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Issue 18836004: Move ICU headers from public/{common,i18n} to source/{common,i18n} (Closed) Base URL: https://chromium.googlesource.com/chromium/deps/icu46.git@master
Patch Set: same as ps #3. retry uploading Created 7 years, 5 months ago
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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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