1 /* ecs - equivalence class routines */ 2 3 /* Copyright (c) 1990 The Regents of the University of California. */ 4 /* All rights reserved. */ 5 6 /* This code is derived from software contributed to Berkeley by */ 7 /* Vern Paxson. */ 8 9 /* The United States Government has rights in this work pursuant */ 10 /* to contract no. DE-AC03-76SF00098 between the United States */ 11 /* Department of Energy and the University of California. */ 12 13 /* This file is part of flex */ 14 15 /* Redistribution and use in source and binary forms, with or without */ 16 /* modification, are permitted provided that the following conditions */ 17 /* are met: */ 18 19 /* 1. Redistributions of source code must retain the above copyright */ 20 /* notice, this list of conditions and the following disclaimer. */ 21 /* 2. Redistributions in binary form must reproduce the above copyright */ 22 /* notice, this list of conditions and the following disclaimer in the */ 23 /* documentation and/or other materials provided with the distribution. */ 24 25 /* Neither the name of the University nor the names of its contributors */ 26 /* may be used to endorse or promote products derived from this software */ 27 /* without specific prior written permission. */ 28 29 /* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */ 30 /* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */ 31 /* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */ 32 /* PURPOSE. */ 33 34 35 #include "flexdef.h" 36 37 /* ccl2ecl - convert character classes to set of equivalence classes */ 38 ccl2ecl(void)39 void ccl2ecl (void) 40 { 41 int i, ich, newlen, cclp, ccls, cclmec; 42 43 for (i = 1; i <= lastccl; ++i) { 44 /* We loop through each character class, and for each character 45 * in the class, add the character's equivalence class to the 46 * new "character" class we are creating. Thus when we are all 47 * done, character classes will really consist of collections 48 * of equivalence classes 49 */ 50 51 newlen = 0; 52 cclp = cclmap[i]; 53 54 for (ccls = 0; ccls < ccllen[i]; ++ccls) { 55 ich = ccltbl[cclp + ccls]; 56 cclmec = ecgroup[ich]; 57 58 if (cclmec > 0) { 59 /* Note: range 1..256 is mapped to 1..255,0 */ 60 ccltbl[cclp + newlen] = (unsigned char) cclmec; 61 ++newlen; 62 } 63 } 64 65 ccllen[i] = newlen; 66 } 67 } 68 69 70 /* cre8ecs - associate equivalence class numbers with class members 71 * 72 * fwd is the forward linked-list of equivalence class members. bck 73 * is the backward linked-list, and num is the number of class members. 74 * 75 * Returned is the number of classes. 76 */ 77 cre8ecs(int fwd[],int bck[],int num)78 int cre8ecs (int fwd[], int bck[], int num) 79 { 80 int i, j, numcl; 81 82 numcl = 0; 83 84 /* Create equivalence class numbers. From now on, ABS( bck(x) ) 85 * is the equivalence class number for object x. If bck(x) 86 * is positive, then x is the representative of its equivalence 87 * class. 88 */ 89 for (i = 1; i <= num; ++i) 90 if (bck[i] == NIL) { 91 bck[i] = ++numcl; 92 for (j = fwd[i]; j != NIL; j = fwd[j]) 93 bck[j] = -numcl; 94 } 95 96 return numcl; 97 } 98 99 100 /* mkeccl - update equivalence classes based on character class xtions 101 * 102 * synopsis 103 * unsigned char ccls[]; 104 * int lenccl, fwd[llsiz], bck[llsiz], llsiz, NUL_mapping; 105 * void mkeccl( unsigned char ccls[], int lenccl, int fwd[llsiz], int bck[llsiz], 106 * int llsiz, int NUL_mapping ); 107 * 108 * ccls contains the elements of the character class, lenccl is the 109 * number of elements in the ccl, fwd is the forward link-list of equivalent 110 * characters, bck is the backward link-list, and llsiz size of the link-list. 111 * 112 * NUL_mapping is the value which NUL (0) should be mapped to. 113 */ 114 mkeccl(unsigned char ccls[],int lenccl,int fwd[],int bck[],int llsiz,int NUL_mapping)115 void mkeccl (unsigned char ccls[], int lenccl, int fwd[], int bck[], int llsiz, int NUL_mapping) 116 { 117 int cclp, oldec, newec; 118 int cclm, i, j; 119 static unsigned char cclflags[CSIZE]; /* initialized to all '\0' */ 120 121 /* Note that it doesn't matter whether or not the character class is 122 * negated. The same results will be obtained in either case. 123 */ 124 125 cclp = 0; 126 127 while (cclp < lenccl) { 128 cclm = ccls[cclp]; 129 130 if (NUL_mapping && cclm == 0) 131 cclm = NUL_mapping; 132 133 oldec = bck[cclm]; 134 newec = cclm; 135 136 j = cclp + 1; 137 138 for (i = fwd[cclm]; i != NIL && i <= llsiz; i = fwd[i]) { /* look for the symbol in the character class */ 139 for (; j < lenccl; ++j) { 140 int ccl_char; 141 142 if (NUL_mapping && ccls[j] == 0) 143 ccl_char = NUL_mapping; 144 else 145 ccl_char = ccls[j]; 146 147 if (ccl_char > i) 148 break; 149 150 if (ccl_char == i && !cclflags[j]) { 151 /* We found an old companion of cclm 152 * in the ccl. Link it into the new 153 * equivalence class and flag it as 154 * having been processed. 155 */ 156 157 bck[i] = newec; 158 fwd[newec] = i; 159 newec = i; 160 /* Set flag so we don't reprocess. */ 161 cclflags[j] = 1; 162 163 /* Get next equivalence class member. */ 164 /* continue 2 */ 165 goto next_pt; 166 } 167 } 168 169 /* Symbol isn't in character class. Put it in the old 170 * equivalence class. 171 */ 172 173 bck[i] = oldec; 174 175 if (oldec != NIL) 176 fwd[oldec] = i; 177 178 oldec = i; 179 180 next_pt:; 181 } 182 183 if (bck[cclm] != NIL || oldec != bck[cclm]) { 184 bck[cclm] = NIL; 185 fwd[oldec] = NIL; 186 } 187 188 fwd[newec] = NIL; 189 190 /* Find next ccl member to process. */ 191 192 for (++cclp; cclp < lenccl && cclflags[cclp]; ++cclp) { 193 /* Reset "doesn't need processing" flag. */ 194 cclflags[cclp] = 0; 195 } 196 } 197 } 198 199 200 /* mkechar - create equivalence class for single character */ 201 mkechar(int tch,int fwd[],int bck[])202 void mkechar (int tch, int fwd[], int bck[]) 203 { 204 /* If until now the character has been a proper subset of 205 * an equivalence class, break it away to create a new ec 206 */ 207 208 if (fwd[tch] != NIL) 209 bck[fwd[tch]] = bck[tch]; 210 211 if (bck[tch] != NIL) 212 fwd[bck[tch]] = fwd[tch]; 213 214 fwd[tch] = NIL; 215 bck[tch] = NIL; 216 } 217