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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/* Utilities for hashing pairs. */
#ifndef mozilla_PairHash_h
#define mozilla_PairHash_h
#include "mozilla/CompactPair.h"
#include "mozilla/HashFunctions.h"
#include <utility> // std::pair
namespace mozilla {
/**
* The HashPair overloads below do just what you'd expect.
*
* These functions support hash of std::pair<T,U> and mozilla::CompactPair<T,u>
* where type T and U both support AddToHash.
*/
template <typename U, typename V>
[[nodiscard]] inline HashNumber HashPair(const std::pair<U, V>& pair) {
// Pair hash combines the hash of each member
return HashGeneric(pair.first, pair.second);
}
template <typename U, typename V>
[[nodiscard]] inline HashNumber HashCompactPair(const CompactPair<U, V>& pair) {
// Pair hash combines the hash of each member
return HashGeneric(pair.first(), pair.second());
}
/**
* Hash policy for std::pair compatible with HashTable
*/
template <typename T, typename U>
struct PairHasher {
using Key = std::pair<T, U>;
using Lookup = Key;
static HashNumber hash(const Lookup& aLookup) { return HashPair(aLookup); }
static bool match(const Key& aKey, const Lookup& aLookup) {
return aKey == aLookup;
}
static void rekey(Key& aKey, const Key& aNewKey) { aKey = aNewKey; }
};
/**
* Hash policy for mozilla::CompactPair compatible with HashTable
*/
template <typename T, typename U>
struct CompactPairHasher {
using Key = CompactPair<T, U>;
using Lookup = Key;
static HashNumber hash(const Lookup& aLookup) {
return HashCompactPair(aLookup);
}
static bool match(const Key& aKey, const Lookup& aLookup) {
return aKey == aLookup;
}
static void rekey(Key& aKey, const Key& aNewKey) { aKey = aNewKey; }
};
} // namespace mozilla
#endif /* mozilla_PairHash_h */