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+/* tblcmp - table compression routines */
+
+/*-
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Vern Paxson.
+ *
+ * The United States Government has rights in this work pursuant
+ * to contract no. DE-AC03-76SF00098 between the United States
+ * Department of Energy and the University of California.
+ *
+ * Redistribution and use in source and binary forms with or without
+ * modification are permitted provided that: (1) source distributions retain
+ * this entire copyright notice and comment, and (2) distributions including
+ * binaries display the following acknowledgement: ``This product includes
+ * software developed by the University of California, Berkeley and its
+ * contributors'' in the documentation or other materials provided with the
+ * distribution and in all advertising materials mentioning features or use
+ * of this software. Neither the name of the University nor the names of
+ * its contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+/* $Header: /home/daffy/u0/vern/flex/RCS/tblcmp.c,v 2.11 94/11/05 17:08:28 vern Exp $ */
+
+#include "flexdef.h"
+
+
+/* declarations for functions that have forward references */
+
+void mkentry PROTO((register int*, int, int, int, int));
+void mkprot PROTO((int[], int, int));
+void mktemplate PROTO((int[], int, int));
+void mv2front PROTO((int));
+int tbldiff PROTO((int[], int, int[]));
+
+
+/* bldtbl - build table entries for dfa state
+ *
+ * synopsis
+ * int state[numecs], statenum, totaltrans, comstate, comfreq;
+ * bldtbl( state, statenum, totaltrans, comstate, comfreq );
+ *
+ * State is the statenum'th dfa state. It is indexed by equivalence class and
+ * gives the number of the state to enter for a given equivalence class.
+ * totaltrans is the total number of transitions out of the state. Comstate
+ * is that state which is the destination of the most transitions out of State.
+ * Comfreq is how many transitions there are out of State to Comstate.
+ *
+ * A note on terminology:
+ * "protos" are transition tables which have a high probability of
+ * either being redundant (a state processed later will have an identical
+ * transition table) or nearly redundant (a state processed later will have
+ * many of the same out-transitions). A "most recently used" queue of
+ * protos is kept around with the hope that most states will find a proto
+ * which is similar enough to be usable, and therefore compacting the
+ * output tables.
+ * "templates" are a special type of proto. If a transition table is
+ * homogeneous or nearly homogeneous (all transitions go to the same
+ * destination) then the odds are good that future states will also go
+ * to the same destination state on basically the same character set.
+ * These homogeneous states are so common when dealing with large rule
+ * sets that they merit special attention. If the transition table were
+ * simply made into a proto, then (typically) each subsequent, similar
+ * state will differ from the proto for two out-transitions. One of these
+ * out-transitions will be that character on which the proto does not go
+ * to the common destination, and one will be that character on which the
+ * state does not go to the common destination. Templates, on the other
+ * hand, go to the common state on EVERY transition character, and therefore
+ * cost only one difference.
+ */
+
+void bldtbl( state, statenum, totaltrans, comstate, comfreq )
+int state[], statenum, totaltrans, comstate, comfreq;
+ {
+ int extptr, extrct[2][CSIZE + 1];
+ int mindiff, minprot, i, d;
+
+ /* If extptr is 0 then the first array of extrct holds the result
+ * of the "best difference" to date, which is those transitions
+ * which occur in "state" but not in the proto which, to date,
+ * has the fewest differences between itself and "state". If
+ * extptr is 1 then the second array of extrct hold the best
+ * difference. The two arrays are toggled between so that the
+ * best difference to date can be kept around and also a difference
+ * just created by checking against a candidate "best" proto.
+ */
+
+ extptr = 0;
+
+ /* If the state has too few out-transitions, don't bother trying to
+ * compact its tables.
+ */
+
+ if ( (totaltrans * 100) < (numecs * PROTO_SIZE_PERCENTAGE) )
+ mkentry( state, numecs, statenum, JAMSTATE, totaltrans );
+
+ else
+ {
+ /* "checkcom" is true if we should only check "state" against
+ * protos which have the same "comstate" value.
+ */
+ int checkcom =
+ comfreq * 100 > totaltrans * CHECK_COM_PERCENTAGE;
+
+ minprot = firstprot;
+ mindiff = totaltrans;
+
+ if ( checkcom )
+ {
+ /* Find first proto which has the same "comstate". */
+ for ( i = firstprot; i != NIL; i = protnext[i] )
+ if ( protcomst[i] == comstate )
+ {
+ minprot = i;
+ mindiff = tbldiff( state, minprot,
+ extrct[extptr] );
+ break;
+ }
+ }
+
+ else
+ {
+ /* Since we've decided that the most common destination
+ * out of "state" does not occur with a high enough
+ * frequency, we set the "comstate" to zero, assuring
+ * that if this state is entered into the proto list,
+ * it will not be considered a template.
+ */
+ comstate = 0;
+
+ if ( firstprot != NIL )
+ {
+ minprot = firstprot;
+ mindiff = tbldiff( state, minprot,
+ extrct[extptr] );
+ }
+ }
+
+ /* We now have the first interesting proto in "minprot". If
+ * it matches within the tolerances set for the first proto,
+ * we don't want to bother scanning the rest of the proto list
+ * to see if we have any other reasonable matches.
+ */
+
+ if ( mindiff * 100 > totaltrans * FIRST_MATCH_DIFF_PERCENTAGE )
+ {
+ /* Not a good enough match. Scan the rest of the
+ * protos.
+ */
+ for ( i = minprot; i != NIL; i = protnext[i] )
+ {
+ d = tbldiff( state, i, extrct[1 - extptr] );
+ if ( d < mindiff )
+ {
+ extptr = 1 - extptr;
+ mindiff = d;
+ minprot = i;
+ }
+ }
+ }
+
+ /* Check if the proto we've decided on as our best bet is close
+ * enough to the state we want to match to be usable.
+ */
+
+ if ( mindiff * 100 > totaltrans * ACCEPTABLE_DIFF_PERCENTAGE )
+ {
+ /* No good. If the state is homogeneous enough,
+ * we make a template out of it. Otherwise, we
+ * make a proto.
+ */
+
+ if ( comfreq * 100 >=
+ totaltrans * TEMPLATE_SAME_PERCENTAGE )
+ mktemplate( state, statenum, comstate );
+
+ else
+ {
+ mkprot( state, statenum, comstate );
+ mkentry( state, numecs, statenum,
+ JAMSTATE, totaltrans );
+ }
+ }
+
+ else
+ { /* use the proto */
+ mkentry( extrct[extptr], numecs, statenum,
+ prottbl[minprot], mindiff );
+
+ /* If this state was sufficiently different from the
+ * proto we built it from, make it, too, a proto.
+ */
+
+ if ( mindiff * 100 >=
+ totaltrans * NEW_PROTO_DIFF_PERCENTAGE )
+ mkprot( state, statenum, comstate );
+
+ /* Since mkprot added a new proto to the proto queue,
+ * it's possible that "minprot" is no longer on the
+ * proto queue (if it happened to have been the last
+ * entry, it would have been bumped off). If it's
+ * not there, then the new proto took its physical
+ * place (though logically the new proto is at the
+ * beginning of the queue), so in that case the
+ * following call will do nothing.
+ */
+
+ mv2front( minprot );
+ }
+ }
+ }
+
+
+/* cmptmps - compress template table entries
+ *
+ * Template tables are compressed by using the 'template equivalence
+ * classes', which are collections of transition character equivalence
+ * classes which always appear together in templates - really meta-equivalence
+ * classes.
+ */
+
+void cmptmps()
+ {
+ int tmpstorage[CSIZE + 1];
+ register int *tmp = tmpstorage, i, j;
+ int totaltrans, trans;
+
+ peakpairs = numtemps * numecs + tblend;
+
+ if ( usemecs )
+ {
+ /* Create equivalence classes based on data gathered on
+ * template transitions.
+ */
+ nummecs = cre8ecs( tecfwd, tecbck, numecs );
+ }
+
+ else
+ nummecs = numecs;
+
+ while ( lastdfa + numtemps + 1 >= current_max_dfas )
+ increase_max_dfas();
+
+ /* Loop through each template. */
+
+ for ( i = 1; i <= numtemps; ++i )
+ {
+ /* Number of non-jam transitions out of this template. */
+ totaltrans = 0;
+
+ for ( j = 1; j <= numecs; ++j )
+ {
+ trans = tnxt[numecs * i + j];
+
+ if ( usemecs )
+ {
+ /* The absolute value of tecbck is the
+ * meta-equivalence class of a given
+ * equivalence class, as set up by cre8ecs().
+ */
+ if ( tecbck[j] > 0 )
+ {
+ tmp[tecbck[j]] = trans;
+
+ if ( trans > 0 )
+ ++totaltrans;
+ }
+ }
+
+ else
+ {
+ tmp[j] = trans;
+
+ if ( trans > 0 )
+ ++totaltrans;
+ }
+ }
+
+ /* It is assumed (in a rather subtle way) in the skeleton
+ * that if we're using meta-equivalence classes, the def[]
+ * entry for all templates is the jam template, i.e.,
+ * templates never default to other non-jam table entries
+ * (e.g., another template)
+ */
+
+ /* Leave room for the jam-state after the last real state. */
+ mkentry( tmp, nummecs, lastdfa + i + 1, JAMSTATE, totaltrans );
+ }
+ }
+
+
+
+/* expand_nxt_chk - expand the next check arrays */
+
+void expand_nxt_chk()
+ {
+ register int old_max = current_max_xpairs;
+
+ current_max_xpairs += MAX_XPAIRS_INCREMENT;
+
+ ++num_reallocs;
+
+ nxt = reallocate_integer_array( nxt, current_max_xpairs );
+ chk = reallocate_integer_array( chk, current_max_xpairs );
+
+ zero_out( (char *) (chk + old_max),
+ (size_t) (MAX_XPAIRS_INCREMENT * sizeof( int )) );
+ }
+
+
+/* find_table_space - finds a space in the table for a state to be placed
+ *
+ * synopsis
+ * int *state, numtrans, block_start;
+ * int find_table_space();
+ *
+ * block_start = find_table_space( state, numtrans );
+ *
+ * State is the state to be added to the full speed transition table.
+ * Numtrans is the number of out-transitions for the state.
+ *
+ * find_table_space() returns the position of the start of the first block (in
+ * chk) able to accommodate the state
+ *
+ * In determining if a state will or will not fit, find_table_space() must take
+ * into account the fact that an end-of-buffer state will be added at [0],
+ * and an action number will be added in [-1].
+ */
+
+int find_table_space( state, numtrans )
+int *state, numtrans;
+ {
+ /* Firstfree is the position of the first possible occurrence of two
+ * consecutive unused records in the chk and nxt arrays.
+ */
+ register int i;
+ register int *state_ptr, *chk_ptr;
+ register int *ptr_to_last_entry_in_state;
+
+ /* If there are too many out-transitions, put the state at the end of
+ * nxt and chk.
+ */
+ if ( numtrans > MAX_XTIONS_FULL_INTERIOR_FIT )
+ {
+ /* If table is empty, return the first available spot in
+ * chk/nxt, which should be 1.
+ */
+ if ( tblend < 2 )
+ return 1;
+
+ /* Start searching for table space near the end of
+ * chk/nxt arrays.
+ */
+ i = tblend - numecs;
+ }
+
+ else
+ /* Start searching for table space from the beginning
+ * (skipping only the elements which will definitely not
+ * hold the new state).
+ */
+ i = firstfree;
+
+ while ( 1 ) /* loops until a space is found */
+ {
+ while ( i + numecs >= current_max_xpairs )
+ expand_nxt_chk();
+
+ /* Loops until space for end-of-buffer and action number
+ * are found.
+ */
+ while ( 1 )
+ {
+ /* Check for action number space. */
+ if ( chk[i - 1] == 0 )
+ {
+ /* Check for end-of-buffer space. */
+ if ( chk[i] == 0 )
+ break;
+
+ else
+ /* Since i != 0, there is no use
+ * checking to see if (++i) - 1 == 0,
+ * because that's the same as i == 0,
+ * so we skip a space.
+ */
+ i += 2;
+ }
+
+ else
+ ++i;
+
+ while ( i + numecs >= current_max_xpairs )
+ expand_nxt_chk();
+ }
+
+ /* If we started search from the beginning, store the new
+ * firstfree for the next call of find_table_space().
+ */
+ if ( numtrans <= MAX_XTIONS_FULL_INTERIOR_FIT )
+ firstfree = i + 1;
+
+ /* Check to see if all elements in chk (and therefore nxt)
+ * that are needed for the new state have not yet been taken.
+ */
+
+ state_ptr = &state[1];
+ ptr_to_last_entry_in_state = &chk[i + numecs + 1];
+
+ for ( chk_ptr = &chk[i + 1];
+ chk_ptr != ptr_to_last_entry_in_state; ++chk_ptr )
+ if ( *(state_ptr++) != 0 && *chk_ptr != 0 )
+ break;
+
+ if ( chk_ptr == ptr_to_last_entry_in_state )
+ return i;
+
+ else
+ ++i;
+ }
+ }
+
+
+/* inittbl - initialize transition tables
+ *
+ * Initializes "firstfree" to be one beyond the end of the table. Initializes
+ * all "chk" entries to be zero.
+ */
+void inittbl()
+ {
+ register int i;
+
+ zero_out( (char *) chk, (size_t) (current_max_xpairs * sizeof( int )) );
+
+ tblend = 0;
+ firstfree = tblend + 1;
+ numtemps = 0;
+
+ if ( usemecs )
+ {
+ /* Set up doubly-linked meta-equivalence classes; these
+ * are sets of equivalence classes which all have identical
+ * transitions out of TEMPLATES.
+ */
+
+ tecbck[1] = NIL;
+
+ for ( i = 2; i <= numecs; ++i )
+ {
+ tecbck[i] = i - 1;
+ tecfwd[i - 1] = i;
+ }
+
+ tecfwd[numecs] = NIL;
+ }
+ }
+
+
+/* mkdeftbl - make the default, "jam" table entries */
+
+void mkdeftbl()
+ {
+ int i;
+
+ jamstate = lastdfa + 1;
+
+ ++tblend; /* room for transition on end-of-buffer character */
+
+ while ( tblend + numecs >= current_max_xpairs )
+ expand_nxt_chk();
+
+ /* Add in default end-of-buffer transition. */
+ nxt[tblend] = end_of_buffer_state;
+ chk[tblend] = jamstate;
+
+ for ( i = 1; i <= numecs; ++i )
+ {
+ nxt[tblend + i] = 0;
+ chk[tblend + i] = jamstate;
+ }
+
+ jambase = tblend;
+
+ base[jamstate] = jambase;
+ def[jamstate] = 0;
+
+ tblend += numecs;
+ ++numtemps;
+ }
+
+
+/* mkentry - create base/def and nxt/chk entries for transition array
+ *
+ * synopsis
+ * int state[numchars + 1], numchars, statenum, deflink, totaltrans;
+ * mkentry( state, numchars, statenum, deflink, totaltrans );
+ *
+ * "state" is a transition array "numchars" characters in size, "statenum"
+ * is the offset to be used into the base/def tables, and "deflink" is the
+ * entry to put in the "def" table entry. If "deflink" is equal to
+ * "JAMSTATE", then no attempt will be made to fit zero entries of "state"
+ * (i.e., jam entries) into the table. It is assumed that by linking to
+ * "JAMSTATE" they will be taken care of. In any case, entries in "state"
+ * marking transitions to "SAME_TRANS" are treated as though they will be
+ * taken care of by whereever "deflink" points. "totaltrans" is the total
+ * number of transitions out of the state. If it is below a certain threshold,
+ * the tables are searched for an interior spot that will accommodate the
+ * state array.
+ */
+
+void mkentry( state, numchars, statenum, deflink, totaltrans )
+register int *state;
+int numchars, statenum, deflink, totaltrans;
+ {
+ register int minec, maxec, i, baseaddr;
+ int tblbase, tbllast;
+
+ if ( totaltrans == 0 )
+ { /* there are no out-transitions */
+ if ( deflink == JAMSTATE )
+ base[statenum] = JAMSTATE;
+ else
+ base[statenum] = 0;
+
+ def[statenum] = deflink;
+ return;
+ }
+
+ for ( minec = 1; minec <= numchars; ++minec )
+ {
+ if ( state[minec] != SAME_TRANS )
+ if ( state[minec] != 0 || deflink != JAMSTATE )
+ break;
+ }
+
+ if ( totaltrans == 1 )
+ {
+ /* There's only one out-transition. Save it for later to fill
+ * in holes in the tables.
+ */
+ stack1( statenum, minec, state[minec], deflink );
+ return;
+ }
+
+ for ( maxec = numchars; maxec > 0; --maxec )
+ {
+ if ( state[maxec] != SAME_TRANS )
+ if ( state[maxec] != 0 || deflink != JAMSTATE )
+ break;
+ }
+
+ /* Whether we try to fit the state table in the middle of the table
+ * entries we have already generated, or if we just take the state
+ * table at the end of the nxt/chk tables, we must make sure that we
+ * have a valid base address (i.e., non-negative). Note that
+ * negative base addresses dangerous at run-time (because indexing
+ * the nxt array with one and a low-valued character will access
+ * memory before the start of the array.
+ */
+
+ /* Find the first transition of state that we need to worry about. */
+ if ( totaltrans * 100 <= numchars * INTERIOR_FIT_PERCENTAGE )
+ {
+ /* Attempt to squeeze it into the middle of the tables. */
+ baseaddr = firstfree;
+
+ while ( baseaddr < minec )
+ {
+ /* Using baseaddr would result in a negative base
+ * address below; find the next free slot.
+ */
+ for ( ++baseaddr; chk[baseaddr] != 0; ++baseaddr )
+ ;
+ }
+
+ while ( baseaddr + maxec - minec + 1 >= current_max_xpairs )
+ expand_nxt_chk();
+
+ for ( i = minec; i <= maxec; ++i )
+ if ( state[i] != SAME_TRANS &&
+ (state[i] != 0 || deflink != JAMSTATE) &&
+ chk[baseaddr + i - minec] != 0 )
+ { /* baseaddr unsuitable - find another */
+ for ( ++baseaddr;
+ baseaddr < current_max_xpairs &&
+ chk[baseaddr] != 0; ++baseaddr )
+ ;
+
+ while ( baseaddr + maxec - minec + 1 >=
+ current_max_xpairs )
+ expand_nxt_chk();
+
+ /* Reset the loop counter so we'll start all
+ * over again next time it's incremented.
+ */
+
+ i = minec - 1;
+ }
+ }
+
+ else
+ {
+ /* Ensure that the base address we eventually generate is
+ * non-negative.
+ */
+ baseaddr = MAX( tblend + 1, minec );
+ }
+
+ tblbase = baseaddr - minec;
+ tbllast = tblbase + maxec;
+
+ while ( tbllast + 1 >= current_max_xpairs )
+ expand_nxt_chk();
+
+ base[statenum] = tblbase;
+ def[statenum] = deflink;
+
+ for ( i = minec; i <= maxec; ++i )
+ if ( state[i] != SAME_TRANS )
+ if ( state[i] != 0 || deflink != JAMSTATE )
+ {
+ nxt[tblbase + i] = state[i];
+ chk[tblbase + i] = statenum;
+ }
+
+ if ( baseaddr == firstfree )
+ /* Find next free slot in tables. */
+ for ( ++firstfree; chk[firstfree] != 0; ++firstfree )
+ ;
+
+ tblend = MAX( tblend, tbllast );
+ }
+
+
+/* mk1tbl - create table entries for a state (or state fragment) which
+ * has only one out-transition
+ */
+
+void mk1tbl( state, sym, onenxt, onedef )
+int state, sym, onenxt, onedef;
+ {
+ if ( firstfree < sym )
+ firstfree = sym;
+
+ while ( chk[firstfree] != 0 )
+ if ( ++firstfree >= current_max_xpairs )
+ expand_nxt_chk();
+
+ base[state] = firstfree - sym;
+ def[state] = onedef;
+ chk[firstfree] = state;
+ nxt[firstfree] = onenxt;
+
+ if ( firstfree > tblend )
+ {
+ tblend = firstfree++;
+
+ if ( firstfree >= current_max_xpairs )
+ expand_nxt_chk();
+ }
+ }
+
+
+/* mkprot - create new proto entry */
+
+void mkprot( state, statenum, comstate )
+int state[], statenum, comstate;
+ {
+ int i, slot, tblbase;
+
+ if ( ++numprots >= MSP || numecs * numprots >= PROT_SAVE_SIZE )
+ {
+ /* Gotta make room for the new proto by dropping last entry in
+ * the queue.
+ */
+ slot = lastprot;
+ lastprot = protprev[lastprot];
+ protnext[lastprot] = NIL;
+ }
+
+ else
+ slot = numprots;
+
+ protnext[slot] = firstprot;
+
+ if ( firstprot != NIL )
+ protprev[firstprot] = slot;
+
+ firstprot = slot;
+ prottbl[slot] = statenum;
+ protcomst[slot] = comstate;
+
+ /* Copy state into save area so it can be compared with rapidly. */
+ tblbase = numecs * (slot - 1);
+
+ for ( i = 1; i <= numecs; ++i )
+ protsave[tblbase + i] = state[i];
+ }
+
+
+/* mktemplate - create a template entry based on a state, and connect the state
+ * to it
+ */
+
+void mktemplate( state, statenum, comstate )
+int state[], statenum, comstate;
+ {
+ int i, numdiff, tmpbase, tmp[CSIZE + 1];
+ Char transset[CSIZE + 1];
+ int tsptr;
+
+ ++numtemps;
+
+ tsptr = 0;
+
+ /* Calculate where we will temporarily store the transition table
+ * of the template in the tnxt[] array. The final transition table
+ * gets created by cmptmps().
+ */
+
+ tmpbase = numtemps * numecs;
+
+ if ( tmpbase + numecs >= current_max_template_xpairs )
+ {
+ current_max_template_xpairs += MAX_TEMPLATE_XPAIRS_INCREMENT;
+
+ ++num_reallocs;
+
+ tnxt = reallocate_integer_array( tnxt,
+ current_max_template_xpairs );
+ }
+
+ for ( i = 1; i <= numecs; ++i )
+ if ( state[i] == 0 )
+ tnxt[tmpbase + i] = 0;
+ else
+ {
+ transset[tsptr++] = i;
+ tnxt[tmpbase + i] = comstate;
+ }
+
+ if ( usemecs )
+ mkeccl( transset, tsptr, tecfwd, tecbck, numecs, 0 );
+
+ mkprot( tnxt + tmpbase, -numtemps, comstate );
+
+ /* We rely on the fact that mkprot adds things to the beginning
+ * of the proto queue.
+ */
+
+ numdiff = tbldiff( state, firstprot, tmp );
+ mkentry( tmp, numecs, statenum, -numtemps, numdiff );
+ }
+
+
+/* mv2front - move proto queue element to front of queue */
+
+void mv2front( qelm )
+int qelm;
+ {
+ if ( firstprot != qelm )
+ {
+ if ( qelm == lastprot )
+ lastprot = protprev[lastprot];
+
+ protnext[protprev[qelm]] = protnext[qelm];
+
+ if ( protnext[qelm] != NIL )
+ protprev[protnext[qelm]] = protprev[qelm];
+
+ protprev[qelm] = NIL;
+ protnext[qelm] = firstprot;
+ protprev[firstprot] = qelm;
+ firstprot = qelm;
+ }
+ }
+
+
+/* place_state - place a state into full speed transition table
+ *
+ * State is the statenum'th state. It is indexed by equivalence class and
+ * gives the number of the state to enter for a given equivalence class.
+ * Transnum is the number of out-transitions for the state.
+ */
+
+void place_state( state, statenum, transnum )
+int *state, statenum, transnum;
+ {
+ register int i;
+ register int *state_ptr;
+ int position = find_table_space( state, transnum );
+
+ /* "base" is the table of start positions. */
+ base[statenum] = position;
+
+ /* Put in action number marker; this non-zero number makes sure that
+ * find_table_space() knows that this position in chk/nxt is taken
+ * and should not be used for another accepting number in another
+ * state.
+ */
+ chk[position - 1] = 1;
+
+ /* Put in end-of-buffer marker; this is for the same purposes as
+ * above.
+ */
+ chk[position] = 1;
+
+ /* Place the state into chk and nxt. */
+ state_ptr = &state[1];
+
+ for ( i = 1; i <= numecs; ++i, ++state_ptr )
+ if ( *state_ptr != 0 )
+ {
+ chk[position + i] = i;
+ nxt[position + i] = *state_ptr;
+ }
+
+ if ( position + numecs > tblend )
+ tblend = position + numecs;
+ }
+
+
+/* stack1 - save states with only one out-transition to be processed later
+ *
+ * If there's room for another state on the "one-transition" stack, the
+ * state is pushed onto it, to be processed later by mk1tbl. If there's
+ * no room, we process the sucker right now.
+ */
+
+void stack1( statenum, sym, nextstate, deflink )
+int statenum, sym, nextstate, deflink;
+ {
+ if ( onesp >= ONE_STACK_SIZE - 1 )
+ mk1tbl( statenum, sym, nextstate, deflink );
+
+ else
+ {
+ ++onesp;
+ onestate[onesp] = statenum;
+ onesym[onesp] = sym;
+ onenext[onesp] = nextstate;
+ onedef[onesp] = deflink;
+ }
+ }
+
+
+/* tbldiff - compute differences between two state tables
+ *
+ * "state" is the state array which is to be extracted from the pr'th
+ * proto. "pr" is both the number of the proto we are extracting from
+ * and an index into the save area where we can find the proto's complete
+ * state table. Each entry in "state" which differs from the corresponding
+ * entry of "pr" will appear in "ext".
+ *
+ * Entries which are the same in both "state" and "pr" will be marked
+ * as transitions to "SAME_TRANS" in "ext". The total number of differences
+ * between "state" and "pr" is returned as function value. Note that this
+ * number is "numecs" minus the number of "SAME_TRANS" entries in "ext".
+ */
+
+int tbldiff( state, pr, ext )
+int state[], pr, ext[];
+ {
+ register int i, *sp = state, *ep = ext, *protp;
+ register int numdiff = 0;
+
+ protp = &protsave[numecs * (pr - 1)];
+
+ for ( i = numecs; i > 0; --i )
+ {
+ if ( *++protp == *++sp )
+ *++ep = SAME_TRANS;
+ else
+ {
+ *++ep = *sp;
+ ++numdiff;
+ }
+ }
+
+ return numdiff;
+ }
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-26 23:40:19 +0000