From: Nick Mathewson <nickm@torproject.org>
Date: Tue, 7 Jun 2011 01:03:35 +0000 (-0400)
Subject: Allow evbuffer_ptr_set to yield a point just after the end of the buffer.
X-Git-Tag: release-2.1.1-alpha~237^2~4
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e6fe1da9ad770ac903bcee3343514041df292c5b;p=libevent

Allow evbuffer_ptr_set to yield a point just after the end of the buffer.
---

diff --git a/buffer.c b/buffer.c
index 84d3aea8..c4297ed0 100644
--- a/buffer.c
+++ b/buffer.c
@@ -2307,6 +2307,7 @@ evbuffer_ptr_set(struct evbuffer *buf, struct evbuffer_ptr *pos,
 {
 	size_t left = position;
 	struct evbuffer_chain *chain = NULL;
+	int result = 0;
 
 	EVBUFFER_LOCK(buf);
 
@@ -2333,14 +2334,18 @@ evbuffer_ptr_set(struct evbuffer *buf, struct evbuffer_ptr *pos,
 	if (chain) {
 		pos->_internal.chain = chain;
 		pos->_internal.pos_in_chain = position + left;
+	} else if (left == 0 && buf->last) {
+		pos->_internal.chain = buf->last;
+		pos->_internal.pos_in_chain = buf->last->off;
 	} else {
 		pos->_internal.chain = NULL;
 		pos->pos = -1;
+		result = -1;
 	}
 
 	EVBUFFER_UNLOCK(buf);
 
-	return chain != NULL ? 0 : -1;
+	return result;
 }
 
 /**
diff --git a/test/regress_buffer.c b/test/regress_buffer.c
index 2e5efeb1..a9a4f6a3 100644
--- a/test/regress_buffer.c
+++ b/test/regress_buffer.c
@@ -1222,6 +1222,8 @@ test_evbuffer_ptr_set(void *ptr)
 	tt_assert(pos.pos == 10000);
 	tt_assert(evbuffer_ptr_set(buf, &pos, 1000, EVBUFFER_PTR_ADD) == 0);
 	tt_assert(pos.pos == 11000);
+	tt_assert(evbuffer_ptr_set(buf, &pos, 1000, EVBUFFER_PTR_ADD) == 0);
+	tt_assert(pos.pos == 12000);
 	tt_assert(evbuffer_ptr_set(buf, &pos, 1000, EVBUFFER_PTR_ADD) == -1);
 	tt_assert(pos.pos == -1);