michael@0: // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: //
michael@0: 
michael@0: //
michael@0: // Deal with the differences between Microsoft and GNU implemenations
michael@0: // of hash_map. Allows all platforms to use |base::hash_map| and
michael@0: // |base::hash_set|.
michael@0: //  eg:
michael@0: //   base::hash_map<int> my_map;
michael@0: //   base::hash_set<int> my_set;
michael@0: //
michael@0: 
michael@0: #ifndef BASE_HASH_TABLES_H_
michael@0: #define BASE_HASH_TABLES_H_
michael@0: 
michael@0: #include "build/build_config.h"
michael@0: 
michael@0: #include "base/string16.h"
michael@0: 
michael@0: #if defined(COMPILER_MSVC) || (defined(ANDROID) && defined(_STLP_STD_NAME))
michael@0: #include <hash_map>
michael@0: #include <hash_set>
michael@0: namespace base {
michael@0: #ifdef ANDROID
michael@0: using _STLP_STD_NAME::hash_map;
michael@0: using _STLP_STD_NAME::hash_set;
michael@0: #else
michael@0: using stdext::hash_map;
michael@0: using stdext::hash_set;
michael@0: #endif
michael@0: }
michael@0: #elif defined(COMPILER_GCC)
michael@0: // This is a hack to disable the gcc 4.4 warning about hash_map and hash_set
michael@0: // being deprecated.  We can get rid of this when we upgrade to VS2008 and we
michael@0: // can use <tr1/unordered_map> and <tr1/unordered_set>.
michael@0: #ifdef __DEPRECATED
michael@0: #define CHROME_OLD__DEPRECATED __DEPRECATED
michael@0: #undef __DEPRECATED
michael@0: #endif
michael@0: 
michael@0: #include <ext/hash_map>
michael@0: #include <ext/hash_set>
michael@0: #include <string>
michael@0: 
michael@0: #ifdef CHROME_OLD__DEPRECATED
michael@0: #define __DEPRECATED CHROME_OLD__DEPRECATED
michael@0: #undef CHROME_OLD__DEPRECATED
michael@0: #endif
michael@0: 
michael@0: namespace base {
michael@0: using __gnu_cxx::hash_map;
michael@0: using __gnu_cxx::hash_set;
michael@0: }  // namespace base
michael@0: 
michael@0: namespace __gnu_cxx {
michael@0: 
michael@0: // The GNU C++ library provides identiy hash functions for many integral types,
michael@0: // but not for |long long|.  This hash function will truncate if |size_t| is
michael@0: // narrower than |long long|.  This is probably good enough for what we will
michael@0: // use it for.
michael@0: 
michael@0: #define DEFINE_TRIVIAL_HASH(integral_type) \
michael@0:     template<> \
michael@0:     struct hash<integral_type> { \
michael@0:       std::size_t operator()(integral_type value) const { \
michael@0:         return static_cast<std::size_t>(value); \
michael@0:       } \
michael@0:     }
michael@0: 
michael@0: DEFINE_TRIVIAL_HASH(long long);
michael@0: DEFINE_TRIVIAL_HASH(unsigned long long);
michael@0: 
michael@0: #undef DEFINE_TRIVIAL_HASH
michael@0: 
michael@0: // Implement string hash functions so that strings of various flavors can
michael@0: // be used as keys in STL maps and sets.  The hash algorithm comes from the
michael@0: // GNU C++ library, in <tr1/functional>.  It is duplicated here because GCC
michael@0: // versions prior to 4.3.2 are unable to compile <tr1/functional> when RTTI
michael@0: // is disabled, as it is in our build.
michael@0: 
michael@0: #define DEFINE_STRING_HASH(string_type) \
michael@0:     template<> \
michael@0:     struct hash<string_type> { \
michael@0:       std::size_t operator()(const string_type& s) const { \
michael@0:         std::size_t result = 0; \
michael@0:         for (string_type::const_iterator i = s.begin(); i != s.end(); ++i) \
michael@0:           result = (result * 131) + *i; \
michael@0:         return result; \
michael@0:       } \
michael@0:     }
michael@0: 
michael@0: DEFINE_STRING_HASH(std::string);
michael@0: DEFINE_STRING_HASH(std::wstring);
michael@0: 
michael@0: #if defined(WCHAR_T_IS_UTF32)
michael@0: // If string16 and std::wstring are not the same type, provide a
michael@0: // specialization for string16.
michael@0: DEFINE_STRING_HASH(string16);
michael@0: #endif  // WCHAR_T_IS_UTF32
michael@0: 
michael@0: #undef DEFINE_STRING_HASH
michael@0: 
michael@0: }  // namespace __gnu_cxx
michael@0: 
michael@0: #endif  // COMPILER
michael@0: 
michael@0: #endif  // BASE_HASH_TABLES_H_