overte/libraries/shared/src/HashKey.h
2017-10-27 07:52:51 -07:00

52 lines
1.5 KiB
C++

//
// HashKey.h
// libraries/shared/src
//
// Created by Andrew Meadows 2017.10.25
// Copyright 2017 High Fidelity, Inc.
//
// Distributed under the Apache License, Version 2.0.
// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//
#ifndef hifi_HashKey_h
#define hifi_HashKey_h
#include <cstddef>
#include <stdint.h>
#include <glm/glm.hpp>
// HashKey for use with btHashMap which requires a particular API for its keys. In particular it
// requires its Key to implement these methods:
//
// bool Key::equals()
// int32_t Key::getHash()
//
// The important thing about the HashKey implementation is that while getHash() returns 32-bits,
// internally HashKey stores a 64-bit hash which is used for the equals() comparison. This allows
// btHashMap to insert "dupe" 32-bit keys to different "values".
class HashKey {
public:
static float getNumQuantizedValuesPerMeter();
// These two methods are required by btHashMap.
bool equals(const HashKey& other) const { return _hash == other._hash; }
int32_t getHash() const { return (int32_t)((uint32_t)_hash); }
void clear() { _hash = _hashCount = 0; }
bool isNull() const { return _hash == 0 && _hashCount == 0; }
void hashUint64(uint64_t data);
void hashFloat(float data);
void hashVec3(const glm::vec3& data);
uint64_t getHash64() const { return _hash; } // for debug/test purposes
private:
uint64_t _hash { 0 };
uint8_t _hashCount { 0 };
};
#endif // hifi_HashKey_h