include/tr1/functional_hash.h

39 #include <cmath>  // for std::frexp
41 namespace std
45   // Definition of default hash function std::tr1::hash<>.  The types for
46   // which std::tr1::hash<T> is defined is in clause 6.3.3. of the PDTR.
53     : public std::unary_function<_Tp, std::size_t>      \
55       std::size_t                                       \
57       { return static_cast<std::size_t>(__val); }       \
78     : public std::unary_function<_Tp*, std::size_t>
80       std::size_t
82       { return reinterpret_cast<std::size_t>(__p); }
86   // (used by the next specializations of std::tr1::hash<>)
89   template<std::size_t = sizeof(std::size_t)>
92       static std::size_t
93       hash(const char* __first, std::size_t __length)
95 	std::size_t __result = 0;
105       static std::size_t
106       hash(const char* __first, std::size_t __length)
108 	std::size_t __result = static_cast<std::size_t>(2166136261UL);
111 	    __result ^= static_cast<std::size_t>(*__first++);
112 	    __result *= static_cast<std::size_t>(16777619UL);
121       static std::size_t
122       hash(const char* __first, std::size_t __length)
124 	std::size_t __result =
125 	  static_cast<std::size_t>(14695981039346656037ULL);
128 	    __result ^= static_cast<std::size_t>(*__first++);
129 	    __result *= static_cast<std::size_t>(1099511628211ULL);
139     struct hash<std::string>
140     : public std::unary_function<std::string, std::size_t>
142       std::size_t
143       operator()(const std::string& __s) const
149     struct hash<std::wstring>
150     : public std::unary_function<std::wstring, std::size_t>
152       std::size_t
153       operator()(const std::wstring& __s) const
163     : public std::unary_function<float, std::size_t>
165       std::size_t
168 	std::size_t __result = 0;
180     : public std::unary_function<double, std::size_t>
182       std::size_t
185 	std::size_t __result = 0;
199     : public std::unary_function<long double, std::size_t>
201       std::size_t
204 	std::size_t __result = 0;
207 	__ldval = std::frexp(__ldval, &__exponent);
211 	  std::numeric_limits<std::size_t>::max() + 1.0l;
216 	const std::size_t __hibits = (std::size_t)__ldval;
219 	const std::size_t __coeff =
220 	  (std::numeric_limits<std::size_t>::max()
221 	   / std::numeric_limits<long double>::max_exponent);
223 	__result = __hibits + (std::size_t)__ldval + __coeff * __exponent;