UChar32
UCharCharacterIterator::previous32() {
if (pos > begin) {
UChar32 c;
UTF_PREV_CHAR(text, begin, pos, c);
return c;
} else {
return DONE;
}
}
UChar32
UCharCharacterIterator::last32() {
pos = end;
if(pos > begin) {
UChar32 c;
UTF_PREV_CHAR(text, begin, pos, c);
return c;
} else {
return DONE;
}
}
static int32_t
doWriteReverse(const UChar *src, int32_t srcLength,
UChar *dest, int32_t destSize,
uint16_t options,
UErrorCode *pErrorCode) {
/*
* RTL run -
*
* RTL runs need to be copied to the destination in reverse order
* of code points, not code units, to keep Unicode characters intact.
*
* The general strategy for this is to read the source text
* in backward order, collect all code units for a code point
* (and optionally following combining characters, see below),
* and copy all these code units in ascending order
* to the destination for this run.
*
* Several options request whether combining characters
* should be kept after their base characters,
* whether BiDi control characters should be removed, and
* whether characters should be replaced by their mirror-image
* equivalent Unicode characters.
*/
int32_t i, j;
UChar32 c;
/* optimize for several combinations of options */
switch(options&(UBIDI_REMOVE_BIDI_CONTROLS|UBIDI_DO_MIRRORING|UBIDI_KEEP_BASE_COMBINING)) {
case 0:
/*
* With none of the "complicated" options set, the destination
* run will have the same length as the source run,
* and there is no mirroring and no keeping combining characters
* with their base characters.
*/
if(destSize<srcLength) {
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
return srcLength;
}
destSize=srcLength;
/* preserve character integrity */
do {
/* i is always after the last code unit known to need to be kept in this segment */
i=srcLength;
/* collect code units for one base character */
UTF_BACK_1(src, 0, srcLength);
/* copy this base character */
j=srcLength;
do {
*dest++=src[j++];
} while(j<i);
} while(srcLength>0);
break;
case UBIDI_KEEP_BASE_COMBINING:
/*
* Here, too, the destination
* run will have the same length as the source run,
* and there is no mirroring.
* We do need to keep combining characters with their base characters.
*/
if(destSize<srcLength) {
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
return srcLength;
}
destSize=srcLength;
/* preserve character integrity */
do {
/* i is always after the last code unit known to need to be kept in this segment */
i=srcLength;
/* collect code units and modifier letters for one base character */
do {
UTF_PREV_CHAR(src, 0, srcLength, c);
} while(srcLength>0 && IS_COMBINING(u_charType(c)));
/* copy this "user character" */
j=srcLength;
do {
*dest++=src[j++];
} while(j<i);
} while(srcLength>0);
break;
default:
/*
* With several "complicated" options set, this is the most
* general and the slowest copying of an RTL run.
* We will do mirroring, remove BiDi controls, and
* keep combining characters with their base characters
* as requested.
*/
if(!(options&UBIDI_REMOVE_BIDI_CONTROLS)) {
i=srcLength;
} else {
/* we need to find out the destination length of the run,
which will not include the BiDi control characters */
int32_t length=srcLength;
UChar ch;
i=0;
do {
ch=*src++;
if(!IS_BIDI_CONTROL_CHAR(ch)) {
++i;
}
} while(--length>0);
src-=srcLength;
}
if(destSize<i) {
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
return i;
}
destSize=i;
/* preserve character integrity */
do {
/* i is always after the last code unit known to need to be kept in this segment */
i=srcLength;
/* collect code units for one base character */
UTF_PREV_CHAR(src, 0, srcLength, c);
if(options&UBIDI_KEEP_BASE_COMBINING) {
/* collect modifier letters for this base character */
while(srcLength>0 && IS_COMBINING(u_charType(c))) {
UTF_PREV_CHAR(src, 0, srcLength, c);
}
}
if(options&UBIDI_REMOVE_BIDI_CONTROLS && IS_BIDI_CONTROL_CHAR(c)) {
/* do not copy this BiDi control character */
continue;
}
/* copy this "user character" */
j=srcLength;
if(options&UBIDI_DO_MIRRORING) {
/* mirror only the base character */
int32_t k=0;
c=u_charMirror(c);
UTF_APPEND_CHAR_UNSAFE(dest, k, c);
dest+=k;
j+=k;
}
while(j<i) {
*dest++=src[j++];
}
} while(srcLength>0);
break;
} /* end of switch */
return destSize;
}
