Justin C. Miller
95a35cd0bf
Moving libc from its separate repo into this one, minor resulting build fixes, and a hacky way to add -I for libc headers in builds.
55 lines
1.5 KiB
C
55 lines
1.5 KiB
C
/* _PDCLIB_filemode( const char * )
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This file is part of the Public Domain C Library (PDCLib).
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Permission is granted to use, modify, and / or redistribute at will.
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*/
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#include <stddef.h>
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/* Helper function that parses the C-style mode string passed to fopen() into
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the PDCLib flags FREAD, FWRITE, FAPPEND, FRW (read-write) and FBIN (binary
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mode).
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*/
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unsigned int _PDCLIB_filemode( const char * const mode )
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{
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unsigned rc = 0;
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size_t i;
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switch ( mode[0] )
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{
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case 'r':
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rc |= _PDCLIB_FREAD;
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break;
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case 'w':
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rc |= _PDCLIB_FWRITE;
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break;
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case 'a':
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rc |= _PDCLIB_FAPPEND | _PDCLIB_FWRITE;
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break;
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default:
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/* Other than read, write, or append - invalid */
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return 0;
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}
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for ( i = 1; i < 4; ++i )
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{
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switch ( mode[i] )
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{
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case '+':
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if ( rc & _PDCLIB_FRW ) return 0; /* Duplicates are invalid */
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rc |= _PDCLIB_FRW;
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break;
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case 'b':
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if ( rc & _PDCLIB_FBIN ) return 0; /* Duplicates are invalid */
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rc |= _PDCLIB_FBIN;
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break;
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case '\0':
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/* End of mode */
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return rc;
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default:
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/* Other than read/write or binary - invalid. */
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return 0;
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}
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}
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/* Longer than three chars - invalid. */
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return 0;
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}
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