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_PRIVATE_HH
28 #define HB_UTF_PRIVATE_HH
29
30 #include "hb-private.hh"
31
32
33 struct hb_utf8_t
34 {
35 typedef uint8_t codepoint_t;
36
37 static inline const uint8_t *
38 next (const uint8_t *text,
39 const uint8_t *end,
40 hb_codepoint_t *unicode,
41 hb_codepoint_t replacement)
42 {
43 /* Written to only accept well-formed sequences.
44 * Based on ideas from ICU's U8_NEXT.
45 * Generates one "replacement" for each ill-formed byte. */
46
47 hb_codepoint_t c = *text++;
48
49 if (c > 0x7Fu)
50 {
51 if (hb_in_range<hb_codepoint_t> (c, 0xC2u, 0xDFu)) /* Two-byte */
52 {
53 unsigned int t1;
54 if (likely (text < end &&
55 (t1 = text[0] - 0x80u) <= 0x3Fu))
56 {
57 c = ((c&0x1Fu)<<6) | t1;
58 text++;
59 }
60 else
61 goto error;
62 }
63 else if (hb_in_range<hb_codepoint_t> (c, 0xE0u, 0xEFu)) /* Three-byte */
64 {
65 unsigned int t1, t2;
66 if (likely (1 < end - text &&
67 (t1 = text[0] - 0x80u) <= 0x3Fu &&
68 (t2 = text[1] - 0x80u) <= 0x3Fu))
69 {
70 c = ((c&0xFu)<<12) | (t1<<6) | t2;
71 if (unlikely (c < 0x0800u || hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
72 goto error;
73 text += 2;
74 }
75 else
76 goto error;
77 }
78 else if (hb_in_range<hb_codepoint_t> (c, 0xF0u, 0xF4u)) /* Four-byte */
79 {
80 unsigned int t1, t2, t3;
81 if (likely (2 < end - text &&
82 (t1 = text[0] - 0x80u) <= 0x3Fu &&
83 (t2 = text[1] - 0x80u) <= 0x3Fu &&
84 (t3 = text[2] - 0x80u) <= 0x3Fu))
85 {
86 c = ((c&0x7u)<<18) | (t1<<12) | (t2<<6) | t3;
87 if (unlikely (!hb_in_range<hb_codepoint_t> (c, 0x10000u, 0x10FFFFu)))
88 goto error;
89 text += 3;
90 }
91 else
92 goto error;
93 }
94 else
95 goto error;
96 }
97
98 *unicode = c;
99 return text;
100
101 error:
102 *unicode = replacement;
103 return text;
104 }
105
106 static inline const uint8_t *
107 prev (const uint8_t *text,
108 const uint8_t *start,
109 hb_codepoint_t *unicode,
110 hb_codepoint_t replacement)
111 {
112 const uint8_t *end = text--;
113 while (start < text && (*text & 0xc0) == 0x80 && end - text < 4)
114 text--;
115
116 if (likely (next (text, end, unicode, replacement) == end))
117 return text;
118
119 *unicode = replacement;
120 return end - 1;
121 }
122
123 static inline unsigned int
124 strlen (const uint8_t *text)
125 {
126 return ::strlen ((const char *) text);
127 }
128 };
129
130
131 struct hb_utf16_t
132 {
133 typedef uint16_t codepoint_t;
134
135 static inline const uint16_t *
136 next (const uint16_t *text,
137 const uint16_t *end,
138 hb_codepoint_t *unicode,
139 hb_codepoint_t replacement)
140 {
141 hb_codepoint_t c = *text++;
142
143 if (likely (!hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
144 {
145 *unicode = c;
146 return text;
147 }
148
149 if (likely (c <= 0xDBFFu && text < end))
150 {
151 /* High-surrogate in c */
152 hb_codepoint_t l = *text;
153 if (likely (hb_in_range<hb_codepoint_t> (l, 0xDC00u, 0xDFFFu)))
154 {
155 /* Low-surrogate in l */
156 *unicode = (c << 10) + l - ((0xD800u << 10) - 0x10000u + 0xDC00u);
157 text++;
158 return text;
159 }
160 }
161
162 /* Lonely / out-of-order surrogate. */
163 *unicode = replacement;
164 return text;
165 }
166
167 static inline const uint16_t *
168 prev (const uint16_t *text,
169 const uint16_t *start,
170 hb_codepoint_t *unicode,
171 hb_codepoint_t replacement)
172 {
173 hb_codepoint_t c = *--text;
174
175 if (likely (!hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
176 {
177 *unicode = c;
178 return text;
179 }
180
181 if (likely (c >= 0xDC00u && start < text))
182 {
183 /* Low-surrogate in c */
184 hb_codepoint_t h = text[-1];
185 if (likely (hb_in_range<hb_codepoint_t> (h, 0xD800u, 0xDBFFu)))
186 {
187 /* High-surrogate in h */
188 *unicode = (h << 10) + c - ((0xD800u << 10) - 0x10000u + 0xDC00u);
189 text--;
190 return text;
191 }
192 }
193
194 /* Lonely / out-of-order surrogate. */
195 *unicode = replacement;
196 return text;
197 }
198
199
200 static inline unsigned int
201 strlen (const uint16_t *text)
202 {
203 unsigned int l = 0;
204 while (*text++) l++;
205 return l;
206 }
207 };
208
209
210 template <bool validate=true>
211 struct hb_utf32_t
212 {
213 typedef uint32_t codepoint_t;
214
215 static inline const uint32_t *
216 next (const uint32_t *text,
217 const uint32_t *end HB_UNUSED,
218 hb_codepoint_t *unicode,
219 hb_codepoint_t replacement)
220 {
221 hb_codepoint_t c = *unicode = *text++;
222 if (validate && unlikely (c >= 0xD800u && (c <= 0xDFFFu || c > 0x10FFFFu)))
223 *unicode = replacement;
224 return text;
225 }
226
227 static inline const uint32_t *
228 prev (const uint32_t *text,
229 const uint32_t *start HB_UNUSED,
230 hb_codepoint_t *unicode,
231 hb_codepoint_t replacement)
232 {
233 hb_codepoint_t c = *unicode = *--text;
234 if (validate && unlikely (c >= 0xD800u && (c <= 0xDFFFu || c > 0x10FFFFu)))
235 *unicode = replacement;
236 return text;
237 }
238
239 static inline unsigned int
240 strlen (const uint32_t *text)
241 {
242 unsigned int l = 0;
243 while (*text++) l++;
244 return l;
245 }
246 };
247
248
249 struct hb_latin1_t
250 {
251 typedef uint8_t codepoint_t;
252
253 static inline const uint8_t *
254 next (const uint8_t *text,
255 const uint8_t *end HB_UNUSED,
256 hb_codepoint_t *unicode,
257 hb_codepoint_t replacement HB_UNUSED)
258 {
259 *unicode = *text++;
260 return text;
261 }
262
263 static inline const uint8_t *
264 prev (const uint8_t *text,
265 const uint8_t *start HB_UNUSED,
266 hb_codepoint_t *unicode,
267 hb_codepoint_t replacement)
268 {
269 *unicode = *--text;
270 return text;
271 }
272
273 static inline unsigned int
274 strlen (const uint8_t *text)
275 {
276 unsigned int l = 0;
277 while (*text++) l++;
278 return l;
279 }
280 };
281
282 #endif /* HB_UTF_PRIVATE_HH */