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#include "private/qppmhandler_p.h"

#ifndef QT_NO_IMAGEFORMAT_PPM

#include <qimage.h>

#include <qvariant.h>

#include <qvector.h>

#include <ctype.h>

QT_BEGIN_NAMESPACE

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

  PBM/PGM/PPM (ASCII and RAW) image read/write functions

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

static int read_pbm_int(QIODevice *d)

{

    char c;

    int          val = -1;

    bool  digit;

    const int buflen = 100;

    char  buf[buflen];

    for (;;) {

        if (!d->getChar(&c))                // end of file

            break;

        digit = isdigit((uchar) c);

        if (val != -1) {

            if (digit) {

                val = 10*val + c - '0';

                continue;

            } else {

                if (c == '#')                        // comment

                    d->readLine(buf, buflen);

                break;

            }

        }

        if (digit)                                // first digit

            val = c - '0';

        else if (isspace((uchar) c))

            continue;

        else if (c == '#')

            (void)d->readLine(buf, buflen);

        else

            break;

    }

    return val;

}

static bool read_pbm_header(QIODevice *device, char& type, int& w, int& h, int& mcc)

{

    char buf[3];

    if (device->read(buf, 3) != 3)                        // read P[1-6]<white-space>

        return false;

    if (!(buf[0] == 'P' && isdigit((uchar) buf[1]) && isspace((uchar) buf[2])))

        return false;

    type = buf[1];

    if (type < '1' || type > '6')

        return false;

    w = read_pbm_int(device);                        // get image width

    h = read_pbm_int(device);                        // get image height

    if (type == '1' || type == '4')

        mcc = 1;                                  // ignore max color component

    else

        mcc = read_pbm_int(device);               // get max color component

    if (w <= 0 || w > 32767 || h <= 0 || h > 32767 || mcc <= 0)

        return false;                                        // weird P.M image

    return true;

}

static bool read_pbm_body(QIODevice *device, char type, int w, int h, int mcc, QImage *outImage)

{

    int nbits, y;

    int pbm_bpl;

    bool raw;

    QImage::Format format;

    switch (type) {

        case '1':                                // ascii PBM

        case '4':                                // raw PBM

            nbits = 1;

            format = QImage::Format_Mono;

            break;

        case '2':                                // ascii PGM

        case '5':                                // raw PGM

            nbits = 8;

            format = QImage::Format_Indexed8;

            break;

        case '3':                                // ascii PPM

        case '6':                                // raw PPM

            nbits = 32;

            format = QImage::Format_RGB32;

            break;

        default:

            return false;

    }

    raw = type >= '4';

    int maxc = mcc;

    if (maxc > 255)

        maxc = 255;

    if (outImage->size() != QSize(w, h) || outImage->format() != format) {

        *outImage = QImage(w, h, format);

        if (outImage->isNull())

            return false;

    }

    pbm_bpl = (nbits*w+7)/8;                        // bytes per scanline in PBM

    if (raw) {                                // read raw data

        if (nbits == 32) {                        // type 6

            pbm_bpl = mcc < 256 ? 3*w : 6*w;

            uchar *buf24 = new uchar[pbm_bpl], *b;

            QRgb  *p;

            QRgb  *end;

            for (y=0; y<h; y++) {

                if (device->read((char *)buf24, pbm_bpl) != pbm_bpl) {

                    delete[] buf24;

                    return false;

                }

                p = (QRgb *)outImage->scanLine(y);

                end = p + w;

                b = buf24;

                while (p < end) {

                    if (mcc < 256) {

                        *p++ = qRgb(b[0],b[1],b[2]);

                        b += 3;

                    } else {

                        *p++ = qRgb(((int(b[0]) * 256 + int(b[1]) + 1) * 256) / (mcc + 1) - 1,

                                    ((int(b[2]) * 256 + int(b[3]) + 1) * 256) / (mcc + 1) - 1,

                                    ((int(b[4]) * 256 + int(b[5]) + 1) * 256) / (mcc + 1) - 1);

                        b += 6;

                    }

                }

            }

            delete[] buf24;

        } else {                                // type 4,5

            for (y=0; y<h; y++) {

                if (device->read((char *)outImage->scanLine(y), pbm_bpl)

                        != pbm_bpl)

                    return false;

            }

        }

    } else {                                        // read ascii data

        register uchar *p;

        int n;

        for (y=0; y<h; y++) {

            p = outImage->scanLine(y);

            n = pbm_bpl;

            if (nbits == 1) {

                int b;

                int bitsLeft = w;

                while (n--) {

                    b = 0;

                    for (int i=0; i<8; i++) {

                        if (i < bitsLeft)

                            b = (b << 1) | (read_pbm_int(device) & 1);

                        else

                            b = (b << 1) | (0 & 1); // pad it our self if we need to

                    }

                    bitsLeft -= 8;

                    *p++ = b;

                }

            } else if (nbits == 8) {

                if (mcc == maxc) {

                    while (n--) {

                        *p++ = read_pbm_int(device);

                    }

                } else {

                    while (n--) {

                        *p++ = read_pbm_int(device) * maxc / mcc;

                    }

                }

            } else {                                // 32 bits

                n /= 4;

                int r, g, b;

                if (mcc == maxc) {

                    while (n--) {

                        r = read_pbm_int(device);

                        g = read_pbm_int(device);

                        b = read_pbm_int(device);

                        *((QRgb*)p) = qRgb(r, g, b);

                        p += 4;

                    }

                } else {

                    while (n--) {

                        r = read_pbm_int(device) * maxc / mcc;

                        g = read_pbm_int(device) * maxc / mcc;

                        b = read_pbm_int(device) * maxc / mcc;

                        *((QRgb*)p) = qRgb(r, g, b);

                        p += 4;

                    }

                }

            }

        }

    }

    if (nbits == 1) {                                // bitmap

        outImage->setColorCount(2);

        outImage->setColor(0, qRgb(255,255,255)); // white

        outImage->setColor(1, qRgb(0,0,0));        // black

    } else if (nbits == 8) {                        // graymap

        outImage->setColorCount(maxc+1);

        for (int i=0; i<=maxc; i++)

            outImage->setColor(i, qRgb(i*255/maxc,i*255/maxc,i*255/maxc));

    }

    return true;

}

static bool write_pbm_image(QIODevice *out, const QImage &sourceImage, const QByteArray &sourceFormat)

{

    QByteArray str;

    QImage image = sourceImage;

    QByteArray format = sourceFormat;

    format = format.left(3);                        // ignore RAW part

    bool gray = format == "pgm";

    if (format == "pbm") {

        image = image.convertToFormat(QImage::Format_Mono);

    } else if (image.depth() == 1) {

        image = image.convertToFormat(QImage::Format_Indexed8);

    } else {

        switch (image.format()) {

        case QImage::Format_RGB16:

        case QImage::Format_RGB666:

        case QImage::Format_RGB555:

        case QImage::Format_RGB888:

        case QImage::Format_RGB444:

            image = image.convertToFormat(QImage::Format_RGB32);

            break;

        case QImage::Format_ARGB8565_Premultiplied:

        case QImage::Format_ARGB6666_Premultiplied:

        case QImage::Format_ARGB8555_Premultiplied:

        case QImage::Format_ARGB4444_Premultiplied:

            image = image.convertToFormat(QImage::Format_ARGB32);

            break;

        default:

            break;

        }

    }

    if (image.depth() == 1 && image.colorCount() == 2) {

        if (qGray(image.color(0)) < qGray(image.color(1))) {

            // 0=dark/black, 1=light/white - invert

            image.detach();

            for (int y=0; y<image.height(); y++) {

                uchar *p = image.scanLine(y);

                uchar *end = p + image.bytesPerLine();

                while (p < end)

                    *p++ ^= 0xff;

            }

        }

    }

    uint w = image.width();

    uint h = image.height();

    str = "P\n";

    str += QByteArray::number(w);

    str += ' ';

    str += QByteArray::number(h);

    str += '\n';

    switch (image.depth()) {

        case 1: {

            str.insert(1, '4');

            if (out->write(str, str.length()) != str.length())

                return false;

            w = (w+7)/8;

            for (uint y=0; y<h; y++) {

                uchar* line = image.scanLine(y);

                if (w != (uint)out->write((char*)line, w))

                    return false;

            }

            }

            break;

        case 8: {

            str.insert(1, gray ? '5' : '6');

            str.append("255\n");

            if (out->write(str, str.length()) != str.length())

                return false;

            QVector<QRgb> color = image.colorTable();

            uint bpl = w*(gray ? 1 : 3);

            uchar *buf   = new uchar[bpl];

            for (uint y=0; y<h; y++) {

                uchar *b = image.scanLine(y);

                uchar *p = buf;

                uchar *end = buf+bpl;

                if (gray) {

                    while (p < end) {

                        uchar g = (uchar)qGray(color[*b++]);

                        *p++ = g;

                    }

                } else {

                    while (p < end) {

                        QRgb rgb = color[*b++];

                        *p++ = qRed(rgb);

                        *p++ = qGreen(rgb);

                        *p++ = qBlue(rgb);

                    }

                }

                if (bpl != (uint)out->write((char*)buf, bpl))

                    return false;

            }

            delete [] buf;

            }

            break;

        case 32: {

            str.insert(1, gray ? '5' : '6');

            str.append("255\n");

            if (out->write(str, str.length()) != str.length())

                return false;

            uint bpl = w*(gray ? 1 : 3);

            uchar *buf = new uchar[bpl];

            for (uint y=0; y<h; y++) {

                QRgb  *b = (QRgb*)image.scanLine(y);

                uchar *p = buf;

                uchar *end = buf+bpl;

                if (gray) {

                    while (p < end) {

                        uchar g = (uchar)qGray(*b++);

                        *p++ = g;

                    }

                } else {

                    while (p < end) {

                        QRgb rgb = *b++;

                        *p++ = qRed(rgb);

                        *p++ = qGreen(rgb);

                        *p++ = qBlue(rgb);

                    }

                }

                if (bpl != (uint)out->write((char*)buf, bpl))

                    return false;

            }

            delete [] buf;

            }

            break;

    default:

        return false;

    }

    return true;

}

QPpmHandler::QPpmHandler()

    : state(Ready)

{

}

bool QPpmHandler::readHeader()

{

    state = Error;

    if (!read_pbm_header(device(), type, width, height, mcc))

        return false;

    state = ReadHeader;

    return true;

}

bool QPpmHandler::canRead() const

{

    if (state == Ready) {

        if (!canRead(device(), &subType))

            return false;

        setFormat(subType);

        return true;

    }

    return state != Error;

}

bool QPpmHandler::canRead(QIODevice *device, QByteArray *subType)

{

    if (!device) {

        qWarning("QPpmHandler::canRead() called with no device");

        return false;

    }

    char head[2];

    if (device->peek(head, sizeof(head)) != sizeof(head))

        return false;

    if (head[0] != 'P')

        return false;

    if (head[1] == '1' || head[1] == '4') {

        if (subType)

            *subType = "pbm";

    } else if (head[1] == '2' || head[1] == '5') {

        if (subType)

            *subType = "pgm";

    } else if (head[1] == '3' || head[1] == '6') {

        if (subType)

            *subType = "ppm";

    } else {

        return false;

    }

    return true;

}

bool QPpmHandler::read(QImage *image)

{

    if (state == Error)

        return false;

    if (state == Ready && !readHeader()) {

        state = Error;

        return false;

    }

    if (!read_pbm_body(device(), type, width, height, mcc, image)) {

        state = Error;

        return false;

    }

    state = Ready;

    return true;

}

bool QPpmHandler::write(const QImage &image)

{

    return write_pbm_image(device(), image, subType);

}

bool QPpmHandler::supportsOption(ImageOption option) const

{

    return option == SubType

        || option == Size

        || option == ImageFormat;

}

QVariant QPpmHandler::option(ImageOption option) const

{

    if (option == SubType) {

        return subType;

    } else if (option == Size) {

        if (state == Error)

            return QVariant();

        if (state == Ready && !const_cast<QPpmHandler*>(this)->readHeader())

            return QVariant();

        return QSize(width, height);

    } else if (option == ImageFormat) {

        if (state == Error)

            return QVariant();

        if (state == Ready && !const_cast<QPpmHandler*>(this)->readHeader())

            return QVariant();

        QImage::Format format = QImage::Format_Invalid;

        switch (type) {

            case '1':                                // ascii PBM

            case '4':                                // raw PBM

            format = QImage::Format_Mono;

            break;

            case '2':                                // ascii PGM

            case '5':                                // raw PGM

                format = QImage::Format_Indexed8;

                break;

            case '3':                                // ascii PPM

            case '6':                                // raw PPM

                format = QImage::Format_RGB32;

                break;

            default:

                break;

        }

        return format;

    }

    return QVariant();

}

void QPpmHandler::setOption(ImageOption option, const QVariant &value)

{

    if (option == SubType)

        subType = value.toByteArray().toLower();

}

QByteArray QPpmHandler::name() const

{

    return subType.isEmpty() ? QByteArray("ppm") : subType;

}