/*
 * Copyright (C) 2016 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 XLargeRange_h
#define XLargeRange_h

#include "VMState.h"

namespace bmalloc {

class XLargeRange : public Range {
public:
    XLargeRange()
        : Range()
        , m_vmState(VMState::Virtual)
    {
    }

    XLargeRange(void* begin, size_t size, VMState vmState)
        : Range(begin, size)
        , m_vmState(vmState)
    {
    }
    
    VMState vmState() const { return m_vmState; }
    void setVMState(VMState vmState) { m_vmState = vmState; }

    std::pair<XLargeRange, XLargeRange> split(size_t) const;

private:
    VMState m_vmState;
};

inline bool canMerge(const XLargeRange& a, const XLargeRange& b)
{
    if (a.end() == b.begin())
        return true;
    
    if (b.end() == a.begin())
        return true;
    
    return false;
}

inline XLargeRange merge(const XLargeRange& a, const XLargeRange& b)
{
    return XLargeRange(
        std::min(a.begin(), b.begin()),
        a.size() + b.size(),
        merge(a.vmState(), b.vmState()));
}

inline std::pair<XLargeRange, XLargeRange> XLargeRange::split(size_t size) const
{
    BASSERT(size <= this->size());

    XLargeRange left(begin(), size, vmState());
    XLargeRange right(left.end(), this->size() - size, vmState());
    return std::make_pair(left, right);
}

} // namespace bmalloc

#endif // XLargeRange_h
