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#include "private/qbmphandler_p.h"

#ifndef QT_NO_IMAGEFORMAT_BMP

#include <qimage.h>

#include <qvariant.h>

#include <qvector.h>

QT_BEGIN_NAMESPACE

static void swapPixel01(QImage *image)        // 1-bpp: swap 0 and 1 pixels

{

    int i;

        register uint *p = (uint *)image->bits();

        for (i=0; i<nbytes/4; i++) {

            *p = ~*p;

            p++;

        }

        uchar *p2 = (uchar *)p;

        for (i=0; i<(nbytes&3); i++) {

            *p2 = ~*p2;

            p2++;

        }

        QRgb t = image->color(0);                // swap color 0 and 1

        image->setColor(0, image->color(1));

        image->setColor(1, t);

    }

}

/*

    QImageIO::defineIOHandler("BMP", "^BM", 0,

                               read_bmp_image, write_bmp_image);

*/

/*****************************************************************************

  BMP (DIB) image read/write functions

 *****************************************************************************/

const int BMP_FILEHDR_SIZE = 14;                // size of BMP_FILEHDR data

static QDataStream &operator>>(QDataStream &s, BMP_FILEHDR &bf)

{                                                // read file header

    s.readRawData(bf.bfType, 2);

    s >> bf.bfSize >> bf.bfReserved1 >> bf.bfReserved2 >> bf.bfOffBits;

    return s;

}

static QDataStream &operator<<(QDataStream &s, const BMP_FILEHDR &bf)

{                                                // write file header

    s.writeRawData(bf.bfType, 2);

    s << bf.bfSize << bf.bfReserved1 << bf.bfReserved2 << bf.bfOffBits;

    return s;

}

const int BMP_OLD  = 12;                        // old Windows/OS2 BMP size

const int BMP_WIN  = 40;                        // new Windows BMP size

const int BMP_OS2  = 64;                        // new OS/2 BMP size

const int BMP_RGB  = 0;                                // no compression

const int BMP_RLE8 = 1;                                // run-length encoded, 8 bits

const int BMP_RLE4 = 2;                                // run-length encoded, 4 bits

const int BMP_BITFIELDS = 3;                        // RGB values encoded in data as bit-fields

static QDataStream &operator>>(QDataStream &s, BMP_INFOHDR &bi)

{

    s >> bi.biSize;

    if (bi.biSize == BMP_WIN || bi.biSize == BMP_OS2) {

        s >> bi.biWidth >> bi.biHeight >> bi.biPlanes >> bi.biBitCount;

        s >> bi.biCompression >> bi.biSizeImage;

        s >> bi.biXPelsPerMeter >> bi.biYPelsPerMeter;

        s >> bi.biClrUsed >> bi.biClrImportant;

    }

    else {                                        // probably old Windows format

        qint16 w, h;

        s >> w >> h >> bi.biPlanes >> bi.biBitCount;

        bi.biWidth  = w;

        bi.biHeight = h;

        bi.biCompression = BMP_RGB;                // no compression

        bi.biSizeImage = 0;

        bi.biXPelsPerMeter = bi.biYPelsPerMeter = 0;

        bi.biClrUsed = bi.biClrImportant = 0;

    }

    return s;

}

static QDataStream &operator<<(QDataStream &s, const BMP_INFOHDR &bi)

{

    s << bi.biSize;

    s << bi.biWidth << bi.biHeight;

    s << bi.biPlanes;

    s << bi.biBitCount;

    s << bi.biCompression;

    s << bi.biSizeImage;

    s << bi.biXPelsPerMeter << bi.biYPelsPerMeter;

    s << bi.biClrUsed << bi.biClrImportant;

    return s;

}

static int calc_shift(int mask)

{

    int result = 0;

    while (!(mask & 1)) {

        result++;

        mask >>= 1;

    }

    return result;

}

static bool read_dib_fileheader(QDataStream &s, BMP_FILEHDR &bf)

{

    // read BMP file header

    s >> bf;

    if (s.status() != QDataStream::Ok)

        return false;

    // check header

    if (qstrncmp(bf.bfType,"BM",2) != 0)

        return false;

    return true;

}

static bool read_dib_infoheader(QDataStream &s, BMP_INFOHDR &bi)

{

    s >> bi;                                        // read BMP info header

    if (s.status() != QDataStream::Ok)

        return false;

    int nbits = bi.biBitCount;

    int comp = bi.biCompression;

    if (!(nbits == 1 || nbits == 4 || nbits == 8 || nbits == 16 || nbits == 24 || nbits == 32) ||

        bi.biPlanes != 1 || comp > BMP_BITFIELDS)

        return false;                                        // weird BMP image

    if (!(comp == BMP_RGB || (nbits == 4 && comp == BMP_RLE4) ||

        (nbits == 8 && comp == BMP_RLE8) || ((nbits == 16 || nbits == 32) && comp == BMP_BITFIELDS)))

         return false;                                // weird compression type

    return true;

}

static bool read_dib_body(QDataStream &s, const BMP_INFOHDR &bi, int offset, int startpos, QImage &image)

{

    QIODevice* d = s.device();

    if (d->atEnd())                                // end of stream/file

        return false;

#if 0

    qDebug("offset...........%d", offset);

    qDebug("startpos.........%d", startpos);

    qDebug("biSize...........%d", bi.biSize);

    qDebug("biWidth..........%d", bi.biWidth);

    qDebug("biHeight.........%d", bi.biHeight);

    qDebug("biPlanes.........%d", bi.biPlanes);

    qDebug("biBitCount.......%d", bi.biBitCount);

    qDebug("biCompression....%d", bi.biCompression);

    qDebug("biSizeImage......%d", bi.biSizeImage);

    qDebug("biXPelsPerMeter..%d", bi.biXPelsPerMeter);

    qDebug("biYPelsPerMeter..%d", bi.biYPelsPerMeter);

    qDebug("biClrUsed........%d", bi.biClrUsed);

    qDebug("biClrImportant...%d", bi.biClrImportant);

#endif

    int w = bi.biWidth,         h = bi.biHeight,  nbits = bi.biBitCount;

    int t = bi.biSize,         comp = bi.biCompression;

    int red_mask = 0;

    int green_mask = 0;

    int blue_mask = 0;

    int red_shift = 0;

    int green_shift = 0;

    int blue_shift = 0;

    int red_scale = 0;

    int green_scale = 0;

    int blue_scale = 0;

    int ncols = 0;

    int depth = 0;

    QImage::Format format;

    switch (nbits) {

        case 32:

        case 24:

        case 16:

            depth = 32;

            format = QImage::Format_RGB32;

            break;

        case 8:

        case 4:

            depth = 8;

            format = QImage::Format_Indexed8;

            break;

        default:

            depth = 1;

            format = QImage::Format_Mono;

    }

    if (bi.biHeight < 0)

        h = -h;                  // support images with negative height

    if (image.size() != QSize(w, h) || image.format() != format) {

        image = QImage(w, h, format);

        if (image.isNull())                        // could not create image

            return false;

    }

    if (depth != 32) {

        ncols = bi.biClrUsed ? bi.biClrUsed : 1 << nbits;

    }

    image.setDotsPerMeterX(bi.biXPelsPerMeter);

    image.setDotsPerMeterY(bi.biYPelsPerMeter);

    if (!d->isSequential())

        d->seek(startpos + BMP_FILEHDR_SIZE + bi.biSize); // goto start of colormap

    if (ncols > 0) {                                // read color table

        uchar rgb[4];

        int   rgb_len = t == BMP_OLD ? 3 : 4;

        for (int i=0; i<ncols; i++) {

            if (d->read((char *)rgb, rgb_len) != rgb_len)

                return false;

            image.setColor(i, qRgb(rgb[2],rgb[1],rgb[0]));

            if (d->atEnd())                        // truncated file

                return false;

        }

    } else if (comp == BMP_BITFIELDS && (nbits == 16 || nbits == 32)) {

        if (d->read((char *)&red_mask, sizeof(red_mask)) != sizeof(red_mask))

            return false;

        if (d->read((char *)&green_mask, sizeof(green_mask)) != sizeof(green_mask))

            return false;

        if (d->read((char *)&blue_mask, sizeof(blue_mask)) != sizeof(blue_mask))

            return false;

        red_shift = calc_shift(red_mask);

        red_scale = 256 / ((red_mask >> red_shift) + 1);

        green_shift = calc_shift(green_mask);

        green_scale = 256 / ((green_mask >> green_shift) + 1);

        blue_shift = calc_shift(blue_mask);

        blue_scale = 256 / ((blue_mask >> blue_shift) + 1);

    } else if (comp == BMP_RGB && (nbits == 24 || nbits == 32)) {

        blue_mask = 0x000000ff;

        green_mask = 0x0000ff00;

        red_mask = 0x00ff0000;

        blue_shift = 0;

        green_shift = 8;

        red_shift = 16;

        blue_scale = green_scale = red_scale = 1;

    } else if (comp == BMP_RGB && nbits == 16) {

        blue_mask = 0x001f;

        green_mask = 0x03e0;

        red_mask = 0x7c00;

        blue_shift = 0;

        green_shift = 2;

        red_shift = 7;

        red_scale = 1;

        green_scale = 1;

        blue_scale = 8;

    }

    // offset can be bogus, be careful

    if (offset>=0 && startpos + offset > d->pos()) {

        if (!d->isSequential())

            d->seek(startpos + offset);                // start of image data

    }

    int             bpl = image.bytesPerLine();

    uchar *data = image.bits();

    if (nbits == 1) {                                // 1 bit BMP image

        while (--h >= 0) {

            if (d->read((char*)(data + h*bpl), bpl) != bpl)

                break;

        }

        if (ncols == 2 && qGray(image.color(0)) < qGray(image.color(1)))

            swapPixel01(&image);                // pixel 0 is white!

    }

    else if (nbits == 4) {                        // 4 bit BMP image

        int    buflen = ((w+7)/8)*4;

        uchar *buf    = new uchar[buflen];

        if (comp == BMP_RLE4) {                // run length compression

            int x=0, y=0, c, i;

            quint8 b;

            register uchar *p = data + (h-1)*bpl;

            const uchar *endp = p + w;

            while (y < h) {

                if (!d->getChar((char *)&b))

                    break;

                if (b == 0) {                        // escape code

                    if (!d->getChar((char *)&b) || b == 1) {

                        y = h;                // exit loop

                    } else switch (b) {

                        case 0:                        // end of line

                            x = 0;

                            y++;

                            p = data + (h-y-1)*bpl;

                            break;

                        case 2:                        // delta (jump)

                        {

                            quint8 tmp;

                            d->getChar((char *)&tmp);

                            x += tmp;

                            d->getChar((char *)&tmp);

                            y += tmp;

                        }

                            // Protection

                            if ((uint)x >= (uint)w)

                                x = w-1;

                            if ((uint)y >= (uint)h)

                                y = h-1;

                            p = data + (h-y-1)*bpl + x;

                            break;

                        default:                // absolute mode

                            // Protection

                            if (p + b > endp)

                                b = endp-p;

                            i = (c = b)/2;

                            while (i--) {

                                d->getChar((char *)&b);

                                *p++ = b >> 4;

                                *p++ = b & 0x0f;

                            }

                            if (c & 1) {

                                unsigned char tmp;

                                d->getChar((char *)&tmp);

                                *p++ = tmp >> 4;

                            }

                            if ((((c & 3) + 1) & 2) == 2)

                                d->getChar(0);        // align on word boundary

                            x += c;

                    }

                } else {                        // encoded mode

                    // Protection

                    if (p + b > endp)

                        b = endp-p;

                    i = (c = b)/2;

                    d->getChar((char *)&b);                // 2 pixels to be repeated

                    while (i--) {

                        *p++ = b >> 4;

                        *p++ = b & 0x0f;

                    }

                    if (c & 1)

                        *p++ = b >> 4;

                    x += c;

                }

            }

        } else if (comp == BMP_RGB) {                // no compression

            memset(data, 0, h*bpl);

            while (--h >= 0) {

                if (d->read((char*)buf,buflen) != buflen)

                    break;

                register uchar *p = data + h*bpl;

                uchar *b = buf;

                for (int i=0; i<w/2; i++) {        // convert nibbles to bytes

                    *p++ = *b >> 4;

                    *p++ = *b++ & 0x0f;

                }

                if (w & 1)                        // the last nibble

                    *p = *b >> 4;

            }

        }

        delete [] buf;

    }

    else if (nbits == 8) {                        // 8 bit BMP image

        if (comp == BMP_RLE8) {                // run length compression

            int x=0, y=0;

            quint8 b;

            register uchar *p = data + (h-1)*bpl;

            const uchar *endp = p + w;

            while (y < h) {

                if (!d->getChar((char *)&b))

                    break;

                if (b == 0) {                        // escape code

                    if (!d->getChar((char *)&b) || b == 1) {

                            y = h;                // exit loop

                    } else switch (b) {

                        case 0:                        // end of line

                            x = 0;

                            y++;

                            p = data + (h-y-1)*bpl;

                            break;

                        case 2:                        // delta (jump)

                            // Protection

                            if ((uint)x >= (uint)w)

                                x = w-1;

                            if ((uint)y >= (uint)h)

                                y = h-1;

                            {

                                quint8 tmp;

                                d->getChar((char *)&tmp);

                                x += tmp;

                                d->getChar((char *)&tmp);

                                y += tmp;

                            }

                            p = data + (h-y-1)*bpl + x;

                            break;

                        default:                // absolute mode

                            // Protection

                            if (p + b > endp)

                                b = endp-p;

                            if (d->read((char *)p, b) != b)

                                return false;

                            if ((b & 1) == 1)

                                d->getChar(0);        // align on word boundary

                            x += b;

                            p += b;

                    }

                } else {                        // encoded mode

                    // Protection

                    if (p + b > endp)

                        b = endp-p;

                    char tmp;

                    d->getChar(&tmp);

                    memset(p, tmp, b); // repeat pixel

                    x += b;

                    p += b;

                }

            }

        } else if (comp == BMP_RGB) {                // uncompressed

            while (--h >= 0) {

                if (d->read((char *)data + h*bpl, bpl) != bpl)

                    break;

            }

        }

    }

    else if (nbits == 16 || nbits == 24 || nbits == 32) { // 16,24,32 bit BMP image

        register QRgb *p;

        QRgb  *end;

        uchar *buf24 = new uchar[bpl];

        int    bpl24 = ((w*nbits+31)/32)*4;

        uchar *b;

        int c;

        while (--h >= 0) {

            p = (QRgb *)(data + h*bpl);

            end = p + w;

            if (d->read((char *)buf24,bpl24) != bpl24)

                break;

            b = buf24;

            while (p < end) {

                c = *(uchar*)b | (*(uchar*)(b+1)<<8);

                if (nbits != 16)

                    c |= *(uchar*)(b+2)<<16;

                *p++ = qRgb(((c & red_mask) >> red_shift) * red_scale,

                                        ((c & green_mask) >> green_shift) * green_scale,

                                        ((c & blue_mask) >> blue_shift) * blue_scale);

                b += nbits/8;

            }

        }

        delete[] buf24;

    }

    if (bi.biHeight < 0) {

        // Flip the image

        uchar *buf = new uchar[bpl];

        h = -bi.biHeight;

        for (int y = 0; y < h/2; ++y) {

            memcpy(buf, data + y*bpl, bpl);

            memcpy(data + y*bpl, data + (h-y-1)*bpl, bpl);

            memcpy(data + (h-y-1)*bpl, buf, bpl);

        }

        delete [] buf;

    }

    return true;

}

// this is also used in qmime_win.cpp

bool qt_write_dib(QDataStream &s, QImage image)

{

    int        nbits;

    int        bpl_bmp;

    int        bpl = image.bytesPerLine();

    QIODevice* d = s.device();

    if (!d->isWritable())

        return false;