Check in the pristine copy of ICU 4.6...

icu46/source/common/usc_impl.c

+/*
+**********************************************************************
+*   Copyright (C) 1999-2009, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+*
+* File USC_IMPL.C
+*
+* Modification History:
+*
+*   Date        Name        Description
+*   07/08/2002  Eric Mader  Creation.
+******************************************************************************
+*/
+
+#include "unicode/uscript.h"
+#include "usc_impl.h"
+#include "cmemory.h"
+
+#define ARRAY_SIZE(array) (sizeof array  / sizeof array[0])
+
+#define PAREN_STACK_DEPTH 32
+
+#define MOD(sp) ((sp) % PAREN_STACK_DEPTH)
+#define LIMIT_INC(sp) (((sp) < PAREN_STACK_DEPTH)? (sp) + 1 : PAREN_STACK_DEPTH)
+#define INC(sp,count) (MOD((sp) + (count)))
+#define INC1(sp) (INC(sp, 1))
+#define DEC(sp,count) (MOD((sp) + PAREN_STACK_DEPTH - (count)))
+#define DEC1(sp) (DEC(sp, 1))
+#define STACK_IS_EMPTY(scriptRun) ((scriptRun)->pushCount <= 0)
+#define STACK_IS_NOT_EMPTY(scriptRun) (! STACK_IS_EMPTY(scriptRun))
+#define TOP(scriptRun) ((scriptRun)->parenStack[(scriptRun)->parenSP])
+#define SYNC_FIXUP(scriptRun) ((scriptRun)->fixupCount = 0)
+
+struct ParenStackEntry
+{
+    int32_t pairIndex;
+    UScriptCode scriptCode;
+};
+
+struct UScriptRun
+{
+    int32_t textLength;
+    const UChar *textArray;
+
+    int32_t scriptStart;
+    int32_t scriptLimit;
+    UScriptCode scriptCode;
+
+    struct ParenStackEntry parenStack[PAREN_STACK_DEPTH];
+    int32_t parenSP;
+    int32_t pushCount;
+    int32_t fixupCount;
+};
+
+static int8_t highBit(int32_t value);
+
+static const UChar32 pairedChars[] = {
+    0x0028, 0x0029, /* ascii paired punctuation */
+    0x003c, 0x003e,
+    0x005b, 0x005d,
+    0x007b, 0x007d,
+    0x00ab, 0x00bb, /* guillemets */
+    0x2018, 0x2019, /* general punctuation */
+    0x201c, 0x201d,
+    0x2039, 0x203a,
+    0x3008, 0x3009, /* chinese paired punctuation */
+    0x300a, 0x300b,
+    0x300c, 0x300d,
+    0x300e, 0x300f,
+    0x3010, 0x3011,
+    0x3014, 0x3015,
+    0x3016, 0x3017,
+    0x3018, 0x3019,
+    0x301a, 0x301b
+};
+
+static void push(UScriptRun *scriptRun, int32_t pairIndex, UScriptCode scriptCode)
+{
+    scriptRun->pushCount  = LIMIT_INC(scriptRun->pushCount);
+    scriptRun->fixupCount = LIMIT_INC(scriptRun->fixupCount);
+    
+    scriptRun->parenSP = INC1(scriptRun->parenSP);
+    scriptRun->parenStack[scriptRun->parenSP].pairIndex  = pairIndex;
+    scriptRun->parenStack[scriptRun->parenSP].scriptCode = scriptCode;
+}
+
+static void pop(UScriptRun *scriptRun)
+{
+    if (STACK_IS_EMPTY(scriptRun)) {
+        return;
+    }
+    
+    if (scriptRun->fixupCount > 0) {
+        scriptRun->fixupCount -= 1;
+    }
+    
+    scriptRun->pushCount -= 1;
+    scriptRun->parenSP = DEC1(scriptRun->parenSP);
+    
+    /* If the stack is now empty, reset the stack
+       pointers to their initial values.
+     */
+    if (STACK_IS_EMPTY(scriptRun)) {
+        scriptRun->parenSP = -1;
+    }
+}
+
+static void fixup(UScriptRun *scriptRun, UScriptCode scriptCode)
+{
+    int32_t fixupSP = DEC(scriptRun->parenSP, scriptRun->fixupCount);
+    
+    while (scriptRun->fixupCount-- > 0) {
+        fixupSP = INC1(fixupSP);
+        scriptRun->parenStack[fixupSP].scriptCode = scriptCode;
+    }
+}
+
+static int8_t
+highBit(int32_t value)
+{
+    int8_t bit = 0;
+
+    if (value <= 0) {
+        return -32;
+    }
+
+    if (value >= 1 << 16) {
+        value >>= 16;
+        bit += 16;
+    }
+
+    if (value >= 1 << 8) {
+        value >>= 8;
+        bit += 8;
+    }
+
+    if (value >= 1 << 4) {
+        value >>= 4;
+        bit += 4;
+    }
+
+    if (value >= 1 << 2) {
+        value >>= 2;
+        bit += 2;
+    }
+
+    if (value >= 1 << 1) {
+        value >>= 1;
+        bit += 1;
+    }
+
+    return bit;
+}
+
+static int32_t
+getPairIndex(UChar32 ch)
+{
+    int32_t pairedCharCount = ARRAY_SIZE(pairedChars);
+    int32_t pairedCharPower = 1 << highBit(pairedCharCount);
+    int32_t pairedCharExtra = pairedCharCount - pairedCharPower;
+
+    int32_t probe = pairedCharPower;
+    int32_t pairIndex = 0;
+
+    if (ch >= pairedChars[pairedCharExtra]) {
+        pairIndex = pairedCharExtra;
+    }
+
+    while (probe > (1 << 0)) {
+        probe >>= 1;
+
+        if (ch >= pairedChars[pairIndex + probe]) {
+            pairIndex += probe;
+        }
+    }
+
+    if (pairedChars[pairIndex] != ch) {
+        pairIndex = -1;
+    }
+
+    return pairIndex;
+}
+
+static UBool
+sameScript(UScriptCode scriptOne, UScriptCode scriptTwo)
+{
+    return scriptOne <= USCRIPT_INHERITED || scriptTwo <= USCRIPT_INHERITED || scriptOne == scriptTwo;
+}
+
+U_CAPI UScriptRun * U_EXPORT2
+uscript_openRun(const UChar *src, int32_t length, UErrorCode *pErrorCode)
+{
+    UScriptRun *result = NULL;
+
+    if (pErrorCode == NULL || U_FAILURE(*pErrorCode)) {
+        return NULL;
+    }
+
+    result = uprv_malloc(sizeof (UScriptRun));
+
+    if (result == NULL) {
+        *pErrorCode = U_MEMORY_ALLOCATION_ERROR;
+        return NULL;
+    }
+
+    uscript_setRunText(result, src, length, pErrorCode);
+
+    /* Release the UScriptRun if uscript_setRunText() returns an error */
+    if (U_FAILURE(*pErrorCode)) {
+        uprv_free(result);
+        result = NULL;
+    }
+
+    return result;
+}
+
+U_CAPI void U_EXPORT2
+uscript_closeRun(UScriptRun *scriptRun)
+{
+    if (scriptRun != NULL) {
+        uprv_free(scriptRun);
+    }
+}
+
+U_CAPI void U_EXPORT2
+uscript_resetRun(UScriptRun *scriptRun)
+{
+    if (scriptRun != NULL) {
+        scriptRun->scriptStart = 0;
+        scriptRun->scriptLimit = 0;
+        scriptRun->scriptCode  = USCRIPT_INVALID_CODE;
+        scriptRun->parenSP     = -1;
+        scriptRun->pushCount   =  0;
+        scriptRun->fixupCount  =  0;
+    }
+}
+
+U_CAPI void U_EXPORT2
+uscript_setRunText(UScriptRun *scriptRun, const UChar *src, int32_t length, UErrorCode *pErrorCode)
+{
+    if (pErrorCode == NULL || U_FAILURE(*pErrorCode)) {
+        return;
+    }
+
+    if (scriptRun == NULL || length < 0 || ((src == NULL) != (length == 0))) {
+        *pErrorCode = U_ILLEGAL_ARGUMENT_ERROR;
+        return;
+    }
+
+    scriptRun->textArray  = src;
+    scriptRun->textLength = length;
+
+    uscript_resetRun(scriptRun);
+}
+
+U_CAPI UBool U_EXPORT2
+uscript_nextRun(UScriptRun *scriptRun, int32_t *pRunStart, int32_t *pRunLimit, UScriptCode *pRunScript)
+{
+    UErrorCode error = U_ZERO_ERROR;
+
+    /* if we've fallen off the end of the text, we're done */
+    if (scriptRun == NULL || scriptRun->scriptLimit >= scriptRun->textLength) {
+        return FALSE;
+    }
+    
+    SYNC_FIXUP(scriptRun);
+    scriptRun->scriptCode = USCRIPT_COMMON;
+
+    for (scriptRun->scriptStart = scriptRun->scriptLimit; scriptRun->scriptLimit < scriptRun->textLength; scriptRun->scriptLimit += 1) {
+        UChar   high = scriptRun->textArray[scriptRun->scriptLimit];
+        UChar32 ch   = high;
+        UScriptCode sc;
+        int32_t pairIndex;
+
+        /*
+         * if the character is a high surrogate and it's not the last one
+         * in the text, see if it's followed by a low surrogate
+         */
+        if (high >= 0xD800 && high <= 0xDBFF && scriptRun->scriptLimit < scriptRun->textLength - 1) {
+            UChar low = scriptRun->textArray[scriptRun->scriptLimit + 1];
+
+            /*
+             * if it is followed by a low surrogate,
+             * consume it and form the full character
+             */
+            if (low >= 0xDC00 && low <= 0xDFFF) {
+                ch = (high - 0xD800) * 0x0400 + low - 0xDC00 + 0x10000;
+                scriptRun->scriptLimit += 1;
+            }
+        }
+
+        sc = uscript_getScript(ch, &error);
+        pairIndex = getPairIndex(ch);
+
+        /*
+         * Paired character handling:
+         *
+         * if it's an open character, push it onto the stack.
+         * if it's a close character, find the matching open on the
+         * stack, and use that script code. Any non-matching open
+         * characters above it on the stack will be poped.
+         */
+        if (pairIndex >= 0) {
+            if ((pairIndex & 1) == 0) {
+                push(scriptRun, pairIndex, scriptRun->scriptCode);
+            } else {
+                int32_t pi = pairIndex & ~1;
+
+                while (STACK_IS_NOT_EMPTY(scriptRun) && TOP(scriptRun).pairIndex != pi) {
+                    pop(scriptRun);
+                }
+
+                if (STACK_IS_NOT_EMPTY(scriptRun)) {
+                    sc = TOP(scriptRun).scriptCode;
+                }
+            }
+        }
+
+        if (sameScript(scriptRun->scriptCode, sc)) {
+            if (scriptRun->scriptCode <= USCRIPT_INHERITED && sc > USCRIPT_INHERITED) {
+                scriptRun->scriptCode = sc;
+
+                fixup(scriptRun, scriptRun->scriptCode);
+            }
+
+            /*
+             * if this character is a close paired character,
+             * pop the matching open character from the stack
+             */
+            if (pairIndex >= 0 && (pairIndex & 1) != 0) {
+                pop(scriptRun);
+            }
+        } else {
+            /*
+             * if the run broke on a surrogate pair,
+             * end it before the high surrogate
+             */
+            if (ch >= 0x10000) {
+                scriptRun->scriptLimit -= 1;
+            }
+
+            break;
+        }
+    }
+
+
+    if (pRunStart != NULL) {
+        *pRunStart = scriptRun->scriptStart;
+    }
+
+    if (pRunLimit != NULL) {
+        *pRunLimit = scriptRun->scriptLimit;
+    }
+
+    if (pRunScript != NULL) {
+        *pRunScript = scriptRun->scriptCode;
+    }
+
+    return TRUE;
+}