diplodocus.org Git - nmh/blob - uip/picksbr.c

   1 /* picksbr.c -- routines to help pick along...
   2  *
   3  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   4  * COPYRIGHT file in the root directory of the nmh distribution for
   5  * complete copyright information.
   6  */
   7
   8 #include <h/mh.h>
   9 #include <h/tws.h>
  10 #include <h/picksbr.h>
  11 #include <h/utils.h>
  12
  13 #ifdef HAVE_SYS_TIME_H
  14 # include <sys/time.h>
  15 #endif
  16 #include <time.h>
  17
  18 #define PARSE_SWITCHES \
  19     X("and", 0, PRAND) \
  20     X("or", 0, PROR) \
  21     X("not", 0, PRNOT) \
  22     X("lbrace", 0, PRLBR) \
  23     X("rbrace", 0, PRRBR) \
  24     X("cc  pattern", 0, PRCC) \
  25     X("date  pattern", 0, PRDATE) \
  26     X("from  pattern", 0, PRFROM) \
  27     X("search  pattern", 0, PRSRCH) \
  28     X("subject  pattern", 0, PRSUBJ) \
  29     X("to  pattern", 0, PRTO) \
  30     X("-othercomponent  pattern", 15, PROTHR) \
  31     X("after date", 0, PRAFTR) \
  32     X("before date", 0, PRBEFR) \
  33     X("datefield field", 5, PRDATF) \
  34
  35 #define X(sw, minchars, id) id,
  36 DEFINE_SWITCH_ENUM(PARSE);
  37 #undef X
  38
  39 #define X(sw, minchars, id) { sw, minchars, id },
  40 DEFINE_SWITCH_ARRAY(PARSE, parswit);
  41 #undef X
  42
  43 /* DEFINITIONS FOR PATTERN MATCHING */
  44
  45 /*
  46  * We really should be using re_comp() and re_exec() here.  Unfortunately,
  47  * pick advertises that lowercase characters matches characters of both
  48  * cases.  Since re_exec() doesn't exhibit this behavior, we are stuck
  49  * with this version.  Furthermore, we need to be able to save and restore
  50  * the state of the pattern matcher in order to do things "efficiently".
  51  *
  52  * The matching power of this algorithm isn't as powerful as the re_xxx()
  53  * routines (no \(xxx\) and \n constructs).  Such is life.
  54  */
  55
  56 #define CCHR    2
  57 #define CDOT    4
  58 #define CCL     6
  59 #define NCCL    8
  60 #define CDOL    10
  61 #define CEOF    11
  62
  63 #define STAR    01
  64
  65 #define LBSIZE  NMH_BUFSIZ
  66 #define ESIZE   1024
  67
  68
  69 static char linebuf[LBSIZE + 1];
  70 static char decoded_linebuf[LBSIZE + 1];
  71
  72 /* the magic array for case-independence */
  73 static unsigned char cc[] = {
  74         0000,0001,0002,0003,0004,0005,0006,0007,
  75         0010,0011,0012,0013,0014,0015,0016,0017,
  76         0020,0021,0022,0023,0024,0025,0026,0027,
  77         0030,0031,0032,0033,0034,0035,0036,0037,
  78         0040,0041,0042,0043,0044,0045,0046,0047,
  79         0050,0051,0052,0053,0054,0055,0056,0057,
  80         0060,0061,0062,0063,0064,0065,0066,0067,
  81         0070,0071,0072,0073,0074,0075,0076,0077,
  82         0100,0141,0142,0143,0144,0145,0146,0147,
  83         0150,0151,0152,0153,0154,0155,0156,0157,
  84         0160,0161,0162,0163,0164,0165,0166,0167,
  85         0170,0171,0172,0133,0134,0135,0136,0137,
  86         0140,0141,0142,0143,0144,0145,0146,0147,
  87         0150,0151,0152,0153,0154,0155,0156,0157,
  88         0160,0161,0162,0163,0164,0165,0166,0167,
  89         0170,0171,0172,0173,0174,0175,0176,0177,
  90
  91         0200,0201,0202,0203,0204,0205,0206,0207,
  92         0210,0211,0212,0213,0214,0215,0216,0217,
  93         0220,0221,0222,0223,0224,0225,0226,0227,
  94         0230,0231,0232,0233,0234,0235,0236,0237,
  95         0240,0241,0242,0243,0244,0245,0246,0247,
  96         0250,0251,0252,0253,0254,0255,0256,0257,
  97         0260,0261,0262,0263,0264,0265,0266,0267,
  98         0270,0271,0272,0273,0274,0275,0276,0277,
  99         0300,0301,0302,0303,0304,0305,0306,0307,
 100         0310,0311,0312,0313,0314,0315,0316,0317,
 101         0320,0321,0322,0323,0324,0325,0326,0327,
 102         0330,0331,0332,0333,0334,0335,0336,0337,
 103         0340,0341,0342,0343,0344,0345,0346,0347,
 104         0350,0351,0352,0353,0354,0355,0356,0357,
 105         0360,0361,0362,0363,0364,0365,0366,0367,
 106         0370,0371,0372,0373,0374,0375,0376,0377,
 107 };
 108
 109 /*
 110  * DEFINITIONS FOR NEXUS
 111  */
 112
 113 #define nxtarg()        (*argp ? *argp++ : NULL)
 114 #define prvarg()        argp--
 115
 116 #define pinform         if (!talked++) inform
 117
 118 struct nexus {
 119     int (*n_action)();
 120
 121     union {
 122         /* for {OR,AND,NOT}action */
 123         struct {
 124             struct nexus *un_L_child;
 125             struct nexus *un_R_child;
 126         } st1;
 127
 128         /* for GREPaction */
 129         struct {
 130             int   un_header;
 131             int   un_circf;
 132             char  un_expbuf[ESIZE];
 133             char *un_patbuf;
 134         } st2;
 135
 136         /* for TWSaction */
 137         struct {
 138             char *un_datef;
 139             int   un_after;
 140             struct tws un_tws;
 141         } st3;
 142     } un;
 143 };
 144
 145 #define n_L_child un.st1.un_L_child
 146 #define n_R_child un.st1.un_R_child
 147
 148 #define n_header un.st2.un_header
 149 #define n_circf  un.st2.un_circf
 150 #define n_expbuf un.st2.un_expbuf
 151 #define n_patbuf un.st2.un_patbuf
 152
 153 #define n_datef  un.st3.un_datef
 154 #define n_after  un.st3.un_after
 155 #define n_tws    un.st3.un_tws
 156
 157 static int talked;
 158
 159 static char *datesw;
 160 static char **argp;
 161
 162 static struct nexus *head;
 163
 164 /*
 165  * prototypes for date routines
 166  */
 167 static struct tws *tws_parse(char *, int);
 168 static struct tws *tws_special(char *);
 169
 170 /*
 171  * static prototypes
 172  */
 173 static void PRaction(struct nexus *, int);
 174 static int gcompile(struct nexus *, char *);
 175 static int advance(char *, char *);
 176 static int cclass(unsigned char *, int, int);
 177 static int tcompile(char *, struct tws *, int);
 178
 179 static struct nexus *parse(void);
 180 static struct nexus *nexp1(void);
 181 static struct nexus *nexp2(void);
 182 static struct nexus *nexp3(void);
 183 static struct nexus *newnexus(int (*)(struct nexus *n,
 184     FILE *fp, int msgnum, long start, long stop));
 185
 186 static int ORaction(struct nexus *n, FILE *fp, int msgnum,
 187     long start, long stop);
 188 static int ANDaction(struct nexus *n, FILE *fp, int msgnum,
 189     long start, long stop);
 190 static int NOTaction(struct nexus *n, FILE *fp, int msgnum,
 191     long start, long stop);
 192 static int GREPaction(struct nexus *n, FILE *fp, int msgnum,
 193     long start, long stop);
 194 static int TWSaction(struct nexus *n, FILE *fp, int msgnum,
 195     long start, long stop);
 196
 197
 198 int
 199 pcompile (char **vec, char *date)
 200 {
 201     argp = vec;
 202     if ((datesw = date) == NULL)
 203         datesw = "date";
 204     talked = 0;
 205
 206     if ((head = parse ()) == NULL)
 207         return !talked;
 208
 209     if (*argp) {
 210         inform("%s unexpected", *argp);
 211         return 0;
 212     }
 213
 214     return 1;
 215 }
 216
 217
 218 static struct nexus *
 219 parse (void)
 220 {
 221     char  *cp;
 222     struct nexus *n, *o;
 223
 224     if ((n = nexp1 ()) == NULL || (cp = nxtarg ()) == NULL)
 225         return n;
 226
 227     if (*cp != '-') {
 228         pinform("%s unexpected", cp);
 229         return NULL;
 230     }
 231
 232     if (*++cp == '-')
 233         goto header;
 234     switch (smatch (cp, parswit)) {
 235         case AMBIGSW:
 236             ambigsw (cp, parswit);
 237             talked++;
 238             return NULL;
 239         case UNKWNSW:
 240             fprintf (stderr, "-%s unknown\n", cp);
 241             talked++;
 242             return NULL;
 243
 244         case PROR:
 245             o = newnexus (ORaction);
 246             o->n_L_child = n;
 247             if ((o->n_R_child = parse ()))
 248                 return o;
 249             pinform("missing disjunctive");
 250             free (o);
 251             return NULL;
 252
 253 header: ;
 254         default:
 255             prvarg ();
 256             return n;
 257     }
 258 }
 259
 260 static struct nexus *
 261 nexp1 (void)
 262 {
 263     char *cp;
 264     struct nexus *n, *o;
 265
 266     if ((n = nexp2 ()) == NULL || (cp = nxtarg ()) == NULL)
 267         return n;
 268
 269     if (*cp != '-') {
 270         pinform("%s unexpected", cp);
 271         free (n);
 272         return NULL;
 273     }
 274
 275     if (*++cp == '-')
 276         goto header;
 277     switch (smatch (cp, parswit)) {
 278         case AMBIGSW:
 279             ambigsw (cp, parswit);
 280             talked++;
 281             free (n);
 282             return NULL;
 283         case UNKWNSW:
 284             fprintf (stderr, "-%s unknown\n", cp);
 285             talked++;
 286             free (n);
 287             return NULL;
 288
 289         case PRAND:
 290             o = newnexus (ANDaction);
 291             o->n_L_child = n;
 292             if ((o->n_R_child = nexp1 ()))
 293                 return o;
 294             pinform("missing conjunctive");
 295             free (o);
 296             return NULL;
 297
 298 header: ;
 299         default:
 300             prvarg ();
 301             return n;
 302     }
 303 }
 304
 305
 306 static struct nexus *
 307 nexp2 (void)
 308 {
 309     char *cp;
 310     struct nexus *n;
 311
 312     if ((cp = nxtarg ()) == NULL)
 313         return NULL;
 314
 315     if (*cp != '-') {
 316         prvarg ();
 317         return nexp3 ();
 318     }
 319
 320     if (*++cp == '-')
 321         goto header;
 322     switch (smatch (cp, parswit)) {
 323         case AMBIGSW:
 324             ambigsw (cp, parswit);
 325             talked++;
 326             return NULL;
 327         case UNKWNSW:
 328             fprintf (stderr, "-%s unknown\n", cp);
 329             talked++;
 330             return NULL;
 331
 332         case PRNOT:
 333             n = newnexus (NOTaction);
 334             if ((n->n_L_child = nexp3 ()))
 335                 return n;
 336             pinform("missing negation");
 337             free (n);
 338             return NULL;
 339
 340 header: ;
 341         default:
 342             prvarg ();
 343             return nexp3 ();
 344     }
 345 }
 346
 347 static struct nexus *
 348 nexp3 (void)
 349 {
 350     int i;
 351     char *cp, *dp;
 352     char buffer[BUFSIZ], temp[64];
 353     struct nexus *n;
 354
 355     if ((cp = nxtarg ()) == NULL)
 356         return NULL;
 357
 358     if (*cp != '-') {
 359         pinform("%s unexpected", cp);
 360         return NULL;
 361     }
 362
 363     if (*++cp == '-') {
 364         dp = ++cp;
 365         goto header;
 366     }
 367     switch (i = smatch (cp, parswit)) {
 368         case AMBIGSW:
 369             ambigsw (cp, parswit);
 370             talked++;
 371             return NULL;
 372         case UNKWNSW:
 373             fprintf (stderr, "-%s unknown\n", cp);
 374             talked++;
 375             return NULL;
 376
 377         case PRLBR:
 378             if ((n = parse ()) == NULL) {
 379                 pinform("missing group");
 380                 return NULL;
 381             }
 382             if ((cp = nxtarg ()) == NULL) {
 383                 pinform("missing -rbrace");
 384                 return NULL;
 385             }
 386             if (*cp++ == '-' && smatch (cp, parswit) == PRRBR)
 387                 return n;
 388             pinform("%s unexpected", --cp);
 389             return NULL;
 390
 391         default:
 392             prvarg ();
 393             return NULL;
 394
 395         case PRCC:
 396         case PRDATE:
 397         case PRFROM:
 398         case PRTO:
 399         case PRSUBJ:
 400             strncpy(temp, parswit[i].sw, sizeof(temp));
 401             temp[sizeof(temp) - 1] = '\0';
 402             dp = *brkstring (temp, " ", NULL);
 403     header: ;
 404             if (!(cp = nxtarg ())) {/* allow -xyz arguments */
 405                 pinform("missing argument to %s", argp[-2]);
 406                 return NULL;
 407             }
 408             n = newnexus (GREPaction);
 409             n->n_header = 1;
 410             snprintf (buffer, sizeof(buffer), "^%s[ \t]*:.*%s", dp, cp);
 411             dp = buffer;
 412             goto pattern;
 413
 414         case PRSRCH:
 415             n = newnexus (GREPaction);
 416             n->n_header = 0;
 417             if (!(cp = nxtarg ())) {/* allow -xyz arguments */
 418                 pinform("missing argument to %s", argp[-2]);
 419                 free (n);
 420                 return NULL;
 421             }
 422             dp = cp;
 423     pattern: ;
 424             if (!gcompile (n, dp)) {
 425                 pinform("pattern error in %s %s", argp[-2], cp);
 426                 free (n);
 427                 return NULL;
 428             }
 429             n->n_patbuf = mh_xstrdup(dp);
 430             return n;
 431
 432         case PROTHR:
 433             pinform("internal error!");
 434             return NULL;
 435
 436         case PRDATF:
 437             if (!(datesw = nxtarg ()) || *datesw == '-') {
 438                 pinform("missing argument to %s", argp[-2]);
 439                 return NULL;
 440             }
 441             return nexp3 ();
 442
 443         case PRAFTR:
 444         case PRBEFR:
 445             if (!(cp = nxtarg ())) {/* allow -xyz arguments */
 446                 pinform("missing argument to %s", argp[-2]);
 447                 return NULL;
 448             }
 449             n = newnexus (TWSaction);
 450             n->n_datef = datesw;
 451             if (!tcompile (cp, &n->n_tws, n->n_after = i == PRAFTR)) {
 452                 pinform("unable to parse %s %s", argp[-2], cp);
 453                 free (n);
 454                 return NULL;
 455             }
 456             return n;
 457     }
 458 }
 459
 460
 461 static struct nexus *
 462 newnexus(int (*action)(struct nexus *n, FILE *fp, int msgnum,
 463     long start, long stop))
 464 {
 465     struct nexus *p;
 466
 467     NEW0(p);
 468     p->n_action = action;
 469     return p;
 470 }
 471
 472
 473 int
 474 pmatches (FILE *fp, int msgnum, long start, long stop, int debug)
 475 {
 476     if (!head)
 477         return 1;
 478
 479     if (!talked++ && debug)
 480         PRaction (head, 0);
 481
 482     return (*head->n_action)(head, fp, msgnum, start, stop);
 483 }
 484
 485
 486 static void
 487 PRaction (struct nexus *n, int level)
 488 {
 489     int i;
 490
 491     for (i = 0; i < level; i++)
 492         fprintf (stderr, "| ");
 493
 494     if (n->n_action == ORaction) {
 495         fprintf (stderr, "OR\n");
 496         PRaction (n->n_L_child, level + 1);
 497         PRaction (n->n_R_child, level + 1);
 498         return;
 499     }
 500     if (n->n_action == ANDaction) {
 501         fprintf (stderr, "AND\n");
 502         PRaction (n->n_L_child, level + 1);
 503         PRaction (n->n_R_child, level + 1);
 504         return;
 505     }
 506     if (n->n_action == NOTaction) {
 507         fprintf (stderr, "NOT\n");
 508         PRaction (n->n_L_child, level + 1);
 509         return;
 510     }
 511     if (n->n_action == GREPaction) {
 512         fprintf (stderr, "PATTERN(%s) %s\n",
 513                 n->n_header ? "header" : "body", n->n_patbuf);
 514         return;
 515     }
 516     if (n->n_action == TWSaction) {
 517         fprintf (stderr, "TEMPORAL(%s) %s: %s\n",
 518                 n->n_after ? "after" : "before", n->n_datef,
 519                 dasctime (&n->n_tws, TW_NULL));
 520         return;
 521     }
 522     fprintf (stderr, "UNKNOWN(0x%x)\n",
 523              (unsigned int)(unsigned long) (*n->n_action));
 524 }
 525
 526
 527 static int
 528 ORaction(struct nexus *n, FILE *fp, int msgnum, long start, long stop)
 529 {
 530     if ((*n->n_L_child->n_action)(n->n_L_child, fp, msgnum, start, stop))
 531         return 1;
 532     return (*n->n_R_child->n_action)(n->n_R_child, fp, msgnum, start, stop);
 533 }
 534
 535
 536 static int
 537 ANDaction(struct nexus *n, FILE *fp, int msgnum, long start, long stop)
 538 {
 539     if (!(*n->n_L_child->n_action)(n->n_L_child, fp, msgnum, start, stop))
 540         return 0;
 541     return (*n->n_R_child->n_action)(n->n_R_child, fp, msgnum, start, stop);
 542 }
 543
 544
 545 static int
 546 NOTaction(struct nexus *n, FILE *fp, int msgnum, long start, long stop)
 547 {
 548     return (!(*n->n_L_child->n_action)(n->n_L_child, fp, msgnum, start, stop));
 549 }
 550
 551
 552 static int
 553 gcompile (struct nexus *n, char *astr)
 554 {
 555     int c;
 556     int cclcnt;
 557     unsigned char *ep, *dp, *sp, *lastep = 0;
 558
 559     dp = (ep = (unsigned char *) n->n_expbuf) + sizeof n->n_expbuf;
 560     sp = (unsigned char *) astr;
 561     if (*sp == '^') {
 562         n->n_circf = 1;
 563         sp++;
 564     }
 565     else
 566         n->n_circf = 0;
 567     for (;;) {
 568         if (ep >= dp)
 569             goto cerror;
 570         if ((c = *sp++) != '*')
 571             lastep = ep;
 572         switch (c) {
 573             case '\0':
 574                 *ep++ = CEOF;
 575                 return 1;
 576
 577             case '.':
 578                 *ep++ = CDOT;
 579                 continue;
 580
 581             case '*':
 582                 if (lastep == 0)
 583                     goto defchar;
 584                 *lastep |= STAR;
 585                 continue;
 586
 587             case '$':
 588                 if (*sp != '\0')
 589                     goto defchar;
 590                 *ep++ = CDOL;
 591                 continue;
 592
 593             case '[':
 594                 *ep++ = CCL;
 595                 *ep++ = 0;
 596                 cclcnt = 0;
 597                 if ((c = *sp++) == '^') {
 598                     c = *sp++;
 599                     ep[-2] = NCCL;
 600                 }
 601                 if (c == '-') {
 602                     *ep++ = c;
 603                     cclcnt++;
 604                     c = *sp++;
 605                 }
 606                 do {
 607                     if (c == '-' && *sp != '\0' && *sp != ']') {
 608                         for (c = ep[-1]+1; c < *sp; c++) {
 609                             *ep++ = c;
 610                             cclcnt++;
 611                             if (c == '\0' || ep >= dp)
 612                                 goto cerror;
 613                         }
 614                     } else {
 615                         *ep++ = c;
 616                         cclcnt++;
 617                         if (c == '\0' || ep >= dp)
 618                             goto cerror;
 619                     }
 620                 } while ((c = *sp++) != ']');
 621                 if (cclcnt > 255)
 622                     goto cerror;
 623                 lastep[1] = cclcnt;
 624                 continue;
 625
 626             case '\\':
 627                 if ((c = *sp++) == '\0')
 628                     goto cerror;
 629                 /* FALLTHRU */
 630         defchar:
 631             default:
 632                 *ep++ = CCHR;
 633                 *ep++ = c;
 634         }
 635     }
 636
 637 cerror: ;
 638     return 0;
 639 }
 640
 641
 642 static int
 643 GREPaction(struct nexus *n, FILE *fp, int msgnum, long start, long stop)
 644 {
 645     int c, body, lf;
 646     long pos = start;
 647     char *p1, *p2, *ebp, *cbp;
 648     char ibuf[BUFSIZ];
 649     NMH_UNUSED (msgnum);
 650
 651     fseek (fp, start, SEEK_SET);
 652     body = 0;
 653     ebp = cbp = ibuf;
 654     for (;;) {
 655         if (body && n->n_header)
 656             return 0;
 657         p1 = linebuf;
 658         p2 = cbp;
 659         lf = 0;
 660         for (;;) {
 661             if (p2 >= ebp) {
 662                 if (fgets (ibuf, sizeof ibuf, fp) == NULL
 663                         || (stop && pos >= stop)) {
 664                     if (lf)
 665                         break;
 666                     return 0;
 667                 }
 668                 pos += (long) strlen (ibuf);
 669                 p2 = ibuf;
 670                 ebp = ibuf + strlen (ibuf);
 671             }
 672             c = *p2++;
 673             if (lf && c != '\n') {
 674                 if (c != ' ' && c != '\t') {
 675                     --p2;
 676                     break;
 677                 }
 678                 lf = 0;
 679             }
 680             if (c == '\n') {
 681                 if (body)
 682                     break;
 683                 if (lf) {
 684                     body++;
 685                     break;
 686                 }
 687                 lf++;
 688                 /* Unfold by skipping the newline. */
 689                 c = 0;
 690             }
 691             if (c && p1 < &linebuf[LBSIZE - 1])
 692                 *p1++ = c;
 693         }
 694
 695         *p1++ = 0;
 696         cbp = p2;
 697         p1 = linebuf;
 698         p2 = n->n_expbuf;
 699
 700         /* Attempt to decode as a MIME header.  If it's the last header,
 701            body will be 1 and lf will be at least 1. */
 702         if ((body == 0 || lf > 0)  &&
 703             decode_rfc2047 (linebuf, decoded_linebuf, sizeof decoded_linebuf)) {
 704             p1 = decoded_linebuf;
 705         }
 706
 707         if (n->n_circf) {
 708             if (advance (p1, p2))
 709                 return 1;
 710             continue;
 711         }
 712
 713         if (*p2 == CCHR) {
 714             c = p2[1];
 715             do {
 716                 if (*p1 == c || cc[(unsigned char)*p1] == c)
 717                     if (advance (p1, p2))
 718                         return 1;
 719             } while (*p1++);
 720             continue;
 721         }
 722
 723         do {
 724             if (advance (p1, p2))
 725                 return 1;
 726         } while (*p1++);
 727     }
 728 }
 729
 730
 731 static int
 732 advance (char *alp, char *aep)
 733 {
 734     unsigned char *lp, *ep, *curlp;
 735
 736     lp = (unsigned char *)alp;
 737     ep = (unsigned char *)aep;
 738     for (;;)
 739         switch (*ep++) {
 740             case CCHR:
 741                 if (*ep++ == *lp++ || ep[-1] == cc[lp[-1]])
 742                     continue;
 743                 return 0;
 744
 745             case CDOT:
 746                 if (*lp++)
 747                     continue;
 748                 return 0;
 749
 750             case CDOL:
 751                 if (*lp == 0)
 752                     continue;
 753                 return 0;
 754
 755             case CEOF:
 756                 return 1;
 757
 758             case CCL:
 759                 if (cclass (ep, *lp++, 1)) {
 760                     ep += *ep + 1;
 761                     continue;
 762                 }
 763                 return 0;
 764
 765             case NCCL:
 766                 if (cclass (ep, *lp++, 0)) {
 767                     ep += *ep + 1;
 768                     continue;
 769                 }
 770                 return 0;
 771
 772             case CDOT | STAR:
 773                 curlp = lp;
 774                 while (*lp++)
 775                     continue;
 776                 goto star;
 777
 778             case CCHR | STAR:
 779                 curlp = lp;
 780                 while (*lp++ == *ep || cc[lp[-1]] == *ep)
 781                     continue;
 782                 ep++;
 783                 goto star;
 784
 785             case CCL | STAR:
 786             case NCCL | STAR:
 787                 curlp = lp;
 788                 while (cclass (ep, *lp++, ep[-1] == (CCL | STAR)))
 789                     continue;
 790                 ep += *ep + 1;
 791                 goto star;
 792
 793         star:
 794                 do {
 795                     lp--;
 796                     if (advance ((char *) lp, (char *) ep))
 797                         return (1);
 798                 } while (lp > curlp);
 799                 return 0;
 800
 801             default:
 802                 inform("advance() botch -- you lose big, continuing...");
 803                 return 0;
 804         }
 805 }
 806
 807
 808 static int
 809 cclass (unsigned char *aset, int ac, int af)
 810 {
 811     unsigned int    n;
 812     unsigned char   c, *set;
 813
 814     set = aset;
 815     if ((c = ac) == 0)
 816         return (0);
 817
 818     n = *set++;
 819     while (n--)
 820         if (*set++ == c || set[-1] == cc[c])
 821             return (af);
 822
 823     return (!af);
 824 }
 825
 826
 827 static int
 828 tcompile (char *ap, struct tws *tb, int isafter)
 829 {
 830     struct tws *tw;
 831
 832     if ((tw = tws_parse (ap, isafter)) == NULL)
 833         return 0;
 834
 835     *tb = *tw;
 836     return 1;
 837 }
 838
 839
 840 static struct tws *
 841 tws_parse (char *ap, int isafter)
 842 {
 843     char buffer[BUFSIZ];
 844     struct tws *tw, *ts;
 845
 846     if ((tw = tws_special (ap)) != NULL) {
 847         tw->tw_sec = tw->tw_min = isafter ? 59 : 0;
 848         tw->tw_hour = isafter ? 23 : 0;
 849         return tw;
 850     }
 851     if ((tw = dparsetime (ap)) != NULL)
 852         return tw;
 853
 854     if ((ts = dlocaltimenow ()) == NULL)
 855         return NULL;
 856
 857     snprintf (buffer, sizeof(buffer), "%s %s", ap, dtwszone (ts));
 858     if ((tw = dparsetime (buffer)) != NULL)
 859         return tw;
 860
 861     snprintf (buffer, sizeof(buffer), "%s %02d:%02d:%02d %s", ap,
 862             ts->tw_hour, ts->tw_min, ts->tw_sec, dtwszone (ts));
 863     if ((tw = dparsetime (buffer)) != NULL)
 864         return tw;
 865
 866     snprintf (buffer, sizeof(buffer), "%02d %s %04d %s",
 867             ts->tw_mday, tw_moty[ts->tw_mon], ts->tw_year, ap);
 868     if ((tw = dparsetime (buffer)) != NULL)
 869         return tw;
 870
 871     snprintf (buffer, sizeof(buffer), "%02d %s %04d %s %s",
 872             ts->tw_mday, tw_moty[ts->tw_mon], ts->tw_year,
 873             ap, dtwszone (ts));
 874     if ((tw = dparsetime (buffer)) != NULL)
 875         return tw;
 876
 877     return NULL;
 878 }
 879
 880
 881 static struct tws *
 882 tws_special (char *ap)
 883 {
 884     int i;
 885     time_t clock;
 886     struct tws *tw;
 887
 888     time (&clock);
 889     if (!strcasecmp (ap, "today"))
 890         return dlocaltime (&clock);
 891     if (!strcasecmp (ap, "yesterday")) {
 892         clock -= (long) (60 * 60 * 24);
 893         return dlocaltime (&clock);
 894     }
 895     if (!strcasecmp (ap, "tomorrow")) {
 896         clock += (long) (60 * 60 * 24);
 897         return dlocaltime (&clock);
 898     }
 899
 900     for (i = 0; tw_ldotw[i]; i++)
 901         if (!strcasecmp (ap, tw_ldotw[i]))
 902             break;
 903     if (tw_ldotw[i]) {
 904         if ((tw = dlocaltime (&clock)) == NULL)
 905             return NULL;
 906         if ((i -= tw->tw_wday) > 0)
 907             i -= 7;
 908     }
 909     else {
 910         if (*ap != '-')
 911             return NULL;
 912         /* -ddd days ago */
 913         i = atoi (ap);  /* we should error check this */
 914     }
 915
 916     clock += (long) ((60 * 60 * 24) * i);
 917     return dlocaltime (&clock);
 918 }
 919
 920
 921 static int
 922 TWSaction(struct nexus *n, FILE *fp, int msgnum, long start, long stop)
 923 {
 924     int state;
 925     char *bp;
 926     char buf[NMH_BUFSIZ], name[NAMESZ];
 927     struct tws *tw;
 928     m_getfld_state_t gstate = 0;
 929     NMH_UNUSED (stop);
 930
 931     fseek (fp, start, SEEK_SET);
 932     for (bp = NULL;;) {
 933         int bufsz = sizeof buf;
 934         switch (state = m_getfld (&gstate, name, buf, &bufsz, fp)) {
 935             case FLD:
 936             case FLDPLUS:
 937                 mh_xfree(bp);
 938                 bp = mh_xstrdup(buf);
 939                 while (state == FLDPLUS) {
 940                     bufsz = sizeof buf;
 941                     state = m_getfld (&gstate, name, buf, &bufsz, fp);
 942                     bp = add (buf, bp);
 943                 }
 944                 if (!strcasecmp (name, n->n_datef))
 945                     break;
 946                 continue;
 947
 948             case BODY:
 949             case FILEEOF:
 950             case LENERR:
 951             case FMTERR:
 952                 if (state == LENERR || state == FMTERR)
 953                     inform("format error in message %d", msgnum);
 954                 mh_xfree(bp);
 955                 return 0;
 956
 957             default:
 958                 adios (NULL, "internal error -- you lose");
 959         }
 960         break;
 961     }
 962     m_getfld_state_destroy (&gstate);
 963
 964     if ((tw = dparsetime (bp)) == NULL)
 965         inform("unable to parse %s field in message %d, matching...",
 966                 n->n_datef, msgnum), state = 1;
 967     else
 968         state = n->n_after ? (twsort (tw, &n->n_tws) > 0)
 969             : (twsort (tw, &n->n_tws) < 0);
 970
 971     mh_xfree(bp);
 972     return state;
 973 }