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1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___CXX03___FUNCTIONAL_HASH_H10#define _LIBCPP___CXX03___FUNCTIONAL_HASH_H11 12#include <__cxx03/__config>13#include <__cxx03/__functional/unary_function.h>14#include <__cxx03/__fwd/functional.h>15#include <__cxx03/__type_traits/conjunction.h>16#include <__cxx03/__type_traits/invoke.h>17#include <__cxx03/__type_traits/is_constructible.h>18#include <__cxx03/__type_traits/is_enum.h>19#include <__cxx03/__type_traits/underlying_type.h>20#include <__cxx03/__utility/pair.h>21#include <__cxx03/__utility/swap.h>22#include <__cxx03/cstddef>23#include <__cxx03/cstdint>24#include <__cxx03/cstring>25 26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)27# pragma GCC system_header28#endif29 30_LIBCPP_BEGIN_NAMESPACE_STD31 32template <class _Size>33inline _LIBCPP_HIDE_FROM_ABI _Size __loadword(const void* __p) {34 _Size __r;35 std::memcpy(&__r, __p, sizeof(__r));36 return __r;37}38 39// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t40// is 64 bits. This is because cityhash64 uses 64bit x 64bit41// multiplication, which can be very slow on 32-bit systems.42template <class _Size, size_t = sizeof(_Size) * __CHAR_BIT__>43struct __murmur2_or_cityhash;44 45template <class _Size>46struct __murmur2_or_cityhash<_Size, 32> {47 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK _Size48 operator()(const void* __key, _Size __len) const {49 // murmur250 const _Size __m = 0x5bd1e995;51 const _Size __r = 24;52 _Size __h = __len;53 const unsigned char* __data = static_cast<const unsigned char*>(__key);54 for (; __len >= 4; __data += 4, __len -= 4) {55 _Size __k = std::__loadword<_Size>(__data);56 __k *= __m;57 __k ^= __k >> __r;58 __k *= __m;59 __h *= __m;60 __h ^= __k;61 }62 switch (__len) {63 case 3:64 __h ^= static_cast<_Size>(__data[2] << 16);65 _LIBCPP_FALLTHROUGH();66 case 2:67 __h ^= static_cast<_Size>(__data[1] << 8);68 _LIBCPP_FALLTHROUGH();69 case 1:70 __h ^= __data[0];71 __h *= __m;72 }73 __h ^= __h >> 13;74 __h *= __m;75 __h ^= __h >> 15;76 return __h;77 }78};79 80template <class _Size>81struct __murmur2_or_cityhash<_Size, 64> {82 // cityhash6483 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK _Size84 operator()(const void* __key, _Size __len) const {85 const char* __s = static_cast<const char*>(__key);86 if (__len <= 32) {87 if (__len <= 16) {88 return __hash_len_0_to_16(__s, __len);89 } else {90 return __hash_len_17_to_32(__s, __len);91 }92 } else if (__len <= 64) {93 return __hash_len_33_to_64(__s, __len);94 }95 96 // For strings over 64 bytes we hash the end first, and then as we97 // loop we keep 56 bytes of state: v, w, x, y, and z.98 _Size __x = std::__loadword<_Size>(__s + __len - 40);99 _Size __y = std::__loadword<_Size>(__s + __len - 16) + std::__loadword<_Size>(__s + __len - 56);100 _Size __z =101 __hash_len_16(std::__loadword<_Size>(__s + __len - 48) + __len, std::__loadword<_Size>(__s + __len - 24));102 pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);103 pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);104 __x = __x * __k1 + std::__loadword<_Size>(__s);105 106 // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.107 __len = (__len - 1) & ~static_cast<_Size>(63);108 do {109 __x = __rotate(__x + __y + __v.first + std::__loadword<_Size>(__s + 8), 37) * __k1;110 __y = __rotate(__y + __v.second + std::__loadword<_Size>(__s + 48), 42) * __k1;111 __x ^= __w.second;112 __y += __v.first + std::__loadword<_Size>(__s + 40);113 __z = __rotate(__z + __w.first, 33) * __k1;114 __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);115 __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second, __y + std::__loadword<_Size>(__s + 16));116 std::swap(__z, __x);117 __s += 64;118 __len -= 64;119 } while (__len != 0);120 return __hash_len_16(__hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,121 __hash_len_16(__v.second, __w.second) + __x);122 }123 124private:125 // Some primes between 2^63 and 2^64.126 static const _Size __k0 = 0xc3a5c85c97cb3127ULL;127 static const _Size __k1 = 0xb492b66fbe98f273ULL;128 static const _Size __k2 = 0x9ae16a3b2f90404fULL;129 static const _Size __k3 = 0xc949d7c7509e6557ULL;130 131 _LIBCPP_HIDE_FROM_ABI static _Size __rotate(_Size __val, int __shift) {132 return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));133 }134 135 _LIBCPP_HIDE_FROM_ABI static _Size __rotate_by_at_least_1(_Size __val, int __shift) {136 return (__val >> __shift) | (__val << (64 - __shift));137 }138 139 _LIBCPP_HIDE_FROM_ABI static _Size __shift_mix(_Size __val) { return __val ^ (__val >> 47); }140 141 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK static _Size __hash_len_16(_Size __u, _Size __v) {142 const _Size __mul = 0x9ddfea08eb382d69ULL;143 _Size __a = (__u ^ __v) * __mul;144 __a ^= (__a >> 47);145 _Size __b = (__v ^ __a) * __mul;146 __b ^= (__b >> 47);147 __b *= __mul;148 return __b;149 }150 151 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK static _Size152 __hash_len_0_to_16(const char* __s, _Size __len) {153 if (__len > 8) {154 const _Size __a = std::__loadword<_Size>(__s);155 const _Size __b = std::__loadword<_Size>(__s + __len - 8);156 return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;157 }158 if (__len >= 4) {159 const uint32_t __a = std::__loadword<uint32_t>(__s);160 const uint32_t __b = std::__loadword<uint32_t>(__s + __len - 4);161#ifdef _LIBCPP_ABI_FIX_CITYHASH_IMPLEMENTATION162 return __hash_len_16(__len + (static_cast<_Size>(__a) << 3), __b);163#else164 return __hash_len_16(__len + (__a << 3), __b);165#endif166 }167 if (__len > 0) {168 const unsigned char __a = static_cast<unsigned char>(__s[0]);169 const unsigned char __b = static_cast<unsigned char>(__s[__len >> 1]);170 const unsigned char __c = static_cast<unsigned char>(__s[__len - 1]);171 const uint32_t __y = static_cast<uint32_t>(__a) + (static_cast<uint32_t>(__b) << 8);172 const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);173 return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;174 }175 return __k2;176 }177 178 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK static _Size179 __hash_len_17_to_32(const char* __s, _Size __len) {180 const _Size __a = std::__loadword<_Size>(__s) * __k1;181 const _Size __b = std::__loadword<_Size>(__s + 8);182 const _Size __c = std::__loadword<_Size>(__s + __len - 8) * __k2;183 const _Size __d = std::__loadword<_Size>(__s + __len - 16) * __k0;184 return __hash_len_16(185 __rotate(__a - __b, 43) + __rotate(__c, 30) + __d, __a + __rotate(__b ^ __k3, 20) - __c + __len);186 }187 188 // Return a 16-byte hash for 48 bytes. Quick and dirty.189 // Callers do best to use "random-looking" values for a and b.190 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK static pair<_Size, _Size>191 __weak_hash_len_32_with_seeds(_Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b) {192 __a += __w;193 __b = __rotate(__b + __a + __z, 21);194 const _Size __c = __a;195 __a += __x;196 __a += __y;197 __b += __rotate(__a, 44);198 return pair<_Size, _Size>(__a + __z, __b + __c);199 }200 201 // Return a 16-byte hash for s[0] ... s[31], a, and b. Quick and dirty.202 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK static pair<_Size, _Size>203 __weak_hash_len_32_with_seeds(const char* __s, _Size __a, _Size __b) {204 return __weak_hash_len_32_with_seeds(205 std::__loadword<_Size>(__s),206 std::__loadword<_Size>(__s + 8),207 std::__loadword<_Size>(__s + 16),208 std::__loadword<_Size>(__s + 24),209 __a,210 __b);211 }212 213 // Return an 8-byte hash for 33 to 64 bytes.214 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK static _Size215 __hash_len_33_to_64(const char* __s, size_t __len) {216 _Size __z = std::__loadword<_Size>(__s + 24);217 _Size __a = std::__loadword<_Size>(__s) + (__len + std::__loadword<_Size>(__s + __len - 16)) * __k0;218 _Size __b = __rotate(__a + __z, 52);219 _Size __c = __rotate(__a, 37);220 __a += std::__loadword<_Size>(__s + 8);221 __c += __rotate(__a, 7);222 __a += std::__loadword<_Size>(__s + 16);223 _Size __vf = __a + __z;224 _Size __vs = __b + __rotate(__a, 31) + __c;225 __a = std::__loadword<_Size>(__s + 16) + std::__loadword<_Size>(__s + __len - 32);226 __z += std::__loadword<_Size>(__s + __len - 8);227 __b = __rotate(__a + __z, 52);228 __c = __rotate(__a, 37);229 __a += std::__loadword<_Size>(__s + __len - 24);230 __c += __rotate(__a, 7);231 __a += std::__loadword<_Size>(__s + __len - 16);232 _Size __wf = __a + __z;233 _Size __ws = __b + __rotate(__a, 31) + __c;234 _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);235 return __shift_mix(__r * __k0 + __vs) * __k2;236 }237};238 239template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>240struct __scalar_hash;241 242template <class _Tp>243struct __scalar_hash<_Tp, 0> : public __unary_function<_Tp, size_t> {244 _LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT {245 union {246 _Tp __t;247 size_t __a;248 } __u;249 __u.__a = 0;250 __u.__t = __v;251 return __u.__a;252 }253};254 255template <class _Tp>256struct __scalar_hash<_Tp, 1> : public __unary_function<_Tp, size_t> {257 _LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT {258 union {259 _Tp __t;260 size_t __a;261 } __u;262 __u.__t = __v;263 return __u.__a;264 }265};266 267template <class _Tp>268struct __scalar_hash<_Tp, 2> : public __unary_function<_Tp, size_t> {269 _LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT {270 union {271 _Tp __t;272 struct {273 size_t __a;274 size_t __b;275 } __s;276 } __u;277 __u.__t = __v;278 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));279 }280};281 282template <class _Tp>283struct __scalar_hash<_Tp, 3> : public __unary_function<_Tp, size_t> {284 _LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT {285 union {286 _Tp __t;287 struct {288 size_t __a;289 size_t __b;290 size_t __c;291 } __s;292 } __u;293 __u.__t = __v;294 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));295 }296};297 298template <class _Tp>299struct __scalar_hash<_Tp, 4> : public __unary_function<_Tp, size_t> {300 _LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT {301 union {302 _Tp __t;303 struct {304 size_t __a;305 size_t __b;306 size_t __c;307 size_t __d;308 } __s;309 } __u;310 __u.__t = __v;311 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));312 }313};314 315struct _PairT {316 size_t first;317 size_t second;318};319 320_LIBCPP_HIDE_FROM_ABI inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {321 typedef __scalar_hash<_PairT> _HashT;322 const _PairT __p = {__lhs, __rhs};323 return _HashT()(__p);324}325 326template <class _Tp>327struct _LIBCPP_TEMPLATE_VIS hash<_Tp*> : public __unary_function<_Tp*, size_t> {328 _LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp* __v) const _NOEXCEPT {329 union {330 _Tp* __t;331 size_t __a;332 } __u;333 __u.__t = __v;334 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));335 }336};337 338template <>339struct _LIBCPP_TEMPLATE_VIS hash<bool> : public __unary_function<bool, size_t> {340 _LIBCPP_HIDE_FROM_ABI size_t operator()(bool __v) const _NOEXCEPT { return static_cast<size_t>(__v); }341};342 343template <>344struct _LIBCPP_TEMPLATE_VIS hash<char> : public __unary_function<char, size_t> {345 _LIBCPP_HIDE_FROM_ABI size_t operator()(char __v) const _NOEXCEPT { return static_cast<size_t>(__v); }346};347 348template <>349struct _LIBCPP_TEMPLATE_VIS hash<signed char> : public __unary_function<signed char, size_t> {350 _LIBCPP_HIDE_FROM_ABI size_t operator()(signed char __v) const _NOEXCEPT { return static_cast<size_t>(__v); }351};352 353template <>354struct _LIBCPP_TEMPLATE_VIS hash<unsigned char> : public __unary_function<unsigned char, size_t> {355 _LIBCPP_HIDE_FROM_ABI size_t operator()(unsigned char __v) const _NOEXCEPT { return static_cast<size_t>(__v); }356};357 358#ifndef _LIBCPP_HAS_NO_CHAR8_T359template <>360struct _LIBCPP_TEMPLATE_VIS hash<char8_t> : public __unary_function<char8_t, size_t> {361 _LIBCPP_HIDE_FROM_ABI size_t operator()(char8_t __v) const _NOEXCEPT { return static_cast<size_t>(__v); }362};363#endif // !_LIBCPP_HAS_NO_CHAR8_T364 365template <>366struct _LIBCPP_TEMPLATE_VIS hash<char16_t> : public __unary_function<char16_t, size_t> {367 _LIBCPP_HIDE_FROM_ABI size_t operator()(char16_t __v) const _NOEXCEPT { return static_cast<size_t>(__v); }368};369 370template <>371struct _LIBCPP_TEMPLATE_VIS hash<char32_t> : public __unary_function<char32_t, size_t> {372 _LIBCPP_HIDE_FROM_ABI size_t operator()(char32_t __v) const _NOEXCEPT { return static_cast<size_t>(__v); }373};374 375#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS376template <>377struct _LIBCPP_TEMPLATE_VIS hash<wchar_t> : public __unary_function<wchar_t, size_t> {378 _LIBCPP_HIDE_FROM_ABI size_t operator()(wchar_t __v) const _NOEXCEPT { return static_cast<size_t>(__v); }379};380#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS381 382template <>383struct _LIBCPP_TEMPLATE_VIS hash<short> : public __unary_function<short, size_t> {384 _LIBCPP_HIDE_FROM_ABI size_t operator()(short __v) const _NOEXCEPT { return static_cast<size_t>(__v); }385};386 387template <>388struct _LIBCPP_TEMPLATE_VIS hash<unsigned short> : public __unary_function<unsigned short, size_t> {389 _LIBCPP_HIDE_FROM_ABI size_t operator()(unsigned short __v) const _NOEXCEPT { return static_cast<size_t>(__v); }390};391 392template <>393struct _LIBCPP_TEMPLATE_VIS hash<int> : public __unary_function<int, size_t> {394 _LIBCPP_HIDE_FROM_ABI size_t operator()(int __v) const _NOEXCEPT { return static_cast<size_t>(__v); }395};396 397template <>398struct _LIBCPP_TEMPLATE_VIS hash<unsigned int> : public __unary_function<unsigned int, size_t> {399 _LIBCPP_HIDE_FROM_ABI size_t operator()(unsigned int __v) const _NOEXCEPT { return static_cast<size_t>(__v); }400};401 402template <>403struct _LIBCPP_TEMPLATE_VIS hash<long> : public __unary_function<long, size_t> {404 _LIBCPP_HIDE_FROM_ABI size_t operator()(long __v) const _NOEXCEPT { return static_cast<size_t>(__v); }405};406 407template <>408struct _LIBCPP_TEMPLATE_VIS hash<unsigned long> : public __unary_function<unsigned long, size_t> {409 _LIBCPP_HIDE_FROM_ABI size_t operator()(unsigned long __v) const _NOEXCEPT { return static_cast<size_t>(__v); }410};411 412template <>413struct _LIBCPP_TEMPLATE_VIS hash<long long> : public __scalar_hash<long long> {};414 415template <>416struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long> : public __scalar_hash<unsigned long long> {};417 418#ifndef _LIBCPP_HAS_NO_INT128419 420template <>421struct _LIBCPP_TEMPLATE_VIS hash<__int128_t> : public __scalar_hash<__int128_t> {};422 423template <>424struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t> : public __scalar_hash<__uint128_t> {};425 426#endif427 428template <>429struct _LIBCPP_TEMPLATE_VIS hash<float> : public __scalar_hash<float> {430 _LIBCPP_HIDE_FROM_ABI size_t operator()(float __v) const _NOEXCEPT {431 // -0.0 and 0.0 should return same hash432 if (__v == 0.0f)433 return 0;434 return __scalar_hash<float>::operator()(__v);435 }436};437 438template <>439struct _LIBCPP_TEMPLATE_VIS hash<double> : public __scalar_hash<double> {440 _LIBCPP_HIDE_FROM_ABI size_t operator()(double __v) const _NOEXCEPT {441 // -0.0 and 0.0 should return same hash442 if (__v == 0.0)443 return 0;444 return __scalar_hash<double>::operator()(__v);445 }446};447 448template <>449struct _LIBCPP_TEMPLATE_VIS hash<long double> : public __scalar_hash<long double> {450 _LIBCPP_HIDE_FROM_ABI size_t operator()(long double __v) const _NOEXCEPT {451 // -0.0 and 0.0 should return same hash452 if (__v == 0.0L)453 return 0;454#if defined(__i386__) || (defined(__x86_64__) && defined(__ILP32__))455 // Zero out padding bits456 union {457 long double __t;458 struct {459 size_t __a;460 size_t __b;461 size_t __c;462 size_t __d;463 } __s;464 } __u;465 __u.__s.__a = 0;466 __u.__s.__b = 0;467 __u.__s.__c = 0;468 __u.__s.__d = 0;469 __u.__t = __v;470 return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;471#elif defined(__x86_64__)472 // Zero out padding bits473 union {474 long double __t;475 struct {476 size_t __a;477 size_t __b;478 } __s;479 } __u;480 __u.__s.__a = 0;481 __u.__s.__b = 0;482 __u.__t = __v;483 return __u.__s.__a ^ __u.__s.__b;484#else485 return __scalar_hash<long double>::operator()(__v);486#endif487 }488};489 490template <class _Tp, bool = is_enum<_Tp>::value>491struct _LIBCPP_TEMPLATE_VIS __enum_hash : public __unary_function<_Tp, size_t> {492 _LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT {493 typedef typename underlying_type<_Tp>::type type;494 return hash<type>()(static_cast<type>(__v));495 }496};497template <class _Tp>498struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {499 __enum_hash() = delete;500 __enum_hash(__enum_hash const&) = delete;501 __enum_hash& operator=(__enum_hash const&) = delete;502};503 504template <class _Tp>505struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp> {};506 507_LIBCPP_END_NAMESPACE_STD508 509#endif // _LIBCPP___CXX03___FUNCTIONAL_HASH_H510