Add infrastructure for better extension handling.

Rather than four massive functions that handle every extension,
organise the code by extension with four smaller functions for each.

Change-Id: I876b31dacb05aca9884ed3ae7c48462e6ffe3b49
Reviewed-on: https://boringssl-review.googlesource.com/5142
Reviewed-by: Adam Langley <agl@google.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/crypto/bytestring/cbb.c b/crypto/bytestring/cbb.c
index f1e09a2a..290d16fa 100644
--- a/crypto/bytestring/cbb.c
+++ b/crypto/bytestring/cbb.c
@@ -243,6 +243,12 @@ int CBB_flush(CBB *cbb) {
   return 1;
 }
 
+size_t CBB_len(const CBB *cbb) {
+  assert(cbb->child == NULL);
+  assert(!cbb->base->can_resize);
+
+  return cbb->base->cap - cbb->base->len;
+}
 
 static int cbb_add_length_prefixed(CBB *cbb, CBB *out_contents,
                                    size_t len_len) {