/*
* 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h> // tolower()
/*
* grep
*
* Runs on the Decus compiler or on vms, On vms, define as:
* grep :== "$disk:[account]grep" (native)
* grep :== "$disk:[account]grep grep" (Decus)
* See below for more information.
*/
char *documentation[] = {
"grep searches a file for a given pattern. Execute by",
" grep [flags] regular_expression file_list\n",
"Flags are single characters preceded by '-':",
" -c Only a count of matching lines is printed",
" -f Print file name for matching lines switch, see below",
" -n Each line is preceded by its line number",
" -v Only print non-matching lines\n",
"The file_list is a list of files (wildcards are acceptable on RSX modes).",
"\nThe file name is normally printed if there is a file given.",
"The -f flag reverses this action (print name no file, not if more).\n",
0 };
char *patdoc[] = {
"The regular_expression defines the pattern to search for. Upper- and",
"lower-case are always ignored. Blank lines never match. The expression",
"should be quoted to prevent file-name translation.",
"x An ordinary character (not mentioned below) matches that character.",
"'\\' The backslash quotes any character. \"\\$\" matches a dollar-sign.",
"'^' A circumflex at the beginning of an expression matches the",
" beginning of a line.",
"'$' A dollar-sign at the end of an expression matches the end of a line.",
"'.' A period matches any character except \"new-line\".",
"':a' A colon matches a class of characters 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",
" occurrences of that expression: \"fo*\" matches \"f\", \"fo\"",
" \"foo\", etc.",
"'+' An expression followed by a plus sign matches one or more",
" occurrences 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 character in the",
" string is a circumflex, the expression matches any character",
" except \"new-line\" and the characters in the string. For",
" example, \"[xyz]\" matches \"xx\" and \"zyx\", while \"[^xyz]\"",
" matches \"abc\" but not \"axb\". A range of characters 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.",
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];
char *cclass();
char *pmatch();
void store(int);
void error(char *);
void badpat(char *, char *, char *);
int match(void);
/*** Display a file name *******************************/
void file(char *s)
{
printf("File %s:\n", s);
}
/*** Report unopenable file ****************************/
void cant(char *s)
{
fprintf(stderr, "%s: cannot open\n", s);
}
/*** Give good help ************************************/
void help(char **hp)
{
char **dp;
for (dp = hp; *dp; ++dp)
printf("%s\n", *dp);
}
/*** Display usage summary *****************************/
void usage(char *s)
{
fprintf(stderr, "?GREP-E-%s\n", s);
fprintf(stderr,
"Usage: grep [-cfnv] pattern [file ...]. grep ? for help\n");
exit(1);
}
/*** Compile the pattern into global pbuf[] ************/
void compile(char *source)
{
char *s; /* Source string pointer */
char *lp; /* Last pattern pointer */
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 occurrence 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(char *source, char *src)
/* char *source; // Pattern start -- for error msg. */
/* char *src; // Class start */
{
char *s; /* Source pointer */
char *cp; /* Pattern start */
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 **************/
void store(int op)
{
if (pp >= &pbuf[PMAX])
error("Pattern too complex\n");
*pp++ = op;
}
/*** Report a bad pattern specification ****************/
void badpat(char *message, char *source, char *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 %ld, '%c'\n",
stop-source, stop[-1]);
error("?GREP-E-Bad pattern\n");
}
/*** Scan the file for the pattern in pbuf[] ***********/
void grep(FILE *fp, char *fn)
/* FILE *fp; // File to process */
/* char *fn; // File name (for -f option) */
{
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)
printf("%d\t", lno);
printf("%s\n", lbuf);
}
}
}
if (cflag) {
if (fflag && fn)
file(fn);
printf("%d\n", count);
}
}
/*** Match line (lbuf) with pattern (pbuf) return 1 if match ***/
int match()
{
char *l; /* Line pointer */
for (l = lbuf; *l; ++l) {
if (pmatch(l, pbuf))
return(1);
}
return(0);
}
/*** Match partial line with pattern *******************/
char *pmatch(char *line, char *pattern)
/* char *line; // (partial) line to match */
/* char *pattern; // (partial) pattern to match */
{
char *l; /* Current line pointer */
char *p; /* Current pattern pointer */
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[%ld] = 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:
printf("Bad op code %d\n", op);
error("Cannot happen -- match\n");
}
}
return(l);
}
/*** Report an error ***********************************/
void error(char *s)
{
fprintf(stderr, "%s", s);
exit(1);
}
/*** Main program - parse arguments & grep *************/
int main(int argc, char **argv)
{
char *p;
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];
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)
grep(stdin, 0);
else {
fflag = fflag ^ (nfile > 0);
for (i=1; i < argc; ++i) {
if (p = argv[i]) {
if ((f=fopen(p, "r")) == NULL)
cant(p);
else {
grep(f, p);
fclose(f);
}
}
}
}
return 0;
}
/* vim: set expandtab ts=4 sw=3 sts=3 tw=80 :*/