Check in the pristine copy of ICU 4.6...

icu46/source/common/ubidiwrt.c

+/*
+******************************************************************************
+*
+*   Copyright (C) 2000-2007, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+******************************************************************************
+*   file name:  ubidiwrt.c
+*   encoding:   US-ASCII
+*   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.
+*/
+
+/* set import/export definitions */
+#ifndef U_COMMON_IMPLEMENTATION
+#   define U_COMMON_IMPLEMENTATION
+#endif
+
+#include "unicode/utypes.h"
+#include "unicode/ustring.h"
+#include "unicode/uchar.h"
+#include "unicode/ubidi.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 {
+            UTF_NEXT_CHAR(src, i, srcLength, c);
+            c=u_charMirror(c);
+            UTF_APPEND_CHAR_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;
+            UTF_NEXT_CHAR(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);
+                UTF_APPEND_CHAR_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 */
+            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;
+}
+
+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);
+                }
+                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);
+                    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);
+                    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);
+                }
+                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);
+                    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);
+                    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);
+}