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
10 * The United States Government has rights in this work pursuant
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 $ */
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
35 /* ccl2ecl - convert character classes to set of equivalence classes */
39 int i, ich, newlen, cclp, ccls, cclmec;
41 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
53 for ( ccls = 0; ccls < ccllen[i]; ++ccls )
55 ich = ccltbl[cclp + ccls];
56 cclmec = ecgroup[ich];
60 ccltbl[cclp + newlen] = cclmec;
70 /* cre8ecs - associate equivalence class numbers with class members
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.
75 * Returned is the number of classes.
78 int cre8ecs( fwd, bck, num )
79 int fwd[], bck[], num;
85 /* Create equivalence class numbers. From now on, ABS( bck(x) )
86 * is the equivalence class number for object x. If bck(x)
87 * is positive, then x is the representative of its equivalence
90 for ( i = 1; i <= num; ++i )
94 for ( j = fwd[i]; j != NIL; j = fwd[j] )
102 /* mkeccl - update equivalence classes based on character class xtions
106 * int lenccl, fwd[llsiz], bck[llsiz], llsiz, NUL_mapping;
107 * void mkeccl( Char ccls[], int lenccl, int fwd[llsiz], int bck[llsiz],
108 * int llsiz, int NUL_mapping );
110 * ccls contains the elements of the character class, lenccl is the
111 * number of elements in the ccl, fwd is the forward link-list of equivalent
112 * characters, bck is the backward link-list, and llsiz size of the link-list.
114 * NUL_mapping is the value which NUL (0) should be mapped to.
117 void mkeccl( ccls, lenccl, fwd, bck, llsiz, NUL_mapping )
119 int lenccl, fwd[], bck[], llsiz, NUL_mapping;
121 int cclp, oldec, newec;
123 static unsigned char cclflags[CSIZE]; /* initialized to all '\0' */
125 /* Note that it doesn't matter whether or not the character class is
126 * negated. The same results will be obtained in either case.
131 while ( cclp < lenccl )
135 if ( NUL_mapping && cclm == 0 )
143 for ( i = fwd[cclm]; i != NIL && i <= llsiz; i = fwd[i] )
144 { /* look for the symbol in the character class */
145 for ( ; j < lenccl; ++j )
149 if ( NUL_mapping && ccls[j] == 0 )
150 ccl_char = NUL_mapping;
157 if ( ccl_char == i && ! cclflags[j] )
159 /* We found an old companion of cclm
160 * in the ccl. Link it into the new
161 * equivalence class and flag it as
162 * having been processed.
168 /* Set flag so we don't reprocess. */
171 /* Get next equivalence class member. */
177 /* Symbol isn't in character class. Put it in the old
191 if ( bck[cclm] != NIL || oldec != bck[cclm] )
199 /* Find next ccl member to process. */
201 for ( ++cclp; cclflags[cclp] && cclp < lenccl; ++cclp )
203 /* Reset "doesn't need processing" flag. */
210 /* mkechar - create equivalence class for single character */
212 void mkechar( tch, fwd, bck )
213 int tch, fwd[], bck[];
215 /* If until now the character has been a proper subset of
216 * an equivalence class, break it away to create a new ec
219 if ( fwd[tch] != NIL )
220 bck[fwd[tch]] = bck[tch];
222 if ( bck[tch] != NIL )
223 fwd[bck[tch]] = fwd[tch];