/*
* An implementation of what I call the "Sea of Stars" algorithm for
* POSIX fnmatch(). The basic idea is that we factor the pattern into
* a head component (which we match first and can reject without ever
* measuring the length of the string), an optional tail component
* (which only exists if the pattern contains at least one star), and
* an optional "sea of stars", a set of star-separated components
* between the head and tail. After the head and tail matches have
* been removed from the input string, the components in the "sea of
* stars" are matched sequentially by searching for their first
* occurrence past the end of the previous match.
*
* - Rich Felker, April 2012
*/
#include <string.h>
#include <fnmatch.h>
#include <stdlib.h>
#include <wchar.h>
#include <wctype.h>
#define END -1
#define UNMATCHABLE -2
#define BRACKET -3
#define QUESTION -4
#define STAR -5
static int str_next(const char *str, size_t n, size_t *step)
{
if (!n) {
*step = 0;
return 0;
}
if (str[0] >= 128U) {
wchar_t wc;
int k = mbtowc(&wc, str, n);
if (k<0) {
*step = 1;
return -1;
}
*step = k;
return wc;
}
*step = 1;
return str[0];
}
static int pat_next(const char *pat, size_t m, size_t *step, int flags)
{
int esc = 0;
if (!m || !*pat) {
*step = 0;
return END;
}
*step = 1;
if (pat[0]=='\\' && !(flags & FNM_NOESCAPE)) {
*step = 2;
pat++;
esc = 1;
goto escaped;
}
if (pat[0]=='[') {
size_t k = 1;
if (k<m) if (pat[k] == '^' || pat[k] == '!') k++;
if (k<m) if (pat[k] == ']') k++;
for (; k<m && pat[k] && pat[k]!=']'; k++) {
if (k+1<m && pat[k+1] && pat[k]=='[' && (pat[k+1]==':' || pat[k+1]=='.' || pat[k+1]=='=')) {
int z = pat[k+1];
k+=2;
if (k<m && pat[k]) k++;
while (k<m && pat[k] && (pat[k-1]!=z || pat[k]!=']')) k++;
if (k==m || !pat[k]) break;
}
}
if (k==m || !pat[k]) {
*step = 1;
return '[';
}
*step = k+1;
return BRACKET;
}
if (pat[0] == '*')
return STAR;
if (pat[0] == '?')
return QUESTION;
escaped:
if (pat[0] >= 128U) {
wchar_t wc;
int k = mbtowc(&wc, pat, m);
if (k<0) {
*step = 0;
return UNMATCHABLE;
}
*step = k + esc;
return wc;
}
return pat[0];
}
static int match_bracket(const char *p, int k)
{
wchar_t wc;
int inv = 0;
p++;
if (*p=='^' || *p=='!') {
inv = 1;
p++;
}
if (*p==']') {
if (k==']') return !inv;
p++;
} else if (*p=='-') {
if (k=='-') return !inv;
p++;
}
wc = p[-1];
for (; *p != ']'; p++) {
if (p[0]=='-' && p[1]!=']') {
wchar_t wc2;
int l = mbtowc(&wc2, p+1, 4);
if (l < 0) return 0;
if (wc<=wc2 && (unsigned)k-wc <= wc2-wc) return !inv;
p += l-1;
continue;
}
if (p[0]=='[' && (p[1]==':' || p[1]=='.' || p[1]=='=')) {
const char *p0 = p+2;
int z = p[1];
p+=3;
while (p[-1]!=z || p[0]!=']') p++;
if (z == ':' && p-1-p0 < 16) {
char buf[16];
memcpy(buf, p0, p-1-p0);
buf[p-1-p0] = 0;
if (iswctype(k, wctype(buf))) return !inv;
}
continue;
}
if (*p < 128U) {
wc = (unsigned char)*p;
} else {
int l = mbtowc(&wc, p, 4);
if (l < 0) return 0;
p += l-1;
}
if (wc==k) return !inv;
}
return inv;
}
static int fnmatch_internal(const char *pat, size_t m, const char *str, size_t n, int flags)
{
const char *p, *ptail, *endpat;
const char *s, *stail, *endstr;
size_t pinc, sinc, tailcnt=0;
int c, k;
if (flags & FNM_PERIOD) {
if (*str == '.' && *pat != '.')
return FNM_NOMATCH;
}
for (;;) {
switch ((c = pat_next(pat, m, &pinc, flags))) {
case UNMATCHABLE:
return FNM_NOMATCH;
case STAR:
pat++;
m--;
break;
default:
k = str_next(str, n, &sinc);
if (k <= 0)
return (c==END) ? 0 : FNM_NOMATCH;
str += sinc;
n -= sinc;
if (c == BRACKET) {
if (!match_bracket(pat, k))
return FNM_NOMATCH;
} else if (c != QUESTION && k != c) {
return FNM_NOMATCH;
}
pat+=pinc;
m-=pinc;
continue;
}
break;
}
/* Compute real pat length if it was initially unknown/-1 */
m = strnlen(pat, m);
endpat = pat + m;
/* Find the last * in pat and count chars needed after it */
for (p=ptail=pat; p<endpat; p+=pinc) {
switch (pat_next(p, endpat-p, &pinc, flags)) {
case UNMATCHABLE:
return FNM_NOMATCH;
case STAR:
tailcnt=0;
ptail = p+1;
break;
default:
tailcnt++;
break;
}
}
/* Past this point we need not check for UNMATCHABLE in pat,
* because all of pat has already been parsed once. */
/* Compute real str length if it was initially unknown/-1 */
n = strnlen(str, n);
endstr = str + n;
if (n < tailcnt) return FNM_NOMATCH;
/* Find the final tailcnt chars of str, accounting for UTF-8.
* On illegal sequences we may get it wrong, but in that case
* we necessarily have a matching failure anyway. */
for (s=endstr; s>str && tailcnt; tailcnt--) {
if (s[-1] < 128U) s--;
else while ((unsigned char)*--s-0x80U<0x40 && s>str);
}
if (tailcnt) return FNM_NOMATCH;
stail = s;
/* Check that the pat and str tails match */
p = ptail;
for (;;) {
c = pat_next(p, endpat-p, &pinc, flags);
p += pinc;
if ((k = str_next(s, endstr-s, &sinc)) <= 0) {
if (c != END) return FNM_NOMATCH;
break;
}
s += sinc;
if (c == BRACKET) {
if (!match_bracket(p-pinc, k))
return FNM_NOMATCH;
} else if (c != QUESTION && k != c) {
return FNM_NOMATCH;
}
}
/* We're all done with the tails now, so throw them out */
endstr = stail;
endpat = ptail;
/* Match pattern components until there are none left */
while (pat<endpat) {
p = pat;
s = str;
for (;;) {
c = pat_next(p, endpat-p, &pinc, flags);
p += pinc;
/* Encountering * completes/commits a component */
if (c == STAR) {
pat = p;
str = s;
break;
}
k = str_next(s, endstr-s, &sinc);
if (!k)
return FNM_NOMATCH;
if (c == BRACKET) {
if (!match_bracket(p-pinc, k))
break;
} else if (c != QUESTION && k != c) {
break;
}
s += sinc;
}
if (c == STAR) continue;
/* If we failed, advance str, by 1 char if it's a valid
* char, or past all invalid bytes otherwise. */
k = str_next(str, endstr-str, &sinc);
if (k > 0) str += sinc;
else for (str++; str_next(str, endstr-str, &sinc)<0; str++);
}
return 0;
}
int fnmatch(const char *pat, const char *str, int flags)
{
const char *s, *p;
size_t inc;
int c;
if (flags & FNM_PATHNAME) for (;;) {
for (s=str; *s && *s!='/'; s++);
for (p=pat; (c=pat_next(p, -1, &inc, flags))!=END && c!='/'; p+=inc);
if (*s && *p!=*s) return FNM_NOMATCH;
if (fnmatch_internal(pat, p-pat, str, s-str, flags))
return FNM_NOMATCH;
if (!*s && c==END) return 0;
str = s+1;
pat = p+1;
}
return fnmatch_internal(pat, -1, str, -1, flags);
}
