1 /*
2  * Copyright (C) 2015 The Qt Company Ltd
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 #ifndef NO_OPENTYPE
96 static const HB_OpenTypeFeature tibetan_features[] = {
97     { HB_MAKE_TAG('c', 'c', 'm', 'p'), CcmpProperty },
98     { HB_MAKE_TAG('a', 'b', 'v', 's'), AboveSubstProperty },
99     { HB_MAKE_TAG('b', 'l', 'w', 's'), BelowSubstProperty },
100     { HB_MAKE_TAG('c', 'a', 'l', 't'), CaltProperty },
101     {0, 0}
102 };
103 #endif
104 
tibetan_shape_syllable(HB_Bool openType,HB_ShaperItem * item,HB_Bool invalid)105 static HB_Bool tibetan_shape_syllable(HB_Bool openType, HB_ShaperItem *item, HB_Bool invalid)
106 {
107     hb_uint32 i;
108     const HB_UChar16 *str = item->string + item->item.pos;
109     int len = item->item.length;
110 #ifndef NO_OPENTYPE
111     const int availableGlyphs = item->num_glyphs;
112 #endif
113     HB_Bool haveGlyphs;
114     HB_STACKARRAY(HB_UChar16, reordered, len + 4);
115 
116     if (item->num_glyphs < item->item.length + 4) {
117         item->num_glyphs = item->item.length + 4;
118         HB_FREE_STACKARRAY(reordered);
119         return FALSE;
120     }
121 
122     if (invalid) {
123         *reordered = 0x25cc;
124         memcpy(reordered+1, str, len*sizeof(HB_UChar16));
125         len++;
126         str = reordered;
127     }
128 
129     haveGlyphs = item->font->klass->convertStringToGlyphIndices(item->font,
130                                                                 str, len,
131                                                                 item->glyphs, &item->num_glyphs,
132                                                                 item->item.bidiLevel % 2);
133 
134     HB_FREE_STACKARRAY(reordered);
135 
136     if (!haveGlyphs)
137         return FALSE;
138 
139     for (i = 0; i < item->item.length; i++) {
140         item->attributes[i].mark = FALSE;
141         item->attributes[i].clusterStart = FALSE;
142         item->attributes[i].justification = 0;
143         item->attributes[i].zeroWidth = FALSE;
144 /*        IDEBUG("    %d: %4x", i, str[i]); */
145     }
146 
147     /* now we have the syllable in the right order, and can start running it through open type. */
148 
149 #ifndef NO_OPENTYPE
150     if (openType) {
151         HB_OpenTypeShape(item, /*properties*/0);
152         if (!HB_OpenTypePosition(item, availableGlyphs, /*doLogClusters*/FALSE))
153             return FALSE;
154     } else {
155         HB_HeuristicPosition(item);
156     }
157 #endif
158 
159     item->attributes[0].clusterStart = TRUE;
160     return TRUE;
161 }
162 
163 
tibetan_nextSyllableBoundary(const HB_UChar16 * s,int start,int end,HB_Bool * invalid)164 static int tibetan_nextSyllableBoundary(const HB_UChar16 *s, int start, int end, HB_Bool *invalid)
165 {
166     const HB_UChar16 *uc = s + start;
167 
168     int pos = 0;
169     TibetanForm state = tibetan_form(*uc);
170 
171 /*     qDebug("state[%d]=%d (uc=%4x)", pos, state, uc[pos]);*/
172     pos++;
173 
174     if (state != TibetanHeadConsonant) {
175         if (state != TibetanOther)
176             *invalid = TRUE;
177         goto finish;
178     }
179 
180     while (pos < end - start) {
181         TibetanForm newState = tibetan_form(uc[pos]);
182         switch(newState) {
183         case TibetanSubjoinedConsonant:
184         case TibetanSubjoinedVowel:
185             if (state != TibetanHeadConsonant &&
186                  state != TibetanSubjoinedConsonant)
187                 goto finish;
188             state = newState;
189             break;
190         case TibetanVowel:
191             if (state != TibetanHeadConsonant &&
192                  state != TibetanSubjoinedConsonant &&
193                  state != TibetanSubjoinedVowel)
194                 goto finish;
195             break;
196         case TibetanOther:
197         case TibetanHeadConsonant:
198             goto finish;
199         }
200         pos++;
201     }
202 
203 finish:
204     *invalid = FALSE;
205     return start+pos;
206 }
207 
HB_TibetanShape(HB_ShaperItem * item)208 HB_Bool HB_TibetanShape(HB_ShaperItem *item)
209 {
210 
211     HB_Bool openType = FALSE;
212     unsigned short *logClusters = item->log_clusters;
213 
214     HB_ShaperItem syllable = *item;
215     int first_glyph = 0;
216 
217     int sstart = item->item.pos;
218     int end = sstart + item->item.length;
219 
220     assert(item->item.script == HB_Script_Tibetan);
221 
222 #ifndef NO_OPENTYPE
223     openType = HB_SelectScript(item, tibetan_features);
224 #endif
225 
226     while (sstart < end) {
227         HB_Bool invalid;
228         int i;
229         int send = tibetan_nextSyllableBoundary(item->string, sstart, end, &invalid);
230 /*        IDEBUG("syllable from %d, length %d, invalid=%s", sstart, send-sstart,
231                  invalid ? "TRUE" : "FALSE"); */
232         syllable.item.pos = sstart;
233         syllable.item.length = send-sstart;
234         syllable.glyphs = item->glyphs + first_glyph;
235         syllable.attributes = item->attributes + first_glyph;
236         syllable.offsets = item->offsets + first_glyph;
237         syllable.advances = item->advances + first_glyph;
238         syllable.num_glyphs = item->num_glyphs - first_glyph;
239         if (!tibetan_shape_syllable(openType, &syllable, invalid)) {
240             item->num_glyphs += syllable.num_glyphs;
241             return FALSE;
242         }
243         /* fix logcluster array */
244         for (i = sstart; i < send; ++i)
245             logClusters[i-item->item.pos] = first_glyph;
246         sstart = send;
247         first_glyph += syllable.num_glyphs;
248     }
249     item->num_glyphs = first_glyph;
250     return TRUE;
251 }
252 
HB_TibetanAttributes(HB_Script script,const HB_UChar16 * text,hb_uint32 from,hb_uint32 len,HB_CharAttributes * attributes)253 void HB_TibetanAttributes(HB_Script script, const HB_UChar16 *text, hb_uint32 from, hb_uint32 len, HB_CharAttributes *attributes)
254 {
255     int end = from + len;
256     const HB_UChar16 *uc = text + from;
257     hb_uint32 i = 0;
258     HB_UNUSED(script);
259     attributes += from;
260     while (i < len) {
261         HB_Bool invalid;
262         hb_uint32 boundary = tibetan_nextSyllableBoundary(text, from+i, end, &invalid) - from;
263 
264         attributes[i].graphemeBoundary = TRUE;
265 
266         if (boundary > len-1) boundary = len;
267         i++;
268         while (i < boundary) {
269             attributes[i].graphemeBoundary = FALSE;
270             ++uc;
271             ++i;
272         }
273         assert(i == boundary);
274     }
275 }
276 
277 
278