sky/engine/wtf/BitArray.h

/*
 * Copyright (C) 2012 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef SKY_ENGINE_WTF_BITARRAY_H_
#define SKY_ENGINE_WTF_BITARRAY_H_

#include <string.h>
#include "sky/engine/wtf/Assertions.h"

namespace WTF {

template<unsigned arraySize>
class BitArray {
public:
    BitArray(bool value = false)
    {
        memset(m_data, value ? 0xFF : 0, sizeof(m_data));
    }

    void set(unsigned index)
    {
        ASSERT_WITH_SECURITY_IMPLICATION(index < arraySize);
        m_data[index / 8] |= 1 << (index & 7);
    }

    void clear(unsigned index)
    {
        ASSERT_WITH_SECURITY_IMPLICATION(index < arraySize);
        m_data[index / 8] &= ~(1 << (index & 7));
    }

    bool get(unsigned index) const
    {
        ASSERT_WITH_SECURITY_IMPLICATION(index < arraySize);
        return !!(m_data[index / 8] & (1 << (index & 7)));
    }

private:
    unsigned char m_data[arraySize / 8 + 1];
};

} // namespace WTF

using WTF::BitArray;

#endif  // SKY_ENGINE_WTF_BITARRAY_H_