This 'grep' command implementation is a piece of history. It was originally developed for the PDP-11 and then ported to several targets (CP/M, VAX, earlier MS DOS compilers, etc..). Due to the very simple operating systems it had run on, some of its earlier implementations included internal tricks to simulate the file redirection and other similar workarounds which inspired some z88dk feature.
/* * The information in this document is subject to change * without notice and should not be construed as a commitment * by Digital Equipment Corporation or by DECUS. * * Neither Digital Equipment Corporation, DECUS, nor the authors * assume any responsibility for the use or reliability of this * document or the described software. * * Copyright (C) 1980, DECUS * * General permission to copy or modify, but not for profit, is * hereby granted, provided that the above copyright notice is * included and reference made to the fact that reproduction * privileges were granted by DECUS. * * Original authors: * David Conroy, Martin Minow. * */ /* * Build with hand-knit file redirection * (add the following line: #pragma output noredir=1) * zcc +osca -lflosxdos -O3 -DWILDCARD -DREDIR -ogrep.exe grep.c * zcc +cpm -O3 -DWILDCARD ogrep.com grep.c * * Build with Internal z88dk file redirection * zcc +osca -lflosxdos -O3 -DWILDCARD -ogrep.exe grep.c * zcc +cpm -DWILDCARD -O3 -ogrep.com grep.c * * No file redirection at all (faster and smaller): * (add the following line: #pragma output noredir=1) * zcc +osca -lflosdos -DFLOS -O3 -ogrep.exe grep.c * * The CP/M library can be rebuilt to support devices by rebuilding cpm_clib.lib * Enter in z88dk/libsrc/fcntl and 'make clean' * Edit cpm.h to congifure the DEVICES mode, rebuild the lib and copy it in 'clibs' * * */ #include <stdio.h> #include <stdlib.h> #include <ctype.h> #include <unistd.h> /* * Wildcards are supported by z88dk on FLOS and CP/M */ #ifdef WILDCARD int x; #endif char *documentation[] = { //"grep searches a file for a given pattern", //"Execute by:", "", #ifdef REDIR " grep [flg] reg_expr file_list [>ofile]", #else " grep [flags] regular_expr file_list", #endif "", "Flags are single chars preceeded by '-':", " -c Print count of matching lines", " -f alt. 'file name' display action ", " -n Print line numbers", " -v Only print non-matching lines", "", 0 }; char *patdoc[] = { "Valid regular_expr elements:", "", "Upper- and lower-case are always ignored", "Blank lines never match.", "", "x, '\\', \"\\$\", '^', '$'", "'.', ':a', ':d', ':n', \": \", ': ',", "'*', \"fo*\", \"f\", \"foo\", etc.", "'+', \"fo+\", '-', '[]', \"[xyz]\"", "", "See grep.txt for more details.", 0}; #define LMAX 512 #define PMAX 256 #define CHAR 1 #define BOL 2 #define EOL 3 #define ANY 4 #define CLASS 5 #define NCLASS 6 #define STAR 7 #define PLUS 8 #define MINUS 9 #define ALPHA 10 #define DIGIT 11 #define NALPHA 12 #define PUNCT 13 #define RANGE 14 #define ENDPAT 15 int cflag=0, fflag=0, nflag=0, vflag=0, nfile=0, debug=0; char *pp, lbuf[LMAX], pbuf[PMAX]; extern char *cclass(), *pmatch(); /*** Main program - parse arguments & grep *************/ main(argc, argv) int argc; char *argv[]; { register char *p; register int c, i; int gotpattern; FILE *f; if (argc <= 1) usage("No arguments"); if (argc == 2 && argv[1][0] == '?' && argv[1][1] == 0) { help(documentation); help(patdoc); return(0); } nfile = argc-1; gotpattern = 0; for (i=1; i < argc; ++i) { p = argv[i]; #ifdef REDIR /* * Hand-knit I/O redirection for vms */ if (*p == '<') { if (p[1]==0) { fprintf(stderr, "Invalid input file\n"); exit (0); } else freopen(&p[1], "r", stdin); argv[i] = NULL; continue; } if (*p == '>') { if (p[1] == '>') if (p[2]==0) { fprintf(stderr, "Invalid output file\n"); exit (0); } else { freopen(&p[2], "a", stdout); } else if (p[1]==0) { fprintf(stderr, "Invalid output file\n"); exit (0); } else { freopen(&p[1], "w", stdout); } argv[i] = NULL; continue; } #endif if (*p == '-') { ++p; while (c = *p++) { switch(tolower(c)) { case '?': help(documentation); break; case 'C': case 'c': ++cflag; break; case 'D': case 'd': ++debug; break; case 'F': case 'f': ++fflag; break; case 'n': case 'N': ++nflag; break; case 'v': case 'V': ++vflag; break; default: usage("Unknown flag"); } } argv[i] = 0; --nfile; } else if (!gotpattern) { compile(p); argv[i] = 0; ++gotpattern; --nfile; } } if (!gotpattern) usage("No pattern"); if (nfile == 0) { if (isatty(stdin)) usage("No input file given"); else grep(stdin, 0); return(0); } else { fflag = fflag ^ (nfile > 0); for (i=1; i < argc; ++i) { if (p = argv[i]) { #ifdef WILDCARD if ((x=dir_move_first())!=0) return(0); while (x == 0) { if (wcmatch(p,dir_get_entry_name())) { if (!dir_get_entry_type()) { f = fopen(dir_get_entry_name(), "r"); grep(f, dir_get_entry_name()); fclose(f); } } x = dir_move_next(); } #else if ((f=fopen(p, "r")) == NULL) cant(p); else { grep(f, p); fclose(f); } #endif } } } } /*** Display a file name *******************************/ file(s) char *s; { fprintf(stdout,"File %s:\n", s); } /*** Report unopenable file ****************************/ cant(s) char *s; { fprintf(stderr, "%s: cannot open\n", s); } /*** Give good help ************************************/ help(hp) char **hp; { register char **dp; for (dp = hp; *dp; ++dp) fprintf(stderr,"%s\n", *dp); } /*** Display usage summary *****************************/ usage(s) char *s; { fprintf(stderr, "Error: %s\n", s); fprintf(stderr, "Usage: grep [-cfnv] pattern [file ...]. grep ? for help\n"); exit(0); } /*** Compile the pattern into global pbuf[] ************/ compile(source) char *source; /* Pattern to compile */ { register char *s; /* Source string pointer */ register char *lp; /* Last pattern pointer */ register int c; /* Current character */ int o; /* Temp */ char *spp; /* Save beginning of pattern */ s = source; if (debug) printf("Pattern = \"%s\"\n", s); pp = pbuf; while (c = *s++) { /* * STAR, PLUS and MINUS are special. */ if (c == '*' || c == '+' || c == '-') { if (pp == pbuf || (o=pp[-1]) == BOL || o == EOL || o == STAR || o == PLUS || o == MINUS) badpat("Illegal occurrance op.", source, s); store(ENDPAT); store(ENDPAT); spp = pp; /* Save pattern end */ while (--pp > lp) /* Move pattern down */ *pp = pp[-1]; /* one byte */ *pp = (c == '*') ? STAR : (c == '-') ? MINUS : PLUS; pp = spp; /* Restore pattern end */ continue; } /* * All the rest. */ lp = pp; /* Remember start */ switch(c) { case '^': store(BOL); break; case '$': store(EOL); break; case '.': store(ANY); break; case '[': s = cclass(source, s); break; case ':': if (*s) { switch(tolower(c = *s++)) { case 'a': case 'A': store(ALPHA); break; case 'd': case 'D': store(DIGIT); break; case 'n': case 'N': store(NALPHA); break; case ' ': store(PUNCT); break; default: badpat("Unknown : type", source, s); } break; } else badpat("No : type", source, s); case '\\': if (*s) c = *s++; default: store(CHAR); store(tolower(c)); } } store(ENDPAT); store(0); /* Terminate string */ if (debug) { for (lp = pbuf; lp < pp;) { if ((c = (*lp++ & 0377)) < ' ') printf("\\%o ", c); else printf("%c ", c); } printf("\n"); } } /*** Compile a class (within []) ***********************/ char *cclass(source, src) char *source; /* Pattern start -- for error msg. */ char *src; /* Class start */ { register char *s; /* Source pointer */ register char *cp; /* Pattern start */ register int c; /* Current character */ int o; /* Temp */ s = src; o = CLASS; if (*s == '^') { ++s; o = NCLASS; } store(o); cp = pp; store(0); /* Byte count */ while ((c = *s++) && c!=']') { if (c == '\\') { /* Store quoted char */ if ((c = *s++) == '\0') /* Gotta get something */ badpat("Class terminates badly", source, s); else store(tolower(c)); } else if (c == '-' && (pp - cp) > 1 && *s != ']' && *s != '\0') { c = pp[-1]; /* Range start */ pp[-1] = RANGE; /* Range signal */ store(c); /* Re-store start */ c = *s++; /* Get end char and*/ store(tolower(c)); /* Store it */ } else { store(tolower(c)); /* Store normal char */ } } if (c != ']') badpat("Unterminated class", source, s); if ((c = (pp - cp)) >= 256) badpat("Class too large", source, s); if (c == 0) badpat("Empty class", source, s); *cp = c; return(s); } /*** Store an entry in the pattern buffer **************/ store(op) int op; { if (pp >= &pbuf[PMAX]) error("Pattern too complex\n"); *pp++ = op; } /*** Report a bad pattern specification ****************/ badpat(message, source, stop) char *message; /* Error message */ char *source; /* Pattern start */ char *stop; /* Pattern end */ { fprintf(stderr, "-GREP-E-%s, pattern is\"%s\"\n", message, source); fprintf(stderr, "-GREP-E-Stopped at byte %d, '%c'\n", stop-source, stop[-1]); error("?GREP-E-Bad pattern\n"); } /*** Scan the file for the pattern in pbuf[] ***********/ grep(fp, fn) FILE *fp; /* File to process */ char *fn; /* File name (for -f option) */ { register int lno, count, m; lno = 0; count = 0; while (fgets(lbuf, LMAX, fp)) { ++lno; m = match(); if ((m && !vflag) || (!m && vflag)) { ++count; if (!cflag) { if (fflag && fn) { file(fn); fn = 0; } if (nflag) fprintf(stdout,"%d\t", lno); //fprintf(stdout,"%s\n", lbuf); fprintf(stdout,"%s", lbuf); } } } if (cflag) { if (fflag && fn) file(fn); fprintf(stdout,"%d\n", count); } } /*** Match line (lbuf) with pattern (pbuf) return 1 if match ***/ match() { register char *l; /* Line pointer */ for (l = lbuf; *l; ++l) { if (pmatch(l, pbuf)) return(1); } return(0); } /*** Match partial line with pattern *******************/ char *pmatch(line, pattern) char *line; /* (partial) line to match */ char *pattern; /* (partial) pattern to match */ { register char *l; /* Current line pointer */ register char *p; /* Current pattern pointer */ register char c; /* Current character */ char *e; /* End for STAR and PLUS match */ int op; /* Pattern operation */ int n; /* Class counter */ char *are; /* Start of STAR match */ l = line; if (debug > 1) printf("pmatch(\"%s\")\n", line); p = pattern; while ((op = *p++) != ENDPAT) { if (debug > 1) printf("byte[%d] = 0%o, '%c', op = 0%o\n", l-line, *l, *l, op); switch(op) { case CHAR: if (tolower(*l++) != *p++) return(0); break; case BOL: if (l != lbuf) return(0); break; case EOL: if (*l != '\0') return(0); break; case ANY: if (*l++ == '\0') return(0); break; case DIGIT: if ((c = *l++) < '0' || (c > '9')) return(0); break; case ALPHA: c = tolower(*l++); if (c < 'a' || c > 'z') return(0); break; case NALPHA: c = tolower(*l++); if (c >= 'a' && c <= 'z') break; else if (c < '0' || c > '9') return(0); break; case PUNCT: c = *l++; if (c == 0 || c > ' ') return(0); break; case CLASS: case NCLASS: c = tolower(*l++); n = *p++ & 0377; do { if (*p == RANGE) { p += 3; n -= 2; if (c >= p[-2] && c <= p[-1]) break; } else if (c == *p++) break; } while (--n > 1); if ((op == CLASS) == (n <= 1)) return(0); if (op == CLASS) p += n - 2; break; case MINUS: e = pmatch(l, p); /* Look for a match */ while (*p++ != ENDPAT); /* Skip over pattern */ if (e) /* Got a match? */ l = e; /* Yes, update string */ break; /* Always succeeds */ case PLUS: /* One or more ... */ if ((l = pmatch(l, p)) == 0) return(0); /* Gotta have a match */ case STAR: /* Zero or more ... */ are = l; /* Remember line start */ while (*l && (e = pmatch(l, p))) l = e; /* Get longest match */ while (*p++ != ENDPAT); /* Skip over pattern */ while (l >= are) { /* Try to match rest */ if (e = pmatch(l, p)) return(e); --l; /* Nope, try earlier */ } return(0); /* Nothing else worked */ default: fprintf(stderr,"Bad op code %d\n", op); error("Cannot happen -- match\n"); } } return(l); } /*** Report an error ***********************************/ error(s) char *s; { fprintf(stderr, "%s", s); exit(0); }
grep.txt
grep searches a file for a given pattern Execute by grep [flags] regular_expr file_list Flags are single chars preceeded by '-': -c Only a count of matching lines is printed -f Print file name for matching lines switch, see below -n Each line is preceeded by its line number -v Only print non-matching lines The file_list is a list of files The file name is normally printed if there is a file given. The -f flag reverses this action (print name no file, not if more). The regular_expression defines the pat- tern to search for. Upper- and lower- case are always ignored. Blank lines never match. The expression should be quoted to prevent filename translation x An ordinary character (not mentioned below) matches that character. '\' The backslash quotes any char. "\$" matches a dollar-sign. '^' A circumflex at the beginning of expression matches the beginning of a line. '$' A dollar-sign at the end of an expr matches the end of a line '.' A period matches any character except "new-line". ':a' A colon matches a class of chars described by the following ':d' character. ":a" matches any alphabetic, ":d" matches digits, ':n' ":n" matches alphanumerics, ": " matches spaces, tabs, and ': ' other control characters, such as new-line. '*' An expression followed by an asterisk matches zero or more occurrances of that expression: "fo*" matches "f", "fo" "foo", etc. '+' An expression followed by a plus sign matches one or more occurrances of that expression: "fo+" matches "fo", etc. '-' An expression followed by a minus sign optionally matches the expression. '[]' A string enclosed in square brackets matches any character in that string, but no others. If the first char in the string is a circumflex, the expr matches any char except "new-line" and the chars in the string. For example, "[xyz]" matches "xx" and "zyx",while "[^xyz]" matches "abc" but not "axb". A range of chars may be specified by two characters separated by "-". Note that, [a-z] matches alphabetics, while [z-a] never matches. The concatenation of regular expressions is a regular expression.