qbbbuffer.cpp

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//#define QBBBUFFER_DEBUG


#include "qbbbuffer.h"

#include <QDebug>

#include <errno.h>
#include <sys/mman.h>

QT_BEGIN_NAMESPACE

QBBBuffer::QBBBuffer()
    : mBuffer(NULL)
{
#if defined(QBBBUFFER_DEBUG)
    qDebug() << "QBBBuffer::QBBBuffer - empty";
#endif
}

QBBBuffer::QBBBuffer(screen_buffer_t buffer)
    : mBuffer(buffer)
{
#if defined(QBBBUFFER_DEBUG)
    qDebug() << "QBBBuffer::QBBBuffer - normal";
#endif

    // get size of buffer
    errno = 0;
    int size[2];
    int result = screen_get_buffer_property_iv(buffer, SCREEN_PROPERTY_BUFFER_SIZE, size);
    if (result != 0) {
        qFatal("QBB: failed to query buffer size, errno=%d", errno);
    }

    // get stride of buffer
    errno = 0;
    int stride;
    result = screen_get_buffer_property_iv(buffer, SCREEN_PROPERTY_STRIDE, &stride);
    if (result != 0) {
        qFatal("QBB: failed to query buffer stride, errno=%d", errno);
    }

    // get access to buffer's data
    errno = 0;
    uchar* dataPtr = NULL;
    result = screen_get_buffer_property_pv(buffer, SCREEN_PROPERTY_POINTER, (void **)&dataPtr);
    if (result != 0) {
        qFatal("QBB: failed to query buffer pointer, errno=%d", errno);
    }
    if (dataPtr == NULL) {
        qFatal("QBB: buffer pointer is NULL, errno=%d", errno);
    }

    // get format of buffer
    errno = 0;
    int screenFormat;
    result = screen_get_buffer_property_iv(buffer, SCREEN_PROPERTY_FORMAT, &screenFormat);
    if (result != 0) {
        qFatal("QBB: failed to query buffer format, errno=%d", errno);
    }

    // convert screen format to QImage format
    QImage::Format imageFormat = QImage::Format_Invalid;
    switch (screenFormat) {
    case SCREEN_FORMAT_RGBX4444:
        imageFormat = QImage::Format_RGB444;
        break;
    case SCREEN_FORMAT_RGBA4444:
        imageFormat = QImage::Format_ARGB4444_Premultiplied;
        break;
    case SCREEN_FORMAT_RGBX5551:
        imageFormat = QImage::Format_RGB555;
        break;
    case SCREEN_FORMAT_RGB565:
        imageFormat = QImage::Format_RGB16;
        break;
    case SCREEN_FORMAT_RGBX8888:
        imageFormat = QImage::Format_RGB32;
        break;
    case SCREEN_FORMAT_RGBA8888:
        imageFormat = QImage::Format_ARGB32_Premultiplied;
        break;
    default:
        qFatal("QBB: unsupported buffer format, format=%d", screenFormat);
    }

    // wrap buffer in an image
    mImage = QImage(dataPtr, size[0], size[1], stride, imageFormat);
}

QBBBuffer::QBBBuffer(const QBBBuffer &other)
    : mBuffer(other.mBuffer),
      mImage(other.mImage)
{
#if defined(QBBBUFFER_DEBUG)
    qDebug() << "QBBBuffer::QBBBuffer - copy";
#endif
}

QBBBuffer::~QBBBuffer()
{
#if defined(QBBBUFFER_DEBUG)
    qDebug() << "QBBBuffer::~QBBBuffer";
#endif
}

void QBBBuffer::invalidateInCache()
{
#if defined(QBBBUFFER_DEBUG)
    qDebug() << "QBBBuffer::invalidateInCache";
#endif

    // verify native buffer exists
    if (mBuffer == NULL) {
        qFatal("QBB: can't invalidate cache for null buffer");
    }

    // evict buffer's data from cache
    errno = 0;
    int result = msync(mImage.bits(), mImage.height() * mImage.bytesPerLine(), MS_INVALIDATE | MS_CACHE_ONLY);
    if (result != 0) {
        qFatal("QBB: failed to invalidate cache, errno=%d", errno);
    }
}

QT_END_NAMESPACE