Add test for gbuf

include/ucore/ucore_buffer.h

@@ -26,7 +26,7 @@ struct GBuf {
 	void *buf;
 };
 
-/** Allocatea new GBuf.
+/** Allocate a new GBuf.
  *
  * @param initsz Intial capacity of the GBuf
  * @return New GBuf, or NULL if allocation fails,
@@ -56,7 +56,18 @@ void uc_gbuf_unref(GBuf *buf);
  * @return 0 on success, -1 on failure when allocation fails if he buffer
  * needs to grow
  */
-int uc_gbuf_append(GBuf *buf,void *data,size_t len);
+int uc_gbuf_append(GBuf *buf,const void *data,size_t len);
+
+/** Do printf formatting on a GBuf.
+ * The buffer will grow as needed.
+ *
+ * @param buf The GBuf
+ * @param fmt printf stype formatting string
+ * @param ... format arguments
+ * 
+ * @return The number of chars written, or negative if an error occurs
+ */
+int uc_gbuf_printf(GBuf *buf, const char *fmt, ...);
 
 /** Expand the capacity of the GBuf.
  *
@@ -69,7 +80,7 @@ int uc_gbuf_grow(GBuf *buf, size_t addlen);
  * @param buff buffer
  * @return length of unused space
  */
-size_t uc_gbuf_remaining(const GBuf *buf)
+static inline size_t uc_gbuf_remaining(const GBuf *buf)
 {
     return buf->len - buf->used;
 }