minix/commands/yap/pattern.c

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2005-04-21 16:53:53 +02:00
/* Copyright (c) 1985 Ceriel J.H. Jacobs */
# ifndef lint
static char rcsid[] = "$Header$";
# endif not lint
# define _PATTERN_
# include "in_all.h"
# include "pattern.h"
# include "getline.h"
# if V8_REGEX
# include <regexp.h>
# endif V8_REGEX
/*
* Interface to regular expression routines.
* Also: simple minded patterns without meta-characters.
*/
# if USG_REGEX
static char *pattern; /* Pointer to compiled pattern */
char *regcmp(), *regex();
# endif USG_REGEX
# if V8_REGEX
static struct regexp *pattern;
static char *rc_error;
struct regexp *regcomp();
# endif V8_REGEX
# if USG_REGEX || V8_REGEX
/*
* Compile a new pattern, but first free previous result.
*/
char *
re_comp(s) char *s; {
if (!*s) {
/*
* user wants previous pattern
*/
return (char *) 0;
}
if (pattern) {
/*
* there was a compiled pattern
*/
free(pattern);
pattern = 0;
}
# if USG_REGEX
return (pattern = regcmp(s, (char *) 0)) ?
(char *) 0 :
"Error in pattern";
# endif USG_REGEX
# if V8_REGEX
pattern = regcomp(s);
if (pattern) return (char *) 0;
if (rc_error) return rc_error;
return "Error in pattern";
# endif V8_REGEX
}
# if V8_REGEX
VOID
regerror(str) char *str; {
rc_error = str;
}
# endif V8_REGEX
/*
* Search for compiled pattern in string "s". Return 0 if not found.
*/
re_exec(s) char *s; {
# if USG_REGEX
return !(regex(pattern,s) == 0);
# endif USG_REGEX
# if V8_REGEX
# if _MINIX
return regexec(pattern,s,1);
# else
return regexec(pattern,s);
# endif
# endif V8_REGEX
}
# else
# ifndef BSD_REGEX
/*
* In this case, simple minded pattern search without meta-characters
*/
char *strcpy();
static char *pattern;
/*
* re_comp : Just remember pattern.
*/
char *
re_comp(s) char *s; {
if (!*s) {
/*
* User wants previous pattern
*/
if (!pattern) {
return "No previous regular expression";
}
return (char *) 0;
}
if (pattern) {
/*
* Free old pattern
*/
free(pattern);
}
pattern = alloc((unsigned) (strlen(s) + 1), 0);
(VOID) strcpy(pattern,s);
return (char *) 0;
}
/*
* re-exec : Simple minded pattern matcher
*/
re_exec(s) register char *s; {
register char *ppat, *pstr;
for (; *s; s++) {
/*
* As long as there are characters ...
*/
ppat = pattern; /* Try the pattern again */
pstr = s;
while (*ppat == *pstr) {
if (*++ppat == '\0') {
/*
* The pattern matched! Report success
*/
return 1;
}
if (*++pstr == '\0') {
/*
* Not enough characters left in the string.
* Report failure
*/
return 0;
}
}
}
return 0; /* Failure */
}
# endif not BSD_REGEX
# endif