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/*
* Copyright (c) 2012 Dave Vasilevsky <dave@vasilevsky.ca>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SQFS_CACHE_H
#define SQFS_CACHE_H
#include "common.h"
/* Really simplistic cache
* - Linear search
* - Linear eviction
* - No thread safety
* - Misses are caller's responsibility
*/
typedef uint64_t sqfs_cache_idx;
typedef void (*sqfs_cache_dispose)(void* data);
struct sqfs_cache_internal;
typedef struct sqfs_cache_internal *sqfs_cache;
sqfs_err sqfs_cache_init(sqfs_cache *cache, size_t size, size_t count,
sqfs_cache_dispose dispose);
void sqfs_cache_destroy(sqfs_cache *cache);
/* Get an entry for the given index.
*
* This will always succeed (evicting if necessary). The caller must then
* call sqfs_cache_entry_valid() to determine if the entry is valid. If not
* valid, the entry is newly allocated and the caller is responsible for
* initializing it and then calling sqfs_cache_entry_mark_valid().
*
* This call may block in multithreaded case.
*
* In multithreaded case, the cache is locked on return (no entries can
* be added or removed). Caller must call sqfs_cache_put() when it is safe
* to evict the returned cache entry.
*/
void *sqfs_cache_get(sqfs_cache *cache, sqfs_cache_idx idx);
/* inform cache it is now safe to evict this entry. */
void sqfs_cache_put(const sqfs_cache *cache, const void *e);
/* Determine if cache entry contains valid contents. */
int sqfs_cache_entry_valid(const sqfs_cache *cache, const void *e);
/* Mark cache entry as containing valid contents. */
void sqfs_cache_entry_mark_valid(sqfs_cache *cache, void *e);
#endif
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