Skeleton implementation for now.

[pdclib] / functions / stdio / setvbuf.c

diff --git a/functions/stdio/setvbuf.c b/functions/stdio/setvbuf.c
index a65dd8ed2528265395ed99ea4036a1e7c135bf52..5ac14a9357345653e7e64d7b980999c7d4b806b3 100644 (file)
--- a/functions/stdio/setvbuf.c
+++ b/functions/stdio/setvbuf.c
@@ -1,8 +1,126 @@
-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// Public Domain C Library - http://pdclib.sourceforge.net
-// This code is Public Domain. Use, modify, and redistribute at will.
-// ----------------------------------------------------------------------------
-
-int setvbuf( FILE * restrict stream, char * restrict buf, int mode, size_t size ) { /* TODO */ };
+/* $Id$ */
+
+/* setvbuf( FILE *, char *, int, size_t )
+
+   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 <stdlib.h>
+
+#ifndef REGTEST
+
+int setvbuf( struct _PDCLIB_file_t * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mode, size_t size )
+{
+    /* TODO: Honor user-provided buffer / buffer size. (Not actually required
+       by the standard...) */
+    stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
+    stream->status |= mode; /* TODO: Unchecked use of mode -> vulnerable. */
+    return 0;
+
+#if 0
+    /* Only allowed on "virgin" streams (i.e., before first I/O occurs), a
+       valid value for mode, and only once per stream (i.e., the buffer
+       attached to the stream should always be the one allocated by fopen().
+    */
+    if ( ( ! stream->status & _PDCLIB_VIRGINSTR ) ||
+         ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) ||
+         ! ( stream->status & _PDCLIB_LIBBUFFER ) )
+    {
+        return -1;
+    }
+    if ( mode == _IONBF )
+    {
+        /* When unbuffered I/O is requested, we don't need a buffer. */
+        buf = NULL;
+        size = 0;
+    }
+    else
+    {
+        /* The standard does not really require this - only BUFSIZ is required
+           to be no smaller than 256 - but it makes sense not to make buffers
+           too small anyway.
+        */
+        if ( size < 256 )
+        {
+            buf = NULL; /* do not use too-small user buffer */
+            size = 256;
+        }
+    }
+    /* If a suitable buffer is provided by user... */
+    if ( buf != NULL )
+    {
+        /* ...do not free it in library functions like fclose(), freopen(). */
+        stream->status &= ~_PDCLIB_LIBBUFFER;
+    }
+    /* If we cannot allocate enough memory, that is not a reason for failure -
+       the standard does not actually *require* that setvbuf() honors user-
+       supplied buffer and buffer size, so we can quietly ignore this.
+    */
+    /* FIXME: Logic stops here. Handle _IONBF, new buf value etc. correctly. */
+    puts("foo");
+    if ( ( ( buf = malloc( size ) ) != NULL ) || ( mode == _IONBF ) )
+    {
+        free( stream->buffer );
+    }
+    puts("bar");
+    /* Applying new settings to stream. */
+    stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
+    stream->status |= mode;
+    stream->bufsize = size;
+    stream->status &= ~_PDCLIB_VIRGINSTR;
+    return 0;
+#endif
+}
+
+#endif
+
+#ifdef TEST
+#include <_PDCLIB_test.h>
+
+#define BUFFERSIZE 500
+
+int main( void )
+{
+#ifndef REGTEST
+    char const * const filename = "testfile";
+    char buffer[ BUFFERSIZE ];
+    struct _PDCLIB_file_t * fh;
+    /* full buffered, user-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+    TESTCASE( fh->status & _PDCLIB_LIBBUFFER );
+    TESTCASE( fh->bufsize == BUFSIZ );
+    TESTCASE( setvbuf( fh, buffer, _IOFBF, BUFFERSIZE ) == 0 );
+#if 0
+    TESTCASE( fh->buffer == buffer );
+    TESTCASE( fh->bufsize == BUFFERSIZE );
+#endif
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOFBF );
+    TESTCASE( fclose( fh ) == 0 );
+    /* line buffered, lib-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+    TESTCASE( setvbuf( fh, NULL, _IOLBF, BUFFERSIZE ) == 0 );
+#if 0
+    TESTCASE( fh->buffer != buffer );
+    TESTCASE( fh->buffer != NULL );
+    TESTCASE( fh->bufsize == BUFFERSIZE );
+#endif
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IOLBF );
+    TESTCASE( fclose( fh ) == 0 );
+    /* not buffered, user-supplied buffer */
+    TESTCASE( ( fh = fopen( filename, "w" ) ) != NULL );
+    TESTCASE( setvbuf( fh, buffer, _IONBF, BUFFERSIZE ) == 0 );
+#if 0
+    TESTCASE( fh->buffer == NULL );
+    TESTCASE( fh->bufsize == 0 );
+#endif
+    TESTCASE( ( fh->status & ( _IOFBF | _IONBF | _IOLBF ) ) == _IONBF );
+    TESTCASE( fclose( fh ) == 0 );
+#else
+    puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
+#endif
+    return TEST_RESULTS;
+}
+
+#endif