X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=functions%2Fstdio%2Ffseek.c;h=44cc6fbf86a8ca2f8a80bbace841f84ebd3453ad;hb=HEAD;hp=7bffffb1417618f0f78b07846c715edd9e3440e4;hpb=dcc8a8e99f69e090a03b7b868443addbc0817820;p=pdclib.old

diff --git a/functions/stdio/fseek.c b/functions/stdio/fseek.c
index 7bffffb..44cc6fb 100644
--- a/functions/stdio/fseek.c
+++ b/functions/stdio/fseek.c
@@ -1,8 +1,111 @@
-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// 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_io.h>
+
+int _PDCLIB_fseek_unlocked( FILE * 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_unlocked( stream );
+    }
+
+    return ( _PDCLIB_seek( stream, offset, whence ) != EOF ) ? 0 : EOF;
+}
+
+int fseek( FILE * stream, long loffset, int whence )
+{
+    _PDCLIB_flockfile( stream );
+    int r = _PDCLIB_fseek_unlocked( stream, loffset, whence );
+    _PDCLIB_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
+