shell/match.c

   1 /*
   2  * ##/%% variable matching code ripped out of ash shell for code sharing
   3  *
   4  * This code is derived from software contributed to Berkeley by
   5  * Kenneth Almquist.
   6  *
   7  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   8  *
   9  * Copyright (c) 1989, 1991, 1993, 1994
  10  *      The Regents of the University of California.  All rights reserved.
  11  *
  12  * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
  13  * was re-ported from NetBSD and debianized.
  14  */
  15 #ifdef STANDALONE
  16 # include <stdbool.h>
  17 # include <stdio.h>
  18 # include <stdlib.h>
  19 # include <string.h>
  20 # include <unistd.h>
  21 #else
  22 # include "libbb.h"
  23 #endif
  24 #include <fnmatch.h>
  25 #include "match.h"
  26
  27 #define pmatch(a, b) !fnmatch((a), (b), 0)
  28
  29 char *scanleft(char *string, char *pattern, bool match_at_left)
  30 {
  31         char c;
  32         char *loc = string;
  33
  34         do {
  35                 int match;
  36                 const char *s;
  37
  38                 c = *loc;
  39                 if (match_at_left) {
  40                         *loc = '\0';
  41                         s = string;
  42                 } else
  43                         s = loc;
  44                 match = pmatch(pattern, s);
  45                 *loc = c;
  46
  47                 if (match)
  48                         return loc;
  49
  50                 loc++;
  51         } while (c);
  52
  53         return NULL;
  54 }
  55
  56 char *scanright(char *string, char *pattern, bool match_at_left)
  57 {
  58         char c;
  59         char *loc = string + strlen(string);
  60
  61         while (loc >= string) {
  62                 int match;
  63                 const char *s;
  64
  65                 c = *loc;
  66                 if (match_at_left) {
  67                         *loc = '\0';
  68                         s = string;
  69                 } else
  70                         s = loc;
  71                 match = pmatch(pattern, s);
  72                 *loc = c;
  73
  74                 if (match)
  75                         return loc;
  76
  77                 loc--;
  78         }
  79
  80         return NULL;
  81 }
  82
  83 #ifdef STANDALONE
  84 int main(int argc, char *argv[])
  85 {
  86         char *string;
  87         char *op;
  88         char *pattern;
  89         bool match_at_left;
  90         char *loc;
  91
  92         int i;
  93
  94         if (argc == 1) {
  95                 puts(
  96                         "Usage: match <test> [test...]\n\n"
  97                         "Where a <test> is the form: <string><op><match>\n"
  98                         "This is to test the shell ${var#val} expression type.\n\n"
  99                         "e.g. `match 'abc#a*'` -> bc"
 100                 );
 101                 return 1;
 102         }
 103
 104         for (i = 1; i < argc; ++i) {
 105                 size_t off;
 106                 scan_t scan;
 107
 108                 printf("'%s': ", argv[i]);
 109
 110                 string = strdup(argv[i]);
 111                 off = strcspn(string, "#%");
 112                 if (!off) {
 113                         printf("invalid format\n");
 114                         free(string);
 115                         continue;
 116                 }
 117                 op = string + off;
 118                 scan = pick_scan(op[0], op[1], &match_at_left);
 119                 pattern = op + 1;
 120                 if (op[0] == op[1])
 121                         op[1] = '\0', ++pattern;
 122                 op[0] = '\0';
 123
 124                 loc = scan(string, pattern, match_at_left);
 125
 126                 if (match_at_left) {
 127                         printf("'%s'\n", loc);
 128                 } else {
 129                         *loc = '\0';
 130                         printf("'%s'\n", string);
 131                 }
 132
 133                 free(string);
 134         }
 135
 136         return 0;
 137 }
 138 #endif