qmap.cpp

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#include "qmap.h"

#include <stdlib.h>

#ifdef QT_QMAP_DEBUG
# include <qstring.h>
# include <qvector.h>
#endif

QT_BEGIN_NAMESPACE

QMapData QMapData::shared_null = {
    &shared_null,
    { &shared_null, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    Q_BASIC_ATOMIC_INITIALIZER(1), 0, 0, 0, false, true, false, 0
};

QMapData *QMapData::createData()
{
    return createData(0);
}

QMapData *QMapData::createData(int alignment)
{
    QMapData *d = new QMapData;
    Q_CHECK_PTR(d);
    Node *e = reinterpret_cast<Node *>(d);
    e->backward = e;
    e->forward[0] = e;
    d->ref = 1;
    d->topLevel = 0;
    d->size = 0;
    d->randomBits = 0;
    d->insertInOrder = false;
    d->sharable = true;
    d->strictAlignment = alignment > 8;
    d->reserved = 0;
    return d;
}

void QMapData::continueFreeData(int offset)
{
    Node *e = reinterpret_cast<Node *>(this);
    Node *cur = e->forward[0];
    Node *prev;
    while (cur != e) {
        prev = cur;
        cur = cur->forward[0];
        if (strictAlignment)
            qFreeAligned(reinterpret_cast<char *>(prev) - offset);
        else
            qFree(reinterpret_cast<char *>(prev) - offset);
    }
    delete this;
}

QMapData::Node *QMapData::node_create(Node *update[], int offset)
{
    return node_create(update, offset, 0);
}

QMapData::Node *QMapData::node_create(Node *update[], int offset, int alignment)
{
    int level = 0;
    uint mask = (1 << Sparseness) - 1;

    while ((randomBits & mask) == mask && level < LastLevel) {
        ++level;
        mask <<= Sparseness;
    }

    if (level > topLevel) {
        Node *e = reinterpret_cast<Node *>(this);
        level = ++topLevel;
        e->forward[level] = e;
        update[level] = e;
    }

    ++randomBits;
    if (level == 3 && !insertInOrder)
        randomBits = qrand();

    void *concreteNode = strictAlignment ?
                         qMallocAligned(offset + sizeof(Node) + level * sizeof(Node *), alignment) :
                         qMalloc(offset + sizeof(Node) + level * sizeof(Node *));
    Q_CHECK_PTR(concreteNode);

    Node *abstractNode = reinterpret_cast<Node *>(reinterpret_cast<char *>(concreteNode) + offset);

    abstractNode->backward = update[0];
    update[0]->forward[0]->backward = abstractNode;

    for (int i = level; i >= 0; i--) {
        abstractNode->forward[i] = update[i]->forward[i];
        update[i]->forward[i] = abstractNode;
        update[i] = abstractNode;
    }
    ++size;
    return abstractNode;
}

void QMapData::node_delete(Node *update[], int offset, Node *node)
{
    node->forward[0]->backward = node->backward;

    for (int i = 0; i <= topLevel; ++i) {
        if (update[i]->forward[i] != node)
            break;
        update[i]->forward[i] = node->forward[i];
    }
    --size;
    if (strictAlignment)
        qFreeAligned(reinterpret_cast<char *>(node) - offset);
    else
        qFree(reinterpret_cast<char *>(node) - offset);
}

#ifdef QT_QMAP_DEBUG

uint QMapData::adjust_ptr(Node *node)
{
    if (node == reinterpret_cast<Node *>(this)) {
       return (uint)0xDEADBEEF;
    } else {
        return (uint)node;
    }
}

void QMapData::dump()
{
    qDebug("Map data (ref = %d, size = %d, randomBits = %#.8x)", int(ref), size, randomBits);

    QString preOutput;
    QVector<QString> output(topLevel + 1);
    Node *e = reinterpret_cast<Node *>(this);

    QString str;
    str.sprintf("    %.8x", adjust_ptr(reinterpret_cast<Node *>(this)));
    preOutput += str;

    Node *update[LastLevel + 1];
    for (int i = 0; i <= topLevel; ++i) {
        str.sprintf("%d: [%.8x] -", i, adjust_ptr(reinterpret_cast<Node *>(forward[i])));
        output[i] += str;
        update[i] = reinterpret_cast<Node *>(forward[i]);
    }

    Node *node = reinterpret_cast<Node *>(forward[0]);
    while (node != e) {
        int level = 0;
        while (level < topLevel && update[level + 1] == node)
            ++level;

        str.sprintf("       %.8x", adjust_ptr(node));
        preOutput += str;

        for (int i = 0; i <= level; ++i) {
            str.sprintf("-> [%.8x] -", adjust_ptr(node->forward[i]));
            output[i] += str;
            update[i] = node->forward[i];
        }
        for (int j = level + 1; j <= topLevel; ++j)
            output[j] += QLatin1String("---------------");
        node = node->forward[0];
    }

    qDebug("%s", preOutput.ascii());
    for (int i = 0; i <= topLevel; ++i)
        qDebug("%s", output[i].ascii());
}
#endif

QT_END_NAMESPACE