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