#include "arena_allocator.h"
#include <assert.h>
#include <math.h>
#include <stddef.h>
#include <stdlib.h>

Arena arena_init(size_t capacity) {
  Arena result = {.capacity = capacity, .size = 0, .data = malloc(capacity)};
  assert(result.data != NULL);
  return result;
}

void arena_deinit(Arena *arena) {
  free(arena->data);
  *arena = (Arena){.capacity = NAN, .size = 0, .data = NULL};
}

void *arena_alloc(Arena *arena, size_t size) {
  assert(arena->size + size <= arena->capacity);
  void *result = &arena->data[arena->size];
  arena->size += size;
  return result;
}

void *arena_clear(Arena *arena) {
  arena->size = 0;
  return arena->data;
}