1 /* fseek( FILE *, long offset, int )
3 This file is part of the Public Domain C Library (PDCLib).
4 Permission is granted to use, modify, and / or redistribute at will.
10 #include <_PDCLIB_io.h>
12 int _PDCLIB_fseek_unlocked( FILE * stream, long loffset, int whence )
14 _PDCLIB_int64_t offset = loffset;
15 if ( stream->status & _PDCLIB_FWRITE )
17 if ( _PDCLIB_flushbuffer( stream ) == EOF )
22 stream->status &= ~ _PDCLIB_EOFFLAG;
23 if ( stream->status & _PDCLIB_FRW )
25 stream->status &= ~ ( _PDCLIB_FREAD | _PDCLIB_FWRITE );
28 if ( whence == SEEK_CUR )
31 offset += _PDCLIB_ftell64_unlocked( stream );
34 return ( _PDCLIB_seek( stream, offset, whence ) != EOF ) ? 0 : EOF;
37 int fseek( FILE * stream, long loffset, int whence )
39 _PDCLIB_flockfile( stream );
40 int r = _PDCLIB_fseek_unlocked( stream, loffset, whence );
41 _PDCLIB_funlockfile( stream );
48 #include <_PDCLIB_test.h>
54 TESTCASE( ( fh = tmpfile() ) != NULL );
55 TESTCASE( fwrite( teststring, 1, strlen( teststring ), fh ) == strlen( teststring ) );
56 /* General functionality */
57 TESTCASE( fseek( fh, -1, SEEK_END ) == 0 );
58 TESTCASE( (size_t)ftell( fh ) == strlen( teststring ) - 1 );
59 TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
60 TESTCASE( (size_t)ftell( fh ) == strlen( teststring ) );
61 TESTCASE( fseek( fh, 0, SEEK_SET ) == 0 );
62 TESTCASE( ftell( fh ) == 0 );
63 TESTCASE( fseek( fh, 5, SEEK_CUR ) == 0 );
64 TESTCASE( ftell( fh ) == 5 );
65 TESTCASE( fseek( fh, -3, SEEK_CUR ) == 0 );
66 TESTCASE( ftell( fh ) == 2 );
67 /* Checking behaviour around EOF */
68 TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
69 TESTCASE( ! feof( fh ) );
70 TESTCASE( fgetc( fh ) == EOF );
71 TESTCASE( feof( fh ) );
72 TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
73 TESTCASE( ! feof( fh ) );
74 /* Checking undo of ungetc() */
75 TESTCASE( fseek( fh, 0, SEEK_SET ) == 0 );
76 TESTCASE( fgetc( fh ) == teststring[0] );
77 TESTCASE( fgetc( fh ) == teststring[1] );
78 TESTCASE( fgetc( fh ) == teststring[2] );
79 TESTCASE( ftell( fh ) == 3 );
80 TESTCASE( ungetc( teststring[2], fh ) == teststring[2] );
81 TESTCASE( ftell( fh ) == 2 );
82 TESTCASE( fgetc( fh ) == teststring[2] );
83 TESTCASE( ftell( fh ) == 3 );
84 TESTCASE( ungetc( 'x', fh ) == 'x' );
85 TESTCASE( ftell( fh ) == 2 );
86 TESTCASE( fgetc( fh ) == 'x' );
87 TESTCASE( ungetc( 'x', fh ) == 'x' );
88 TESTCASE( ftell( fh ) == 2 );
89 TESTCASE( fseek( fh, 2, SEEK_SET ) == 0 );
90 TESTCASE( fgetc( fh ) == teststring[2] );
91 /* PDCLIB-7: Check that we handle the underlying file descriptor correctly
92 * in the SEEK_CUR case */
93 TESTCASE( fseek( fh, 10, SEEK_SET ) == 0 );
94 TESTCASE( ftell( fh ) == 10l );
95 TESTCASE( fseek( fh, 0, SEEK_CUR ) == 0 );
96 TESTCASE( ftell( fh ) == 10l );
97 TESTCASE( fseek( fh, 2, SEEK_CUR ) == 0 );
98 TESTCASE( ftell( fh ) == 12l );
99 TESTCASE( fseek( fh, -1, SEEK_CUR ) == 0 );
100 TESTCASE( ftell( fh ) == 11l );
101 /* Checking error handling */
102 TESTCASE( fseek( fh, -5, SEEK_SET ) == -1 );
103 TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
104 TESTCASE( fclose( fh ) == 0 );