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 #include "flexdef.h" 34 __RCSID("$NetBSD: ecs.c,v 1.3 2017/01/02 17:45:27 christos Exp $"); 35 36 /* ccl2ecl - convert character classes to set of equivalence classes */ 37 38 void ccl2ecl (void) 39 { 40 int i, ich, newlen, cclp, ccls, cclmec; 41 42 for (i = 1; i <= lastccl; ++i) { 43 /* We loop through each character class, and for each character 44 * in the class, add the character's equivalence class to the 45 * new "character" class we are creating. Thus when we are all 46 * done, character classes will really consist of collections 47 * of equivalence classes 48 */ 49 50 newlen = 0; 51 cclp = cclmap[i]; 52 53 for (ccls = 0; ccls < ccllen[i]; ++ccls) { 54 ich = ccltbl[cclp + ccls]; 55 cclmec = ecgroup[ich]; 56 57 if (cclmec > 0) { 58 /* Note: range 1..256 is mapped to 1..255,0 */ 59 ccltbl[cclp + newlen] = (unsigned char) cclmec; 60 ++newlen; 61 } 62 } 63 64 ccllen[i] = newlen; 65 } 66 } 67 68 69 /* cre8ecs - associate equivalence class numbers with class members 70 * 71 * fwd is the forward linked-list of equivalence class members. bck 72 * is the backward linked-list, and num is the number of class members. 73 * 74 * Returned is the number of classes. 75 */ 76 77 int cre8ecs (int fwd[], int bck[], int num) 78 { 79 int i, j, numcl; 80 81 numcl = 0; 82 83 /* Create equivalence class numbers. From now on, ABS( bck(x) ) 84 * is the equivalence class number for object x. If bck(x) 85 * is positive, then x is the representative of its equivalence 86 * class. 87 */ 88 for (i = 1; i <= num; ++i) 89 if (bck[i] == NIL) { 90 bck[i] = ++numcl; 91 for (j = fwd[i]; j != NIL; j = fwd[j]) 92 bck[j] = -numcl; 93 } 94 95 return numcl; 96 } 97 98 99 /* mkeccl - update equivalence classes based on character class xtions 100 * 101 * synopsis 102 * unsigned char ccls[]; 103 * int lenccl, fwd[llsiz], bck[llsiz], llsiz, NUL_mapping; 104 * void mkeccl( unsigned char ccls[], int lenccl, int fwd[llsiz], int bck[llsiz], 105 * int llsiz, int NUL_mapping ); 106 * 107 * ccls contains the elements of the character class, lenccl is the 108 * number of elements in the ccl, fwd is the forward link-list of equivalent 109 * characters, bck is the backward link-list, and llsiz size of the link-list. 110 * 111 * NUL_mapping is the value which NUL (0) should be mapped to. 112 */ 113 114 void mkeccl (unsigned char ccls[], int lenccl, int fwd[], int bck[], int llsiz, int NUL_mapping) 115 { 116 int cclp, oldec, newec; 117 int cclm, i, j; 118 static unsigned char cclflags[CSIZE]; /* initialized to all '\0' */ 119 120 /* Note that it doesn't matter whether or not the character class is 121 * negated. The same results will be obtained in either case. 122 */ 123 124 cclp = 0; 125 126 while (cclp < lenccl) { 127 cclm = ccls[cclp]; 128 129 if (NUL_mapping && cclm == 0) 130 cclm = NUL_mapping; 131 132 oldec = bck[cclm]; 133 newec = cclm; 134 135 j = cclp + 1; 136 137 for (i = fwd[cclm]; i != NIL && i <= llsiz; i = fwd[i]) { /* look for the symbol in the character class */ 138 for (; j < lenccl; ++j) { 139 int ccl_char; 140 141 if (NUL_mapping && ccls[j] == 0) 142 ccl_char = NUL_mapping; 143 else 144 ccl_char = ccls[j]; 145 146 if (ccl_char > i) 147 break; 148 149 if (ccl_char == i && !cclflags[j]) { 150 /* We found an old companion of cclm 151 * in the ccl. Link it into the new 152 * equivalence class and flag it as 153 * having been processed. 154 */ 155 156 bck[i] = newec; 157 fwd[newec] = i; 158 newec = i; 159 /* Set flag so we don't reprocess. */ 160 cclflags[j] = 1; 161 162 /* Get next equivalence class member. */ 163 /* continue 2 */ 164 goto next_pt; 165 } 166 } 167 168 /* Symbol isn't in character class. Put it in the old 169 * equivalence class. 170 */ 171 172 bck[i] = oldec; 173 174 if (oldec != NIL) 175 fwd[oldec] = i; 176 177 oldec = i; 178 179 next_pt:; 180 } 181 182 if (bck[cclm] != NIL || oldec != bck[cclm]) { 183 bck[cclm] = NIL; 184 fwd[oldec] = NIL; 185 } 186 187 fwd[newec] = NIL; 188 189 /* Find next ccl member to process. */ 190 191 for (++cclp; cclp < lenccl && cclflags[cclp]; ++cclp) { 192 /* Reset "doesn't need processing" flag. */ 193 cclflags[cclp] = 0; 194 } 195 } 196 } 197 198 199 /* mkechar - create equivalence class for single character */ 200 201 void mkechar (int tch, int fwd[], int bck[]) 202 { 203 /* If until now the character has been a proper subset of 204 * an equivalence class, break it away to create a new ec 205 */ 206 207 if (fwd[tch] != NIL) 208 bck[fwd[tch]] = bck[tch]; 209 210 if (bck[tch] != NIL) 211 fwd[bck[tch]] = fwd[tch]; 212 213 fwd[tch] = NIL; 214 bck[tch] = NIL; 215 } 216
Indexes created Sat Jul 04 00:25:45 UTC 2026