basename.c

   1 /*
   2     Copyright © 2013 Alastair Stuart
   3
   4     This program is open source software: you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation, either version 3 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12     GNU General Public License for more details.
  13 */
  14
  15 #include <stdio.h>
  16 #include <string.h>
  17
  18 #define VERSION "0.01"
  19
  20 int main(int argc, char* argv[])
  21 {
  22     // flag parsing
  23     int arg = 0;
  24     for (arg = 1; arg < argc; arg++)
  25     {
  26         if (strcmp("--help", argv[arg]) == 0 || strcmp("-h", argv[arg]) == 0) {
  27             printf("Usage: %s [name] [suffix]\n", argv[0]);
  28             printf("\n"
  29                    "    --help              Print this message.\n"
  30                    "    --version           Show version info.\n");
  31             return 0;
  32         } else if (strcmp("--version", argv[arg]) == 0 || strcmp("-v", argv[arg]) == 0) {
  33             printf("basename (mutos) v"VERSION"\n");
  34             return 0;
  35         } else if (strcmp(argv[arg], "--") == 0) {
  36             arg++;
  37             break;
  38         } else {
  39             break;
  40         }
  41     }
  42
  43     if ((argc - arg) == 0) {
  44         fprintf(stderr, "%s: missing operand\n"
  45                         "Run '%s --help' for usage.\n",
  46                         argv[0], argv[0]);
  47         return 1;
  48     } else if ((argc - arg) > 2) {
  49         fprintf(stderr, "%s: too many arguments\n",
  50                          argv[0]);
  51         return 1;
  52     }
  53
  54     char* name   = argv[arg];
  55     char* suffix = NULL;
  56
  57     // check if string consists entirely of slash characters
  58     for (size_t i = 0; i < strlen(name); i++)
  59     {
  60         if (name[i] != '/') {
  61             break;
  62         }
  63
  64         if (name[i] == '/' && i == strlen(name) - 1) {
  65             printf("/\n");
  66             return 0;
  67         }
  68     }
  69
  70     // remove any trailing slashes
  71     for (size_t i = strlen(name) - 1; ; i--)
  72     {
  73         if (name[i] == '/') {
  74             name[i] = '\0';
  75         } else {
  76             // if there's no more slashes
  77             break;
  78         }
  79
  80         // reached the beginning of the string
  81         if (i == 0) {
  82             break;
  83         }
  84     }
  85
  86     // trim suffix (if there is one)
  87     if ((argc - arg) == 2) {
  88         suffix = argv[arg + 1];
  89
  90         for (size_t i = strlen(name), j = strlen(suffix); ; i--, j--)
  91         {
  92             if (name[i - 1] == suffix[j - 1]) {
  93                 name[i - 1] = '\0';
  94             } else {
  95                 break;
  96             }
  97         }
  98     }
  99
 100     // find the first slash
 101     size_t start = 0;
 102     for (size_t i = strlen(name) - 1; ; i--)
 103     {
 104         if (name[i] == '/') {
 105             start = i + 1;
 106             break;
 107         }
 108
 109         // reached the beginning of the string
 110         if (i == 0) {
 111             start = i;
 112             break;
 113         }
 114     }
 115
 116     // if suffix deleted the entire basename,
 117     // print the whole basename instead of
 118     // nothing
 119     if (strlen(name+start) == 0) {
 120         printf("%s", suffix);
 121     } else {
 122         printf("%s", name+start);
 123     }
 124     printf("\n");
 125
 126     return 0;
 127 }