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1 /* | |
2 ******************************************************************************* | |
3 * | |
4 * Copyright (C) 1999-2010, International Business Machines | |
5 * Corporation and others. All Rights Reserved. | |
6 * | |
7 ******************************************************************************* | |
8 * file name: utf.h | |
9 * encoding: US-ASCII | |
10 * tab size: 8 (not used) | |
11 * indentation:4 | |
12 * | |
13 * created on: 1999sep09 | |
14 * created by: Markus W. Scherer | |
15 */ | |
16 | |
17 /** | |
18 * \file | |
19 * \brief C API: Code point macros | |
20 * | |
21 * This file defines macros for checking whether a code point is | |
22 * a surrogate or a non-character etc. | |
23 * | |
24 * The UChar and UChar32 data types for Unicode code units and code points | |
25 * are defined in umachines.h because they can be machine-dependent. | |
26 * | |
27 * utf.h is included by utypes.h and itself includes utf8.h and utf16.h after so
me | |
28 * common definitions. Those files define macros for efficiently getting code po
ints | |
29 * in and out of UTF-8/16 strings. | |
30 * utf16.h macros have "U16_" prefixes. | |
31 * utf8.h defines similar macros with "U8_" prefixes for UTF-8 string handling. | |
32 * | |
33 * ICU processes 16-bit Unicode strings. | |
34 * Most of the time, such strings are well-formed UTF-16. | |
35 * Single, unpaired surrogates must be handled as well, and are treated in ICU | |
36 * like regular code points where possible. | |
37 * (Pairs of surrogate code points are indistinguishable from supplementary | |
38 * code points encoded as pairs of supplementary code units.) | |
39 * | |
40 * In fact, almost all Unicode code points in normal text (>99%) | |
41 * are on the BMP (<=U+ffff) and even <=U+d7ff. | |
42 * ICU functions handle supplementary code points (U+10000..U+10ffff) | |
43 * but are optimized for the much more frequently occurring BMP code points. | |
44 * | |
45 * utf.h defines UChar to be an unsigned 16-bit integer. If this matches wchar_t
, then | |
46 * UChar is defined to be exactly wchar_t, otherwise uint16_t. | |
47 * | |
48 * UChar32 is defined to be a signed 32-bit integer (int32_t), large enough for
a 21-bit | |
49 * Unicode code point (Unicode scalar value, 0..0x10ffff). | |
50 * Before ICU 2.4, the definition of UChar32 was similarly platform-dependent as | |
51 * the definition of UChar. For details see the documentation for UChar32 itself
. | |
52 * | |
53 * utf.h also defines a small number of C macros for single Unicode code points. | |
54 * These are simple checks for surrogates and non-characters. | |
55 * For actual Unicode character properties see uchar.h. | |
56 * | |
57 * By default, string operations must be done with error checking in case | |
58 * a string is not well-formed UTF-16. | |
59 * The macros will detect if a surrogate code unit is unpaired | |
60 * (lead unit without trail unit or vice versa) and just return the unit itself | |
61 * as the code point. | |
62 * (It is an accidental property of Unicode and UTF-16 that all | |
63 * malformed sequences can be expressed unambiguously with a distinct subrange | |
64 * of Unicode code points.) | |
65 * | |
66 * The regular "safe" macros require that the initial, passed-in string index | |
67 * is within bounds. They only check the index when they read more than one | |
68 * code unit. This is usually done with code similar to the following loop: | |
69 * <pre>while(i<length) { | |
70 * U16_NEXT(s, i, length, c); | |
71 * // use c | |
72 * }</pre> | |
73 * | |
74 * When it is safe to assume that text is well-formed UTF-16 | |
75 * (does not contain single, unpaired surrogates), then one can use | |
76 * U16_..._UNSAFE macros. | |
77 * These do not check for proper code unit sequences or truncated text and may | |
78 * yield wrong results or even cause a crash if they are used with "malformed" | |
79 * text. | |
80 * In practice, U16_..._UNSAFE macros will produce slightly less code but | |
81 * should not be faster because the processing is only different when a | |
82 * surrogate code unit is detected, which will be rare. | |
83 * | |
84 * Similarly for UTF-8, there are "safe" macros without a suffix, | |
85 * and U8_..._UNSAFE versions. | |
86 * The performance differences are much larger here because UTF-8 provides so | |
87 * many opportunities for malformed sequences. | |
88 * The unsafe UTF-8 macros are entirely implemented inside the macro definitions | |
89 * and are fast, while the safe UTF-8 macros call functions for all but the | |
90 * trivial (ASCII) cases. | |
91 * (ICU 3.6 optimizes U8_NEXT() and U8_APPEND() to handle most other common | |
92 * characters inline as well.) | |
93 * | |
94 * Unlike with UTF-16, malformed sequences cannot be expressed with distinct | |
95 * code point values (0..U+10ffff). They are indicated with negative values inst
ead. | |
96 * | |
97 * For more information see the ICU User Guide Strings chapter | |
98 * (http://icu-project.org/userguide/strings.html). | |
99 * | |
100 * <em>Usage:</em> | |
101 * ICU coding guidelines for if() statements should be followed when using these
macros. | |
102 * Compound statements (curly braces {}) must be used for if-else-while... | |
103 * bodies and all macro statements should be terminated with semicolon. | |
104 * | |
105 * @stable ICU 2.4 | |
106 */ | |
107 | |
108 #ifndef __UTF_H__ | |
109 #define __UTF_H__ | |
110 | |
111 #include "unicode/utypes.h" | |
112 /* include the utfXX.h after the following definitions */ | |
113 | |
114 /* single-code point definitions -------------------------------------------- */ | |
115 | |
116 /** | |
117 * This value is intended for sentinel values for APIs that | |
118 * (take or) return single code points (UChar32). | |
119 * It is outside of the Unicode code point range 0..0x10ffff. | |
120 * | |
121 * For example, a "done" or "error" value in a new API | |
122 * could be indicated with U_SENTINEL. | |
123 * | |
124 * ICU APIs designed before ICU 2.4 usually define service-specific "done" | |
125 * values, mostly 0xffff. | |
126 * Those may need to be distinguished from | |
127 * actual U+ffff text contents by calling functions like | |
128 * CharacterIterator::hasNext() or UnicodeString::length(). | |
129 * | |
130 * @return -1 | |
131 * @see UChar32 | |
132 * @stable ICU 2.4 | |
133 */ | |
134 #define U_SENTINEL (-1) | |
135 | |
136 /** | |
137 * Is this code point a Unicode noncharacter? | |
138 * @param c 32-bit code point | |
139 * @return TRUE or FALSE | |
140 * @stable ICU 2.4 | |
141 */ | |
142 #define U_IS_UNICODE_NONCHAR(c) \ | |
143 ((c)>=0xfdd0 && \ | |
144 ((uint32_t)(c)<=0xfdef || ((c)&0xfffe)==0xfffe) && \ | |
145 (uint32_t)(c)<=0x10ffff) | |
146 | |
147 /** | |
148 * Is c a Unicode code point value (0..U+10ffff) | |
149 * that can be assigned a character? | |
150 * | |
151 * Code points that are not characters include: | |
152 * - single surrogate code points (U+d800..U+dfff, 2048 code points) | |
153 * - the last two code points on each plane (U+__fffe and U+__ffff, 34 code poin
ts) | |
154 * - U+fdd0..U+fdef (new with Unicode 3.1, 32 code points) | |
155 * - the highest Unicode code point value is U+10ffff | |
156 * | |
157 * This means that all code points below U+d800 are character code points, | |
158 * and that boundary is tested first for performance. | |
159 * | |
160 * @param c 32-bit code point | |
161 * @return TRUE or FALSE | |
162 * @stable ICU 2.4 | |
163 */ | |
164 #define U_IS_UNICODE_CHAR(c) \ | |
165 ((uint32_t)(c)<0xd800 || \ | |
166 ((uint32_t)(c)>0xdfff && \ | |
167 (uint32_t)(c)<=0x10ffff && \ | |
168 !U_IS_UNICODE_NONCHAR(c))) | |
169 | |
170 /** | |
171 * Is this code point a BMP code point (U+0000..U+ffff)? | |
172 * @param c 32-bit code point | |
173 * @return TRUE or FALSE | |
174 * @stable ICU 2.8 | |
175 */ | |
176 #define U_IS_BMP(c) ((uint32_t)(c)<=0xffff) | |
177 | |
178 /** | |
179 * Is this code point a supplementary code point (U+10000..U+10ffff)? | |
180 * @param c 32-bit code point | |
181 * @return TRUE or FALSE | |
182 * @stable ICU 2.8 | |
183 */ | |
184 #define U_IS_SUPPLEMENTARY(c) ((uint32_t)((c)-0x10000)<=0xfffff) | |
185 | |
186 /** | |
187 * Is this code point a lead surrogate (U+d800..U+dbff)? | |
188 * @param c 32-bit code point | |
189 * @return TRUE or FALSE | |
190 * @stable ICU 2.4 | |
191 */ | |
192 #define U_IS_LEAD(c) (((c)&0xfffffc00)==0xd800) | |
193 | |
194 /** | |
195 * Is this code point a trail surrogate (U+dc00..U+dfff)? | |
196 * @param c 32-bit code point | |
197 * @return TRUE or FALSE | |
198 * @stable ICU 2.4 | |
199 */ | |
200 #define U_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00) | |
201 | |
202 /** | |
203 * Is this code point a surrogate (U+d800..U+dfff)? | |
204 * @param c 32-bit code point | |
205 * @return TRUE or FALSE | |
206 * @stable ICU 2.4 | |
207 */ | |
208 #define U_IS_SURROGATE(c) (((c)&0xfffff800)==0xd800) | |
209 | |
210 /** | |
211 * Assuming c is a surrogate code point (U_IS_SURROGATE(c)), | |
212 * is it a lead surrogate? | |
213 * @param c 32-bit code point | |
214 * @return TRUE or FALSE | |
215 * @stable ICU 2.4 | |
216 */ | |
217 #define U_IS_SURROGATE_LEAD(c) (((c)&0x400)==0) | |
218 | |
219 /** | |
220 * Assuming c is a surrogate code point (U_IS_SURROGATE(c)), | |
221 * is it a trail surrogate? | |
222 * @param c 32-bit code point | |
223 * @return TRUE or FALSE | |
224 * @stable ICU 4.2 | |
225 */ | |
226 #define U_IS_SURROGATE_TRAIL(c) (((c)&0x400)!=0) | |
227 | |
228 /* include the utfXX.h ------------------------------------------------------ */ | |
229 | |
230 #include "unicode/utf8.h" | |
231 #include "unicode/utf16.h" | |
232 | |
233 /* utf_old.h contains deprecated, pre-ICU 2.4 definitions */ | |
234 #include "unicode/utf_old.h" | |
235 | |
236 #endif | |
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