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cosmopolitan/third_party/lex/dfa.c

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/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
│vi: set et ft=c ts=8 sw=8 fenc=utf-8 :vi│
└─────────────────────────────────────────────────────────────────────────────*/
/* clang-format off */
/* $OpenBSD: dfa.c,v 1.8 2015/11/19 23:20:34 tedu Exp $ */
/* dfa - DFA construction 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 the following conditions */
/* are met: */
/* 1. Redistributions of source code must retain the above copyright */
/* notice, this list of conditions and the following disclaimer. */
/* 2. Redistributions in binary form must reproduce the above copyright */
/* notice, this list of conditions and the following disclaimer in the */
/* documentation and/or other materials provided with the distribution. */
/* 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. */
#include "flexdef.h"
#include "libc/alg/alg.h"
#include "libc/mem/mem.h"
#include "tables.h"
/* declare functions that have forward references */
void dump_associated_rules PROTO ((FILE *, int));
void dump_transitions PROTO ((FILE *, int[]));
void sympartition PROTO ((int[], int, int[], int[]));
int symfollowset PROTO ((int[], int, int, int[]));
/* check_for_backing_up - check a DFA state for backing up
*
* synopsis
* void check_for_backing_up( int ds, int state[numecs] );
*
* ds is the number of the state to check and state[] is its out-transitions,
* indexed by equivalence class.
*/
void check_for_backing_up (ds, state)
int ds;
int state[];
{
if ((reject && !dfaacc[ds].dfaacc_set) || (!reject && !dfaacc[ds].dfaacc_state)) { /* state is non-accepting */
++num_backing_up;
if (backing_up_report) {
fprintf (backing_up_file,
_("State #%d is non-accepting -\n"), ds);
/* identify the state */
dump_associated_rules (backing_up_file, ds);
/* Now identify it further using the out- and
* jam-transitions.
*/
dump_transitions (backing_up_file, state);
putc ('\n', backing_up_file);
}
}
}
/* check_trailing_context - check to see if NFA state set constitutes
* "dangerous" trailing context
*
* synopsis
* void check_trailing_context( int nfa_states[num_states+1], int num_states,
* int accset[nacc+1], int nacc );
*
* NOTES
* Trailing context is "dangerous" if both the head and the trailing
* part are of variable size \and/ there's a DFA state which contains
* both an accepting state for the head part of the rule and NFA states
* which occur after the beginning of the trailing context.
*
* When such a rule is matched, it's impossible to tell if having been
* in the DFA state indicates the beginning of the trailing context or
* further-along scanning of the pattern. In these cases, a warning
* message is issued.
*
* nfa_states[1 .. num_states] is the list of NFA states in the DFA.
* accset[1 .. nacc] is the list of accepting numbers for the DFA state.
*/
void check_trailing_context (nfa_states, num_states, accset, nacc)
int *nfa_states, num_states;
int *accset;
int nacc;
{
int i, j;
for (i = 1; i <= num_states; ++i) {
int ns = nfa_states[i];
int type = state_type[ns];
int ar = assoc_rule[ns];
if (type == STATE_NORMAL || rule_type[ar] != RULE_VARIABLE) { /* do nothing */
}
else if (type == STATE_TRAILING_CONTEXT) {
/* Potential trouble. Scan set of accepting numbers
* for the one marking the end of the "head". We
* assume that this looping will be fairly cheap
* since it's rare that an accepting number set
* is large.
*/
for (j = 1; j <= nacc; ++j)
if (accset[j] & YY_TRAILING_HEAD_MASK) {
line_warning (_
("dangerous trailing context"),
rule_linenum[ar]);
return;
}
}
}
}
/* dump_associated_rules - list the rules associated with a DFA state
*
* Goes through the set of NFA states associated with the DFA and
* extracts the first MAX_ASSOC_RULES unique rules, sorts them,
* and writes a report to the given file.
*/
void dump_associated_rules (file, ds)
FILE *file;
int ds;
{
int i, j;
int num_associated_rules = 0;
int rule_set[MAX_ASSOC_RULES + 1];
int *dset = dss[ds];
int size = dfasiz[ds];
for (i = 1; i <= size; ++i) {
int rule_num = rule_linenum[assoc_rule[dset[i]]];
for (j = 1; j <= num_associated_rules; ++j)
if (rule_num == rule_set[j])
break;
if (j > num_associated_rules) { /* new rule */
if (num_associated_rules < MAX_ASSOC_RULES)
rule_set[++num_associated_rules] =
rule_num;
}
}
qsort (&rule_set [1], num_associated_rules, sizeof (rule_set [1]), intcmp);
fprintf (file, _(" associated rule line numbers:"));
for (i = 1; i <= num_associated_rules; ++i) {
if (i % 8 == 1)
putc ('\n', file);
fprintf (file, "\t%d", rule_set[i]);
}
putc ('\n', file);
}
/* dump_transitions - list the transitions associated with a DFA state
*
* synopsis
* dump_transitions( FILE *file, int state[numecs] );
*
* Goes through the set of out-transitions and lists them in human-readable
* form (i.e., not as equivalence classes); also lists jam transitions
* (i.e., all those which are not out-transitions, plus EOF). The dump
* is done to the given file.
*/
void dump_transitions (file, state)
FILE *file;
int state[];
{
int i, ec;
int out_char_set[CSIZE];
for (i = 0; i < csize; ++i) {
ec = ABS (ecgroup[i]);
out_char_set[i] = state[ec];
}
fprintf (file, _(" out-transitions: "));
list_character_set (file, out_char_set);
/* now invert the members of the set to get the jam transitions */
for (i = 0; i < csize; ++i)
out_char_set[i] = !out_char_set[i];
fprintf (file, _("\n jam-transitions: EOF "));
list_character_set (file, out_char_set);
putc ('\n', file);
}
/* epsclosure - construct the epsilon closure of a set of ndfa states
*
* synopsis
* int *epsclosure( int t[num_states], int *numstates_addr,
* int accset[num_rules+1], int *nacc_addr,
* int *hashval_addr );
*
* NOTES
* The epsilon closure is the set of all states reachable by an arbitrary
* number of epsilon transitions, which themselves do not have epsilon
* transitions going out, unioned with the set of states which have non-null
* accepting numbers. t is an array of size numstates of nfa state numbers.
* Upon return, t holds the epsilon closure and *numstates_addr is updated.
* accset holds a list of the accepting numbers, and the size of accset is
* given by *nacc_addr. t may be subjected to reallocation if it is not
* large enough to hold the epsilon closure.
*
* hashval is the hash value for the dfa corresponding to the state set.
*/
int *epsclosure (t, ns_addr, accset, nacc_addr, hv_addr)
int *t, *ns_addr, accset[], *nacc_addr, *hv_addr;
{
int stkpos, ns, tsp;
int numstates = *ns_addr, nacc, hashval, transsym, nfaccnum;
int stkend, nstate;
static int did_stk_init = false, *stk;
#define MARK_STATE(state) \
do{ trans1[state] = trans1[state] - MARKER_DIFFERENCE;} while(0)
#define IS_MARKED(state) (trans1[state] < 0)
#define UNMARK_STATE(state) \
do{ trans1[state] = trans1[state] + MARKER_DIFFERENCE;} while(0)
#define CHECK_ACCEPT(state) \
do{ \
nfaccnum = accptnum[state]; \
if ( nfaccnum != NIL ) \
accset[++nacc] = nfaccnum; \
}while(0)
#define DO_REALLOCATION() \
do { \
current_max_dfa_size += MAX_DFA_SIZE_INCREMENT; \
++num_reallocs; \
t = reallocate_integer_array( t, current_max_dfa_size ); \
stk = reallocate_integer_array( stk, current_max_dfa_size ); \
}while(0) \
#define PUT_ON_STACK(state) \
do { \
if ( ++stkend >= current_max_dfa_size ) \
DO_REALLOCATION(); \
stk[stkend] = state; \
MARK_STATE(state); \
}while(0)
#define ADD_STATE(state) \
do { \
if ( ++numstates >= current_max_dfa_size ) \
DO_REALLOCATION(); \
t[numstates] = state; \
hashval += state; \
}while(0)
#define STACK_STATE(state) \
do { \
PUT_ON_STACK(state); \
CHECK_ACCEPT(state); \
if ( nfaccnum != NIL || transchar[state] != SYM_EPSILON ) \
ADD_STATE(state); \
}while(0)
if (!did_stk_init) {
stk = allocate_integer_array (current_max_dfa_size);
did_stk_init = true;
}
nacc = stkend = hashval = 0;
for (nstate = 1; nstate <= numstates; ++nstate) {
ns = t[nstate];
/* The state could be marked if we've already pushed it onto
* the stack.
*/
if (!IS_MARKED (ns)) {
PUT_ON_STACK (ns);
CHECK_ACCEPT (ns);
hashval += ns;
}
}
for (stkpos = 1; stkpos <= stkend; ++stkpos) {
ns = stk[stkpos];
transsym = transchar[ns];
if (transsym == SYM_EPSILON) {
tsp = trans1[ns] + MARKER_DIFFERENCE;
if (tsp != NO_TRANSITION) {
if (!IS_MARKED (tsp))
STACK_STATE (tsp);
tsp = trans2[ns];
if (tsp != NO_TRANSITION
&& !IS_MARKED (tsp))
STACK_STATE (tsp);
}
}
}
/* Clear out "visit" markers. */
for (stkpos = 1; stkpos <= stkend; ++stkpos) {
if (IS_MARKED (stk[stkpos]))
UNMARK_STATE (stk[stkpos]);
else
flexfatal (_
("consistency check failed in epsclosure()"));
}
*ns_addr = numstates;
*hv_addr = hashval;
*nacc_addr = nacc;
return t;
}
/* increase_max_dfas - increase the maximum number of DFAs */
void increase_max_dfas ()
{
current_max_dfas += MAX_DFAS_INCREMENT;
++num_reallocs;
base = reallocate_integer_array (base, current_max_dfas);
def = reallocate_integer_array (def, current_max_dfas);
dfasiz = reallocate_integer_array (dfasiz, current_max_dfas);
accsiz = reallocate_integer_array (accsiz, current_max_dfas);
dhash = reallocate_integer_array (dhash, current_max_dfas);
dss = reallocate_int_ptr_array (dss, current_max_dfas);
dfaacc = reallocate_dfaacc_union (dfaacc, current_max_dfas);
if (nultrans)
nultrans =
reallocate_integer_array (nultrans,
current_max_dfas);
}
/* ntod - convert an ndfa to a dfa
*
* Creates the dfa corresponding to the ndfa we've constructed. The
* dfa starts out in state #1.
*/
void ntod ()
{
int *accset, ds, nacc, newds;
int sym, hashval, numstates, dsize;
int num_full_table_rows=0; /* used only for -f */
int *nset, *dset;
int targptr, totaltrans, i, comstate, comfreq, targ;
int symlist[CSIZE + 1];
int num_start_states;
int todo_head, todo_next;
struct yytbl_data *yynxt_tbl = 0;
flex_int32_t *yynxt_data = 0, yynxt_curr = 0;
/* Note that the following are indexed by *equivalence classes*
* and not by characters. Since equivalence classes are indexed
* beginning with 1, even if the scanner accepts NUL's, this
* means that (since every character is potentially in its own
* equivalence class) these arrays must have room for indices
* from 1 to CSIZE, so their size must be CSIZE + 1.
*/
int duplist[CSIZE + 1], state[CSIZE + 1];
int targfreq[CSIZE + 1], targstate[CSIZE + 1];
/* accset needs to be large enough to hold all of the rules present
* in the input, *plus* their YY_TRAILING_HEAD_MASK variants.
*/
accset = allocate_integer_array ((num_rules + 1) * 2);
nset = allocate_integer_array (current_max_dfa_size);
/* The "todo" queue is represented by the head, which is the DFA
* state currently being processed, and the "next", which is the
* next DFA state number available (not in use). We depend on the
* fact that snstods() returns DFA's \in increasing order/, and thus
* need only know the bounds of the dfas to be processed.
*/
todo_head = todo_next = 0;
for (i = 0; i <= csize; ++i) {
duplist[i] = NIL;
symlist[i] = false;
}
for (i = 0; i <= num_rules; ++i)
accset[i] = NIL;
if (trace) {
dumpnfa (scset[1]);
fputs (_("\n\nDFA Dump:\n\n"), stderr);
}
inittbl ();
/* Check to see whether we should build a separate table for
* transitions on NUL characters. We don't do this for full-speed
* (-F) scanners, since for them we don't have a simple state
* number lying around with which to index the table. We also
* don't bother doing it for scanners unless (1) NUL is in its own
* equivalence class (indicated by a positive value of
* ecgroup[NUL]), (2) NUL's equivalence class is the last
* equivalence class, and (3) the number of equivalence classes is
* the same as the number of characters. This latter case comes
* about when useecs is false or when it's true but every character
* still manages to land in its own class (unlikely, but it's
* cheap to check for). If all these things are true then the
* character code needed to represent NUL's equivalence class for
* indexing the tables is going to take one more bit than the
* number of characters, and therefore we won't be assured of
* being able to fit it into a YY_CHAR variable. This rules out
* storing the transitions in a compressed table, since the code
* for interpreting them uses a YY_CHAR variable (perhaps it
* should just use an integer, though; this is worth pondering ...
* ###).
*
* Finally, for full tables, we want the number of entries in the
* table to be a power of two so the array references go fast (it
* will just take a shift to compute the major index). If
* encoding NUL's transitions in the table will spoil this, we
* give it its own table (note that this will be the case if we're
* not using equivalence classes).
*/
/* Note that the test for ecgroup[0] == numecs below accomplishes
* both (1) and (2) above
*/
if (!fullspd && ecgroup[0] == numecs) {
/* NUL is alone in its equivalence class, which is the
* last one.
*/
int use_NUL_table = (numecs == csize);
if (fulltbl && !use_NUL_table) {
/* We still may want to use the table if numecs
* is a power of 2.
*/
int power_of_two;
for (power_of_two = 1; power_of_two <= csize;
power_of_two *= 2)
if (numecs == power_of_two) {
use_NUL_table = true;
break;
}
}
if (use_NUL_table)
nultrans =
allocate_integer_array (current_max_dfas);
/* From now on, nultrans != nil indicates that we're
* saving null transitions for later, separate encoding.
*/
}
if (fullspd) {
for (i = 0; i <= numecs; ++i)
state[i] = 0;
place_state (state, 0, 0);
dfaacc[0].dfaacc_state = 0;
}
else if (fulltbl) {
if (nultrans)
/* We won't be including NUL's transitions in the
* table, so build it for entries from 0 .. numecs - 1.
*/
num_full_table_rows = numecs;
else
/* Take into account the fact that we'll be including
* the NUL entries in the transition table. Build it
* from 0 .. numecs.
*/
num_full_table_rows = numecs + 1;
/* Begin generating yy_nxt[][]
* This spans the entire LONG function.
* This table is tricky because we don't know how big it will be.
* So we'll have to realloc() on the way...
* we'll wait until we can calculate yynxt_tbl->td_hilen.
*/
yynxt_tbl =
(struct yytbl_data *) calloc (1,
sizeof (struct
yytbl_data));
yytbl_data_init (yynxt_tbl, YYTD_ID_NXT);
yynxt_tbl->td_hilen = 1;
yynxt_tbl->td_lolen = num_full_table_rows;
yynxt_tbl->td_data = yynxt_data =
(flex_int32_t *) calloc (yynxt_tbl->td_lolen *
yynxt_tbl->td_hilen,
sizeof (flex_int32_t));
yynxt_curr = 0;
buf_prints (&yydmap_buf,
"\t{YYTD_ID_NXT, (void**)&yy_nxt, sizeof(%s)},\n",
long_align ? "flex_int32_t" : "flex_int16_t");
/* Unless -Ca, declare it "short" because it's a real
* long-shot that that won't be large enough.
*/
if (gentables)
out_str_dec
("static yyconst %s yy_nxt[][%d] =\n {\n",
long_align ? "flex_int32_t" : "flex_int16_t",
num_full_table_rows);
else {
out_dec ("#undef YY_NXT_LOLEN\n#define YY_NXT_LOLEN (%d)\n", num_full_table_rows);
out_str ("static yyconst %s *yy_nxt =0;\n",
long_align ? "flex_int32_t" : "flex_int16_t");
}
if (gentables)
outn (" {");
/* Generate 0 entries for state #0. */
for (i = 0; i < num_full_table_rows; ++i) {
mk2data (0);
yynxt_data[yynxt_curr++] = 0;
}
dataflush ();
if (gentables)
outn (" },\n");
}
/* Create the first states. */
num_start_states = lastsc * 2;
for (i = 1; i <= num_start_states; ++i) {
numstates = 1;
/* For each start condition, make one state for the case when
* we're at the beginning of the line (the '^' operator) and
* one for the case when we're not.
*/
if (i % 2 == 1)
nset[numstates] = scset[(i / 2) + 1];
else
nset[numstates] =
mkbranch (scbol[i / 2], scset[i / 2]);
nset = epsclosure (nset, &numstates, accset, &nacc,
&hashval);
if (snstods (nset, numstates, accset, nacc, hashval, &ds)) {
numas += nacc;
totnst += numstates;
++todo_next;
if (variable_trailing_context_rules && nacc > 0)
check_trailing_context (nset, numstates,
accset, nacc);
}
}
if (!fullspd) {
if (!snstods (nset, 0, accset, 0, 0, &end_of_buffer_state))
flexfatal (_
("could not create unique end-of-buffer state"));
++numas;
++num_start_states;
++todo_next;
}
while (todo_head < todo_next) {
targptr = 0;
totaltrans = 0;
for (i = 1; i <= numecs; ++i)
state[i] = 0;
ds = ++todo_head;
dset = dss[ds];
dsize = dfasiz[ds];
if (trace)
fprintf (stderr, _("state # %d:\n"), ds);
sympartition (dset, dsize, symlist, duplist);
for (sym = 1; sym <= numecs; ++sym) {
if (symlist[sym]) {
symlist[sym] = 0;
if (duplist[sym] == NIL) {
/* Symbol has unique out-transitions. */
numstates =
symfollowset (dset, dsize,
sym, nset);
nset = epsclosure (nset,
&numstates,
accset, &nacc,
&hashval);
if (snstods
(nset, numstates, accset, nacc,
hashval, &newds)) {
totnst = totnst +
numstates;
++todo_next;
numas += nacc;
if (variable_trailing_context_rules && nacc > 0)
check_trailing_context
(nset,
numstates,
accset,
nacc);
}
state[sym] = newds;
if (trace)
fprintf (stderr,
"\t%d\t%d\n", sym,
newds);
targfreq[++targptr] = 1;
targstate[targptr] = newds;
++numuniq;
}
else {
/* sym's equivalence class has the same
* transitions as duplist(sym)'s
* equivalence class.
*/
targ = state[duplist[sym]];
state[sym] = targ;
if (trace)
fprintf (stderr,
"\t%d\t%d\n", sym,
targ);
/* Update frequency count for
* destination state.
*/
i = 0;
while (targstate[++i] != targ) ;
++targfreq[i];
++numdup;
}
++totaltrans;
duplist[sym] = NIL;
}
}
numsnpairs += totaltrans;
if (ds > num_start_states)
check_for_backing_up (ds, state);
if (nultrans) {
nultrans[ds] = state[NUL_ec];
state[NUL_ec] = 0; /* remove transition */
}
if (fulltbl) {
/* Each time we hit here, it's another td_hilen, so we realloc. */
yynxt_tbl->td_hilen++;
yynxt_tbl->td_data = yynxt_data =
(flex_int32_t *) realloc (yynxt_data,
yynxt_tbl->td_hilen *
yynxt_tbl->td_lolen *
sizeof (flex_int32_t));
if (gentables)
outn (" {");
/* Supply array's 0-element. */
if (ds == end_of_buffer_state) {
mk2data (-end_of_buffer_state);
yynxt_data[yynxt_curr++] =
-end_of_buffer_state;
}
else {
mk2data (end_of_buffer_state);
yynxt_data[yynxt_curr++] =
end_of_buffer_state;
}
for (i = 1; i < num_full_table_rows; ++i) {
/* Jams are marked by negative of state
* number.
*/
mk2data (state[i] ? state[i] : -ds);
yynxt_data[yynxt_curr++] =
state[i] ? state[i] : -ds;
}
dataflush ();
if (gentables)
outn (" },\n");
}
else if (fullspd)
place_state (state, ds, totaltrans);
else if (ds == end_of_buffer_state)
/* Special case this state to make sure it does what
* it's supposed to, i.e., jam on end-of-buffer.
*/
stack1 (ds, 0, 0, JAMSTATE);
else { /* normal, compressed state */
/* Determine which destination state is the most
* common, and how many transitions to it there are.
*/
comfreq = 0;
comstate = 0;
for (i = 1; i <= targptr; ++i)
if (targfreq[i] > comfreq) {
comfreq = targfreq[i];
comstate = targstate[i];
}
bldtbl (state, ds, totaltrans, comstate, comfreq);
}
}
if (fulltbl) {
dataend ();
if (tablesext) {
yytbl_data_compress (yynxt_tbl);
if (yytbl_data_fwrite (&tableswr, yynxt_tbl) < 0)
flexerror (_
("Could not write yynxt_tbl[][]"));
}
if (yynxt_tbl) {
yytbl_data_destroy (yynxt_tbl);
yynxt_tbl = 0;
}
}
else if (!fullspd) {
cmptmps (); /* create compressed template entries */
/* Create tables for all the states with only one
* out-transition.
*/
while (onesp > 0) {
mk1tbl (onestate[onesp], onesym[onesp],
onenext[onesp], onedef[onesp]);
--onesp;
}
mkdeftbl ();
}
free ((void *) accset);
free ((void *) nset);
}
/* snstods - converts a set of ndfa states into a dfa state
*
* synopsis
* is_new_state = snstods( int sns[numstates], int numstates,
* int accset[num_rules+1], int nacc,
* int hashval, int *newds_addr );
*
* On return, the dfa state number is in newds.
*/
int snstods (sns, numstates, accset, nacc, hashval, newds_addr)
int sns[], numstates, accset[], nacc, hashval, *newds_addr;
{
int didsort = 0;
int i, j;
int newds, *oldsns;
for (i = 1; i <= lastdfa; ++i)
if (hashval == dhash[i]) {
if (numstates == dfasiz[i]) {
oldsns = dss[i];
if (!didsort) {
/* We sort the states in sns so we
* can compare it to oldsns quickly.
*/
qsort (&sns [1], numstates, sizeof (sns [1]), intcmp);
didsort = 1;
}
for (j = 1; j <= numstates; ++j)
if (sns[j] != oldsns[j])
break;
if (j > numstates) {
++dfaeql;
*newds_addr = i;
return 0;
}
++hshcol;
}
else
++hshsave;
}
/* Make a new dfa. */
if (++lastdfa >= current_max_dfas)
increase_max_dfas ();
newds = lastdfa;
dss[newds] = allocate_integer_array (numstates + 1);
/* If we haven't already sorted the states in sns, we do so now,
* so that future comparisons with it can be made quickly.
*/
if (!didsort)
qsort (&sns [1], numstates, sizeof (sns [1]), intcmp);
for (i = 1; i <= numstates; ++i)
dss[newds][i] = sns[i];
dfasiz[newds] = numstates;
dhash[newds] = hashval;
if (nacc == 0) {
if (reject)
dfaacc[newds].dfaacc_set = (int *) 0;
else
dfaacc[newds].dfaacc_state = 0;
accsiz[newds] = 0;
}
else if (reject) {
/* We sort the accepting set in increasing order so the
* disambiguating rule that the first rule listed is considered
* match in the event of ties will work.
*/
qsort (&accset [1], nacc, sizeof (accset [1]), intcmp);
dfaacc[newds].dfaacc_set =
allocate_integer_array (nacc + 1);
/* Save the accepting set for later */
for (i = 1; i <= nacc; ++i) {
dfaacc[newds].dfaacc_set[i] = accset[i];
if (accset[i] <= num_rules)
/* Who knows, perhaps a REJECT can yield
* this rule.
*/
rule_useful[accset[i]] = true;
}
accsiz[newds] = nacc;
}
else {
/* Find lowest numbered rule so the disambiguating rule
* will work.
*/
j = num_rules + 1;
for (i = 1; i <= nacc; ++i)
if (accset[i] < j)
j = accset[i];
dfaacc[newds].dfaacc_state = j;
if (j <= num_rules)
rule_useful[j] = true;
}
*newds_addr = newds;
return 1;
}
/* symfollowset - follow the symbol transitions one step
*
* synopsis
* numstates = symfollowset( int ds[current_max_dfa_size], int dsize,
* int transsym, int nset[current_max_dfa_size] );
*/
int symfollowset (ds, dsize, transsym, nset)
int ds[], dsize, transsym, nset[];
{
int ns, tsp, sym, i, j, lenccl, ch, numstates, ccllist;
numstates = 0;
for (i = 1; i <= dsize; ++i) { /* for each nfa state ns in the state set of ds */
ns = ds[i];
sym = transchar[ns];
tsp = trans1[ns];
if (sym < 0) { /* it's a character class */
sym = -sym;
ccllist = cclmap[sym];
lenccl = ccllen[sym];
if (cclng[sym]) {
for (j = 0; j < lenccl; ++j) {
/* Loop through negated character
* class.
*/
ch = ccltbl[ccllist + j];
if (ch == 0)
ch = NUL_ec;
if (ch > transsym)
/* Transsym isn't in negated
* ccl.
*/
break;
else if (ch == transsym)
/* next 2 */
goto bottom;
}
/* Didn't find transsym in ccl. */
nset[++numstates] = tsp;
}
else
for (j = 0; j < lenccl; ++j) {
ch = ccltbl[ccllist + j];
if (ch == 0)
ch = NUL_ec;
if (ch > transsym)
break;
else if (ch == transsym) {
nset[++numstates] = tsp;
break;
}
}
}
else if (sym == SYM_EPSILON) { /* do nothing */
}
else if (ABS (ecgroup[sym]) == transsym)
nset[++numstates] = tsp;
bottom:;
}
return numstates;
}
/* sympartition - partition characters with same out-transitions
*
* synopsis
* sympartition( int ds[current_max_dfa_size], int numstates,
* int symlist[numecs], int duplist[numecs] );
*/
void sympartition (ds, numstates, symlist, duplist)
int ds[], numstates;
int symlist[], duplist[];
{
int tch, i, j, k, ns, dupfwd[CSIZE + 1], lenccl, cclp, ich;
/* Partitioning is done by creating equivalence classes for those
* characters which have out-transitions from the given state. Thus
* we are really creating equivalence classes of equivalence classes.
*/
for (i = 1; i <= numecs; ++i) { /* initialize equivalence class list */
duplist[i] = i - 1;
dupfwd[i] = i + 1;
}
duplist[1] = NIL;
dupfwd[numecs] = NIL;
for (i = 1; i <= numstates; ++i) {
ns = ds[i];
tch = transchar[ns];
if (tch != SYM_EPSILON) {
if (tch < -lastccl || tch >= csize) {
flexfatal (_
("bad transition character detected in sympartition()"));
}
if (tch >= 0) { /* character transition */
int ec = ecgroup[tch];
mkechar (ec, dupfwd, duplist);
symlist[ec] = 1;
}
else { /* character class */
tch = -tch;
lenccl = ccllen[tch];
cclp = cclmap[tch];
mkeccl (ccltbl + cclp, lenccl, dupfwd,
duplist, numecs, NUL_ec);
if (cclng[tch]) {
j = 0;
for (k = 0; k < lenccl; ++k) {
ich = ccltbl[cclp + k];
if (ich == 0)
ich = NUL_ec;
for (++j; j < ich; ++j)
symlist[j] = 1;
}
for (++j; j <= numecs; ++j)
symlist[j] = 1;
}
else
for (k = 0; k < lenccl; ++k) {
ich = ccltbl[cclp + k];
if (ich == 0)
ich = NUL_ec;
symlist[ich] = 1;
}
}
}
}
}
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