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| Commit | Line | Data |
|---|---|---|
| 9d25673b C |
1 | /* match.c: pattern matching routines */ |
| 2 | ||
| 3 | #include "rc.h" | |
| 4 | ||
| 5 | static int rangematch(char *, char); | |
| 6 | ||
| 7 | enum { RANGE_FAIL = -1, RANGE_ERROR = -2 }; | |
| 8 | ||
| 9 | /* match() matches a single pattern against a single string. */ | |
| 10 | ||
| 11 | extern bool match(char *p, char *m, char *s) { | |
| 12 | int i, j; | |
| 13 | if (m == NULL) | |
| 14 | return streq(p, s); | |
| 15 | i = 0; | |
| 16 | while (1) { | |
| 17 | if (p[i] == '\0') | |
| 18 | return *s == '\0'; | |
| 19 | else if (m[i]) { | |
| 20 | switch (p[i++]) { | |
| 21 | case '?': | |
| 22 | if (*s++ == '\0') | |
| 23 | return FALSE; | |
| 24 | break; | |
| 25 | case '*': | |
| 26 | while (p[i] == '*' && m[i] == 1) /* collapse multiple stars */ | |
| 27 | i++; | |
| 28 | if (p[i] == '\0') /* star at end of pattern? */ | |
| 29 | return TRUE; | |
| 30 | while (*s != '\0') | |
| 31 | if (match(p + i, m + i, s++)) | |
| 32 | return TRUE; | |
| 33 | return FALSE; | |
| 34 | case '[': | |
| 35 | if (*s == '\0') | |
| 36 | return FALSE; | |
| 37 | switch (j = rangematch(p + i, *s)) { | |
| 38 | default: | |
| 39 | i += j; | |
| 40 | break; | |
| 41 | case RANGE_FAIL: | |
| 42 | return FALSE; | |
| 43 | case RANGE_ERROR: | |
| 44 | if (*s != '[') | |
| 45 | return FALSE; | |
| 46 | } | |
| 47 | s++; | |
| 48 | break; | |
| 49 | default: | |
| 50 | panic("bad metacharacter in match"); | |
| 51 | /* NOTREACHED */ | |
| 52 | return FALSE; /* hush up gcc -Wall */ | |
| 53 | } | |
| 54 | } else if (p[i++] != *s++) | |
| 55 | return FALSE; | |
| 56 | } | |
| 57 | } | |
| 58 | ||
| 59 | /* | |
| 60 | From the ed(1) man pages (on ranges): | |
| 61 | ||
| 62 | The `-' is treated as an ordinary character if it occurs first | |
| 63 | (or first after an initial ^) or last in the string. | |
| 64 | ||
| 65 | The right square bracket does not terminate the enclosed string | |
| 66 | if it is the first character (after an initial `^', if any), in | |
| 67 | the bracketed string. | |
| 68 | ||
| 69 | rangematch() matches a single character against a class, and returns | |
| 70 | an integer offset to the end of the range on success, or -1 on | |
| 71 | failure. | |
| 72 | */ | |
| 73 | ||
| 74 | static int rangematch(char *p, char c) { | |
| 75 | char *orig = p; | |
| 76 | bool neg = (*p == '~'); | |
| 77 | bool matched = FALSE; | |
| 78 | if (neg) | |
| 79 | p++; | |
| 80 | if (*p == ']') { | |
| 81 | p++; | |
| 82 | matched = (c == ']'); | |
| 83 | } | |
| 84 | for (; *p != ']'; p++) { | |
| 85 | if (*p == '\0') | |
| 86 | return RANGE_ERROR; /* bad syntax */ | |
| 87 | if (p[1] == '-' && p[2] != ']') { /* check for [..-..] but ignore [..-] */ | |
| 88 | if (c >= *p) | |
| 89 | matched |= (c <= p[2]); | |
| 90 | p += 2; | |
| 91 | } else { | |
| 92 | matched |= (*p == c); | |
| 93 | } | |
| 94 | } | |
| 95 | if (matched ^ neg) | |
| 96 | return p - orig + 1; /* skip the right-bracket */ | |
| 97 | else | |
| 98 | return RANGE_FAIL; | |
| 99 | } |