// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
******************************************************************************
*
* Copyright (C) 2000-2015, International Business Machines
* Corporation and others. All Rights Reserved.
*
******************************************************************************
* file name: ubidiwrt.c
* encoding: UTF-8
* tab size: 8 (not used)
* indentation:4
*
* created on: 1999aug06
* created by: Markus W. Scherer, updated by Matitiahu Allouche
*
* This file contains implementations for BiDi functions that use
* the core algorithm and core API to write reordered text.
*/
#include "unicode/utypes.h"
#include "unicode/ustring.h"
#include "unicode/uchar.h"
#include "unicode/ubidi.h"
#include "unicode/utf16.h"
#include "cmemory.h"
#include "ustr_imp.h"
#include "ubidiimp.h"
/*
* The function implementations in this file are designed
* for UTF-16 and UTF-32, not for UTF-8.
*
* Assumptions that are not true for UTF-8:
* - Any code point always needs the same number of code units
* ("minimum-length-problem" of UTF-8)
* - The BiDi control characters need only one code unit each
*
* Further assumptions for all UTFs:
* - u_charMirror(c) needs the same number of code units as c
*/
#if UTF_SIZE==8
# error reimplement ubidi_writeReordered() for UTF-8, see comment above
#endif
#define IS_COMBINING(type) ((1UL<<(type))&(1UL<<U_NON_SPACING_MARK|1UL<<U_COMBINING_SPACING_MARK|1UL<<U_ENCLOSING_MARK))
/*
* When we have UBIDI_OUTPUT_REVERSE set on ubidi_writeReordered(), then we
* semantically write RTL runs in reverse and later reverse them again.
* Instead, we actually write them in forward order to begin with.
* However, if the RTL run was to be mirrored, we need to mirror here now
* since the implicit second reversal must not do it.
* It looks strange to do mirroring in LTR output, but it is only because
* we are writing RTL output in reverse.
*/
static int32_t
doWriteForward(const UChar *src, int32_t srcLength,
UChar *dest, int32_t destSize,
uint16_t options,
UErrorCode *pErrorCode) {
/* optimize for several combinations of options */
switch(options&(UBIDI_REMOVE_BIDI_CONTROLS|UBIDI_DO_MIRRORING)) {
case 0: {
/* simply copy the LTR run to the destination */
int32_t length=srcLength;
if(destSize<length) {
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
return srcLength;
}
do {
*dest++=*src++;
} while(--length>0);
return srcLength;
}
case UBIDI_DO_MIRRORING: {
/* do mirroring */
int32_t i=0, j=0;
UChar32 c;
if(destSize<srcLength) {
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
return srcLength;
}
do {
U16_NEXT(src, i, srcLength, c);
c=u_charMirror(c);
U16_APPEND_UNSAFE(dest, j, c);
} while(i<srcLength);
return srcLength;
}
case UBIDI_REMOVE_BIDI_CONTROLS: {
/* copy the LTR run and remove any BiDi control characters */
int32_t remaining=destSize;
UChar c;
do {
c=*src++;
if(!IS_BIDI_CONTROL_CHAR(c)) {
if(--remaining<0) {
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
/* preflight the length */
while(--srcLength>0) {
c=*src++;
if(!IS_BIDI_CONTROL_CHAR(c)) {
--remaining;
}
}
return destSize-remaining;
}
*dest++=c;
}
} while(--srcLength>0);
return destSize-remaining;
}
default: {
/* remove BiDi control characters and do mirroring */
int32_t remaining=destSize;
int32_t i, j=0;
UChar32 c;
do {
i=0;
U16_NEXT(src, i, srcLength, c);
src+=i;
srcLength-=i;
if(!IS_BIDI_CONTROL_CHAR(c)) {
remaining-=i;
if(remaining<0) {
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
/* preflight the length */
while(srcLength>0) {
c=*src++;
if(!IS_BIDI_CONTROL_CHAR(c)) {
--remaining;
}
--srcLength;
}
return destSize-remaining;
}
c=u_charMirror(c);
U16_APPEND_UNSAFE(dest, j, c);
}
} while(srcLength>0);
return j;
}
} /* end of switch */
}
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 */
U16_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 {
U16_PREV(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 */
U16_PREV(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))) {
U16_PREV(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);
U16_APPEND_UNSAFE(dest, k, c);
dest+=k;
j+=k;
}
while(j<i) {
*dest++=src[j++];
}
} while(srcLength>0);
break;
} /* end of switch */
return destSize;
}
U_CAPI int32_t U_EXPORT2
ubidi_writeReverse(const UChar *src, int32_t srcLength,
UChar *dest, int32_t destSize,
uint16_t options,
UErrorCode *pErrorCode) {
int32_t destLength;
if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
return 0;
}
/* more error checking */
if( src==NULL || srcLength<-1 ||
destSize<0 || (destSize>0 && dest==NULL))
{
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
return 0;
}
/* do input and output overlap? */
if( dest!=NULL &&
((src>=dest && src<dest+destSize) ||
(dest>=src && dest<src+srcLength)))
{
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
return 0;
}
if(srcLength==-1) {
srcLength=u_strlen(src);
}
if(srcLength>0) {
destLength=doWriteReverse(src, srcLength, dest, destSize, options, pErrorCode);
} else {
/* nothing to do */
destLength=0;
}
return u_terminateUChars(dest, destSize, destLength, pErrorCode);
}
U_CAPI int32_t U_EXPORT2
ubidi_writeReordered(UBiDi *pBiDi,
UChar *dest, int32_t destSize,
uint16_t options,
UErrorCode *pErrorCode) {
const UChar *text;
UChar *saveDest;
int32_t length, destCapacity;
int32_t run, runCount, logicalStart, runLength;
if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
return 0;
}
/* more error checking */
if( pBiDi==NULL ||
(text=pBiDi->text)==NULL || (length=pBiDi->length)<0 ||
destSize<0 || (destSize>0 && dest==NULL))
{
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
return 0;
}
/* do input and output overlap? */
if( dest!=NULL &&
((text>=dest && text<dest+destSize) ||
(dest>=text && dest<text+pBiDi->originalLength)))
{
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
return 0;
}
if(length==0) {
/* nothing to do */
return u_terminateUChars(dest, destSize, 0, pErrorCode);
}
runCount=ubidi_countRuns(pBiDi, pErrorCode);
if(U_FAILURE(*pErrorCode)) {
return 0;
}
/* destSize shrinks, later destination length=destCapacity-destSize */
saveDest=dest;
destCapacity=destSize;
/*
* Option "insert marks" implies UBIDI_INSERT_LRM_FOR_NUMERIC if the
* reordering mode (checked below) is appropriate.
*/
if(pBiDi->reorderingOptions & UBIDI_OPTION_INSERT_MARKS) {
options|=UBIDI_INSERT_LRM_FOR_NUMERIC;
options&=~UBIDI_REMOVE_BIDI_CONTROLS;
}
/*
* Option "remove controls" implies UBIDI_REMOVE_BIDI_CONTROLS
* and cancels UBIDI_INSERT_LRM_FOR_NUMERIC.
*/
if(pBiDi->reorderingOptions & UBIDI_OPTION_REMOVE_CONTROLS) {
options|=UBIDI_REMOVE_BIDI_CONTROLS;
options&=~UBIDI_INSERT_LRM_FOR_NUMERIC;
}
/*
* If we do not perform the "inverse BiDi" algorithm, then we
* don't need to insert any LRMs, and don't need to test for it.
*/
if((pBiDi->reorderingMode != UBIDI_REORDER_INVERSE_NUMBERS_AS_L) &&
(pBiDi->reorderingMode != UBIDI_REORDER_INVERSE_LIKE_DIRECT) &&
(pBiDi->reorderingMode != UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL) &&
(pBiDi->reorderingMode != UBIDI_REORDER_RUNS_ONLY)) {
options&=~UBIDI_INSERT_LRM_FOR_NUMERIC;
}
/*
* Iterate through all visual runs and copy the run text segments to
* the destination, according to the options.
*
* The tests for where to insert LRMs ignore the fact that there may be
* BN codes or non-BMP code points at the beginning and end of a run;
* they may insert LRMs unnecessarily but the tests are faster this way
* (this would have to be improved for UTF-8).
*
* Note that the only errors that are set by doWriteXY() are buffer overflow
* errors. Ignore them until the end, and continue for preflighting.
*/
if(!(options&UBIDI_OUTPUT_REVERSE)) {
/* forward output */
if(!(options&UBIDI_INSERT_LRM_FOR_NUMERIC)) {
/* do not insert BiDi controls */
for(run=0; run<runCount; ++run) {
if(UBIDI_LTR==ubidi_getVisualRun(pBiDi, run, &logicalStart, &runLength)) {
runLength=doWriteForward(text+logicalStart, runLength,
dest, destSize,
(uint16_t)(options&~UBIDI_DO_MIRRORING), pErrorCode);
} else {
runLength=doWriteReverse(text+logicalStart, runLength,
dest, destSize,
options, pErrorCode);
}
if(dest!=NULL) {
dest+=runLength;
}
destSize-=runLength;
}
} else {
/* insert BiDi controls for "inverse BiDi" */
const DirProp *dirProps=pBiDi->dirProps;
const UChar *src;
UChar uc;
UBiDiDirection dir;
int32_t markFlag;
for(run=0; run<runCount; ++run) {
dir=ubidi_getVisualRun(pBiDi, run, &logicalStart, &runLength);
src=text+logicalStart;
/* check if something relevant in insertPoints */
markFlag=pBiDi->runs[run].insertRemove;
if(markFlag<0) { /* BiDi controls count */
markFlag=0;
}
if(UBIDI_LTR==dir) {
if((pBiDi->isInverse) &&
(/*run>0 &&*/ dirProps[logicalStart]!=L)) {
markFlag |= LRM_BEFORE;
}
if (markFlag & LRM_BEFORE) {
uc=LRM_CHAR;
}
else if (markFlag & RLM_BEFORE) {
uc=RLM_CHAR;
}
else uc=0;
if(uc) {
if(destSize>0) {
*dest++=uc;
}
--destSize;
}
runLength=doWriteForward(src, runLength,
dest, destSize,
(uint16_t)(options&~UBIDI_DO_MIRRORING), pErrorCode);
if(dest!=NULL) {
dest+=runLength;
}
destSize-=runLength;
if((pBiDi->isInverse) &&
(/*run<runCount-1 &&*/ dirProps[logicalStart+runLength-1]!=L)) {
markFlag |= LRM_AFTER;
}
if (markFlag & LRM_AFTER) {
uc=LRM_CHAR;
}
else if (markFlag & RLM_AFTER) {
uc=RLM_CHAR;
}
else uc=0;
if(uc) {
if(destSize>0) {
*dest++=uc;
}
--destSize;
}
} else { /* RTL run */
if((pBiDi->isInverse) &&
(/*run>0 &&*/ !(MASK_R_AL&DIRPROP_FLAG(dirProps[logicalStart+runLength-1])))) {
markFlag |= RLM_BEFORE;
}
if (markFlag & LRM_BEFORE) {
uc=LRM_CHAR;
}
else if (markFlag & RLM_BEFORE) {
uc=RLM_CHAR;
}
else uc=0;
if(uc) {
if(destSize>0) {
*dest++=uc;
}
--destSize;
}
runLength=doWriteReverse(src, runLength,
dest, destSize,
options, pErrorCode);
if(dest!=NULL) {
dest+=runLength;
}
destSize-=runLength;
if((pBiDi->isInverse) &&
(/*run<runCount-1 &&*/ !(MASK_R_AL&DIRPROP_FLAG(dirProps[logicalStart])))) {
markFlag |= RLM_AFTER;
}
if (markFlag & LRM_AFTER) {
uc=LRM_CHAR;
}
else if (markFlag & RLM_AFTER) {
uc=RLM_CHAR;
}
else uc=0;
if(uc) {
if(destSize>0) {
*dest++=uc;
}
--destSize;
}
}
}
}
} else {
/* reverse output */
if(!(options&UBIDI_INSERT_LRM_FOR_NUMERIC)) {
/* do not insert BiDi controls */
for(run=runCount; --run>=0;) {
if(UBIDI_LTR==ubidi_getVisualRun(pBiDi, run, &logicalStart, &runLength)) {
runLength=doWriteReverse(text+logicalStart, runLength,
dest, destSize,
(uint16_t)(options&~UBIDI_DO_MIRRORING), pErrorCode);
} else {
runLength=doWriteForward(text+logicalStart, runLength,
dest, destSize,
options, pErrorCode);
}
if(dest!=NULL) {
dest+=runLength;
}
destSize-=runLength;
}
} else {
/* insert BiDi controls for "inverse BiDi" */
const DirProp *dirProps=pBiDi->dirProps;
const UChar *src;
UBiDiDirection dir;
for(run=runCount; --run>=0;) {
/* reverse output */
dir=ubidi_getVisualRun(pBiDi, run, &logicalStart, &runLength);
src=text+logicalStart;
if(UBIDI_LTR==dir) {
if(/*run<runCount-1 &&*/ dirProps[logicalStart+runLength-1]!=L) {
if(destSize>0) {
*dest++=LRM_CHAR;
}
--destSize;
}
runLength=doWriteReverse(src, runLength,
dest, destSize,
(uint16_t)(options&~UBIDI_DO_MIRRORING), pErrorCode);
if(dest!=NULL) {
dest+=runLength;
}
destSize-=runLength;
if(/*run>0 &&*/ dirProps[logicalStart]!=L) {
if(destSize>0) {
*dest++=LRM_CHAR;
}
--destSize;
}
} else {
if(/*run<runCount-1 &&*/ !(MASK_R_AL&DIRPROP_FLAG(dirProps[logicalStart]))) {
if(destSize>0) {
*dest++=RLM_CHAR;
}
--destSize;
}
runLength=doWriteForward(src, runLength,
dest, destSize,
options, pErrorCode);
if(dest!=NULL) {
dest+=runLength;
}
destSize-=runLength;
if(/*run>0 &&*/ !(MASK_R_AL&DIRPROP_FLAG(dirProps[logicalStart+runLength-1]))) {
if(destSize>0) {
*dest++=RLM_CHAR;
}
--destSize;
}
}
}
}
}
return u_terminateUChars(saveDest, destCapacity, destCapacity-destSize, pErrorCode);
}