include/linux/xxhash.h - linux/torvalds/linux - Git at Google

 /*
  * xxHash - Extremely Fast Hash algorithm
  * Copyright (C) 2012-2016, Yann Collet.
  *
  * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *   * Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  *   * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "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 COPYRIGHT
  * OWNER OR CONTRIBUTORS 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.
  *
  * This program is free software; you can redistribute it and/or modify it under
  * the terms of the GNU General Public License version 2 as published by the
  * Free Software Foundation. This program is dual-licensed; you may select
  * either version 2 of the GNU General Public License ("GPL") or BSD license
  * ("BSD").
  *
  * You can contact the author at:
  * - xxHash homepage: http://cyan4973.github.io/xxHash/
  * - xxHash source repository: https://github.com/Cyan4973/xxHash
  */

 /*
  * Notice extracted from xxHash homepage:
  *
  * xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
  * It also successfully passes all tests from the SMHasher suite.
  *
  * Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2
  * Duo @3GHz)
  *
  * Name            Speed       Q.Score   Author
  * xxHash          5.4 GB/s     10
  * CrapWow         3.2 GB/s      2       Andrew
  * MumurHash 3a    2.7 GB/s     10       Austin Appleby
  * SpookyHash      2.0 GB/s     10       Bob Jenkins
  * SBox            1.4 GB/s      9       Bret Mulvey
  * Lookup3         1.2 GB/s      9       Bob Jenkins
  * SuperFastHash   1.2 GB/s      1       Paul Hsieh
  * CityHash64      1.05 GB/s    10       Pike & Alakuijala
  * FNV             0.55 GB/s     5       Fowler, Noll, Vo
  * CRC32           0.43 GB/s     9
  * MD5-32          0.33 GB/s    10       Ronald L. Rivest
  * SHA1-32         0.28 GB/s    10
  *
  * Q.Score is a measure of quality of the hash function.
  * It depends on successfully passing SMHasher test set.
  * 10 is a perfect score.
  *
  * A 64-bits version, named xxh64 offers much better speed,
  * but for 64-bits applications only.
  * Name     Speed on 64 bits    Speed on 32 bits
  * xxh64       13.8 GB/s            1.9 GB/s
  * xxh32        6.8 GB/s            6.0 GB/s
  */

 #ifndef XXHASH_H
 #define XXHASH_H

 #include <linux/types.h>

 /*-****************************
  * Simple Hash Functions
  *****************************/

 /**
  * xxh32() - calculate the 32-bit hash of the input with a given seed.
  *
  * @input:  The data to hash.
  * @length: The length of the data to hash.
  * @seed:   The seed can be used to alter the result predictably.
  *
  * Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
  *
  * Return:  The 32-bit hash of the data.
  */
 uint32_t xxh32(const void *input, size_t length, uint32_t seed);

 /**
  * xxh64() - calculate the 64-bit hash of the input with a given seed.
  *
  * @input:  The data to hash.
  * @length: The length of the data to hash.
  * @seed:   The seed can be used to alter the result predictably.
  *
  * This function runs 2x faster on 64-bit systems, but slower on 32-bit systems.
  *
  * Return:  The 64-bit hash of the data.
  */
 uint64_t xxh64(const void *input, size_t length, uint64_t seed);

 /**
  * xxhash() - calculate wordsize hash of the input with a given seed
  * @input:  The data to hash.
  * @length: The length of the data to hash.
  * @seed:   The seed can be used to alter the result predictably.
  *
  * If the hash does not need to be comparable between machines with
  * different word sizes, this function will call whichever of xxh32()
  * or xxh64() is faster.
  *
  * Return:  wordsize hash of the data.
  */

 static inline unsigned long xxhash(const void *input, size_t length,
 				   uint64_t seed)
 {
 #if BITS_PER_LONG == 64
        return xxh64(input, length, seed);
 #else
        return xxh32(input, length, seed);
 #endif
 }

 /*-****************************
  * Streaming Hash Functions
  *****************************/

 /*
  * These definitions are only meant to allow allocation of XXH state
  * statically, on stack, or in a struct for example.
  * Do not use members directly.
  */

 /**
  * struct xxh32_state - private xxh32 state, do not use members directly
  */
 struct xxh32_state {
 	uint32_t total_len_32;
 	uint32_t large_len;
 	uint32_t v1;
 	uint32_t v2;
 	uint32_t v3;
 	uint32_t v4;
 	uint32_t mem32[4];
 	uint32_t memsize;
 };

 /**
  * struct xxh32_state - private xxh64 state, do not use members directly
  */
 struct xxh64_state {
 	uint64_t total_len;
 	uint64_t v1;
 	uint64_t v2;
 	uint64_t v3;
 	uint64_t v4;
 	uint64_t mem64[4];
 	uint32_t memsize;
 };

 /**
  * xxh32_reset() - reset the xxh32 state to start a new hashing operation
  *
  * @state: The xxh32 state to reset.
  * @seed:  Initialize the hash state with this seed.
  *
  * Call this function on any xxh32_state to prepare for a new hashing operation.
  */
 void xxh32_reset(struct xxh32_state *state, uint32_t seed);

 /**
  * xxh32_update() - hash the data given and update the xxh32 state
  *
  * @state:  The xxh32 state to update.
  * @input:  The data to hash.
  * @length: The length of the data to hash.
  *
  * After calling xxh32_reset() call xxh32_update() as many times as necessary.
  *
  * Return:  Zero on success, otherwise an error code.
  */
 int xxh32_update(struct xxh32_state *state, const void *input, size_t length);

 /**
  * xxh32_digest() - produce the current xxh32 hash
  *
  * @state: Produce the current xxh32 hash of this state.
  *
  * A hash value can be produced at any time. It is still possible to continue
  * inserting input into the hash state after a call to xxh32_digest(), and
  * generate new hashes later on, by calling xxh32_digest() again.
  *
  * Return: The xxh32 hash stored in the state.
  */
 uint32_t xxh32_digest(const struct xxh32_state *state);

 /**
  * xxh64_reset() - reset the xxh64 state to start a new hashing operation
  *
  * @state: The xxh64 state to reset.
  * @seed:  Initialize the hash state with this seed.
  */
 void xxh64_reset(struct xxh64_state *state, uint64_t seed);

 /**
  * xxh64_update() - hash the data given and update the xxh64 state
  * @state:  The xxh64 state to update.
  * @input:  The data to hash.
  * @length: The length of the data to hash.
  *
  * After calling xxh64_reset() call xxh64_update() as many times as necessary.
  *
  * Return:  Zero on success, otherwise an error code.
  */
 int xxh64_update(struct xxh64_state *state, const void *input, size_t length);

 /**
  * xxh64_digest() - produce the current xxh64 hash
  *
  * @state: Produce the current xxh64 hash of this state.
  *
  * A hash value can be produced at any time. It is still possible to continue
  * inserting input into the hash state after a call to xxh64_digest(), and
  * generate new hashes later on, by calling xxh64_digest() again.
  *
  * Return: The xxh64 hash stored in the state.
  */
 uint64_t xxh64_digest(const struct xxh64_state *state);

 /*-**************************
  * Utils
  ***************************/

 /**
  * xxh32_copy_state() - copy the source state into the destination state
  *
  * @src: The source xxh32 state.
  * @dst: The destination xxh32 state.
  */
 void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src);

 /**
  * xxh64_copy_state() - copy the source state into the destination state
  *
  * @src: The source xxh64 state.
  * @dst: The destination xxh64 state.
  */
 void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src);

 #endif /* XXHASH_H */
	/*
	* xxHash - Extremely Fast Hash algorithm
	* Copyright (C) 2012-2016, Yann Collet.
	*
	* BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "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 COPYRIGHT
	* OWNER OR CONTRIBUTORS 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.
	*
	* This program is free software; you can redistribute it and/or modify it under
	* the terms of the GNU General Public License version 2 as published by the
	* Free Software Foundation. This program is dual-licensed; you may select
	* either version 2 of the GNU General Public License ("GPL") or BSD license
	* ("BSD").
	*
	* You can contact the author at:
	* - xxHash homepage: http://cyan4973.github.io/xxHash/
	* - xxHash source repository: https://github.com/Cyan4973/xxHash
	*/

	/*
	* Notice extracted from xxHash homepage:
	*
	* xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
	* It also successfully passes all tests from the SMHasher suite.
	*
	* Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2
	* Duo @3GHz)
	*
	* Name Speed Q.Score Author
	* xxHash 5.4 GB/s 10
	* CrapWow 3.2 GB/s 2 Andrew
	* MumurHash 3a 2.7 GB/s 10 Austin Appleby
	* SpookyHash 2.0 GB/s 10 Bob Jenkins
	* SBox 1.4 GB/s 9 Bret Mulvey
	* Lookup3 1.2 GB/s 9 Bob Jenkins
	* SuperFastHash 1.2 GB/s 1 Paul Hsieh
	* CityHash64 1.05 GB/s 10 Pike & Alakuijala
	* FNV 0.55 GB/s 5 Fowler, Noll, Vo
	* CRC32 0.43 GB/s 9
	* MD5-32 0.33 GB/s 10 Ronald L. Rivest
	* SHA1-32 0.28 GB/s 10
	*
	* Q.Score is a measure of quality of the hash function.
	* It depends on successfully passing SMHasher test set.
	* 10 is a perfect score.
	*
	* A 64-bits version, named xxh64 offers much better speed,
	* but for 64-bits applications only.
	* Name Speed on 64 bits Speed on 32 bits
	* xxh64 13.8 GB/s 1.9 GB/s
	* xxh32 6.8 GB/s 6.0 GB/s
	*/

	#ifndef XXHASH_H
	#define XXHASH_H

	#include <linux/types.h>

	/-***************************
	* Simple Hash Functions
	*****************************/

	/**
	* xxh32() - calculate the 32-bit hash of the input with a given seed.
	*
	* @input: The data to hash.
	* @length: The length of the data to hash.
	* @seed: The seed can be used to alter the result predictably.
	*
	* Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
	*
	* Return: The 32-bit hash of the data.
	*/
	uint32_t xxh32(const void *input, size_t length, uint32_t seed);

	/**
	* xxh64() - calculate the 64-bit hash of the input with a given seed.
	*
	* @input: The data to hash.
	* @length: The length of the data to hash.
	* @seed: The seed can be used to alter the result predictably.
	*
	* This function runs 2x faster on 64-bit systems, but slower on 32-bit systems.
	*
	* Return: The 64-bit hash of the data.
	*/
	uint64_t xxh64(const void *input, size_t length, uint64_t seed);

	/**
	* xxhash() - calculate wordsize hash of the input with a given seed
	* @input: The data to hash.
	* @length: The length of the data to hash.
	* @seed: The seed can be used to alter the result predictably.
	*
	* If the hash does not need to be comparable between machines with
	* different word sizes, this function will call whichever of xxh32()
	* or xxh64() is faster.
	*
	* Return: wordsize hash of the data.
	*/

	static inline unsigned long xxhash(const void *input, size_t length,
	uint64_t seed)
	{
	#if BITS_PER_LONG == 64
	return xxh64(input, length, seed);
	#else
	return xxh32(input, length, seed);
	#endif
	}

	/-***************************
	* Streaming Hash Functions
	*****************************/

	/*
	* These definitions are only meant to allow allocation of XXH state
	* statically, on stack, or in a struct for example.
	* Do not use members directly.
	*/

	/**
	* struct xxh32_state - private xxh32 state, do not use members directly
	*/
	struct xxh32_state {
	uint32_t total_len_32;
	uint32_t large_len;
	uint32_t v1;
	uint32_t v2;
	uint32_t v3;
	uint32_t v4;
	uint32_t mem32[4];
	uint32_t memsize;
	};

	/**
	* struct xxh32_state - private xxh64 state, do not use members directly
	*/
	struct xxh64_state {
	uint64_t total_len;
	uint64_t v1;
	uint64_t v2;
	uint64_t v3;
	uint64_t v4;
	uint64_t mem64[4];
	uint32_t memsize;
	};

	/**
	* xxh32_reset() - reset the xxh32 state to start a new hashing operation
	*
	* @state: The xxh32 state to reset.
	* @seed: Initialize the hash state with this seed.
	*
	* Call this function on any xxh32_state to prepare for a new hashing operation.
	*/
	void xxh32_reset(struct xxh32_state *state, uint32_t seed);

	/**
	* xxh32_update() - hash the data given and update the xxh32 state
	*
	* @state: The xxh32 state to update.
	* @input: The data to hash.
	* @length: The length of the data to hash.
	*
	* After calling xxh32_reset() call xxh32_update() as many times as necessary.
	*
	* Return: Zero on success, otherwise an error code.
	*/
	int xxh32_update(struct xxh32_state state, const void input, size_t length);

	/**
	* xxh32_digest() - produce the current xxh32 hash
	*
	* @state: Produce the current xxh32 hash of this state.
	*
	* A hash value can be produced at any time. It is still possible to continue
	* inserting input into the hash state after a call to xxh32_digest(), and
	* generate new hashes later on, by calling xxh32_digest() again.
	*
	* Return: The xxh32 hash stored in the state.
	*/
	uint32_t xxh32_digest(const struct xxh32_state *state);

	/**
	* xxh64_reset() - reset the xxh64 state to start a new hashing operation
	*
	* @state: The xxh64 state to reset.
	* @seed: Initialize the hash state with this seed.
	*/
	void xxh64_reset(struct xxh64_state *state, uint64_t seed);

	/**
	* xxh64_update() - hash the data given and update the xxh64 state
	* @state: The xxh64 state to update.
	* @input: The data to hash.
	* @length: The length of the data to hash.
	*
	* After calling xxh64_reset() call xxh64_update() as many times as necessary.
	*
	* Return: Zero on success, otherwise an error code.
	*/
	int xxh64_update(struct xxh64_state state, const void input, size_t length);

	/**
	* xxh64_digest() - produce the current xxh64 hash
	*
	* @state: Produce the current xxh64 hash of this state.
	*
	* A hash value can be produced at any time. It is still possible to continue
	* inserting input into the hash state after a call to xxh64_digest(), and
	* generate new hashes later on, by calling xxh64_digest() again.
	*
	* Return: The xxh64 hash stored in the state.
	*/
	uint64_t xxh64_digest(const struct xxh64_state *state);

	/-*************************
	* Utils
	***************************/

	/**
	* xxh32_copy_state() - copy the source state into the destination state
	*
	* @src: The source xxh32 state.
	* @dst: The destination xxh32 state.
	*/
	void xxh32_copy_state(struct xxh32_state dst, const struct xxh32_state src);

	/**
	* xxh64_copy_state() - copy the source state into the destination state
	*
	* @src: The source xxh64 state.
	* @dst: The destination xxh64 state.
	*/
	void xxh64_copy_state(struct xxh64_state dst, const struct xxh64_state src);

	#endif /* XXHASH_H */