-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// Public Domain C Library - http://pdclib.sourceforge.net
-// This code is Public Domain. Use, modify, and redistribute at will.
-// ----------------------------------------------------------------------------
-
-int fseek( FILE * stream, long offset, int mode ) { /* TODO */ };
+/* $Id$ */
+
+/* fseek( FILE *, long offset, int )
+
+ 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>
+
+#ifndef REGTEST
+
+#include <_PDCLIB_glue.h>
+
+int fseek_unlocked( struct _PDCLIB_file_t * stream, long loffset, int whence )
+{
+ _PDCLIB_int64_t offset = loffset;
+ if ( stream->status & _PDCLIB_FWRITE )
+ {
+ if ( _PDCLIB_flushbuffer( stream ) == EOF )
+ {
+ return EOF;
+ }
+ }
+ stream->status &= ~ _PDCLIB_EOFFLAG;
+ if ( stream->status & _PDCLIB_FRW )
+ {
+ stream->status &= ~ ( _PDCLIB_FREAD | _PDCLIB_FWRITE );
+ }
+
+ if ( whence == SEEK_CUR )
+ {
+ whence = SEEK_SET;
+ offset += _PDCLIB_ftell64( stream );
+ }
+
+ return ( _PDCLIB_seek( stream, offset, whence ) != EOF ) ? 0 : EOF;
+}
+
+int fseek( struct _PDCLIB_file_t * stream, long loffset, int whence )
+{
+ flockfile( stream );
+ int r = fseek_unlocked( stream, loffset, whence );
+ funlockfile( stream );
+ return r;
+}
+
+#endif
+
+#ifdef TEST
+#include <_PDCLIB_test.h>
+#include <string.h>
+
+int main( void )
+{
+ FILE * fh;
+ TESTCASE( ( fh = tmpfile() ) != NULL );
+ TESTCASE( fwrite( teststring, 1, strlen( teststring ), fh ) == strlen( teststring ) );
+ /* General functionality */
+ TESTCASE( fseek( fh, -1, SEEK_END ) == 0 );
+ TESTCASE( (size_t)ftell( fh ) == strlen( teststring ) - 1 );
+ TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
+ TESTCASE( (size_t)ftell( fh ) == strlen( teststring ) );
+ TESTCASE( fseek( fh, 0, SEEK_SET ) == 0 );
+ TESTCASE( ftell( fh ) == 0 );
+ TESTCASE( fseek( fh, 5, SEEK_CUR ) == 0 );
+ TESTCASE( ftell( fh ) == 5 );
+ TESTCASE( fseek( fh, -3, SEEK_CUR ) == 0 );
+ TESTCASE( ftell( fh ) == 2 );
+ /* Checking behaviour around EOF */
+ TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
+ TESTCASE( ! feof( fh ) );
+ TESTCASE( fgetc( fh ) == EOF );
+ TESTCASE( feof( fh ) );
+ TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
+ TESTCASE( ! feof( fh ) );
+ /* Checking undo of ungetc() */
+ TESTCASE( fseek( fh, 0, SEEK_SET ) == 0 );
+ TESTCASE( fgetc( fh ) == teststring[0] );
+ TESTCASE( fgetc( fh ) == teststring[1] );
+ TESTCASE( fgetc( fh ) == teststring[2] );
+ TESTCASE( ftell( fh ) == 3 );
+ TESTCASE( ungetc( teststring[2], fh ) == teststring[2] );
+ TESTCASE( ftell( fh ) == 2 );
+ TESTCASE( fgetc( fh ) == teststring[2] );
+ TESTCASE( ftell( fh ) == 3 );
+ TESTCASE( ungetc( 'x', fh ) == 'x' );
+ TESTCASE( ftell( fh ) == 2 );
+ TESTCASE( fgetc( fh ) == 'x' );
+ TESTCASE( ungetc( 'x', fh ) == 'x' );
+ TESTCASE( ftell( fh ) == 2 );
+ TESTCASE( fseek( fh, 2, SEEK_SET ) == 0 );
+ TESTCASE( fgetc( fh ) == teststring[2] );
+ /* PDCLIB-7: Check that we handle the underlying file descriptor correctly
+ * in the SEEK_CUR case */
+ TESTCASE( fseek( fh, 10, SEEK_SET ) == 0 );
+ TESTCASE( ftell( fh ) == 10l );
+ TESTCASE( fseek( fh, 0, SEEK_CUR ) == 0 );
+ TESTCASE( ftell( fh ) == 10l );
+ TESTCASE( fseek( fh, 2, SEEK_CUR ) == 0 );
+ TESTCASE( ftell( fh ) == 12l );
+ TESTCASE( fseek( fh, -1, SEEK_CUR ) == 0 );
+ TESTCASE( ftell( fh ) == 11l );
+ /* Checking error handling */
+ TESTCASE( fseek( fh, -5, SEEK_SET ) == -1 );
+ TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
+ TESTCASE( fclose( fh ) == 0 );
+ return TEST_RESULTS;
+}
+
+#endif
+