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 (*)());
 184
 185 static int ORaction();
 186 static int ANDaction();
 187 static int NOTaction();
 188 static int GREPaction();
 189 static int TWSaction();
 190
 191
 192 int
 193 pcompile (char **vec, char *date)
 194 {
 195     argp = vec;
 196     if ((datesw = date) == NULL)
 197         datesw = "date";
 198     talked = 0;
 199
 200     if ((head = parse ()) == NULL)
 201         return (talked ? 0 : 1);
 202
 203     if (*argp) {
 204         inform("%s unexpected", *argp);
 205         return 0;
 206     }
 207
 208     return 1;
 209 }
 210
 211
 212 static struct nexus *
 213 parse (void)
 214 {
 215     char  *cp;
 216     struct nexus *n, *o;
 217
 218     if ((n = nexp1 ()) == NULL || (cp = nxtarg ()) == NULL)
 219         return n;
 220
 221     if (*cp != '-') {
 222         pinform("%s unexpected", cp);
 223         return NULL;
 224     }
 225
 226     if (*++cp == '-')
 227         goto header;
 228     switch (smatch (cp, parswit)) {
 229         case AMBIGSW:
 230             ambigsw (cp, parswit);
 231             talked++;
 232             return NULL;
 233         case UNKWNSW:
 234             fprintf (stderr, "-%s unknown\n", cp);
 235             talked++;
 236             return NULL;
 237
 238         case PROR:
 239             o = newnexus (ORaction);
 240             o->n_L_child = n;
 241             if ((o->n_R_child = parse ()))
 242                 return o;
 243             pinform("missing disjunctive");
 244             free (o);
 245             return NULL;
 246
 247 header: ;
 248         default:
 249             prvarg ();
 250             return n;
 251     }
 252 }
 253
 254 static struct nexus *
 255 nexp1 (void)
 256 {
 257     char *cp;
 258     struct nexus *n, *o;
 259
 260     if ((n = nexp2 ()) == NULL || (cp = nxtarg ()) == NULL)
 261         return n;
 262
 263     if (*cp != '-') {
 264         pinform("%s unexpected", cp);
 265         free (n);
 266         return NULL;
 267     }
 268
 269     if (*++cp == '-')
 270         goto header;
 271     switch (smatch (cp, parswit)) {
 272         case AMBIGSW:
 273             ambigsw (cp, parswit);
 274             talked++;
 275             free (n);
 276             return NULL;
 277         case UNKWNSW:
 278             fprintf (stderr, "-%s unknown\n", cp);
 279             talked++;
 280             free (n);
 281             return NULL;
 282
 283         case PRAND:
 284             o = newnexus (ANDaction);
 285             o->n_L_child = n;
 286             if ((o->n_R_child = nexp1 ()))
 287                 return o;
 288             pinform("missing conjunctive");
 289             free (o);
 290             return NULL;
 291
 292 header: ;
 293         default:
 294             prvarg ();
 295             return n;
 296     }
 297 }
 298
 299
 300 static struct nexus *
 301 nexp2 (void)
 302 {
 303     char *cp;
 304     struct nexus *n;
 305
 306     if ((cp = nxtarg ()) == NULL)
 307         return NULL;
 308
 309     if (*cp != '-') {
 310         prvarg ();
 311         return nexp3 ();
 312     }
 313
 314     if (*++cp == '-')
 315         goto header;
 316     switch (smatch (cp, parswit)) {
 317         case AMBIGSW:
 318             ambigsw (cp, parswit);
 319             talked++;
 320             return NULL;
 321         case UNKWNSW:
 322             fprintf (stderr, "-%s unknown\n", cp);
 323             talked++;
 324             return NULL;
 325
 326         case PRNOT:
 327             n = newnexus (NOTaction);
 328             if ((n->n_L_child = nexp3 ()))
 329                 return n;
 330             pinform("missing negation");
 331             free (n);
 332             return NULL;
 333
 334 header: ;
 335         default:
 336             prvarg ();
 337             return nexp3 ();
 338     }
 339 }
 340
 341 static struct nexus *
 342 nexp3 (void)
 343 {
 344     int i;
 345     char *cp, *dp;
 346     char buffer[BUFSIZ], temp[64];
 347     struct nexus *n;
 348
 349     if ((cp = nxtarg ()) == NULL)
 350         return NULL;
 351
 352     if (*cp != '-') {
 353         pinform("%s unexpected", cp);
 354         return NULL;
 355     }
 356
 357     if (*++cp == '-') {
 358         dp = ++cp;
 359         goto header;
 360     }
 361     switch (i = smatch (cp, parswit)) {
 362         case AMBIGSW:
 363             ambigsw (cp, parswit);
 364             talked++;
 365             return NULL;
 366         case UNKWNSW:
 367             fprintf (stderr, "-%s unknown\n", cp);
 368             talked++;
 369             return NULL;
 370
 371         case PRLBR:
 372             if ((n = parse ()) == NULL) {
 373                 pinform("missing group");
 374                 return NULL;
 375             }
 376             if ((cp = nxtarg ()) == NULL) {
 377                 pinform("missing -rbrace");
 378                 return NULL;
 379             }
 380             if (*cp++ == '-' && smatch (cp, parswit) == PRRBR)
 381                 return n;
 382             pinform("%s unexpected", --cp);
 383             return NULL;
 384
 385         default:
 386             prvarg ();
 387             return NULL;
 388
 389         case PRCC:
 390         case PRDATE:
 391         case PRFROM:
 392         case PRTO:
 393         case PRSUBJ:
 394             strncpy(temp, parswit[i].sw, sizeof(temp));
 395             temp[sizeof(temp) - 1] = '\0';
 396             dp = *brkstring (temp, " ", NULL);
 397     header: ;
 398             if (!(cp = nxtarg ())) {/* allow -xyz arguments */
 399                 pinform("missing argument to %s", argp[-2]);
 400                 return NULL;
 401             }
 402             n = newnexus (GREPaction);
 403             n->n_header = 1;
 404             snprintf (buffer, sizeof(buffer), "^%s[ \t]*:.*%s", dp, cp);
 405             dp = buffer;
 406             goto pattern;
 407
 408         case PRSRCH:
 409             n = newnexus (GREPaction);
 410             n->n_header = 0;
 411             if (!(cp = nxtarg ())) {/* allow -xyz arguments */
 412                 pinform("missing argument to %s", argp[-2]);
 413                 free (n);
 414                 return NULL;
 415             }
 416             dp = cp;
 417     pattern: ;
 418             if (!gcompile (n, dp)) {
 419                 pinform("pattern error in %s %s", argp[-2], cp);
 420                 free (n);
 421                 return NULL;
 422             }
 423             n->n_patbuf = mh_xstrdup(dp);
 424             return n;
 425
 426         case PROTHR:
 427             pinform("internal error!");
 428             return NULL;
 429
 430         case PRDATF:
 431             if (!(datesw = nxtarg ()) || *datesw == '-') {
 432                 pinform("missing argument to %s", argp[-2]);
 433                 return NULL;
 434             }
 435             return nexp3 ();
 436
 437         case PRAFTR:
 438         case PRBEFR:
 439             if (!(cp = nxtarg ())) {/* allow -xyz arguments */
 440                 pinform("missing argument to %s", argp[-2]);
 441                 return NULL;
 442             }
 443             n = newnexus (TWSaction);
 444             n->n_datef = datesw;
 445             if (!tcompile (cp, &n->n_tws, n->n_after = i == PRAFTR)) {
 446                 pinform("unable to parse %s %s", argp[-2], cp);
 447                 free (n);
 448                 return NULL;
 449             }
 450             return n;
 451     }
 452 }
 453
 454
 455 static struct nexus *
 456 newnexus (int (*action)())
 457 {
 458     struct nexus *p;
 459
 460     NEW0(p);
 461     p->n_action = action;
 462     return p;
 463 }
 464
 465
 466 #define args(a) a, fp, msgnum, start, stop
 467 #define params  args (n)
 468 #define plist   \
 469             struct nexus  *n; \
 470             FILE *fp; \
 471             int msgnum; \
 472             long    start, \
 473                     stop;
 474
 475 int
 476 pmatches (FILE *fp, int msgnum, long start, long stop, int debug)
 477 {
 478     if (!head)
 479         return 1;
 480
 481     if (!talked++ && debug)
 482         PRaction (head, 0);
 483
 484     return (*head->n_action) (args (head));
 485 }
 486
 487
 488 static void
 489 PRaction (struct nexus *n, int level)
 490 {
 491     int i;
 492
 493     for (i = 0; i < level; i++)
 494         fprintf (stderr, "| ");
 495
 496     if (n->n_action == ORaction) {
 497         fprintf (stderr, "OR\n");
 498         PRaction (n->n_L_child, level + 1);
 499         PRaction (n->n_R_child, level + 1);
 500         return;
 501     }
 502     if (n->n_action == ANDaction) {
 503         fprintf (stderr, "AND\n");
 504         PRaction (n->n_L_child, level + 1);
 505         PRaction (n->n_R_child, level + 1);
 506         return;
 507     }
 508     if (n->n_action == NOTaction) {
 509         fprintf (stderr, "NOT\n");
 510         PRaction (n->n_L_child, level + 1);
 511         return;
 512     }
 513     if (n->n_action == GREPaction) {
 514         fprintf (stderr, "PATTERN(%s) %s\n",
 515                 n->n_header ? "header" : "body", n->n_patbuf);
 516         return;
 517     }
 518     if (n->n_action == TWSaction) {
 519         fprintf (stderr, "TEMPORAL(%s) %s: %s\n",
 520                 n->n_after ? "after" : "before", n->n_datef,
 521                 dasctime (&n->n_tws, TW_NULL));
 522         return;
 523     }
 524     fprintf (stderr, "UNKNOWN(0x%x)\n",
 525              (unsigned int)(unsigned long) (*n->n_action));
 526 }
 527
 528
 529 static int
 530 ORaction (params)
 531 plist
 532 {
 533     if ((*n->n_L_child->n_action) (args (n->n_L_child)))
 534         return 1;
 535     return (*n->n_R_child->n_action) (args (n->n_R_child));
 536 }
 537
 538
 539 static int
 540 ANDaction (params)
 541 plist
 542 {
 543     if (!(*n->n_L_child->n_action) (args (n->n_L_child)))
 544         return 0;
 545     return (*n->n_R_child->n_action) (args (n->n_R_child));
 546 }
 547
 548
 549 static int
 550 NOTaction (params)
 551 plist
 552 {
 553     return (!(*n->n_L_child->n_action) (args (n->n_L_child)));
 554 }
 555
 556
 557 static int
 558 gcompile (struct nexus *n, char *astr)
 559 {
 560     int c;
 561     int cclcnt;
 562     unsigned char *ep, *dp, *sp, *lastep = 0;
 563
 564     dp = (ep = (unsigned char *) n->n_expbuf) + sizeof n->n_expbuf;
 565     sp = (unsigned char *) astr;
 566     if (*sp == '^') {
 567         n->n_circf = 1;
 568         sp++;
 569     }
 570     else
 571         n->n_circf = 0;
 572     for (;;) {
 573         if (ep >= dp)
 574             goto cerror;
 575         if ((c = *sp++) != '*')
 576             lastep = ep;
 577         switch (c) {
 578             case '\0':
 579                 *ep++ = CEOF;
 580                 return 1;
 581
 582             case '.':
 583                 *ep++ = CDOT;
 584                 continue;
 585
 586             case '*':
 587                 if (lastep == 0)
 588                     goto defchar;
 589                 *lastep |= STAR;
 590                 continue;
 591
 592             case '$':
 593                 if (*sp != '\0')
 594                     goto defchar;
 595                 *ep++ = CDOL;
 596                 continue;
 597
 598             case '[':
 599                 *ep++ = CCL;
 600                 *ep++ = 0;
 601                 cclcnt = 0;
 602                 if ((c = *sp++) == '^') {
 603                     c = *sp++;
 604                     ep[-2] = NCCL;
 605                 }
 606                 if (c == '-') {
 607                     *ep++ = c;
 608                     cclcnt++;
 609                     c = *sp++;
 610                 }
 611                 do {
 612                     if (c == '-' && *sp != '\0' && *sp != ']') {
 613                         for (c = ep[-1]+1; c < *sp; c++) {
 614                             *ep++ = c;
 615                             cclcnt++;
 616                             if (c == '\0' || ep >= dp)
 617                                 goto cerror;
 618                         }
 619                     } else {
 620                         *ep++ = c;
 621                         cclcnt++;
 622                         if (c == '\0' || ep >= dp)
 623                             goto cerror;
 624                     }
 625                 } while ((c = *sp++) != ']');
 626                 if (cclcnt > 255)
 627                     goto cerror;
 628                 lastep[1] = cclcnt;
 629                 continue;
 630
 631             case '\\':
 632                 if ((c = *sp++) == '\0')
 633                     goto cerror;
 634                 /* FALLTHRU */
 635         defchar:
 636             default:
 637                 *ep++ = CCHR;
 638                 *ep++ = c;
 639         }
 640     }
 641
 642 cerror: ;
 643     return 0;
 644 }
 645
 646
 647 static int
 648 GREPaction (params)
 649 plist
 650 {
 651     int c, body, lf;
 652     long pos = start;
 653     char *p1, *p2, *ebp, *cbp;
 654     char ibuf[BUFSIZ];
 655     NMH_UNUSED (msgnum);
 656
 657     fseek (fp, start, SEEK_SET);
 658     body = 0;
 659     ebp = cbp = ibuf;
 660     for (;;) {
 661         if (body && n->n_header)
 662             return 0;
 663         p1 = linebuf;
 664         p2 = cbp;
 665         lf = 0;
 666         for (;;) {
 667             if (p2 >= ebp) {
 668                 if (fgets (ibuf, sizeof ibuf, fp) == NULL
 669                         || (stop && pos >= stop)) {
 670                     if (lf)
 671                         break;
 672                     return 0;
 673                 }
 674                 pos += (long) strlen (ibuf);
 675                 p2 = ibuf;
 676                 ebp = ibuf + strlen (ibuf);
 677             }
 678             c = *p2++;
 679             if (lf && c != '\n') {
 680                 if (c != ' ' && c != '\t') {
 681                     --p2;
 682                     break;
 683                 }
 684                 lf = 0;
 685             }
 686             if (c == '\n') {
 687                 if (body)
 688                     break;
 689                 if (lf) {
 690                     body++;
 691                     break;
 692                 }
 693                 lf++;
 694                 /* Unfold by skipping the newline. */
 695                 c = 0;
 696             }
 697             if (c && p1 < &linebuf[LBSIZE - 1])
 698                 *p1++ = c;
 699         }
 700
 701         *p1++ = 0;
 702         cbp = p2;
 703         p1 = linebuf;
 704         p2 = n->n_expbuf;
 705
 706         /* Attempt to decode as a MIME header.  If it's the last header,
 707            body will be 1 and lf will be at least 1. */
 708         if ((body == 0 || lf > 0)  &&
 709             decode_rfc2047 (linebuf, decoded_linebuf, sizeof decoded_linebuf)) {
 710             p1 = decoded_linebuf;
 711         }
 712
 713         if (n->n_circf) {
 714             if (advance (p1, p2))
 715                 return 1;
 716             continue;
 717         }
 718
 719         if (*p2 == CCHR) {
 720             c = p2[1];
 721             do {
 722                 if (*p1 == c || cc[(unsigned char)*p1] == c)
 723                     if (advance (p1, p2))
 724                         return 1;
 725             } while (*p1++);
 726             continue;
 727         }
 728
 729         do {
 730             if (advance (p1, p2))
 731                 return 1;
 732         } while (*p1++);
 733     }
 734 }
 735
 736
 737 static int
 738 advance (char *alp, char *aep)
 739 {
 740     unsigned char *lp, *ep, *curlp;
 741
 742     lp = (unsigned char *)alp;
 743     ep = (unsigned char *)aep;
 744     for (;;)
 745         switch (*ep++) {
 746             case CCHR:
 747                 if (*ep++ == *lp++ || ep[-1] == cc[lp[-1]])
 748                     continue;
 749                 return 0;
 750
 751             case CDOT:
 752                 if (*lp++)
 753                     continue;
 754                 return 0;
 755
 756             case CDOL:
 757                 if (*lp == 0)
 758                     continue;
 759                 return 0;
 760
 761             case CEOF:
 762                 return 1;
 763
 764             case CCL:
 765                 if (cclass (ep, *lp++, 1)) {
 766                     ep += *ep + 1;
 767                     continue;
 768                 }
 769                 return 0;
 770
 771             case NCCL:
 772                 if (cclass (ep, *lp++, 0)) {
 773                     ep += *ep + 1;
 774                     continue;
 775                 }
 776                 return 0;
 777
 778             case CDOT | STAR:
 779                 curlp = lp;
 780                 while (*lp++)
 781                     continue;
 782                 goto star;
 783
 784             case CCHR | STAR:
 785                 curlp = lp;
 786                 while (*lp++ == *ep || cc[lp[-1]] == *ep)
 787                     continue;
 788                 ep++;
 789                 goto star;
 790
 791             case CCL | STAR:
 792             case NCCL | STAR:
 793                 curlp = lp;
 794                 while (cclass (ep, *lp++, ep[-1] == (CCL | STAR)))
 795                     continue;
 796                 ep += *ep + 1;
 797                 goto star;
 798
 799         star:
 800                 do {
 801                     lp--;
 802                     if (advance ((char *) lp, (char *) ep))
 803                         return (1);
 804                 } while (lp > curlp);
 805                 return 0;
 806
 807             default:
 808                 inform("advance() botch -- you lose big, continuing...");
 809                 return 0;
 810         }
 811 }
 812
 813
 814 static int
 815 cclass (unsigned char *aset, int ac, int af)
 816 {
 817     unsigned int    n;
 818     unsigned char   c, *set;
 819
 820     set = aset;
 821     if ((c = ac) == 0)
 822         return (0);
 823
 824     n = *set++;
 825     while (n--)
 826         if (*set++ == c || set[-1] == cc[c])
 827             return (af);
 828
 829     return (!af);
 830 }
 831
 832
 833 static int
 834 tcompile (char *ap, struct tws *tb, int isafter)
 835 {
 836     struct tws *tw;
 837
 838     if ((tw = tws_parse (ap, isafter)) == NULL)
 839         return 0;
 840
 841     *tb = *tw;
 842     return 1;
 843 }
 844
 845
 846 static struct tws *
 847 tws_parse (char *ap, int isafter)
 848 {
 849     char buffer[BUFSIZ];
 850     struct tws *tw, *ts;
 851
 852     if ((tw = tws_special (ap)) != NULL) {
 853         tw->tw_sec = tw->tw_min = isafter ? 59 : 0;
 854         tw->tw_hour = isafter ? 23 : 0;
 855         return tw;
 856     }
 857     if ((tw = dparsetime (ap)) != NULL)
 858         return tw;
 859
 860     if ((ts = dlocaltimenow ()) == NULL)
 861         return NULL;
 862
 863     snprintf (buffer, sizeof(buffer), "%s %s", ap, dtwszone (ts));
 864     if ((tw = dparsetime (buffer)) != NULL)
 865         return tw;
 866
 867     snprintf (buffer, sizeof(buffer), "%s %02d:%02d:%02d %s", ap,
 868             ts->tw_hour, ts->tw_min, ts->tw_sec, dtwszone (ts));
 869     if ((tw = dparsetime (buffer)) != NULL)
 870         return tw;
 871
 872     snprintf (buffer, sizeof(buffer), "%02d %s %04d %s",
 873             ts->tw_mday, tw_moty[ts->tw_mon], ts->tw_year, ap);
 874     if ((tw = dparsetime (buffer)) != NULL)
 875         return tw;
 876
 877     snprintf (buffer, sizeof(buffer), "%02d %s %04d %s %s",
 878             ts->tw_mday, tw_moty[ts->tw_mon], ts->tw_year,
 879             ap, dtwszone (ts));
 880     if ((tw = dparsetime (buffer)) != NULL)
 881         return tw;
 882
 883     return NULL;
 884 }
 885
 886
 887 static struct tws *
 888 tws_special (char *ap)
 889 {
 890     int i;
 891     time_t clock;
 892     struct tws *tw;
 893
 894     time (&clock);
 895     if (!strcasecmp (ap, "today"))
 896         return dlocaltime (&clock);
 897     if (!strcasecmp (ap, "yesterday")) {
 898         clock -= (long) (60 * 60 * 24);
 899         return dlocaltime (&clock);
 900     }
 901     if (!strcasecmp (ap, "tomorrow")) {
 902         clock += (long) (60 * 60 * 24);
 903         return dlocaltime (&clock);
 904     }
 905
 906     for (i = 0; tw_ldotw[i]; i++)
 907         if (!strcasecmp (ap, tw_ldotw[i]))
 908             break;
 909     if (tw_ldotw[i]) {
 910         if ((tw = dlocaltime (&clock)) == NULL)
 911             return NULL;
 912         if ((i -= tw->tw_wday) > 0)
 913             i -= 7;
 914     }
 915     else {
 916         if (*ap != '-')
 917             return NULL;
 918         /* -ddd days ago */
 919         i = atoi (ap);  /* we should error check this */
 920     }
 921
 922     clock += (long) ((60 * 60 * 24) * i);
 923     return dlocaltime (&clock);
 924 }
 925
 926
 927 static int
 928 TWSaction (params)
 929 plist
 930 {
 931     int state;
 932     char *bp;
 933     char buf[NMH_BUFSIZ], name[NAMESZ];
 934     struct tws *tw;
 935     m_getfld_state_t gstate = 0;
 936     NMH_UNUSED (stop);
 937
 938     fseek (fp, start, SEEK_SET);
 939     for (bp = NULL;;) {
 940         int bufsz = sizeof buf;
 941         switch (state = m_getfld (&gstate, name, buf, &bufsz, fp)) {
 942             case FLD:
 943             case FLDPLUS:
 944                 mh_xfree(bp);
 945                 bp = mh_xstrdup(buf);
 946                 while (state == FLDPLUS) {
 947                     bufsz = sizeof buf;
 948                     state = m_getfld (&gstate, name, buf, &bufsz, fp);
 949                     bp = add (buf, bp);
 950                 }
 951                 if (!strcasecmp (name, n->n_datef))
 952                     break;
 953                 continue;
 954
 955             case BODY:
 956             case FILEEOF:
 957             case LENERR:
 958             case FMTERR:
 959                 if (state == LENERR || state == FMTERR)
 960                     inform("format error in message %d", msgnum);
 961                 mh_xfree(bp);
 962                 return 0;
 963
 964             default:
 965                 adios (NULL, "internal error -- you lose");
 966         }
 967         break;
 968     }
 969     m_getfld_state_destroy (&gstate);
 970
 971     if ((tw = dparsetime (bp)) == NULL)
 972         inform("unable to parse %s field in message %d, matching...",
 973                 n->n_datef, msgnum), state = 1;
 974     else
 975         state = n->n_after ? (twsort (tw, &n->n_tws) > 0)
 976             : (twsort (tw, &n->n_tws) < 0);
 977
 978     mh_xfree(bp);
 979     return state;
 980 }