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 GPLv2 or later, see file LICENSE in this source tree.
   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         while (1) {
  35                 int match;
  36
  37                 c = *loc;
  38                 if (match_at_left) {
  39                         *loc = '\0';
  40                         match = pmatch(pattern, string);
  41                         *loc = c;
  42                 } else {
  43                         match = pmatch(pattern, loc);
  44                 }
  45                 if (match)
  46                         return loc;
  47                 if (!c)
  48                         return NULL;
  49                 loc++;
  50         }
  51 }
  52
  53 char *scanright(char *string, char *pattern, bool match_at_left)
  54 {
  55         char c;
  56         char *loc = string + strlen(string);
  57
  58         while (loc >= string) {
  59                 int match;
  60
  61                 c = *loc;
  62                 if (match_at_left) {
  63                         *loc = '\0';
  64                         match = pmatch(pattern, string);
  65                         *loc = c;
  66                 } else {
  67                         match = pmatch(pattern, loc);
  68                 }
  69                 if (match)
  70                         return loc;
  71                 loc--;
  72         }
  73
  74         return NULL;
  75 }
  76
  77 #ifdef STANDALONE
  78 int main(int argc, char *argv[])
  79 {
  80         char *string;
  81         char *op;
  82         char *pattern;
  83         bool match_at_left;
  84         char *loc;
  85
  86         int i;
  87
  88         if (argc == 1) {
  89                 puts(
  90                         "Usage: match <test> [test...]\n\n"
  91                         "Where a <test> is the form: <string><op><match>\n"
  92                         "This is to test the shell ${var#val} expression type.\n\n"
  93                         "e.g. `match 'abc#a*'` -> bc"
  94                 );
  95                 return 1;
  96         }
  97
  98         for (i = 1; i < argc; ++i) {
  99                 size_t off;
 100                 scan_t scan;
 101
 102                 printf("'%s': ", argv[i]);
 103
 104                 string = strdup(argv[i]);
 105                 off = strcspn(string, "#%");
 106                 if (!off) {
 107                         printf("invalid format\n");
 108                         free(string);
 109                         continue;
 110                 }
 111                 op = string + off;
 112                 scan = pick_scan(op[0], op[1], &match_at_left);
 113                 pattern = op + 1;
 114                 if (op[0] == op[1])
 115                         op[1] = '\0', ++pattern;
 116                 op[0] = '\0';
 117
 118                 loc = scan(string, pattern, match_at_left);
 119
 120                 if (match_at_left) {
 121                         printf("'%s'\n", loc);
 122                 } else {
 123                         *loc = '\0';
 124                         printf("'%s'\n", string);
 125                 }
 126
 127                 free(string);
 128         }
 129
 130         return 0;
 131 }
 132 #endif