350 lines
8.5 KiB
C
350 lines
8.5 KiB
C
/* ecs - equivalence class routines */
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/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Vern Paxson.
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*
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* The United States Government has rights in this work pursuant
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* to contract no. DE-AC03-76SF00098 between the United States
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* Department of Energy and the University of California.
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*
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* Redistribution and use in source and binary forms are permitted provided
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* that: (1) source distributions retain this entire copyright notice and
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* comment, and (2) distributions including binaries display the following
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* acknowledgement: ``This product includes software developed by the
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* University of California, Berkeley and its contributors'' in the
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* documentation or other materials provided with the distribution and in
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* all advertising materials mentioning features or use of this software.
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* Neither the name of the University nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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static char rcsid[] =
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"@(#) $Header$ (LBL)";
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#endif
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#include "flexdef.h"
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/* ccl2ecl - convert character classes to set of equivalence classes
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*
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* synopsis
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* ccl2ecl();
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*/
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void ccl2ecl()
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{
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int i, ich, newlen, cclp, ccls, cclmec;
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for ( i = 1; i <= lastccl; ++i )
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{
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/* we loop through each character class, and for each character
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* in the class, add the character's equivalence class to the
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* new "character" class we are creating. Thus when we are all
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* done, character classes will really consist of collections
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* of equivalence classes
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*/
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newlen = 0;
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cclp = cclmap[i];
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for ( ccls = 0; ccls < ccllen[i]; ++ccls )
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{
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ich = ccltbl[cclp + ccls];
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cclmec = ecgroup[ich];
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if ( xlation && cclmec < 0 )
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{
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/* special hack--if we're doing %t tables then it's
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* possible that no representative of this character's
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* equivalence class is in the ccl. So waiting till
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* we see the representative would be disastrous. Instead,
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* we add this character's equivalence class anyway, if it's
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* not already present.
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*/
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int j;
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/* this loop makes this whole process n^2; but we don't
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* really care about %t performance anyway
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*/
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for ( j = 0; j < newlen; ++j )
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if ( ccltbl[cclp + j] == -cclmec )
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break;
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if ( j >= newlen )
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{ /* no representative yet, add this one in */
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ccltbl[cclp + newlen] = -cclmec;
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++newlen;
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}
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}
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else if ( cclmec > 0 )
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{
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ccltbl[cclp + newlen] = cclmec;
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++newlen;
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}
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}
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ccllen[i] = newlen;
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}
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}
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/* cre8ecs - associate equivalence class numbers with class members
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*
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* synopsis
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* int cre8ecs();
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* number of classes = cre8ecs( fwd, bck, num );
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*
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* fwd is the forward linked-list of equivalence class members. bck
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* is the backward linked-list, and num is the number of class members.
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*
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* Returned is the number of classes.
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*/
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int cre8ecs( fwd, bck, num )
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int fwd[], bck[], num;
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{
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int i, j, numcl;
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numcl = 0;
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/* create equivalence class numbers. From now on, abs( bck(x) )
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* is the equivalence class number for object x. If bck(x)
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* is positive, then x is the representative of its equivalence
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* class.
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*/
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for ( i = 1; i <= num; ++i )
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if ( bck[i] == NIL )
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{
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bck[i] = ++numcl;
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for ( j = fwd[i]; j != NIL; j = fwd[j] )
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bck[j] = -numcl;
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}
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return ( numcl );
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}
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/* ecs_from_xlation - associate equivalence class numbers using %t table
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*
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* synopsis
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* numecs = ecs_from_xlation( ecmap );
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*
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* Upon return, ecmap will map each character code to its equivalence
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* class. The mapping will be positive if the character is the representative
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* of its class, negative otherwise.
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*
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* Returns the number of equivalence classes used.
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*/
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int ecs_from_xlation( ecmap )
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int ecmap[];
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{
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int i;
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int nul_is_alone = false;
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int did_default_xlation_class = false;
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if ( xlation[0] != 0 )
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{
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/* if NUL shares its translation with other characters, choose one
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* of the other characters as the representative for the equivalence
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* class. This allows a cheap test later to see whether we can
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* do away with NUL's equivalence class.
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*/
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for ( i = 1; i < csize; ++i )
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if ( xlation[i] == -xlation[0] )
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{
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xlation[i] = xlation[0];
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ecmap[0] = -xlation[0];
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break;
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}
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if ( i >= csize )
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/* didn't find a companion character--remember this fact */
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nul_is_alone = true;
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}
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for ( i = 1; i < csize; ++i )
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if ( xlation[i] == 0 )
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{
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if ( did_default_xlation_class )
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ecmap[i] = -num_xlations;
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else
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{
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/* make an equivalence class for those characters not
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* specified in the %t table
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*/
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++num_xlations;
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ecmap[i] = num_xlations;
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did_default_xlation_class = true;
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}
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}
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else
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ecmap[i] = xlation[i];
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if ( nul_is_alone )
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/* force NUL's equivalence class to be the last one */
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{
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++num_xlations;
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ecmap[0] = num_xlations;
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/* there's actually a bug here: if someone is fanatic enough to
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* put every character in its own translation class, then right
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* now we just promoted NUL's equivalence class to be csize + 1;
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* we can handle NUL's class number being == csize (by instead
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* putting it in its own table), but we can't handle some *other*
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* character having to be put in its own table, too. So in
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* this case we bail out.
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*/
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if ( num_xlations > csize )
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flexfatal( "too many %t classes!" );
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}
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return num_xlations;
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}
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/* mkeccl - update equivalence classes based on character class xtions
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*
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* synopsis
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* Char ccls[];
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* int lenccl, fwd[llsiz], bck[llsiz], llsiz, NUL_mapping;
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* mkeccl( ccls, lenccl, fwd, bck, llsiz, NUL_mapping );
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*
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* where ccls contains the elements of the character class, lenccl is the
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* number of elements in the ccl, fwd is the forward link-list of equivalent
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* characters, bck is the backward link-list, and llsiz size of the link-list
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*
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* NUL_mapping is the value which NUL (0) should be mapped to.
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*/
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void mkeccl( ccls, lenccl, fwd, bck, llsiz, NUL_mapping )
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Char ccls[];
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int lenccl, fwd[], bck[], llsiz, NUL_mapping;
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{
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int cclp, oldec, newec;
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int cclm, i, j;
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static unsigned char cclflags[CSIZE]; /* initialized to all '\0' */
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/* note that it doesn't matter whether or not the character class is
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* negated. The same results will be obtained in either case.
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*/
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cclp = 0;
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while ( cclp < lenccl )
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{
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cclm = ccls[cclp];
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if ( NUL_mapping && cclm == 0 )
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cclm = NUL_mapping;
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oldec = bck[cclm];
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newec = cclm;
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j = cclp + 1;
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for ( i = fwd[cclm]; i != NIL && i <= llsiz; i = fwd[i] )
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{ /* look for the symbol in the character class */
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for ( ; j < lenccl; ++j )
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{
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register int ccl_char;
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if ( NUL_mapping && ccls[j] == 0 )
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ccl_char = NUL_mapping;
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else
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ccl_char = ccls[j];
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if ( ccl_char > i )
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break;
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if ( ccl_char == i && ! cclflags[j] )
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{
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/* we found an old companion of cclm in the ccl.
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* link it into the new equivalence class and flag it as
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* having been processed
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*/
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bck[i] = newec;
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fwd[newec] = i;
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newec = i;
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cclflags[j] = 1; /* set flag so we don't reprocess */
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/* get next equivalence class member */
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/* continue 2 */
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goto next_pt;
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}
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}
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/* symbol isn't in character class. Put it in the old equivalence
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* class
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*/
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bck[i] = oldec;
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if ( oldec != NIL )
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fwd[oldec] = i;
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oldec = i;
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next_pt:
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;
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}
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if ( bck[cclm] != NIL || oldec != bck[cclm] )
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{
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bck[cclm] = NIL;
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fwd[oldec] = NIL;
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}
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fwd[newec] = NIL;
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/* find next ccl member to process */
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for ( ++cclp; cclflags[cclp] && cclp < lenccl; ++cclp )
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{
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/* reset "doesn't need processing" flag */
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cclflags[cclp] = 0;
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}
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}
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}
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/* mkechar - create equivalence class for single character
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*
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* synopsis
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* int tch, fwd[], bck[];
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* mkechar( tch, fwd, bck );
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*/
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void mkechar( tch, fwd, bck )
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int tch, fwd[], bck[];
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{
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/* if until now the character has been a proper subset of
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* an equivalence class, break it away to create a new ec
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*/
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if ( fwd[tch] != NIL )
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bck[fwd[tch]] = bck[tch];
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if ( bck[tch] != NIL )
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fwd[bck[tch]] = fwd[tch];
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fwd[tch] = NIL;
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bck[tch] = NIL;
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}
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