layers/external/parallel_hashmap/phmap_fwd_decl.h

#if !defined(phmap_fwd_decl_h_guard_)
#define phmap_fwd_decl_h_guard_

// ---------------------------------------------------------------------------
// Copyright (c) 2019, Gregory Popovitch - greg7mdp@gmail.com
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
// ---------------------------------------------------------------------------

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable : 4514)  // unreferenced inline function has been removed
#pragma warning(disable : 4710)  // function not inlined
#pragma warning(disable : 4711)  // selected for automatic inline expansion
#endif

#include <memory>
#include <utility>
#include <mutex>

#if defined(PHMAP_USE_ABSL_HASH) && !defined(ABSL_HASH_HASH_H_)
namespace absl {
template <class T>
struct Hash;
};
#endif

namespace phmap {

#if defined(PHMAP_USE_ABSL_HASH)
template <class T>
using Hash = ::absl::Hash<T>;
#else
template <class T>
struct Hash;
#endif

template <class T>
struct EqualTo;
template <class T>
struct Less;
template <class T>
using Allocator = typename std::allocator<T>;
template <class T1, class T2>
using Pair = typename std::pair<T1, T2>;

class NullMutex;

namespace priv {

// The hash of an object of type T is computed by using phmap::Hash.
template <class T, class E = void>
struct HashEq {
    using Hash = phmap::Hash<T>;
    using Eq = phmap::EqualTo<T>;
};

template <class T>
using hash_default_hash = typename priv::HashEq<T>::Hash;

template <class T>
using hash_default_eq = typename priv::HashEq<T>::Eq;

// type alias for std::allocator so we can forward declare without including other headers
template <class T>
using Allocator = typename phmap::Allocator<T>;

// type alias for std::pair so we can forward declare without including other headers
template <class T1, class T2>
using Pair = typename phmap::Pair<T1, T2>;

}  // namespace priv

// ------------- forward declarations for hash containers ----------------------------------
template <class T, class Hash = phmap::priv::hash_default_hash<T>, class Eq = phmap::priv::hash_default_eq<T>,
          class Alloc = phmap::priv::Allocator<T>>  // alias for std::allocator
class flat_hash_set;

template <class K, class V, class Hash = phmap::priv::hash_default_hash<K>, class Eq = phmap::priv::hash_default_eq<K>,
          class Alloc = phmap::priv::Allocator<phmap::priv::Pair<const K, V>>>  // alias for std::allocator
class flat_hash_map;

template <class T, class Hash = phmap::priv::hash_default_hash<T>, class Eq = phmap::priv::hash_default_eq<T>,
          class Alloc = phmap::priv::Allocator<T>>  // alias for std::allocator
class node_hash_set;

template <class Key, class Value, class Hash = phmap::priv::hash_default_hash<Key>, class Eq = phmap::priv::hash_default_eq<Key>,
          class Alloc = phmap::priv::Allocator<phmap::priv::Pair<const Key, Value>>>  // alias for std::allocator
class node_hash_map;

template <class T, class Hash = phmap::priv::hash_default_hash<T>, class Eq = phmap::priv::hash_default_eq<T>,
          class Alloc = phmap::priv::Allocator<T>,  // alias for std::allocator
          size_t N = 4,                             // 2**N submaps
          class Mutex = phmap::NullMutex>           // use std::mutex to enable internal locks
class parallel_flat_hash_set;

template <class K, class V, class Hash = phmap::priv::hash_default_hash<K>, class Eq = phmap::priv::hash_default_eq<K>,
          class Alloc = phmap::priv::Allocator<phmap::priv::Pair<const K, V>>,  // alias for std::allocator
          size_t N = 4,                                                         // 2**N submaps
          class Mutex = phmap::NullMutex>                                       // use std::mutex to enable internal locks
class parallel_flat_hash_map;

template <class T, class Hash = phmap::priv::hash_default_hash<T>, class Eq = phmap::priv::hash_default_eq<T>,
          class Alloc = phmap::priv::Allocator<T>,  // alias for std::allocator
          size_t N = 4,                             // 2**N submaps
          class Mutex = phmap::NullMutex>           // use std::mutex to enable internal locks
class parallel_node_hash_set;

template <class Key, class Value, class Hash = phmap::priv::hash_default_hash<Key>, class Eq = phmap::priv::hash_default_eq<Key>,
          class Alloc = phmap::priv::Allocator<phmap::priv::Pair<const Key, Value>>,  // alias for std::allocator
          size_t N = 4,                                                               // 2**N submaps
          class Mutex = phmap::NullMutex>                                             // use std::mutex to enable internal locks
class parallel_node_hash_map;

// -----------------------------------------------------------------------------
// phmap::parallel_*_hash_* using std::mutex by default
// -----------------------------------------------------------------------------
template <class T, class Hash = phmap::priv::hash_default_hash<T>, class Eq = phmap::priv::hash_default_eq<T>,
          class Alloc = phmap::priv::Allocator<T>, size_t N = 4>
using parallel_flat_hash_set_m = parallel_flat_hash_set<T, Hash, Eq, Alloc, N, std::mutex>;

template <class K, class V, class Hash = phmap::priv::hash_default_hash<K>, class Eq = phmap::priv::hash_default_eq<K>,
          class Alloc = phmap::priv::Allocator<phmap::priv::Pair<const K, V>>, size_t N = 4>
using parallel_flat_hash_map_m = parallel_flat_hash_map<K, V, Hash, Eq, Alloc, N, std::mutex>;

template <class T, class Hash = phmap::priv::hash_default_hash<T>, class Eq = phmap::priv::hash_default_eq<T>,
          class Alloc = phmap::priv::Allocator<T>, size_t N = 4>
using parallel_node_hash_set_m = parallel_node_hash_set<T, Hash, Eq, Alloc, N, std::mutex>;

template <class K, class V, class Hash = phmap::priv::hash_default_hash<K>, class Eq = phmap::priv::hash_default_eq<K>,
          class Alloc = phmap::priv::Allocator<phmap::priv::Pair<const K, V>>, size_t N = 4>
using parallel_node_hash_map_m = parallel_node_hash_map<K, V, Hash, Eq, Alloc, N, std::mutex>;

// ------------- forward declarations for btree containers ----------------------------------
template <typename Key, typename Compare = phmap::Less<Key>, typename Alloc = phmap::Allocator<Key>>
class btree_set;

template <typename Key, typename Compare = phmap::Less<Key>, typename Alloc = phmap::Allocator<Key>>
class btree_multiset;

template <typename Key, typename Value, typename Compare = phmap::Less<Key>,
          typename Alloc = phmap::Allocator<phmap::priv::Pair<const Key, Value>>>
class btree_map;

template <typename Key, typename Value, typename Compare = phmap::Less<Key>,
          typename Alloc = phmap::Allocator<phmap::priv::Pair<const Key, Value>>>
class btree_multimap;

}  // namespace phmap

#ifdef _MSC_VER
#pragma warning(pop)
#endif

#endif  // phmap_fwd_decl_h_guard_