/* $NetBSD: dfa.c,v 1.1.1.1 2009/10/26 00:25:56 christos 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 "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; { register int i, j; for (i = 1; i <= num_states; ++i) { int ns = nfa_states[i]; register int type = state_type[ns]; register 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; { register int i, j; register 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) { register 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; } } bubble (rule_set, num_associated_rules); 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[]; { register 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; { register 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 (); } flex_free ((void *) accset); flex_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; register 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. * We use bubble because there probably * aren't very many states. */ bubble (sns, numstates); 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) bubble (sns, numstates); 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. We use a bubble * sort since the list is probably quite small. */ bubble (accset, nacc); 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; } } } } }