scuffed-code/icu4c/source/common/ustring.c
George Rhoten 180723abc4 ICU-597 AS/400 porting changes
X-SVN-Rev: 3681
2001-02-20 01:01:03 +00:00

1141 lines
28 KiB
C

/*
*******************************************************************************
*
* Copyright (C) 1998-1999, International Business Machines
* Corporation and others. All Rights Reserved.
*
*******************************************************************************
*
* File ustring.h
*
* Modification History:
*
* Date Name Description
* 12/07/98 bertrand Creation.
*******************************************************************************
*/
#include "unicode/ustring.h"
#include "unicode/utypes.h"
#include "unicode/putil.h"
#include "unicode/ucnv.h"
#include "cstring.h"
#include "cmemory.h"
#include "umutex.h"
#include "ustr_imp.h"
/* forward declaractions of definitions for the shared default converter */
static UConverter *fgDefaultConverter = NULL;
static UConverter*
getDefaultConverter(void);
static void
releaseDefaultConverter(UConverter *converter);
/* ANSI string.h - style functions ------------------------------------------ */
#define MAX_STRLEN 0x0FFFFFFF
/* ---- String searching functions ---- */
UChar*
u_strchr(const UChar *s, UChar c)
{
while (*s && *s != c) {
++s;
}
if (*s == c)
return (UChar *)s;
return NULL;
}
/* A Boyer-Moore algorithm would be better, but that would require a hashtable
because UChar is so big. This algorithm doesn't use a lot of extra memory.
*/
U_CAPI UChar * U_EXPORT2
u_strstr(const UChar *s, const UChar *substring) {
UChar *strItr, *subItr;
if (*substring == 0) {
return (UChar *)s;
}
do {
strItr = (UChar *)s;
subItr = (UChar *)substring;
/* Only one string iterator needs checking for null terminator */
while ((*strItr != 0) && (*strItr == *subItr)) {
strItr++;
subItr++;
}
if (*subItr == 0) { /* Was the end of the substring reached? */
return (UChar *)s;
}
s++;
} while (*strItr != 0); /* Was the end of the string reached? */
return NULL; /* No match */
}
U_CAPI UChar * U_EXPORT2
u_strchr32(const UChar *s, UChar32 c) {
if(!UTF_NEED_MULTIPLE_UCHAR(c)) {
return u_strchr(s, (UChar)c);
} else {
UChar buffer[UTF_MAX_CHAR_LENGTH + 1];
UTextOffset i = 0;
UTF_APPEND_CHAR_UNSAFE(buffer, i, c);
buffer[i] = 0;
return u_strstr(s, buffer);
}
}
/* Search for a codepoint in a string that matches one of the matchSet codepoints. */
UChar *
u_strpbrk(const UChar *string, const UChar *matchSet)
{
int32_t matchLen;
UBool single = TRUE;
for (matchLen = 0; matchSet[matchLen]; matchLen++)
{
if (!UTF_IS_SINGLE(matchSet[matchLen]))
{
single = FALSE;
}
}
if (single)
{
const UChar *matchItr;
const UChar *strItr;
for (strItr = string; *strItr; strItr++)
{
for (matchItr = matchSet; *matchItr; matchItr++)
{
if (*matchItr == *strItr)
{
return (UChar *)strItr;
}
}
}
}
else
{
int32_t matchItr;
int32_t strItr;
UChar32 stringCh, matchSetCh;
int32_t stringLen = u_strlen(string);
for (strItr = 0; strItr < stringLen; strItr++)
{
UTF_GET_CHAR_SAFE(string, 0, strItr, stringLen, stringCh, TRUE);
for (matchItr = 0; matchItr < matchLen; matchItr++)
{
UTF_GET_CHAR_SAFE(matchSet, 0, matchItr, matchLen, matchSetCh, TRUE);
if (stringCh == matchSetCh && (stringCh != UTF_ERROR_VALUE
|| string[strItr] == UTF_ERROR_VALUE
|| (matchSetCh == UTF_ERROR_VALUE && !UTF_IS_SINGLE(matchSet[matchItr]))))
{
return (UChar *)string + strItr;
}
}
}
}
/* Didn't find it. */
return NULL;
}
/* Search for a codepoint in a string that matches one of the matchSet codepoints. */
int32_t
u_strcspn(const UChar *string, const UChar *matchSet)
{
const UChar *foundStr = u_strpbrk(string, matchSet);
if (foundStr == NULL)
{
return u_strlen(string);
}
return foundStr - string;
}
/* Search for a codepoint in a string that does not match one of the matchSet codepoints. */
int32_t
u_strspn(const UChar *string, const UChar *matchSet)
{
UBool single = TRUE;
UBool match = TRUE;
int32_t matchLen;
int32_t retValue;
for (matchLen = 0; matchSet[matchLen]; matchLen++)
{
if (!UTF_IS_SINGLE(matchSet[matchLen]))
{
single = FALSE;
}
}
if (single)
{
const UChar *matchItr;
const UChar *strItr;
for (strItr = string; *strItr && match; strItr++)
{
match = FALSE;
for (matchItr = matchSet; *matchItr; matchItr++)
{
if (*matchItr == *strItr)
{
match = TRUE;
break;
}
}
}
retValue = strItr - string - (match == FALSE);
}
else
{
int32_t matchItr;
int32_t strItr;
UChar32 stringCh, matchSetCh;
int32_t stringLen = u_strlen(string);
for (strItr = 0; strItr < stringLen && match; strItr++)
{
match = FALSE;
UTF_GET_CHAR_SAFE(string, 0, strItr, stringLen, stringCh, TRUE);
for (matchItr = 0; matchItr < matchLen; matchItr++)
{
UTF_GET_CHAR_SAFE(matchSet, 0, matchItr, matchLen, matchSetCh, TRUE);
if (stringCh == matchSetCh && (stringCh != UTF_ERROR_VALUE
|| string[strItr] == UTF_ERROR_VALUE
|| (matchSetCh == UTF_ERROR_VALUE && !UTF_IS_SINGLE(matchSet[matchItr]))))
{
match = TRUE;
break;
}
}
}
retValue = strItr - (match == FALSE);
}
/* Found a mismatch or didn't find it. */
return retValue;
}
/* ----- Text manipulation functions --- */
UChar*
u_strtok_r(UChar *src,
const UChar *delim,
UChar **saveState)
{
UChar *tokSource;
UChar *nextToken;
uint32_t nonDelimIdx;
if (src != NULL) {
tokSource = src;
}
else if (saveState && *saveState) {
tokSource = *saveState;
}
else {
return NULL;
}
/* Skip initial delimiters */
nonDelimIdx = u_strspn(tokSource, delim);
tokSource = &tokSource[nonDelimIdx];
nextToken = u_strpbrk(tokSource, delim);
if (nextToken != NULL) {
*(nextToken++) = 0;
*saveState = nextToken;
return tokSource;
}
else if (saveState && *saveState) {
*saveState = NULL;
return tokSource;
}
return NULL;
}
UChar*
u_strcat(UChar *dst,
const UChar *src)
{
UChar *anchor = dst; /* save a pointer to start of dst */
while(*dst != 0) { /* To end of first string */
++dst;
}
while((*dst = *src) != 0) { /* copy string 2 over */
++dst;
++src;
}
return anchor;
}
UChar*
u_strncat(UChar *dst,
const UChar *src,
int32_t n )
{
if(n > 0) {
UChar *anchor = dst; /* save a pointer to start of dst */
while(*dst != 0) { /* To end of first string */
++dst;
}
while((*dst = *src) != 0) { /* copy string 2 over */
++dst;
if(--n == 0) {
*dst = 0;
break;
}
++src;
}
return anchor;
} else {
return dst;
}
}
/* ----- Text property functions --- */
int32_t
u_strcmp(const UChar *s1,
const UChar *s2)
{
int32_t rc;
for(;;) {
rc = (int32_t)*s1 - (int32_t)*s2;
if(rc != 0 || *s1 == 0) {
return rc;
}
++s1;
++s2;
}
}
/* String compare in code point order - u_strcmp() compares in code unit order. */
U_CAPI int32_t U_EXPORT2
u_strcmpCodePointOrder(const UChar *s1, const UChar *s2) {
static const UChar utf16Fixup[32]={
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,
0x2000, 0xf800, 0xf800, 0xf800, 0xf800
};
UChar c1, c2;
int32_t diff;
/* rotate each code unit's value so that surrogates get the highest values */
for(;;) {
c1=*s1;
c1+=utf16Fixup[c1>>11]; /* additional "fix-up" line */
c2=*s2;
c2+=utf16Fixup[c2>>11]; /* additional "fix-up" line */
/* now c1 and c2 are in UTF-32-compatible order */
diff=(int32_t)c1-(int32_t)c2;
if(diff!=0 || c1==0 /* redundant: || c2==0 */) {
return diff;
}
++s1;
++s2;
}
}
int32_t
u_strncmp(const UChar *s1,
const UChar *s2,
int32_t n)
{
if(n > 0) {
int32_t rc;
for(;;) {
rc = (int32_t)*s1 - (int32_t)*s2;
if(rc != 0 || *s1 == 0 || --n == 0) {
return rc;
}
++s1;
++s2;
}
} else {
return 0;
}
}
UChar*
u_strcpy(UChar *dst,
const UChar *src)
{
UChar *anchor = dst; /* save a pointer to start of dst */
while((*dst = *src) != 0) { /* copy string 2 over */
++dst;
++src;
}
return anchor;
}
UChar*
u_strncpy(UChar *dst,
const UChar *src,
int32_t n)
{
UChar *anchor = dst; /* save a pointer to start of dst */
if(n > 0) {
while((*dst = *src) != 0) { /* copy string 2 over */
++dst;
if(--n == 0) {
*dst = 0;
break;
}
++src;
}
} else {
*dst = 0;
}
return anchor;
}
int32_t
u_strlen(const UChar *s)
{
# if U_SIZEOF_WCHAR_T == U_SIZEOF_UCHAR
return uprv_wcslen(s);
# else
const UChar *t = s;
while(*t != 0) {
++t;
}
return t - s;
#endif
}
UChar *
u_memcpy(UChar *dest, const UChar *src, int32_t count) {
return (UChar *)uprv_memcpy(dest, src, count*U_SIZEOF_UCHAR);
}
UChar *
u_memmove(UChar *dest, const UChar *src, int32_t count) {
return (UChar *)uprv_memmove(dest, src, count*U_SIZEOF_UCHAR);
}
UChar *
u_memset(UChar *dest, UChar c, int32_t count) {
UChar *ptr = dest;
UChar *limit = dest + count;
while(ptr < limit) {
*(ptr++) = c;
}
return dest;
}
/* string casing ------------------------------------------------------------ */
/*
* Implement argument checking and buffer handling
* for string case mapping as a common function.
*/
enum {
TO_LOWER,
TO_UPPER,
FOLD_CASE
};
static int32_t
u_strCaseMap(UChar *dest, int32_t destCapacity,
const UChar *src, int32_t srcLength,
const char *locale,
uint32_t options,
int32_t toWhichCase,
UErrorCode *pErrorCode) {
UChar buffer[300];
UChar *temp;
int32_t destLength;
/* check argument values */
if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
return 0;
}
if( destCapacity<0 ||
(dest==NULL && destCapacity>0) ||
src==NULL ||
srcLength<-1
) {
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
return 0;
}
/* get the string length */
if(srcLength==-1) {
srcLength=u_strlen(src);
}
/* check for overlapping source and destination */
if( (src>=dest && src<(dest+destCapacity)) ||
(dest>=src && dest<(src+srcLength))
) {
/* overlap: provide a temporary destination buffer and later copy the result */
if(destCapacity<=(sizeof(buffer)/U_SIZEOF_UCHAR)) {
/* the stack buffer is large enough */
temp=buffer;
} else {
/* allocate a buffer */
temp=(UChar *)uprv_malloc(destCapacity*U_SIZEOF_UCHAR);
if(temp==NULL) {
*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
return 0;
}
}
} else {
temp=dest;
}
if(toWhichCase==TO_LOWER) {
destLength=u_internalStrToLower(temp, destCapacity, src, srcLength,
locale, NULL, NULL, pErrorCode);
} else if(toWhichCase==TO_UPPER) {
destLength=u_internalStrToUpper(temp, destCapacity, src, srcLength,
locale, NULL, NULL, pErrorCode);
} else {
destLength=u_internalStrFoldCase(temp, destCapacity, src, srcLength,
options, NULL, NULL, pErrorCode);
}
if(temp!=dest) {
/* copy the result string to the destination buffer */
uprv_memcpy(dest, temp, destLength*U_SIZEOF_UCHAR);
if(temp!=buffer) {
uprv_free(temp);
}
}
/* zero-terminate if possible */
if(destLength<destCapacity) {
dest[destLength]=0;
}
return destLength;
}
U_CAPI int32_t U_EXPORT2
u_strToLower(UChar *dest, int32_t destCapacity,
const UChar *src, int32_t srcLength,
const char *locale,
UErrorCode *pErrorCode) {
return u_strCaseMap(dest, destCapacity, src, srcLength, locale, 0, TO_LOWER, pErrorCode);
}
U_CAPI int32_t U_EXPORT2
u_strToUpper(UChar *dest, int32_t destCapacity,
const UChar *src, int32_t srcLength,
const char *locale,
UErrorCode *pErrorCode) {
return u_strCaseMap(dest, destCapacity, src, srcLength, locale, 0, TO_UPPER, pErrorCode);
}
U_CAPI int32_t U_EXPORT2
u_strFoldCase(UChar *dest, int32_t destCapacity,
const UChar *src, int32_t srcLength,
uint32_t options,
UErrorCode *pErrorCode) {
return u_strCaseMap(dest, destCapacity, src, srcLength, NULL, options, FOLD_CASE, pErrorCode);
}
/* case-insensitive string comparisons */
U_CAPI int32_t U_EXPORT2
u_strcasecmp(const UChar *s1, const UChar *s2, uint32_t options) {
UChar t1[32], t2[32]; /* temporary buffers holding case-folded parts of s1 and s2 */
UChar32 c;
UChar c2;
int32_t pos1, pos2, len1, len2, result;
if(!uprv_haveProperties()) {
/* hardcode ASCII strcasecmp() */
UChar c1, c2;
for(;;) {
c1=*s1++;
if((uint16_t)(c1-0x41)<26) {
c1+=0x20;
}
c2=*s2++;
if((uint16_t)(c2-0x41)<26) {
c2+=0x20;
}
result=(int32_t)c1-(int32_t)c2;
if(result!=0 || c1==0) {
return result;
}
}
}
pos1=pos2=len1=len2=0;
for(;;) {
/* make sure that the temporary buffers are not empty */
if(pos1>=len1) {
c=*s1++;
if(c!=0) {
if(UTF_IS_FIRST_SURROGATE(c) && UTF_IS_SECOND_SURROGATE(c2=*s1)) {
c=UTF16_GET_PAIR_VALUE(c, c2);
++s1;
}
len1=u_internalFoldCase(c, t1, options);
pos1=0;
} else if(pos2>=len2 && *s2==0) {
return 0;
} else {
return -1;
}
}
if(pos2>=len2) {
c=*s2++;
if(c!=0) {
if(UTF_IS_FIRST_SURROGATE(c) && UTF_IS_SECOND_SURROGATE(c2=*s2)) {
c=UTF16_GET_PAIR_VALUE(c, c2);
++s2;
}
len2=u_internalFoldCase(c, t2, options);
pos2=0;
} else {
return 1;
}
}
/* compare the head code units from both folded strings */
result=(int32_t)t1[pos1++]-(int32_t)t2[pos2++];
if(result!=0) {
return result;
}
}
}
U_CFUNC int32_t
u_internalStrcasecmp(const UChar *s1, int32_t length1,
const UChar *s2, int32_t length2,
uint32_t options) {
UChar t1[32], t2[32]; /* temporary buffers holding case-folded parts of s1 and s2 */
UChar32 c;
UChar c2;
int32_t pos1, pos2, len1, len2, result;
if(!uprv_haveProperties()) {
/* hardcode ASCII strcasecmp() */
UChar c1, c2;
for(;;) {
if(length1<=0) {
if(length2<=0) {
return 0;
} else {
return -1;
}
} else if(length2<=0) {
return 1;
}
c1=*s1++;
if((uint16_t)(c1-0x41)<26) {
c1+=0x20;
}
c2=*s2++;
if((uint16_t)(c2-0x41)<26) {
c2+=0x20;
}
result=(int32_t)c1-(int32_t)c2;
if(result!=0) {
return result;
}
--length1;
--length2;
}
}
pos1=pos2=len1=len2=0;
for(;;) {
/* make sure that the temporary buffers are not empty */
if(pos1>=len1) {
if(length1>0) {
c=*s1++;
if(UTF_IS_FIRST_SURROGATE(c) && UTF_IS_SECOND_SURROGATE(c2=*s1)) {
c=UTF16_GET_PAIR_VALUE(c, c2);
++s1;
length1-=2;
} else {
--length1;
}
len1=u_internalFoldCase(c, t1, options);
pos1=0;
} else if(pos2>=len2 && length2<=0) {
return 0;
} else {
return -1;
}
}
if(pos2>=len2) {
if(length2>0) {
c=*s2++;
if(UTF_IS_FIRST_SURROGATE(c) && UTF_IS_SECOND_SURROGATE(c2=*s2)) {
c=UTF16_GET_PAIR_VALUE(c, c2);
++s2;
length2-=2;
} else {
--length2;
}
len2=u_internalFoldCase(c, t2, options);
pos2=0;
} else {
return 1;
}
}
/* compare the head code units from both folded strings */
result=(int32_t)t1[pos1++]-(int32_t)t2[pos2++];
if(result!=0) {
return result;
}
}
}
U_CAPI int32_t U_EXPORT2
u_memcasecmp(const UChar *s1, const UChar *s2, int32_t length, uint32_t options) {
return u_internalStrcasecmp(s1, length, s2, length, options);
}
U_CAPI int32_t U_EXPORT2
u_strncasecmp(const UChar *s1, const UChar *s2, int32_t n, uint32_t options) {
/*
* This is a simple, sub-optimal implementation:
* Determine the actual lengths of the strings and call u_internalStrcasecmp().
* This saves us from having an additional variant of the above strcasecmp().
*/
const UChar *s;
int32_t length1, length2;
for(s=s1, length1=0; length1<n && *s!=0; ++s, ++length1) {}
for(s=s2, length2=0; length2<n && *s!=0; ++s, ++length2) {}
return u_internalStrcasecmp(s1, length1, s2, length2, options);
}
/* conversions between char* and UChar* ------------------------------------- */
/*
returns the minimum of (the length of the null-terminated string) and n.
*/
static int32_t u_astrnlen(const char *s1, int32_t n)
{
int32_t len = 0;
if (s1)
{
while (*(s1++) && n--)
{
len++;
}
}
return len;
}
UChar* u_uastrncpy(UChar *ucs1,
const char *s2,
int32_t n)
{
UChar *target = ucs1;
UConverter *cnv = getDefaultConverter();
if(cnv != NULL) {
UErrorCode err = U_ZERO_ERROR;
ucnv_reset(cnv);
ucnv_toUnicode(cnv,
&target,
ucs1+n,
&s2,
s2+u_astrnlen(s2, n),
NULL,
TRUE,
&err);
ucnv_reset(cnv); /* be good citizens */
releaseDefaultConverter(cnv);
if(U_FAILURE(err) && (err != U_BUFFER_OVERFLOW_ERROR) ) {
*ucs1 = 0; /* failure */
}
if(target < (ucs1+n)) { /* U_BUFFER_OVERFLOW_ERROR isn't an err, just means no termination will happen. */
*target = 0; /* terminate */
}
} else {
*ucs1 = 0;
}
return ucs1;
}
UChar* u_uastrcpy(UChar *ucs1,
const char *s2 )
{
UConverter *cnv = getDefaultConverter();
if(cnv != NULL) {
UErrorCode err = U_ZERO_ERROR;
ucnv_toUChars(cnv,
ucs1,
MAX_STRLEN,
s2,
uprv_strlen(s2),
&err);
releaseDefaultConverter(cnv);
if(U_FAILURE(err)) {
*ucs1 = 0;
}
} else {
*ucs1 = 0;
}
return ucs1;
}
/*
returns the minimum of (the length of the null-terminated string) and n.
*/
static int32_t u_ustrnlen(const UChar *ucs1, int32_t n)
{
int32_t len = 0;
if (ucs1)
{
while (*(ucs1++) && n--)
{
len++;
}
}
return len;
}
char* u_austrncpy(char *s1,
const UChar *ucs2,
int32_t n)
{
char *target = s1;
UConverter *cnv = getDefaultConverter();
if(cnv != NULL) {
UErrorCode err = U_ZERO_ERROR;
ucnv_reset(cnv);
ucnv_fromUnicode(cnv,
&target,
s1+n,
&ucs2,
ucs2+u_ustrnlen(ucs2, n),
NULL,
TRUE,
&err);
ucnv_reset(cnv); /* be good citizens */
releaseDefaultConverter(cnv);
if(U_FAILURE(err) && (err != U_BUFFER_OVERFLOW_ERROR) ) {
*s1 = 0; /* failure */
}
if(target < (s1+n)) { /* U_BUFFER_OVERFLOW_ERROR isn't an err, just means no termination will happen. */
*target = 0; /* terminate */
}
} else {
*s1 = 0;
}
return s1;
}
char* u_austrcpy(char *s1,
const UChar *ucs2 )
{
UConverter *cnv = getDefaultConverter();
if(cnv != NULL) {
UErrorCode err = U_ZERO_ERROR;
int32_t len = ucnv_fromUChars(cnv,
s1,
MAX_STRLEN,
ucs2,
-1,
&err);
releaseDefaultConverter(cnv);
s1[len] = 0;
} else {
*s1 = 0;
}
return s1;
}
/* mutexed access to a shared default converter ----------------------------- */
/* this is the same implementation as in unistr.cpp */
static UConverter*
getDefaultConverter()
{
UConverter *converter = NULL;
if(fgDefaultConverter != NULL) {
umtx_lock(NULL);
/* need to check to make sure it wasn't taken out from under us */
if(fgDefaultConverter != NULL) {
converter = fgDefaultConverter;
fgDefaultConverter = NULL;
}
umtx_unlock(NULL);
}
/* if the cache was empty, create a converter */
if(converter == NULL) {
UErrorCode status = U_ZERO_ERROR;
converter = ucnv_open(NULL, &status);
if(U_FAILURE(status)) {
return NULL;
}
}
return converter;
}
static void
releaseDefaultConverter(UConverter *converter)
{
if(fgDefaultConverter == NULL) {
umtx_lock(NULL);
if(fgDefaultConverter == NULL) {
fgDefaultConverter = converter;
converter = NULL;
}
umtx_unlock(NULL);
}
if(converter != NULL) {
ucnv_close(converter);
}
}
/* u_unescape & support fns ------------------------------------------------- */
/* This map must be in ASCENDING ORDER OF THE ESCAPE CODE */
static const UChar UNESCAPE_MAP[] = {
/*" 0x22, 0x22 */
/*' 0x27, 0x27 */
/*? 0x3F, 0x3F */
/*\ 0x5C, 0x5C */
/*a*/ 0x61, 0x07,
/*b*/ 0x62, 0x08,
/*f*/ 0x66, 0x0c,
/*n*/ 0x6E, 0x0a,
/*r*/ 0x72, 0x0d,
/*t*/ 0x74, 0x09,
/*v*/ 0x76, 0x0b
};
enum { UNESCAPE_MAP_LENGTH = sizeof(UNESCAPE_MAP) / sizeof(UNESCAPE_MAP[0]) };
/* Convert one octal digit to a numeric value 0..7, or -1 on failure */
static int8_t _digit8(UChar c) {
if (c >= 0x0030 && c <= 0x0037) {
return (int8_t)(c - 0x0030);
}
return -1;
}
/* Convert one hex digit to a numeric value 0..F, or -1 on failure */
static int8_t _digit16(UChar c) {
if (c >= 0x0030 && c <= 0x0039) {
return (int8_t)(c - 0x0030);
}
if (c >= 0x0041 && c <= 0x0046) {
return (int8_t)(c - (0x0041 - 10));
}
if (c >= 0x0061 && c <= 0x0066) {
return (int8_t)(c - (0x0061 - 10));
}
return -1;
}
/* Parse a single escape sequence. Although this method deals in
* UChars, it does not use C++ or UnicodeString. This allows it to
* be used from C contexts. */
U_CAPI UChar32 U_EXPORT2
u_unescapeAt(UNESCAPE_CHAR_AT charAt,
int32_t *offset,
int32_t length,
void *context) {
int32_t start = *offset;
UChar c;
UChar32 result = 0;
int8_t n = 0;
int8_t minDig = 0;
int8_t maxDig = 0;
int8_t bitsPerDigit = 4;
int8_t dig;
int32_t i;
/* Check that offset is in range */
if (*offset < 0 || *offset >= length) {
goto err;
}
/* Fetch first UChar after '\\' */
c = charAt((*offset)++, context);
/* Convert hexadecimal and octal escapes */
switch (c) {
case 0x0075 /*'u'*/:
minDig = maxDig = 4;
break;
case 0x0055 /*'U'*/:
minDig = maxDig = 8;
break;
case 0x0078 /*'x'*/:
minDig = 1;
maxDig = 2;
break;
default:
dig = _digit8(c);
if (dig >= 0) {
minDig = 1;
maxDig = 3;
n = 1; /* Already have first octal digit */
bitsPerDigit = 3;
result = dig;
}
break;
}
if (minDig != 0) {
while (*offset < length && n < maxDig) {
c = charAt(*offset, context);
dig = (int8_t)((bitsPerDigit == 3) ? _digit8(c) : _digit16(c));
if (dig < 0) {
break;
}
result = (result << bitsPerDigit) | dig;
++(*offset);
++n;
}
if (n < minDig) {
goto err;
}
return result;
}
/* Convert C-style escapes in table */
for (i=0; i<UNESCAPE_MAP_LENGTH; i+=2) {
if (c == UNESCAPE_MAP[i]) {
return UNESCAPE_MAP[i+1];
} else if (c < UNESCAPE_MAP[i]) {
break;
}
}
/* If no special forms are recognized, then consider
* the backslash to generically escape the next character.
* Deal with surrogate pairs. */
if (UTF_IS_FIRST_SURROGATE(c) && *offset < length) {
UChar c2 = charAt(*offset, context);
if (UTF_IS_SECOND_SURROGATE(c2)) {
++(*offset);
return UTF16_GET_PAIR_VALUE(c, c2);
}
}
return c;
err:
/* Invalid escape sequence */
*offset = start; /* Reset to initial value */
return (UChar32)0xFFFFFFFF;
}
/* u_unescapeAt() callback to return a UChar from a char* */
static UChar _charPtr_charAt(int32_t offset, void *context) {
UChar c16;
/* It would be more efficient to access the invariant tables
* directly but there is no API for that. */
u_charsToUChars(((char*) context) + offset, &c16, 1);
return c16;
}
/* Append an escape-free segment of the text; used by u_unescape() */
static void _appendUChars(UChar *dest, int32_t destCapacity,
const char *src, int32_t srcLen) {
if (destCapacity < 0) {
destCapacity = 0;
}
if (srcLen > destCapacity) {
srcLen = destCapacity;
}
u_charsToUChars(src, dest, srcLen);
}
/* Do an invariant conversion of char* -> UChar*, with escape parsing */
U_CAPI int32_t U_EXPORT2
u_unescape(const char *src, UChar *dest, int32_t destCapacity) {
const char *segment = src;
int32_t i = 0;
char c;
while ((c=*src) != 0) {
/* '\\' intentionally written as compiler-specific
* character constant to correspond to compiler-specific
* char* constants. */
if (c == '\\') {
int32_t lenParsed = 0;
UChar32 c32;
if (src != segment) {
if (dest != NULL) {
_appendUChars(dest + i, destCapacity - i,
segment, src - segment);
}
i += src - segment;
}
++src; /* advance past '\\' */
c32 = u_unescapeAt(_charPtr_charAt, &lenParsed, uprv_strlen(src), (void*)src);
if (lenParsed == 0) {
goto err;
}
src += lenParsed; /* advance past escape seq. */
if (dest != NULL && UTF_CHAR_LENGTH(c32) <= (destCapacity - i)) {
UTF_APPEND_CHAR_UNSAFE(dest, i, c32);
} else {
i += UTF_CHAR_LENGTH(c32);
}
segment = src;
} else {
++src;
}
}
if (src != segment) {
if (dest != NULL) {
_appendUChars(dest + i, destCapacity - i,
segment, src - segment);
}
i += src - segment;
}
if (dest != NULL && i < destCapacity) {
dest[i] = 0;
}
return i + 1; /* add 1 for zero term */
err:
if (dest != NULL && destCapacity > 0) {
*dest = 0;
}
return 0;
}