Function checkstacksizes

Source/Misc/lua/src/lua.c:6243–6255

static void checkstacksizes (lua_State *L, StkId max) {
int ci_used = cast_int(L->ci - L->base_ci);  /* number of `ci' in use */
int s_used = cast_int(max - L->stack);  /* part of stack in use */
if (L->size_ci > LUAI_MAXCALLS)  /* handling overflow? */
return;  /* do not touch the stacks */
if (4*ci_used < L->size_ci && 2*BASIC_CI_SIZE < L->size_ci)
luaD_reallocCI(L, L->size_ci/2);  /* still big enough... */
condhardstacktests(luaD_reallocCI(L, ci_used + 1));
if (4*s_used < L->stacksize &&
2*(BASIC_STACK_SIZE+EXTRA_STACK) < L->stacksize)
luaD_reallocstack(L, L->stacksize/2);  /* still big enough... */
condhardstacktests(luaD_reallocstack(L, s_used));
}


static void traversestack (global_State *g, lua_State *l) {