mirror of
https://github.com/klzgrad/naiveproxy.git
synced 2024-11-28 00:06:09 +03:00
70 lines
2.3 KiB
C
70 lines
2.3 KiB
C
|
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
|
||
|
|
// Use of this source code is governed by a BSD-style license that can be
|
||
|
|
// found in the LICENSE file.
|
||
|
|
|
||
|
|
#ifndef BASE_HASH_H_
|
||
|
|
#define BASE_HASH_H_
|
||
|
|
|
||
|
|
#include <stddef.h>
|
||
|
|
#include <stdint.h>
|
||
|
|
|
||
|
|
#include <limits>
|
||
|
|
#include <string>
|
||
|
|
#include <utility>
|
||
|
|
|
||
|
|
#include "base/base_export.h"
|
||
|
|
#include "base/logging.h"
|
||
|
|
#include "base/strings/string16.h"
|
||
|
|
|
||
|
|
namespace base {
|
||
|
|
|
||
|
|
// Computes a hash of a memory buffer. This hash function is subject to change
|
||
|
|
// in the future, so use only for temporary in-memory structures. If you need
|
||
|
|
// to persist a change on disk or between computers, use PersistentHash().
|
||
|
|
//
|
||
|
|
// WARNING: This hash function should not be used for any cryptographic purpose.
|
||
|
|
BASE_EXPORT uint32_t Hash(const void* data, size_t length);
|
||
|
|
BASE_EXPORT uint32_t Hash(const std::string& str);
|
||
|
|
BASE_EXPORT uint32_t Hash(const string16& str);
|
||
|
|
|
||
|
|
// Computes a hash of a memory buffer. This hash function must not change so
|
||
|
|
// that code can use the hashed values for persistent storage purposes or
|
||
|
|
// sending across the network. If a new persistent hash function is desired, a
|
||
|
|
// new version will have to be added in addition.
|
||
|
|
//
|
||
|
|
// WARNING: This hash function should not be used for any cryptographic purpose.
|
||
|
|
BASE_EXPORT uint32_t PersistentHash(const void* data, size_t length);
|
||
|
|
BASE_EXPORT uint32_t PersistentHash(const std::string& str);
|
||
|
|
|
||
|
|
// Hash pairs of 32-bit or 64-bit numbers.
|
||
|
|
BASE_EXPORT size_t HashInts32(uint32_t value1, uint32_t value2);
|
||
|
|
BASE_EXPORT size_t HashInts64(uint64_t value1, uint64_t value2);
|
||
|
|
|
||
|
|
template <typename T1, typename T2>
|
||
|
|
inline size_t HashInts(T1 value1, T2 value2) {
|
||
|
|
// This condition is expected to be compile-time evaluated and optimised away
|
||
|
|
// in release builds.
|
||
|
|
if (sizeof(T1) > sizeof(uint32_t) || (sizeof(T2) > sizeof(uint32_t)))
|
||
|
|
return HashInts64(value1, value2);
|
||
|
|
|
||
|
|
return HashInts32(value1, value2);
|
||
|
|
}
|
||
|
|
|
||
|
|
// A templated hasher for pairs of integer types. Example:
|
||
|
|
//
|
||
|
|
// using MyPair = std::pair<int32_t, int32_t>;
|
||
|
|
// std::unordered_set<MyPair, base::IntPairHash<MyPair>> set;
|
||
|
|
template <typename T>
|
||
|
|
struct IntPairHash;
|
||
|
|
|
||
|
|
template <typename Type1, typename Type2>
|
||
|
|
struct IntPairHash<std::pair<Type1, Type2>> {
|
||
|
|
size_t operator()(std::pair<Type1, Type2> value) const {
|
||
|
|
return HashInts(value.first, value.second);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace base
|
||
|
|
|
||
|
|
#endif // BASE_HASH_H_
|