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      1 /*
      2  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
      3  *
      4  * This is part of HarfBuzz, an OpenType Layout engine library.
      5  *
      6  * Permission is hereby granted, without written agreement and without
      7  * license or royalty fees, to use, copy, modify, and distribute this
      8  * software and its documentation for any purpose, provided that the
      9  * above copyright notice and the following two paragraphs appear in
     10  * all copies of this software.
     11  *
     12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
     13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
     14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
     15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
     16  * DAMAGE.
     17  *
     18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
     19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
     20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
     21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
     22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
     23  */
     24 
     25 #include "harfbuzz-shaper.h"
     26 #include "harfbuzz-shaper-private.h"
     27 
     28 #include <assert.h>
     29 
     30 /*
     31  tibetan syllables are of the form:
     32     head position consonant
     33     first sub-joined consonant
     34     ....intermediate sub-joined consonants (if any)
     35     last sub-joined consonant
     36     sub-joined vowel (a-chung U+0F71)
     37     standard or compound vowel sign (or 'virama' for devanagari transliteration)
     38 */
     39 
     40 typedef enum {
     41     TibetanOther,
     42     TibetanHeadConsonant,
     43     TibetanSubjoinedConsonant,
     44     TibetanSubjoinedVowel,
     45     TibetanVowel
     46 } TibetanForm;
     47 
     48 /* this table starts at U+0f40 */
     49 static const unsigned char tibetanForm[0x80] = {
     50     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     51     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     52     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     53     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     54 
     55     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     56     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     57     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     58     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     59 
     60     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     61     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     62     TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant, TibetanHeadConsonant,
     63     TibetanOther, TibetanOther, TibetanOther, TibetanOther,
     64 
     65     TibetanOther, TibetanVowel, TibetanVowel, TibetanVowel,
     66     TibetanVowel, TibetanVowel, TibetanVowel, TibetanVowel,
     67     TibetanVowel, TibetanVowel, TibetanVowel, TibetanVowel,
     68     TibetanVowel, TibetanVowel, TibetanVowel, TibetanVowel,
     69 
     70     TibetanVowel, TibetanVowel, TibetanVowel, TibetanVowel,
     71     TibetanVowel, TibetanVowel, TibetanVowel, TibetanVowel,
     72     TibetanOther, TibetanOther, TibetanOther, TibetanOther,
     73     TibetanOther, TibetanOther, TibetanOther, TibetanOther,
     74 
     75     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     76     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     77     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     78     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     79 
     80     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     81     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     82     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     83     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     84 
     85     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     86     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     87     TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant, TibetanSubjoinedConsonant,
     88     TibetanSubjoinedConsonant, TibetanOther, TibetanOther, TibetanOther
     89 };
     90 
     91 
     92 #define tibetan_form(c) \
     93     ((c) >= 0x0f40 && (c) < 0x0fc0 ? (TibetanForm)tibetanForm[(c) - 0x0f40] : TibetanOther)
     94 
     95 static const HB_OpenTypeFeature tibetan_features[] = {
     96     { HB_MAKE_TAG('c', 'c', 'm', 'p'), CcmpProperty },
     97     { HB_MAKE_TAG('a', 'b', 'v', 's'), AboveSubstProperty },
     98     { HB_MAKE_TAG('b', 'l', 'w', 's'), BelowSubstProperty },
     99     { HB_MAKE_TAG('c', 'a', 'l', 't'), CaltProperty },
    100     {0, 0}
    101 };
    102 
    103 static HB_Bool tibetan_shape_syllable(HB_Bool openType, HB_ShaperItem *item, HB_Bool invalid)
    104 {
    105     hb_uint32 i;
    106     const HB_UChar16 *str = item->string + item->item.pos;
    107     int len = item->item.length;
    108 #ifndef NO_OPENTYPE
    109     const int availableGlyphs = item->num_glyphs;
    110 #endif
    111     HB_Bool haveGlyphs;
    112     HB_STACKARRAY(HB_UChar16, reordered, len + 4);
    113 
    114     if (item->num_glyphs < item->item.length + 4) {
    115         item->num_glyphs = item->item.length + 4;
    116         HB_FREE_STACKARRAY(reordered);
    117         return FALSE;
    118     }
    119 
    120     if (invalid) {
    121         *reordered = 0x25cc;
    122         memcpy(reordered+1, str, len*sizeof(HB_UChar16));
    123         len++;
    124         str = reordered;
    125     }
    126 
    127     haveGlyphs = item->font->klass->convertStringToGlyphIndices(item->font,
    128                                                                 str, len,
    129                                                                 item->glyphs, &item->num_glyphs,
    130                                                                 item->item.bidiLevel % 2);
    131 
    132     HB_FREE_STACKARRAY(reordered);
    133 
    134     if (!haveGlyphs)
    135         return FALSE;
    136 
    137     for (i = 0; i < item->item.length; i++) {
    138         item->attributes[i].mark = FALSE;
    139         item->attributes[i].clusterStart = FALSE;
    140         item->attributes[i].justification = 0;
    141         item->attributes[i].zeroWidth = FALSE;
    142 /*        IDEBUG("    %d: %4x", i, str[i]); */
    143     }
    144 
    145     /* now we have the syllable in the right order, and can start running it through open type. */
    146 
    147 #ifndef NO_OPENTYPE
    148     if (openType) {
    149         HB_OpenTypeShape(item, /*properties*/0);
    150         if (!HB_OpenTypePosition(item, availableGlyphs, /*doLogClusters*/FALSE))
    151             return FALSE;
    152     } else {
    153         HB_HeuristicPosition(item);
    154     }
    155 #endif
    156 
    157     item->attributes[0].clusterStart = TRUE;
    158     return TRUE;
    159 }
    160 
    161 
    162 static int tibetan_nextSyllableBoundary(const HB_UChar16 *s, int start, int end, HB_Bool *invalid)
    163 {
    164     const HB_UChar16 *uc = s + start;
    165 
    166     int pos = 0;
    167     TibetanForm state = tibetan_form(*uc);
    168 
    169 /*     qDebug("state[%d]=%d (uc=%4x)", pos, state, uc[pos]);*/
    170     pos++;
    171 
    172     if (state != TibetanHeadConsonant) {
    173         if (state != TibetanOther)
    174             *invalid = TRUE;
    175         goto finish;
    176     }
    177 
    178     while (pos < end - start) {
    179         TibetanForm newState = tibetan_form(uc[pos]);
    180         switch(newState) {
    181         case TibetanSubjoinedConsonant:
    182         case TibetanSubjoinedVowel:
    183             if (state != TibetanHeadConsonant &&
    184                  state != TibetanSubjoinedConsonant)
    185                 goto finish;
    186             state = newState;
    187             break;
    188         case TibetanVowel:
    189             if (state != TibetanHeadConsonant &&
    190                  state != TibetanSubjoinedConsonant &&
    191                  state != TibetanSubjoinedVowel)
    192                 goto finish;
    193             break;
    194         case TibetanOther:
    195         case TibetanHeadConsonant:
    196             goto finish;
    197         }
    198         pos++;
    199     }
    200 
    201 finish:
    202     *invalid = FALSE;
    203     return start+pos;
    204 }
    205 
    206 HB_Bool HB_TibetanShape(HB_ShaperItem *item)
    207 {
    208 
    209     HB_Bool openType = FALSE;
    210     unsigned short *logClusters = item->log_clusters;
    211 
    212     HB_ShaperItem syllable = *item;
    213     int first_glyph = 0;
    214 
    215     int sstart = item->item.pos;
    216     int end = sstart + item->item.length;
    217 
    218     assert(item->item.script == HB_Script_Tibetan);
    219 
    220 #ifndef QT_NO_OPENTYPE
    221     openType = HB_SelectScript(item, tibetan_features);
    222 #endif
    223 
    224     while (sstart < end) {
    225         HB_Bool invalid;
    226         int i;
    227         int send = tibetan_nextSyllableBoundary(item->string, sstart, end, &invalid);
    228 /*        IDEBUG("syllable from %d, length %d, invalid=%s", sstart, send-sstart,
    229                  invalid ? "TRUE" : "FALSE"); */
    230         syllable.item.pos = sstart;
    231         syllable.item.length = send-sstart;
    232         syllable.glyphs = item->glyphs + first_glyph;
    233         syllable.attributes = item->attributes + first_glyph;
    234         syllable.offsets = item->offsets + first_glyph;
    235         syllable.advances = item->advances + first_glyph;
    236         syllable.num_glyphs = item->num_glyphs - first_glyph;
    237         if (!tibetan_shape_syllable(openType, &syllable, invalid)) {
    238             item->num_glyphs += syllable.num_glyphs;
    239             return FALSE;
    240         }
    241         /* fix logcluster array */
    242         for (i = sstart; i < send; ++i)
    243             logClusters[i-item->item.pos] = first_glyph;
    244         sstart = send;
    245         first_glyph += syllable.num_glyphs;
    246     }
    247     item->num_glyphs = first_glyph;
    248     return TRUE;
    249 }
    250