HandleRangeAllocator.cpp

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Author : Jamie Madill
Date : 2016-10-31 12:17:19
Hash : 60e6edfa
Message : Make ASSERT reference the conditional expression. This should prevent further unexpected bot breakage due to unreferenced variables in the ASSERT expression. Also remove the no longer needed variable referencing macro. BUG=angleproject:1586 Change-Id: I127695165bdfe39c51fe8d17e00daf6bf2fa8252 Reviewed-on: https://chromium-review.googlesource.com/404948 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>

src/libANGLE/HandleRangeAllocator.cpp

//
// Copyright (c) 2016 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.
//

// HandleRangeAllocator.cpp : Implementation for HandleRangeAllocator.h

#include "libANGLE/HandleRangeAllocator.h"

#include <algorithm>
#include <limits>
#include <utility>

#include "common/angleutils.h"
#include "common/debug.h"

namespace gl
{

const GLuint HandleRangeAllocator::kInvalidHandle = 0;

HandleRangeAllocator::HandleRangeAllocator()
{
    // Simplify the code by making sure that lower_bound(id) never
    // returns the beginning of the map, if id is valid (eg != kInvalidHandle).
    mUsed.insert(std::make_pair(0u, 0u));
}

GLuint HandleRangeAllocator::allocate()
{
    return allocateRange(1u);
}

GLuint HandleRangeAllocator::allocateAtOrAbove(GLuint wanted)
{
    if (wanted == 0u || wanted == 1u)
        return allocateRange(1u);

    auto current = mUsed.lower_bound(wanted);
    auto next = current;
    if (current == mUsed.end() || current->first > wanted)
    {
        current--;
    }
    else
    {
        next++;
    }

    GLuint firstId = current->first;
    GLuint lastId = current->second;
    ASSERT(wanted >= firstId);

    if (wanted - 1u <= lastId)
    {
        // Append to current range.
        lastId++;
        if (lastId == 0)
        {
            // The increment overflowed.
            return allocateRange(1u);
        }

        current->second = lastId;

        if (next != mUsed.end() && next->first - 1u == lastId)
        {
            // Merge with next range.
            current->second = next->second;
            mUsed.erase(next);
        }
        return lastId;
    }
    else if (next != mUsed.end() && next->first - 1u == wanted)
    {
        // Prepend to next range.
        GLuint lastExisting = next->second;
        mUsed.erase(next);
        mUsed.insert(std::make_pair(wanted, lastExisting));
        return wanted;
    }
    mUsed.insert(std::make_pair(wanted, wanted));
    return wanted;
}

GLuint HandleRangeAllocator::allocateRange(GLuint range)
{
    ASSERT(range != 0);

    auto current = mUsed.begin();
    auto next    = current;

    while (++next != mUsed.end())
    {
        if (next->first - current->second > range)
            break;
        current = next;
    }
    const GLuint firstId = current->second + 1u;
    const GLuint lastId  = firstId + range - 1u;

    // deal with wraparound
    if (firstId == 0u || lastId < firstId)
        return kInvalidHandle;

    current->second = lastId;

    if (next != mUsed.end() && next->first - 1u == lastId)
    {
        // merge with next range
        current->second = next->second;
        mUsed.erase(next);
    }
    return firstId;
}

bool HandleRangeAllocator::markAsUsed(GLuint handle)
{
    ASSERT(handle);
    auto current = mUsed.lower_bound(handle);
    if (current != mUsed.end() && current->first == handle)
        return false;

    auto next = current;
    --current;

    if (current->second >= handle)
        return false;

    ASSERT(current->first < handle && current->second < handle);

    if (current->second + 1u == handle)
    {
        // Append to current range.
        current->second = handle;
        if (next != mUsed.end() && next->first - 1u == handle)
        {
            // Merge with next range.
            current->second = next->second;
            mUsed.erase(next);
        }
        return true;
    }
    else if (next != mUsed.end() && next->first - 1u == handle)
    {
        // Prepend to next range.
        GLuint lastExisting = next->second;
        mUsed.erase(next);
        mUsed.insert(std::make_pair(handle, lastExisting));
        return true;
    }

    mUsed.insert(std::make_pair(handle, handle));
    return true;
}

void HandleRangeAllocator::release(GLuint handle)
{
    releaseRange(handle, 1u);
}

void HandleRangeAllocator::releaseRange(GLuint first, GLuint range)
{
    if (range == 0u || (first == 0u && range == 1u))
        return;

    if (first == 0u)
    {
        first++;
        range--;
    }

    GLuint last = first + range - 1u;
    if (last < first)
        last = std::numeric_limits<GLuint>::max();

    while (true)
    {
        auto current = mUsed.lower_bound(last);
        if (current == mUsed.end() || current->first > last)
            --current;

        if (current->second < first)
            return;

        if (current->first >= first)
        {
            const GLuint lastExisting = current->second;
            mUsed.erase(current);
            if (last < lastExisting)
            {
                mUsed.insert(std::make_pair(last + 1u, lastExisting));
            }
        }
        else if (current->second <= last)
        {
            current->second = first - 1u;
        }
        else
        {
            ASSERT(current->first < first && current->second > last);
            const GLuint lastExisting = current->second;
            current->second = first - 1u;
            mUsed.insert(std::make_pair(last + 1u, lastExisting));
        }
    }
}

bool HandleRangeAllocator::isUsed(GLuint handle) const
{
    if (handle == kInvalidHandle)
        return false;

    auto current = mUsed.lower_bound(handle);
    if (current != mUsed.end())
    {
        if (current->first == handle)
            return true;
    }
    --current;
    return current->second >= handle;
}

}  // namespace gl

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

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