2 * An implementation of what I call the "Sea of Stars" algorithm for
3 * POSIX fnmatch(). The basic idea is that we factor the pattern into
4 * a head component (which we match first and can reject without ever
5 * measuring the length of the string), an optional tail component
6 * (which only exists if the pattern contains at least one star), and
7 * an optional "sea of stars", a set of star-separated components
8 * between the head and tail. After the head and tail matches have
9 * been removed from the input string, the components in the "sea of
10 * stars" are matched sequentially by searching for their first
11 * occurrence past the end of the previous match.
13 * - Rich Felker, April 2012
21 #include "locale_impl.h"
24 #define UNMATCHABLE -2
29 static int str_next(const char *str, size_t n, size_t *step)
37 int k = mbtowc(&wc, str, n);
49 static int pat_next(const char *pat, size_t m, size_t *step, int flags)
57 if (pat[0]=='\\' && pat[1] && !(flags & FNM_NOESCAPE)) {
65 if (k<m) if (pat[k] == '^' || pat[k] == '!') k++;
66 if (k<m) if (pat[k] == ']') k++;
67 for (; k<m && pat[k] && pat[k]!=']'; k++) {
68 if (k+1<m && pat[k+1] && pat[k]=='[' && (pat[k+1]==':' || pat[k+1]=='.' || pat[k+1]=='=')) {
71 if (k<m && pat[k]) k++;
72 while (k<m && pat[k] && (pat[k-1]!=z || pat[k]!=']')) k++;
73 if (k==m || !pat[k]) break;
76 if (k==m || !pat[k]) {
90 int k = mbtowc(&wc, pat, m);
101 static int casefold(int k)
104 return c == k ? towlower(k) : c;
107 static int match_bracket(const char *p, int k, int kfold)
112 if (*p=='^' || *p=='!') {
117 if (k==']') return !inv;
119 } else if (*p=='-') {
120 if (k=='-') return !inv;
124 for (; *p != ']'; p++) {
125 if (p[0]=='-' && p[1]!=']') {
127 int l = mbtowc(&wc2, p+1, 4);
130 if ((unsigned)k-wc <= wc2-wc ||
131 (unsigned)kfold-wc <= wc2-wc)
136 if (p[0]=='[' && (p[1]==':' || p[1]=='.' || p[1]=='=')) {
137 const char *p0 = p+2;
140 while (p[-1]!=z || p[0]!=']') p++;
141 if (z == ':' && p-1-p0 < 16) {
143 memcpy(buf, p0, p-1-p0);
145 if (iswctype(k, wctype(buf)) ||
146 iswctype(kfold, wctype(buf)))
152 wc = (unsigned char)*p;
154 int l = mbtowc(&wc, p, 4);
158 if (wc==k || wc==kfold) return !inv;
163 static int fnmatch_internal(const char *pat, size_t m, const char *str, size_t n, int flags)
165 const char *p, *ptail, *endpat;
166 const char *s, *stail, *endstr;
167 size_t pinc, sinc, tailcnt=0;
170 if (flags & FNM_PERIOD) {
171 if (*str == '.' && *pat != '.')
175 switch ((c = pat_next(pat, m, &pinc, flags))) {
183 k = str_next(str, n, &sinc);
185 return (c==END) ? 0 : FNM_NOMATCH;
188 kfold = flags & FNM_CASEFOLD ? casefold(k) : k;
190 if (!match_bracket(pat, k, kfold))
192 } else if (c != QUESTION && k != c && kfold != c) {
202 /* Compute real pat length if it was initially unknown/-1 */
206 /* Find the last * in pat and count chars needed after it */
207 for (p=ptail=pat; p<endpat; p+=pinc) {
208 switch (pat_next(p, endpat-p, &pinc, flags)) {
221 /* Past this point we need not check for UNMATCHABLE in pat,
222 * because all of pat has already been parsed once. */
224 /* Compute real str length if it was initially unknown/-1 */
227 if (n < tailcnt) return FNM_NOMATCH;
229 /* Find the final tailcnt chars of str, accounting for UTF-8.
230 * On illegal sequences we may get it wrong, but in that case
231 * we necessarily have a matching failure anyway. */
232 for (s=endstr; s>str && tailcnt; tailcnt--) {
233 if (s[-1] < 128U || MB_CUR_MAX==1) s--;
234 else while ((unsigned char)*--s-0x80U<0x40 && s>str);
236 if (tailcnt) return FNM_NOMATCH;
239 /* Check that the pat and str tails match */
242 c = pat_next(p, endpat-p, &pinc, flags);
244 if ((k = str_next(s, endstr-s, &sinc)) <= 0) {
245 if (c != END) return FNM_NOMATCH;
249 kfold = flags & FNM_CASEFOLD ? casefold(k) : k;
251 if (!match_bracket(p-pinc, k, kfold))
253 } else if (c != QUESTION && k != c && kfold != c) {
258 /* We're all done with the tails now, so throw them out */
262 /* Match pattern components until there are none left */
267 c = pat_next(p, endpat-p, &pinc, flags);
269 /* Encountering * completes/commits a component */
275 k = str_next(s, endstr-s, &sinc);
278 kfold = flags & FNM_CASEFOLD ? casefold(k) : k;
280 if (!match_bracket(p-pinc, k, kfold))
282 } else if (c != QUESTION && k != c && kfold != c) {
287 if (c == STAR) continue;
288 /* If we failed, advance str, by 1 char if it's a valid
289 * char, or past all invalid bytes otherwise. */
290 k = str_next(str, endstr-str, &sinc);
291 if (k > 0) str += sinc;
292 else for (str++; str_next(str, endstr-str, &sinc)<0; str++);
298 int fnmatch(const char *pat, const char *str, int flags)
303 if (flags & FNM_PATHNAME) for (;;) {
304 for (s=str; *s && *s!='/'; s++);
305 for (p=pat; (c=pat_next(p, -1, &inc, flags))!=END && c!='/'; p+=inc);
306 if (c!=*s && (!*s || !(flags & FNM_LEADING_DIR)))
308 if (fnmatch_internal(pat, p-pat, str, s-str, flags))
313 } else if (flags & FNM_LEADING_DIR) {
314 for (s=str; *s; s++) {
315 if (*s != '/') continue;
316 if (!fnmatch_internal(pat, -1, str, s-str, flags))
320 return fnmatch_internal(pat, -1, str, -1, flags);