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/*! 

    \class QtIcoHandler

    \since 4.4

    \brief The QtIcoHandler class provides support for the ICO image format.

    \internal

*/

#include "qicohandler.h"

#include <QtCore/qendian.h>

#include <QtGui/QImage>

#include <QtCore/QFile>

#include <QtCore/QBuffer>

#include <qvariant.h>

// These next two structs represent how the icon information is stored

// in an ICO file.

typedef struct

{

    quint8  bWidth;               // Width of the image

    quint8  bHeight;              // Height of the image (times 2)

    quint8  bColorCount;          // Number of colors in image (0 if >=8bpp) [ not ture ]

    quint8  bReserved;            // Reserved

    quint16 wPlanes;              // Color Planes

    quint16 wBitCount;            // Bits per pixel

    quint32 dwBytesInRes;         // how many bytes in this resource?

    quint32 dwImageOffset;        // where in the file is this image

} ICONDIRENTRY, *LPICONDIRENTRY;

#define ICONDIRENTRY_SIZE 16

typedef struct

{

    quint16 idReserved;   // Reserved

    quint16 idType;       // resource type (1 for icons)

    quint16 idCount;      // how many images?

    ICONDIRENTRY    idEntries[1]; // the entries for each image

} ICONDIR, *LPICONDIR;

#define ICONDIR_SIZE    6       // Exclude the idEntries field

typedef struct {                    // BMP information header

    quint32 biSize;                // size of this struct

    quint32 biWidth;               // pixmap width

    quint32 biHeight;              // pixmap height     (specifies the combined height of the XOR and AND masks)

    quint16 biPlanes;              // should be 1

    quint16 biBitCount;            // number of bits per pixel

    quint32 biCompression;         // compression method

    quint32 biSizeImage;           // size of image

    quint32 biXPelsPerMeter;       // horizontal resolution

    quint32 biYPelsPerMeter;       // vertical resolution

    quint32 biClrUsed;             // number of colors used

    quint32 biClrImportant;        // number of important colors

} BMP_INFOHDR ,*LPBMP_INFOHDR;

#define BMP_INFOHDR_SIZE 40

class ICOReader

{

public:

    ICOReader(QIODevice * iodevice);

    int count();

    QImage iconAt(int index);

    static bool canRead(QIODevice *iodev);

    static QList<QImage> read(QIODevice * device);

    static bool write(QIODevice * device, const QList<QImage> & images);

private:

    bool readHeader();

    bool readIconEntry(int index, ICONDIRENTRY * iconEntry);

    bool readBMPHeader(quint32 imageOffset, BMP_INFOHDR * header);

    void findColorInfo(QImage & image);

    void readColorTable(QImage & image);

    void readBMP(QImage & image);

    void read1BitBMP(QImage & image);

    void read4BitBMP(QImage & image);

    void read8BitBMP(QImage & image);

    void read16_24_32BMP(QImage & image);

    struct IcoAttrib

    {

        int nbits;

        int ncolors;

        int h;

        int w;

        int depth;

    } icoAttrib;

    QIODevice * iod;

    qint64 startpos;

    bool headerRead;

    ICONDIR iconDir;

};

// Data readers and writers that takes care of alignment and endian stuff.

static bool readIconDirEntry(QIODevice *iodev, ICONDIRENTRY *iconDirEntry)

{

    if (iodev) {

        uchar tmp[ICONDIRENTRY_SIZE];

        if (iodev->read((char*)tmp, ICONDIRENTRY_SIZE) == ICONDIRENTRY_SIZE) {

            iconDirEntry->bWidth = tmp[0];

            iconDirEntry->bHeight = tmp[1];

            iconDirEntry->bColorCount = tmp[2];

            iconDirEntry->bReserved = tmp[3];

            iconDirEntry->wPlanes = qFromLittleEndian<quint16>(&tmp[4]);

            iconDirEntry->wBitCount = qFromLittleEndian<quint16>(&tmp[6]);

            iconDirEntry->dwBytesInRes = qFromLittleEndian<quint32>(&tmp[8]);

            iconDirEntry->dwImageOffset = qFromLittleEndian<quint32>(&tmp[12]);

            return true;

        }

    }

    return false;

}

static bool writeIconDirEntry(QIODevice *iodev, const ICONDIRENTRY &iconEntry)

{

    if (iodev) {

        uchar tmp[ICONDIRENTRY_SIZE];

        tmp[0] = iconEntry.bWidth;

        tmp[1] = iconEntry.bHeight;

        tmp[2] = iconEntry.bColorCount;

        tmp[3] = iconEntry.bReserved;

        qToLittleEndian<quint16>(iconEntry.wPlanes, &tmp[4]);

        qToLittleEndian<quint16>(iconEntry.wBitCount, &tmp[6]);

        qToLittleEndian<quint32>(iconEntry.dwBytesInRes, &tmp[8]);

        qToLittleEndian<quint32>(iconEntry.dwImageOffset, &tmp[12]);

        return (iodev->write((char*)tmp,  ICONDIRENTRY_SIZE) == ICONDIRENTRY_SIZE) ? true : false;

    }

    return false;

}

static bool readIconDir(QIODevice *iodev, ICONDIR *iconDir)

{

    if (iodev) {

        uchar tmp[ICONDIR_SIZE];

        if (iodev->read((char*)tmp, ICONDIR_SIZE) == ICONDIR_SIZE) {

            iconDir->idReserved = qFromLittleEndian<quint16>(&tmp[0]);

            iconDir->idType = qFromLittleEndian<quint16>(&tmp[2]);

            iconDir->idCount = qFromLittleEndian<quint16>(&tmp[4]);

            return true;

        }

    }

    return false;

}

static bool writeIconDir(QIODevice *iodev, const ICONDIR &iconDir)

{

    if (iodev) {

        uchar tmp[6];

        qToLittleEndian(iconDir.idReserved, tmp);

        qToLittleEndian(iconDir.idType, &tmp[2]);

        qToLittleEndian(iconDir.idCount, &tmp[4]);

        return (iodev->write((char*)tmp,  6) == 6) ? true : false;

    }

    return false;

}

static bool readBMPInfoHeader(QIODevice *iodev, BMP_INFOHDR *pHeader)

{

    if (iodev) {

        uchar header[BMP_INFOHDR_SIZE];

        if (iodev->read((char*)header, BMP_INFOHDR_SIZE) == BMP_INFOHDR_SIZE) {

            pHeader->biSize = qFromLittleEndian<quint32>(&header[0]);

            pHeader->biWidth = qFromLittleEndian<quint32>(&header[4]);

            pHeader->biHeight = qFromLittleEndian<quint32>(&header[8]);

            pHeader->biPlanes = qFromLittleEndian<quint16>(&header[12]);

            pHeader->biBitCount = qFromLittleEndian<quint16>(&header[14]);

            pHeader->biCompression = qFromLittleEndian<quint32>(&header[16]);

            pHeader->biSizeImage = qFromLittleEndian<quint32>(&header[20]);

            pHeader->biXPelsPerMeter = qFromLittleEndian<quint32>(&header[24]);

            pHeader->biYPelsPerMeter = qFromLittleEndian<quint32>(&header[28]);

            pHeader->biClrUsed = qFromLittleEndian<quint32>(&header[32]);

            pHeader->biClrImportant = qFromLittleEndian<quint32>(&header[36]);

            return true;

        }

    }

    return false;

}

static bool writeBMPInfoHeader(QIODevice *iodev, const BMP_INFOHDR &header)

{

    if (iodev) {

        uchar tmp[BMP_INFOHDR_SIZE];

        qToLittleEndian<quint32>(header.biSize, &tmp[0]);

        qToLittleEndian<quint32>(header.biWidth, &tmp[4]);

        qToLittleEndian<quint32>(header.biHeight, &tmp[8]);

        qToLittleEndian<quint16>(header.biPlanes, &tmp[12]);

        qToLittleEndian<quint16>(header.biBitCount, &tmp[14]);

        qToLittleEndian<quint32>(header.biCompression, &tmp[16]);

        qToLittleEndian<quint32>(header.biSizeImage, &tmp[20]);

        qToLittleEndian<quint32>(header.biXPelsPerMeter, &tmp[24]);

        qToLittleEndian<quint32>(header.biYPelsPerMeter, &tmp[28]);

        qToLittleEndian<quint32>(header.biClrUsed, &tmp[32]);

        qToLittleEndian<quint32>(header.biClrImportant, &tmp[36]);

        return (iodev->write((char*)tmp, BMP_INFOHDR_SIZE) == BMP_INFOHDR_SIZE) ? true : false;

    }

    return false;

}

ICOReader::ICOReader(QIODevice * iodevice)

: iod(iodevice)

, startpos(0)

, headerRead(false)

{

}

int ICOReader::count()

{

    if (readHeader())

        return iconDir.idCount;

    return 0;

}

bool ICOReader::canRead(QIODevice *iodev)

{

    bool isProbablyICO = false;

    if (iodev) {

        qint64 oldPos = iodev->pos();

        ICONDIR ikonDir;

        if (readIconDir(iodev, &ikonDir)) {

            qint64 readBytes = ICONDIR_SIZE;

            if (readIconDirEntry(iodev, &ikonDir.idEntries[0])) {

                readBytes += ICONDIRENTRY_SIZE;

                // ICO format does not have a magic identifier, so we read 6 different values, which will hopefully be enough to identify the file.

                if (   ikonDir.idReserved == 0

                    && ikonDir.idType == 1

                    && ikonDir.idEntries[0].bReserved == 0

                    && ikonDir.idEntries[0].wPlanes <= 1

                    && ikonDir.idEntries[0].wBitCount <= 32     // Bits per pixel

                    && ikonDir.idEntries[0].dwBytesInRes >= 40  // Must be over 40, since sizeof (infoheader) == 40

                    ) {

                    isProbablyICO = true;

                }

                if (iodev->isSequential()) {

                    // Our structs might be padded due to alignment, so we need to fetch each member before we ungetChar() !

                    quint32 tmp = ikonDir.idEntries[0].dwImageOffset;

                    iodev->ungetChar((tmp >> 24) & 0xff);

                    iodev->ungetChar((tmp >> 16) & 0xff);

                    iodev->ungetChar((tmp >>  8) & 0xff);

                    iodev->ungetChar(tmp & 0xff);

                    tmp = ikonDir.idEntries[0].dwBytesInRes;

                    iodev->ungetChar((tmp >> 24) & 0xff);

                    iodev->ungetChar((tmp >> 16) & 0xff);

                    iodev->ungetChar((tmp >>  8) & 0xff);

                    iodev->ungetChar(tmp & 0xff);

                    tmp = ikonDir.idEntries[0].wBitCount;

                    iodev->ungetChar((tmp >>  8) & 0xff);

                    iodev->ungetChar(tmp & 0xff);

                    tmp = ikonDir.idEntries[0].wPlanes;

                    iodev->ungetChar((tmp >>  8) & 0xff);

                    iodev->ungetChar(tmp & 0xff);

                    iodev->ungetChar(ikonDir.idEntries[0].bReserved);

                    iodev->ungetChar(ikonDir.idEntries[0].bColorCount);

                    iodev->ungetChar(ikonDir.idEntries[0].bHeight);

                    iodev->ungetChar(ikonDir.idEntries[0].bWidth);

                }

            }

            if (iodev->isSequential()) {

                // Our structs might be padded due to alignment, so we need to fetch each member before we ungetChar() !

                quint32 tmp = ikonDir.idCount;

                iodev->ungetChar((tmp >>  8) & 0xff);

                iodev->ungetChar(tmp & 0xff);

                tmp = ikonDir.idType;

                iodev->ungetChar((tmp >>  8) & 0xff);

                iodev->ungetChar(tmp & 0xff);

                tmp = ikonDir.idReserved;

                iodev->ungetChar((tmp >>  8) & 0xff);

                iodev->ungetChar(tmp & 0xff);

            }

        }

        if (!iodev->isSequential()) iodev->seek(oldPos);

    }

    return isProbablyICO;

}

bool ICOReader::readHeader()

{

    if (iod && !headerRead) {

        startpos = iod->pos();

        if (readIconDir(iod, &iconDir)) {

            if (iconDir.idReserved == 0 || iconDir.idType == 1)

            headerRead = true;

        }

    }

    return headerRead;

}

bool ICOReader::readIconEntry(int index, ICONDIRENTRY *iconEntry)

{

    if (iod) {

        if (iod->seek(startpos + ICONDIR_SIZE + (index * ICONDIRENTRY_SIZE))) {

            return readIconDirEntry(iod, iconEntry);

        }

    }

    return false;

}

bool ICOReader::readBMPHeader(quint32 imageOffset, BMP_INFOHDR * header)

{

    if (iod) {

        if (iod->seek(startpos + imageOffset)) {

            if (readBMPInfoHeader(iod, header)) {

                return TRUE;

            }

        }

    }

    return FALSE;

}

void ICOReader::findColorInfo(QImage & image)

{

    if (icoAttrib.ncolors > 0) {                // set color table

        readColorTable(image);

    } else if (icoAttrib.nbits == 16) { // don't support RGB values for 15/16 bpp

        image = QImage();

    }

}

void ICOReader::readColorTable(QImage & image)

{

    if (iod) {

        image.setColorCount(icoAttrib.ncolors);

        uchar rgb[4];

        for (int i=0; i<icoAttrib.ncolors; i++) {

            if (iod->read((char*)rgb, 4) != 4) {

            image = QImage();

            break;

            }

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

        }

    } else {

        image = QImage();

    }

}

void ICOReader::readBMP(QImage & image)

{

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

        read1BitBMP(image);

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

        read4BitBMP(image);

    } else if (icoAttrib.nbits == 8) {

        read8BitBMP(image);

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

        read16_24_32BMP(image);

    }

}

/**

 * NOTE: A 1 bit BMP is only flipped vertically, and not horizontally like all other color depths!

 * (This is the same with the bitmask)

 *

 */

void ICOReader::read1BitBMP(QImage & image)

{

    if (iod) {

        int h = image.height();

        int bpl = image.bytesPerLine();

        while (--h >= 0) {

            if (iod->read((char*)image.scanLine(h),bpl) != bpl) {

                image = QImage();

                break;

            }

        }

    } else {

        image = QImage();

    }

}

void ICOReader::read4BitBMP(QImage & image)

{

    if (iod) {

        int h = icoAttrib.h;

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

        uchar *buf = new uchar[buflen];

        Q_CHECK_PTR(buf);

        while (--h >= 0) {

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

                image = QImage();

                break;

            }

            register uchar *p = image.scanLine(h);

            uchar *b = buf;

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

                *p++ = *b >> 4;

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

            }

            if (icoAttrib.w & 1)                    // the last nibble

                *p = *b >> 4;

        }

        delete [] buf;

    } else {

        image = QImage();

    }

}

void ICOReader::read8BitBMP(QImage & image)

{

    if (iod) {

        int h = icoAttrib.h;

        int bpl = image.bytesPerLine();

        while (--h >= 0) {

            if (iod->read((char *)image.scanLine(h), bpl) != bpl) {

                image = QImage();

                break;

            }

        }

    } else {

        image = QImage();

    }

}

void ICOReader::read16_24_32BMP(QImage & image)

{

    if (iod) {

        int h = icoAttrib.h;

        register QRgb *p;

        QRgb  *end;

        uchar *buf = new uchar[image.bytesPerLine()];

        int    bpl = ((icoAttrib.w*icoAttrib.nbits+31)/32)*4;

        uchar *b;

        while (--h >= 0) {

            p = (QRgb *)image.scanLine(h);

            end = p + icoAttrib.w;

            if (iod->read((char *)buf, bpl) != bpl) {

                image = QImage();

                break;

            }

            b = buf;

            while (p < end) {

                if (icoAttrib.nbits == 24)

                    *p++ = qRgb(*(b+2), *(b+1), *b);

                else if (icoAttrib.nbits == 32)

                    *p++ = qRgba(*(b+2), *(b+1), *b, *(b+3));

                b += icoAttrib.nbits/8;

            }

        }

        delete[] buf;

    } else {

        image = QImage();

    }

}

QImage ICOReader::iconAt(int index)

{

    QImage img;

    if (count() > index) { // forces header to be read

        ICONDIRENTRY iconEntry;

        if (readIconEntry(index, &iconEntry)) {

            static const uchar pngMagicData[] = { 137, 80, 78, 71, 13, 10, 26, 10 };

            iod->seek(iconEntry.dwImageOffset);