scuffed-code/icu4c/source/common/usc_impl.c
2002-08-02 21:06:29 +00:00

331 lines
8.6 KiB
C

/*
**********************************************************************
* Copyright (C) 1999-2002, 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 128
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;
};
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 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 index = 0;
if (ch >= pairedChars[pairedCharExtra]) {
index = pairedCharExtra;
}
while (probe > (1 << 0)) {
probe >>= 1;
if (ch >= pairedChars[index + probe]) {
index += probe;
}
}
if (pairedChars[index] != ch) {
index = -1;
}
return index;
}
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;
}
}
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)
{
int32_t startSP = -1; /* used to find the first new open character */
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;
}
startSP = scriptRun->parenSP;
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) {
/*
* If the paren stack is full, empty it. This
* means that deeply nested paired punctuation
* characters will be ignored, but that's an unusual
* case, and it's better to ignore them than to
* write off the end of the stack...
*/
if (++scriptRun->parenSP >= PAREN_STACK_DEPTH) {
scriptRun->parenSP = 0;
}
scriptRun->parenStack[scriptRun->parenSP].pairIndex = pairIndex;
scriptRun->parenStack[scriptRun->parenSP].scriptCode = scriptRun->scriptCode;
} else if (scriptRun->parenSP >= 0) {
int32_t pi = pairIndex & ~1;
while (scriptRun->parenSP >= 0 && scriptRun->parenStack[scriptRun->parenSP].pairIndex != pi) {
scriptRun->parenSP -= 1;
}
if (scriptRun->parenSP < startSP) {
startSP = scriptRun->parenSP;
}
if (scriptRun->parenSP >= 0) {
sc = scriptRun->parenStack[scriptRun->parenSP].scriptCode;
}
}
}
if (sameScript(scriptRun->scriptCode, sc)) {
if (scriptRun->scriptCode <= USCRIPT_INHERITED && sc > USCRIPT_INHERITED) {
scriptRun->scriptCode = sc;
/*
* now that we have a final script code, fix any open
* characters we pushed before we knew the script code.
*/
while (startSP < scriptRun->parenSP) {
scriptRun->parenStack[++startSP].scriptCode = scriptRun->scriptCode;
}
}
/*
* if this character is a close paired character,
* pop it from the stack
*/
if (pairIndex >= 0 && (pairIndex & 1) != 0 && scriptRun->parenSP >= 0) {
scriptRun->parenSP -= 1;
startSP -= 1;
}
} 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;
}