tests2/46_grep.c

   1 /*
   2  * The  information  in  this  document  is  subject  to  change
   3  * without  notice  and  should not be construed as a commitment
   4  * by Digital Equipment Corporation or by DECUS.
   5  *
   6  * Neither Digital Equipment Corporation, DECUS, nor the authors
   7  * assume any responsibility for the use or reliability of  this
   8  * document or the described software.
   9  *
  10  *      Copyright (C) 1980, DECUS
  11  *
  12  * General permission to copy or modify, but not for profit,  is
  13  * hereby  granted,  provided that the above copyright notice is
  14  * included and reference made to  the  fact  that  reproduction
  15  * privileges were granted by DECUS.
  16  */
  17 #include <stdio.h>
  18
  19 /*
  20  * grep
  21  *
  22  * Runs on the Decus compiler or on vms, On vms, define as:
  23  *      grep :== "$disk:[account]grep"      (native)
  24  *      grep :== "$disk:[account]grep grep" (Decus)
  25  * See below for more information.
  26  */
  27
  28 #if 0
  29 char    *documentation[] = {
  30    "grep searches a file for a given pattern.  Execute by",
  31    "   grep [flags] regular_expression file_list\n",
  32    "Flags are single characters preceeded by '-':",
  33    "   -c      Only a count of matching lines is printed",
  34    "   -f      Print file name for matching lines switch, see below",
  35    "   -n      Each line is preceeded by its line number",
  36    "   -v      Only print non-matching lines\n",
  37    "The file_list is a list of files (wildcards are acceptable on RSX modes).",
  38    "\nThe file name is normally printed if there is a file given.",
  39    "The -f flag reverses this action (print name no file, not if more).\n",
  40    0 };
  41
  42 char    *patdoc[] = {
  43    "The regular_expression defines the pattern to search for.  Upper- and",
  44    "lower-case are always ignored.  Blank lines never match.  The expression",
  45    "should be quoted to prevent file-name translation.",
  46    "x      An ordinary character (not mentioned below) matches that character.",
  47    "'\\'    The backslash quotes any character.  \"\\$\" matches a dollar-sign.",
  48    "'^'    A circumflex at the beginning of an expression matches the",
  49    "       beginning of a line.",
  50    "'$'    A dollar-sign at the end of an expression matches the end of a line.",
  51    "'.'    A period matches any character except \"new-line\".",
  52    "':a'   A colon matches a class of characters described by the following",
  53    "':d'     character.  \":a\" matches any alphabetic, \":d\" matches digits,",
  54    "':n'     \":n\" matches alphanumerics, \": \" matches spaces, tabs, and",
  55    "': '     other control characters, such as new-line.",
  56    "'*'    An expression followed by an asterisk matches zero or more",
  57    "       occurrances of that expression: \"fo*\" matches \"f\", \"fo\"",
  58    "       \"foo\", etc.",
  59    "'+'    An expression followed by a plus sign matches one or more",
  60    "       occurrances of that expression: \"fo+\" matches \"fo\", etc.",
  61    "'-'    An expression followed by a minus sign optionally matches",
  62    "       the expression.",
  63    "'[]'   A string enclosed in square brackets matches any character in",
  64    "       that string, but no others.  If the first character in the",
  65    "       string is a circumflex, the expression matches any character",
  66    "       except \"new-line\" and the characters in the string.  For",
  67    "       example, \"[xyz]\" matches \"xx\" and \"zyx\", while \"[^xyz]\"",
  68    "       matches \"abc\" but not \"axb\".  A range of characters may be",
  69    "       specified by two characters separated by \"-\".  Note that,",
  70    "       [a-z] matches alphabetics, while [z-a] never matches.",
  71    "The concatenation of regular expressions is a regular expression.",
  72    0};
  73 #endif
  74
  75 #define LMAX    512
  76 #define PMAX    256
  77
  78 #define CHAR    1
  79 #define BOL     2
  80 #define EOL     3
  81 #define ANY     4
  82 #define CLASS   5
  83 #define NCLASS  6
  84 #define STAR    7
  85 #define PLUS    8
  86 #define MINUS   9
  87 #define ALPHA   10
  88 #define DIGIT   11
  89 #define NALPHA  12
  90 #define PUNCT   13
  91 #define RANGE   14
  92 #define ENDPAT  15
  93
  94 int cflag=0, fflag=0, nflag=0, vflag=0, nfile=0, debug=0;
  95
  96 char *pp, lbuf[LMAX], pbuf[PMAX];
  97
  98 char *cclass();
  99 char *pmatch();
 100
 101
 102 /*** Display a file name *******************************/
 103 void file(char *s)
 104 {
 105    printf("File %s:\n", s);
 106 }
 107
 108 /*** Report unopenable file ****************************/
 109 void cant(char *s)
 110 {
 111    fprintf(stderr, "%s: cannot open\n", s);
 112 }
 113
 114 /*** Give good help ************************************/
 115 void help(char **hp)
 116 {
 117    char   **dp;
 118
 119    for (dp = hp; *dp; ++dp)
 120       printf("%s\n", *dp);
 121 }
 122
 123 /*** Display usage summary *****************************/
 124 void usage(char *s)
 125 {
 126    fprintf(stderr, "?GREP-E-%s\n", s);
 127    fprintf(stderr,
 128          "Usage: grep [-cfnv] pattern [file ...].  grep ? for help\n");
 129    exit(1);
 130 }
 131
 132 /*** Compile the pattern into global pbuf[] ************/
 133 void compile(char *source)
 134 {
 135    char  *s;         /* Source string pointer     */
 136    char  *lp;        /* Last pattern pointer      */
 137    int   c;          /* Current character         */
 138    int            o;          /* Temp                      */
 139    char           *spp;       /* Save beginning of pattern */
 140
 141    s = source;
 142    if (debug)
 143       printf("Pattern = \"%s\"\n", s);
 144    pp = pbuf;
 145    while (c = *s++) {
 146       /*
 147        * STAR, PLUS and MINUS are special.
 148        */
 149       if (c == '*' || c == '+' || c == '-') {
 150          if (pp == pbuf ||
 151                (o=pp[-1]) == BOL ||
 152                o == EOL ||
 153                o == STAR ||
 154                o == PLUS ||
 155                o == MINUS)
 156             badpat("Illegal occurrance op.", source, s);
 157          store(ENDPAT);
 158          store(ENDPAT);
 159          spp = pp;               /* Save pattern end     */
 160          while (--pp > lp)       /* Move pattern down    */
 161             *pp = pp[-1];        /* one byte             */
 162          *pp =   (c == '*') ? STAR :
 163             (c == '-') ? MINUS : PLUS;
 164          pp = spp;               /* Restore pattern end  */
 165          continue;
 166       }
 167       /*
 168        * All the rest.
 169        */
 170       lp = pp;         /* Remember start       */
 171       switch(c) {
 172
 173          case '^':
 174             store(BOL);
 175             break;
 176
 177          case '$':
 178             store(EOL);
 179             break;
 180
 181          case '.':
 182             store(ANY);
 183             break;
 184
 185          case '[':
 186             s = cclass(source, s);
 187             break;
 188
 189          case ':':
 190             if (*s) {
 191                switch(tolower(c = *s++)) {
 192
 193                   case 'a':
 194                   case 'A':
 195                      store(ALPHA);
 196                      break;
 197
 198                   case 'd':
 199                   case 'D':
 200                      store(DIGIT);
 201                      break;
 202
 203                   case 'n':
 204                   case 'N':
 205                      store(NALPHA);
 206                      break;
 207
 208                   case ' ':
 209                      store(PUNCT);
 210                      break;
 211
 212                   default:
 213                      badpat("Unknown : type", source, s);
 214
 215                }
 216                break;
 217             }
 218             else    badpat("No : type", source, s);
 219
 220          case '\\':
 221             if (*s)
 222                c = *s++;
 223
 224          default:
 225             store(CHAR);
 226             store(tolower(c));
 227       }
 228    }
 229    store(ENDPAT);
 230    store(0);                /* Terminate string     */
 231    if (debug) {
 232       for (lp = pbuf; lp < pp;) {
 233          if ((c = (*lp++ & 0377)) < ' ')
 234             printf("\\%o ", c);
 235          else    printf("%c ", c);
 236       }
 237       printf("\n");
 238    }
 239 }
 240
 241 /*** Compile a class (within []) ***********************/
 242 char *cclass(char *source, char *src)
 243    /* char       *source;   // Pattern start -- for error msg. */
 244    /* char       *src;      // Class start */
 245 {
 246    char   *s;        /* Source pointer    */
 247    char   *cp;       /* Pattern start     */
 248    int    c;         /* Current character */
 249    int             o;         /* Temp              */
 250
 251    s = src;
 252    o = CLASS;
 253    if (*s == '^') {
 254       ++s;
 255       o = NCLASS;
 256    }
 257    store(o);
 258    cp = pp;
 259    store(0);                          /* Byte count      */
 260    while ((c = *s++) && c!=']') {
 261       if (c == '\\') {                /* Store quoted char    */
 262          if ((c = *s++) == '\0')      /* Gotta get something  */
 263             badpat("Class terminates badly", source, s);
 264          else    store(tolower(c));
 265       }
 266       else if (c == '-' &&
 267             (pp - cp) > 1 && *s != ']' && *s != '\0') {
 268          c = pp[-1];             /* Range start     */
 269          pp[-1] = RANGE;         /* Range signal    */
 270          store(c);               /* Re-store start  */
 271          c = *s++;               /* Get end char and*/
 272          store(tolower(c));      /* Store it        */
 273       }
 274       else {
 275          store(tolower(c));      /* Store normal char */
 276       }
 277    }
 278    if (c != ']')
 279       badpat("Unterminated class", source, s);
 280    if ((c = (pp - cp)) >= 256)
 281       badpat("Class too large", source, s);
 282    if (c == 0)
 283       badpat("Empty class", source, s);
 284    *cp = c;
 285    return(s);
 286 }
 287
 288 /*** Store an entry in the pattern buffer **************/
 289 void store(int op)
 290 {
 291    if (pp >= &pbuf[PMAX])
 292       error("Pattern too complex\n");
 293    *pp++ = op;
 294 }
 295
 296 /*** Report a bad pattern specification ****************/
 297 void badpat(char *message, char *source, char *stop)
 298    /* char  *message;       // Error message */
 299    /* char  *source;        // Pattern start */
 300    /* char  *stop;          // Pattern end   */
 301 {
 302    fprintf(stderr, "-GREP-E-%s, pattern is\"%s\"\n", message, source);
 303    fprintf(stderr, "-GREP-E-Stopped at byte %d, '%c'\n",
 304          stop-source, stop[-1]);
 305    error("?GREP-E-Bad pattern\n");
 306 }
 307
 308 /*** Scan the file for the pattern in pbuf[] ***********/
 309 void grep(FILE *fp, char *fn)
 310    /* FILE       *fp;       // File to process            */
 311    /* char       *fn;       // File name (for -f option)  */
 312 {
 313    int lno, count, m;
 314
 315    lno = 0;
 316    count = 0;
 317    while (fgets(lbuf, LMAX, fp)) {
 318       ++lno;
 319       m = match();
 320       if ((m && !vflag) || (!m && vflag)) {
 321          ++count;
 322          if (!cflag) {
 323             if (fflag && fn) {
 324                file(fn);
 325                fn = 0;
 326             }
 327             if (nflag)
 328                printf("%d\t", lno);
 329             printf("%s\n", lbuf);
 330          }
 331       }
 332    }
 333    if (cflag) {
 334       if (fflag && fn)
 335          file(fn);
 336       printf("%d\n", count);
 337    }
 338 }
 339
 340 /*** Match line (lbuf) with pattern (pbuf) return 1 if match ***/
 341 void match()
 342 {
 343    char   *l;        /* Line pointer       */
 344
 345    for (l = lbuf; *l; ++l) {
 346       if (pmatch(l, pbuf))
 347          return(1);
 348    }
 349    return(0);
 350 }
 351
 352 /*** Match partial line with pattern *******************/
 353 char *pmatch(char *line, char *pattern)
 354    /* char               *line;     // (partial) line to match      */
 355    /* char               *pattern;  // (partial) pattern to match   */
 356 {
 357    char   *l;        /* Current line pointer         */
 358    char   *p;        /* Current pattern pointer      */
 359    char   c;         /* Current character            */
 360    char            *e;        /* End for STAR and PLUS match  */
 361    int             op;        /* Pattern operation            */
 362    int             n;         /* Class counter                */
 363    char            *are;      /* Start of STAR match          */
 364
 365    l = line;
 366    if (debug > 1)
 367       printf("pmatch(\"%s\")\n", line);
 368    p = pattern;
 369    while ((op = *p++) != ENDPAT) {
 370       if (debug > 1)
 371          printf("byte[%d] = 0%o, '%c', op = 0%o\n",
 372                l-line, *l, *l, op);
 373       switch(op) {
 374
 375          case CHAR:
 376             if (tolower(*l++) != *p++)
 377                return(0);
 378             break;
 379
 380          case BOL:
 381             if (l != lbuf)
 382                return(0);
 383             break;
 384
 385          case EOL:
 386             if (*l != '\0')
 387                return(0);
 388             break;
 389
 390          case ANY:
 391             if (*l++ == '\0')
 392                return(0);
 393             break;
 394
 395          case DIGIT:
 396             if ((c = *l++) < '0' || (c > '9'))
 397                return(0);
 398             break;
 399
 400          case ALPHA:
 401             c = tolower(*l++);
 402             if (c < 'a' || c > 'z')
 403                return(0);
 404             break;
 405
 406          case NALPHA:
 407             c = tolower(*l++);
 408             if (c >= 'a' && c <= 'z')
 409                break;
 410             else if (c < '0' || c > '9')
 411                return(0);
 412             break;
 413
 414          case PUNCT:
 415             c = *l++;
 416             if (c == 0 || c > ' ')
 417                return(0);
 418             break;
 419
 420          case CLASS:
 421          case NCLASS:
 422             c = tolower(*l++);
 423             n = *p++ & 0377;
 424             do {
 425                if (*p == RANGE) {
 426                   p += 3;
 427                   n -= 2;
 428                   if (c >= p[-2] && c <= p[-1])
 429                      break;
 430                }
 431                else if (c == *p++)
 432                   break;
 433             } while (--n > 1);
 434             if ((op == CLASS) == (n <= 1))
 435                return(0);
 436             if (op == CLASS)
 437                p += n - 2;
 438             break;
 439
 440          case MINUS:
 441             e = pmatch(l, p);       /* Look for a match    */
 442             while (*p++ != ENDPAT); /* Skip over pattern   */
 443             if (e)                  /* Got a match?        */
 444                l = e;               /* Yes, update string  */
 445             break;                  /* Always succeeds     */
 446
 447          case PLUS:                 /* One or more ...     */
 448             if ((l = pmatch(l, p)) == 0)
 449                return(0);           /* Gotta have a match  */
 450          case STAR:                 /* Zero or more ...    */
 451             are = l;                /* Remember line start */
 452             while (*l && (e = pmatch(l, p)))
 453                l = e;               /* Get longest match   */
 454             while (*p++ != ENDPAT); /* Skip over pattern   */
 455             while (l >= are) {      /* Try to match rest   */
 456                if (e = pmatch(l, p))
 457                   return(e);
 458                --l;                 /* Nope, try earlier   */
 459             }
 460             return(0);              /* Nothing else worked */
 461
 462          default:
 463             printf("Bad op code %d\n", op);
 464             error("Cannot happen -- match\n");
 465       }
 466    }
 467    return(l);
 468 }
 469
 470 /*** Report an error ***********************************/
 471 void error(char *s)
 472 {
 473    fprintf(stderr, "%s", s);
 474    exit(1);
 475 }
 476
 477 /*** Main program - parse arguments & grep *************/
 478 int main(int argc, char **argv)
 479 {
 480    char   *p;
 481    int    c, i;
 482    int             gotpattern;
 483
 484    FILE            *f;
 485
 486    if (argc <= 1)
 487       usage("No arguments");
 488    if (argc == 2 && argv[1][0] == '?' && argv[1][1] == 0) {
 489       help(documentation);
 490       help(patdoc);
 491       return 0;
 492    }
 493    nfile = argc-1;
 494    gotpattern = 0;
 495    for (i=1; i < argc; ++i) {
 496       p = argv[i];
 497       if (*p == '-') {
 498          ++p;
 499          while (c = *p++) {
 500             switch(tolower(c)) {
 501
 502                case '?':
 503                   help(documentation);
 504                   break;
 505
 506                case 'C':
 507                case 'c':
 508                   ++cflag;
 509                   break;
 510
 511                case 'D':
 512                case 'd':
 513                   ++debug;
 514                   break;
 515
 516                case 'F':
 517                case 'f':
 518                   ++fflag;
 519                   break;
 520
 521                case 'n':
 522                case 'N':
 523                   ++nflag;
 524                   break;
 525
 526                case 'v':
 527                case 'V':
 528                   ++vflag;
 529                   break;
 530
 531                default:
 532                   usage("Unknown flag");
 533             }
 534          }
 535          argv[i] = 0;
 536          --nfile;
 537       } else if (!gotpattern) {
 538          compile(p);
 539          argv[i] = 0;
 540          ++gotpattern;
 541          --nfile;
 542       }
 543    }
 544    if (!gotpattern)
 545       usage("No pattern");
 546    if (nfile == 0)
 547       grep(stdin, 0);
 548    else {
 549       fflag = fflag ^ (nfile > 0);
 550       for (i=1; i < argc; ++i) {
 551          if (p = argv[i]) {
 552             if ((f=fopen(p, "r")) == NULL)
 553                cant(p);
 554             else {
 555                grep(f, p);
 556                fclose(f);
 557             }
 558          }
 559       }
 560    }
 561    return 0;
 562 }
 563
 564 /* vim: set expandtab ts=4 sw=3 sts=3 tw=80 :*/