1 /* 2 * The authors of this software are Rob Pike and Ken Thompson. 3 * Copyright (c) 2002 by Lucent Technologies. 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose without fee is hereby granted, provided that this entire notice 6 * is included in all copies of any software which is or includes a copy 7 * or modification of this software and in all copies of the supporting 8 * documentation for such software. 9 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED 10 * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY 11 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY 12 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. 13 */ 14 #include <stdarg.h> 15 #include <string.h> 16 #include "utf.h" 17 #include "utfdef.h" 18 19 enum 20 { 21 Bit1 = 7, 22 Bitx = 6, 23 Bit2 = 5, 24 Bit3 = 4, 25 Bit4 = 3, 26 Bit5 = 2, 27 28 T1 = ((1<<(Bit1+1))-1) ^ 0xFF, /* 0000 0000 */ 29 Tx = ((1<<(Bitx+1))-1) ^ 0xFF, /* 1000 0000 */ 30 T2 = ((1<<(Bit2+1))-1) ^ 0xFF, /* 1100 0000 */ 31 T3 = ((1<<(Bit3+1))-1) ^ 0xFF, /* 1110 0000 */ 32 T4 = ((1<<(Bit4+1))-1) ^ 0xFF, /* 1111 0000 */ 33 T5 = ((1<<(Bit5+1))-1) ^ 0xFF, /* 1111 1000 */ 34 35 Rune1 = (1<<(Bit1+0*Bitx))-1, /* 0000 0000 0000 0000 0111 1111 */ 36 Rune2 = (1<<(Bit2+1*Bitx))-1, /* 0000 0000 0000 0111 1111 1111 */ 37 Rune3 = (1<<(Bit3+2*Bitx))-1, /* 0000 0000 1111 1111 1111 1111 */ 38 Rune4 = (1<<(Bit4+3*Bitx))-1, /* 0001 1111 1111 1111 1111 1111 */ 39 40 Maskx = (1<<Bitx)-1, /* 0011 1111 */ 41 Testx = Maskx ^ 0xFF, /* 1100 0000 */ 42 43 SurrogateMin = 0xD800, 44 SurrogateMax = 0xDFFF, 45 46 Bad = Runeerror, 47 }; 48 49 int 50 chartorune(Rune *rune, char *str) 51 { 52 int c, c1, c2, c3; 53 long l; 54 55 /* 56 * one character sequence 57 * 00000-0007F => T1 58 */ 59 c = *(uchar*)str; 60 if(c < Tx) { 61 *rune = c; 62 return 1; 63 } 64 65 /* 66 * two character sequence 67 * 00080-007FF => T2 Tx 68 */ 69 c1 = *(uchar*)(str+1) ^ Tx; 70 if(c1 & Testx) 71 goto bad; 72 if(c < T3) { 73 if(c < T2) 74 goto bad; 75 l = ((c << Bitx) | c1) & Rune2; 76 if(l <= Rune1) 77 goto bad; 78 *rune = l; 79 return 2; 80 } 81 82 /* 83 * three character sequence 84 * 00800-0FFFF => T3 Tx Tx 85 */ 86 c2 = *(uchar*)(str+2) ^ Tx; 87 88 if(c2 & Testx) 89 goto bad; 90 if(c < T4) { 91 l = ((((c << Bitx) | c1) << Bitx) | c2) & Rune3; 92 if(l <= Rune2) 93 goto bad; 94 if (SurrogateMin <= l && l <= SurrogateMax) 95 goto bad; 96 *rune = l; 97 return 3; 98 } 99 100 /* 101 * four character sequence 102 * 10000-10FFFF => T4 Tx Tx Tx 103 */ 104 if(UTFmax >= 4) { 105 c3 = *(uchar*)(str+3) ^ Tx; 106 if(c3 & Testx) 107 goto bad; 108 if(c < T5) { 109 l = ((((((c << Bitx) | c1) << Bitx) | c2) << Bitx) | c3) & Rune4; 110 if(l <= Rune3) 111 goto bad; 112 if(l > Runemax) 113 goto bad; 114 *rune = l; 115 return 4; 116 } 117 } 118 119 /* 120 * bad decoding 121 */ 122 bad: 123 *rune = Bad; 124 return 1; 125 } 126 127 int 128 runetochar(char *str, Rune *rune) 129 { 130 long c; 131 132 /* 133 * one character sequence 134 * 00000-0007F => 00-7F 135 */ 136 c = *rune; 137 if(c <= Rune1) { 138 str[0] = c; 139 return 1; 140 } 141 142 /* 143 * two character sequence 144 * 0080-07FF => T2 Tx 145 */ 146 if(c <= Rune2) { 147 str[0] = T2 | (c >> 1*Bitx); 148 str[1] = Tx | (c & Maskx); 149 return 2; 150 } 151 /* 152 * If the Rune is out of range or a surrogate half, convert it to the error rune. 153 * Do this test here because the error rune encodes to three bytes. 154 * Doing it earlier would duplicate work, since an out of range 155 * Rune wouldn't have fit in one or two bytes. 156 */ 157 if (c > Runemax) 158 c = Runeerror; 159 if (SurrogateMin <= c && c <= SurrogateMax) 160 c = Runeerror; 161 162 /* 163 * three character sequence 164 * 0800-FFFF => T3 Tx Tx 165 */ 166 if (c <= Rune3) { 167 str[0] = T3 | (c >> 2*Bitx); 168 str[1] = Tx | ((c >> 1*Bitx) & Maskx); 169 str[2] = Tx | (c & Maskx); 170 return 3; 171 } 172 173 /* 174 * four character sequence (21-bit value) 175 * 10000-1FFFFF => T4 Tx Tx Tx 176 */ 177 str[0] = T4 | (c >> 3*Bitx); 178 str[1] = Tx | ((c >> 2*Bitx) & Maskx); 179 str[2] = Tx | ((c >> 1*Bitx) & Maskx); 180 str[3] = Tx | (c & Maskx); 181 return 4; 182 } 183 184 int 185 runelen(long c) 186 { 187 Rune rune; 188 char str[10]; 189 190 rune = c; 191 return runetochar(str, &rune); 192 } 193 194 int 195 runenlen(Rune *r, int nrune) 196 { 197 int nb, c; 198 199 nb = 0; 200 while(nrune--) { 201 c = *r++; 202 if(c <= Rune1) 203 nb++; 204 else if(c <= Rune2) 205 nb += 2; 206 else if(c <= Rune3) 207 nb += 3; 208 else 209 nb += 4; 210 } 211 return nb; 212 } 213 214 int 215 fullrune(char *str, int n) 216 { 217 int c; 218 if(n <= 0) 219 return 0; 220 c = *(uchar*)str; 221 if(c < Tx) 222 return 1; 223 if(c < T3) 224 return n >= 2; 225 if(c < T4) 226 return n >= 3; 227 return n >= 4; 228 } 229