/*
* xxHash - Extremely Fast Hash algorithm
* Header File
* Copyright (C) 2012-2021 Yann Collet
*
* BSD 2-Clause License (https://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.
*
* You can contact the author at:
* - xxHash homepage: https://www.xxhash.com
* - xxHash source repository: https://github.com/Cyan4973/xxHash
*/
/*!
* @mainpage xxHash
*
* xxHash is an extremely fast non-cryptographic hash algorithm, working at RAM speed
* limits.
*
* It is proposed in four flavors, in three families:
* 1. @ref XXH32_family
* - Classic 32-bit hash function. Simple, compact, and runs on almost all
* 32-bit and 64-bit systems.
* 2. @ref XXH64_family
* - Classic 64-bit adaptation of XXH32. Just as simple, and runs well on most
* 64-bit systems (but _not_ 32-bit systems).
* 3. @ref XXH3_family
* - Modern 64-bit and 128-bit hash function family which features improved
* strength and performance across the board, especially on smaller data.
* It benefits greatly from SIMD and 64-bit without requiring it.
*
* Benchmarks
* ---
* The reference system uses an Intel i7-9700K CPU, and runs Ubuntu x64 20.04.
* The open source benchmark program is compiled with clang v10.0 using -O3 flag.
*
* | Hash Name | ISA ext | Width | Large Data Speed | Small Data Velocity |
* | -------------------- | ------- | ----: | ---------------: | ------------------: |
* | XXH3_64bits() | @b AVX2 | 64 | 59.4 GB/s | 133.1 |
* | MeowHash | AES-NI | 128 | 58.2 GB/s | 52.5 |
* | XXH3_128bits() | @b AVX2 | 128 | 57.9 GB/s | 118.1 |
* | CLHash | PCLMUL | 64 | 37.1 GB/s | 58.1 |
* | XXH3_64bits() | @b SSE2 | 64 | 31.5 GB/s | 133.1 |
* | XXH3_128bits() | @b SSE2 | 128 | 29.6 GB/s | 118.1 |
* | RAM sequential read | | N/A | 28.0 GB/s | N/A |
* | ahash | AES-NI | 64 | 22.5 GB/s | 107.2 |
* | City64 | | 64 | 22.0 GB/s | 76.6 |
* | T1ha2 | | 64 | 22.0 GB/s | 99.0 |
* | City128 | | 128 | 21.7 GB/s | 57.7 |
* | FarmHash | AES-NI | 64 | 21.3 GB/s | 71.9 |
* | XXH64() | | 64 | 19.4 GB/s | 71.0 |
* | SpookyHash | | 64 | 19.3 GB/s | 53.2 |
* | Mum | | 64 | 18.0 GB/s | 67.0 |
* | CRC32C | SSE4.2 | 32 | 13.0 GB/s | 57.9 |
* | XXH32() | | 32 | 9.7 GB/s | 71.9 |
* | City32 | | 32 | 9.1 GB/s | 66.0 |
* | Blake3* | @b AVX2 | 256 | 4.4 GB/s | 8.1 |
* | Murmur3 | | 32 | 3.9 GB/s | 56.1 |
* | SipHash* | | 64 | 3.0 GB/s | 43.2 |
* | Blake3* | @b SSE2 | 256 | 2.4 GB/s | 8.1 |
* | HighwayHash | | 64 | 1.4 GB/s | 6.0 |
* | FNV64 | | 64 | 1.2 GB/s | 62.7 |
* | Blake2* | | 256 | 1.1 GB/s | 5.1 |
* | SHA1* | | 160 | 0.8 GB/s | 5.6 |
* | MD5* | | 128 | 0.6 GB/s | 7.8 |
* @note
* - Hashes which require a specific ISA extension are noted. SSE2 is also noted,
* even though it is mandatory on x64.
* - Hashes with an asterisk are cryptographic. Note that MD5 is non-cryptographic
* by modern standards.
* - Small data velocity is a rough average of algorithm's efficiency for small
* data. For more accurate information, see the wiki.
* - More benchmarks and strength tests are found on the wiki:
* https://github.com/Cyan4973/xxHash/wiki
*
* Usage
* ------
* All xxHash variants use a similar API. Changing the algorithm is a trivial
* substitution.
*
* @pre
* For functions which take an input and length parameter, the following
* requirements are assumed:
* - The range from [`input`, `input + length`) is valid, readable memory.
* - The only exception is if the `length` is `0`, `input` may be `NULL`.
* - For C++, the objects must have the *TriviallyCopyable* property, as the
* functions access bytes directly as if it was an array of `unsigned char`.
*
* @anchor single_shot_example
* **Single Shot**
*
* These functions are stateless functions which hash a contiguous block of memory,
* immediately returning the result. They are the easiest and usually the fastest
* option.
*
* XXH32(), XXH64(), XXH3_64bits(), XXH3_128bits()
*
* @code{.c}
* #include
* #include "xxhash.h"
*
* // Example for a function which hashes a null terminated string with XXH32().
* XXH32_hash_t hash_string(const char* string, XXH32_hash_t seed)
* {
* // NULL pointers are only valid if the length is zero
* size_t length = (string == NULL) ? 0 : strlen(string);
* return XXH32(string, length, seed);
* }
* @endcode
*
* @anchor streaming_example
* **Streaming**
*
* These groups of functions allow incremental hashing of unknown size, even
* more than what would fit in a size_t.
*
* XXH32_reset(), XXH64_reset(), XXH3_64bits_reset(), XXH3_128bits_reset()
*
* @code{.c}
* #include
* #include
* #include "xxhash.h"
* // Example for a function which hashes a FILE incrementally with XXH3_64bits().
* XXH64_hash_t hashFile(FILE* f)
* {
* // Allocate a state struct. Do not just use malloc() or new.
* XXH3_state_t* state = XXH3_createState();
* assert(state != NULL && "Out of memory!");
* // Reset the state to start a new hashing session.
* XXH3_64bits_reset(state);
* char buffer[4096];
* size_t count;
* // Read the file in chunks
* while ((count = fread(buffer, 1, sizeof(buffer), f)) != 0) {
* // Run update() as many times as necessary to process the data
* XXH3_