573 lines
19 KiB
C
573 lines
19 KiB
C
/*
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******************************************************************************
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*
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* Copyright (C) 2000-2001, International Business Machines
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* Corporation and others. All Rights Reserved.
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*
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******************************************************************************
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* file name: ubidiwrt.c
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* encoding: US-ASCII
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* tab size: 8 (not used)
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* indentation:4
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*
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* created on: 1999aug06
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* created by: Markus W. Scherer
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*
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* This file contains implementations for BiDi functions that use
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* the core algorithm and core API to write reordered text.
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*/
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/* set import/export definitions */
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#ifndef U_COMMON_IMPLEMENTATION
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# define U_COMMON_IMPLEMENTATION
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#endif
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#include "cmemory.h"
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#include "unicode/utypes.h"
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#include "unicode/ustring.h"
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#include "unicode/uchar.h"
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#include "unicode/ubidi.h"
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#include "ubidiimp.h"
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/*
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* The function implementations in this file are designed
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* for UTF-16 and UTF-32, not for UTF-8.
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*
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* Assumptions that are not true for UTF-8:
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* - Any code point always needs the same number of code units
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* ("minimum-length-problem" of UTF-8)
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* - The BiDi control characters need only one code unit each
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*
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* Further assumptions for all UTFs:
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* - u_charMirror(c) needs the same number of code units as c
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*/
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#if UTF_SIZE==8
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# error reimplement ubidi_writeReordered() for UTF-8, see comment above
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#endif
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/** BiDi control code points */
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enum {
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LRM_CHAR=0x200e,
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RLM_CHAR,
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LRE_CHAR=0x202a,
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RLE_CHAR,
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PDF_CHAR,
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LRO_CHAR,
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RLO_CHAR
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};
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#define IS_BIDI_CONTROL_CHAR(c) (((uint32_t)(c)&0xfffffffe)==LRM_CHAR || (uint32_t)((c)-LRE_CHAR)<5)
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#define IS_COMBINING(type) ((1UL<<(type))&(1UL<<U_NON_SPACING_MARK|1UL<<U_COMBINING_SPACING_MARK|1UL<<U_ENCLOSING_MARK))
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/*
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* When we have UBIDI_OUTPUT_REVERSE set on ubidi_writeReordered(), then we
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* semantically write RTL runs in reverse and later reverse them again.
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* Instead, we actually write them in forward order to begin with.
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* However, if the RTL run was to be mirrored, we need to mirror here now
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* since the implicit second reversal must not do it.
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* It looks strange to do mirroring in LTR output, but it is only because
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* we are writing RTL output in reverse.
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*/
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static UTextOffset
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doWriteForward(const UChar *src, int32_t srcLength,
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UChar *dest, int32_t destSize,
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uint16_t options,
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UErrorCode *pErrorCode) {
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/* optimize for several combinations of options */
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switch(options&(UBIDI_REMOVE_BIDI_CONTROLS|UBIDI_DO_MIRRORING)) {
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case 0: {
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/* simply copy the LTR run to the destination */
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int32_t length=srcLength;
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if(destSize<length) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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do {
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*dest++=*src++;
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} while(--length>0);
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return srcLength;
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}
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case UBIDI_DO_MIRRORING: {
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/* do mirroring */
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UTextOffset i=0, j=0;
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UChar32 c;
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if(destSize<srcLength) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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do {
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UTF_NEXT_CHAR(src, i, srcLength, c);
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c=u_charMirror(c);
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UTF_APPEND_CHAR_UNSAFE(dest, j, c);
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} while(i<srcLength);
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return srcLength;
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}
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case UBIDI_REMOVE_BIDI_CONTROLS: {
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/* copy the LTR run and remove any BiDi control characters */
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int32_t remaining=destSize;
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UChar c;
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do {
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c=*src++;
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if(!IS_BIDI_CONTROL_CHAR(c)) {
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if(--remaining<0) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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*dest++=c;
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}
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} while(--srcLength>0);
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return destSize-remaining;
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}
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default: {
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/* remove BiDi control characters and do mirroring */
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int32_t remaining=destSize;
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UTextOffset i, j=0;
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UChar32 c;
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do {
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i=0;
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UTF_NEXT_CHAR(src, i, srcLength, c);
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src+=i;
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srcLength-=i;
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if(!IS_BIDI_CONTROL_CHAR(c)) {
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remaining-=i;
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if(remaining<0) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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c=u_charMirror(c);
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UTF_APPEND_CHAR_UNSAFE(dest, j, c);
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}
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} while(srcLength>0);
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return j;
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}
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} /* end of switch */
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}
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static UTextOffset
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doWriteReverse(const UChar *src, int32_t srcLength,
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UChar *dest, int32_t destSize,
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uint16_t options,
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UErrorCode *pErrorCode) {
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/*
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* RTL run -
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*
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* RTL runs need to be copied to the destination in reverse order
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* of code points, not code units, to keep Unicode characters intact.
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*
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* The general strategy for this is to read the source text
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* in backward order, collect all code units for a code point
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* (and optionally following combining characters, see below),
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* and copy all these code units in ascending order
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* to the destination for this run.
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*
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* Several options request whether combining characters
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* should be kept after their base characters,
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* whether BiDi control characters should be removed, and
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* whether characters should be replaced by their mirror-image
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* equivalent Unicode characters.
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*/
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UTextOffset i, j;
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UChar32 c;
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/* optimize for several combinations of options */
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switch(options&(UBIDI_REMOVE_BIDI_CONTROLS|UBIDI_DO_MIRRORING|UBIDI_KEEP_BASE_COMBINING)) {
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case 0:
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/*
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* With none of the "complicated" options set, the destination
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* run will have the same length as the source run,
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* and there is no mirroring and no keeping combining characters
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* with their base characters.
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*/
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if(destSize<srcLength) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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destSize=srcLength;
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/* preserve character integrity */
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do {
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/* i is always after the last code unit known to need to be kept in this segment */
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i=srcLength;
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/* collect code units for one base character */
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UTF_BACK_1(src, 0, srcLength);
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/* copy this base character */
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j=srcLength;
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do {
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*dest++=src[j++];
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} while(j<i);
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} while(srcLength>0);
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break;
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case UBIDI_KEEP_BASE_COMBINING:
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/*
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* Here, too, the destination
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* run will have the same length as the source run,
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* and there is no mirroring.
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* We do need to keep combining characters with their base characters.
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*/
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if(destSize<srcLength) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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destSize=srcLength;
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/* preserve character integrity */
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do {
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/* i is always after the last code unit known to need to be kept in this segment */
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i=srcLength;
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/* collect code units and modifier letters for one base character */
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do {
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UTF_PREV_CHAR(src, 0, srcLength, c);
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} while(srcLength>0 && IS_COMBINING(u_charType(c)));
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/* copy this "user character" */
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j=srcLength;
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do {
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*dest++=src[j++];
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} while(j<i);
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} while(srcLength>0);
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break;
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default:
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/*
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* With several "complicated" options set, this is the most
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* general and the slowest copying of an RTL run.
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* We will do mirroring, remove BiDi controls, and
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* keep combining characters with their base characters
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* as requested.
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*/
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if(!(options&UBIDI_REMOVE_BIDI_CONTROLS)) {
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i=srcLength;
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} else {
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/* we need to find out the destination length of the run,
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which will not include the BiDi control characters */
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int32_t length=srcLength;
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UChar ch;
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i=0;
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do {
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ch=*src++;
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if(!IS_BIDI_CONTROL_CHAR(ch)) {
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++i;
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}
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} while(--length>0);
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src-=srcLength;
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}
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if(destSize<i) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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destSize=i;
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/* preserve character integrity */
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do {
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/* i is always after the last code unit known to need to be kept in this segment */
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i=srcLength;
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/* collect code units for one base character */
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UTF_PREV_CHAR(src, 0, srcLength, c);
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if(options&UBIDI_KEEP_BASE_COMBINING) {
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/* collect modifier letters for this base character */
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while(srcLength>0 && IS_COMBINING(u_charType(c))) {
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UTF_PREV_CHAR(src, 0, srcLength, c);
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}
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}
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if(options&UBIDI_REMOVE_BIDI_CONTROLS && IS_BIDI_CONTROL_CHAR(c)) {
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/* do not copy this BiDi control character */
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continue;
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}
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/* copy this "user character" */
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j=srcLength;
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if(options&UBIDI_DO_MIRRORING) {
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/* mirror only the base character */
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UTextOffset k=0;
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c=u_charMirror(c);
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UTF_APPEND_CHAR_UNSAFE(dest, k, c);
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dest+=k;
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j+=k;
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}
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while(j<i) {
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*dest++=src[j++];
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}
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} while(srcLength>0);
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break;
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} /* end of switch */
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return destSize;
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}
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U_CAPI UTextOffset U_EXPORT2
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ubidi_writeReverse(const UChar *src, int32_t srcLength,
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UChar *dest, int32_t destSize,
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uint16_t options,
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UErrorCode *pErrorCode) {
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if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
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return 0;
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}
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/* more error checking */
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if( src==NULL || srcLength<0 ||
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dest==NULL || destSize<=0)
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{
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*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
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return 0;
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}
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/* do input and output overlap? */
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if((src>=dest && src<dest+destSize) ||
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(dest>=src && dest<src+srcLength))
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{
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*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
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return 0;
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}
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if(srcLength>0) {
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return doWriteReverse(src, srcLength, dest, destSize, options, pErrorCode);
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} else {
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/* nothing to do */
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return 0;
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}
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}
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#define MASK_R_AL (1UL<<U_RIGHT_TO_LEFT|1UL<<U_RIGHT_TO_LEFT_ARABIC)
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U_CAPI UTextOffset U_EXPORT2
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ubidi_writeReordered(UBiDi *pBiDi,
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UChar *dest, int32_t destSize,
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uint16_t options,
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UErrorCode *pErrorCode) {
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const UChar *text;
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UChar *oldDest=dest;
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int32_t length;
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UTextOffset run, runCount, logicalStart, runLength;
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if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
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return 0;
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}
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/* more error checking */
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if( pBiDi==NULL ||
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(text=ubidi_getText(pBiDi))==NULL || (length=ubidi_getLength(pBiDi))<0 ||
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dest==NULL || destSize<=0
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) {
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*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
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return 0;
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}
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/* do input and output overlap? */
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if((text>=dest && text<dest+destSize) ||
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(dest>=text && dest<text+length))
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{
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*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
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return 0;
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}
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if(length==0) {
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/* nothing to do */
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return 0;
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}
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runCount=ubidi_countRuns(pBiDi, pErrorCode);
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if(U_FAILURE(*pErrorCode)) {
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return 0;
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}
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/*
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* If we do not perform the "inverse BiDi" algorithm, then we
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* don't need to insert any LRMs, and don't need to test for it.
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*/
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if(!ubidi_isInverse(pBiDi)) {
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options&=~UBIDI_INSERT_LRM_FOR_NUMERIC;
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}
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/*
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* Iterate through all visual runs and copy the run text segments to
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* the destination, according to the options.
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*
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* The tests for where to insert LRMs ignore the fact that there may be
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* BN codes or non-BMP code points at the beginning and end of a run;
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* they may insert LRMs unnecessarily but the tests are faster this way
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* (this would have to be improved for UTF-8).
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*/
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if(!(options&UBIDI_OUTPUT_REVERSE)) {
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/* forward output */
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if(!(options&UBIDI_INSERT_LRM_FOR_NUMERIC)) {
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/* do not insert BiDi controls */
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for(run=0; run<runCount; ++run) {
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if(UBIDI_LTR==ubidi_getVisualRun(pBiDi, run, &logicalStart, &runLength)) {
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runLength=doWriteForward(text+logicalStart, runLength,
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dest, destSize,
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(uint16_t)(options&~UBIDI_DO_MIRRORING), pErrorCode);
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} else {
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runLength=doWriteReverse(text+logicalStart, runLength,
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dest, destSize,
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options, pErrorCode);
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}
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dest+=runLength;
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destSize-=runLength;
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if(U_FAILURE(*pErrorCode)) {
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return 0;
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}
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}
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} else {
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/* insert BiDi controls for "inverse BiDi" */
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const UChar *src;
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UBiDiDirection dir;
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for(run=0; run<runCount; ++run) {
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dir=ubidi_getVisualRun(pBiDi, run, &logicalStart, &runLength);
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src=text+logicalStart;
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if(UBIDI_LTR==dir) {
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if(/*run>0 &&*/ u_charDirection(*src)!=U_LEFT_TO_RIGHT) {
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if(destSize==0) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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*dest++=LRM_CHAR;
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--destSize;
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}
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runLength=doWriteForward(src, runLength,
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dest, destSize,
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(uint16_t)(options&~UBIDI_DO_MIRRORING), pErrorCode);
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if(U_FAILURE(*pErrorCode)) {
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return 0;
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}
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dest+=runLength;
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destSize-=runLength;
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if(/*run<runCount-1 &&*/ u_charDirection(src[runLength-1])!=U_LEFT_TO_RIGHT) {
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if(destSize==0) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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*dest++=LRM_CHAR;
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--destSize;
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}
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} else {
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if(/*run>0 &&*/ !(MASK_R_AL&1UL<<u_charDirection(src[runLength-1]))) {
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if(destSize==0) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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*dest++=RLM_CHAR;
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--destSize;
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}
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runLength=doWriteReverse(src, runLength,
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dest, destSize,
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options, pErrorCode);
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if(U_FAILURE(*pErrorCode)) {
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return 0;
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}
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dest+=runLength;
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destSize-=runLength;
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if(/*run<runCount-1 &&*/ !(MASK_R_AL&1UL<<u_charDirection(*src))) {
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if(destSize==0) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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*dest++=RLM_CHAR;
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--destSize;
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}
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}
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}
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}
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} else {
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/* reverse output */
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if(!(options&UBIDI_INSERT_LRM_FOR_NUMERIC)) {
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/* do not insert BiDi controls */
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for(run=runCount; --run>=0;) {
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if(UBIDI_LTR==ubidi_getVisualRun(pBiDi, run, &logicalStart, &runLength)) {
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runLength=doWriteReverse(text+logicalStart, runLength,
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dest, destSize,
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(uint16_t)(options&~UBIDI_DO_MIRRORING), pErrorCode);
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} else {
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runLength=doWriteForward(text+logicalStart, runLength,
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dest, destSize,
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options, pErrorCode);
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}
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dest+=runLength;
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destSize-=runLength;
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if(U_FAILURE(*pErrorCode)) {
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return 0;
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}
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}
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} else {
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/* insert BiDi controls for "inverse BiDi" */
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const UChar *src;
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UBiDiDirection dir;
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for(run=runCount; --run>=0;) {
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/* reverse output */
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dir=ubidi_getVisualRun(pBiDi, run, &logicalStart, &runLength);
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src=text+logicalStart;
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if(UBIDI_LTR==dir) {
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if(/*run<runCount-1 &&*/ u_charDirection(src[runLength-1])!=U_LEFT_TO_RIGHT) {
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if(destSize==0) {
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*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
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return 0;
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}
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*dest++=LRM_CHAR;
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--destSize;
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}
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runLength=doWriteReverse(src, runLength,
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dest, destSize,
|
|
(uint16_t)(options&~UBIDI_DO_MIRRORING), pErrorCode);
|
|
if(U_FAILURE(*pErrorCode)) {
|
|
return 0;
|
|
}
|
|
dest+=runLength;
|
|
destSize-=runLength;
|
|
|
|
if(/*run>0 &&*/ u_charDirection(*src)!=U_LEFT_TO_RIGHT) {
|
|
if(destSize==0) {
|
|
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
|
|
return 0;
|
|
}
|
|
*dest++=LRM_CHAR;
|
|
--destSize;
|
|
}
|
|
} else {
|
|
if(/*run<runCount-1 &&*/ !(MASK_R_AL&1UL<<u_charDirection(*src))) {
|
|
if(destSize==0) {
|
|
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
|
|
return 0;
|
|
}
|
|
*dest++=RLM_CHAR;
|
|
--destSize;
|
|
}
|
|
|
|
runLength=doWriteForward(src, runLength,
|
|
dest, destSize,
|
|
options, pErrorCode);
|
|
if(U_FAILURE(*pErrorCode)) {
|
|
return 0;
|
|
}
|
|
dest+=runLength;
|
|
destSize-=runLength;
|
|
|
|
if(/*run>0 &&*/ !(MASK_R_AL&1UL<<u_charDirection(src[runLength-1]))) {
|
|
if(destSize==0) {
|
|
*pErrorCode=U_BUFFER_OVERFLOW_ERROR;
|
|
return 0;
|
|
}
|
|
*dest++=RLM_CHAR;
|
|
--destSize;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return dest-oldDest;
|
|
}
|