| 1 | /* nfa - NFA construction routines */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 1990 The Regents of the University of California. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to Berkeley by |
| 8 | * Vern Paxson. |
| 9 | * |
| 10 | * The United States Government has rights in this work pursuant |
| 11 | * to contract no. DE-AC03-76SF00098 between the United States |
| 12 | * Department of Energy and the University of California. |
| 13 | * |
| 14 | * Redistribution and use in source and binary forms are permitted provided |
| 15 | * that: (1) source distributions retain this entire copyright notice and |
| 16 | * comment, and (2) distributions including binaries display the following |
| 17 | * acknowledgement: ``This product includes software developed by the |
| 18 | * University of California, Berkeley and its contributors'' in the |
| 19 | * documentation or other materials provided with the distribution and in |
| 20 | * all advertising materials mentioning features or use of this software. |
| 21 | * Neither the name of the University nor the names of its contributors may |
| 22 | * be used to endorse or promote products derived from this software without |
| 23 | * specific prior written permission. |
| 24 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED |
| 25 | * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF |
| 26 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 27 | */ |
| 28 | |
| 29 | #ifndef lint |
| 30 | static char rcsid[] = |
| 31 | "@(#) $Header: /usr/fsys/odin/a/vern/flex/RCS/nfa.c,v 2.6 90/06/27 23:48:29 vern Exp $ (LBL)"; |
| 32 | #endif |
| 33 | |
| 34 | #include "flexdef.h" |
| 35 | |
| 36 | |
| 37 | /* declare functions that have forward references */ |
| 38 | |
| 39 | int dupmachine PROTO((int)); |
| 40 | void mkxtion PROTO((int, int)); |
| 41 | |
| 42 | |
| 43 | /* add_accept - add an accepting state to a machine |
| 44 | * |
| 45 | * synopsis |
| 46 | * |
| 47 | * add_accept( mach, accepting_number ); |
| 48 | * |
| 49 | * accepting_number becomes mach's accepting number. |
| 50 | */ |
| 51 | |
| 52 | void add_accept( mach, accepting_number ) |
| 53 | int mach, accepting_number; |
| 54 | |
| 55 | { |
| 56 | /* hang the accepting number off an epsilon state. if it is associated |
| 57 | * with a state that has a non-epsilon out-transition, then the state |
| 58 | * will accept BEFORE it makes that transition, i.e., one character |
| 59 | * too soon |
| 60 | */ |
| 61 | |
| 62 | if ( transchar[finalst[mach]] == SYM_EPSILON ) |
| 63 | accptnum[finalst[mach]] = accepting_number; |
| 64 | |
| 65 | else |
| 66 | { |
| 67 | int astate = mkstate( SYM_EPSILON ); |
| 68 | accptnum[astate] = accepting_number; |
| 69 | mach = link_machines( mach, astate ); |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | |
| 74 | /* copysingl - make a given number of copies of a singleton machine |
| 75 | * |
| 76 | * synopsis |
| 77 | * |
| 78 | * newsng = copysingl( singl, num ); |
| 79 | * |
| 80 | * newsng - a new singleton composed of num copies of singl |
| 81 | * singl - a singleton machine |
| 82 | * num - the number of copies of singl to be present in newsng |
| 83 | */ |
| 84 | |
| 85 | int copysingl( singl, num ) |
| 86 | int singl, num; |
| 87 | |
| 88 | { |
| 89 | int copy, i; |
| 90 | |
| 91 | copy = mkstate( SYM_EPSILON ); |
| 92 | |
| 93 | for ( i = 1; i <= num; ++i ) |
| 94 | copy = link_machines( copy, dupmachine( singl ) ); |
| 95 | |
| 96 | return ( copy ); |
| 97 | } |
| 98 | |
| 99 | |
| 100 | /* dumpnfa - debugging routine to write out an nfa |
| 101 | * |
| 102 | * synopsis |
| 103 | * int state1; |
| 104 | * dumpnfa( state1 ); |
| 105 | */ |
| 106 | |
| 107 | void dumpnfa( state1 ) |
| 108 | int state1; |
| 109 | |
| 110 | { |
| 111 | int sym, tsp1, tsp2, anum, ns; |
| 112 | |
| 113 | fprintf( stderr, "\n\n********** beginning dump of nfa with start state %d\n", |
| 114 | state1 ); |
| 115 | |
| 116 | /* we probably should loop starting at firstst[state1] and going to |
| 117 | * lastst[state1], but they're not maintained properly when we "or" |
| 118 | * all of the rules together. So we use our knowledge that the machine |
| 119 | * starts at state 1 and ends at lastnfa. |
| 120 | */ |
| 121 | |
| 122 | /* for ( ns = firstst[state1]; ns <= lastst[state1]; ++ns ) */ |
| 123 | for ( ns = 1; ns <= lastnfa; ++ns ) |
| 124 | { |
| 125 | fprintf( stderr, "state # %4d\t", ns ); |
| 126 | |
| 127 | sym = transchar[ns]; |
| 128 | tsp1 = trans1[ns]; |
| 129 | tsp2 = trans2[ns]; |
| 130 | anum = accptnum[ns]; |
| 131 | |
| 132 | fprintf( stderr, "%3d: %4d, %4d", sym, tsp1, tsp2 ); |
| 133 | |
| 134 | if ( anum != NIL ) |
| 135 | fprintf( stderr, " [%d]", anum ); |
| 136 | |
| 137 | fprintf( stderr, "\n" ); |
| 138 | } |
| 139 | |
| 140 | fprintf( stderr, "********** end of dump\n" ); |
| 141 | } |
| 142 | |
| 143 | |
| 144 | /* dupmachine - make a duplicate of a given machine |
| 145 | * |
| 146 | * synopsis |
| 147 | * |
| 148 | * copy = dupmachine( mach ); |
| 149 | * |
| 150 | * copy - holds duplicate of mach |
| 151 | * mach - machine to be duplicated |
| 152 | * |
| 153 | * note that the copy of mach is NOT an exact duplicate; rather, all the |
| 154 | * transition states values are adjusted so that the copy is self-contained, |
| 155 | * as the original should have been. |
| 156 | * |
| 157 | * also note that the original MUST be contiguous, with its low and high |
| 158 | * states accessible by the arrays firstst and lastst |
| 159 | */ |
| 160 | |
| 161 | int dupmachine( mach ) |
| 162 | int mach; |
| 163 | |
| 164 | { |
| 165 | int i, init, state_offset; |
| 166 | int state = 0; |
| 167 | int last = lastst[mach]; |
| 168 | |
| 169 | for ( i = firstst[mach]; i <= last; ++i ) |
| 170 | { |
| 171 | state = mkstate( transchar[i] ); |
| 172 | |
| 173 | if ( trans1[i] != NO_TRANSITION ) |
| 174 | { |
| 175 | mkxtion( finalst[state], trans1[i] + state - i ); |
| 176 | |
| 177 | if ( transchar[i] == SYM_EPSILON && trans2[i] != NO_TRANSITION ) |
| 178 | mkxtion( finalst[state], trans2[i] + state - i ); |
| 179 | } |
| 180 | |
| 181 | accptnum[state] = accptnum[i]; |
| 182 | } |
| 183 | |
| 184 | if ( state == 0 ) |
| 185 | flexfatal( "empty machine in dupmachine()" ); |
| 186 | |
| 187 | state_offset = state - i + 1; |
| 188 | |
| 189 | init = mach + state_offset; |
| 190 | firstst[init] = firstst[mach] + state_offset; |
| 191 | finalst[init] = finalst[mach] + state_offset; |
| 192 | lastst[init] = lastst[mach] + state_offset; |
| 193 | |
| 194 | return ( init ); |
| 195 | } |
| 196 | |
| 197 | |
| 198 | /* finish_rule - finish up the processing for a rule |
| 199 | * |
| 200 | * synopsis |
| 201 | * |
| 202 | * finish_rule( mach, variable_trail_rule, headcnt, trailcnt ); |
| 203 | * |
| 204 | * An accepting number is added to the given machine. If variable_trail_rule |
| 205 | * is true then the rule has trailing context and both the head and trail |
| 206 | * are variable size. Otherwise if headcnt or trailcnt is non-zero then |
| 207 | * the machine recognizes a pattern with trailing context and headcnt is |
| 208 | * the number of characters in the matched part of the pattern, or zero |
| 209 | * if the matched part has variable length. trailcnt is the number of |
| 210 | * trailing context characters in the pattern, or zero if the trailing |
| 211 | * context has variable length. |
| 212 | */ |
| 213 | |
| 214 | void finish_rule( mach, variable_trail_rule, headcnt, trailcnt ) |
| 215 | int mach, variable_trail_rule, headcnt, trailcnt; |
| 216 | |
| 217 | { |
| 218 | add_accept( mach, num_rules ); |
| 219 | |
| 220 | /* we did this in new_rule(), but it often gets the wrong |
| 221 | * number because we do it before we start parsing the current rule |
| 222 | */ |
| 223 | rule_linenum[num_rules] = linenum; |
| 224 | |
| 225 | /* if this is a continued action, then the line-number has |
| 226 | * already been updated, giving us the wrong number |
| 227 | */ |
| 228 | if ( continued_action ) |
| 229 | --rule_linenum[num_rules]; |
| 230 | |
| 231 | fprintf( temp_action_file, "case %d:\n", num_rules ); |
| 232 | |
| 233 | if ( variable_trail_rule ) |
| 234 | { |
| 235 | rule_type[num_rules] = RULE_VARIABLE; |
| 236 | |
| 237 | if ( performance_report ) |
| 238 | fprintf( stderr, "Variable trailing context rule at line %d\n", |
| 239 | rule_linenum[num_rules] ); |
| 240 | |
| 241 | variable_trailing_context_rules = true; |
| 242 | } |
| 243 | |
| 244 | else |
| 245 | { |
| 246 | rule_type[num_rules] = RULE_NORMAL; |
| 247 | |
| 248 | if ( headcnt > 0 || trailcnt > 0 ) |
| 249 | { |
| 250 | /* do trailing context magic to not match the trailing characters */ |
| 251 | char *scanner_cp = "yy_c_buf_p = yy_cp"; |
| 252 | char *scanner_bp = "yy_bp"; |
| 253 | |
| 254 | fprintf( temp_action_file, |
| 255 | "*yy_cp = yy_hold_char; /* undo effects of setting up yytext */\n" ); |
| 256 | |
| 257 | if ( headcnt > 0 ) |
| 258 | fprintf( temp_action_file, "%s = %s + %d;\n", |
| 259 | scanner_cp, scanner_bp, headcnt ); |
| 260 | |
| 261 | else |
| 262 | fprintf( temp_action_file, |
| 263 | "%s -= %d;\n", scanner_cp, trailcnt ); |
| 264 | |
| 265 | fprintf( temp_action_file, |
| 266 | "YY_DO_BEFORE_ACTION; /* set up yytext again */\n" ); |
| 267 | } |
| 268 | } |
| 269 | |
| 270 | line_directive_out( temp_action_file ); |
| 271 | } |
| 272 | |
| 273 | |
| 274 | /* link_machines - connect two machines together |
| 275 | * |
| 276 | * synopsis |
| 277 | * |
| 278 | * new = link_machines( first, last ); |
| 279 | * |
| 280 | * new - a machine constructed by connecting first to last |
| 281 | * first - the machine whose successor is to be last |
| 282 | * last - the machine whose predecessor is to be first |
| 283 | * |
| 284 | * note: this routine concatenates the machine first with the machine |
| 285 | * last to produce a machine new which will pattern-match first first |
| 286 | * and then last, and will fail if either of the sub-patterns fails. |
| 287 | * FIRST is set to new by the operation. last is unmolested. |
| 288 | */ |
| 289 | |
| 290 | int link_machines( first, last ) |
| 291 | int first, last; |
| 292 | |
| 293 | { |
| 294 | if ( first == NIL ) |
| 295 | return ( last ); |
| 296 | |
| 297 | else if ( last == NIL ) |
| 298 | return ( first ); |
| 299 | |
| 300 | else |
| 301 | { |
| 302 | mkxtion( finalst[first], last ); |
| 303 | finalst[first] = finalst[last]; |
| 304 | lastst[first] = max( lastst[first], lastst[last] ); |
| 305 | firstst[first] = min( firstst[first], firstst[last] ); |
| 306 | |
| 307 | return ( first ); |
| 308 | } |
| 309 | } |
| 310 | |
| 311 | |
| 312 | /* mark_beginning_as_normal - mark each "beginning" state in a machine |
| 313 | * as being a "normal" (i.e., not trailing context- |
| 314 | * associated) states |
| 315 | * |
| 316 | * synopsis |
| 317 | * |
| 318 | * mark_beginning_as_normal( mach ) |
| 319 | * |
| 320 | * mach - machine to mark |
| 321 | * |
| 322 | * The "beginning" states are the epsilon closure of the first state |
| 323 | */ |
| 324 | |
| 325 | void mark_beginning_as_normal( mach ) |
| 326 | register int mach; |
| 327 | |
| 328 | { |
| 329 | switch ( state_type[mach] ) |
| 330 | { |
| 331 | case STATE_NORMAL: |
| 332 | /* oh, we've already visited here */ |
| 333 | return; |
| 334 | |
| 335 | case STATE_TRAILING_CONTEXT: |
| 336 | state_type[mach] = STATE_NORMAL; |
| 337 | |
| 338 | if ( transchar[mach] == SYM_EPSILON ) |
| 339 | { |
| 340 | if ( trans1[mach] != NO_TRANSITION ) |
| 341 | mark_beginning_as_normal( trans1[mach] ); |
| 342 | |
| 343 | if ( trans2[mach] != NO_TRANSITION ) |
| 344 | mark_beginning_as_normal( trans2[mach] ); |
| 345 | } |
| 346 | break; |
| 347 | |
| 348 | default: |
| 349 | flexerror( "bad state type in mark_beginning_as_normal()" ); |
| 350 | break; |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | |
| 355 | /* mkbranch - make a machine that branches to two machines |
| 356 | * |
| 357 | * synopsis |
| 358 | * |
| 359 | * branch = mkbranch( first, second ); |
| 360 | * |
| 361 | * branch - a machine which matches either first's pattern or second's |
| 362 | * first, second - machines whose patterns are to be or'ed (the | operator) |
| 363 | * |
| 364 | * note that first and second are NEITHER destroyed by the operation. Also, |
| 365 | * the resulting machine CANNOT be used with any other "mk" operation except |
| 366 | * more mkbranch's. Compare with mkor() |
| 367 | */ |
| 368 | |
| 369 | int mkbranch( first, second ) |
| 370 | int first, second; |
| 371 | |
| 372 | { |
| 373 | int eps; |
| 374 | |
| 375 | if ( first == NO_TRANSITION ) |
| 376 | return ( second ); |
| 377 | |
| 378 | else if ( second == NO_TRANSITION ) |
| 379 | return ( first ); |
| 380 | |
| 381 | eps = mkstate( SYM_EPSILON ); |
| 382 | |
| 383 | mkxtion( eps, first ); |
| 384 | mkxtion( eps, second ); |
| 385 | |
| 386 | return ( eps ); |
| 387 | } |
| 388 | |
| 389 | |
| 390 | /* mkclos - convert a machine into a closure |
| 391 | * |
| 392 | * synopsis |
| 393 | * new = mkclos( state ); |
| 394 | * |
| 395 | * new - a new state which matches the closure of "state" |
| 396 | */ |
| 397 | |
| 398 | int mkclos( state ) |
| 399 | int state; |
| 400 | |
| 401 | { |
| 402 | return ( mkopt( mkposcl( state ) ) ); |
| 403 | } |
| 404 | |
| 405 | |
| 406 | /* mkopt - make a machine optional |
| 407 | * |
| 408 | * synopsis |
| 409 | * |
| 410 | * new = mkopt( mach ); |
| 411 | * |
| 412 | * new - a machine which optionally matches whatever mach matched |
| 413 | * mach - the machine to make optional |
| 414 | * |
| 415 | * notes: |
| 416 | * 1. mach must be the last machine created |
| 417 | * 2. mach is destroyed by the call |
| 418 | */ |
| 419 | |
| 420 | int mkopt( mach ) |
| 421 | int mach; |
| 422 | |
| 423 | { |
| 424 | int eps; |
| 425 | |
| 426 | if ( ! SUPER_FREE_EPSILON(finalst[mach]) ) |
| 427 | { |
| 428 | eps = mkstate( SYM_EPSILON ); |
| 429 | mach = link_machines( mach, eps ); |
| 430 | } |
| 431 | |
| 432 | /* can't skimp on the following if FREE_EPSILON(mach) is true because |
| 433 | * some state interior to "mach" might point back to the beginning |
| 434 | * for a closure |
| 435 | */ |
| 436 | eps = mkstate( SYM_EPSILON ); |
| 437 | mach = link_machines( eps, mach ); |
| 438 | |
| 439 | mkxtion( mach, finalst[mach] ); |
| 440 | |
| 441 | return ( mach ); |
| 442 | } |
| 443 | |
| 444 | |
| 445 | /* mkor - make a machine that matches either one of two machines |
| 446 | * |
| 447 | * synopsis |
| 448 | * |
| 449 | * new = mkor( first, second ); |
| 450 | * |
| 451 | * new - a machine which matches either first's pattern or second's |
| 452 | * first, second - machines whose patterns are to be or'ed (the | operator) |
| 453 | * |
| 454 | * note that first and second are both destroyed by the operation |
| 455 | * the code is rather convoluted because an attempt is made to minimize |
| 456 | * the number of epsilon states needed |
| 457 | */ |
| 458 | |
| 459 | int mkor( first, second ) |
| 460 | int first, second; |
| 461 | |
| 462 | { |
| 463 | int eps, orend; |
| 464 | |
| 465 | if ( first == NIL ) |
| 466 | return ( second ); |
| 467 | |
| 468 | else if ( second == NIL ) |
| 469 | return ( first ); |
| 470 | |
| 471 | else |
| 472 | { |
| 473 | /* see comment in mkopt() about why we can't use the first state |
| 474 | * of "first" or "second" if they satisfy "FREE_EPSILON" |
| 475 | */ |
| 476 | eps = mkstate( SYM_EPSILON ); |
| 477 | |
| 478 | first = link_machines( eps, first ); |
| 479 | |
| 480 | mkxtion( first, second ); |
| 481 | |
| 482 | if ( SUPER_FREE_EPSILON(finalst[first]) && |
| 483 | accptnum[finalst[first]] == NIL ) |
| 484 | { |
| 485 | orend = finalst[first]; |
| 486 | mkxtion( finalst[second], orend ); |
| 487 | } |
| 488 | |
| 489 | else if ( SUPER_FREE_EPSILON(finalst[second]) && |
| 490 | accptnum[finalst[second]] == NIL ) |
| 491 | { |
| 492 | orend = finalst[second]; |
| 493 | mkxtion( finalst[first], orend ); |
| 494 | } |
| 495 | |
| 496 | else |
| 497 | { |
| 498 | eps = mkstate( SYM_EPSILON ); |
| 499 | |
| 500 | first = link_machines( first, eps ); |
| 501 | orend = finalst[first]; |
| 502 | |
| 503 | mkxtion( finalst[second], orend ); |
| 504 | } |
| 505 | } |
| 506 | |
| 507 | finalst[first] = orend; |
| 508 | return ( first ); |
| 509 | } |
| 510 | |
| 511 | |
| 512 | /* mkposcl - convert a machine into a positive closure |
| 513 | * |
| 514 | * synopsis |
| 515 | * new = mkposcl( state ); |
| 516 | * |
| 517 | * new - a machine matching the positive closure of "state" |
| 518 | */ |
| 519 | |
| 520 | int mkposcl( state ) |
| 521 | int state; |
| 522 | |
| 523 | { |
| 524 | int eps; |
| 525 | |
| 526 | if ( SUPER_FREE_EPSILON(finalst[state]) ) |
| 527 | { |
| 528 | mkxtion( finalst[state], state ); |
| 529 | return ( state ); |
| 530 | } |
| 531 | |
| 532 | else |
| 533 | { |
| 534 | eps = mkstate( SYM_EPSILON ); |
| 535 | mkxtion( eps, state ); |
| 536 | return ( link_machines( state, eps ) ); |
| 537 | } |
| 538 | } |
| 539 | |
| 540 | |
| 541 | /* mkrep - make a replicated machine |
| 542 | * |
| 543 | * synopsis |
| 544 | * new = mkrep( mach, lb, ub ); |
| 545 | * |
| 546 | * new - a machine that matches whatever "mach" matched from "lb" |
| 547 | * number of times to "ub" number of times |
| 548 | * |
| 549 | * note |
| 550 | * if "ub" is INFINITY then "new" matches "lb" or more occurrences of "mach" |
| 551 | */ |
| 552 | |
| 553 | int mkrep( mach, lb, ub ) |
| 554 | int mach, lb, ub; |
| 555 | |
| 556 | { |
| 557 | int base_mach, tail, copy, i; |
| 558 | |
| 559 | base_mach = copysingl( mach, lb - 1 ); |
| 560 | |
| 561 | if ( ub == INFINITY ) |
| 562 | { |
| 563 | copy = dupmachine( mach ); |
| 564 | mach = link_machines( mach, |
| 565 | link_machines( base_mach, mkclos( copy ) ) ); |
| 566 | } |
| 567 | |
| 568 | else |
| 569 | { |
| 570 | tail = mkstate( SYM_EPSILON ); |
| 571 | |
| 572 | for ( i = lb; i < ub; ++i ) |
| 573 | { |
| 574 | copy = dupmachine( mach ); |
| 575 | tail = mkopt( link_machines( copy, tail ) ); |
| 576 | } |
| 577 | |
| 578 | mach = link_machines( mach, link_machines( base_mach, tail ) ); |
| 579 | } |
| 580 | |
| 581 | return ( mach ); |
| 582 | } |
| 583 | |
| 584 | |
| 585 | /* mkstate - create a state with a transition on a given symbol |
| 586 | * |
| 587 | * synopsis |
| 588 | * |
| 589 | * state = mkstate( sym ); |
| 590 | * |
| 591 | * state - a new state matching sym |
| 592 | * sym - the symbol the new state is to have an out-transition on |
| 593 | * |
| 594 | * note that this routine makes new states in ascending order through the |
| 595 | * state array (and increments LASTNFA accordingly). The routine DUPMACHINE |
| 596 | * relies on machines being made in ascending order and that they are |
| 597 | * CONTIGUOUS. Change it and you will have to rewrite DUPMACHINE (kludge |
| 598 | * that it admittedly is) |
| 599 | */ |
| 600 | |
| 601 | int mkstate( sym ) |
| 602 | int sym; |
| 603 | |
| 604 | { |
| 605 | if ( ++lastnfa >= current_mns ) |
| 606 | { |
| 607 | if ( (current_mns += MNS_INCREMENT) >= MAXIMUM_MNS ) |
| 608 | lerrif( "input rules are too complicated (>= %d NFA states)", |
| 609 | current_mns ); |
| 610 | |
| 611 | ++num_reallocs; |
| 612 | |
| 613 | firstst = reallocate_integer_array( firstst, current_mns ); |
| 614 | lastst = reallocate_integer_array( lastst, current_mns ); |
| 615 | finalst = reallocate_integer_array( finalst, current_mns ); |
| 616 | transchar = reallocate_integer_array( transchar, current_mns ); |
| 617 | trans1 = reallocate_integer_array( trans1, current_mns ); |
| 618 | trans2 = reallocate_integer_array( trans2, current_mns ); |
| 619 | accptnum = reallocate_integer_array( accptnum, current_mns ); |
| 620 | assoc_rule = reallocate_integer_array( assoc_rule, current_mns ); |
| 621 | state_type = reallocate_integer_array( state_type, current_mns ); |
| 622 | } |
| 623 | |
| 624 | firstst[lastnfa] = lastnfa; |
| 625 | finalst[lastnfa] = lastnfa; |
| 626 | lastst[lastnfa] = lastnfa; |
| 627 | transchar[lastnfa] = sym; |
| 628 | trans1[lastnfa] = NO_TRANSITION; |
| 629 | trans2[lastnfa] = NO_TRANSITION; |
| 630 | accptnum[lastnfa] = NIL; |
| 631 | assoc_rule[lastnfa] = num_rules; |
| 632 | state_type[lastnfa] = current_state_type; |
| 633 | |
| 634 | /* fix up equivalence classes base on this transition. Note that any |
| 635 | * character which has its own transition gets its own equivalence class. |
| 636 | * Thus only characters which are only in character classes have a chance |
| 637 | * at being in the same equivalence class. E.g. "a|b" puts 'a' and 'b' |
| 638 | * into two different equivalence classes. "[ab]" puts them in the same |
| 639 | * equivalence class (barring other differences elsewhere in the input). |
| 640 | */ |
| 641 | |
| 642 | if ( sym < 0 ) |
| 643 | { |
| 644 | /* we don't have to update the equivalence classes since that was |
| 645 | * already done when the ccl was created for the first time |
| 646 | */ |
| 647 | } |
| 648 | |
| 649 | else if ( sym == SYM_EPSILON ) |
| 650 | ++numeps; |
| 651 | |
| 652 | else |
| 653 | { |
| 654 | if ( useecs ) |
| 655 | /* map NUL's to csize */ |
| 656 | mkechar( sym ? sym : csize, nextecm, ecgroup ); |
| 657 | } |
| 658 | |
| 659 | return ( lastnfa ); |
| 660 | } |
| 661 | |
| 662 | |
| 663 | /* mkxtion - make a transition from one state to another |
| 664 | * |
| 665 | * synopsis |
| 666 | * |
| 667 | * mkxtion( statefrom, stateto ); |
| 668 | * |
| 669 | * statefrom - the state from which the transition is to be made |
| 670 | * stateto - the state to which the transition is to be made |
| 671 | */ |
| 672 | |
| 673 | void mkxtion( statefrom, stateto ) |
| 674 | int statefrom, stateto; |
| 675 | |
| 676 | { |
| 677 | if ( trans1[statefrom] == NO_TRANSITION ) |
| 678 | trans1[statefrom] = stateto; |
| 679 | |
| 680 | else if ( (transchar[statefrom] != SYM_EPSILON) || |
| 681 | (trans2[statefrom] != NO_TRANSITION) ) |
| 682 | flexfatal( "found too many transitions in mkxtion()" ); |
| 683 | |
| 684 | else |
| 685 | { /* second out-transition for an epsilon state */ |
| 686 | ++eps2; |
| 687 | trans2[statefrom] = stateto; |
| 688 | } |
| 689 | } |
| 690 | |
| 691 | /* new_rule - initialize for a new rule |
| 692 | * |
| 693 | * synopsis |
| 694 | * |
| 695 | * new_rule(); |
| 696 | * |
| 697 | * the global num_rules is incremented and the any corresponding dynamic |
| 698 | * arrays (such as rule_type[]) are grown as needed. |
| 699 | */ |
| 700 | |
| 701 | void new_rule() |
| 702 | |
| 703 | { |
| 704 | if ( ++num_rules >= current_max_rules ) |
| 705 | { |
| 706 | ++num_reallocs; |
| 707 | current_max_rules += MAX_RULES_INCREMENT; |
| 708 | rule_type = reallocate_integer_array( rule_type, current_max_rules ); |
| 709 | rule_linenum = |
| 710 | reallocate_integer_array( rule_linenum, current_max_rules ); |
| 711 | } |
| 712 | |
| 713 | if ( num_rules > MAX_RULE ) |
| 714 | lerrif( "too many rules (> %d)!", MAX_RULE ); |
| 715 | |
| 716 | rule_linenum[num_rules] = linenum; |
| 717 | } |