git.gag.com Git - fw/pdclib/blob - functions/_PDCLIB/filemode.c

   1 /* $Id$ */
   2
   3 /* _PDCLIB_filemode( const char * )
   4
   5    This file is part of the Public Domain C Library (PDCLib).
   6    Permission is granted to use, modify, and / or redistribute at will.
   7 */
   8
   9 #include <stdio.h>
  10 #include <stddef.h>
  11
  12 /* Helper function that parses the C-style mode string passed to fopen() into
  13    the PDCLib flags FREAD, FWRITE, FAPPEND, FRW (read-write) and FBIN (binary
  14    mode).
  15 */
  16 unsigned int _PDCLIB_filemode( char const * const mode )
  17 {
  18     unsigned rc = 0;
  19     switch ( mode[0] )
  20     {
  21         case 'r':
  22             rc |= _PDCLIB_FREAD;
  23             break;
  24         case 'w':
  25             rc |= _PDCLIB_FWRITE;
  26             break;
  27         case 'a':
  28             rc |= _PDCLIB_FAPPEND | _PDCLIB_FWRITE;
  29             break;
  30         default:
  31             /* Other than read, write, or append - invalid */
  32             return 0;
  33     }
  34     for ( size_t i = 1; i < 4; ++i )
  35     {
  36         switch ( mode[i] )
  37         {
  38             case '+':
  39                 if ( rc & _PDCLIB_FRW ) return 0; /* Duplicates are invalid */
  40                 rc |= _PDCLIB_FRW;
  41                 break;
  42             case 'b':
  43                 if ( rc & _PDCLIB_FBIN ) return 0; /* Duplicates are invalid */
  44                 rc |= _PDCLIB_FBIN;
  45                 break;
  46             case '\0':
  47                 /* End of mode */
  48                 return rc;
  49             default:
  50                 /* Other than read/write or binary - invalid. */
  51                 return 0;
  52         }
  53     }
  54     /* Longer than three chars - invalid. */
  55     return 0;
  56 }
  57
  58 #ifdef TEST
  59 #include <_PDCLIB_test.h>
  60
  61 int main( void )
  62 {
  63     TESTCASE( _PDCLIB_filemode( "r" ) == _PDCLIB_FREAD );
  64     TESTCASE( _PDCLIB_filemode( "w" ) == _PDCLIB_FWRITE );
  65     TESTCASE( _PDCLIB_filemode( "a" ) == ( _PDCLIB_FAPPEND | _PDCLIB_FWRITE ) );
  66     TESTCASE( _PDCLIB_filemode( "r+" ) == ( _PDCLIB_FREAD | _PDCLIB_FRW ) );
  67     TESTCASE( _PDCLIB_filemode( "w+" ) == ( _PDCLIB_FWRITE | _PDCLIB_FRW ) );
  68     TESTCASE( _PDCLIB_filemode( "a+" ) == ( _PDCLIB_FAPPEND | _PDCLIB_FWRITE | _PDCLIB_FRW ) );
  69     TESTCASE( _PDCLIB_filemode( "rb" ) == ( _PDCLIB_FREAD | _PDCLIB_FBIN ) );
  70     TESTCASE( _PDCLIB_filemode( "wb" ) == ( _PDCLIB_FWRITE | _PDCLIB_FBIN ) );
  71     TESTCASE( _PDCLIB_filemode( "ab" ) == ( _PDCLIB_FAPPEND | _PDCLIB_FWRITE | _PDCLIB_FBIN ) );
  72     TESTCASE( _PDCLIB_filemode( "r+b" ) == ( _PDCLIB_FREAD | _PDCLIB_FRW | _PDCLIB_FBIN ) );
  73     TESTCASE( _PDCLIB_filemode( "w+b" ) == ( _PDCLIB_FWRITE | _PDCLIB_FRW | _PDCLIB_FBIN ) );
  74     TESTCASE( _PDCLIB_filemode( "a+b" ) == ( _PDCLIB_FAPPEND | _PDCLIB_FWRITE | _PDCLIB_FRW | _PDCLIB_FBIN ) );
  75     TESTCASE( _PDCLIB_filemode( "rb+" ) == ( _PDCLIB_FREAD | _PDCLIB_FRW | _PDCLIB_FBIN ) );
  76     TESTCASE( _PDCLIB_filemode( "wb+" ) == ( _PDCLIB_FWRITE | _PDCLIB_FRW | _PDCLIB_FBIN ) );
  77     TESTCASE( _PDCLIB_filemode( "ab+" ) == ( _PDCLIB_FAPPEND | _PDCLIB_FWRITE | _PDCLIB_FRW | _PDCLIB_FBIN ) );
  78     TESTCASE( _PDCLIB_filemode( "x" ) == 0 );
  79     TESTCASE( _PDCLIB_filemode( "r++" ) == 0 );
  80     TESTCASE( _PDCLIB_filemode( "wbb" ) == 0 );
  81     TESTCASE( _PDCLIB_filemode( "a+bx" ) == 0 );
  82     return TEST_RESULTS;
  83 }
  84
  85 #endif
  86