#include <stdio.h>
#include <stdlib.h>
+#include <limits.h>
#ifndef REGTEST
int setvbuf( struct _PDCLIB_file_t * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mode, size_t size )
{
- /* 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 ) ) ||
- ! ( stream->status & _PDCLIB_LIBBUFFER ) )
- {
- return -1;
- }
- if ( mode == _IONBF )
- {
- /* When unbuffered I/O is requested, we don't need a buffer. */
- buf = NULL;
- size = 0;
- }
- else
- {
- /* 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 ( size < 256 )
- {
- buf = NULL; /* do not use too-small user buffer */
- size = 256;
- }
- }
- /* If a suitable buffer is provided by user... */
- if ( buf != NULL )
+ switch ( mode )
{
- /* ...do not free it in library functions like fclose(), freopen(). */
- stream->status &= ~_PDCLIB_LIBBUFFER;
+ case _IONBF:
+ /* When unbuffered I/O is requested, we keep the buffer anyway, as
+ we don't want to e.g. flush the stream for every character of a
+ stream being printed.
+ */
+ break;
+ case _IOFBF:
+ case _IOLBF:
+ if ( size > INT_MAX || size == NULL )
+ {
+ /* PDCLib only supports buffers up to INT_MAX in size. A size
+ of zero doesn't make sense.
+ */
+ return -1;
+ }
+ if ( buf == NULL )
+ {
+ /* User requested buffer size, but leaves it to library to
+ allocate the buffer.
+ */
+ if ( ( stream->bufsize < size ) || ( stream->bufsize > ( size << 1 ) ) )
+ {
+ /* If current buffer is big enough for requested size, but
+ not over twice as big (and wasting memory space), we use
+ the current buffer (i.e., do nothing), to save the
+ malloc() / free() overhead.
+ */
+ /* Free the buffer allocated by fopen(), and allocate a new
+ one.
+ */
+ if ( ( buf = (char *) malloc( size ) ) == NULL )
+ {
+ /* Out of memory error. */
+ return -1;
+ }
+ }
+ }
+ else
+ {
+ /* User provided buffer -> set flag to not free() the buffer
+ on fclose().
+ */
+ stream->status &= ~ _PDCLIB_LIBBUFFER;
+ }
+ free( stream->buffer );
+ stream->buffer = buf;
+ stream->bufsize = size;
+ break;
+ default:
+ /* If mode is something else than _IOFBF, _IOLBF or _IONBF -> exit */
+ return -1;
}
- /* 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. */
+ /* Deleting current buffer mode */
stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
+ /* Set user-defined mode */
stream->status |= mode;
- stream->bufsize = size;
- stream->status &= ~_PDCLIB_VIRGINSTR;
return 0;
-#endif
}
#endif
#ifdef TEST
#include <_PDCLIB_test.h>
+#include <errno.h>
+
#define BUFFERSIZE 500
int main( void )
#ifndef REGTEST
char const * const filename = "testfile";
char buffer[ BUFFERSIZE ];
- struct _PDCLIB_file_t * fh;
+ FILE * fh;
+ remove( filename );
/* 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 );
+ TESTCASE( remove( filename ) == 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 );
+ TESTCASE( remove( filename ) == 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 );
+ TESTCASE( remove( filename ) == 0 );
#else
puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
#endif
}
#endif
+
projects / pdclib / blobdiff