Parser: let cbor_value_leave_container() consume the Break

Instead of consuming it at the end of the last element of a map or array
of unknown length. This allows us to obtain the pointer to or offset of
the Break byte.

Signed-off-by: Thiago Macieira <thiago.macieira@intel.com>

src/cborparser.c

@@ -268,9 +268,9 @@ static CborError preparse_next_value_nodecrement(CborValue *it)
             /* but we weren't expecting it! */
             return CborErrorUnexpectedBreak;
         }
-        advance_bytes(it, 1);
         it->type = CborInvalidType;
         it->remaining = 0;
+        it->flags |= CborIteratorFlag_UnknownLength; /* leave_container must consume the Break */
         return CborNoError;
     }
 
@@ -286,6 +286,7 @@ static CborError preparse_next_value(CborValue *it)
     if (it->remaining != UINT32_MAX) {
         if (itemCounts && --it->remaining == 0) {
             it->type = CborInvalidType;
+            it->flags &= ~CborIteratorFlag_UnknownLength; /* no Break to consume */
             return CborNoError;
         }
     }
@@ -604,7 +605,10 @@ CborError cbor_value_leave_container(CborValue *it, const CborValue *recursed)
 {
     cbor_assert(cbor_value_is_container(it));
     cbor_assert(recursed->type == CborInvalidType);
+
     copy_current_position(it, recursed);
+    if (recursed->flags & CborIteratorFlag_UnknownLength)
+        advance_bytes(it, 1);
     return preparse_next_value(it);
 }