Provide CBS_get_last_u8().

This will be used in the TLSv1.3 record layer.

From BoringSSL.

ok tb@

1 files changed, 12 insertions, 1 deletions

diff --git a/src/lib/libssl/bs_cbs.c b/src/lib/libssl/bs_cbs.c
index ab76b78927..627c609bb9 100644
--- a/src/lib/libssl/bs_cbs.c
+++ b/src/lib/libssl/bs_cbs.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bs_cbs.c,v 1.21 2021/10/31 06:48:54 jsing Exp $       */
+/*      $OpenBSD: bs_cbs.c,v 1.22 2021/12/15 17:23:34 jsing Exp $       */
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -191,6 +191,17 @@ CBS_get_u32(CBS *cbs, uint32_t *out)
 }
 
 int
+CBS_get_last_u8(CBS *cbs, uint8_t *out)
+{
+        if (cbs->len == 0)
+                return 0;
+
+        *out = cbs->data[cbs->len - 1];
+        cbs->len--;
+        return 1;
+}
+
+int
 CBS_get_bytes(CBS *cbs, CBS *out, size_t len)
 {
         const uint8_t *v;