HandleAllocator.cpp

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Author : Stuart Morgan
Date : 2019-08-14 12:25:12
Hash : 9d737966
Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>

src/libANGLE/HandleAllocator.cpp

//
// Copyright 2002 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// HandleAllocator.cpp: Implements the gl::HandleAllocator class, which is used
// to allocate GL handles.

#include "libANGLE/HandleAllocator.h"

#include <algorithm>
#include <functional>

#include "common/debug.h"

namespace gl
{

struct HandleAllocator::HandleRangeComparator
{
    bool operator()(const HandleRange &range, GLuint handle) const { return (range.end < handle); }
};

HandleAllocator::HandleAllocator() : mBaseValue(1), mNextValue(1), mLoggingEnabled(false)
{
    mUnallocatedList.push_back(HandleRange(1, std::numeric_limits<GLuint>::max()));
}

HandleAllocator::HandleAllocator(GLuint maximumHandleValue)
    : mBaseValue(1), mNextValue(1), mLoggingEnabled(false)
{
    mUnallocatedList.push_back(HandleRange(1, maximumHandleValue));
}

HandleAllocator::~HandleAllocator() {}

void HandleAllocator::setBaseHandle(GLuint value)
{
    ASSERT(mBaseValue == mNextValue);
    mBaseValue = value;
    mNextValue = value;
}

GLuint HandleAllocator::allocate()
{
    ASSERT(!mUnallocatedList.empty() || !mReleasedList.empty());

    // Allocate from released list, logarithmic time for pop_heap.
    if (!mReleasedList.empty())
    {
        std::pop_heap(mReleasedList.begin(), mReleasedList.end(), std::greater<GLuint>());
        GLuint reusedHandle = mReleasedList.back();
        mReleasedList.pop_back();

        if (mLoggingEnabled)
        {
            WARN() << "HandleAllocator::allocate reusing " << reusedHandle << std::endl;
        }

        return reusedHandle;
    }

    // Allocate from unallocated list, constant time.
    auto listIt = mUnallocatedList.begin();

    GLuint freeListHandle = listIt->begin;
    ASSERT(freeListHandle > 0);

    if (listIt->begin == listIt->end)
    {
        mUnallocatedList.erase(listIt);
    }
    else
    {
        listIt->begin++;
    }

    if (mLoggingEnabled)
    {
        WARN() << "HandleAllocator::allocate allocating " << freeListHandle << std::endl;
    }

    return freeListHandle;
}

void HandleAllocator::release(GLuint handle)
{
    if (mLoggingEnabled)
    {
        WARN() << "HandleAllocator::release releasing " << handle << std::endl;
    }

    // Add to released list, logarithmic time for push_heap.
    mReleasedList.push_back(handle);
    std::push_heap(mReleasedList.begin(), mReleasedList.end(), std::greater<GLuint>());
}

void HandleAllocator::reserve(GLuint handle)
{
    if (mLoggingEnabled)
    {
        WARN() << "HandleAllocator::reserve reserving " << handle << std::endl;
    }

    // Clear from released list -- might be a slow operation.
    if (!mReleasedList.empty())
    {
        auto releasedIt = std::find(mReleasedList.begin(), mReleasedList.end(), handle);
        if (releasedIt != mReleasedList.end())
        {
            mReleasedList.erase(releasedIt);
            std::make_heap(mReleasedList.begin(), mReleasedList.end(), std::greater<GLuint>());
            return;
        }
    }

    // Not in released list, reserve in the unallocated list.
    auto boundIt = std::lower_bound(mUnallocatedList.begin(), mUnallocatedList.end(), handle,
                                    HandleRangeComparator());

    ASSERT(boundIt != mUnallocatedList.end());

    GLuint begin = boundIt->begin;
    GLuint end   = boundIt->end;

    if (handle == begin || handle == end)
    {
        if (begin == end)
        {
            mUnallocatedList.erase(boundIt);
        }
        else if (handle == begin)
        {
            boundIt->begin++;
        }
        else
        {
            ASSERT(handle == end);
            boundIt->end--;
        }
        return;
    }

    ASSERT(begin < handle && handle < end);

    // need to split the range
    auto placementIt = mUnallocatedList.erase(boundIt);
    placementIt      = mUnallocatedList.insert(placementIt, HandleRange(handle + 1, end));
    mUnallocatedList.insert(placementIt, HandleRange(begin, handle - 1));
}

void HandleAllocator::reset()
{
    mUnallocatedList.clear();
    mUnallocatedList.push_back(HandleRange(1, std::numeric_limits<GLuint>::max()));
    mReleasedList.clear();
    mBaseValue = 1;
    mNextValue = 1;
}

void HandleAllocator::enableLogging(bool enabled)
{
    mLoggingEnabled = enabled;
}

}  // namespace gl

kc3-lang/angle/src/libANGLE/HandleAllocator.cpp

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kc3-lang/angle /src/libANGLE/HandleAllocator.cpp