allocator: add arena_allocator

This allocator uses Lua userdatas for dynamic allocation
that is automatically freed when the current scope exits.
This commit is contained in:
takase1121 2024-07-09 18:01:30 +08:00 committed by Guldoman
parent 0966be64b0
commit 9293a317cd
3 changed files with 70 additions and 0 deletions

44
src/arena_allocator.c Normal file
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@ -0,0 +1,44 @@
#include "arena_allocator.h"
#include <string.h>
#include <lauxlib.h>
void lxl_arena_init(lua_State *L, lxl_arena *arena) {
lua_newtable(L);
arena->L = L; arena->ref = lua_gettop(L);
}
void *lxl_arena_malloc(lxl_arena *arena, size_t size) {
if (!arena || !arena->L) return NULL;
if (!lua_istable(arena->L, arena->ref)) luaL_error(arena->L, "invalid arena reference");
void *data = lua_newuserdata(arena->L, size);
lua_pushlightuserdata(arena->L, data);
lua_pushvalue(arena->L, -2);
lua_settable(arena->L, arena->ref);
lua_pop(arena->L, 1);
return data;
}
void *lxl_arena_zero(lxl_arena *arena, size_t size) {
void *v = lxl_arena_malloc(arena, size);
return v ? memset(v, 0, size) : NULL;
}
char *lxl_arena_strdup(lxl_arena *arena, const char *str) {
if (!str) return NULL;
return lxl_arena_copy(arena, (void *) str, (strlen(str) + 1) * sizeof(char));
}
char *lxl_arena_copy(lxl_arena *arena, void *ptr, size_t len) {
if (!ptr) return NULL;
char *output = lxl_arena_malloc(arena, sizeof(char) * len);
return output ? memcpy(output, ptr, len) : NULL;
}
void lxl_arena_free(lxl_arena *arena, void *ptr) {
if (!arena || !arena->L || !ptr) return;
if (!lua_istable(arena->L, arena->ref)) luaL_error(arena->L, "invalid arena reference");
lua_pushlightuserdata(arena->L, ptr);
lua_pushnil(arena->L);
lua_settable(arena->L, arena->ref);
}

25
src/arena_allocator.h Normal file
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/**
* An arena allocator using the Lua state; similar to luaL_Buffer.
* Initialize the arena with lxl_arena_init(), and you can use lxl_arena_malloc(),
* lxl_arena_zero() to allocate (and optionally zero) the memory.
* lxl_arena_free() can be optionally used to free memory, but this is generally not needed.
*/
#ifndef LUA_ALLOCATOR_H
#define LUA_ALLOCATOR_H
#include <lua.h>
typedef struct lxl_arena {
lua_State *L;
int ref;
} lxl_arena;
void lxl_arena_init(lua_State *L, lxl_arena *arena);
void *lxl_arena_malloc(lxl_arena *arena, size_t size);
void *lxl_arena_zero(lxl_arena *arena, size_t size);
char *lxl_arena_copy(lxl_arena *arena, void *ptr, size_t len);
char *lxl_arena_strdup(lxl_arena *arena, const char *str);
void lxl_arena_free(lxl_arena *arena, void *ptr);
#endif

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@ -6,6 +6,7 @@ lite_sources = [
'api/system.c',
'api/process.c',
'api/utf8.c',
'arena_allocator.c',
'renderer.c',
'renwindow.c',
'rencache.c',