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 /* global debugging flag */
  44 int debug=0;
  45
  46 /*******************
  47         Code
  48 ********************/
  49
  50 /**
  51  * add_to_library_path - Adds a directory path to the search path
  52  * @path: the directory path
  53  * @strip: flag to strip the upper level
  54  *
  55  * Adds @path to the list of searchable paths for path_fopen(),
  56  * optionally stripping the upper level if @strip is set.
  57  * The last part of the path is stripped before being stored,
  58  * and duplication is avoided.
  59  */
  60 void add_to_library_path(char * path, int strip)
  61 {
  62         int n;
  63         char * ptr;
  64
  65         /* if path starts with ~, pre-prend $HOME */
  66         if(*path == '~')
  67         {
  68                 char * new;
  69                 char * home;
  70
  71                 if((home=getenv("HOME")) == NULL)
  72                         return;
  73
  74                 if((new=malloc(strlen(home) + strlen(path) + 2)) == NULL)
  75                         return;
  76
  77                 strcpy(new, home);
  78                 strcat(new, "/");
  79                 strcat(new, path + 1);
  80
  81                 path=new;
  82         }
  83         else
  84         {
  85                 /* just duplicate */
  86                 path=strdup(path);
  87         }
  88
  89         /* if no directory path remains, abort */
  90         if((ptr=strrchr(path, '/')) == NULL)
  91         {
  92                 free(path);
  93                 return;
  94         }
  95
  96         /* strip the filename part */
  97         if(strip) *ptr='\0';
  98
  99         /* now try to find if that path is already stored */
 100         for(n=0;n < n_library_paths;n++)
 101         {
 102                 if(strcmp(path, library_path[n]) == 0)
 103                 {
 104                         /* found; free and return */
 105                         free(path);
 106                         return;
 107                 }
 108         }
 109
 110         /* add room for the new path */
 111         n_library_paths++;
 112         library_path=(char **)realloc(library_path,
 113                 n_library_paths * sizeof(char *));
 114
 115         /* store */
 116         library_path[n_library_paths - 1]=path;
 117 }
 118
 119
 120 /**
 121  * path_fopen - Opens a file, optionally searching in a path list
 122  * @filename: the file name
 123  * @mode: the file mode
 124  *
 125  * Opens a file. If the file is found as is, it's opened;
 126  * otherwise, the full list of directory paths maintained by
 127  * add_to_library_path() is searched until it's found or the
 128  * end of the list is reached. Whenever a file
 129  * is successfully opened, its path is also stored.
 130  */
 131 FILE * path_fopen(char * filename, char * mode)
 132 {
 133         int n;
 134         FILE * f=NULL;
 135
 136         /* try first here */
 137         if((f=fopen(filename, mode)) != NULL)
 138         {
 139                 strncpy(located_file, filename, sizeof(located_file));
 140                 located_file[sizeof(located_file) - 1]='\0';
 141
 142                 add_to_library_path(filename, 1);
 143                 return(f);
 144         }
 145
 146         /* couldn't open; try concatenating all stored paths */
 147         for(n=n_library_paths - 1;n >= 0;n--)
 148         {
 149                 snprintf(located_file, sizeof(located_file), "%s/%s",
 150                         library_path[n], filename);
 151                 located_file[sizeof(located_file) - 1]='\0';
 152
 153                 if((f=fopen(located_file, mode)) != NULL)
 154                 {
 155                         add_to_library_path(located_file, 1);
 156                         break;
 157                 }
 158         }
 159
 160         return(f);
 161 }
 162
 163
 164 /**
 165  * locate_file - Locates a file inside the path
 166  * @filename: the file to be located
 167  *
 168  * Locates a file inside the library path maintained by path_fopen()
 169  * and add_library_path(). If the file is found, a pointer to a static
 170  * buffer containing the real path of the file is returned, or
 171  * NULL otherwise.
 172  */
 173 char * locate_file(char * filename)
 174 {
 175         FILE * f;
 176
 177         if((f=path_fopen(filename, "r")) == NULL)
 178                 return(NULL);
 179
 180         fclose(f);
 181         return(located_file);
 182 }