Added setvbuf().

[pdclib] / functions / stdio / setvbuf.c

diff --git a/functions/stdio/setvbuf.c b/functions/stdio/setvbuf.c
index 9d96ad8f8583e3681e8bdfa8d162c613a6231cab..c6329df9b6f07fe823a2570e3d0b3533f6fca49a 100644 (file)
--- a/functions/stdio/setvbuf.c
+++ b/functions/stdio/setvbuf.c
@@ -11,19 +11,52 @@
 
 #ifndef REGTEST
 
-int setvbuf( FILE * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mode, size_t size )
+int setvbuf( struct _PDCLIB_file_t * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mode, size_t size )
 {
-    /* TODO: Only allowed on a "virgin" stream; add check. */
-    if ( ( stream->status & ( _IOFBF | _IOLBF | _IONBF ) ) /* Only allowed on "virgin" stream */
-      || ( ( mode != _IOFBF ) && ( mode != _IOLBF ) && ( mode != _IONBF ) ) /* invalid mode */
-      || ( ( buf == NULL ) && ( ( buf = malloc( size ) ) == NULL ) ) /* no memory available */
-    )
+    /* 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->buffer = buf;
     stream->bufsize = size;
+    stream->status &= ~_PDCLIB_VIRGINSTR;
     return 0;
 }
 
@@ -34,7 +67,11 @@ int setvbuf( FILE * _PDCLIB_restrict stream, char * _PDCLIB_restrict buf, int mo
 
 int main( void )
 {
+#ifndef REGTEST
     TESTCASE( NO_TESTDRIVER );
+#else
+    puts( " NOTEST setvbuf() test driver is PDCLib-specific." );
+#endif
     return TEST_RESULTS;
 }