Added evbuffer_add_iovec and unit tests.

buffer.c

@@ -589,6 +589,37 @@ evbuffer_get_contiguous_space(const struct evbuffer *buf)
 	return result;
 }
 
+size_t
+evbuffer_add_iovec(struct evbuffer * buf, struct evbuffer_iovec * vec, int n_vec) {
+	int n;
+	size_t res;
+	size_t to_alloc;
+
+	EVBUFFER_LOCK(buf);
+
+	res = to_alloc = 0;
+
+	for (n = 0; n < n_vec; n++) {
+		to_alloc += vec[n].iov_len;
+	}
+
+	if (evbuffer_expand(buf, to_alloc) < 0) {
+		goto done;
+	}
+
+	for (n = 0; n < n_vec; n++) {
+		if (evbuffer_add(buf, vec[n].iov_base, vec[n].iov_len) < 0) {
+			goto done;
+		}
+
+		res += vec[n].iov_len;
+	}
+
+done:
+    EVBUFFER_UNLOCK(buf);
+    return res;
+}
+
 int
 evbuffer_reserve_space(struct evbuffer *buf, ev_ssize_t size,
     struct evbuffer_iovec *vec, int n_vecs)

include/event2/buffer.h

@@ -950,6 +950,21 @@ struct event_base;
  */
 int evbuffer_defer_callbacks(struct evbuffer *buffer, struct event_base *base);
 
+/**
+  Append data from 1 or more iovec's to an evbuffer
+
+  Calculates the number of bytes needed for an iovec structure and guarantees
+  all data will fit into a single chain. Can be used in lieu of functionality
+  which calls evbuffer_add() constantly before being used to increase
+  performance.
+
+  @param buffer the destination buffer
+  @param vec the source iovec
+  @param n_vec the number of iovec structures.
+  @return the number of bytes successfully written to the output buffer.
+*/
+size_t evbuffer_add_iovec(struct evbuffer * buffer, struct evbuffer_iovec * vec, int n_vec);
+
 #ifdef __cplusplus
 }
 #endif

test/regress_buffer.c

@@ -1827,6 +1827,49 @@ end:
 		evbuffer_free(tmp_buf);
 }
 
+static void
+test_evbuffer_add_iovec(void * ptr)
+{
+	struct evbuffer * buf = NULL;
+	struct evbuffer_iovec vec[4];
+	const char * data[] = {
+		"Guilt resembles a sword with two edges.",
+		"On the one hand, it cuts for Justice, imposing practical morality upon those who fear it.",
+		"Conscience does not always adhere to rational judgment.",
+		"Guilt is always a self-imposed burden, but it is not always rightly imposed."
+	};
+	size_t expected_length = 0;
+	size_t returned_length = 0;
+	int i;
+
+	buf = evbuffer_new();
+
+	for (i = 0; i < 4; i++) {
+		vec[i].iov_len  = strlen(data[i]);
+		vec[i].iov_base = data[i];
+		expected_length += vec[i].iov_len;
+	}
+
+	returned_length = evbuffer_add_iovec(buf, vec, 4);
+
+	tt_int_op(returned_length, ==, evbuffer_get_length(buf));
+	tt_int_op(evbuffer_get_length(buf), ==, expected_length);
+
+	for (i = 0; i < 4; i++) {
+		char charbuf[1024];
+
+		memset(charbuf, 0, 1024);
+		evbuffer_remove(buf, charbuf, strlen(data[i]));
+		tt_assert(strcmp(charbuf, data[i]) == 0);
+	}
+
+	tt_assert(evbuffer_get_length(buf) == 0);
+end:
+	if (buf) {
+		evbuffer_free(buf);
+	}
+}
+
 static void *
 setup_passthrough(const struct testcase_t *testcase)
 {
@@ -1865,6 +1908,7 @@ struct testcase_t evbuffer_testcases[] = {
 	{ "peek", test_evbuffer_peek, 0, NULL, NULL },
 	{ "freeze_start", test_evbuffer_freeze, 0, &nil_setup, (void*)"start" },
 	{ "freeze_end", test_evbuffer_freeze, 0, &nil_setup, (void*)"end" },
+	{ "add_iovec", test_evbuffer_add_iovec, 0, NULL, NULL},
 
 #define ADDFILE_TEST(name, parameters)					\
 	{ name, test_evbuffer_add_file, TT_FORK|TT_NEED_BASE,		\