rune.c (3963B)
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 11 * ANY 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 "plan9.h" 17 #include "utf.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, /* 0011 1111 1111 1111 1111 1111 */ 39 40 Maskx = (1<<Bitx)-1, /* 0011 1111 */ 41 Testx = Maskx ^ 0xFF, /* 1100 0000 */ 42 43 Bad = Runeerror 44 }; 45 46 int 47 chartorune(Rune *rune, char *str) 48 { 49 int c, c1, c2, c3; 50 long l; 51 52 /* 53 * one character sequence 54 * 00000-0007F => T1 55 */ 56 c = *(uchar*)str; 57 if(c < Tx) { 58 *rune = c; 59 return 1; 60 } 61 62 /* 63 * two character sequence 64 * 0080-07FF => T2 Tx 65 */ 66 c1 = *(uchar*)(str+1) ^ Tx; 67 if(c1 & Testx) 68 goto bad; 69 if(c < T3) { 70 if(c < T2) 71 goto bad; 72 l = ((c << Bitx) | c1) & Rune2; 73 if(l <= Rune1) 74 goto bad; 75 *rune = l; 76 return 2; 77 } 78 79 /* 80 * three character sequence 81 * 0800-FFFF => T3 Tx Tx 82 */ 83 c2 = *(uchar*)(str+2) ^ Tx; 84 if(c2 & Testx) 85 goto bad; 86 if(c < T4) { 87 l = ((((c << Bitx) | c1) << Bitx) | c2) & Rune3; 88 if(l <= Rune2) 89 goto bad; 90 *rune = l; 91 return 3; 92 } 93 94 /* 95 * four character sequence 96 * 10000-10FFFF => T4 Tx Tx Tx 97 */ 98 if(UTFmax >= 4) { 99 c3 = *(uchar*)(str+3) ^ Tx; 100 if(c3 & Testx) 101 goto bad; 102 if(c < T5) { 103 l = ((((((c << Bitx) | c1) << Bitx) | c2) << Bitx) | c3) & Rune4; 104 if(l <= Rune3) 105 goto bad; 106 if(l > Runemax) 107 goto bad; 108 *rune = l; 109 return 4; 110 } 111 } 112 113 /* 114 * bad decoding 115 */ 116 bad: 117 *rune = Bad; 118 return 1; 119 } 120 121 int 122 runetochar(char *str, Rune *rune) 123 { 124 long c; 125 126 /* 127 * one character sequence 128 * 00000-0007F => 00-7F 129 */ 130 c = *rune; 131 if(c <= Rune1) { 132 str[0] = c; 133 return 1; 134 } 135 136 /* 137 * two character sequence 138 * 00080-007FF => T2 Tx 139 */ 140 if(c <= Rune2) { 141 str[0] = T2 | (c >> 1*Bitx); 142 str[1] = Tx | (c & Maskx); 143 return 2; 144 } 145 146 /* 147 * three character sequence 148 * 00800-0FFFF => T3 Tx Tx 149 */ 150 if(c > Runemax) 151 c = Runeerror; 152 if(c <= Rune3) { 153 str[0] = T3 | (c >> 2*Bitx); 154 str[1] = Tx | ((c >> 1*Bitx) & Maskx); 155 str[2] = Tx | (c & Maskx); 156 return 3; 157 } 158 159 /* 160 * four character sequence 161 * 010000-1FFFFF => T4 Tx Tx Tx 162 */ 163 str[0] = T4 | (c >> 3*Bitx); 164 str[1] = Tx | ((c >> 2*Bitx) & Maskx); 165 str[2] = Tx | ((c >> 1*Bitx) & Maskx); 166 str[3] = Tx | (c & Maskx); 167 return 4; 168 } 169 170 int 171 runelen(long c) 172 { 173 Rune rune; 174 char str[10]; 175 176 rune = c; 177 return runetochar(str, &rune); 178 } 179 180 int 181 runenlen(Rune *r, int nrune) 182 { 183 int nb, c; 184 185 nb = 0; 186 while(nrune--) { 187 c = *r++; 188 if(c <= Rune1) 189 nb++; 190 else 191 if(c <= Rune2) 192 nb += 2; 193 else 194 if(c <= Rune3 || c > Runemax) 195 nb += 3; 196 else 197 nb += 4; 198 } 199 return nb; 200 } 201 202 int 203 fullrune(char *str, int n) 204 { 205 int c; 206 207 if(n <= 0) 208 return 0; 209 c = *(uchar*)str; 210 if(c < Tx) 211 return 1; 212 if(c < T3) 213 return n >= 2; 214 if(UTFmax == 3 || c < T4) 215 return n >= 3; 216 return n >= 4; 217 }