1 /* Grapheme cluster breaks in Unicode strings. 2 Copyright (C) 2010-2021 Free Software Foundation, Inc. 3 Written by Ben Pfaff <blp@cs.stanford.edu>, 2010. 4 5 This file is free software. 6 It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+". 7 You can redistribute it and/or modify it under either 8 - the terms of the GNU Lesser General Public License as published 9 by the Free Software Foundation; either version 3, or (at your 10 option) any later version, or 11 - the terms of the GNU General Public License as published by the 12 Free Software Foundation; either version 2, or (at your option) 13 any later version, or 14 - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+". 15 16 This file is distributed in the hope that it will be useful, 17 but WITHOUT ANY WARRANTY; without even the implied warranty of 18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 19 Lesser General Public License and the GNU General Public License 20 for more details. 21 22 You should have received a copy of the GNU Lesser General Public 23 License and of the GNU General Public License along with this 24 program. If not, see <https://www.gnu.org/licenses/>. */ 25 26 #ifndef _UNIGBRK_H 27 #define _UNIGBRK_H 28 29 /* Get bool. */ 30 #include <stdbool.h> 31 32 /* Get size_t. */ 33 #include <stddef.h> 34 35 #include "unitypes.h" 36 37 #ifdef __cplusplus 38 extern "C" { 39 #endif 40 41 /* ========================================================================= */ 42 43 /* Property defined in Unicode Standard Annex #29, section "Grapheme Cluster 44 Boundaries" 45 <https://unicode.org/reports/tr29/#Grapheme_Cluster_Boundaries> */ 46 47 /* Possible values of the Grapheme_Cluster_Break property. 48 This enumeration may be extended in the future. */ 49 enum 50 { 51 GBP_OTHER = 0, 52 GBP_CR = 1, 53 GBP_LF = 2, 54 GBP_CONTROL = 3, 55 GBP_EXTEND = 4, 56 GBP_PREPEND = 5, 57 GBP_SPACINGMARK = 6, 58 GBP_L = 7, 59 GBP_V = 8, 60 GBP_T = 9, 61 GBP_LV = 10, 62 GBP_LVT = 11, 63 GBP_RI = 12, 64 GBP_ZWJ = 13, 65 GBP_EB = 14, 66 GBP_EM = 15, 67 GBP_GAZ = 16, 68 GBP_EBG = 17 69 }; 70 71 /* Return the Grapheme_Cluster_Break property of a Unicode character. */ 72 extern int 73 uc_graphemeclusterbreak_property (ucs4_t uc) 74 _UC_ATTRIBUTE_CONST; 75 76 /* ========================================================================= */ 77 78 /* Grapheme cluster breaks. */ 79 80 /* Returns true if there is a grapheme cluster boundary between Unicode code 81 points A and B. A "grapheme cluster" is an approximation to a 82 user-perceived character, which sometimes corresponds to multiple code 83 points. For example, an English letter followed by an acute accent can be 84 expressed as two consecutive Unicode code points, but it is perceived by the 85 user as only a single character and therefore constitutes a single grapheme 86 cluster. 87 88 Implements extended (not legacy) grapheme cluster rules, because UAX #29 89 indicates that they are preferred. 90 91 Use A == 0 or B == 0 to indicate start of text or end of text, 92 respectively. */ 93 extern bool 94 uc_is_grapheme_break (ucs4_t a, ucs4_t b) 95 _UC_ATTRIBUTE_CONST; 96 97 /* Returns the start of the next grapheme cluster following S, or NULL if the 98 end of the string has been reached. */ 99 extern const uint8_t * 100 u8_grapheme_next (const uint8_t *s, const uint8_t *end) 101 _UC_ATTRIBUTE_PURE; 102 extern const uint16_t * 103 u16_grapheme_next (const uint16_t *s, const uint16_t *end) 104 _UC_ATTRIBUTE_PURE; 105 extern const uint32_t * 106 u32_grapheme_next (const uint32_t *s, const uint32_t *end) 107 _UC_ATTRIBUTE_PURE; 108 109 /* Returns the start of the previous grapheme cluster before S, or NULL if the 110 start of the string has been reached. */ 111 extern const uint8_t * 112 u8_grapheme_prev (const uint8_t *s, const uint8_t *start) 113 _UC_ATTRIBUTE_PURE; 114 extern const uint16_t * 115 u16_grapheme_prev (const uint16_t *s, const uint16_t *start) 116 _UC_ATTRIBUTE_PURE; 117 extern const uint32_t * 118 u32_grapheme_prev (const uint32_t *s, const uint32_t *start) 119 _UC_ATTRIBUTE_PURE; 120 121 /* Determine the grapheme cluster boundaries in S, and store the result at 122 p[0..n-1]. p[i] = 1 means that a new grapheme cluster begins at s[i]. p[i] 123 = 0 means that s[i-1] and s[i] are part of the same grapheme cluster. p[0] 124 will always be 1. 125 */ 126 extern void 127 u8_grapheme_breaks (const uint8_t *s, size_t n, char *p); 128 extern void 129 u16_grapheme_breaks (const uint16_t *s, size_t n, char *p); 130 extern void 131 u32_grapheme_breaks (const uint32_t *s, size_t n, char *p); 132 extern void 133 ulc_grapheme_breaks (const char *s, size_t n, char *p); 134 extern void 135 uc_grapheme_breaks (const ucs4_t *s, size_t n, char *p); 136 137 /* ========================================================================= */ 138 139 #ifdef __cplusplus 140 } 141 #endif 142 143 144 #endif /* _UNIGBRK_H */