Restructure tables for C89 port and smaller size.

Changes the data layout of tables slightly so that string
keys are prefixed with their size, rather than the size
being inline in the table itself.

This has a few benefits:

1. inttables shrink a bit, because there is no longer a wasted
   and unused size field sitting in them.

2. This avoids the need to have a union in the table.  This is
   important for an impending C89 port of upb, since C89 has
   literally no way of statically initializing a non-first union
   member.

1 files changed, 4 insertions, 2 deletions

diff --git a/upb/bindings/lua/upb/table.c b/upb/bindings/lua/upb/table.c
index e574ab0..4bda63d 100644
--- a/upb/bindings/lua/upb/table.c
+++ b/upb/bindings/lua/upb/table.c
@@ -66,9 +66,11 @@ static void lupbtable_pushent(lua_State *L, const upb_tabent *e,
   lua_newtable(L);
   if (!upb_tabent_isempty(e)) {
     if (inttab) {
-      lua_pushnumber(L, e->key.num);
+      lua_pushnumber(L, e->key);
     } else {
-      lua_pushlstring(L, e->key.s.str, e->key.s.length);
+      uint32_t len;
+      const char *str = upb_tabstr(e->key, &len);
+      lua_pushlstring(L, str, len);
     }
     lua_setfield(L, -2, "key");
     lupbtable_pushval(L, e->val, ctype);