src/filename_expand.cxx

   1 //
   2 // "$Id: filename_expand.cxx 7903 2010-11-28 21:06:39Z matt $"
   3 //
   4 // Filename expansion routines for the Fast Light Tool Kit (FLTK).
   5 //
   6 // Copyright 1998-2010 by Bill Spitzak and others.
   7 //
   8 // This library is free software; you can redistribute it and/or
   9 // modify it under the terms of the GNU Library General Public
  10 // License as published by the Free Software Foundation; either
  11 // version 2 of the License, or (at your option) any later version.
  12 //
  13 // This library is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 // Library General Public License for more details.
  17 //
  18 // You should have received a copy of the GNU Library General Public
  19 // License along with this library; if not, write to the Free Software
  20 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21 // USA.
  22 //
  23 // Please report all bugs and problems on the following page:
  24 //
  25 //     http://www.fltk.org/str.php
  26 //
  27
  28 /* expand a file name by substuting environment variables and
  29    home directories.  Returns true if any changes were made.
  30    to & from may be the same buffer.
  31 */
  32
  33 #include <FL/filename.H>
  34 #include <FL/fl_utf8.h>
  35 #include <stdlib.h>
  36 #include "flstring.h"
  37 #if defined(WIN32) && !defined(__CYGWIN__)
  38 #include <windows.h>
  39 #else
  40 # include <unistd.h>
  41 # include <pwd.h>
  42 #endif
  43
  44 #if defined(WIN32) || defined(__EMX__) && !defined(__CYGWIN__)
  45 static inline int isdirsep(char c) {return c=='/' || c=='\\';}
  46 #else
  47 #define isdirsep(c) ((c)=='/')
  48 #endif
  49
  50 /** Expands a filename containing shell variables and tilde (~).
  51     Currently handles these variants:
  52     \code
  53     "~username"               // if 'username' does not exist, result will be unchanged
  54     "~/file"
  55     "$VARNAME"                // does NOT handle ${VARNAME}
  56     \endcode
  57
  58     \b Examples:
  59     \code
  60     #include <FL/filename.H>
  61     [..]
  62     putenv("TMPDIR=/var/tmp");
  63     fl_filename_expand(out, sizeof(out), "~fred/.cshrc");     // out="/usr/fred/.cshrc"
  64     fl_filename_expand(out, sizeof(out), "~/.cshrc");         // out="/usr/<yourname>/.cshrc"
  65     fl_filename_expand(out, sizeof(out), "$TMPDIR/foo.txt");  // out="/var/tmp/foo.txt"
  66     \endcode
  67     \param[out] to resulting expanded filename
  68     \param[in]  tolen size of the expanded filename buffer
  69     \param[in]  from filename containing shell variables
  70     \return 0 if no change, non zero otherwise
  71  */
  72 int fl_filename_expand(char *to,int tolen, const char *from) {
  73
  74   char *temp = new char[tolen];
  75   strlcpy(temp,from, tolen);
  76   char *start = temp;
  77   char *end = temp+strlen(temp);
  78
  79   int ret = 0;
  80
  81   for (char *a=temp; a<end; ) { // for each slash component
  82     char *e; for (e=a; e<end && !isdirsep(*e); e++); // find next slash
  83     const char *value = 0; // this will point at substitute value
  84     switch (*a) {
  85     case '~':   // a home directory name
  86       if (e <= a+1) {   // current user's directory
  87         value = fl_getenv("HOME");
  88 #ifndef WIN32
  89       } else {  // another user's directory
  90         struct passwd *pwd;
  91         char t = *e; *(char *)e = 0;
  92         pwd = getpwnam(a+1);
  93         *(char *)e = t;
  94             if (pwd) value = pwd->pw_dir;
  95 #endif
  96       }
  97       break;
  98     case '$':           /* an environment variable */
  99       {char t = *e; *(char *)e = 0; value = fl_getenv(a+1); *(char *)e = t;}
 100       break;
 101     }
 102     if (value) {
 103       // substitutions that start with slash delete everything before them:
 104       if (isdirsep(value[0])) start = a;
 105 #if defined(WIN32) || defined(__EMX__) && !defined(__CYGWIN__)
 106       // also if it starts with "A:"
 107       if (value[0] && value[1]==':') start = a;
 108 #endif
 109       int t = strlen(value); if (isdirsep(value[t-1])) t--;
 110       if ((end+1-e+t) >= tolen) end += tolen - (end+1-e+t);
 111       memmove(a+t, e, end+1-e);
 112       end = a+t+(end-e);
 113       *end = '\0';
 114       memcpy(a, value, t);
 115       ret++;
 116     } else {
 117       a = e+1;
 118 #if defined(WIN32) || defined(__EMX__) && !defined(__CYGWIN__)
 119       if (*e == '\\') {*e = '/'; ret++;} // ha ha!
 120 #endif
 121     }
 122   }
 123
 124   strlcpy(to, start, tolen);
 125
 126   delete[] temp;
 127
 128   return ret;
 129 }
 130
 131
 132 //
 133 // End of "$Id: filename_expand.cxx 7903 2010-11-28 21:06:39Z matt $".
 134 //