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aka_str_hash.hh
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/**
* @file aka_str_hash.hh
*
* @author Nicolas Richart
*
* @date creation lun déc 09 2019
*
* @brief A Documented file.
*
* @section LICENSE
*
* Copyright (©) 2010-2011 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* akantu-iterators is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.
*
* akantu-iterators is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with akantu-iterators. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include <cstddef>
#include <cstdint>
#include <type_traits>
#include <initializer_list>
/* -------------------------------------------------------------------------- */
#ifndef AKANTU_AKA_STR_HASH_HH
#define AKANTU_AKA_STR_HASH_HH
#ifndef AKANTU_ITERATORS_NAMESPACE
#define AKANTU_ITERATORS_NAMESPACE akantu
#endif
namespace AKANTU_ITERATORS_NAMESPACE {
namespace hash {
namespace details {
// CRC32 Table (zlib polynomial)
static constexpr uint32_t crc_table[256] = {
0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
0x2d02ef8dL};
/* --------------------------------------------------------------------------
*/
/// CRC32 hashing algorithm
constexpr uint32_t crc32_hash(const char * str, size_t idx) {
auto crc = (idx == 0 ? 0xFFFFFFFF : crc32_hash(str, idx - 1));
return (crc >> 8) ^ crc_table[(crc ^ str[idx]) & 0x000000FF];
}
namespace {
template <typename Hash> constexpr Hash fnv1a_offset = 0x0;
template <>
constexpr uint64_t fnv1a_offset<uint64_t> = 0xcbf29ce484222325;
template <> constexpr uint32_t fnv1a_offset<uint32_t> = 0x811c9dc5;
template <typename Hash> constexpr Hash fnv1a_prime = 0x0;
template <> constexpr uint64_t fnv1a_prime<uint64_t> = 0x00000100000001b3;
template <> constexpr uint32_t fnv1a_prime<uint32_t> = 0x01000193;
} // namespace
template <class T, T offset = fnv1a_offset<T>, T prime = fnv1a_prime<T>>
constexpr T fnv1a_hash(const char * str, size_t idx) {
return ((idx ? fnv1a_hash<T, offset, prime>(str, idx - 1) : offset) ^
str[idx]) *
prime;
}
// FNV-1a 32bit hashing algorithm.
constexpr decltype(auto) fnv1a_32_hash(const char * str, size_t idx) {
return fnv1a_hash<uint32_t>(str, idx);
}
// FNV-1a 32bit hashing algorithm.
constexpr decltype(auto) fnv1a_64_hash(const char * str, size_t idx) {
return fnv1a_hash<uint64_t>(str, idx);
}
template <typename Hash, typename CharT, CharT... chars>
constexpr Hash fnv1a() {
auto result = fnv1a_offset<Hash>;
(void)std::initializer_list<Hash>{
(result = (result ^ chars) * fnv1a_prime<Hash>, Hash{})...};
return result;
}
} // namespace details
constexpr uint32_t operator"" _crc32(const char * str, size_t size) {
return details::crc32_hash(str, size - 1) ^ 0xFFFFFFFF;
}
constexpr uint32_t operator"" _fnv1a32(const char * str, size_t size) {
return details::fnv1a_32_hash(str, size - 1);
}
constexpr uint64_t operator"" _fnv1a64(const char * str, size_t size) {
return details::fnv1a_64_hash(str, size - 1);
}
} // namespace hash
template <typename CharT, CharT... chars> struct string_literal {
static constexpr uint64_t hash =
hash::details::fnv1a<uint64_t, CharT, chars...>();
using hash_type = std::integral_constant<uint64_t, hash>;
};
template <typename CharT, CharT... chars>
constexpr uint64_t string_literal<CharT, chars...>::hash;
constexpr auto operator"" _h(const char * str, size_t size) {
return hash::details::fnv1a_64_hash(str, size - 1);
}
} // namespace AKANTU_ITERATOR_NAMESPACE
#endif /* AKANTU_AKA_STR_HASH_HH */

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