*/
#include <stdio.h>
+#include <stdint.h>
#include <limits.h>
+#include <errno.h>
#ifndef REGTEST
+#include <_PDCLIB_io.h>
-long int ftell( struct _PDCLIB_file_t * stream )
+long int _PDCLIB_ftell_unlocked( FILE * stream )
{
- /* ftell() must take into account:
- - the actual *physical* offset of the file, i.e. the offset as recognized
- by the operating system (and stored in stream->pos.offset); and
- - any buffers held by PDCLib, which
- - in case of unwritten buffers, count in *addition* to the offset; or
- - in case of unprocessed pre-read buffers, count in *substraction* to
- the offset. (Remember to count ungetidx into this number.)
- Conveniently, the calculation ( ( bufend - bufidx ) + ungetidx ) results
- in just the right number in both cases:
- - in case of unwritten buffers, ( ( 0 - unwritten ) + 0 )
- i.e. unwritten bytes as negative number
- - in case of unprocessed pre-read, ( ( preread - processed ) + unget )
- i.e. unprocessed bytes as positive number.
- That is how the somewhat obscure return-value calculation works.
- */
- /* If offset is too large for return type, report error instead of wrong
- offset value.
- */
- /* TODO: Check what happens when ungetc() is called on a stream at offset 0 */
- if ( ( stream->pos.offset - stream->bufend ) > ( LONG_MAX - ( stream->bufidx - stream->ungetidx ) ) )
+ uint_fast64_t off64 = _PDCLIB_ftell64_unlocked( stream );
+
+ if ( off64 > LONG_MAX )
{
/* integer overflow */
- _PDCLIB_errno = _PDCLIB_ERANGE;
+ errno = ERANGE;
return -1;
}
- return (long int)( stream->pos.offset - ( ( (int)stream->bufend - (int)stream->bufidx ) + stream->ungetidx ) );
+ return off64;
+}
+
+long int ftell( FILE * stream )
+{
+ _PDCLIB_flockfile( stream );
+ long int off = _PDCLIB_ftell_unlocked( stream );
+ _PDCLIB_funlockfile( stream );
+ return off;
}
#endif
#ifdef TEST
#include <_PDCLIB_test.h>
-
#include <stdlib.h>
+#ifndef REGTEST
+#include <_PDCLIB_io.h>
+#endif
int main( void )
{
FILE * fh;
TESTCASE( ( fh = tmpfile() ) != NULL );
TESTCASE( setvbuf( fh, buffer, _IOLBF, 4 ) == 0 );
+ /* Testing ungetc() at offset 0 */
+ rewind( fh );
+ TESTCASE( ungetc( 'x', fh ) == 'x' );
+ TESTCASE( ftell( fh ) == -1l );
+ rewind( fh );
+ TESTCASE( ftell( fh ) == 0l );
+ /* Commence "normal" tests */
TESTCASE( fputc( '1', fh ) == '1' );
TESTCASE( fputc( '2', fh ) == '2' );
TESTCASE( fputc( '3', fh ) == '3' );