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/* setvbuf( FILE *, char *, int, size_t )
This file is part of the Public Domain C Library (PDCLib).
Permission is granted to use, modify, and / or redistribute at will.
*/
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#ifndef REGTEST
#ifndef __STDC_NO_THREADS__
#include <threads.h>
#endif
int setvbuf( struct _PDCLIB_file_t * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mode, size_t size )
{
switch ( mode )
{
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.
*/
_PDCLIB_LOCK( stream->mtx );
break;
case _IOFBF:
case _IOLBF:
if ( size > INT_MAX || size == 0 )
{
/* PDCLib only supports buffers up to INT_MAX in size. A size
of zero doesn't make sense.
*/
return -1;
}
if ( buf != NULL )
{
/* User provided buffer. Deallocate existing buffer, and mark
the stream so that fclose() does not try to deallocate the
user's buffer.
*/
if ( stream->status & _PDCLIB_FREEBUFFER )
{
free( stream->buffer );
}
stream->status &= ~_PDCLIB_FREEBUFFER;
}
else
{
/* User requested buffer size, but leaves it to library to
allocate the buffer.
*/
/* 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.
*/
_PDCLIB_LOCK( stream->mtx );
if ( ( stream->bufsize < size ) || ( stream->bufsize > ( size << 1 ) ) )
{
/* Buffer too small, or much too large - allocate. */
if ( ( buf = ( char * ) malloc( size ) ) == NULL )
{
/* Out of memory error. */
_PDCLIB_UNLOCK( stream->mtx );
return -1;
}
if ( stream->status & _PDCLIB_FREEBUFFER )
{
free( stream->buffer );
}
/* This buffer must be free()d on fclose() */
stream->status |= _PDCLIB_FREEBUFFER;
}
}
stream->buffer = buf;
stream->bufsize = size;
break;
default:
/* If mode is something else than _IOFBF, _IOLBF or _IONBF -> exit */
return -1;
}
/* Deleting current buffer mode */
stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
/* Set user-defined mode */
stream->status |= mode;
_PDCLIB_UNLOCK( stream->mtx );
return 0;
}
#endif
#ifdef TEST
#include "_PDCLIB_test.h"
#include <errno.h>
#define BUFFERSIZE 500
int main( void )
{
#ifndef REGTEST
char buffer[ BUFFERSIZE ];
FILE * fh;
/* full buffered, user-supplied buffer */
TESTCASE( ( fh = tmpfile() ) != NULL );
TESTCASE( setvbuf( fh, buffer, _IOFBF, BUFFERSIZE ) == 0 );
TESTCASE( fh->buffer == buffer );
TESTCASE( fh->bufsize == BUFFERSIZE );
TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOFBF );
TESTCASE( fclose( fh ) == 0 );
/* line buffered, lib-supplied buffer */
TESTCASE( ( fh = tmpfile() ) != NULL );
TESTCASE( setvbuf( fh, NULL, _IOLBF, BUFFERSIZE ) == 0 );
TESTCASE( fh->buffer != NULL );
TESTCASE( fh->bufsize == BUFFERSIZE );
TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOLBF );
TESTCASE( fclose( fh ) == 0 );
/* not buffered, user-supplied buffer */
TESTCASE( ( fh = tmpfile() ) != NULL );
TESTCASE( setvbuf( fh, buffer, _IONBF, BUFFERSIZE ) == 0 );
TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IONBF );
TESTCASE( fclose( fh ) == 0 );
#else
puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
#endif
return TEST_RESULTS;
}
#endif
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