add bufferevent_read_buffer function

svn:r728

ChangeLog

@@ -70,6 +70,7 @@ Changes in current version:
  o Make all event_tagging interfaces threadsafe.
  o Rename internal memory management functions.
  o New functions (event_assign, event_new, event_free) for use by apps that want to be safely threadsafe, or want to remain ignorant of the contents of struct event.
+ o introduce bufferevent_read_buffer; allows reading without memory copy.
 
 Changes in 1.4.0:
  o allow \r or \n individually to separate HTTP headers instead of the standard "\r\n"; from Charles Kerr.

evbuffer.c

@@ -325,6 +325,12 @@ bufferevent_read(struct bufferevent *bufev, void *data, size_t size)
 	return (evbuffer_remove(bufev->input, data, size));
 }
 
+int
+bufferevent_read_buffer(struct bufferevent *bufev, struct evbuffer *buf)
+{
+	return (evbuffer_add_buffer(buf, bufev->input));
+}
+
 int
 bufferevent_enable(struct bufferevent *bufev, short event)
 {

include/event2/bufferevent.h

@@ -181,6 +181,16 @@ int bufferevent_write_buffer(struct bufferevent *bufev, struct evbuffer *buf);
  */
 size_t bufferevent_read(struct bufferevent *bufev, void *data, size_t size);
 
+/**
+  Read data from a bufferevent buffer into an evbuffer.  This avoids
+  memory copies.
+
+  @param bufev the bufferevent to be read from
+  @param buf the evbuffer to which to add data
+  @return 0 if successful, or -1 if an error occurred.
+ */
+int bufferevent_read_buffer(struct bufferevent *bufev, struct evbuffer *buf);
+
 /**
   Enable a bufferevent.
 

test/regress.c

@@ -1306,8 +1306,18 @@ static void
 readcb(struct bufferevent *bev, void *arg)
 {
 	if (EVBUFFER_LENGTH(bev->input) == 8333) {
+		struct evbuffer *evbuf = evbuffer_new();
+		assert(evbuf != NULL);
+
+		/* gratuitous test of bufferevent_read_buffer */
+		bufferevent_read_buffer(bev, evbuf);
+
 		bufferevent_disable(bev, EV_READ);
-		test_ok++;
+
+		if (EVBUFFER_LENGTH(evbuf) == 8333)
+			test_ok++;
+
+		evbuffer_free(evbuf);
 	}
 }