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/* match.c: pattern matching routines */
#include "rc.h"
static int rangematch(char *, char);
/* match() matches a single pattern against a single string. */
extern bool match(char *p, char *m, char *s) {
struct { char *p, *m, *s; } next;
if (m == NULL)
return streq(p, s);
next.s = NULL;
while (*p || *s) {
if (*p) {
if (!*m) {
/* ordinary character */
if (*s == *p) {
p++, m++, s++;
continue;
}
} else switch (*p) {
case '?':
if (*s) {
p++, m++, s++;
continue;
}
break;
case '[': {
int r = 1 + rangematch(p+1, *s);
if (r > 0) {
p += r, m += r, s++;
continue;
}
break;
}
case '*':
next.p = p++;
next.m = m++;
next.s = *s ? s+1 : NULL;
continue;
default:
panic("bad metacharacter in match");
/* NOTREACHED */
return FALSE; /* hush up gcc -Wall */
}
}
if (next.s != NULL) {
p = next.p;
m = next.m;
s = next.s;
continue;
}
return FALSE;
}
return TRUE;
}
/*
From the ed(1) man pages (on ranges):
The `-' is treated as an ordinary character if it occurs first
(or first after an initial ^) or last in the string.
The right square bracket does not terminate the enclosed string
if it is the first character (after an initial `^', if any), in
the bracketed string.
rangematch() matches a single character against a class, and returns
an integer offset to the end of the range on success, or -1 on
failure.
*/
static int rangematch(char *p, char c) {
char *orig = p;
bool neg = (*p == '~');
bool matched = FALSE;
if (neg)
p++;
if (*p == ']') {
p++;
matched = (c == ']');
}
for (; *p != ']'; p++) {
if (*p == '\0')
return c == '[' ? 0 : -1; /* no right-bracket */
if (p[1] == '-' && p[2] != ']') { /* check for [..-..] but ignore [..-] */
if (c >= *p)
matched |= (c <= p[2]);
p += 2;
} else {
matched |= (*p == c);
}
}
if (matched ^ neg)
return p - orig + 1; /* skip the right-bracket */
else
return -1;
}
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