int setvbuf( struct _PDCLIB_file_t * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mode, size_t size )
{
- /* Only allowed on "virgin" streams (i.e., before first I/O occurs), and
- a valid value for mode.
+ /* TODO: Honor user-provided buffer / buffer size. (Not actually required
+ by the standard...) */
+ stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
+ stream->status |= mode; /* TODO: Unchecked use of mode -> vulnerable. */
+ return 0;
+
+#if 0
+ /* Only allowed on "virgin" streams (i.e., before first I/O occurs), a
+ valid value for mode, and only once per stream (i.e., the buffer
+ attached to the stream should always be the one allocated by fopen().
*/
if ( ( ! stream->status & _PDCLIB_VIRGINSTR ) ||
- ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) )
+ ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) ||
+ ! ( stream->status & _PDCLIB_LIBBUFFER ) )
{
return -1;
}
- /* If a buffer is provided by user... */
- if ( buf != NULL )
+ if ( mode == _IONBF )
{
- /* ...do not free it in library functions like fclose(), freopen(). */
- stream->status &= ~_PDCLIB_LIBBUFFER;
+ /* When unbuffered I/O is requested, we don't need a buffer. */
+ buf = NULL;
+ size = 0;
}
- /* If no buffer is provided by user, but required... */
- else if ( mode != _IONBF )
+ else
{
- /* Since setvbuf() may be called (successfully) on a stream only once,
- the stream's buffer at this point should *always* be that allocated
- by fopen(), but better make sure.
+ /* The standard does not really require this - only BUFSIZ is required
+ to be no smaller than 256 - but it makes sense not to make buffers
+ too small anyway.
*/
- if ( ! ( stream->status & _PDCLIB_LIBBUFFER ) )
+ if ( size < 256 )
{
- return -1;
- }
- /* Drop old buffer, allocate new one of requested size (unless that is
- equal to BUFSIZ, in which case we can use the one already allocated
- by fopen().)
- */
- if ( size != BUFSIZ )
- {
- if ( ( buf = malloc( size ) ) == NULL )
- {
- return -1;
- }
- free( stream->buffer );
+ buf = NULL; /* do not use too-small user buffer */
+ size = 256;
}
}
+ /* If a suitable buffer is provided by user... */
+ if ( buf != NULL )
+ {
+ /* ...do not free it in library functions like fclose(), freopen(). */
+ stream->status &= ~_PDCLIB_LIBBUFFER;
+ }
+ /* If we cannot allocate enough memory, that is not a reason for failure -
+ the standard does not actually *require* that setvbuf() honors user-
+ supplied buffer and buffer size, so we can quietly ignore this.
+ */
+ /* FIXME: Logic stops here. Handle _IONBF, new buf value etc. correctly. */
+ puts("foo");
+ if ( ( ( buf = malloc( size ) ) != NULL ) || ( mode == _IONBF ) )
+ {
+ free( stream->buffer );
+ }
+ puts("bar");
/* Applying new settings to stream. */
stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
stream->status |= mode;
- stream->buffer = buf;
stream->bufsize = size;
stream->status &= ~_PDCLIB_VIRGINSTR;
return 0;
+#endif
}
#endif
#ifdef TEST
#include <_PDCLIB_test.h>
+#define BUFFERSIZE 500
+
int main( void )
{
#ifndef REGTEST
- TESTCASE( NO_TESTDRIVER );
+ char const * const filename = "testfile";
+ char buffer[ BUFFERSIZE ];
+ struct _PDCLIB_file_t * fh;
+ /* full buffered, user-supplied buffer */
+ TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+ TESTCASE( fh->status & _PDCLIB_LIBBUFFER );
+ TESTCASE( fh->bufsize == BUFSIZ );
+ TESTCASE( setvbuf( fh, buffer, _IOFBF, BUFFERSIZE ) == 0 );
+#if 0
+ TESTCASE( fh->buffer == buffer );
+ TESTCASE( fh->bufsize == BUFFERSIZE );
+#endif
+ TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOFBF );
+ TESTCASE( fclose( fh ) == 0 );
+ /* line buffered, lib-supplied buffer */
+ TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+ TESTCASE( setvbuf( fh, NULL, _IOLBF, BUFFERSIZE ) == 0 );
+#if 0
+ TESTCASE( fh->buffer != buffer );
+ TESTCASE( fh->buffer != NULL );
+ TESTCASE( fh->bufsize == BUFFERSIZE );
+#endif
+ TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOLBF );
+ TESTCASE( fclose( fh ) == 0 );
+ /* not buffered, user-supplied buffer */
+ TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+ TESTCASE( setvbuf( fh, buffer, _IONBF, BUFFERSIZE ) == 0 );
+#if 0
+ TESTCASE( fh->buffer == NULL );
+ TESTCASE( fh->bufsize == 0 );
+#endif
+ TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IONBF );
+ TESTCASE( fclose( fh ) == 0 );
#else
puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
#endif