optimizations to json_tokener_parse_ex(), printbuf_memappend()

-- Brent Miller, bdmiller at yahoo dash inc dot com


git-svn-id: http://svn.metaparadigm.com/svn/json-c/trunk@34 327403b1-1117-474d-bef2-5cb71233fd97

printbuf.h

@@ -7,6 +7,10 @@
  * This library is free software; you can redistribute it and/or modify
  * it under the terms of the MIT license. See COPYING for details.
  *
+ *
+ * Copyright (c) 2008-2009 Yahoo! Inc.  All rights reserved.
+ * The copyrights to the contents of this file are licensed under the MIT License
+ * (http://www.opensource.org/licenses/mit-license.php)
  */
 
 #ifndef _printbuf_h_
@@ -27,9 +31,23 @@ struct printbuf {
 extern struct printbuf*
 printbuf_new(void);
 
+/* As an optimization, printbuf_memappend is defined as a macro that
+ * handles copying data if the buffer is large enough; otherwise it
+ * invokes printbuf_memappend_real() which performs the heavy lifting
+ * of realloc()ing the buffer and copying data.
+ */
 extern int
 printbuf_memappend(struct printbuf *p, const char *buf, int size);
 
+#define printbuf_memappend_fast(p, bufptr, bufsize)          \
+do {                                                         \
+  if ((p->size - p->bpos) > bufsize) {                       \
+    memcpy(p->buf + p->bpos, (bufptr), bufsize);             \
+    p->bpos += bufsize;                                      \
+    p->buf[p->bpos]= '\0';                                   \
+  } else {  printbuf_memappend(p, (bufptr), bufsize); }      \
+} while (0)
+
 extern int
 sprintbuf(struct printbuf *p, const char *msg, ...);