1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 // This file is available under and governed by the GNU General Public
26 // License version 2 only, as published by the Free Software Foundation.
27 // However, the following notice accompanied the original version of this
28 // file:
29 //
30 /*
31 * Copyright © 2009 Red Hat, Inc.
32 * Copyright © 2012 Google, Inc.
33 *
34 * This is part of HarfBuzz, a text shaping library.
35 *
36 * Permission is hereby granted, without written agreement and without
37 * license or royalty fees, to use, copy, modify, and distribute this
38 * software and its documentation for any purpose, provided that the
39 * above copyright notice and the following two paragraphs appear in
40 * all copies of this software.
41 *
42 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
43 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
44 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
45 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
46 * DAMAGE.
47 *
48 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
49 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
50 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
51 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
52 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
53 *
54 * Red Hat Author(s): Behdad Esfahbod
55 * Google Author(s): Behdad Esfahbod
56 */
57
58 #include "hb-private.hh"
59
60 #include "hb-shaper-private.hh"
61 #include "hb-shape-plan-private.hh"
62 #include "hb-buffer-private.hh"
63 #include "hb-font-private.hh"
64
65 /**
66 * SECTION:hb-shape
67 * @title: Shaping
68 * @short_description: Conversion of text strings into positioned glyphs
69 * @include: hb.h
70 *
71 * Shaping is the central operation of HarfBuzz. Shaping operates on buffers,
72 * which are sequences of Unicode characters that use the same font and have
73 * the same text direction, script and language. After shaping the buffer
74 * contains the output glyphs and their positions.
75 **/
76
77 static bool
78 parse_space (const char **pp, const char *end)
79 {
80 while (*pp < end && ISSPACE (**pp))
81 (*pp)++;
82 return true;
83 }
84
85 static bool
86 parse_char (const char **pp, const char *end, char c)
87 {
88 parse_space (pp, end);
89
90 if (*pp == end || **pp != c)
91 return false;
92
93 (*pp)++;
94 return true;
95 }
96
97 static bool
98 parse_uint (const char **pp, const char *end, unsigned int *pv)
99 {
100 char buf[32];
101 unsigned int len = MIN (ARRAY_LENGTH (buf) - 1, (unsigned int) (end - *pp));
102 strncpy (buf, *pp, len);
103 buf[len] = '\0';
104
105 char *p = buf;
106 char *pend = p;
107 unsigned int v;
108
109 /* Intentionally use strtol instead of strtoul, such that
110 * -1 turns into "big number"... */
111 errno = 0;
112 v = strtol (p, &pend, 0);
113 if (errno || p == pend)
114 return false;
115
116 *pv = v;
117 *pp += pend - p;
118 return true;
119 }
120
121 static bool
122 parse_bool (const char **pp, const char *end, unsigned int *pv)
123 {
124 parse_space (pp, end);
125
126 const char *p = *pp;
127 while (*pp < end && ISALPHA(**pp))
128 (*pp)++;
129
130 /* CSS allows on/off as aliases 1/0. */
131 if (*pp - p == 2 || 0 == strncmp (p, "on", 2))
132 *pv = 1;
133 else if (*pp - p == 3 || 0 == strncmp (p, "off", 2))
134 *pv = 0;
135 else
136 return false;
137
138 return true;
139 }
140
141 static bool
142 parse_feature_value_prefix (const char **pp, const char *end, hb_feature_t *feature)
143 {
144 if (parse_char (pp, end, '-'))
145 feature->value = 0;
146 else {
147 parse_char (pp, end, '+');
148 feature->value = 1;
149 }
150
151 return true;
152 }
153
154 static bool
155 parse_feature_tag (const char **pp, const char *end, hb_feature_t *feature)
156 {
157 parse_space (pp, end);
158
159 char quote = 0;
160
161 if (*pp < end && (**pp == '\'' || **pp == '"'))
162 {
163 quote = **pp;
164 (*pp)++;
165 }
166
167 const char *p = *pp;
168 while (*pp < end && ISALNUM(**pp))
169 (*pp)++;
170
171 if (p == *pp || *pp - p > 4)
172 return false;
173
174 feature->tag = hb_tag_from_string (p, *pp - p);
175
176 if (quote)
177 {
178 /* CSS expects exactly four bytes. And we only allow quotations for
179 * CSS compatibility. So, enforce the length. */
180 if (*pp - p != 4)
181 return false;
182 if (*pp == end || **pp != quote)
183 return false;
184 (*pp)++;
185 }
186
187 return true;
188 }
189
190 static bool
191 parse_feature_indices (const char **pp, const char *end, hb_feature_t *feature)
192 {
193 parse_space (pp, end);
194
195 bool has_start;
196
197 feature->start = 0;
198 feature->end = (unsigned int) -1;
199
200 if (!parse_char (pp, end, '['))
201 return true;
202
203 has_start = parse_uint (pp, end, &feature->start);
204
205 if (parse_char (pp, end, ':')) {
206 parse_uint (pp, end, &feature->end);
207 } else {
208 if (has_start)
209 feature->end = feature->start + 1;
210 }
211
212 return parse_char (pp, end, ']');
213 }
214
215 static bool
216 parse_feature_value_postfix (const char **pp, const char *end, hb_feature_t *feature)
217 {
218 bool had_equal = parse_char (pp, end, '=');
219 bool had_value = parse_uint (pp, end, &feature->value) ||
220 parse_bool (pp, end, &feature->value);
221 /* CSS doesn't use equal-sign between tag and value.
222 * If there was an equal-sign, then there *must* be a value.
223 * A value without an eqaul-sign is ok, but not required. */
224 return !had_equal || had_value;
225 }
226
227
228 static bool
229 parse_one_feature (const char **pp, const char *end, hb_feature_t *feature)
230 {
231 return parse_feature_value_prefix (pp, end, feature) &&
232 parse_feature_tag (pp, end, feature) &&
233 parse_feature_indices (pp, end, feature) &&
234 parse_feature_value_postfix (pp, end, feature) &&
235 parse_space (pp, end) &&
236 *pp == end;
237 }
238
239 /**
240 * hb_feature_from_string:
241 * @str: (array length=len) (element-type uint8_t): a string to parse
242 * @len: length of @str, or -1 if string is nul-terminated
243 * @feature: (out): the #hb_feature_t to initialize with the parsed values
244 *
245 * Parses a string into a #hb_feature_t. If @len is -1 then @str is
246 * %NULL-terminated.
247 *
248 * Return value: %TRUE if @str is successfully parsed, %FALSE otherwise
249 *
250 * Since: 0.9.5
251 **/
252 hb_bool_t
253 hb_feature_from_string (const char *str, int len,
254 hb_feature_t *feature)
255 {
256 hb_feature_t feat;
257
258 if (len < 0)
259 len = strlen (str);
260
261 if (likely (parse_one_feature (&str, str + len, &feat)))
262 {
263 if (feature)
264 *feature = feat;
265 return true;
266 }
267
268 if (feature)
269 memset (feature, 0, sizeof (*feature));
270 return false;
271 }
272
273 /**
274 * hb_feature_to_string:
275 * @feature: an #hb_feature_t to convert
276 * @buf: (array length=size) (out): output string
277 * @size: the allocated size of @buf
278 *
279 * Converts a #hb_feature_t into a %NULL-terminated string in the format
280 * understood by hb_feature_from_string(). The client in responsible for
281 * allocating big enough size for @buf, 128 bytes is more than enough.
282 *
283 * Since: 0.9.5
284 **/
285 void
286 hb_feature_to_string (hb_feature_t *feature,
287 char *buf, unsigned int size)
288 {
289 if (unlikely (!size)) return;
290
291 char s[128];
292 unsigned int len = 0;
293 if (feature->value == 0)
294 s[len++] = '-';
295 hb_tag_to_string (feature->tag, s + len);
296 len += 4;
297 while (len && s[len - 1] == ' ')
298 len--;
299 if (feature->start != 0 || feature->end != (unsigned int) -1)
300 {
301 s[len++] = '[';
302 if (feature->start)
303 len += MAX (0, snprintf (s + len, ARRAY_LENGTH (s) - len, "%u", feature->start));
304 if (feature->end != feature->start + 1) {
305 s[len++] = ':';
306 if (feature->end != (unsigned int) -1)
307 len += MAX (0, snprintf (s + len, ARRAY_LENGTH (s) - len, "%u", feature->end));
308 }
309 s[len++] = ']';
310 }
311 if (feature->value > 1)
312 {
313 s[len++] = '=';
314 len += MAX (0, snprintf (s + len, ARRAY_LENGTH (s) - len, "%u", feature->value));
315 }
316 assert (len < ARRAY_LENGTH (s));
317 len = MIN (len, size - 1);
318 memcpy (buf, s, len);
319 buf[len] = '\0';
320 }
321
322
323 static const char **static_shaper_list;
324
325 #ifdef HB_USE_ATEXIT
326 static
327 void free_static_shaper_list (void)
328 {
329 free (static_shaper_list);
330 }
331 #endif
332
333 /**
334 * hb_shape_list_shapers:
335 *
336 * Retrieves the list of shapers supported by HarfBuzz.
337 *
338 * Return value: (transfer none) (array zero-terminated=1): an array of
339 * constant strings
340 *
341 * Since: 0.9.2
342 **/
343 const char **
344 hb_shape_list_shapers (void)
345 {
346 retry:
347 const char **shaper_list = (const char **) hb_atomic_ptr_get (&static_shaper_list);
348
349 if (unlikely (!shaper_list))
350 {
351 /* Not found; allocate one. */
352 shaper_list = (const char **) calloc (1 + HB_SHAPERS_COUNT, sizeof (const char *));
353 if (unlikely (!shaper_list)) {
354 static const char *nil_shaper_list[] = {NULL};
355 return nil_shaper_list;
356 }
357
358 const hb_shaper_pair_t *shapers = _hb_shapers_get ();
359 unsigned int i;
360 for (i = 0; i < HB_SHAPERS_COUNT; i++)
361 shaper_list[i] = shapers[i].name;
362 shaper_list[i] = NULL;
363
364 if (!hb_atomic_ptr_cmpexch (&static_shaper_list, NULL, shaper_list)) {
365 free (shaper_list);
366 goto retry;
367 }
368
369 #ifdef HB_USE_ATEXIT
370 atexit (free_static_shaper_list); /* First person registers atexit() callback. */
371 #endif
372 }
373
374 return shaper_list;
375 }
376
377
378 /**
379 * hb_shape_full:
380 * @font: an #hb_font_t to use for shaping
381 * @buffer: an #hb_buffer_t to shape
382 * @features: (array length=num_features) (allow-none): an array of user
383 * specified #hb_feature_t or %NULL
384 * @num_features: the length of @features array
385 * @shaper_list: (array zero-terminated=1) (allow-none): a %NULL-terminated
386 * array of shapers to use or %NULL
387 *
388 * See hb_shape() for details. If @shaper_list is not %NULL, the specified
389 * shapers will be used in the given order, otherwise the default shapers list
390 * will be used.
391 *
392 * Return value: %FALSE if all shapers failed, %TRUE otherwise
393 *
394 * Since: 0.9.2
395 **/
396 hb_bool_t
397 hb_shape_full (hb_font_t *font,
398 hb_buffer_t *buffer,
399 const hb_feature_t *features,
400 unsigned int num_features,
401 const char * const *shaper_list)
402 {
403 hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached (font->face, &buffer->props, features, num_features, shaper_list);
404 hb_bool_t res = hb_shape_plan_execute (shape_plan, font, buffer, features, num_features);
405 hb_shape_plan_destroy (shape_plan);
406
407 if (res)
408 buffer->content_type = HB_BUFFER_CONTENT_TYPE_GLYPHS;
409 return res;
410 }
411
412 /**
413 * hb_shape:
414 * @font: an #hb_font_t to use for shaping
415 * @buffer: an #hb_buffer_t to shape
416 * @features: (array length=num_features) (allow-none): an array of user
417 * specified #hb_feature_t or %NULL
418 * @num_features: the length of @features array
419 *
420 * Shapes @buffer using @font turning its Unicode characters content to
421 * positioned glyphs. If @features is not %NULL, it will be used to control the
422 * features applied during shaping.
423 *
424 * Return value: %FALSE if all shapers failed, %TRUE otherwise
425 *
426 * Since: 0.9.2
427 **/
428 void
429 hb_shape (hb_font_t *font,
430 hb_buffer_t *buffer,
431 const hb_feature_t *features,
432 unsigned int num_features)
433 {
434 hb_shape_full (font, buffer, features, num_features, NULL);
435 }