1 /* ecs - equivalence class routines */
4 * Copyright (c) 1990 The Regents of the University of California.
7 * This code is derived from software contributed to Berkeley by
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11 * to contract no. DE-AC03-76SF00098 between the United States
12 * Department of Energy and the University of California.
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29 /* $Header: /home/daffy/u0/vern/flex/RCS/ecs.c,v 2.9 93/12/07 10:18:20 vern Exp $ */
34 /* ccl2ecl - convert character classes to set of equivalence classes */
38 int i, ich, newlen, cclp, ccls, cclmec;
40 for ( i = 1; i <= lastccl; ++i )
42 /* We loop through each character class, and for each character
43 * in the class, add the character's equivalence class to the
44 * new "character" class we are creating. Thus when we are all
45 * done, character classes will really consist of collections
46 * of equivalence classes
52 for ( ccls = 0; ccls < ccllen[i]; ++ccls )
54 ich = ccltbl[cclp + ccls];
55 cclmec = ecgroup[ich];
59 ccltbl[cclp + newlen] = cclmec;
69 /* cre8ecs - associate equivalence class numbers with class members
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.
74 * Returned is the number of classes.
77 int cre8ecs( fwd, bck, num )
78 int fwd[], bck[], num;
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
89 for ( i = 1; i <= num; ++i )
93 for ( j = fwd[i]; j != NIL; j = fwd[j] )
101 /* mkeccl - update equivalence classes based on character class xtions
105 * int lenccl, fwd[llsiz], bck[llsiz], llsiz, NUL_mapping;
106 * void mkeccl( Char ccls[], int lenccl, int fwd[llsiz], int bck[llsiz],
107 * int llsiz, int NUL_mapping );
109 * ccls contains the elements of the character class, lenccl is the
110 * number of elements in the ccl, fwd is the forward link-list of equivalent
111 * characters, bck is the backward link-list, and llsiz size of the link-list.
113 * NUL_mapping is the value which NUL (0) should be mapped to.
116 void mkeccl( ccls, lenccl, fwd, bck, llsiz, NUL_mapping )
118 int lenccl, fwd[], bck[], llsiz, NUL_mapping;
120 int cclp, oldec, newec;
122 static unsigned char cclflags[CSIZE]; /* initialized to all '\0' */
124 /* Note that it doesn't matter whether or not the character class is
125 * negated. The same results will be obtained in either case.
130 while ( cclp < lenccl )
134 if ( NUL_mapping && cclm == 0 )
142 for ( i = fwd[cclm]; i != NIL && i <= llsiz; i = fwd[i] )
143 { /* look for the symbol in the character class */
144 for ( ; j < lenccl; ++j )
146 register int ccl_char;
148 if ( NUL_mapping && ccls[j] == 0 )
149 ccl_char = NUL_mapping;
156 if ( ccl_char == i && ! cclflags[j] )
158 /* We found an old companion of cclm
159 * in the ccl. Link it into the new
160 * equivalence class and flag it as
161 * having been processed.
167 /* Set flag so we don't reprocess. */
170 /* Get next equivalence class member. */
176 /* Symbol isn't in character class. Put it in the old
190 if ( bck[cclm] != NIL || oldec != bck[cclm] )
198 /* Find next ccl member to process. */
200 for ( ++cclp; cclflags[cclp] && cclp < lenccl; ++cclp )
202 /* Reset "doesn't need processing" flag. */
209 /* mkechar - create equivalence class for single character */
211 void mkechar( tch, fwd, bck )
212 int tch, fwd[], bck[];
214 /* If until now the character has been a proper subset of
215 * an equivalence class, break it away to create a new ec
218 if ( fwd[tch] != NIL )
219 bck[fwd[tch]] = bck[tch];
221 if ( bck[tch] != NIL )
222 fwd[bck[tch]] = fwd[tch];