X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=functions%2Fstdio%2Fftell.c;h=0bf42f50698fccfacec7f1e6e8d51e9cc22ab886;hb=55cf35957bf8dec0a489ba758c02c83303a5eb50;hp=f4efecdf7973ce1ae10d69b99f841f85566af115;hpb=0a5395faab237ba9008352b0f4bee9659bbd3d5f;p=pdclib

diff --git a/functions/stdio/ftell.c b/functions/stdio/ftell.c
index f4efecd..0bf42f5 100644
--- a/functions/stdio/ftell.c
+++ b/functions/stdio/ftell.c
@@ -1,14 +1,85 @@
-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// Public Domain C Library - http://pdclib.sourceforge.net
-// This code is Public Domain. Use, modify, and redistribute at will.
-// ----------------------------------------------------------------------------
+/* $Id$ */
 
-long ftell( FILE * stream ) { /* TODO */ };
+/* ftell( FILE * )
 
-/* PDPC code - unreviewed
+   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 <limits.h>
+
+#ifndef REGTEST
+
+long int ftell( struct _PDCLIB_file_t * stream )
 {
-    return (stream->bufStartR + (stream->upto - stream->fbuf));
+    /* TODO: A bit too fuzzy in the head now. stream->ungetidx should be in here
+             somewhere.
+    */
+    if ( stream->pos.offset > ( LONG_MAX - stream->bufidx ) )
+    {
+        /* integer overflow */
+        _PDCLIB_errno = _PDCLIB_EINVAL;
+        return -1;
+    }
+    /* Position of start-of-buffer, plus:
+       - buffered, unwritten content (for output streams), or
+       - already-parsed content from buffer (for input streams)
+    */
+    return (long int)( stream->pos.offset + stream->bufidx - stream->ungetidx );
 }
-*/
+
+#endif
+
+#ifdef TEST
+#include <_PDCLIB_test.h>
+
+#include <stdlib.h>
+
+int main( void )
+{
+    /* Testing all the basic I/O functions individually would result in lots
+       of duplicated code, so I took the liberty of lumping it all together
+       here.
+    */
+    /* The following functions delegate their tests to here:
+       fgetc fflush rewind fputc ungetc fseek
+       flushbuffer seek fillbuffer prepread prepwrite
+    */
+    char * buffer = (char*)malloc( 4 );
+    FILE * fh;
+    remove( testfile );
+    TESTCASE( ( fh = fopen( testfile, "w+" ) ) != NULL );
+    TESTCASE( setvbuf( fh, buffer, _IOLBF, 4 ) == 0 );
+    TESTCASE( fputc( '1', fh ) == '1' );
+    TESTCASE( fputc( '2', fh ) == '2' );
+    TESTCASE( fputc( '3', fh ) == '3' );
+    /* Positions incrementing as expected? */
+    TESTCASE( ftell( fh ) == 3l );
+    TESTCASE_NOREG( fh->pos.offset == 0l );
+    TESTCASE_NOREG( fh->bufidx == 3l );
+    /* Buffer properly flushed when full? */
+    TESTCASE( fputc( '4', fh ) == '4' );
+    TESTCASE_NOREG( fh->pos.offset == 4l );
+    TESTCASE_NOREG( fh->bufidx == 0 );
+    /* fflush() resetting positions as expected? */
+    TESTCASE( fputc( '5', fh ) == '5' );
+    TESTCASE( fflush( fh ) == 0 );
+    TESTCASE( ftell( fh ) == 5l );
+    TESTCASE_NOREG( fh->pos.offset == 5l );
+    TESTCASE_NOREG( fh->bufidx == 0l );
+    /* rewind() resetting positions as expected? */
+    rewind( fh );
+    TESTCASE( ftell( fh ) == 0l );
+    TESTCASE_NOREG( fh->pos.offset == 0 );
+    TESTCASE_NOREG( fh->bufidx == 0 );
+    /* Reading back first character after rewind for basic read check */
+    TESTCASE( fgetc( fh ) == '1' );
+    TESTCASE( fclose( fh ) == 0 );
+    /* TODO: t.b.c. */
+    remove( testfile );
+    return TEST_RESULTS;
+}
+
+#endif
+