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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Author: kenton@google.com (Kenton Varda)
#ifndef GOOGLE_PROTOBUF_STUBS_HASH_H__
#define GOOGLE_PROTOBUF_STUBS_HASH_H__
#include <cstring>
#include <string>
#include <unordered_map>
#include <unordered_set>
# define GOOGLE_PROTOBUF_HASH_NAMESPACE_DECLARATION_START \
namespace google { \
namespace protobuf {
# define GOOGLE_PROTOBUF_HASH_NAMESPACE_DECLARATION_END }}
namespace google {
namespace protobuf {
template <typename Key>
struct hash : public std::hash<Key> {};
template <typename Key>
struct hash<const Key*> {
inline size_t operator()(const Key* key) const {
return reinterpret_cast<size_t>(key);
}
};
// Unlike the old SGI version, the TR1 "hash" does not special-case char*. So,
// we go ahead and provide our own implementation.
template <>
struct hash<const char*> {
inline size_t operator()(const char* str) const {
size_t result = 0;
for (; *str != '\0'; str++) {
result = 5 * result + static_cast<size_t>(*str);
}
return result;
}
};
template<>
struct hash<bool> {
size_t operator()(bool x) const {
return static_cast<size_t>(x);
}
};
template <>
struct hash<std::string> {
inline size_t operator()(const std::string& key) const {
return hash<const char*>()(key.c_str());
}
static const size_t bucket_size = 4;
static const size_t min_buckets = 8;
inline bool operator()(const std::string& a, const std::string& b) const {
return a < b;
}
};
template <typename First, typename Second>
struct hash<std::pair<First, Second> > {
inline size_t operator()(const std::pair<First, Second>& key) const {
size_t first_hash = hash<First>()(key.first);
size_t second_hash = hash<Second>()(key.second);
// FIXME(kenton): What is the best way to compute this hash? I have
// no idea! This seems a bit better than an XOR.
return first_hash * ((1 << 16) - 1) + second_hash;
}
static const size_t bucket_size = 4;
static const size_t min_buckets = 8;
inline bool operator()(const std::pair<First, Second>& a,
const std::pair<First, Second>& b) const {
return a < b;
}
};
} // namespace protobuf
} // namespace google
#endif // GOOGLE_PROTOBUF_STUBS_HASH_H__
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