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// Copyright (c) 2012 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.
// This file contains the definition of the IdAllocator class.
#include <stdint.h>
#include <set>
#include <utility>
#include "base/compiler_specific.h"
#include "base/macros.h"
#include "gpu/gpu_export.h"
namespace gpu {
// A resource ID, key to the resource maps.
typedef uint32_t ResourceId;
// Invalid resource ID.
static const ResourceId kInvalidResource = 0u;
// A class to manage the allocation of resource IDs.
class GPU_EXPORT IdAllocator {
// Allocates a new resource ID.
ResourceId AllocateID();
// Allocates an Id starting at or above desired_id.
// Note: may wrap if it starts near limit.
ResourceId AllocateIDAtOrAbove(ResourceId desired_id);
// Marks an id as used. Returns false if id was already used.
bool MarkAsUsed(ResourceId id);
// Frees a resource ID.
void FreeID(ResourceId id);
// Checks whether or not a resource ID is in use.
bool InUse(ResourceId id) const;
// TODO(gman): This would work much better with ranges or a hash table.
typedef std::set<ResourceId> ResourceIdSet;
// The highest ID on the used list.
ResourceId LastUsedId() const;
// Lowest ID that isn't on the used list. This is slow, use as a last resort.
ResourceId FindFirstUnusedId() const;
ResourceIdSet used_ids_;
ResourceIdSet free_ids_;
} // namespace gpu