2 // Copyright 2005-2009 Daniel James.
3 // Distributed under the Boost Software License, Version 1.0. (See accompanying
4 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 // Based on Peter Dimov's proposal
7 // http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1756.pdf
10 #if !defined(BOOST_FUNCTIONAL_HASH_HASH_HPP)
11 #define BOOST_FUNCTIONAL_HASH_HASH_HPP
13 #include <boost/functional/hash/hash_fwd.hpp>
15 #include <boost/functional/hash/detail/hash_float.hpp>
17 #include <boost/limits.hpp>
19 #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
20 #include <boost/type_traits/is_pointer.hpp>
23 #if BOOST_WORKAROUND(__GNUC__, < 3) \
24 && !defined(__SGI_STL_PORT) && !defined(_STLPORT_VERSION)
25 #define BOOST_HASH_CHAR_TRAITS string_char_traits
27 #define BOOST_HASH_CHAR_TRAITS char_traits
32 std::size_t hash_value(bool);
33 std::size_t hash_value(char);
34 std::size_t hash_value(unsigned char);
35 std::size_t hash_value(signed char);
36 std::size_t hash_value(short);
37 std::size_t hash_value(unsigned short);
38 std::size_t hash_value(int);
39 std::size_t hash_value(unsigned int);
40 std::size_t hash_value(long);
41 std::size_t hash_value(unsigned long);
43 #if !defined(BOOST_NO_INTRINSIC_WCHAR_T)
44 std::size_t hash_value(wchar_t);
47 #if defined(BOOST_HAS_LONG_LONG)
48 std::size_t hash_value(boost::long_long_type);
49 std::size_t hash_value(boost::ulong_long_type);
52 #if !BOOST_WORKAROUND(__DMC__, <= 0x848)
53 template <class T> std::size_t hash_value(T* const&);
55 template <class T> std::size_t hash_value(T*);
58 #if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
59 template< class T, unsigned N >
60 std::size_t hash_value(const T (&x)[N]);
62 template< class T, unsigned N >
63 std::size_t hash_value(T (&x)[N]);
66 std::size_t hash_value(float v);
67 std::size_t hash_value(double v);
68 std::size_t hash_value(long double v);
70 template <class Ch, class A>
71 std::size_t hash_value(
72 std::basic_string<Ch, std::BOOST_HASH_CHAR_TRAITS<Ch>, A> const&);
79 inline std::size_t hash_value_signed(T val)
81 const int size_t_bits = std::numeric_limits<std::size_t>::digits;
82 // ceiling(std::numeric_limits<T>::digits / size_t_bits) - 1
83 const int length = (std::numeric_limits<T>::digits - 1)
87 T positive = val < 0 ? -1 - val : val;
89 // Hopefully, this loop can be unrolled.
90 for(unsigned int i = length * size_t_bits; i > 0; i -= size_t_bits)
92 seed ^= (std::size_t) (positive >> i) + (seed<<6) + (seed>>2);
94 seed ^= (std::size_t) val + (seed<<6) + (seed>>2);
100 inline std::size_t hash_value_unsigned(T val)
102 const int size_t_bits = std::numeric_limits<std::size_t>::digits;
103 // ceiling(std::numeric_limits<T>::digits / size_t_bits) - 1
104 const int length = (std::numeric_limits<T>::digits - 1)
107 std::size_t seed = 0;
109 // Hopefully, this loop can be unrolled.
110 for(unsigned int i = length * size_t_bits; i > 0; i -= size_t_bits)
112 seed ^= (std::size_t) (val >> i) + (seed<<6) + (seed>>2);
114 seed ^= (std::size_t) val + (seed<<6) + (seed>>2);
120 inline std::size_t hash_value(bool v)
122 return static_cast<std::size_t>(v);
125 inline std::size_t hash_value(char v)
127 return static_cast<std::size_t>(v);
130 inline std::size_t hash_value(unsigned char v)
132 return static_cast<std::size_t>(v);
135 inline std::size_t hash_value(signed char v)
137 return static_cast<std::size_t>(v);
140 inline std::size_t hash_value(short v)
142 return static_cast<std::size_t>(v);
145 inline std::size_t hash_value(unsigned short v)
147 return static_cast<std::size_t>(v);
150 inline std::size_t hash_value(int v)
152 return static_cast<std::size_t>(v);
155 inline std::size_t hash_value(unsigned int v)
157 return static_cast<std::size_t>(v);
160 inline std::size_t hash_value(long v)
162 return static_cast<std::size_t>(v);
165 inline std::size_t hash_value(unsigned long v)
167 return static_cast<std::size_t>(v);
170 #if !defined(BOOST_NO_INTRINSIC_WCHAR_T)
171 inline std::size_t hash_value(wchar_t v)
173 return static_cast<std::size_t>(v);
177 #if defined(BOOST_HAS_LONG_LONG)
178 inline std::size_t hash_value(boost::long_long_type v)
180 return hash_detail::hash_value_signed(v);
183 inline std::size_t hash_value(boost::ulong_long_type v)
185 return hash_detail::hash_value_unsigned(v);
189 // Implementation by Alberto Barbati and Dave Harris.
190 #if !BOOST_WORKAROUND(__DMC__, <= 0x848)
191 template <class T> std::size_t hash_value(T* const& v)
193 template <class T> std::size_t hash_value(T* v)
196 std::size_t x = static_cast<std::size_t>(
197 reinterpret_cast<std::ptrdiff_t>(v));
202 #if defined(BOOST_MSVC)
203 #pragma warning(push)
204 #if BOOST_MSVC <= 1400
205 #pragma warning(disable:4267) // 'argument' : conversion from 'size_t' to
206 // 'unsigned int', possible loss of data
207 // A misguided attempt to detect 64-bit
212 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
214 inline void hash_combine(std::size_t& seed, T& v)
217 inline void hash_combine(std::size_t& seed, T const& v)
220 boost::hash<T> hasher;
221 seed ^= hasher(v) + 0x9e3779b9 + (seed<<6) + (seed>>2);
224 #if defined(BOOST_MSVC)
229 inline std::size_t hash_range(It first, It last)
231 std::size_t seed = 0;
233 for(; first != last; ++first)
235 hash_combine(seed, *first);
242 inline void hash_range(std::size_t& seed, It first, It last)
244 for(; first != last; ++first)
246 hash_combine(seed, *first);
250 #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
252 inline std::size_t hash_range(T* first, T* last)
254 std::size_t seed = 0;
256 for(; first != last; ++first)
258 boost::hash<T> hasher;
259 seed ^= hasher(*first) + 0x9e3779b9 + (seed<<6) + (seed>>2);
266 inline void hash_range(std::size_t& seed, T* first, T* last)
268 for(; first != last; ++first)
270 boost::hash<T> hasher;
271 seed ^= hasher(*first) + 0x9e3779b9 + (seed<<6) + (seed>>2);
276 #if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
277 template< class T, unsigned N >
278 inline std::size_t hash_value(const T (&x)[N])
280 return hash_range(x, x + N);
283 template< class T, unsigned N >
284 inline std::size_t hash_value(T (&x)[N])
286 return hash_range(x, x + N);
290 template <class Ch, class A>
291 inline std::size_t hash_value(
292 std::basic_string<Ch, std::BOOST_HASH_CHAR_TRAITS<Ch>, A> const& v)
294 return hash_range(v.begin(), v.end());
297 inline std::size_t hash_value(float v)
299 return boost::hash_detail::float_hash_value(v);
302 inline std::size_t hash_value(double v)
304 return boost::hash_detail::float_hash_value(v);
307 inline std::size_t hash_value(long double v)
309 return boost::hash_detail::float_hash_value(v);
316 // Define the specializations required by the standard. The general purpose
317 // boost::hash is defined later in extensions.hpp if
318 // BOOST_HASH_NO_EXTENSIONS is not defined.
320 // BOOST_HASH_SPECIALIZE - define a specialization for a type which is
323 // BOOST_HASH_SPECIALIZE_REF - define a specialization for a type which is
326 // These are undefined later.
328 #if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
329 #define BOOST_HASH_SPECIALIZE(type) \
330 template <> struct hash<type> \
331 : public std::unary_function<type, std::size_t> \
333 std::size_t operator()(type v) const \
335 return boost::hash_value(v); \
339 #define BOOST_HASH_SPECIALIZE_REF(type) \
340 template <> struct hash<type> \
341 : public std::unary_function<type, std::size_t> \
343 std::size_t operator()(type const& v) const \
345 return boost::hash_value(v); \
349 #define BOOST_HASH_SPECIALIZE(type) \
350 template <> struct hash<type> \
351 : public std::unary_function<type, std::size_t> \
353 std::size_t operator()(type v) const \
355 return boost::hash_value(v); \
359 template <> struct hash<const type> \
360 : public std::unary_function<const type, std::size_t> \
362 std::size_t operator()(const type v) const \
364 return boost::hash_value(v); \
368 #define BOOST_HASH_SPECIALIZE_REF(type) \
369 template <> struct hash<type> \
370 : public std::unary_function<type, std::size_t> \
372 std::size_t operator()(type const& v) const \
374 return boost::hash_value(v); \
378 template <> struct hash<const type> \
379 : public std::unary_function<const type, std::size_t> \
381 std::size_t operator()(type const& v) const \
383 return boost::hash_value(v); \
388 BOOST_HASH_SPECIALIZE(bool)
389 BOOST_HASH_SPECIALIZE(char)
390 BOOST_HASH_SPECIALIZE(signed char)
391 BOOST_HASH_SPECIALIZE(unsigned char)
392 #if !defined(BOOST_NO_INTRINSIC_WCHAR_T)
393 BOOST_HASH_SPECIALIZE(wchar_t)
395 BOOST_HASH_SPECIALIZE(short)
396 BOOST_HASH_SPECIALIZE(unsigned short)
397 BOOST_HASH_SPECIALIZE(int)
398 BOOST_HASH_SPECIALIZE(unsigned int)
399 BOOST_HASH_SPECIALIZE(long)
400 BOOST_HASH_SPECIALIZE(unsigned long)
402 BOOST_HASH_SPECIALIZE(float)
403 BOOST_HASH_SPECIALIZE(double)
404 BOOST_HASH_SPECIALIZE(long double)
406 BOOST_HASH_SPECIALIZE_REF(std::string)
407 #if !defined(BOOST_NO_STD_WSTRING)
408 BOOST_HASH_SPECIALIZE_REF(std::wstring)
411 #if defined(BOOST_HAS_LONG_LONG)
412 BOOST_HASH_SPECIALIZE(boost::long_long_type)
413 BOOST_HASH_SPECIALIZE(boost::ulong_long_type)
416 #undef BOOST_HASH_SPECIALIZE
417 #undef BOOST_HASH_SPECIALIZE_REF
419 // Specializing boost::hash for pointers.
421 #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
425 : public std::unary_function<T*, std::size_t>
427 std::size_t operator()(T* v) const
429 #if !BOOST_WORKAROUND(__SUNPRO_CC, <= 0x590)
430 return boost::hash_value(v);
432 std::size_t x = static_cast<std::size_t>(
433 reinterpret_cast<std::ptrdiff_t>(v));
442 // For compilers without partial specialization, we define a
443 // boost::hash for all remaining types. But hash_impl is only defined
444 // for pointers in 'extensions.hpp' - so when BOOST_HASH_NO_EXTENSIONS
445 // is defined there will still be a compile error for types not supported
448 namespace hash_detail
450 template <bool IsPointer>
454 struct hash_impl<true>
458 : public std::unary_function<T, std::size_t>
460 std::size_t operator()(T val) const
462 #if !BOOST_WORKAROUND(__SUNPRO_CC, <= 590)
463 return boost::hash_value(val);
465 std::size_t x = static_cast<std::size_t>(
466 reinterpret_cast<std::ptrdiff_t>(val));
475 template <class T> struct hash
476 : public boost::hash_detail::hash_impl<boost::is_pointer<T>::value>
477 ::BOOST_NESTED_TEMPLATE inner<T>
484 #undef BOOST_HASH_CHAR_TRAITS
486 #endif // BOOST_FUNCTIONAL_HASH_HASH_HPP
488 // Include this outside of the include guards in case the file is included
489 // twice - once with BOOST_HASH_NO_EXTENSIONS defined, and then with it
492 #if !defined(BOOST_HASH_NO_EXTENSIONS) \
493 && !defined(BOOST_FUNCTIONAL_HASH_EXTENSIONS_HPP)
494 #include <boost/functional/hash/extensions.hpp>