golden hour

/usr/include/c++/4.8.2/bits

File/Folder	Size	Actions
algorithmfwd.h	20.66 KB
alloc_traits.h	17.66 KB
allocator.h	6.1 KB
atomic_base.h	24.99 KB
atomic_lockfree_defines.h	2.2 KB
basic_ios.h	14.76 KB
basic_ios.tcc	5.89 KB
basic_string.h	109.49 KB
basic_string.tcc	38.43 KB
boost_concept_check.h	26.41 KB
c++0x_warning.h	1.47 KB
char_traits.h	16.95 KB
codecvt.h	16.23 KB
concept_check.h	3.26 KB
cpp_type_traits.h	9.56 KB
cxxabi_forced.h	1.77 KB
deque.tcc	31.91 KB
exception_defines.h	1.6 KB
exception_ptr.h	5.29 KB
forward_list.h	46.72 KB
forward_list.tcc	15.17 KB
fstream.tcc	28.3 KB
functexcept.h	3.04 KB
functional_hash.h	6.05 KB
gslice.h	5.39 KB
gslice_array.h	7.59 KB
hash_bytes.h	2.1 KB
hashtable.h	61.05 KB
hashtable_policy.h	52.72 KB
indirect_array.h	7.68 KB
ios_base.h	27.85 KB
istream.tcc	30.36 KB
list.tcc	12.2 KB
locale_classes.h	22.45 KB
locale_classes.tcc	8.18 KB
locale_facets.h	88.84 KB
locale_facets.tcc	38.02 KB
locale_facets_nonio.h	63.51 KB
locale_facets_nonio.tcc	40.85 KB
localefwd.h	5.1 KB
mask_array.h	7.41 KB
memoryfwd.h	2.36 KB
move.h	5.67 KB
nested_exception.h	4.58 KB
ostream.tcc	12.03 KB
ostream_insert.h	3.91 KB
postypes.h	8.02 KB
ptr_traits.h	5.17 KB
random.h	173.19 KB
random.tcc	106.59 KB
range_access.h	3.06 KB
regex.h	83.49 KB
regex_compiler.h	27.68 KB
regex_constants.h	10.81 KB
regex_cursor.h	2.7 KB
regex_error.h	4.5 KB
regex_grep_matcher.h	4.23 KB
regex_grep_matcher.tcc	5.41 KB
regex_nfa.h	10.65 KB
regex_nfa.tcc	4.85 KB
shared_ptr.h	18.97 KB
shared_ptr_base.h	40.65 KB
slice_array.h	9.12 KB
sstream.tcc	9.27 KB
stl_algo.h	212.55 KB
stl_algobase.h	41.41 KB
stl_bvector.h	28.98 KB
stl_construct.h	5.05 KB
stl_deque.h	66.41 KB
stl_function.h	22.06 KB
stl_heap.h	19.99 KB
stl_iterator.h	35.77 KB
stl_iterator_base_funcs.h	6.8 KB
stl_iterator_base_types.h	8.19 KB
stl_list.h	52.83 KB
stl_map.h	36.78 KB
stl_multimap.h	33.94 KB
stl_multiset.h	28.37 KB
stl_numeric.h	13.5 KB
stl_pair.h	9.63 KB
stl_queue.h	18.21 KB
stl_raw_storage_iter.h	3.37 KB
stl_relops.h	4.49 KB
stl_set.h	28.61 KB
stl_stack.h	9.65 KB
stl_tempbuf.h	8.15 KB
stl_tree.h	53.56 KB
stl_uninitialized.h	19.95 KB
stl_vector.h	48.64 KB
stream_iterator.h	6.44 KB
streambuf.tcc	4.81 KB
streambuf_iterator.h	12.33 KB
stringfwd.h	2.37 KB
unique_ptr.h	17.19 KB
unordered_map.h	47.76 KB
unordered_set.h	43.25 KB
uses_allocator.h	3.49 KB
valarray_after.h	22.12 KB
valarray_array.h	21.23 KB
valarray_array.tcc	7.08 KB
valarray_before.h	18.08 KB
vector.tcc	25.55 KB

Edit: functional_hash.h

// functional_hash.h header -*- C++ -*-

// Copyright (C) 2007-2013 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library 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 General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file bits/functional_hash.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{functional}
 */

#ifndef _FUNCTIONAL_HASH_H
#define _FUNCTIONAL_HASH_H 1

#pragma GCC system_header

#include <bits/hash_bytes.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

/** @defgroup hashes Hashes
   *  @ingroup functors
   *
   *   Hashing functors taking a variable type and returning a @c std::size_t.
   *
   *  @{
   */

template<typename _Result, typename _Arg>
    struct __hash_base
    {
      typedef _Result     result_type;
      typedef _Arg      argument_type;
    };

/// Primary class template hash.
  template<typename _Tp>
    struct hash;

/// Partial specializations for pointer types.
  template<typename _Tp>
    struct hash<_Tp*> : public __hash_base<size_t, _Tp*>
    {
      size_t
      operator()(_Tp* __p) const noexcept
      { return reinterpret_cast<size_t>(__p); }
    };

// Explicit specializations for integer types.
#define _Cxx_hashtable_define_trivial_hash(_Tp) 	\
  template<>						\
    struct hash<_Tp> : public __hash_base<size_t, _Tp>  \
    {                                                   \
      size_t                                            \
      operator()(_Tp __val) const noexcept              \
      { return static_cast<size_t>(__val); }            \
    };

/// Explicit specialization for bool.
  _Cxx_hashtable_define_trivial_hash(bool)

/// Explicit specialization for char.
  _Cxx_hashtable_define_trivial_hash(char)

/// Explicit specialization for signed char.
  _Cxx_hashtable_define_trivial_hash(signed char)

/// Explicit specialization for unsigned char.
  _Cxx_hashtable_define_trivial_hash(unsigned char)

/// Explicit specialization for wchar_t.
  _Cxx_hashtable_define_trivial_hash(wchar_t)

/// Explicit specialization for char16_t.
  _Cxx_hashtable_define_trivial_hash(char16_t)

/// Explicit specialization for char32_t.
  _Cxx_hashtable_define_trivial_hash(char32_t)

/// Explicit specialization for short.
  _Cxx_hashtable_define_trivial_hash(short)

/// Explicit specialization for int.
  _Cxx_hashtable_define_trivial_hash(int)

/// Explicit specialization for long.
  _Cxx_hashtable_define_trivial_hash(long)

/// Explicit specialization for long long.
  _Cxx_hashtable_define_trivial_hash(long long)

/// Explicit specialization for unsigned short.
  _Cxx_hashtable_define_trivial_hash(unsigned short)

/// Explicit specialization for unsigned int.
  _Cxx_hashtable_define_trivial_hash(unsigned int)

/// Explicit specialization for unsigned long.
  _Cxx_hashtable_define_trivial_hash(unsigned long)

/// Explicit specialization for unsigned long long.
  _Cxx_hashtable_define_trivial_hash(unsigned long long)

#undef _Cxx_hashtable_define_trivial_hash

struct _Hash_impl
  {
    static size_t
    hash(const void* __ptr, size_t __clength,
	 size_t __seed = static_cast<size_t>(0xc70f6907UL))
    { return _Hash_bytes(__ptr, __clength, __seed); }

template<typename _Tp>
      static size_t
      hash(const _Tp& __val)
      { return hash(&__val, sizeof(__val)); }

template<typename _Tp>
      static size_t
      __hash_combine(const _Tp& __val, size_t __hash)
      { return hash(&__val, sizeof(__val), __hash); }
  };

struct _Fnv_hash_impl
  {
    static size_t
    hash(const void* __ptr, size_t __clength,
	 size_t __seed = static_cast<size_t>(2166136261UL))
    { return _Fnv_hash_bytes(__ptr, __clength, __seed); }

template<typename _Tp>
      static size_t
      hash(const _Tp& __val)
      { return hash(&__val, sizeof(__val)); }

template<typename _Tp>
      static size_t
      __hash_combine(const _Tp& __val, size_t __hash)
      { return hash(&__val, sizeof(__val), __hash); }
  };

/// Specialization for float.
  template<>
    struct hash<float> : public __hash_base<size_t, float>
    {
      size_t
      operator()(float __val) const noexcept
      {
	// 0 and -0 both hash to zero.
	return __val != 0.0f ? std::_Hash_impl::hash(__val) : 0;
      }
    };

/// Specialization for double.
  template<>
    struct hash<double> : public __hash_base<size_t, double>
    {
      size_t
      operator()(double __val) const noexcept
      {
	// 0 and -0 both hash to zero.
	return __val != 0.0 ? std::_Hash_impl::hash(__val) : 0;
      }
    };

/// Specialization for long double.
  template<>
    struct hash<long double>
    : public __hash_base<size_t, long double>
    {
      _GLIBCXX_PURE size_t
      operator()(long double __val) const noexcept;
    };

// @} group hashes

// Hint about performance of hash functor. If not fast the hash based
  // containers will cache the hash code.
  // Default behavior is to consider that hasher are fast unless specified
  // otherwise.
  template<typename _Hash>
    struct __is_fast_hash : public std::true_type
    { };

template<>
    struct __is_fast_hash<hash<long double>> : public std::false_type
    { };

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif // _FUNCTIONAL_HASH_H