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slot based allocator for lua, usage of lua_createtable

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veclavtalica
2025-01-12 02:44:41 +03:00
parent 46e077ba63
commit e8b02570a2
3 changed files with 60 additions and 6 deletions
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48
apps/twnlua/game.c
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@ -43,6 +43,50 @@ static int physfs_loader(lua_State *L) {
}
/* WARN! experimental and will probably be removed */
/* it was an attempt to ease memory usage problems posed by using lua */
/* it saved ~100MiB, but it still hogs ~500MiB for no reason on my PC */
static void *custom_alloc(void *ud, void *ptr, size_t osize, size_t nsize) {
(void)ud;
/* small allocations are placed in slots, as there's a big chance they will not need to be resized */
static char slots[1024][64];
static int16_t free_slots[1024] = { [0] = -1 };
static size_t free_slot_count = 1024;
if (free_slots[0] == -1)
for (int i = 0; i < 1024; i++)
free_slots[i] = (int16_t)i;
if (nsize == 0) {
if (ptr && (char *)ptr >= &slots[0][0] && (char *)ptr <= &slots[1024-1][64-1])
free_slots[free_slot_count++] = (int16_t)(((uintptr_t)ptr - (uintptr_t)slots) / 64);
else
SDL_free(ptr);
return NULL;
} else {
if (!ptr && nsize <= 64 && free_slot_count > 0) {
/* use a slot */
return slots[free_slots[--free_slot_count]];
}
if ((char *)ptr >= &slots[0][0] && (char *)ptr <= &slots[1024-1][64-1]) {
/* still fits */
if (nsize <= 64)
return ptr;
/* move from slot to dynamic memory */
void *mem = SDL_malloc(nsize);
SDL_memcpy(mem, ptr, osize);
free_slots[free_slot_count++] = (int16_t)(((uintptr_t)ptr - (uintptr_t)slots) / 64);
return mem;
}
return SDL_realloc(ptr, nsize);
}
}
void game_tick(void) {
if (ctx.initialization_needed) {
if (!ctx.udata)
@ -57,6 +101,8 @@ void game_tick(void) {
}
state->L = luaL_newstate();
lua_setallocf(state->L, custom_alloc, NULL);
/* fakey version of luaL_openlibs() that excludes file i/o and os stuff */
{
static const luaL_Reg loaded_libs[] = {
@ -79,7 +125,7 @@ void game_tick(void) {
/* package.searchers = { physfs_loader } */
lua_getglobal(state->L, "package");
lua_newtable(state->L);
lua_createtable(state->L, 0, 1);
lua_setfield(state->L, -2, "searchers");
lua_getfield(state->L, -1, "searchers");