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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_GFX_SEQUENTIAL_ID_GENERATOR_H_
#define UI_GFX_SEQUENTIAL_ID_GENERATOR_H_
#include <stdint.h>
#include <map>
#include <unordered_map>
#include "base/component_export.h"
namespace ui {
// This is used to generate a series of sequential ID numbers in a way that a
// new ID is always the lowest possible ID in the sequence.
class COMPONENT_EXPORT(GFX) SequentialIDGenerator {
public:
// Creates a new generator with the specified lower bound for the IDs.
explicit SequentialIDGenerator(uint32_t min_id);
SequentialIDGenerator(const SequentialIDGenerator&) = delete;
SequentialIDGenerator& operator=(const SequentialIDGenerator&) = delete;
~SequentialIDGenerator();
// Generates a unique ID to represent |number|. The generated ID is the
// smallest available ID greater than or equal to the |min_id| specified
// during creation of the generator.
uint32_t GetGeneratedID(uint32_t number);
// Checks to see if the generator currently has a unique ID generated for
// |number|.
bool HasGeneratedIDFor(uint32_t number) const;
// Removes the ID previously generated for |number| by calling
// |GetGeneratedID()| - does nothing if the number is not mapped.
void ReleaseNumber(uint32_t number);
// Releases ID previously generated by calling |GetGeneratedID()|. Does
// nothing if the ID is not mapped.
void ReleaseID(uint32_t id);
void ResetForTest();
private:
typedef std::unordered_map<uint32_t, uint32_t> IDMap;
uint32_t GetNextAvailableID();
void UpdateNextAvailableIDAfterRelease(uint32_t id);
IDMap number_to_id_;
IDMap id_to_number_;
const uint32_t min_id_;
uint32_t min_available_id_;
};
} // namespace ui
#endif // UI_GFX_SEQUENTIAL_ID_GENERATOR_H_
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