1 /*
2 * Copyright © 2011,2012,2014 Google, Inc.
3 *
4 * This is part of HarfBuzz, a text shaping 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 * Google Author(s): Behdad Esfahbod
25 */
26
27 #ifndef HB_UTF_HH
28 #define HB_UTF_HH
29
30 #include "hb.hh"
31
32 #include "hb-open-type.hh"
33
34
35 struct hb_utf8_t
36 {
37 typedef uint8_t codepoint_t;
38 static constexpr unsigned max_len = 4;
39
40 static const codepoint_t *
nexthb_utf8_t41 next (const codepoint_t *text,
42 const codepoint_t *end,
43 hb_codepoint_t *unicode,
44 hb_codepoint_t replacement)
45 {
46 /* Written to only accept well-formed sequences.
47 * Based on ideas from ICU's U8_NEXT.
48 * Generates one "replacement" for each ill-formed byte. */
49
50 hb_codepoint_t c = *text++;
51
52 if (c > 0x7Fu)
53 {
54 if (hb_in_range<hb_codepoint_t> (c, 0xC2u, 0xDFu)) /* Two-byte */
55 {
56 unsigned int t1;
57 if (likely (text < end &&
58 (t1 = text[0] - 0x80u) <= 0x3Fu))
59 {
60 c = ((c&0x1Fu)<<6) | t1;
61 text++;
62 }
63 else
64 goto error;
65 }
66 else if (hb_in_range<hb_codepoint_t> (c, 0xE0u, 0xEFu)) /* Three-byte */
67 {
68 unsigned int t1, t2;
69 if (likely (1 < end - text &&
70 (t1 = text[0] - 0x80u) <= 0x3Fu &&
71 (t2 = text[1] - 0x80u) <= 0x3Fu))
72 {
73 c = ((c&0xFu)<<12) | (t1<<6) | t2;
74 if (unlikely (c < 0x0800u || hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
75 goto error;
76 text += 2;
77 }
78 else
79 goto error;
80 }
81 else if (hb_in_range<hb_codepoint_t> (c, 0xF0u, 0xF4u)) /* Four-byte */
82 {
83 unsigned int t1, t2, t3;
84 if (likely (2 < end - text &&
85 (t1 = text[0] - 0x80u) <= 0x3Fu &&
86 (t2 = text[1] - 0x80u) <= 0x3Fu &&
87 (t3 = text[2] - 0x80u) <= 0x3Fu))
88 {
89 c = ((c&0x7u)<<18) | (t1<<12) | (t2<<6) | t3;
90 if (unlikely (!hb_in_range<hb_codepoint_t> (c, 0x10000u, 0x10FFFFu)))
91 goto error;
92 text += 3;
93 }
94 else
95 goto error;
96 }
97 else
98 goto error;
99 }
100
101 *unicode = c;
102 return text;
103
104 error:
105 *unicode = replacement;
106 return text;
107 }
108
109 static const codepoint_t *
prevhb_utf8_t110 prev (const codepoint_t *text,
111 const codepoint_t *start,
112 hb_codepoint_t *unicode,
113 hb_codepoint_t replacement)
114 {
115 const codepoint_t *end = text--;
116 while (start < text && (*text & 0xc0) == 0x80 && end - text < 4)
117 text--;
118
119 if (likely (next (text, end, unicode, replacement) == end))
120 return text;
121
122 *unicode = replacement;
123 return end - 1;
124 }
125
126 static unsigned int
strlenhb_utf8_t127 strlen (const codepoint_t *text)
128 { return ::strlen ((const char *) text); }
129
130 static unsigned int
encode_lenhb_utf8_t131 encode_len (hb_codepoint_t unicode)
132 {
133 if (unicode < 0x0080u) return 1;
134 if (unicode < 0x0800u) return 2;
135 if (unicode < 0x10000u) return 3;
136 if (unicode < 0x110000u) return 4;
137 return 3;
138 }
139
140 static codepoint_t *
encodehb_utf8_t141 encode (codepoint_t *text,
142 const codepoint_t *end,
143 hb_codepoint_t unicode)
144 {
145 if (unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
146 unicode = 0xFFFDu;
147 if (unicode < 0x0080u)
148 *text++ = unicode;
149 else if (unicode < 0x0800u)
150 {
151 if (end - text >= 2)
152 {
153 *text++ = 0xC0u + (0x1Fu & (unicode >> 6));
154 *text++ = 0x80u + (0x3Fu & (unicode ));
155 }
156 }
157 else if (unicode < 0x10000u)
158 {
159 if (end - text >= 3)
160 {
161 *text++ = 0xE0u + (0x0Fu & (unicode >> 12));
162 *text++ = 0x80u + (0x3Fu & (unicode >> 6));
163 *text++ = 0x80u + (0x3Fu & (unicode ));
164 }
165 }
166 else
167 {
168 if (end - text >= 4)
169 {
170 *text++ = 0xF0u + (0x07u & (unicode >> 18));
171 *text++ = 0x80u + (0x3Fu & (unicode >> 12));
172 *text++ = 0x80u + (0x3Fu & (unicode >> 6));
173 *text++ = 0x80u + (0x3Fu & (unicode ));
174 }
175 }
176 return text;
177 }
178 };
179
180
181 template <typename TCodepoint>
182 struct hb_utf16_xe_t
183 {
184 static_assert (sizeof (TCodepoint) == 2, "");
185 typedef TCodepoint codepoint_t;
186 static constexpr unsigned max_len = 2;
187
188 static const codepoint_t *
nexthb_utf16_xe_t189 next (const codepoint_t *text,
190 const codepoint_t *end,
191 hb_codepoint_t *unicode,
192 hb_codepoint_t replacement)
193 {
194 hb_codepoint_t c = *text++;
195
196 if (likely (!hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
197 {
198 *unicode = c;
199 return text;
200 }
201
202 if (likely (c <= 0xDBFFu && text < end))
203 {
204 /* High-surrogate in c */
205 hb_codepoint_t l = *text;
206 if (likely (hb_in_range<hb_codepoint_t> (l, 0xDC00u, 0xDFFFu)))
207 {
208 /* Low-surrogate in l */
209 *unicode = (c << 10) + l - ((0xD800u << 10) - 0x10000u + 0xDC00u);
210 text++;
211 return text;
212 }
213 }
214
215 /* Lonely / out-of-order surrogate. */
216 *unicode = replacement;
217 return text;
218 }
219
220 static const codepoint_t *
prevhb_utf16_xe_t221 prev (const codepoint_t *text,
222 const codepoint_t *start,
223 hb_codepoint_t *unicode,
224 hb_codepoint_t replacement)
225 {
226 hb_codepoint_t c = *--text;
227
228 if (likely (!hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
229 {
230 *unicode = c;
231 return text;
232 }
233
234 if (likely (c >= 0xDC00u && start < text))
235 {
236 /* Low-surrogate in c */
237 hb_codepoint_t h = text[-1];
238 if (likely (hb_in_range<hb_codepoint_t> (h, 0xD800u, 0xDBFFu)))
239 {
240 /* High-surrogate in h */
241 *unicode = (h << 10) + c - ((0xD800u << 10) - 0x10000u + 0xDC00u);
242 text--;
243 return text;
244 }
245 }
246
247 /* Lonely / out-of-order surrogate. */
248 *unicode = replacement;
249 return text;
250 }
251
252
253 static unsigned int
strlenhb_utf16_xe_t254 strlen (const codepoint_t *text)
255 {
256 unsigned int l = 0;
257 while (*text++) l++;
258 return l;
259 }
260
261 static unsigned int
encode_lenhb_utf16_xe_t262 encode_len (hb_codepoint_t unicode)
263 {
264 return unicode < 0x10000 ? 1 : 2;
265 }
266
267 static codepoint_t *
encodehb_utf16_xe_t268 encode (codepoint_t *text,
269 const codepoint_t *end,
270 hb_codepoint_t unicode)
271 {
272 if (unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
273 unicode = 0xFFFDu;
274 if (unicode < 0x10000u)
275 *text++ = unicode;
276 else if (end - text >= 2)
277 {
278 unicode -= 0x10000u;
279 *text++ = 0xD800u + (unicode >> 10);
280 *text++ = 0xDC00u + (unicode & 0x03FFu);
281 }
282 return text;
283 }
284 };
285
286 typedef hb_utf16_xe_t<uint16_t> hb_utf16_t;
287 typedef hb_utf16_xe_t<OT::HBUINT16> hb_utf16_be_t;
288
289
290 template <typename TCodepoint, bool validate=true>
291 struct hb_utf32_xe_t
292 {
293 static_assert (sizeof (TCodepoint) == 4, "");
294 typedef TCodepoint codepoint_t;
295 static constexpr unsigned max_len = 1;
296
297 static const TCodepoint *
nexthb_utf32_xe_t298 next (const TCodepoint *text,
299 const TCodepoint *end HB_UNUSED,
300 hb_codepoint_t *unicode,
301 hb_codepoint_t replacement)
302 {
303 hb_codepoint_t c = *unicode = *text++;
304 if (validate && unlikely (c >= 0xD800u && (c <= 0xDFFFu || c > 0x10FFFFu)))
305 *unicode = replacement;
306 return text;
307 }
308
309 static const TCodepoint *
prevhb_utf32_xe_t310 prev (const TCodepoint *text,
311 const TCodepoint *start HB_UNUSED,
312 hb_codepoint_t *unicode,
313 hb_codepoint_t replacement)
314 {
315 hb_codepoint_t c = *unicode = *--text;
316 if (validate && unlikely (c >= 0xD800u && (c <= 0xDFFFu || c > 0x10FFFFu)))
317 *unicode = replacement;
318 return text;
319 }
320
321 static unsigned int
strlenhb_utf32_xe_t322 strlen (const TCodepoint *text)
323 {
324 unsigned int l = 0;
325 while (*text++) l++;
326 return l;
327 }
328
329 static unsigned int
encode_lenhb_utf32_xe_t330 encode_len (hb_codepoint_t unicode HB_UNUSED)
331 {
332 return 1;
333 }
334
335 static codepoint_t *
encodehb_utf32_xe_t336 encode (codepoint_t *text,
337 const codepoint_t *end HB_UNUSED,
338 hb_codepoint_t unicode)
339 {
340 if (validate && unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
341 unicode = 0xFFFDu;
342 *text++ = unicode;
343 return text;
344 }
345 };
346
347 typedef hb_utf32_xe_t<uint32_t> hb_utf32_t;
348 typedef hb_utf32_xe_t<uint32_t, false> hb_utf32_novalidate_t;
349
350
351 struct hb_latin1_t
352 {
353 typedef uint8_t codepoint_t;
354 static constexpr unsigned max_len = 1;
355
356 static const codepoint_t *
nexthb_latin1_t357 next (const codepoint_t *text,
358 const codepoint_t *end HB_UNUSED,
359 hb_codepoint_t *unicode,
360 hb_codepoint_t replacement HB_UNUSED)
361 {
362 *unicode = *text++;
363 return text;
364 }
365
366 static const codepoint_t *
prevhb_latin1_t367 prev (const codepoint_t *text,
368 const codepoint_t *start HB_UNUSED,
369 hb_codepoint_t *unicode,
370 hb_codepoint_t replacement HB_UNUSED)
371 {
372 *unicode = *--text;
373 return text;
374 }
375
376 static unsigned int
strlenhb_latin1_t377 strlen (const codepoint_t *text)
378 {
379 unsigned int l = 0;
380 while (*text++) l++;
381 return l;
382 }
383
384 static unsigned int
encode_lenhb_latin1_t385 encode_len (hb_codepoint_t unicode HB_UNUSED)
386 {
387 return 1;
388 }
389
390 static codepoint_t *
encodehb_latin1_t391 encode (codepoint_t *text,
392 const codepoint_t *end HB_UNUSED,
393 hb_codepoint_t unicode)
394 {
395 if (unlikely (unicode >= 0x0100u))
396 unicode = '?';
397 *text++ = unicode;
398 return text;
399 }
400 };
401
402
403 struct hb_ascii_t
404 {
405 typedef uint8_t codepoint_t;
406 static constexpr unsigned max_len = 1;
407
408 static const codepoint_t *
nexthb_ascii_t409 next (const codepoint_t *text,
410 const codepoint_t *end HB_UNUSED,
411 hb_codepoint_t *unicode,
412 hb_codepoint_t replacement)
413 {
414 *unicode = *text++;
415 if (*unicode >= 0x0080u)
416 *unicode = replacement;
417 return text;
418 }
419
420 static const codepoint_t *
prevhb_ascii_t421 prev (const codepoint_t *text,
422 const codepoint_t *start HB_UNUSED,
423 hb_codepoint_t *unicode,
424 hb_codepoint_t replacement)
425 {
426 *unicode = *--text;
427 if (*unicode >= 0x0080u)
428 *unicode = replacement;
429 return text;
430 }
431
432 static unsigned int
strlenhb_ascii_t433 strlen (const codepoint_t *text)
434 {
435 unsigned int l = 0;
436 while (*text++) l++;
437 return l;
438 }
439
440 static unsigned int
encode_lenhb_ascii_t441 encode_len (hb_codepoint_t unicode HB_UNUSED)
442 {
443 return 1;
444 }
445
446 static codepoint_t *
encodehb_ascii_t447 encode (codepoint_t *text,
448 const codepoint_t *end HB_UNUSED,
449 hb_codepoint_t unicode)
450 {
451 if (unlikely (unicode >= 0x0080u))
452 unicode = '?';
453 *text++ = unicode;
454 return text;
455 }
456 };
457
458 template <typename utf_t>
459 static inline const typename utf_t::codepoint_t *
hb_utf_offset_to_pointer(const typename utf_t::codepoint_t * start,signed offset)460 hb_utf_offset_to_pointer (const typename utf_t::codepoint_t *start,
461 signed offset)
462 {
463 hb_codepoint_t unicode;
464
465 while (offset-- > 0)
466 start = utf_t::next (start,
467 start + utf_t::max_len,
468 &unicode,
469 HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT);
470
471 while (offset++ < 0)
472 start = utf_t::prev (start,
473 start - utf_t::max_len,
474 &unicode,
475 HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT);
476
477 return start;
478 }
479
480
481 #endif /* HB_UTF_HH */
482