Added setvbuf().

[pdclib] / functions / stdio / setvbuf.c

diff --git a/functions/stdio/setvbuf.c b/functions/stdio/setvbuf.c
index a65dd8ed2528265395ed99ea4036a1e7c135bf52..c6329df9b6f07fe823a2570e3d0b3533f6fca49a 100644 (file)
--- a/functions/stdio/setvbuf.c
+++ b/functions/stdio/setvbuf.c
@@ -1,8 +1,78 @@
-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// 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 )
+{
+    /* Only allowed on "virgin" streams (i.e., before first I/O occurs), and
+       a valid value for mode.
+    */
+    if ( ( ! stream->status & _PDCLIB_VIRGINSTR ) ||
+         ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) )
+    {
+        return -1;
+    }
+    /* If a buffer is provided by user... */
+    if ( buf != NULL )
+    {
+        /* ...do not free it in library functions like fclose(), freopen(). */
+        stream->status &= ~_PDCLIB_LIBBUFFER;
+    }
+    /* If no buffer is provided by user, but required... */
+    else if ( mode != _IONBF )
+    {
+        /* Since setvbuf() may be called (successfully) on a stream only once,
+           the stream's buffer at this point should *always* be that allocated
+           by fopen(), but better make sure.
+        */
+        if ( ! ( stream->status & _PDCLIB_LIBBUFFER ) )
+        {
+            return -1;
+        }
+        /* Drop old buffer, allocate new one of requested size (unless that is
+           equal to BUFSIZ, in which case we can use the one already allocated
+           by fopen().)
+        */
+        if ( size != BUFSIZ )
+        {
+            if ( ( buf = malloc( size ) ) == NULL )
+            {
+                return -1;
+            }
+            free( stream->buffer );
+        }
+    }
+    /* Applying new settings to stream. */
+    stream->status &= ~( _IOFBF | _IOLBF | _IONBF );
+    stream->status |= mode;
+    stream->buffer = buf;
+    stream->bufsize = size;
+    stream->status &= ~_PDCLIB_VIRGINSTR;
+    return 0;
+}
+
+#endif
+
+#ifdef TEST
+#include <_PDCLIB_test.h>
+
+int main( void )
+{
+#ifndef REGTEST
+    TESTCASE( NO_TESTDRIVER );
+#else
+    puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
+#endif
+    return TEST_RESULTS;
+}
+
+#endif