1 //===----------------------------------------------------------------------===//
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-exception
7 //===----------------------------------------------------------------------===//
9 #ifndef _LIBCPP___FUNCTIONAL_HASH_H
10 #define _LIBCPP___FUNCTIONAL_HASH_H
13 #include <__functional/invoke.h>
14 #include <__functional/unary_function.h>
15 #include <__fwd/hash.h>
16 #include <__tuple/sfinae_helpers.h>
17 #include <__type_traits/is_copy_constructible.h>
18 #include <__type_traits/is_default_constructible.h>
19 #include <__type_traits/is_enum.h>
20 #include <__type_traits/is_move_constructible.h>
21 #include <__type_traits/underlying_type.h>
22 #include <__utility/forward.h>
23 #include <__utility/move.h>
24 #include <__utility/pair.h>
25 #include <__utility/swap.h>
31 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
32 # pragma GCC system_header
35 _LIBCPP_BEGIN_NAMESPACE_STD
37 template <class _Size>
38 inline _LIBCPP_HIDE_FROM_ABI
40 __loadword(const void* __p)
43 _VSTD::memcpy(&__r, __p, sizeof(__r));
47 // We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
48 // is 64 bits. This is because cityhash64 uses 64bit x 64bit
49 // multiplication, which can be very slow on 32-bit systems.
50 template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
51 struct __murmur2_or_cityhash;
53 template <class _Size>
54 struct __murmur2_or_cityhash<_Size, 32>
56 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
57 _Size operator()(const void* __key, _Size __len) const {
59 const _Size __m = 0x5bd1e995;
62 const unsigned char* __data = static_cast<const unsigned char*>(__key);
63 for (; __len >= 4; __data += 4, __len -= 4)
65 _Size __k = std::__loadword<_Size>(__data);
75 __h ^= static_cast<_Size>(__data[2] << 16);
76 _LIBCPP_FALLTHROUGH();
78 __h ^= static_cast<_Size>(__data[1] << 8);
79 _LIBCPP_FALLTHROUGH();
91 template <class _Size>
92 struct __murmur2_or_cityhash<_Size, 64>
95 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
96 _Size operator()(const void* __key, _Size __len) const {
97 const char* __s = static_cast<const char*>(__key);
100 return __hash_len_0_to_16(__s, __len);
102 return __hash_len_17_to_32(__s, __len);
104 } else if (__len <= 64) {
105 return __hash_len_33_to_64(__s, __len);
108 // For strings over 64 bytes we hash the end first, and then as we
109 // loop we keep 56 bytes of state: v, w, x, y, and z.
110 _Size __x = std::__loadword<_Size>(__s + __len - 40);
111 _Size __y = std::__loadword<_Size>(__s + __len - 16) +
112 std::__loadword<_Size>(__s + __len - 56);
113 _Size __z = __hash_len_16(std::__loadword<_Size>(__s + __len - 48) + __len,
114 std::__loadword<_Size>(__s + __len - 24));
115 pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
116 pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
117 __x = __x * __k1 + std::__loadword<_Size>(__s);
119 // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
120 __len = (__len - 1) & ~static_cast<_Size>(63);
122 __x = __rotate(__x + __y + __v.first + std::__loadword<_Size>(__s + 8), 37) * __k1;
123 __y = __rotate(__y + __v.second + std::__loadword<_Size>(__s + 48), 42) * __k1;
125 __y += __v.first + std::__loadword<_Size>(__s + 40);
126 __z = __rotate(__z + __w.first, 33) * __k1;
127 __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
128 __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
129 __y + std::__loadword<_Size>(__s + 16));
130 _VSTD::swap(__z, __x);
133 } while (__len != 0);
134 return __hash_len_16(
135 __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
136 __hash_len_16(__v.second, __w.second) + __x);
140 // Some primes between 2^63 and 2^64.
141 static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
142 static const _Size __k1 = 0xb492b66fbe98f273ULL;
143 static const _Size __k2 = 0x9ae16a3b2f90404fULL;
144 static const _Size __k3 = 0xc949d7c7509e6557ULL;
146 _LIBCPP_HIDE_FROM_ABI
147 static _Size __rotate(_Size __val, int __shift) {
148 return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
151 _LIBCPP_HIDE_FROM_ABI
152 static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
153 return (__val >> __shift) | (__val << (64 - __shift));
156 _LIBCPP_HIDE_FROM_ABI
157 static _Size __shift_mix(_Size __val) {
158 return __val ^ (__val >> 47);
161 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
162 static _Size __hash_len_16(_Size __u, _Size __v) {
163 const _Size __mul = 0x9ddfea08eb382d69ULL;
164 _Size __a = (__u ^ __v) * __mul;
166 _Size __b = (__v ^ __a) * __mul;
172 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
173 static _Size __hash_len_0_to_16(const char* __s, _Size __len) {
175 const _Size __a = std::__loadword<_Size>(__s);
176 const _Size __b = std::__loadword<_Size>(__s + __len - 8);
177 return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
180 const uint32_t __a = std::__loadword<uint32_t>(__s);
181 const uint32_t __b = std::__loadword<uint32_t>(__s + __len - 4);
182 #ifdef _LIBCPP_ABI_FIX_CITYHASH_IMPLEMENTATION
183 return __hash_len_16(__len + (static_cast<_Size>(__a) << 3), __b);
185 return __hash_len_16(__len + (__a << 3), __b);
189 const unsigned char __a = static_cast<unsigned char>(__s[0]);
190 const unsigned char __b = static_cast<unsigned char>(__s[__len >> 1]);
191 const unsigned char __c = static_cast<unsigned char>(__s[__len - 1]);
192 const uint32_t __y = static_cast<uint32_t>(__a) +
193 (static_cast<uint32_t>(__b) << 8);
194 const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
195 return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
200 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
201 static _Size __hash_len_17_to_32(const char *__s, _Size __len) {
202 const _Size __a = std::__loadword<_Size>(__s) * __k1;
203 const _Size __b = std::__loadword<_Size>(__s + 8);
204 const _Size __c = std::__loadword<_Size>(__s + __len - 8) * __k2;
205 const _Size __d = std::__loadword<_Size>(__s + __len - 16) * __k0;
206 return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
207 __a + __rotate(__b ^ __k3, 20) - __c + __len);
210 // Return a 16-byte hash for 48 bytes. Quick and dirty.
211 // Callers do best to use "random-looking" values for a and b.
212 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
213 static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
214 _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
217 __b = __rotate(__b + __a + __z, 21);
218 const _Size __c = __a;
221 __b += __rotate(__a, 44);
222 return pair<_Size, _Size>(__a + __z, __b + __c);
225 // Return a 16-byte hash for s[0] ... s[31], a, and b. Quick and dirty.
226 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
227 static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
228 const char* __s, _Size __a, _Size __b)
230 return __weak_hash_len_32_with_seeds(std::__loadword<_Size>(__s),
231 std::__loadword<_Size>(__s + 8),
232 std::__loadword<_Size>(__s + 16),
233 std::__loadword<_Size>(__s + 24),
238 // Return an 8-byte hash for 33 to 64 bytes.
239 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
240 static _Size __hash_len_33_to_64(const char *__s, size_t __len) {
241 _Size __z = std::__loadword<_Size>(__s + 24);
242 _Size __a = std::__loadword<_Size>(__s) +
243 (__len + std::__loadword<_Size>(__s + __len - 16)) * __k0;
244 _Size __b = __rotate(__a + __z, 52);
245 _Size __c = __rotate(__a, 37);
246 __a += std::__loadword<_Size>(__s + 8);
247 __c += __rotate(__a, 7);
248 __a += std::__loadword<_Size>(__s + 16);
249 _Size __vf = __a + __z;
250 _Size __vs = __b + __rotate(__a, 31) + __c;
251 __a = std::__loadword<_Size>(__s + 16) + std::__loadword<_Size>(__s + __len - 32);
252 __z += std::__loadword<_Size>(__s + __len - 8);
253 __b = __rotate(__a + __z, 52);
254 __c = __rotate(__a, 37);
255 __a += std::__loadword<_Size>(__s + __len - 24);
256 __c += __rotate(__a, 7);
257 __a += std::__loadword<_Size>(__s + __len - 16);
258 _Size __wf = __a + __z;
259 _Size __ws = __b + __rotate(__a, 31) + __c;
260 _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
261 return __shift_mix(__r * __k0 + __vs) * __k2;
265 template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
266 struct __scalar_hash;
269 struct __scalar_hash<_Tp, 0>
270 : public __unary_function<_Tp, size_t>
272 _LIBCPP_HIDE_FROM_ABI
273 size_t operator()(_Tp __v) const _NOEXCEPT
287 struct __scalar_hash<_Tp, 1>
288 : public __unary_function<_Tp, size_t>
290 _LIBCPP_HIDE_FROM_ABI
291 size_t operator()(_Tp __v) const _NOEXCEPT
304 struct __scalar_hash<_Tp, 2>
305 : public __unary_function<_Tp, size_t>
307 _LIBCPP_HIDE_FROM_ABI
308 size_t operator()(_Tp __v) const _NOEXCEPT
320 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
325 struct __scalar_hash<_Tp, 3>
326 : public __unary_function<_Tp, size_t>
328 _LIBCPP_HIDE_FROM_ABI
329 size_t operator()(_Tp __v) const _NOEXCEPT
342 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
347 struct __scalar_hash<_Tp, 4>
348 : public __unary_function<_Tp, size_t>
350 _LIBCPP_HIDE_FROM_ABI
351 size_t operator()(_Tp __v) const _NOEXCEPT
365 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
374 _LIBCPP_HIDE_FROM_ABI
375 inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
376 typedef __scalar_hash<_PairT> _HashT;
377 const _PairT __p = {__lhs, __rhs};
378 return _HashT()(__p);
382 struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
383 : public __unary_function<_Tp*, size_t>
385 _LIBCPP_HIDE_FROM_ABI
386 size_t operator()(_Tp* __v) const _NOEXCEPT
394 return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
399 struct _LIBCPP_TEMPLATE_VIS hash<bool>
400 : public __unary_function<bool, size_t>
402 _LIBCPP_HIDE_FROM_ABI
403 size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
407 struct _LIBCPP_TEMPLATE_VIS hash<char>
408 : public __unary_function<char, size_t>
410 _LIBCPP_HIDE_FROM_ABI
411 size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
415 struct _LIBCPP_TEMPLATE_VIS hash<signed char>
416 : public __unary_function<signed char, size_t>
418 _LIBCPP_HIDE_FROM_ABI
419 size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
423 struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
424 : public __unary_function<unsigned char, size_t>
426 _LIBCPP_HIDE_FROM_ABI
427 size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
430 #ifndef _LIBCPP_HAS_NO_CHAR8_T
432 struct _LIBCPP_TEMPLATE_VIS hash<char8_t>
433 : public __unary_function<char8_t, size_t>
435 _LIBCPP_HIDE_FROM_ABI
436 size_t operator()(char8_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
438 #endif // !_LIBCPP_HAS_NO_CHAR8_T
441 struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
442 : public __unary_function<char16_t, size_t>
444 _LIBCPP_HIDE_FROM_ABI
445 size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
449 struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
450 : public __unary_function<char32_t, size_t>
452 _LIBCPP_HIDE_FROM_ABI
453 size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
456 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
458 struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
459 : public __unary_function<wchar_t, size_t>
461 _LIBCPP_HIDE_FROM_ABI
462 size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
464 #endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
467 struct _LIBCPP_TEMPLATE_VIS hash<short>
468 : public __unary_function<short, size_t>
470 _LIBCPP_HIDE_FROM_ABI
471 size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
475 struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
476 : public __unary_function<unsigned short, size_t>
478 _LIBCPP_HIDE_FROM_ABI
479 size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
483 struct _LIBCPP_TEMPLATE_VIS hash<int>
484 : public __unary_function<int, size_t>
486 _LIBCPP_HIDE_FROM_ABI
487 size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
491 struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
492 : public __unary_function<unsigned int, size_t>
494 _LIBCPP_HIDE_FROM_ABI
495 size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
499 struct _LIBCPP_TEMPLATE_VIS hash<long>
500 : public __unary_function<long, size_t>
502 _LIBCPP_HIDE_FROM_ABI
503 size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
507 struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
508 : public __unary_function<unsigned long, size_t>
510 _LIBCPP_HIDE_FROM_ABI
511 size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
515 struct _LIBCPP_TEMPLATE_VIS hash<long long>
516 : public __scalar_hash<long long>
521 struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
522 : public __scalar_hash<unsigned long long>
526 #ifndef _LIBCPP_HAS_NO_INT128
529 struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
530 : public __scalar_hash<__int128_t>
535 struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
536 : public __scalar_hash<__uint128_t>
543 struct _LIBCPP_TEMPLATE_VIS hash<float>
544 : public __scalar_hash<float>
546 _LIBCPP_HIDE_FROM_ABI
547 size_t operator()(float __v) const _NOEXCEPT
549 // -0.0 and 0.0 should return same hash
552 return __scalar_hash<float>::operator()(__v);
557 struct _LIBCPP_TEMPLATE_VIS hash<double>
558 : public __scalar_hash<double>
560 _LIBCPP_HIDE_FROM_ABI
561 size_t operator()(double __v) const _NOEXCEPT
563 // -0.0 and 0.0 should return same hash
566 return __scalar_hash<double>::operator()(__v);
571 struct _LIBCPP_TEMPLATE_VIS hash<long double>
572 : public __scalar_hash<long double>
574 _LIBCPP_HIDE_FROM_ABI
575 size_t operator()(long double __v) const _NOEXCEPT
577 // -0.0 and 0.0 should return same hash
580 #if defined(__i386__) || (defined(__x86_64__) && defined(__ILP32__))
581 // Zero out padding bits
598 return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
599 #elif defined(__x86_64__)
600 // Zero out padding bits
613 return __u.__s.__a ^ __u.__s.__b;
615 return __scalar_hash<long double>::operator()(__v);
620 template <class _Tp, bool = is_enum<_Tp>::value>
621 struct _LIBCPP_TEMPLATE_VIS __enum_hash
622 : public __unary_function<_Tp, size_t>
624 _LIBCPP_HIDE_FROM_ABI
625 size_t operator()(_Tp __v) const _NOEXCEPT
627 typedef typename underlying_type<_Tp>::type type;
628 return hash<type>()(static_cast<type>(__v));
632 struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
633 __enum_hash() = delete;
634 __enum_hash(__enum_hash const&) = delete;
635 __enum_hash& operator=(__enum_hash const&) = delete;
639 struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
643 #if _LIBCPP_STD_VER >= 17
646 struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
647 : public __unary_function<nullptr_t, size_t>
649 _LIBCPP_HIDE_FROM_ABI
650 size_t operator()(nullptr_t) const _NOEXCEPT {
656 #ifndef _LIBCPP_CXX03_LANG
657 template <class _Key, class _Hash>
658 using __check_hash_requirements _LIBCPP_NODEBUG = integral_constant<bool,
659 is_copy_constructible<_Hash>::value &&
660 is_move_constructible<_Hash>::value &&
661 __invokable_r<size_t, _Hash, _Key const&>::value
664 template <class _Key, class _Hash = hash<_Key> >
665 using __has_enabled_hash _LIBCPP_NODEBUG = integral_constant<bool,
666 __check_hash_requirements<_Key, _Hash>::value &&
667 is_default_constructible<_Hash>::value
670 #if _LIBCPP_STD_VER >= 17
671 template <class _Type, class>
672 using __enable_hash_helper_imp _LIBCPP_NODEBUG = _Type;
674 template <class _Type, class ..._Keys>
675 using __enable_hash_helper _LIBCPP_NODEBUG = __enable_hash_helper_imp<_Type,
676 typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
679 template <class _Type, class ...>
680 using __enable_hash_helper _LIBCPP_NODEBUG = _Type;
683 #endif // !_LIBCPP_CXX03_LANG
685 _LIBCPP_END_NAMESPACE_STD
687 #endif // _LIBCPP___FUNCTIONAL_HASH_H