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    eˆçé„­ˆ_æ¿ë ?÷    e/* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */
/*
 * Copyright (c) Yann Collet, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of https://github.com/facebook/zstd) and
 * the GPLv2 (found in the COPYING file in the root directory of
 * https://github.com/facebook/zstd). You may select, at your option, one of the
 * above-listed licenses.
 */

#ifndef LINUX_ZSTD_H
#define LINUX_ZSTD_H

/**
 * This is a kernel-style API that wraps the upstream zstd API, which cannot be
 * used directly because the symbols aren't exported. It exposes the minimal
 * functionality which is currently required by users of zstd in the kernel.
 * Expose extra functions from lib/zstd/zstd.h as needed.
 */

/* ======   Dependency   ====== */
#include <linux/types.h>
#include <linux/zstd_errors.h>
#include <linux/zstd_lib.h>

/* ======   Helper Functions   ====== */
/**
 * zstd_compress_bound() - maximum compressed size in worst case scenario
 * @src_size: The size of the data to compress.
 *
 * Return:    The maximum compressed size in the worst case scenario.
 */
size_t zstd_compress_bound(size_t src_size);

/**
 * zstd_is_error() - tells if a size_t function result is an error code
 * @code:  The function result to check for error.
 *
 * Return: Non-zero iff the code is an error.
 */
unsigned int zstd_is_error(size_t code);

/**
 * enum zstd_error_code - zstd error codes
 */
typedef ZSTD_ErrorCode zstd_error_code;

/**
 * zstd_get_error_code() - translates an error function result to an error code
 * @code:  The function result for which zstd_is_error(code) is true.
 *
 * Return: A unique error code for this error.
 */
zstd_error_code zstd_get_error_code(size_t code);

/**
 * zstd_get_error_name() - translates an error function result to a string
 * @code:  The function result for which zstd_is_error(code) is true.
 *
 * Return: An error string corresponding to the error code.
 */
const char *zstd_get_error_name(size_t code);

/**
 * zstd_min_clevel() - minimum allowed compression level
 *
 * Return: The minimum allowed compression level.
 */
int zstd_min_clevel(void);

/**
 * zstd_max_clevel() - maximum allowed compression level
 *
 * Return: The maximum allowed compression level.
 */
int zstd_max_clevel(void);

/* ======   Parameter Selection   ====== */

/**
 * enum zstd_strategy - zstd compression search strategy
 *
 * From faster to stronger. See zstd_lib.h.
 */
typedef ZSTD_strategy zstd_strategy;

/**
 * struct zstd_compression_parameters - zstd compression parameters
 * @windowLog:    Log of the largest match distance. Larger means more
 *                compression, and more memory needed during decompression.
 * @chainLog:     Fully searched segment. Larger means more compression,
 *                slower, and more memory (useless for fast).
 * @hashLog:      Dispatch table. Larger means more compression,
 *                slower, and more memory.
 * @searchLog:    Number of searches. Larger means more compression and slower.
 * @searchLength: Match length searched. Larger means faster decompression,
 *                sometimes less compression.
 * @targetLength: Acceptable match size for optimal parser (only). Larger means
 *                more compression, and slower.
 * @strategy:     The zstd compression strategy.
 *
 * See zstd_lib.h.
 */
typedef ZSTD_compressionParameters zstd_compression_parameters;

/**
 * struct zstd_frame_parameters - zstd frame parameters
 * @contentSizeFlag: Controls whether content size will be present in the
 *                   frame header (when known).
 * @checksumFlag:    Controls whether a 32-bit checksum is generated at the
 *                   end of the frame for error detection.
 * @noDictIDFlag:    Controls whether dictID will be saved into the frame
 *                   header when using dictionary compression.
 *
 * The default value is all fields set to 0. See zstd_lib.h.
 */
typedef ZSTD_frameParameters zstd_frame_parameters;

/**
 * struct