && myTarget < targetLimit)
+    {
+        inBytes = cnv->mode;            /* restore # of bytes to consume */
+        i = cnv->toULength;             /* restore # of bytes consumed */
+        cnv->toULength = 0;
+
+        ch = cnv->toUnicodeStatus;/*Stores the previously calculated ch from a previous call*/
+        cnv->toUnicodeStatus = 0;
+        goto morebytes;
+    }
+
+
+    while (mySource < sourceLimit && myTarget < targetLimit)
+    {
+        ch = *(mySource++);
+        if (ch < 0x80)        /* Simple case */
+        {
+            *(myTarget++) = (UChar) ch;
+        }
+        else
+        {
+            /* store the first char */
+            toUBytes[0] = (char)ch;
+            inBytes = bytesFromUTF8[ch]; /* lookup current sequence length */
+            i = 1;
+
+morebytes:
+            while (i < inBytes)
+            {
+                if (mySource < sourceLimit)
+                {
+                    toUBytes[i] = (char) (ch2 = *mySource);
+                    if (!UTF8_IS_TRAIL(ch2))
+                    {
+                        break; /* i < inBytes */
+                    }
+                    ch = (ch << 6) + ch2;
+                    ++mySource;
+                    i++;
+                }
+                else
+                {
+                    /* stores a partially calculated target*/
+                    cnv->toUnicodeStatus = ch;
+                    cnv->mode = inBytes;
+                    cnv->toULength = (int8_t) i;
+                    goto donefornow;
+                }
+            }
+
+            /* Remove the accumulated high bits */
+            ch -= offsetsFromUTF8[inBytes];
+
+            /*
+             * Legal UTF-8 byte sequences in Unicode 3.0.1 and up:
+             * - use only trail bytes after a lead byte (checked above)
+             * - use the right number of trail bytes for a given lead byte
+             * - encode a code point <= U+10ffff
+             * - use the fewest possible number of bytes for their code points
+             * - use at most 4 bytes (for i>=5 it is 0x10ffff<utf8_minChar32[])
+             *
+             * Starting with Unicode 3.2, surrogate code points must not be encoded in UTF-8.
+             * There are no irregular sequences any more.
+             * In CESU-8, only surrogates, not supplementary code points, are encoded directly.
+             */
+            if (i == inBytes && ch <= MAXIMUM_UTF && ch >= utf8_minChar32[i] &&
+                (isCESU8 ? i <= 3 : !UTF_IS_SURROGATE(ch)))
+            {
+                /* Normal valid byte when the loop has not prematurely terminated (i < inBytes) */
+                if (ch <= MAXIMUM_UCS2) 
+                {
+                    /* fits in 16 bits */
+                    *(myTarget++) = (UChar) ch;
+                }
+                else
+                {
+                    /* write out the surrogates */
+                    ch -= HALF_BASE;
+                    *(myTarget++) = (UChar) ((ch >> HALF_SHIFT) + SURROGATE_HIGH_START);
+                    ch = (ch & HALF_MASK) + SURROGATE_LOW_START;
+                    if (myTarget < targetLimit)
+                    {
+                        *(myTarget++) = (UChar)ch;
+                    }
+                    else
+                    {
+                        /* Put in overflow buffer (not handled here) */
+                        cnv->UCharErrorBuffer[0] = (UChar) ch;
+                        cnv->UCharErrorBufferLength = 1;
+                        *err = U_BUFFER_OVERFLOW_ERROR;
+                        break;
+                    }
+                }
+            }
+            else
+            {
+                cnv->toULength = (int8_t)i;
+                *err = U_ILLEGAL_CHAR_FOUND;
+                break;
+            }
+        }
+    }
+
+donefornow:
+    if (mySource < sourceLimit && myTarget >= targetLimit && U_SUCCESS(*err))
+    {
+        /* End of target buffer */
+        *err = U_BUFFER_OVERFLOW_ERROR;
+    }
+
+    args->target = myTarget;
+    args->source = (const char *) mySource;
+}
+
+static void ucnv_toUnicode_UTF8_OFFSETS_LOGIC (UConverterToUnicodeArgs * args,
+                                                UErrorCode * err)
+{
+    UConverter *cnv = args->converter;
+    const unsigned char *mySource = (unsigned char *) args->source;
+    UChar *myTarget = args->target;
+    int32_t *myOffsets = args->offsets;
+    int32_t offsetNum = 0;
+    const unsigned char *sourceLimit = (unsigned char *) args->sourceLimit;
+    const UChar *targetLimit = args->targetLimit;
+    unsigned char *toUBytes = cnv->toUBytes;
+    UBool isCESU8 = (UBool)(cnv->sharedData == &_CESU8Data);
+    uint32_t ch, ch2 = 0;
+    int32_t i, inBytes;
+
+    /* Restore size of current sequence */
+    if (cnv->toUnicodeStatus && myTarget < targetLimit)
+    {
+        inBytes = cnv->mode;            /* restore # of bytes to consume */
+        i = cnv->toULength;             /* restore # of bytes consumed */
+        cnv->toULength = 0;
+
+        ch = cnv->toUnicodeStatus;/*Stores the previously calculated ch from a previous call*/
+        cnv->toUnicodeStatus = 0;
+        goto morebytes;
+    }
+
+    while (mySource < sourceLimit && myTarget < targetLimit)
+    {
+        ch = *(mySource++);
+        if (ch < 0x80)        /* Simple case */
+        {
+            *(myTarget++) = (UChar) ch;
+            *(myOffsets++) = offsetNum++;
+        }
+        else
+        {
+            toUBytes[0] = (char)ch;
+            inBytes = bytesFromUTF8[ch];
+            i = 1;
+
+morebytes:
+            while (i < inBytes)
+            {
+                if (mySource < sourceLimit)
+                {
+                    toUBytes[i] = (char) (ch2 = *mySource);
+                    if (!UTF8_IS_TRAIL(ch2))
+                    {
+                        break; /* i < inBytes */
+                    }
+                    ch = (ch << 6) + ch2;
+                    ++mySource;
+                    i++;
+                }
+                else
+                {
+                    cnv->toUnicodeStatus = ch;
+                    cnv->mode = inBytes;
+                    cnv->toULength = (int8_t)i;
+                    goto donefornow;
+                }
+            }
+
+            /* Remove the accumulated high bits */
+            ch -= offsetsFromUTF8[inBytes];
+
+            /*
+             * Legal UTF-8 byte sequences in Unicode 3.0.1 and up:
+             * - use only trail bytes after a lead byte (checked above)
+             * - use the right number of trail bytes for a given lead byte
+             * - encode a code point <= U+10ffff
+             * - use the fewest possible number of bytes for their code points
+             * - use at most 4 bytes (for i>=5 it is 0x10ffff<utf8_minChar32[])
+             *
+             * Starting with Unicode 3.2, surrogate code points must not be encoded in UTF-8.
+             * There are no irregular sequences any more.
+             * In CESU-8, only surrogates, not supplementary code points, are encoded directly.
+             */
+            if (i == inBytes && ch <= MAXIMUM_UTF && ch >= utf8_minChar32[i] &&
+                (isCESU8 ? i <= 3 : !UTF_IS_SURROGATE(ch)))
+            {
+                /* Normal valid byte when the loop has not prematurely terminated (i < inBytes) */
+                if (ch <= MAXIMUM_UCS2) 
+                {
+                    /* fits in 16 bits */
+                    *(myTarget++) = (UChar) ch;
+                    *(myOffsets++) = offsetNum;
+                }
+                else
+                {
+                    /* write out the surrogates */
+                    ch -= HALF_BASE;
+                    *(myTarget++) = (UChar) ((ch >> HALF_SHIFT) + SURROGATE_HIGH_START);
+                    *(myOffsets++) = offsetNum;
+                    ch = (ch & HALF_MASK) + SURROGATE_LOW_START;
+                    if (myTarget < targetLimit)
+                    {
+                        *(myTarget++) = (UChar)ch;
+                        *(myOffsets++) = offsetNum;
+                    }
+                    else
+                    {
+                        cnv->UCharErrorBuffer[0] = (UChar) ch;
+                        cnv->UCharErrorBufferLength = 1;
+                        *err = U_BUFFER_OVERFLOW_ERROR;
+                    }
+                }
+                offsetNum += i;
+            }
+            else
+            {
+                cnv->toULength = (int8_t)i;
+                *err = U_ILLEGAL_CHAR_FOUND;
+                break;
+            }
+        }
+    }
+
+donefornow:
+    if (mySource < sourceLimit && myTarget >= targetLimit && U_SUCCESS(*err))
+    {   /* End of target buffer */
+        *err = U_BUFFER_OVERFLOW_ERROR;
+    }
+
+    args->target = myTarget;
+    args->source = (const char *) mySource;
+    args->offsets = myOffsets;
+}
+
+U_CFUNC void ucnv_fromUnicode_UTF8 (UConverterFromUnicodeArgs * args,
+                                    UErrorCode * err)
+{
+    UConverter *cnv = args->converter;
+    const UChar *mySource = args->source;
+    const UChar *sourceLimit = args->sourceLimit;
+    uint8_t *myTarget = (uint8_t *) args->target;
+    const uint8_t *targetLimit = (uint8_t *) args->targetLimit;
+    uint8_t *tempPtr;
+    UChar32 ch;
+    uint8_t tempBuf[4];
+    int32_t indexToWrite;
+    UBool isNotCESU8 = (UBool)(cnv->sharedData != &_CESU8Data);
+
+    if (cnv->fromUChar32 && myTarget < targetLimit)
+    {
+        ch = cnv->fromUChar32;
+        cnv->fromUChar32 = 0;
+        goto lowsurrogate;
+    }
+
+    while (mySource < sourceLimit && myTarget < targetLimit)
+    {
+        ch = *(mySource++);
+
+        if (ch < 0x80)        /* Single byte */
+        {
+            *(myTarget++) = (uint8_t) ch;
+        }
+        else if (ch < 0x800)  /* Double byte */
+        {
+            *(myTarget++) = (uint8_t) ((ch >> 6) | 0xc0);
+            if (myTarget < targetLimit)
+            {
+                *(myTarget++) = (uint8_t) ((ch & 0x3f) | 0x80);
+            }
+            else
+            {
+                cnv->charErrorBuffer[0] = (uint8_t) ((ch & 0x3f) | 0x80);
+                cnv->charErrorBufferLength = 1;
+                *err = U_BUFFER_OVERFLOW_ERROR;
+            }
+        }
+        else {
+            /* Check for surrogates */
+            if(UTF_IS_SURROGATE(ch) && isNotCESU8) {
+lowsurrogate:
+                if (mySource < sourceLimit) {
+                    /* test both code units */
+                    if(UTF_IS_SURROGATE_FIRST(ch) && UTF_IS_SECOND_SURROGATE(*mySource)) {
+                        /* convert and consume this supplementary code point */
+                        ch=UTF16_GET_PAIR_VALUE(ch, *mySource);
+                        ++mySource;
+                        /* exit this condition tree */
+                    }
+                    else {
+                        /* this is an unpaired trail or lead code unit */
+                        /* callback(illegal) */
+                        cnv->fromUChar32 = ch;
+                        *err = U_ILLEGAL_CHAR_FOUND;
+                        break;
+                    }
+                }
+                else {
+                    /* no more input */
+                    cnv->fromUChar32 = ch;
+                    break;
+                }
+            }
+
+            /* Do we write the buffer directly for speed,
+            or do we have to be careful about target buffer space? */
+            tempPtr = (((targetLimit - myTarget) >= 4) ? myTarget : tempBuf);
+
+            if (ch <= MAXIMUM_UCS2) {
+                indexToWrite = 2;
+                tempPtr[0] = (uint8_t) ((ch >> 12) | 0xe0);
+            }
+            else {
+                indexToWrite = 3;
+                tempPtr[0] = (uint8_t) ((ch >> 18) | 0xf0);
+                tempPtr[1] = (uint8_t) (((ch >> 12) & 0x3f) | 0x80);
+            }
+            tempPtr[indexToWrite-1] = (uint8_t) (((ch >> 6) & 0x3f) | 0x80);
+            tempPtr[indexToWrite] = (uint8_t) ((ch & 0x3f) | 0x80);
+
+            if (tempPtr == myTarget) {
+                /* There was enough space to write the codepoint directly. */
+                myTarget += (indexToWrite + 1);
+            }
+            else {
+                /* We might run out of room soon. Write it slowly. */
+                for (; tempPtr <= (tempBuf + indexToWrite); tempPtr++) {
+                    if (myTarget < targetLimit) {
+                        *(myTarget++) = *tempPtr;
+                    }
+                    else {
+                        cnv->charErrorBuffer[cnv->charErrorBufferLength++] = *tempPtr;
+                        *err = U_BUFFER_OVERFLOW_ERROR;
+                    }
+                }
+            }
+        }
+    }
+
+    if (mySource < sourceLimit && myTarget >= targetLimit && U_SUCCESS(*err))
+    {
+        *err = U_BUFFER_OVERFLOW_ERROR;
+    }
+
+    args->target = (char *) myTarget;
+    args->source = mySource;
+}
+
+U_CFUNC void ucnv_fromUnicode_UTF8_OFFSETS_LOGIC (UConverterFromUnicodeArgs * args,
+                                                  UErrorCode * err)
+{
+    UConverter *cnv = args->converter;
+    const UChar *mySource = args->source;
+    int32_t *myOffsets = args->offsets;
+    const UChar *sourceLimit = args->sourceLimit;
+    uint8_t *myTarget = (uint8_t *) args->target;
+    const uint8_t *targetLimit = (uint8_t *) args->targetLimit;
+    uint8_t *tempPtr;
+    UChar32 ch;
+    int32_t offsetNum, nextSourceIndex;
+    int32_t indexToWrite;
+    uint8_t tempBuf[4];
+    UBool isNotCESU8 = (UBool)(cnv->sharedData != &_CESU8Data);
+
+    if (cnv->fromUChar32 && myTarget < targetLimit)
+    {
+        ch = cnv->fromUChar32;
+        cnv->fromUChar32 = 0;
+        offsetNum = -1;
+        nextSourceIndex = 0;
+        goto lowsurrogate;
+    } else {
+        offsetNum = 0;
+    }
+
+    while (mySource < sourceLimit && myTarget < targetLimit)
+    {
+        ch = *(mySource++);
+
+        if (ch < 0x80)        /* Single byte */
+        {
+            *(myOffsets++) = offsetNum++;
+            *(myTarget++) = (char) ch;
+        }
+        else if (ch < 0x800)  /* Double byte */
+        {
+            *(myOffsets++) = offsetNum;
+            *(myTarget++) = (uint8_t) ((ch >> 6) | 0xc0);
+            if (myTarget < targetLimit)
+            {
+                *(myOffsets++) = offsetNum++;
+                *(myTarget++) = (uint8_t) ((ch & 0x3f) | 0x80);
+            }
+            else
+            {
+                cnv->charErrorBuffer[0] = (uint8_t) ((ch & 0x3f) | 0x80);
+                cnv->charErrorBufferLength = 1;
+                *err = U_BUFFER_OVERFLOW_ERROR;
+            }
+        }
+        else
+        /* Check for surrogates */
+        {
+            nextSourceIndex = offsetNum + 1;
+
+            if(UTF_IS_SURROGATE(ch) && isNotCESU8) {
+lowsurrogate:
+                if (mySource < sourceLimit) {
+                    /* test both code units */
+                    if(UTF_IS_SURROGATE_FIRST(ch) && UTF_IS_SECOND_SURROGATE(*mySource)) {
+                        /* convert and consume this supplementary code point */
+                        ch=UTF16_GET_PAIR_VALUE(ch, *mySource);
+                        ++mySource;
+                        ++nextSourceIndex;
+                        /* exit this condition tree */
+                    }
+                    else {
+                        /* this is an unpaired trail or lead code unit */
+                        /* callback(illegal) */
+                        cnv->fromUChar32 = ch;
+                        *err = U_ILLEGAL_CHAR_FOUND;
+                        break;
+                    }
+                }
+                else {
+                    /* no more input */
+                    cnv->fromUChar32 = ch;
+                    break;
+                }
+            }
+
+            /* Do we write the buffer directly for speed,
+            or do we have to be careful about target buffer space? */
+            tempPtr = (((targetLimit - myTarget) >= 4) ? myTarget : tempBuf);
+
+            if (ch <= MAXIMUM_UCS2) {
+                indexToWrite = 2;
+                tempPtr[0] = (uint8_t) ((ch >> 12) | 0xe0);
+            }
+            else {
+                indexToWrite = 3;
+                tempPtr[0] = (uint8_t) ((ch >> 18) | 0xf0);
+                tempPtr[1] = (uint8_t) (((ch >> 12) & 0x3f) | 0x80);
+            }
+            tempPtr[indexToWrite-1] = (uint8_t) (((ch >> 6) & 0x3f) | 0x80);
+            tempPtr[indexToWrite] = (uint8_t) ((ch & 0x3f) | 0x80);
+
+            if (tempPtr == myTarget) {
+                /* There was enough space to write the codepoint directly. */
+                myTarget += (indexToWrite + 1);
+                myOffsets[0] = offsetNum;
+                myOffsets[1] = offsetNum;
+                myOffsets[2] = offsetNum;
+                if (indexToWrite >= 3) {
+                    myOffsets[3] = offsetNum;
+                }
+                myOffsets += (indexToWrite + 1);
+            }
+            else {
+                /* We might run out of room soon. Write it slowly. */
+                for (; tempPtr <= (tempBuf + indexToWrite); tempPtr++) {
+                    if (myTarget < targetLimit)
+                    {
+                        *(myOffsets++) = offsetNum;
+                        *(myTarget++) = *tempPtr;
+                    }
+                    else
+                    {
+                        cnv->charErrorBuffer[cnv->charErrorBufferLength++] = *tempPtr;
+                        *err = U_BUFFER_OVERFLOW_ERROR;
+                    }
+                }
+            }
+            offsetNum = nextSourceIndex;
+        }
+    }
+
+    if (mySource < sourceLimit && myTarget >= targetLimit && U_SUCCESS(*err))
+    {
+        *err = U_BUFFER_OVERFLOW_ERROR;
+    }
+
+    args->target = (char *) myTarget;
+    args->source = mySource;
+    args->offsets = myOffsets;
+}
+
+static UChar32 ucnv_getNextUChar_UTF8(UConverterToUnicodeArgs *args,
+                                               UErrorCode *err) {
+    UConverter *cnv;
+    const uint8_t *sourceInitial;
+    const uint8_t *source;
+    uint16_t extraBytesToWrite;
+    uint8_t myByte;
+    UChar32 ch;
+    int8_t i, isLegalSequence;
+
+    /* UTF-8 only here, the framework handles CESU-8 to combine surrogate pairs */
+
+    cnv = args->converter;
+    sourceInitial = source = (const uint8_t *)args->source;
+    if (source >= (const uint8_t *)args->sourceLimit)
+    {
+        /* no input */
+        *err = U_INDEX_OUTOFBOUNDS_ERROR;
+        return 0xffff;
+    }
+
+    myByte = (uint8_t)*(source++);
+    if (myByte < 0x80)
+    {
+        args->source = (const char *)source;
+        return (UChar32)myByte;
+    }
+
+    extraBytesToWrite = (uint16_t)bytesFromUTF8[myByte];
+    if (extraBytesToWrite == 0) {
+        cnv->toUBytes[0] = myByte;
+        cnv->toULength = 1;
+        *err = U_ILLEGAL_CHAR_FOUND;
+        args->source = (const char *)source;
+        return 0xffff;
+    }
+
+    /*The byte sequence is longer than the buffer area passed*/
+    if (((const char *)source + extraBytesToWrite - 1) > args->sourceLimit)
+    {
+        /* check if all of the remaining bytes are trail bytes */
+        cnv->toUBytes[0] = myByte;
+        i = 1;
+        *err = U_TRUNCATED_CHAR_FOUND;
+        while(source < (const uint8_t *)args->sourceLimit) {
+            if(U8_IS_TRAIL(myByte = *source)) {
+                cnv->toUBytes[i++] = myByte;
+                ++source;
+            } else {
+                /* error even before we run out of input */
+                *err = U_ILLEGAL_CHAR_FOUND;
+                break;
+            }
+        }
+        cnv->toULength = i;
+        args->source = (const char *)source;
+        return 0xffff;
+    }
+
+    isLegalSequence = 1;
+    ch = myByte << 6;
+    switch(extraBytesToWrite)
+    {     
+      /* note: code falls through cases! (sic)*/ 
+    case 6:
+        ch += (myByte = *source);
+        ch <<= 6;
+        if (!UTF8_IS_TRAIL(myByte))
+        {
+            isLegalSequence = 0;
+            break;
+        }
+        ++source;
+    case 5:
+        ch += (myByte = *source);
+        ch <<= 6;
+        if (!UTF8_IS_TRAIL(myByte))
+        {
+            isLegalSequence = 0;
+            break;
+        }
+        ++source;
+    case 4:
+        ch += (myByte = *source);
+        ch <<= 6;
+        if (!UTF8_IS_TRAIL(myByte))
+        {
+            isLegalSequence = 0;
+            break;
+        }
+        ++source;
+    case 3:
+        ch += (myByte = *source);
+        ch <<= 6;
+        if (!UTF8_IS_TRAIL(myByte))
+        {
+            isLegalSequence = 0;
+            break;
+        }
+        ++source;
+    case 2:
+        ch += (myByte = *source);
+        if (!UTF8_IS_TRAIL(myByte))
+        {
+            isLegalSequence = 0;
+            break;
+        }
+        ++source;
+    };
+    ch -= offsetsFromUTF8[extraBytesToWrite];
+    args->source = (const char *)source;
+
+    /*
+     * Legal UTF-8 byte sequences in Unicode 3.0.1 and up:
+     * - use only trail bytes after a lead byte (checked above)
+     * - use the right number of trail bytes for a given lead byte
+     * - encode a code point <= U+10ffff
+     * - use the fewest possible number of bytes for their code points
+     * - use at most 4 bytes (for i>=5 it is 0x10ffff<utf8_minChar32[])
+     *
+     * Starting with Unicode 3.2, surrogate code points must not be encoded in UTF-8.
+     * There are no irregular sequences any more.
+     */
+    if (isLegalSequence &&
+        (uint32_t)ch <= MAXIMUM_UTF &&
+        (uint32_t)ch >= utf8_minChar32[extraBytesToWrite] &&
+        !U_IS_SURROGATE(ch)
+    ) {
+        return ch; /* return the code point */
+    }
+
+    for(i = 0; sourceInitial < source; ++i) {
+        cnv->toUBytes[i] = *sourceInitial++;
+    }
+    cnv->toULength = i;
+    *err = U_ILLEGAL_CHAR_FOUND;
+    return 0xffff;
+} 
+
+/* UTF-8-from-UTF-8 conversion functions ------------------------------------ */
+
+/* minimum code point values for n-byte UTF-8 sequences, n=0..4 */
+static const UChar32
+utf8_minLegal[5]={ 0, 0, 0x80, 0x800, 0x10000 };
+
+/* offsets for n-byte UTF-8 sequences that were calculated with ((lead<<6)+trail)<<6+trail... */
+static const UChar32
+utf8_offsets[7]={ 0, 0, 0x3080, 0xE2080, 0x3C82080 };
+
+/* "Convert" UTF-8 to UTF-8: Validate and copy. Modified from ucnv_DBCSFromUTF8(). */
+static void
+ucnv_UTF8FromUTF8(UConverterFromUnicodeArgs *pFromUArgs,
+                  UConverterToUnicodeArgs *pToUArgs,
+                  UErrorCode *pErrorCode) {
+    UConverter *utf8, *cnv;
+    const uint8_t *source, *sourceLimit;
+    uint8_t *target;
+    int32_t targetCapacity;
+    int32_t count;
+
+    int8_t oldToULength, toULength, toULimit;
+
+    UChar32 c;
+    uint8_t b, t1, t2;
+
+    /* set up the local pointers */
+    utf8=pToUArgs->converter;
+    cnv=pFromUArgs->converter;
+    source=(uint8_t *)pToUArgs->source;
+    sourceLimit=(uint8_t *)pToUArgs->sourceLimit;
+    target=(uint8_t *)pFromUArgs->target;
+    targetCapacity=(int32_t)(pFromUArgs->targetLimit-pFromUArgs->target);
+
+    /* get the converter state from the UTF-8 UConverter */
+    c=(UChar32)utf8->toUnicodeStatus;
+    if(c!=0) {
+        toULength=oldToULength=utf8->toULength;
+        toULimit=(int8_t)utf8->mode;
+    } else {
+        toULength=oldToULength=toULimit=0;
+    }
+
+    count=(int32_t)(sourceLimit-source)+oldToULength;
+    if(count<toULimit) {
+        /*
+         * Not enough input to complete the partial character.
+         * Jump to moreBytes below - it will not output to target.
+         */
+    } else if(targetCapacity<toULimit) {
+        /*
+         * Not enough target capacity to output the partial character.
+         * Let the standard converter handle this.
+         */
+        *pErrorCode=U_USING_DEFAULT_WARNING;
+        return;
+    } else {
+        /*
+         * Use a single counter for source and target, counting the minimum of
+         * the source length and the target capacity.
+         * As a result, the source length is checked only once per multi-byte
+         * character instead of twice.
+         *
+         * Make sure that the last byte sequence is complete, or else
+         * stop just before it.
+         * (The longest legal byte sequence has 3 trail bytes.)
+         * Count oldToULength (number of source bytes from a previous buffer)
+         * into the source length but reduce the source index by toULimit
+         * while going back over trail bytes in order to not go back into
+         * the bytes that will be read for finishing a partial
+         * sequence from the previous buffer.
+         * Let the standard converter handle edge cases.
+         */
+        int32_t i;
+
+        if(count>targetCapacity) {
+            count=targetCapacity;
+        }
+
+        i=0;
+        while(i<3 && i<(count-toULimit)) {
+            b=source[count-oldToULength-i-1];
+            if(U8_IS_TRAIL(b)) {
+                ++i;
+            } else {
+                if(i<utf8_countTrailBytes[b]) {
+                    /* stop converting before the lead byte if there are not enough trail bytes for it */
+                    count-=i+1;
+                }
+                break;
+            }
+        }
+    }
+
+    if(c!=0) {
+        utf8->toUnicodeStatus=0;
+        utf8->toULength=0;
+        goto moreBytes;
+        /* See note in ucnv_SBCSFromUTF8() about this goto. */
+    }
+
+    /* conversion loop */
+    while(count>0) {
+        b=*source++;
+        if((int8_t)b>=0) {
+            /* convert ASCII */
+            *target++=b;
+            --count;
+            continue;
+        } else {
+            if(b>0xe0) {
+                if( /* handle U+1000..U+D7FF inline */
+                    (t1=source[0]) >= 0x80 && ((b<0xed && (t1 <= 0xbf)) ||
+                                               (b==0xed && (t1 <= 0x9f))) &&
+                    (t2=source[1]) >= 0x80 && t2 <= 0xbf
+                ) {
+                    source+=2;
+                    *target++=b;
+                    *target++=t1;
+                    *target++=t2;
+                    count-=3;
+                    continue;
+                }
+            } else if(b<0xe0) {
+                if( /* handle U+0080..U+07FF inline */
+                    b>=0xc2 &&
+                    (t1=*source) >= 0x80 && t1 <= 0xbf
+                ) {
+                    ++source;
+                    *target++=b;
+                    *target++=t1;
+                    count-=2;
+                    continue;
+                }
+            } else if(b==0xe0) {
+                if( /* handle U+0800..U+0FFF inline */
+                    (t1=source[0]) >= 0xa0 && t1 <= 0xbf &&
+                    (t2=source[1]) >= 0x80 && t2 <= 0xbf
+                ) {
+                    source+=2;
+                    *target++=b;
+                    *target++=t1;
+                    *target++=t2;
+                    count-=3;
+                    continue;
+                }
+            }
+
+            /* handle "complicated" and error cases, and continuing partial characters */
+            oldToULength=0;
+            toULength=1;
+            toULimit=utf8_countTrailBytes[b]+1;
+            c=b;
+moreBytes:
+            while(toULength<toULimit) {
+                if(source<sourceLimit) {
+                    b=*source;
+                    if(U8_IS_TRAIL(b)) {
+                        ++source;
+                        ++toULength;
+                        c=(c<<6)+b;
+                    } else {
+                        break; /* sequence too short, stop with toULength<toULimit */
+                    }
+                } else {
+                    /* store the partial UTF-8 character, compatible with the regular UTF-8 converter */
+                    source-=(toULength-oldToULength);
+                    while(oldToULength<toULength) {
+                        utf8->toUBytes[oldToULength++]=*source++;
+                    }
+                    utf8->toUnicodeStatus=c;
+                    utf8->toULength=toULength;
+                    utf8->mode=toULimit;
+                    pToUArgs->source=(char *)source;
+                    pFromUArgs->target=(char *)target;
+                    return;
+                }
+            }
+
+            if( toULength==toULimit &&      /* consumed all trail bytes */
+                (toULength==3 || toULength==2) &&             /* BMP */
+                (c-=utf8_offsets[toULength])>=utf8_minLegal[toULength] &&
+                (c<=0xd7ff || 0xe000<=c)    /* not a surrogate */
+            ) {
+                /* legal byte sequence for BMP code point */
+            } else if(
+                toULength==toULimit && toULength==4 &&
+                (0x10000<=(c-=utf8_offsets[4]) && c<=0x10ffff)
+            ) {
+                /* legal byte sequence for supplementary code point */
+            } else {
+                /* error handling: illegal UTF-8 byte sequence */
+                source-=(toULength-oldToULength);
+                while(oldToULength<toULength) {
+                    utf8->toUBytes[oldToULength++]=*source++;
+                }
+                utf8->toULength=toULength;
+                pToUArgs->source=(char *)source;
+                pFromUArgs->target=(char *)target;
+                *pErrorCode=U_ILLEGAL_CHAR_FOUND;
+                return;
+            }
+
+            /* copy the legal byte sequence to the target */
+            {
+                int8_t i;
+
+                for(i=0; i<oldToULength; ++i) {
+                    *target++=utf8->toUBytes[i];
+                }
+                source-=(toULength-oldToULength);
+                for(; i<toULength; ++i) {
+                    *target++=*source++;
+                }
+                count-=toULength;
+            }
+        }
+    }
+
+    if(U_SUCCESS(*pErrorCode) && source<sourceLimit) {
+        if(target==(const uint8_t *)pFromUArgs->targetLimit) {
+            *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
+        } else {
+            b=*source;
+            toULimit=utf8_countTrailBytes[b]+1;
+            if(toULimit>(sourceLimit-source)) {
+                /* collect a truncated byte sequence */
+                toULength=0;
+                c=b;
+                for(;;) {
+                    utf8->toUBytes[toULength++]=b;
+                    if(++source==sourceLimit) {
+                        /* partial byte sequence at end of source */
+                        utf8->toUnicodeStatus=c;
+                        utf8->toULength=toULength;
+                        utf8->mode=toULimit;
+                        break;
+                    } else if(!U8_IS_TRAIL(b=*source)) {
+                        /* lead byte in trail byte position */
+                        utf8->toULength=toULength;
+                        *pErrorCode=U_ILLEGAL_CHAR_FOUND;
+                        break;
+                    }
+                    c=(c<<6)+b;
+                }
+            } else {
+                /* partial-sequence target overflow: fall back to the pivoting implementation */
+                *pErrorCode=U_USING_DEFAULT_WARNING;
+            }
+        }
+    }
+
+    /* write back the updated pointers */
+    pToUArgs->source=(char *)source;
+    pFromUArgs->target=(char *)target;
+}
+
+/* UTF-8 converter data ----------------------------------------------------- */
+
+static const UConverterImpl _UTF8Impl={
+    UCNV_UTF8,
+
+    NULL,
+    NULL,
+
+    NULL,
+    NULL,
+    NULL,
+
+    ucnv_toUnicode_UTF8,
+    ucnv_toUnicode_UTF8_OFFSETS_LOGIC,
+    ucnv_fromUnicode_UTF8,
+    ucnv_fromUnicode_UTF8_OFFSETS_LOGIC,
+    ucnv_getNextUChar_UTF8,
+
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    ucnv_getNonSurrogateUnicodeSet,
+
+    ucnv_UTF8FromUTF8,
+    ucnv_UTF8FromUTF8
+};
+
+/* The 1208 CCSID refers to any version of Unicode of UTF-8 */
+static const UConverterStaticData _UTF8StaticData={
+    sizeof(UConverterStaticData),
+    "UTF-8",
+    1208, UCNV_IBM, UCNV_UTF8,
+    1, 3, /* max 3 bytes per UChar from UTF-8 (4 bytes from surrogate _pair_) */
+    { 0xef, 0xbf, 0xbd, 0 },3,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 _UTF8Data={
+    sizeof(UConverterSharedData), ~((uint32_t) 0),
+    NULL, NULL, &_UTF8StaticData, FALSE, &_UTF8Impl,
+    0
+};
+
+/* CESU-8 converter data ---------------------------------------------------- */
+
+static const UConverterImpl _CESU8Impl={
+    UCNV_CESU8,
+
+    NULL,
+    NULL,
+
+    NULL,
+    NULL,
+    NULL,
+
+    ucnv_toUnicode_UTF8,
+    ucnv_toUnicode_UTF8_OFFSETS_LOGIC,
+    ucnv_fromUnicode_UTF8,
+    ucnv_fromUnicode_UTF8_OFFSETS_LOGIC,
+    NULL,
+
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    ucnv_getCompleteUnicodeSet
+};
+
+static const UConverterStaticData _CESU8StaticData={
+    sizeof(UConverterStaticData),
+    "CESU-8",
+    9400, /* CCSID for CESU-8 */
+    UCNV_UNKNOWN, UCNV_CESU8, 1, 3,
+    { 0xef, 0xbf, 0xbd, 0 },3,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 _CESU8Data={
+    sizeof(UConverterSharedData), ~((uint32_t) 0),
+    NULL, NULL, &_CESU8StaticData, FALSE, &_CESU8Impl,
+    0
+};
+
+#endif