#pragma once
#include <stddef.h>
typedef struct consumed_blk {
struct consumed_blk *prev;
} *ArenaMem;
typedef struct {
char *cur_blk;
size_t pos, size;
} Arena;
#define ARENA_BLOCK_SIZE 4096
// inits an empty arena.
#define ARENA_EMPTY { .cur_blk = NULL, .pos = 0, .size = 0 }