support.c

   1 /*
   2
   3     Ann Hell Ex Machina - Music Software
   4     Copyright (C) 2003/2005 Angel Ortega <angel@triptico.com>
   5
   6     support.c - Miscellaneous support functions
   7
   8     This program is free software; you can redistribute it and/or
   9     modify it under the terms of the GNU General Public License
  10     as published by the Free Software Foundation; either version 2
  11     of the License, or (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21
  22     http://www.triptico.com
  23
  24 */
  25
  26 #include "config.h"
  27
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31
  32 #include "annhell.h"
  33
  34 /*******************
  35         Data
  36 ********************/
  37
  38 static char ** library_path=NULL;
  39 static int n_library_paths=0;
  40
  41 static char located_file[2048];
  42
  43 /*******************
  44         Code
  45 ********************/
  46
  47 /**
  48  * add_to_library_path - Adds a directory path to the search path
  49  * @path: the directory path
  50  * @strip: flag to strip the upper level
  51  *
  52  * Adds @path to the list of searchable paths for path_fopen(),
  53  * optionally stripping the upper level if @strip is set.
  54  * The last part of the path is stripped before being stored,
  55  * and duplication is avoided.
  56  */
  57 void add_to_library_path(char * path, int strip)
  58 {
  59         int n;
  60         char * ptr;
  61
  62         /* if path starts with ~, pre-prend $HOME */
  63         if(*path == '~')
  64         {
  65                 char * new;
  66                 char * home;
  67
  68                 if((home=getenv("HOME")) == NULL)
  69                         return;
  70
  71                 if((new=malloc(strlen(home) + strlen(path) + 2)) == NULL)
  72                         return;
  73
  74                 strcpy(new, home);
  75                 strcat(new, "/");
  76                 strcat(new, path + 1);
  77
  78                 path=new;
  79         }
  80         else
  81         {
  82                 /* just duplicate */
  83                 path=strdup(path);
  84         }
  85
  86         /* if no directory path remains, abort */
  87         if((ptr=strrchr(path, '/')) == NULL)
  88         {
  89                 free(path);
  90                 return;
  91         }
  92
  93         /* strip the filename part */
  94         if(strip) *ptr='\0';
  95
  96         /* now try to find if that path is already stored */
  97         for(n=0;n < n_library_paths;n++)
  98         {
  99                 if(strcmp(path, library_path[n]) == 0)
 100                 {
 101                         /* found; free and return */
 102                         free(path);
 103                         return;
 104                 }
 105         }
 106
 107         /* add room for the new path */
 108         n_library_paths++;
 109         library_path=(char **)realloc(library_path,
 110                 n_library_paths * sizeof(char *));
 111
 112         /* store */
 113         library_path[n_library_paths - 1]=path;
 114 }
 115
 116
 117 /**
 118  * path_fopen - Opens a file, optionally searching in a path list
 119  * @filename: the file name
 120  * @mode: the file mode
 121  *
 122  * Opens a file. If the file is found as is, it's opened;
 123  * otherwise, the full list of directory paths maintained by
 124  * add_to_library_path() is searched until it's found or the
 125  * end of the list is reached. Whenever a file
 126  * is successfully opened, its path is also stored.
 127  */
 128 FILE * path_fopen(char * filename, char * mode)
 129 {
 130         int n;
 131         FILE * f=NULL;
 132
 133         /* try first here */
 134         if((f=fopen(filename, mode)) != NULL)
 135         {
 136                 strncpy(located_file, filename, sizeof(located_file));
 137                 located_file[sizeof(located_file) - 1]='\0';
 138
 139                 add_to_library_path(filename, 1);
 140                 return(f);
 141         }
 142
 143         /* couldn't open; try concatenating all stored paths */
 144         for(n=n_library_paths - 1;n >= 0;n--)
 145         {
 146                 snprintf(located_file, sizeof(located_file), "%s/%s",
 147                         library_path[n], filename);
 148                 located_file[sizeof(located_file) - 1]='\0';
 149
 150                 if((f=fopen(located_file, mode)) != NULL)
 151                 {
 152                         add_to_library_path(located_file, 1);
 153                         break;
 154                 }
 155         }
 156
 157         return(f);
 158 }
 159
 160
 161 /**
 162  * locate_file - Locates a file inside the path
 163  * @filename: the file to be located
 164  *
 165  * Locates a file inside the library path maintained by path_fopen()
 166  * and add_library_path(). If the file is found, a pointer to a static
 167  * buffer containing the real path of the file is returned, or
 168  * NULL otherwise.
 169  */
 170 char * locate_file(char * filename)
 171 {
 172         FILE * f;
 173
 174         if((f=path_fopen(filename, "r")) == NULL)
 175                 return(NULL);
 176
 177         fclose(f);
 178         return(located_file);
 179 }