soltools/cpp/_lex.c

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #if (defined(_WIN32) || defined(__IBMC__))
  24 #include <io.h>
  25 #else
  26 #include <unistd.h>
  27 #endif
  28 #include "cpp.h"
  29 /*
  30  * lexical FSM encoding
  31  *   when in state state, and one of the characters
  32  *   in ch arrives, enter nextstate.
  33  *   States >= S_SELF are either final, or at least require special action.
  34  *   In 'fsm' there is a line for each state X charset X nextstate.
  35  *   List chars that overwrite previous entries later (e.g. C_ALPH
  36  *   can be overridden by '_' by a later entry; and C_XX is the
  37  *   universal set, and should always be first.
  38  *   States above S_SELF are represented in the big table as negative values.
  39  *   S_SELF and S_SELFB encode the resulting token type in the upper bits.
  40  *   These actions differ in that S_SELF doesn't have a lookahead char,
  41  *   S_SELFB does.
  42  *
  43  *   The encoding is blown out into a big table for time-efficiency.
  44  *   Entries have
  45  *      nextstate: 6 bits; ?\ marker: 1 bit; tokentype: 9 bits.
  46  */
  47
  48 #define MAXSTATE        32
  49 #define ACT(tok,act)    ((tok<<7)+act)
  50 #define QBSBIT          0100
  51 #define GETACT(st)      ((st>>7)&0x1ff)
  52
  53 /* character classes */
  54 #define C_ALPH  1
  55 #define C_NUM   2
  56 #define C_XX    3
  57
  58 enum state
  59 {
  60     START = 0, NUM1, NUM2, NUM3, ID1, ST1, ST2, ST3, COM1, COM2, COM3, COM4,
  61     CC1, CC2, WS1, PLUS1, MINUS1, STAR1, SLASH1, PCT1, SHARP1,
  62     CIRC1, GT1, GT2, LT1, LT2, OR1, AND1, ASG1, NOT1, DOTS1,
  63     S_SELF = MAXSTATE, S_SELFB, S_EOF, S_NL, S_EOFSTR,
  64     S_STNL, S_COMNL, S_EOFCOM, S_COMMENT, S_EOB, S_WS, S_NAME
  65 };
  66
  67 int tottok;
  68 int tokkind[256];
  69 struct fsm
  70 {
  71     int state;                          /* if in this state */
  72     uchar ch[4];                        /* and see one of these characters */
  73     int nextstate;                      /* enter this state if +ve */
  74 };
  75
  76 static /*const*/ struct fsm fsm[] = {
  77     /* start state */
  78          {START, {C_XX}, ACT(UNCLASS, S_SELF)},
  79          {START, {' ', '\t', '\v'}, WS1},
  80          {START, {C_NUM}, NUM1},
  81          {START, {'.'}, NUM3},
  82          {START, {C_ALPH}, ID1},
  83          {START, {'L'}, ST1},
  84          {START, {'"'}, ST2},
  85          {START, {'\''}, CC1},
  86          {START, {'/'}, COM1},
  87          {START, {EOFC}, S_EOF},
  88          {START, {'\n'}, S_NL},
  89          {START, {'-'}, MINUS1},
  90          {START, {'+'}, PLUS1},
  91          {START, {'<'}, LT1},
  92          {START, {'>'}, GT1},
  93          {START, {'='}, ASG1},
  94          {START, {'!'}, NOT1},
  95          {START, {'&'}, AND1},
  96          {START, {'|'}, OR1},
  97          {START, {'#'}, SHARP1},
  98          {START, {'%'}, PCT1},
  99          {START, {'['}, ACT(SBRA, S_SELF)},
 100          {START, {']'}, ACT(SKET, S_SELF)},
 101          {START, {'('}, ACT(LP, S_SELF)},
 102          {START, {')'}, ACT(RP, S_SELF)},
 103          {START, {'*'}, STAR1},
 104          {START, {','}, ACT(COMMA, S_SELF)},
 105          {START, {'?'}, ACT(QUEST, S_SELF)},
 106          {START, {':'}, ACT(COLON, S_SELF)},
 107          {START, {';'}, ACT(SEMIC, S_SELF)},
 108          {START, {'{'}, ACT(CBRA, S_SELF)},
 109          {START, {'}'}, ACT(CKET, S_SELF)},
 110          {START, {'~'}, ACT(TILDE, S_SELF)},
 111          {START, {'^'}, CIRC1},
 112
 113     /* saw a digit */
 114          {NUM1, {C_XX}, ACT(NUMBER, S_SELFB)},
 115          {NUM1, {C_NUM, C_ALPH, '.'}, NUM1},
 116          {NUM1, {'E', 'e'}, NUM2},
 117          {NUM1, {'_'}, ACT(NUMBER, S_SELFB)},
 118
 119     /* saw possible start of exponent, digits-e */
 120          {NUM2, {C_XX}, ACT(NUMBER, S_SELFB)},
 121          {NUM2, {'+', '-'}, NUM1},
 122          {NUM2, {C_NUM, C_ALPH}, NUM1},
 123          {NUM2, {'_'}, ACT(NUMBER, S_SELFB)},
 124
 125     /* saw a '.', which could be a number or an operator */
 126          {NUM3, {C_XX}, ACT(DOT, S_SELFB)},
 127          {NUM3, {'.'}, DOTS1},
 128          {NUM3, {C_NUM}, NUM1},
 129
 130          {DOTS1, {C_XX}, ACT(UNCLASS, S_SELFB)},
 131          {DOTS1, {C_NUM}, NUM1},
 132          {DOTS1, {'.'}, ACT(ELLIPS, S_SELF)},
 133
 134     /* saw a letter or _ */
 135          {ID1, {C_XX}, ACT(NAME, S_NAME)},
 136          {ID1, {C_ALPH, C_NUM}, ID1},
 137
 138     /* saw L (start of wide string?) */
 139          {ST1, {C_XX}, ACT(NAME, S_NAME)},
 140          {ST1, {C_ALPH, C_NUM}, ID1},
 141          {ST1, {'"'}, ST2},
 142          {ST1, {'\''}, CC1},
 143
 144     /* saw " beginning string */
 145          {ST2, {C_XX}, ST2},
 146          {ST2, {'"'}, ACT(STRING, S_SELF)},
 147          {ST2, {'\\'}, ST3},
 148          {ST2, {'\n'}, S_STNL},
 149          {ST2, {EOFC}, S_EOFSTR},
 150
 151     /* saw \ in string */
 152          {ST3, {C_XX}, ST2},
 153          {ST3, {'\n'}, S_STNL},
 154          {ST3, {EOFC}, S_EOFSTR},
 155
 156     /* saw ' beginning character const */
 157          {CC1, {C_XX}, CC1},
 158          {CC1, {'\''}, ACT(CCON, S_SELF)},
 159          {CC1, {'\\'}, CC2},
 160          {CC1, {'\n'}, S_STNL},
 161          {CC1, {EOFC}, S_EOFSTR},
 162
 163     /* saw \ in ccon */
 164          {CC2, {C_XX}, CC1},
 165          {CC2, {'\n'}, S_STNL},
 166          {CC2, {EOFC}, S_EOFSTR},
 167
 168     /* saw /, perhaps start of comment */
 169          {COM1, {C_XX}, ACT(SLASH, S_SELFB)},
 170          {COM1, {'='}, ACT(ASSLASH, S_SELF)},
 171          {COM1, {'*'}, COM2},
 172          {COM1, {'/'}, COM4},
 173
 174     /* saw / followed by *, start of comment */
 175          {COM2, {C_XX}, COM2},
 176          {COM2, {'\n'}, S_COMNL},
 177          {COM2, {'*'}, COM3},
 178          {COM2, {EOFC}, S_EOFCOM},
 179
 180     /* saw the * possibly ending a comment */
 181          {COM3, {C_XX}, COM2},
 182          {COM3, {'\n'}, S_COMNL},
 183          {COM3, {'*'}, COM3},
 184          {COM3, {'/'}, S_COMMENT},
 185
 186     /* // comment */
 187          {COM4, {C_XX}, COM4},
 188          {COM4, {'\n'}, S_NL},
 189          {COM4, {EOFC}, S_EOFCOM},
 190
 191     /* saw white space, eat it up */
 192          {WS1, {C_XX}, S_WS},
 193          {WS1, {'\t', '\v', ' '}, WS1},
 194
 195     /* saw -, check --, -=, -> */
 196          {MINUS1, {C_XX}, ACT(MINUS, S_SELFB)},
 197          {MINUS1, {'-'}, ACT(MMINUS, S_SELF)},
 198          {MINUS1, {'='}, ACT(ASMINUS, S_SELF)},
 199          {MINUS1, {'>'}, ACT(ARROW, S_SELF)},
 200
 201     /* saw +, check ++, += */
 202          {PLUS1, {C_XX}, ACT(PLUS, S_SELFB)},
 203          {PLUS1, {'+'}, ACT(PPLUS, S_SELF)},
 204          {PLUS1, {'='}, ACT(ASPLUS, S_SELF)},
 205
 206     /* saw <, check <<, <<=, <= */
 207          {LT1, {C_XX}, ACT(LT, S_SELFB)},
 208          {LT1, {'<'}, LT2},
 209          {LT1, {'='}, ACT(LEQ, S_SELF)},
 210          {LT2, {C_XX}, ACT(LSH, S_SELFB)},
 211          {LT2, {'='}, ACT(ASLSH, S_SELF)},
 212
 213     /* saw >, check >>, >>=, >= */
 214          {GT1, {C_XX}, ACT(GT, S_SELFB)},
 215          {GT1, {'>'}, GT2},
 216          {GT1, {'='}, ACT(GEQ, S_SELF)},
 217          {GT2, {C_XX}, ACT(RSH, S_SELFB)},
 218          {GT2, {'='}, ACT(ASRSH, S_SELF)},
 219
 220     /* = */
 221          {ASG1, {C_XX}, ACT(ASGN, S_SELFB)},
 222          {ASG1, {'='}, ACT(EQ, S_SELF)},
 223
 224     /* ! */
 225          {NOT1, {C_XX}, ACT(NOT, S_SELFB)},
 226          {NOT1, {'='}, ACT(NEQ, S_SELF)},
 227
 228     /* & */
 229          {AND1, {C_XX}, ACT(AND, S_SELFB)},
 230          {AND1, {'&'}, ACT(LAND, S_SELF)},
 231          {AND1, {'='}, ACT(ASAND, S_SELF)},
 232
 233     /* | */
 234          {OR1, {C_XX}, ACT(OR, S_SELFB)},
 235          {OR1, {'|'}, ACT(LOR, S_SELF)},
 236          {OR1, {'='}, ACT(ASOR, S_SELF)},
 237
 238     /* # */
 239          {SHARP1, {C_XX}, ACT(SHARP, S_SELFB)},
 240          {SHARP1, {'#'}, ACT(DSHARP, S_SELF)},
 241
 242     /* % */
 243          {PCT1, {C_XX}, ACT(PCT, S_SELFB)},
 244          {PCT1, {'='}, ACT(ASPCT, S_SELF)},
 245
 246     /* * */
 247          {STAR1, {C_XX}, ACT(STAR, S_SELFB)},
 248          {STAR1, {'='}, ACT(ASSTAR, S_SELF)},
 249
 250     /* ^ */
 251          {CIRC1, {C_XX}, ACT(CIRC, S_SELFB)},
 252          {CIRC1, {'='}, ACT(ASCIRC, S_SELF)},
 253
 254          {-1, "", 0}
 255 };
 256
 257 /* first index is char, second is state */
 258 /* increase #states to power of 2 to encourage use of shift */
 259 short bigfsm[256][MAXSTATE];
 260
 261 void
 262     expandlex(void)
 263 {
 264      /* const */ struct fsm *fp;
 265     int i, j, nstate;
 266
 267     for (fp = fsm; fp->state >= 0; fp++)
 268     {
 269         for (i = 0; fp->ch[i]; i++)
 270         {
 271             nstate = fp->nextstate;
 272             if (nstate >= S_SELF)
 273                 nstate = ~nstate;
 274             switch (fp->ch[i])
 275             {
 276
 277                 case C_XX:              /* random characters */
 278                     for (j = 0; j < 256; j++)
 279                         bigfsm[j][fp->state] = (short) nstate;
 280                     continue;
 281                 case C_ALPH:
 282                     for (j = 0; j < 256; j++)
 283                         if (('a' <= j && j <= 'z') || ('A' <= j && j <= 'Z')
 284                             || j == '_')
 285                             bigfsm[j][fp->state] = (short) nstate;
 286                     continue;
 287                 case C_NUM:
 288                     for (j = '0'; j <= '9'; j++)
 289                         bigfsm[j][fp->state] = (short) nstate;
 290                     continue;
 291                 default:
 292                     bigfsm[fp->ch[i]][fp->state] = (short) nstate;
 293             }
 294         }
 295     }
 296
 297     /*
 298      * install special cases for ? (trigraphs),  \ (splicing), runes, and
 299      * EOB
 300      */
 301     for (i = 0; i < MAXSTATE; i++)
 302     {
 303         for (j = 0; j < 0xFF; j++)
 304             if (j == '?' || j == '\\' || j == '\n' || j == '\r')
 305             {
 306                 if (bigfsm[j][i] > 0)
 307                     bigfsm[j][i] = ~bigfsm[j][i];
 308                 bigfsm[j][i] &= ~QBSBIT;
 309             }
 310         bigfsm[EOB][i] = ~S_EOB;
 311         if (bigfsm[EOFC][i] >= 0)
 312             bigfsm[EOFC][i] = ~S_EOF;
 313     }
 314 }
 315
 316 void
 317     fixlex(void)
 318 {
 319     /* do C++ comments? */
 320     if ((Cplusplus == 0) || (Cflag != 0))
 321         bigfsm['/'][COM1] = bigfsm['x'][COM1];
 322 }
 323
 324 /*
 325  * fill in a row of tokens from input, terminated by NL or END
 326  * First token is put at trp->lp.
 327  * Reset is non-zero when the input buffer can be "rewound."
 328  * The value is a flag indicating that possible macros have
 329  * been seen in the row.
 330  */
 331 int
 332     gettokens(Tokenrow * trp, int reset)
 333 {
 334     int c, state, oldstate;
 335     uchar *ip;
 336     Token *tp, *maxp;
 337     int runelen;
 338     Source *s = cursource;
 339     int nmac = 0;
 340
 341     tp = trp->lp;
 342     ip = s->inp;
 343     if (reset)
 344     {
 345         s->lineinc = 0;
 346         if (ip >= s->inl)
 347         {                               /* nothing in buffer */
 348             s->inl = s->inb;
 349             fillbuf(s);
 350             ip = s->inp = s->inb;
 351         }
 352         else
 353             if (ip >= s->inb + (3 * INS / 4))
 354             {
 355                 memmove(s->inb, ip, 4 + s->inl - ip);
 356                 s->inl = s->inb + (s->inl - ip);
 357                 ip = s->inp = s->inb;
 358             }
 359     }
 360     maxp = &trp->bp[trp->max];
 361     runelen = 1;
 362     for (;;)
 363     {
 364 continue2:
 365         if (tp >= maxp)
 366         {
 367             trp->lp = tp;
 368             tp = growtokenrow(trp);
 369             maxp = &trp->bp[trp->max];
 370         }
 371         tp->type = UNCLASS;
 372         tp->t = ip;
 373         tp->wslen = 0;
 374         tp->flag = 0;
 375         state = START;
 376         for (;;)
 377         {
 378             oldstate = state;
 379
 380             c = *ip;
 381
 382             if ((state = bigfsm[c][state]) >= 0)
 383             {
 384                 ip += runelen;
 385                 runelen = 1;
 386                 continue;
 387             }
 388             state = ~state;
 389     reswitch:
 390             switch (state & 0177)
 391             {
 392                 case S_SELF:
 393                     ip += runelen;
 394                     runelen = 1;
 395                     /*fall-through*/
 396                 case S_SELFB:
 397                     tp->type = (unsigned char) GETACT(state);
 398                     tp->len = ip - tp->t;
 399                     tp++;
 400                     goto continue2;
 401
 402                 case S_NAME:            /* like S_SELFB but with nmac check */
 403                     tp->type = NAME;
 404                     tp->len = ip - tp->t;
 405                     nmac |= quicklook(tp->t[0], tp->len > 1 ? tp->t[1] : 0);
 406                     tp++;
 407                     goto continue2;
 408
 409                 case S_WS:
 410                     tp->wslen = ip - tp->t;
 411                     tp->t = ip;
 412                     state = START;
 413                     continue;
 414
 415                 default:
 416                     if ((state & QBSBIT) == 0)
 417                     {
 418                         ip += runelen;
 419                         runelen = 1;
 420                         continue;
 421                     }
 422                     state &= ~QBSBIT;
 423                     s->inp = ip;
 424
 425                     if (c == '\n')
 426                     {
 427                         while (s->inp + 1 >= s->inl && fillbuf(s) != EOF);
 428
 429                         if (s->inp[1] == '\r')
 430                         {
 431                             memmove(s->inp + 1, s->inp + 2, s->inl - s->inp + 2);
 432                             s->inl -= 1;
 433                         }
 434
 435                         goto reswitch;
 436                     }
 437
 438                     if (c == '\r')
 439                     {
 440                         while (s->inp + 1 >= s->inl && fillbuf(s) != EOF);
 441
 442                         if (s->inp[1] == '\n')
 443                         {
 444                             memmove(s->inp, s->inp + 1, s->inl - s->inp + 1);
 445                             s->inl -= 1;
 446                         }
 447                         else
 448                             *s->inp = '\n';
 449
 450                         state = oldstate;
 451                         continue;
 452                     }
 453
 454                     if (c == '?')
 455                     {                   /* check trigraph */
 456                         if (trigraph(s))
 457                         {
 458                             state = oldstate;
 459                             continue;
 460                         }
 461                         goto reswitch;
 462                     }
 463                     if (c == '\\')
 464                     {                   /* line-folding */
 465                         if (foldline(s))
 466                         {
 467                             s->lineinc++;
 468                             state = oldstate;
 469                             continue;
 470                         }
 471                         goto reswitch;
 472                     }
 473                     error(WARNING, "Lexical botch in cpp");
 474                     ip += runelen;
 475                     runelen = 1;
 476                     continue;
 477
 478                 case S_EOB:
 479                     s->inp = ip;
 480                     fillbuf(cursource);
 481                     state = oldstate;
 482                     continue;
 483
 484                 case S_EOF:
 485                     tp->type = END;
 486                     tp->len = 0;
 487                     s->inp = ip;
 488                     if (tp != trp->bp && (tp - 1)->type != NL && cursource->fd != -1)
 489                         error(WARNING, "No newline at end of file");
 490                     trp->lp = tp + 1;
 491                     return nmac;
 492
 493                 case S_STNL:
 494                     error(ERROR, "Unterminated string or char const");
 495                     /* fall through */
 496                 case S_NL:
 497                     tp->t = ip;
 498                     tp->type = NL;
 499                     tp->len = 1;
 500                     tp->wslen = 0;
 501                     s->lineinc++;
 502                     s->inp = ip + 1;
 503                     trp->lp = tp + 1;
 504                     return nmac;
 505
 506                 case S_EOFSTR:
 507                     error(FATAL, "EOF in string or char constant");
 508                     break;
 509
 510                 case S_COMNL:
 511                     s->lineinc++;
 512                     state = COM2;
 513                     ip += runelen;
 514                     runelen = 1;
 515                     continue;
 516
 517                 case S_EOFCOM:
 518                     error(WARNING, "EOF inside comment");
 519                     --ip;
 520                     /* fall through */
 521                 case S_COMMENT:
 522                     if (!Cflag)
 523                     {
 524                         tp->t = ++ip;
 525                         tp->t[-1] = ' ';
 526                         tp->wslen = 1;
 527                         state = START;
 528                         continue;
 529                     }
 530                     else
 531                     {
 532                         runelen = 1;
 533                         s->lineinc = 0;
 534                         tp->type = COMMENT;
 535                         tp->flag |= XTWS;
 536                     }
 537             }
 538             break;
 539         }
 540         ip += runelen;
 541         runelen = 1;
 542         tp->len = ip - tp->t;
 543         tp++;
 544     }
 545 }
 546
 547 /* have seen ?; handle the trigraph it starts (if any) else 0 */
 548 int
 549     trigraph(Source * s)
 550 {
 551     uchar c;
 552
 553     while (s->inp + 2 >= s->inl && fillbuf(s) != EOF);
 554     ;
 555     if (s->inp[1] != '?')
 556         return 0;
 557     c = 0;
 558     switch (s->inp[2])
 559     {
 560         case '=':
 561             c = '#';
 562             break;
 563         case '(':
 564             c = '[';
 565             break;
 566         case '/':
 567             c = '\\';
 568             break;
 569         case ')':
 570             c = ']';
 571             break;
 572         case '\'':
 573             c = '^';
 574             break;
 575         case '<':
 576             c = '{';
 577             break;
 578         case '!':
 579             c = '|';
 580             break;
 581         case '>':
 582             c = '}';
 583             break;
 584         case '-':
 585             c = '~';
 586             break;
 587     }
 588     if (c)
 589     {
 590         *s->inp = c;
 591         memmove(s->inp + 1, s->inp + 3, s->inl - s->inp + 2);
 592         s->inl -= 2;
 593     }
 594     return c;
 595 }
 596
 597 int
 598     foldline(Source * s)
 599 {
 600     int n = 1;
 601
 602     /* skip pending white spaces */
 603     while ((s->inp[n] == ' ') || (s->inp[n] == '\t'))
 604     {
 605         n++;
 606         if ((s->inp + n >= s->inl) && (fillbuf(s) == EOF))
 607             break;
 608     }
 609
 610     /* refill buffer */
 611     while (s->inp + (n + 1) >= s->inl && fillbuf(s) != EOF);
 612
 613     /* skip DOS line ends */
 614     if (((s->inp[n] == '\r') && (s->inp[n+1] == '\n')) ||
 615         ((s->inp[n] == '\n') && (s->inp[n+1] == '\r')))
 616         n++;
 617
 618     if ((s->inp[n] == '\n') || (s->inp[n] == '\r'))
 619     {
 620         memmove(s->inp, s->inp + n + 1, s->inl - s->inp + n + 2);
 621         s->inl -= n + 1;
 622         return 1;
 623     }
 624     return 0;
 625 }
 626
 627 int
 628     fillbuf(Source * s)
 629 {
 630     int n;
 631
 632     if (s->fd < 0 || (n = read(s->fd, (char *) s->inl, INS / 8)) <= 0)
 633         n = 0;
 634     s->inl += n;
 635     s->inl[0] = s->inl[1] = s->inl[2] = s->inl[3] = EOB;
 636     if (n == 0)
 637     {
 638         s->inl[0] = s->inl[1] = s->inl[2] = s->inl[3] = EOFC;
 639         return EOF;
 640     }
 641     return 0;
 642 }
 643
 644 /*
 645  * Push down to new source of characters.
 646  * If fd>0 and str==NULL, then from a file `name';
 647  * if fd==-1 and str, then from the string.
 648  */
 649 Source *
 650     setsource(char *name, int path, int fd, char *str, int wrap)
 651 {
 652     Source *s = new(Source);
 653     size_t len;
 654
 655     s->line = 1;
 656     s->lineinc = 0;
 657     s->fd = fd;
 658     s->filename = name;
 659     s->next = cursource;
 660     s->ifdepth = 0;
 661     s->pathdepth = path;
 662     s->wrap = wrap;
 663
 664     cursource = s;
 665
 666     if (s->wrap)
 667         genwrap(0);
 668
 669     /* slop at right for EOB */
 670     if (str)
 671     {
 672         len = strlen(str);
 673         s->inb = domalloc(len + 4);
 674         s->inp = s->inb;
 675         strncpy((char *) s->inp, str, len);
 676     }
 677     else
 678     {
 679         s->inb = domalloc(INS + 4);
 680         s->inp = s->inb;
 681         len = 0;
 682     }
 683     s->inl = s->inp + len;
 684     s->inl[0] = s->inl[1] = EOB;
 685
 686     return s;
 687 }
 688
 689 void
 690     unsetsource(void)
 691 {
 692     Source *s = cursource;
 693
 694     if (s->wrap)
 695         genwrap(1);
 696
 697     if (s->fd >= 0)
 698     {
 699         close(s->fd);
 700         dofree(s->inb);
 701     }
 702     cursource = s->next;
 703     dofree(s);
 704 }
 705
 706 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */