/*
 * Copyright 2024 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include "util/order.h"

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

typedef uint32_t KeyedCircularCacheKey;

//! Array-backed circular cache, optimized for data cache efficiency
typedef struct {
  KeyedCircularCacheKey *cache_keys;
  uint8_t *cache_data; //<! Pointer to the array
  size_t item_size; //<! Size of the array element in bytes
  size_t next_item_to_erase_idx; //<! Next array element to be deleted
  size_t total_items;
} KeyedCircularCache;

void keyed_circular_cache_init(KeyedCircularCache *c, KeyedCircularCacheKey *key_buffer,
                               void *data_buffer, size_t item_size, size_t total_items);

//! @return Pointer to buffer of entry in cache that contains the data
//! @note Item must be of size item_size
void *keyed_circular_cache_get(KeyedCircularCache *c, KeyedCircularCacheKey key);

//! Push data of size item_size into the circular cache
//! Overwrites the item at next_item_to_erase_idx
void keyed_circular_cache_push(KeyedCircularCache *c, KeyedCircularCacheKey key,
                               const void *item);