697 lines
12 KiB
C
697 lines
12 KiB
C
/* $NetBSD: lalr.c,v 1.11 2009/04/14 09:41:30 lukem Exp $ */
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/*
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* Copyright (c) 1989 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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* Robert Paul Corbett.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(__RCSID) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)lalr.c 5.3 (Berkeley) 6/1/90";
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#else
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__RCSID("$NetBSD: lalr.c,v 1.11 2009/04/14 09:41:30 lukem Exp $");
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#endif
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#endif /* not lint */
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#include "defs.h"
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typedef
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struct shorts
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{
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struct shorts *next;
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short value;
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}
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shorts;
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short *lookaheads;
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short *LAruleno;
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unsigned *LA;
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short *accessing_symbol;
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core **state_table;
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shifts **shift_table;
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reductions **reduction_table;
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short *goto_map;
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short *from_state;
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short *to_state;
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static int tokensetsize;
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static short **transpose(short **, int);
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static void set_state_table(void);
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static void set_accessing_symbol(void);
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static void set_shift_table(void);
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static void set_reduction_table(void);
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static void set_maxrhs(void);
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static void initialize_LA(void);
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static void set_goto_map(void);
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static void initialize_F(void);
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static void build_relations(void);
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static void compute_FOLLOWS(void);
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static void compute_lookaheads(void);
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static int map_goto(int, int);
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static void digraph(short **);
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static void add_lookback_edge(int, int, int);
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static void traverse(int);
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static int infinity;
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static int maxrhs;
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static int ngotos;
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static unsigned *F;
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static short **includes;
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static shorts **lookback;
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static short **R;
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static short *INDEX;
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static short *VERTICES;
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static int top;
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void
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lalr(void)
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{
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tokensetsize = WORDSIZE(ntokens);
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set_state_table();
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set_accessing_symbol();
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set_shift_table();
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set_reduction_table();
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set_maxrhs();
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initialize_LA();
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set_goto_map();
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initialize_F();
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build_relations();
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compute_FOLLOWS();
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compute_lookaheads();
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}
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static void
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set_state_table(void)
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{
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core *sp;
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state_table = NEW2(nstates, core *);
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for (sp = first_state; sp; sp = sp->next)
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state_table[sp->number] = sp;
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}
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static void
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set_accessing_symbol(void)
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{
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core *sp;
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accessing_symbol = NEW2(nstates, short);
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for (sp = first_state; sp; sp = sp->next)
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accessing_symbol[sp->number] = sp->accessing_symbol;
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}
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static void
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set_shift_table(void)
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{
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shifts *sp;
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shift_table = NEW2(nstates, shifts *);
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for (sp = first_shift; sp; sp = sp->next)
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shift_table[sp->number] = sp;
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}
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static void
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set_reduction_table(void)
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{
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reductions *rp;
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reduction_table = NEW2(nstates, reductions *);
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for (rp = first_reduction; rp; rp = rp->next)
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reduction_table[rp->number] = rp;
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}
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static void
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set_maxrhs(void)
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{
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short *itemp;
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short *item_end;
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int length;
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int max;
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length = 0;
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max = 0;
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item_end = ritem + nitems;
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for (itemp = ritem; itemp < item_end; itemp++)
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{
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if (*itemp >= 0)
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{
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length++;
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}
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else
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{
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if (length > max) max = length;
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length = 0;
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}
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}
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maxrhs = max;
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}
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static void
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initialize_LA(void)
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{
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int i, j, k;
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reductions *rp;
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lookaheads = NEW2(nstates + 1, short);
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k = 0;
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for (i = 0; i < nstates; i++)
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{
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lookaheads[i] = k;
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rp = reduction_table[i];
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if (rp)
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k += rp->nreds;
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}
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lookaheads[nstates] = k;
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LA = NEW2(k * tokensetsize, unsigned);
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LAruleno = NEW2(k, short);
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lookback = NEW2(k, shorts *);
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k = 0;
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for (i = 0; i < nstates; i++)
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{
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rp = reduction_table[i];
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if (rp)
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{
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for (j = 0; j < rp->nreds; j++)
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{
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LAruleno[k] = rp->rules[j];
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k++;
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}
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}
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}
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}
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static void
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set_goto_map(void)
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{
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shifts *sp;
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int i;
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int symbol;
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int k;
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short *temp_map;
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int state2;
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int state1;
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goto_map = NEW2(nvars + 1, short) - ntokens;
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temp_map = NEW2(nvars + 1, short) - ntokens;
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ngotos = 0;
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for (sp = first_shift; sp; sp = sp->next)
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{
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for (i = sp->nshifts - 1; i >= 0; i--)
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{
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symbol = accessing_symbol[sp->shift[i]];
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if (ISTOKEN(symbol)) break;
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if (ngotos == MAXSHORT)
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fatal("too many gotos");
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ngotos++;
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goto_map[symbol]++;
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}
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}
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k = 0;
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for (i = ntokens; i < nsyms; i++)
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{
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temp_map[i] = k;
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k += goto_map[i];
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}
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for (i = ntokens; i < nsyms; i++)
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goto_map[i] = temp_map[i];
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goto_map[nsyms] = ngotos;
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temp_map[nsyms] = ngotos;
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from_state = NEW2(ngotos, short);
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to_state = NEW2(ngotos, short);
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for (sp = first_shift; sp; sp = sp->next)
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{
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state1 = sp->number;
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for (i = sp->nshifts - 1; i >= 0; i--)
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{
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state2 = sp->shift[i];
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symbol = accessing_symbol[state2];
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if (ISTOKEN(symbol)) break;
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k = temp_map[symbol]++;
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from_state[k] = state1;
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to_state[k] = state2;
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}
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}
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FREE(temp_map + ntokens);
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}
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/* Map_goto maps a state/symbol pair into its numeric representation. */
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static int
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map_goto(int state, int symbol)
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{
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int high;
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int low;
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int middle;
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int s;
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low = goto_map[symbol];
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high = goto_map[symbol + 1];
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for (;;)
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{
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assert(low <= high);
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middle = (low + high) >> 1;
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s = from_state[middle];
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if (s == state)
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return (middle);
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else if (s < state)
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low = middle + 1;
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else
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high = middle - 1;
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}
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}
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static void
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initialize_F(void)
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{
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int i;
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int j;
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int k;
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shifts *sp;
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short *edge;
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unsigned *rowp;
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short *rp;
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short **reads;
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int nedges;
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int stateno;
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int symbol;
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int nwords;
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nwords = ngotos * tokensetsize;
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F = NEW2(nwords, unsigned);
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reads = NEW2(ngotos, short *);
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edge = NEW2(ngotos + 1, short);
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nedges = 0;
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rowp = F;
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for (i = 0; i < ngotos; i++)
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{
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stateno = to_state[i];
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sp = shift_table[stateno];
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if (sp)
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{
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k = sp->nshifts;
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for (j = 0; j < k; j++)
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{
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symbol = accessing_symbol[sp->shift[j]];
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if (ISVAR(symbol))
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break;
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SETBIT(rowp, symbol);
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}
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for (; j < k; j++)
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{
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symbol = accessing_symbol[sp->shift[j]];
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if (nullable[symbol])
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edge[nedges++] = map_goto(stateno, symbol);
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}
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if (nedges)
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{
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reads[i] = rp = NEW2(nedges + 1, short);
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for (j = 0; j < nedges; j++)
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rp[j] = edge[j];
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rp[nedges] = -1;
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nedges = 0;
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}
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}
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rowp += tokensetsize;
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}
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SETBIT(F, 0);
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digraph(reads);
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for (i = 0; i < ngotos; i++)
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{
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if (reads[i])
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FREE(reads[i]);
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}
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FREE(reads);
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FREE(edge);
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}
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static void
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build_relations(void)
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{
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int i;
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int j;
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int k;
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short *rulep;
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short *rp;
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shifts *sp;
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int length;
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int nedges;
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int isdone;
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int state1;
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int stateno;
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int symbol1;
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int symbol2;
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short *shortp;
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short *edge;
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short *states;
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short **new_includes;
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includes = NEW2(ngotos, short *);
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edge = NEW2(ngotos + 1, short);
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states = NEW2(maxrhs + 1, short);
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for (i = 0; i < ngotos; i++)
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{
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nedges = 0;
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state1 = from_state[i];
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symbol1 = accessing_symbol[to_state[i]];
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for (rulep = derives[symbol1]; *rulep >= 0; rulep++)
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{
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length = 1;
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states[0] = state1;
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stateno = state1;
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for (rp = ritem + rrhs[*rulep]; *rp >= 0; rp++)
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{
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symbol2 = *rp;
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sp = shift_table[stateno];
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k = sp->nshifts;
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for (j = 0; j < k; j++)
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{
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stateno = sp->shift[j];
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if (accessing_symbol[stateno] == symbol2) break;
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}
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states[length++] = stateno;
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}
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add_lookback_edge(stateno, *rulep, i);
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length--;
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isdone = 0;
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while (!isdone)
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{
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isdone = 1;
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rp--;
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if (ISVAR(*rp))
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{
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stateno = states[--length];
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edge[nedges++] = map_goto(stateno, *rp);
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if (nullable[*rp] && length > 0) isdone = 0;
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}
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}
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}
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if (nedges)
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{
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includes[i] = shortp = NEW2(nedges + 1, short);
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for (j = 0; j < nedges; j++)
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shortp[j] = edge[j];
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shortp[nedges] = -1;
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}
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}
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new_includes = transpose(includes, ngotos);
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for (i = 0; i < ngotos; i++)
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if (includes[i])
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FREE(includes[i]);
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FREE(includes);
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includes = new_includes;
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FREE(edge);
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FREE(states);
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}
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static void
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add_lookback_edge(int stateno, int ruleno, int gotono)
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{
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int i, k;
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int found;
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shorts *sp;
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i = lookaheads[stateno];
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k = lookaheads[stateno + 1];
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found = 0;
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while (!found && i < k)
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{
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if (LAruleno[i] == ruleno)
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found = 1;
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else
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++i;
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}
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assert(found);
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sp = NEW(shorts);
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sp->next = lookback[i];
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sp->value = gotono;
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lookback[i] = sp;
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}
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static short **
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transpose(short **tR, int n)
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{
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short **new_R;
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short **temp_R;
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short *nedges;
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short *sp;
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int i;
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int k;
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nedges = NEW2(n, short);
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for (i = 0; i < n; i++)
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{
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sp = tR[i];
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if (sp)
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{
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while (*sp >= 0)
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nedges[*sp++]++;
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}
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}
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new_R = NEW2(n, short *);
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temp_R = NEW2(n, short *);
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for (i = 0; i < n; i++)
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{
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k = nedges[i];
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if (k > 0)
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{
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sp = NEW2(k + 1, short);
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new_R[i] = sp;
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temp_R[i] = sp;
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sp[k] = -1;
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}
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}
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FREE(nedges);
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for (i = 0; i < n; i++)
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{
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sp = tR[i];
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if (sp)
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{
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while (*sp >= 0)
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*temp_R[*sp++]++ = i;
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}
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}
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FREE(temp_R);
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return (new_R);
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}
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static void
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compute_FOLLOWS(void)
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{
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digraph(includes);
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}
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static void
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compute_lookaheads(void)
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{
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int i, n;
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unsigned *fp1, *fp2, *fp3;
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shorts *sp, *next;
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unsigned *rowp;
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rowp = LA;
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n = lookaheads[nstates];
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for (i = 0; i < n; i++)
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{
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fp3 = rowp + tokensetsize;
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for (sp = lookback[i]; sp; sp = sp->next)
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{
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fp1 = rowp;
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fp2 = F + tokensetsize * sp->value;
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while (fp1 < fp3)
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*fp1++ |= *fp2++;
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}
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rowp = fp3;
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}
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for (i = 0; i < n; i++)
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for (sp = lookback[i]; sp; sp = next)
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{
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next = sp->next;
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FREE(sp);
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}
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FREE(lookback);
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FREE(F);
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}
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static void
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digraph(short **relation)
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{
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int i;
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infinity = ngotos + 2;
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INDEX = NEW2(ngotos + 1, short);
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VERTICES = NEW2(ngotos + 1, short);
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top = 0;
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R = relation;
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|
for (i = 0; i < ngotos; i++)
|
|
INDEX[i] = 0;
|
|
|
|
for (i = 0; i < ngotos; i++)
|
|
{
|
|
if (INDEX[i] == 0 && R[i])
|
|
traverse(i);
|
|
}
|
|
|
|
FREE(INDEX);
|
|
FREE(VERTICES);
|
|
}
|
|
|
|
|
|
static void
|
|
traverse(int i)
|
|
{
|
|
unsigned *fp1;
|
|
unsigned *fp2;
|
|
unsigned *fp3;
|
|
int j;
|
|
short *rp;
|
|
|
|
int height;
|
|
unsigned *base;
|
|
|
|
VERTICES[++top] = i;
|
|
INDEX[i] = height = top;
|
|
|
|
base = F + i * tokensetsize;
|
|
fp3 = base + tokensetsize;
|
|
|
|
rp = R[i];
|
|
if (rp)
|
|
{
|
|
while ((j = *rp++) >= 0)
|
|
{
|
|
if (INDEX[j] == 0)
|
|
traverse(j);
|
|
|
|
if (INDEX[i] > INDEX[j])
|
|
INDEX[i] = INDEX[j];
|
|
|
|
fp1 = base;
|
|
fp2 = F + j * tokensetsize;
|
|
|
|
while (fp1 < fp3)
|
|
*fp1++ |= *fp2++;
|
|
}
|
|
}
|
|
|
|
if (INDEX[i] == height)
|
|
{
|
|
for (;;)
|
|
{
|
|
j = VERTICES[top--];
|
|
INDEX[j] = infinity;
|
|
|
|
if (i == j)
|
|
break;
|
|
|
|
fp1 = base;
|
|
fp2 = F + j * tokensetsize;
|
|
|
|
while (fp1 < fp3)
|
|
*fp2++ = *fp1++;
|
|
}
|
|
}
|
|
}
|