libcxx/include/__functional/hash.h

   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-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___FUNCTIONAL_HASH_H
  10 #define _LIBCPP___FUNCTIONAL_HASH_H
  11
  12 #include <__config>
  13 #include <__functional/unary_function.h>
  14 #include <__tuple>
  15 #include <__utility/forward.h>
  16 #include <__utility/move.h>
  17 #include <__utility/pair.h>
  18 #include <__utility/swap.h>
  19 #include <cstddef>
  20 #include <cstdint>
  21 #include <cstring>
  22 #include <limits>
  23 #include <type_traits>
  24
  25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  26 #pragma GCC system_header
  27 #endif
  28
  29 _LIBCPP_BEGIN_NAMESPACE_STD
  30
  31 template <class _Size>
  32 inline _LIBCPP_INLINE_VISIBILITY
  33 _Size
  34 __loadword(const void* __p)
  35 {
  36     _Size __r;
  37     _VSTD::memcpy(&__r, __p, sizeof(__r));
  38     return __r;
  39 }
  40
  41 // We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
  42 // is 64 bits.  This is because cityhash64 uses 64bit x 64bit
  43 // multiplication, which can be very slow on 32-bit systems.
  44 template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
  45 struct __murmur2_or_cityhash;
  46
  47 template <class _Size>
  48 struct __murmur2_or_cityhash<_Size, 32>
  49 {
  50     inline _Size operator()(const void* __key, _Size __len)
  51          _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
  52 };
  53
  54 // murmur2
  55 template <class _Size>
  56 _Size
  57 __murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
  58 {
  59     const _Size __m = 0x5bd1e995;
  60     const _Size __r = 24;
  61     _Size __h = __len;
  62     const unsigned char* __data = static_cast<const unsigned char*>(__key);
  63     for (; __len >= 4; __data += 4, __len -= 4)
  64     {
  65         _Size __k = __loadword<_Size>(__data);
  66         __k *= __m;
  67         __k ^= __k >> __r;
  68         __k *= __m;
  69         __h *= __m;
  70         __h ^= __k;
  71     }
  72     switch (__len)
  73     {
  74     case 3:
  75         __h ^= static_cast<_Size>(__data[2] << 16);
  76         _LIBCPP_FALLTHROUGH();
  77     case 2:
  78         __h ^= static_cast<_Size>(__data[1] << 8);
  79         _LIBCPP_FALLTHROUGH();
  80     case 1:
  81         __h ^= __data[0];
  82         __h *= __m;
  83     }
  84     __h ^= __h >> 13;
  85     __h *= __m;
  86     __h ^= __h >> 15;
  87     return __h;
  88 }
  89
  90 template <class _Size>
  91 struct __murmur2_or_cityhash<_Size, 64>
  92 {
  93     inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
  94
  95  private:
  96   // Some primes between 2^63 and 2^64.
  97   static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
  98   static const _Size __k1 = 0xb492b66fbe98f273ULL;
  99   static const _Size __k2 = 0x9ae16a3b2f90404fULL;
 100   static const _Size __k3 = 0xc949d7c7509e6557ULL;
 101
 102   static _Size __rotate(_Size __val, int __shift) {
 103     return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
 104   }
 105
 106   static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
 107     return (__val >> __shift) | (__val << (64 - __shift));
 108   }
 109
 110   static _Size __shift_mix(_Size __val) {
 111     return __val ^ (__val >> 47);
 112   }
 113
 114   static _Size __hash_len_16(_Size __u, _Size __v)
 115      _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
 116   {
 117     const _Size __mul = 0x9ddfea08eb382d69ULL;
 118     _Size __a = (__u ^ __v) * __mul;
 119     __a ^= (__a >> 47);
 120     _Size __b = (__v ^ __a) * __mul;
 121     __b ^= (__b >> 47);
 122     __b *= __mul;
 123     return __b;
 124   }
 125
 126   static _Size __hash_len_0_to_16(const char* __s, _Size __len)
 127      _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
 128   {
 129     if (__len > 8) {
 130       const _Size __a = __loadword<_Size>(__s);
 131       const _Size __b = __loadword<_Size>(__s + __len - 8);
 132       return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
 133     }
 134     if (__len >= 4) {
 135       const uint32_t __a = __loadword<uint32_t>(__s);
 136       const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
 137       return __hash_len_16(__len + (__a << 3), __b);
 138     }
 139     if (__len > 0) {
 140       const unsigned char __a = static_cast<unsigned char>(__s[0]);
 141       const unsigned char __b = static_cast<unsigned char>(__s[__len >> 1]);
 142       const unsigned char __c = static_cast<unsigned char>(__s[__len - 1]);
 143       const uint32_t __y = static_cast<uint32_t>(__a) +
 144                            (static_cast<uint32_t>(__b) << 8);
 145       const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
 146       return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
 147     }
 148     return __k2;
 149   }
 150
 151   static _Size __hash_len_17_to_32(const char *__s, _Size __len)
 152      _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
 153   {
 154     const _Size __a = __loadword<_Size>(__s) * __k1;
 155     const _Size __b = __loadword<_Size>(__s + 8);
 156     const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
 157     const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
 158     return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
 159                          __a + __rotate(__b ^ __k3, 20) - __c + __len);
 160   }
 161
 162   // Return a 16-byte hash for 48 bytes.  Quick and dirty.
 163   // Callers do best to use "random-looking" values for a and b.
 164   static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
 165       _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
 166         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
 167   {
 168     __a += __w;
 169     __b = __rotate(__b + __a + __z, 21);
 170     const _Size __c = __a;
 171     __a += __x;
 172     __a += __y;
 173     __b += __rotate(__a, 44);
 174     return pair<_Size, _Size>(__a + __z, __b + __c);
 175   }
 176
 177   // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
 178   static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
 179       const char* __s, _Size __a, _Size __b)
 180     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
 181   {
 182     return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
 183                                          __loadword<_Size>(__s + 8),
 184                                          __loadword<_Size>(__s + 16),
 185                                          __loadword<_Size>(__s + 24),
 186                                          __a,
 187                                          __b);
 188   }
 189
 190   // Return an 8-byte hash for 33 to 64 bytes.
 191   static _Size __hash_len_33_to_64(const char *__s, size_t __len)
 192     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
 193   {
 194     _Size __z = __loadword<_Size>(__s + 24);
 195     _Size __a = __loadword<_Size>(__s) +
 196                 (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
 197     _Size __b = __rotate(__a + __z, 52);
 198     _Size __c = __rotate(__a, 37);
 199     __a += __loadword<_Size>(__s + 8);
 200     __c += __rotate(__a, 7);
 201     __a += __loadword<_Size>(__s + 16);
 202     _Size __vf = __a + __z;
 203     _Size __vs = __b + __rotate(__a, 31) + __c;
 204     __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
 205     __z += __loadword<_Size>(__s + __len - 8);
 206     __b = __rotate(__a + __z, 52);
 207     __c = __rotate(__a, 37);
 208     __a += __loadword<_Size>(__s + __len - 24);
 209     __c += __rotate(__a, 7);
 210     __a += __loadword<_Size>(__s + __len - 16);
 211     _Size __wf = __a + __z;
 212     _Size __ws = __b + __rotate(__a, 31) + __c;
 213     _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
 214     return __shift_mix(__r * __k0 + __vs) * __k2;
 215   }
 216 };
 217
 218 // cityhash64
 219 template <class _Size>
 220 _Size
 221 __murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
 222 {
 223   const char* __s = static_cast<const char*>(__key);
 224   if (__len <= 32) {
 225     if (__len <= 16) {
 226       return __hash_len_0_to_16(__s, __len);
 227     } else {
 228       return __hash_len_17_to_32(__s, __len);
 229     }
 230   } else if (__len <= 64) {
 231     return __hash_len_33_to_64(__s, __len);
 232   }
 233
 234   // For strings over 64 bytes we hash the end first, and then as we
 235   // loop we keep 56 bytes of state: v, w, x, y, and z.
 236   _Size __x = __loadword<_Size>(__s + __len - 40);
 237   _Size __y = __loadword<_Size>(__s + __len - 16) +
 238               __loadword<_Size>(__s + __len - 56);
 239   _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
 240                           __loadword<_Size>(__s + __len - 24));
 241   pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
 242   pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
 243   __x = __x * __k1 + __loadword<_Size>(__s);
 244
 245   // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
 246   __len = (__len - 1) & ~static_cast<_Size>(63);
 247   do {
 248     __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
 249     __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
 250     __x ^= __w.second;
 251     __y += __v.first + __loadword<_Size>(__s + 40);
 252     __z = __rotate(__z + __w.first, 33) * __k1;
 253     __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
 254     __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
 255                                         __y + __loadword<_Size>(__s + 16));
 256     _VSTD::swap(__z, __x);
 257     __s += 64;
 258     __len -= 64;
 259   } while (__len != 0);
 260   return __hash_len_16(
 261       __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
 262       __hash_len_16(__v.second, __w.second) + __x);
 263 }
 264
 265 template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
 266 struct __scalar_hash;
 267
 268 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 269 template <class _Tp>
 270 struct __scalar_hash<_Tp, 0>
 271 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 272     : public unary_function<_Tp, size_t>
 273 #endif
 274 {
 275 _LIBCPP_SUPPRESS_DEPRECATED_POP
 276 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 277     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 278     _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
 279 #endif
 280     _LIBCPP_INLINE_VISIBILITY
 281     size_t operator()(_Tp __v) const _NOEXCEPT
 282     {
 283         union
 284         {
 285             _Tp    __t;
 286             size_t __a;
 287         } __u;
 288         __u.__a = 0;
 289         __u.__t = __v;
 290         return __u.__a;
 291     }
 292 };
 293
 294 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 295 template <class _Tp>
 296 struct __scalar_hash<_Tp, 1>
 297 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 298     : public unary_function<_Tp, size_t>
 299 #endif
 300 {
 301 _LIBCPP_SUPPRESS_DEPRECATED_POP
 302 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 303     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 304     _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
 305 #endif
 306     _LIBCPP_INLINE_VISIBILITY
 307     size_t operator()(_Tp __v) const _NOEXCEPT
 308     {
 309         union
 310         {
 311             _Tp    __t;
 312             size_t __a;
 313         } __u;
 314         __u.__t = __v;
 315         return __u.__a;
 316     }
 317 };
 318
 319 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 320 template <class _Tp>
 321 struct __scalar_hash<_Tp, 2>
 322 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 323     : public unary_function<_Tp, size_t>
 324 #endif
 325 {
 326 _LIBCPP_SUPPRESS_DEPRECATED_POP
 327 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 328     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 329     _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
 330 #endif
 331     _LIBCPP_INLINE_VISIBILITY
 332     size_t operator()(_Tp __v) const _NOEXCEPT
 333     {
 334         union
 335         {
 336             _Tp __t;
 337             struct
 338             {
 339                 size_t __a;
 340                 size_t __b;
 341             } __s;
 342         } __u;
 343         __u.__t = __v;
 344         return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
 345     }
 346 };
 347
 348 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 349 template <class _Tp>
 350 struct __scalar_hash<_Tp, 3>
 351 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 352     : public unary_function<_Tp, size_t>
 353 #endif
 354 {
 355 _LIBCPP_SUPPRESS_DEPRECATED_POP
 356 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 357     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 358     _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
 359 #endif
 360     _LIBCPP_INLINE_VISIBILITY
 361     size_t operator()(_Tp __v) const _NOEXCEPT
 362     {
 363         union
 364         {
 365             _Tp __t;
 366             struct
 367             {
 368                 size_t __a;
 369                 size_t __b;
 370                 size_t __c;
 371             } __s;
 372         } __u;
 373         __u.__t = __v;
 374         return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
 375     }
 376 };
 377
 378 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 379 template <class _Tp>
 380 struct __scalar_hash<_Tp, 4>
 381 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 382     : public unary_function<_Tp, size_t>
 383 #endif
 384 {
 385 _LIBCPP_SUPPRESS_DEPRECATED_POP
 386 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 387     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 388     _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
 389 #endif
 390     _LIBCPP_INLINE_VISIBILITY
 391     size_t operator()(_Tp __v) const _NOEXCEPT
 392     {
 393         union
 394         {
 395             _Tp __t;
 396             struct
 397             {
 398                 size_t __a;
 399                 size_t __b;
 400                 size_t __c;
 401                 size_t __d;
 402             } __s;
 403         } __u;
 404         __u.__t = __v;
 405         return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
 406     }
 407 };
 408
 409 struct _PairT {
 410   size_t first;
 411   size_t second;
 412 };
 413
 414 _LIBCPP_INLINE_VISIBILITY
 415 inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
 416     typedef __scalar_hash<_PairT> _HashT;
 417     const _PairT __p = {__lhs, __rhs};
 418     return _HashT()(__p);
 419 }
 420
 421 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 422 template<class _Tp>
 423 struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
 424 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 425     : public unary_function<_Tp*, size_t>
 426 #endif
 427 {
 428 _LIBCPP_SUPPRESS_DEPRECATED_POP
 429 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 430     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 431     _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp* argument_type;
 432 #endif
 433     _LIBCPP_INLINE_VISIBILITY
 434     size_t operator()(_Tp* __v) const _NOEXCEPT
 435     {
 436         union
 437         {
 438             _Tp* __t;
 439             size_t __a;
 440         } __u;
 441         __u.__t = __v;
 442         return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
 443     }
 444 };
 445
 446 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 447 template <>
 448 struct _LIBCPP_TEMPLATE_VIS hash<bool>
 449 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 450     : public unary_function<bool, size_t>
 451 #endif
 452 {
 453 _LIBCPP_SUPPRESS_DEPRECATED_POP
 454 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 455     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 456     _LIBCPP_DEPRECATED_IN_CXX17 typedef bool argument_type;
 457 #endif
 458     _LIBCPP_INLINE_VISIBILITY
 459     size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 460 };
 461
 462 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 463 template <>
 464 struct _LIBCPP_TEMPLATE_VIS hash<char>
 465 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 466     : public unary_function<char, size_t>
 467 #endif
 468 {
 469 _LIBCPP_SUPPRESS_DEPRECATED_POP
 470 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 471     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 472     _LIBCPP_DEPRECATED_IN_CXX17 typedef char argument_type;
 473 #endif
 474     _LIBCPP_INLINE_VISIBILITY
 475     size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 476 };
 477
 478 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 479 template <>
 480 struct _LIBCPP_TEMPLATE_VIS hash<signed char>
 481 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 482     : public unary_function<signed char, size_t>
 483 #endif
 484 {
 485 _LIBCPP_SUPPRESS_DEPRECATED_POP
 486 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 487     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 488     _LIBCPP_DEPRECATED_IN_CXX17 typedef signed char argument_type;
 489 #endif
 490     _LIBCPP_INLINE_VISIBILITY
 491     size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 492 };
 493
 494 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 495 template <>
 496 struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
 497 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 498     : public unary_function<unsigned char, size_t>
 499 #endif
 500 {
 501 _LIBCPP_SUPPRESS_DEPRECATED_POP
 502 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 503     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 504     _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned char argument_type;
 505 #endif
 506     _LIBCPP_INLINE_VISIBILITY
 507     size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 508 };
 509
 510 #ifndef _LIBCPP_HAS_NO_CHAR8_T
 511 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 512 template <>
 513 struct _LIBCPP_TEMPLATE_VIS hash<char8_t>
 514 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 515     : public unary_function<char8_t, size_t>
 516 #endif
 517 {
 518 _LIBCPP_SUPPRESS_DEPRECATED_POP
 519 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 520     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 521     _LIBCPP_DEPRECATED_IN_CXX17 typedef char8_t argument_type;
 522 #endif
 523     _LIBCPP_INLINE_VISIBILITY
 524     size_t operator()(char8_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 525 };
 526 #endif // !_LIBCPP_HAS_NO_CHAR8_T
 527
 528 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 529
 530 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 531 template <>
 532 struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
 533 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 534     : public unary_function<char16_t, size_t>
 535 #endif
 536 {
 537 _LIBCPP_SUPPRESS_DEPRECATED_POP
 538 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 539     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 540     _LIBCPP_DEPRECATED_IN_CXX17 typedef char16_t argument_type;
 541 #endif
 542     _LIBCPP_INLINE_VISIBILITY
 543     size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 544 };
 545
 546 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 547 template <>
 548 struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
 549 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 550     : public unary_function<char32_t, size_t>
 551 #endif
 552 {
 553 _LIBCPP_SUPPRESS_DEPRECATED_POP
 554 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 555     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 556     _LIBCPP_DEPRECATED_IN_CXX17 typedef char32_t argument_type;
 557 #endif
 558     _LIBCPP_INLINE_VISIBILITY
 559     size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 560 };
 561
 562 #endif // _LIBCPP_HAS_NO_UNICODE_CHARS
 563
 564 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 565 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 566 template <>
 567 struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
 568 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 569     : public unary_function<wchar_t, size_t>
 570 #endif
 571 {
 572 _LIBCPP_SUPPRESS_DEPRECATED_POP
 573 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 574     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 575     _LIBCPP_DEPRECATED_IN_CXX17 typedef wchar_t argument_type;
 576 #endif
 577     _LIBCPP_INLINE_VISIBILITY
 578     size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 579 };
 580 #endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
 581
 582 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 583 template <>
 584 struct _LIBCPP_TEMPLATE_VIS hash<short>
 585 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 586     : public unary_function<short, size_t>
 587 #endif
 588 {
 589 _LIBCPP_SUPPRESS_DEPRECATED_POP
 590 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 591     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 592     _LIBCPP_DEPRECATED_IN_CXX17 typedef short argument_type;
 593 #endif
 594     _LIBCPP_INLINE_VISIBILITY
 595     size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 596 };
 597
 598 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 599 template <>
 600 struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
 601 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 602     : public unary_function<unsigned short, size_t>
 603 #endif
 604 {
 605 _LIBCPP_SUPPRESS_DEPRECATED_POP
 606 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 607     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 608     _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned short argument_type;
 609 #endif
 610     _LIBCPP_INLINE_VISIBILITY
 611     size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 612 };
 613
 614 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 615 template <>
 616 struct _LIBCPP_TEMPLATE_VIS hash<int>
 617 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 618     : public unary_function<int, size_t>
 619 #endif
 620 {
 621 _LIBCPP_SUPPRESS_DEPRECATED_POP
 622 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 623     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 624     _LIBCPP_DEPRECATED_IN_CXX17 typedef int argument_type;
 625 #endif
 626     _LIBCPP_INLINE_VISIBILITY
 627     size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 628 };
 629
 630 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 631 template <>
 632 struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
 633 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 634     : public unary_function<unsigned int, size_t>
 635 #endif
 636 {
 637 _LIBCPP_SUPPRESS_DEPRECATED_POP
 638 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 639     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 640     _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned int argument_type;
 641 #endif
 642     _LIBCPP_INLINE_VISIBILITY
 643     size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 644 };
 645
 646 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 647 template <>
 648 struct _LIBCPP_TEMPLATE_VIS hash<long>
 649 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 650     : public unary_function<long, size_t>
 651 #endif
 652 {
 653 _LIBCPP_SUPPRESS_DEPRECATED_POP
 654 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 655     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 656     _LIBCPP_DEPRECATED_IN_CXX17 typedef long argument_type;
 657 #endif
 658     _LIBCPP_INLINE_VISIBILITY
 659     size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 660 };
 661
 662 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 663 template <>
 664 struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
 665 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 666     : public unary_function<unsigned long, size_t>
 667 #endif
 668 {
 669 _LIBCPP_SUPPRESS_DEPRECATED_POP
 670 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 671     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 672     _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned long argument_type;
 673 #endif
 674     _LIBCPP_INLINE_VISIBILITY
 675     size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
 676 };
 677
 678 template <>
 679 struct _LIBCPP_TEMPLATE_VIS hash<long long>
 680     : public __scalar_hash<long long>
 681 {
 682 };
 683
 684 template <>
 685 struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
 686     : public __scalar_hash<unsigned long long>
 687 {
 688 };
 689
 690 #ifndef _LIBCPP_HAS_NO_INT128
 691
 692 template <>
 693 struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
 694     : public __scalar_hash<__int128_t>
 695 {
 696 };
 697
 698 template <>
 699 struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
 700     : public __scalar_hash<__uint128_t>
 701 {
 702 };
 703
 704 #endif
 705
 706 template <>
 707 struct _LIBCPP_TEMPLATE_VIS hash<float>
 708     : public __scalar_hash<float>
 709 {
 710     _LIBCPP_INLINE_VISIBILITY
 711     size_t operator()(float __v) const _NOEXCEPT
 712     {
 713         // -0.0 and 0.0 should return same hash
 714        if (__v == 0.0f)
 715            return 0;
 716         return __scalar_hash<float>::operator()(__v);
 717     }
 718 };
 719
 720 template <>
 721 struct _LIBCPP_TEMPLATE_VIS hash<double>
 722     : public __scalar_hash<double>
 723 {
 724     _LIBCPP_INLINE_VISIBILITY
 725     size_t operator()(double __v) const _NOEXCEPT
 726     {
 727         // -0.0 and 0.0 should return same hash
 728        if (__v == 0.0)
 729            return 0;
 730         return __scalar_hash<double>::operator()(__v);
 731     }
 732 };
 733
 734 template <>
 735 struct _LIBCPP_TEMPLATE_VIS hash<long double>
 736     : public __scalar_hash<long double>
 737 {
 738     _LIBCPP_INLINE_VISIBILITY
 739     size_t operator()(long double __v) const _NOEXCEPT
 740     {
 741         // -0.0 and 0.0 should return same hash
 742         if (__v == 0.0L)
 743             return 0;
 744 #if defined(__i386__) || (defined(__x86_64__) && defined(__ILP32__))
 745         // Zero out padding bits
 746         union
 747         {
 748             long double __t;
 749             struct
 750             {
 751                 size_t __a;
 752                 size_t __b;
 753                 size_t __c;
 754                 size_t __d;
 755             } __s;
 756         } __u;
 757         __u.__s.__a = 0;
 758         __u.__s.__b = 0;
 759         __u.__s.__c = 0;
 760         __u.__s.__d = 0;
 761         __u.__t = __v;
 762         return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
 763 #elif defined(__x86_64__)
 764         // Zero out padding bits
 765         union
 766         {
 767             long double __t;
 768             struct
 769             {
 770                 size_t __a;
 771                 size_t __b;
 772             } __s;
 773         } __u;
 774         __u.__s.__a = 0;
 775         __u.__s.__b = 0;
 776         __u.__t = __v;
 777         return __u.__s.__a ^ __u.__s.__b;
 778 #else
 779         return __scalar_hash<long double>::operator()(__v);
 780 #endif
 781     }
 782 };
 783
 784 #if _LIBCPP_STD_VER > 11
 785
 786 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 787 template <class _Tp, bool = is_enum<_Tp>::value>
 788 struct _LIBCPP_TEMPLATE_VIS __enum_hash
 789 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 790     : public unary_function<_Tp, size_t>
 791 #endif
 792 {
 793 _LIBCPP_SUPPRESS_DEPRECATED_POP
 794 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 795     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 796     _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
 797 #endif
 798     _LIBCPP_INLINE_VISIBILITY
 799     size_t operator()(_Tp __v) const _NOEXCEPT
 800     {
 801         typedef typename underlying_type<_Tp>::type type;
 802         return hash<type>{}(static_cast<type>(__v));
 803     }
 804 };
 805 template <class _Tp>
 806 struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
 807     __enum_hash() = delete;
 808     __enum_hash(__enum_hash const&) = delete;
 809     __enum_hash& operator=(__enum_hash const&) = delete;
 810 };
 811
 812 template <class _Tp>
 813 struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
 814 {
 815 };
 816 #endif
 817
 818 #if _LIBCPP_STD_VER > 14
 819
 820 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 821 template <>
 822 struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
 823 #if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
 824   : public unary_function<nullptr_t, size_t>
 825 #endif
 826 {
 827 _LIBCPP_SUPPRESS_DEPRECATED_POP
 828 #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
 829     _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
 830     _LIBCPP_DEPRECATED_IN_CXX17 typedef nullptr_t argument_type;
 831 #endif
 832     _LIBCPP_INLINE_VISIBILITY
 833     size_t operator()(nullptr_t) const _NOEXCEPT {
 834         return 662607004ull;
 835     }
 836 };
 837 #endif
 838
 839 #ifndef _LIBCPP_CXX03_LANG
 840 template <class _Key, class _Hash>
 841 using __check_hash_requirements _LIBCPP_NODEBUG = integral_constant<bool,
 842     is_copy_constructible<_Hash>::value &&
 843     is_move_constructible<_Hash>::value &&
 844     __invokable_r<size_t, _Hash, _Key const&>::value
 845 >;
 846
 847 template <class _Key, class _Hash = hash<_Key> >
 848 using __has_enabled_hash _LIBCPP_NODEBUG = integral_constant<bool,
 849     __check_hash_requirements<_Key, _Hash>::value &&
 850     is_default_constructible<_Hash>::value
 851 >;
 852
 853 #if _LIBCPP_STD_VER > 14
 854 template <class _Type, class>
 855 using __enable_hash_helper_imp _LIBCPP_NODEBUG = _Type;
 856
 857 template <class _Type, class ..._Keys>
 858 using __enable_hash_helper _LIBCPP_NODEBUG = __enable_hash_helper_imp<_Type,
 859   typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
 860 >;
 861 #else
 862 template <class _Type, class ...>
 863 using __enable_hash_helper _LIBCPP_NODEBUG = _Type;
 864 #endif
 865
 866 #endif // !_LIBCPP_CXX03_LANG
 867
 868 _LIBCPP_END_NAMESPACE_STD
 869
 870 #endif // _LIBCPP___FUNCTIONAL_HASH_H