pd.if.org Git - pdclib/blob - functions/_PDCLIB/filemode.c

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