cc/surfaces/surface_id.h

// Copyright 2014 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 CC_SURFACES_SURFACE_ID_H_
#define CC_SURFACES_SURFACE_ID_H_

#include <stddef.h>
#include <stdint.h>

#include <functional>

namespace cc {

struct SurfaceId {
  SurfaceId() : id(0) {}
  explicit SurfaceId(uint64_t id) : id(id) {}

  bool is_null() const { return id == 0; }

  // See SurfaceIdAllocator::GenerateId.
  uint32_t id_namespace() const { return id >> 32; }

  uint64_t id;
};

inline bool operator==(const SurfaceId& a, const SurfaceId& b) {
  return a.id == b.id;
}

inline bool operator!=(const SurfaceId& a, const SurfaceId& b) {
  return !(a == b);
}

inline bool operator<(const SurfaceId& a, const SurfaceId& b) {
  return a.id < b.id;
}

struct SurfaceIdHash {
  size_t operator()(const SurfaceId& key) const {
    return std::hash<uint64_t>()(key.id);
  }
};

}  // namespace cc

#endif  // CC_SURFACES_SURFACE_ID_H_