chromium/third_party/skia/src/core/SkTHash.h

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkTHash_DEFINED
#define SkTHash_DEFINED

#include "include/core/SkTypes.h"
#include "src/base/SkMathPriv.h"
#include "src/core/SkChecksum.h"

#include <initializer_list>
#include <memory>
#include <new>
#include <type_traits>
#include <utility>

namespace skia_private {

// Before trying to use THashTable, look below to see if THashMap or THashSet works for you.
// They're easier to use, usually perform the same, and have fewer sharp edges.

// T and K are treated as ordinary copyable C++ types.
// Traits must have:
//   - static K GetKey(T)
//   - static uint32_t Hash(K)
// If the key is large and stored inside T, you may want to make K a const&.
// Similarly, if T is large you might want it to be a pointer.
template <typename T, typename K, typename Traits = T>
class THashTable { … };

// Maps K->V.  A more user-friendly wrapper around THashTable, suitable for most use cases.
// K and V are treated as ordinary copyable C++ types, with no assumed relationship between the two.
template <typename K, typename V, typename HashK = SkGoodHash>
class THashMap { … };

// A set of T.  T is treated as an ordinary copyable C++ type.
template <typename T, typename HashT = SkGoodHash>
class THashSet { … };

}  // namespace skia_private

#endif  // SkTHash_DEFINED