1/* 2 * Copyright (c) 2009-2014 Petri Lehtinen <petri@digip.org> 3 * 4 * Jansson is free software; you can redistribute it and/or modify 5 * it under the terms of the MIT license. See LICENSE for details. 6 */ 7 8#include <string.h> 9#include "utf.h" 10 11int utf8_encode(int32_t codepoint, char *buffer, size_t *size) 12{ 13 if(codepoint < 0) 14 return -1; 15 else if(codepoint < 0x80) 16 { 17 buffer[0] = (char)codepoint; 18 *size = 1; 19 } 20 else if(codepoint < 0x800) 21 { 22 buffer[0] = 0xC0 + ((codepoint & 0x7C0) >> 6); 23 buffer[1] = 0x80 + ((codepoint & 0x03F)); 24 *size = 2; 25 } 26 else if(codepoint < 0x10000) 27 { 28 buffer[0] = 0xE0 + ((codepoint & 0xF000) >> 12); 29 buffer[1] = 0x80 + ((codepoint & 0x0FC0) >> 6); 30 buffer[2] = 0x80 + ((codepoint & 0x003F)); 31 *size = 3; 32 } 33 else if(codepoint <= 0x10FFFF) 34 { 35 buffer[0] = 0xF0 + ((codepoint & 0x1C0000) >> 18); 36 buffer[1] = 0x80 + ((codepoint & 0x03F000) >> 12); 37 buffer[2] = 0x80 + ((codepoint & 0x000FC0) >> 6); 38 buffer[3] = 0x80 + ((codepoint & 0x00003F)); 39 *size = 4; 40 } 41 else 42 return -1; 43 44 return 0; 45} 46 47size_t utf8_check_first(char byte) 48{ 49 unsigned char u = (unsigned char)byte; 50 51 if(u < 0x80) 52 return 1; 53 54 if(0x80 <= u && u <= 0xBF) { 55 /* second, third or fourth byte of a multi-byte 56 sequence, i.e. a "continuation byte" */ 57 return 0; 58 } 59 else if(u == 0xC0 || u == 0xC1) { 60 /* overlong encoding of an ASCII byte */ 61 return 0; 62 } 63 else if(0xC2 <= u && u <= 0xDF) { 64 /* 2-byte sequence */ 65 return 2; 66 } 67 68 else if(0xE0 <= u && u <= 0xEF) { 69 /* 3-byte sequence */ 70 return 3; 71 } 72 else if(0xF0 <= u && u <= 0xF4) { 73 /* 4-byte sequence */ 74 return 4; 75 } 76 else { /* u >= 0xF5 */ 77 /* Restricted (start of 4-, 5- or 6-byte sequence) or invalid 78 UTF-8 */ 79 return 0; 80 } 81} 82 83size_t utf8_check_full(const char *buffer, size_t size, int32_t *codepoint) 84{ 85 size_t i; 86 int32_t value = 0; 87 unsigned char u = (unsigned char)buffer[0]; 88 89 if(size == 2) 90 { 91 value = u & 0x1F; 92 } 93 else if(size == 3) 94 { 95 value = u & 0xF; 96 } 97 else if(size == 4) 98 { 99 value = u & 0x7; 100 } 101 else 102 return 0; 103 104 for(i = 1; i < size; i++) 105 { 106 u = (unsigned char)buffer[i]; 107 108 if(u < 0x80 || u > 0xBF) { 109 /* not a continuation byte */ 110 return 0; 111 } 112 113 value = (value << 6) + (u & 0x3F); 114 } 115 116 if(value > 0x10FFFF) { 117 /* not in Unicode range */ 118 return 0; 119 } 120 121 else if(0xD800 <= value && value <= 0xDFFF) { 122 /* invalid code point (UTF-16 surrogate halves) */ 123 return 0; 124 } 125 126 else if((size == 2 && value < 0x80) || 127 (size == 3 && value < 0x800) || 128 (size == 4 && value < 0x10000)) { 129 /* overlong encoding */ 130 return 0; 131 } 132 133 if(codepoint) 134 *codepoint = value; 135 136 return 1; 137} 138 139const char *utf8_iterate(const char *buffer, size_t bufsize, int32_t *codepoint) 140{ 141 size_t count; 142 int32_t value; 143 144 if(!bufsize) 145 return buffer; 146 147 count = utf8_check_first(buffer[0]); 148 if(count <= 0) 149 return NULL; 150 151 if(count == 1) 152 value = (unsigned char)buffer[0]; 153 else 154 { 155 if(count > bufsize || !utf8_check_full(buffer, count, &value)) 156 return NULL; 157 } 158 159 if(codepoint) 160 *codepoint = value; 161 162 return buffer + count; 163} 164 165int utf8_check_string(const char *string, size_t length) 166{ 167 size_t i; 168 169 for(i = 0; i < length; i++) 170 { 171 size_t count = utf8_check_first(string[i]); 172 if(count == 0) 173 return 0; 174 else if(count > 1) 175 { 176 if(count > length - i) 177 return 0; 178 179 if(!utf8_check_full(&string[i], count, NULL)) 180 return 0; 181 182 i += count - 1; 183 } 184 } 185 186 return 1; 187} 188