File indexing completed on 2024-04-28 03:54:44

 /*
     Photoshop File Format support for QImage.
 
     SPDX-FileCopyrightText: 2003 Ignacio Castaño <castano@ludicon.com>
     SPDX-FileCopyrightText: 2015 Alex Merry <alex.merry@kde.org>
     SPDX-FileCopyrightText: 2022-2023 Mirco Miranda <mircomir@outlook.com>
 
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
 /*
  * The early version of this code was based on Thacher Ulrich PSD loading code
  * released into the public domain. See: http://tulrich.com/geekstuff/
  */
 
 /*
  * Documentation on this file format is available at
  * http://www.adobe.com/devnet-apps/photoshop/fileformatashtml/
  */
 
 /*
  * Limitations of the current code:
  * - Color spaces other than RGB/Grayscale cannot be read due to lack of QImage
  *   support. Where possible, a conversion to RGB is done:
  *   - CMYK images are converted using an approximated way that ignores the color
  *     information (ICC profile).
  *   - LAB images are converted to sRGB using literature formulas.
  *   - MULICHANNEL images more than 3 channels are converted as CMYK images.
  *   - DUOTONE images are considered as Grayscale images.
  *
  *   NOTE: The best way to convert between different color spaces is to use a
  *   color management engine (e.g. LittleCMS).
  */
 
 #include "fastmath_p.h"
 #include "psd_p.h"
 #include "util_p.h"
 
 #include <QDataStream>
 #include <QDebug>
 #include <QImage>
 #include <QColorSpace>
 
 #include <cmath>
 #include <cstring>
 
 typedef quint32 uint;
 typedef quint16 ushort;
 typedef quint8 uchar;
 
 /* The fast LAB conversion converts the image to linear sRgb instead to sRgb.
  * This should not be a problem because the Qt's QColorSpace supports the linear
  * sRgb colorspace.
  *
  * Using linear conversion, the loading speed is slightly improved. Anyway, if you are using
  * an software that discard color info, you should comment it.
  *
  * At the time I'm writing (07/2022), Gwenview and Krita supports linear sRgb but KDE
  * preview creator does not. This is the why, for now, it is disabled.
  */
 //#define PSD_FAST_LAB_CONVERSION
 
 namespace // Private.
 {
 
 enum Signature : quint32 {
     S_8BIM = 0x3842494D, // '8BIM'
     S_8B64 = 0x38423634, // '8B64'
 
     S_MeSa = 0x4D655361   // 'MeSa'
 };
 
 enum ColorMode : quint16 {
     CM_BITMAP = 0,
     CM_GRAYSCALE = 1,
     CM_INDEXED = 2,
     CM_RGB = 3,
     CM_CMYK = 4,
     CM_MULTICHANNEL = 7,
     CM_DUOTONE = 8,
     CM_LABCOLOR = 9,
 };
 
 enum ImageResourceId : quint16 {
     IRI_RESOLUTIONINFO = 0x03ED,
     IRI_ICCPROFILE = 0x040F,
     IRI_TRANSPARENCYINDEX = 0x0417,
     IRI_VERSIONINFO = 0x0421,
     IRI_XMPMETADATA = 0x0424
 };
 
 enum LayerId : quint32 {
     LI_MT16 = 0x4D743136,   // 'Mt16',
     LI_MT32 = 0x4D743332,   // 'Mt32',
     LI_MTRN = 0x4D74726E    // 'Mtrn'
 };
 
 struct PSDHeader {
     uint signature;
     ushort version;
     uchar reserved[6];
     ushort channel_count;
     uint height;
     uint width;
     ushort depth;
     ushort color_mode;
 };
 
 struct PSDImageResourceBlock {
     QString name;
     QByteArray data;
 };
 
 /*!
  * \brief The PSDDuotoneOptions struct
  * \note You can decode the duotone data using the "Duotone Options"
  * file format found in the "Photoshop File Format" specs.
  */
 struct PSDDuotoneOptions {
     QByteArray data;
 };
 
 /*!
  * \brief The PSDColorModeDataSection struct
  * Only indexed color and duotone have color mode data.
  */
 struct PSDColorModeDataSection {
     PSDDuotoneOptions duotone;
     QList<QRgb> palette;
 };
 
 using PSDImageResourceSection = QHash<quint16, PSDImageResourceBlock>;
 
 struct PSDLayerInfo {
     qint64 size = -1;
     qint16 layerCount = 0;
 };
 
 struct PSDGlobalLayerMaskInfo {
     qint64 size = -1;
 };
 
 struct PSDAdditionalLayerInfo {
     Signature signature = Signature();
     LayerId id = LayerId();
     qint64 size = -1;
 };
 
 struct PSDLayerAndMaskSection {
     qint64 size = -1;
     PSDLayerInfo layerInfo;
     PSDGlobalLayerMaskInfo globalLayerMaskInfo;
     QHash<LayerId, PSDAdditionalLayerInfo> additionalLayerInfo;
 
     bool isNull() const {
         return (size <= 0);
     }
 
     bool hasAlpha() const {
         return layerInfo.layerCount < 0 ||
                additionalLayerInfo.contains(LI_MT16) ||
                additionalLayerInfo.contains(LI_MT32) ||
                additionalLayerInfo.contains(LI_MTRN);
     }
 
     bool atEnd(bool isPsb) const {
         qint64 currentSize = 0;
         if (layerInfo.size > -1) {
             currentSize += layerInfo.size + 4;
             if (isPsb)
                 currentSize += 4;
         }
         if (globalLayerMaskInfo.size > -1) {
             currentSize += globalLayerMaskInfo.size + 4;
         }
         auto aliv = additionalLayerInfo.values();
         for (auto &&v : aliv) {
             currentSize += (12 + v.size);
             if (v.signature == S_8B64)
                 currentSize += 4;
         }
         return (size <= currentSize);
     }
 };
 
 /*!
  * \brief fixedPointToDouble
  * Converts a fixed point number to floating point one.
  */
 static double fixedPointToDouble(qint32 fixedPoint)
 {
     auto i = double(fixedPoint >> 16);
     auto d = double((fixedPoint & 0x0000FFFF) / 65536.0);
     return (i+d);
 }
 
 static qint64 readSize(QDataStream &s, bool psb = false)
 {
     qint64 size = 0;
     if (!psb) {
         quint32 tmp;
         s >> tmp;
         size = tmp;
     }
     else {
         s >> size;
     }
     if (s.status() != QDataStream::Ok) {
         size = -1;
     }
     return size;
 }
 
 static bool skip_data(QDataStream &s, qint64 size)
 {
     // Skip mode data.
     for (qint32 i32 = 0; size; size -= i32) {
         i32 = std::min(size, qint64(std::numeric_limits<qint32>::max()));
         i32 = s.skipRawData(i32);
         if (i32 < 1)
             return false;
     }
     return true;
 }
 
 static bool skip_section(QDataStream &s, bool psb = false)
 {
     auto section_length = readSize(s, psb);
     if (section_length < 0)
         return false;
     return skip_data(s, section_length);
 }
 
 /*!
  * \brief readPascalString
  * Reads the Pascal string as defined in the PSD specification.
  * \param s The stream.
  * \param alignBytes Alignment of the string.
  * \param size Number of stream bytes used.
  * \return The string read.
  */
 static QString readPascalString(QDataStream &s, qint32 alignBytes = 1, qint32 *size = nullptr)
 {
     qint32 tmp = 0;
     if (size == nullptr)
         size = &tmp;
 
     quint8 stringSize;
     s >> stringSize;
     *size = sizeof(stringSize);
 
     QString str;
     if (stringSize > 0) {
         QByteArray ba;
         ba.resize(stringSize);
         auto read = s.readRawData(ba.data(), ba.size());
         if (read > 0) {
             *size += read;
             str = QString::fromLatin1(ba);
         }
     }
 
     // align
     if (alignBytes > 1)
         if (auto pad = *size % alignBytes)
             *size += s.skipRawData(alignBytes - pad);
 
     return str;
 }
 
 /*!
  * \brief readImageResourceSection
  * Reads the image resource section.
  * \param s The stream.
  * \param ok Pointer to the operation result variable.
  * \return The image resource section raw data.
  */
 static PSDImageResourceSection readImageResourceSection(QDataStream &s, bool *ok = nullptr)
 {
     PSDImageResourceSection irs;
 
     bool tmp = true;
     if (ok == nullptr)
         ok = &tmp;
     *ok = true;
 
     // Section size
     qint32 sectioSize;
     s >> sectioSize;
 
     // Reading Image resource block
     for (auto size = sectioSize; size > 0;) {
         // Length      Description
         // -------------------------------------------------------------------
         // 4           Signature: '8BIM'
         // 2           Unique identifier for the resource. Image resource IDs
         //             contains a list of resource IDs used by Photoshop.
         // Variable    Name: Pascal string, padded to make the size even
         //             (a null name consists of two bytes of 0)
         // 4           Actual size of resource data that follows
         // Variable    The resource data, described in the sections on the
         //             individual resource types. It is padded to make the size
         //             even.
 
         quint32 signature;
         s >> signature;
         size -= sizeof(signature);
         // NOTE: MeSa signature is not documented but found in some old PSD take from Photoshop 7.0 CD.
         if (signature != S_8BIM && signature != S_MeSa) { // 8BIM and MeSa
             qDebug() << "Invalid Image Resource Block Signature!";
             *ok = false;
             break;
         }
 
         // id
         quint16 id;
         s >> id;
         size -= sizeof(id);
 
         // getting data
         PSDImageResourceBlock irb;
 
         // name
         qint32 bytes = 0;
         irb.name = readPascalString(s, 2, &bytes);
         size -= bytes;
 
         // data read
         quint32 dataSize;
         s >> dataSize;
         size -= sizeof(dataSize);
         // NOTE: Qt device::read() and QDataStream::readRawData() could read less data than specified.
         //       The read code should be improved.
         if (auto dev = s.device())
             irb.data = dev->read(dataSize);
         auto read = irb.data.size();
         if (read > 0)
             size -= read;
         if (quint32(read) != dataSize) {
             qDebug() << "Image Resource Block Read Error!";
             *ok = false;
             break;
         }
 
         if (auto pad = dataSize % 2) {
             auto skipped = s.skipRawData(pad);
             if (skipped > 0)
                 size -= skipped;
         }
 
         // insert IRB
         irs.insert(id, irb);
     }
 
     return irs;
 }
 
 PSDAdditionalLayerInfo readAdditionalLayer(QDataStream &s, bool *ok = nullptr)
 {
     PSDAdditionalLayerInfo li;
 
     bool tmp = true;
     if (ok == nullptr)
         ok = &tmp;
 
     s >> li.signature;
     *ok = li.signature == S_8BIM || li.signature == S_8B64;
     if (!*ok)
         return li;
 
     s >> li.id;
     *ok = s.status() == QDataStream::Ok;
     if (!*ok)
         return li;
 
     li.size = readSize(s, li.signature == S_8B64);
     *ok = li.size >= 0;
     if (!*ok)
         return li;
 
     *ok = skip_data(s, li.size);
 
     return li;
 }
 
 PSDLayerAndMaskSection readLayerAndMaskSection(QDataStream &s, bool isPsb, bool *ok = nullptr)
 {
     PSDLayerAndMaskSection lms;
 
     bool tmp = true;
     if (ok == nullptr)
         ok = &tmp;
     *ok = true;
 
     auto device = s.device();
     device->startTransaction();
 
     lms.size = readSize(s, isPsb);
 
     // read layer info
     if (s.status() == QDataStream::Ok && !lms.atEnd(isPsb)) {
         lms.layerInfo.size = readSize(s, isPsb);
         if (lms.layerInfo.size > 0) {
             s >> lms.layerInfo.layerCount;
             skip_data(s, lms.layerInfo.size - sizeof(lms.layerInfo.layerCount));
         }
     }
 
     // read global layer mask info
     if (s.status() == QDataStream::Ok && !lms.atEnd(isPsb)) {
         lms.globalLayerMaskInfo.size = readSize(s, false); // always 32-bits
         if (lms.globalLayerMaskInfo.size > 0) {
             skip_data(s, lms.globalLayerMaskInfo.size);
         }
     }
 
     // read additional layer info
     if (s.status() == QDataStream::Ok) {
         for (bool ok = true; ok && !lms.atEnd(isPsb);) {
             auto al = readAdditionalLayer(s, &ok);
             if (ok)
                 lms.additionalLayerInfo.insert(al.id, al);
         }
     }
 
     device->rollbackTransaction();
     *ok = skip_section(s, isPsb);
     return lms;
 }
 
 /*!
  * \brief readColorModeDataSection
  * Read the color mode section
  * \param s The stream.
  * \param ok Pointer to the operation result variable.
  * \return The color mode section.
  */
 PSDColorModeDataSection readColorModeDataSection(QDataStream &s, bool *ok = nullptr)
 {
     PSDColorModeDataSection cms;
 
     bool tmp = false;
     if (ok == nullptr)
         ok = &tmp;
     *ok = true;
 
     qint32 size;
     s >> size;
     if (size != 768) {  // read the duotone data (524 bytes)
         // NOTE: A RGB/Gray float image has a 112 bytes ColorModeData that could be
         //       the "32-bit Toning Options" of Photoshop (starts with 'hdrt').
         //       Official Adobe specification tells "Only indexed color and duotone
         //       (see the mode field in the File header section) have color mode data.".
         //       See test case images 32bit_grayscale.psd and 32bit-rgb.psd
         cms.duotone.data = s.device()->read(size);
         if (cms.duotone.data.size() != size)
             *ok = false;
     }
     else {              // read the palette (768 bytes)
         auto&& palette = cms.palette;
         QList<quint8> vect(size);
         for (auto&& v : vect)
             s >> v;
         for (qsizetype i = 0, n = vect.size()/3; i < n; ++i)
             palette.append(qRgb(vect.at(i), vect.at(n+i), vect.at(n+n+i)));
     }
 
     return cms;
 }
 
 /*!
  * \brief setColorSpace
  * Set the color space to the image.
  * \param img The image.
  * \param irs The image resource section.
  * \return True on success, otherwise false.
  */
 static bool setColorSpace(QImage& img, const PSDImageResourceSection& irs)
 {
     if (!irs.contains(IRI_ICCPROFILE))
         return false;
     auto irb = irs.value(IRI_ICCPROFILE);
     auto cs = QColorSpace::fromIccProfile(irb.data);
     if (!cs.isValid())
         return false;
     img.setColorSpace(cs);
     return true;
 }
 
 /*!
  * \brief setXmpData
  * Adds XMP metadata to QImage.
  * \param img The image.
  * \param irs The image resource section.
  * \return True on success, otherwise false.
  */
 static bool setXmpData(QImage& img, const PSDImageResourceSection& irs)
 {
     if (!irs.contains(IRI_XMPMETADATA))
         return false;
     auto irb = irs.value(IRI_XMPMETADATA);
     auto xmp = QString::fromUtf8(irb.data);
     if (xmp.isEmpty())
         return false;
     // NOTE: "XML:com.adobe.xmp" is the meta set by Qt reader when an
     //       XMP packet is found (e.g. when reading a PNG saved by Photoshop).
     //       I'm reusing the same key because a programs could search for it.
     img.setText(QStringLiteral("XML:com.adobe.xmp"), xmp);
     return true;
 }
 
 /*!
  * \brief hasMergedData
  * Checks if merged image data are available.
  * \param irs The image resource section.
  * \return True on success or if the block does not exist, otherwise false.
  */
 static bool hasMergedData(const PSDImageResourceSection& irs)
 {
     if (!irs.contains(IRI_VERSIONINFO))
         return true;
     auto irb = irs.value(IRI_VERSIONINFO);
     if (irb.data.size() > 4)
         return irb.data.at(4) != 0;
     return false;
 }
 
 /*!
  * \brief setResolution
  * Set the image resolution.
  * \param img The image.
  * \param irs The image resource section.
  * \return True on success, otherwise false.
  */
 static bool setResolution(QImage& img, const PSDImageResourceSection& irs)
 {
     if (!irs.contains(IRI_RESOLUTIONINFO))
         return false;
     auto irb = irs.value(IRI_RESOLUTIONINFO);
 
     QDataStream s(irb.data);
     s.setByteOrder(QDataStream::BigEndian);
 
     qint32 i32;
     s >> i32;                               // Horizontal resolution in pixels per inch.
     if (i32 <= 0)
         return false;
     auto hres = fixedPointToDouble(i32);
 
     s.skipRawData(4);                       // Display data (not used here)
 
     s >> i32;                               // Vertial resolution in pixels per inch.
     if (i32 <= 0)
         return false;
     auto vres = fixedPointToDouble(i32);
 
     img.setDotsPerMeterX(hres * 1000 / 25.4);
     img.setDotsPerMeterY(vres * 1000 / 25.4);
     return true;
 }
 
 /*!
  * \brief setTransparencyIndex
  * Search for transparency index block and, if found, changes the alpha of the value at the given index.
  * \param img The image.
  * \param irs The image resource section.
  * \return True on success, otherwise false.
  */
 static bool setTransparencyIndex(QImage& img, const PSDImageResourceSection& irs)
 {
     if (!irs.contains(IRI_TRANSPARENCYINDEX))
         return false;
     auto irb = irs.value(IRI_TRANSPARENCYINDEX);
     QDataStream s(irb.data);
     s.setByteOrder(QDataStream::BigEndian);
     quint16 idx;
     s >> idx;
 
     auto palette = img.colorTable();
     if (idx < palette.size()) {
         auto&& v = palette[idx];
         v = QRgb(v & ~0xFF000000);
         img.setColorTable(palette);
         return true;
     }
 
     return false;
 }
 
 static QDataStream &operator>>(QDataStream &s, PSDHeader &header)
 {
     s >> header.signature;
     s >> header.version;
     for (int i = 0; i < 6; i++) {
         s >> header.reserved[i];
     }
     s >> header.channel_count;
     s >> header.height;
     s >> header.width;
     s >> header.depth;
     s >> header.color_mode;
     return s;
 }
 
 // Check that the header is a valid PSD (as written in the PSD specification).
 static bool IsValid(const PSDHeader &header)
 {
     if (header.signature != 0x38425053) { // '8BPS'
         //qDebug() << "PSD header: invalid signature" << header.signature;
         return false;
     }
     if (header.version != 1 && header.version != 2) {
         qDebug() << "PSD header: invalid version" << header.version;
         return false;
     }
     if (header.depth != 8 &&
         header.depth != 16 &&
         header.depth != 32 &&
         header.depth != 1) {
         qDebug() << "PSD header: invalid depth" << header.depth;
         return false;
     }
     if (header.color_mode != CM_RGB &&
         header.color_mode != CM_GRAYSCALE &&
         header.color_mode != CM_INDEXED &&
         header.color_mode != CM_DUOTONE &&
         header.color_mode != CM_CMYK &&
         header.color_mode != CM_LABCOLOR &&
         header.color_mode != CM_MULTICHANNEL &&
         header.color_mode != CM_BITMAP) {
         qDebug() << "PSD header: invalid color mode" << header.color_mode;
         return false;
     }
     // Specs tells: "Supported range is 1 to 56" but when the alpha channel is present the limit is 57:
     // Photoshop does not make you add more (see also 53alphas.psd test case).
     if (header.channel_count < 1 || header.channel_count > 57) {
         qDebug() << "PSD header: invalid number of channels" << header.channel_count;
         return false;
     }
     if (header.width > 300000 || header.height > 300000) {
         qDebug() << "PSD header: invalid image size" << header.width << "x" << header.height;
         return false;
     }
     return true;
 }
 
 // Check that the header is supported by this plugin.
 static bool IsSupported(const PSDHeader &header)
 {
     if (!IsValid(header)) {
         return false;
     }
     if (header.version != 1 && header.version != 2) {
         return false;
     }
     if (header.depth != 8 &&
         header.depth != 16 &&
         header.depth != 32 &&
         header.depth != 1) {
         return false;
     }
     if (header.color_mode != CM_RGB &&
         header.color_mode != CM_GRAYSCALE &&
         header.color_mode != CM_INDEXED &&
         header.color_mode != CM_DUOTONE &&
         header.color_mode != CM_CMYK &&
         header.color_mode != CM_MULTICHANNEL &&
         header.color_mode != CM_LABCOLOR &&
         header.color_mode != CM_BITMAP) {
         return false;
     }
     if (header.color_mode == CM_MULTICHANNEL &&
         header.channel_count < 3) {
         return false;
     }
     return true;
 }
 
 /*!
  * \brief decompress
  * Fast PackBits decompression.
  * \param input The compressed input buffer.
  * \param ilen The input buffer size.
  * \param output The uncompressed target buffer.
  * \param olen The target buffer size.
  * \return The number of valid bytes in the target buffer.
  */
 qint64 decompress(const char *input, qint64 ilen, char *output, qint64 olen)
 {
     qint64  j = 0;
     for (qint64 ip = 0, rr = 0, available = olen; j < olen && ip < ilen; available = olen - j) {
         signed char n = static_cast<signed char>(input[ip++]);
         if (n == -128)
             continue;
 
         if (n >= 0) {
             rr = qint64(n) + 1;
             if (available < rr) {
                 --ip;
                 break;
             }
 
             if (ip + rr > ilen)
                 return -1;
             memcpy(output + j, input + ip, size_t(rr));
             ip += rr;
         }
         else if (ip < ilen) {
             rr = qint64(1-n);
             if (available < rr) {
                 --ip;
                 break;
             }
             memset(output + j, input[ip++], size_t(rr));
         }
 
         j += rr;
     }
     return j;
 }
 
 /*!
  * \brief imageFormat
  * \param header The PSD header.
  * \return The Qt image format.
  */
 static QImage::Format imageFormat(const PSDHeader &header, bool alpha)
 {
     if (header.channel_count == 0) {
         return QImage::Format_Invalid;
     }
 
     auto format = QImage::Format_Invalid;
     switch(header.color_mode) {
     case CM_RGB:
         if (header.depth == 32)
             format = header.channel_count < 4 || !alpha ? QImage::Format_RGBX32FPx4 : QImage::Format_RGBA32FPx4_Premultiplied;
         else if (header.depth == 16)
             format = header.channel_count < 4 || !alpha ? QImage::Format_RGBX64 : QImage::Format_RGBA64_Premultiplied;
         else
             format = header.channel_count < 4 || !alpha ? QImage::Format_RGB888 : QImage::Format_RGBA8888_Premultiplied;
         break;
     case CM_MULTICHANNEL:       // Treat MCH as CMYK (number of channel check is done in IsSupported())
     case CM_CMYK:               // Photoshop supports CMYK/MCH 8-bits and 16-bits only
         if (header.depth == 16)
             format = header.channel_count < 5 || !alpha ? QImage::Format_RGBX64 : QImage::Format_RGBA64;
         else if (header.depth == 8)
             format = header.channel_count < 5 || !alpha ? QImage::Format_RGB888 : QImage::Format_RGBA8888;
         break;
     case CM_LABCOLOR:           // Photoshop supports LAB 8-bits and 16-bits only
         if (header.depth == 16)
             format = header.channel_count < 4 || !alpha ? QImage::Format_RGBX64 : QImage::Format_RGBA64;
         else if (header.depth == 8)
             format = header.channel_count < 4 || !alpha ? QImage::Format_RGB888 : QImage::Format_RGBA8888;
         break;
     case CM_GRAYSCALE:
     case CM_DUOTONE:
         format = header.depth == 8 ? QImage::Format_Grayscale8 : QImage::Format_Grayscale16;
         break;
     case CM_INDEXED:
         format = header.depth == 8 ? QImage::Format_Indexed8 : QImage::Format_Invalid;
         break;
     case CM_BITMAP:
         format = header.depth == 1 ? QImage::Format_Mono : QImage::Format_Invalid;
         break;
     }
     return format;
 }
 
 /*!
  * \brief imageChannels
  * \param format The Qt image format.
  * \return The number of channels of the image format.
  */
 static qint32 imageChannels(const QImage::Format& format)
 {
     qint32 c = 4;
     switch(format) {
     case QImage::Format_RGB888:
         c = 3;
         break;
     case QImage::Format_Grayscale8:
     case QImage::Format_Grayscale16:
     case QImage::Format_Indexed8:
     case QImage::Format_Mono:
         c = 1;
         break;
     default:
         break;
     }
     return c;
 }
 
 inline quint8 xchg(quint8 v)
 {
     return v;
 }
 
 inline quint16 xchg(quint16 v)
 {
 #if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
     return quint16( (v>>8) | (v<<8) );
 #else
     return v;   // never tested
 #endif
 }
 
 inline quint32 xchg(quint32 v)
 {
 #if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
     return quint32( (v>>24) | ((v & 0x00FF0000)>>8) | ((v & 0x0000FF00)<<8) | (v<<24) );
 #else
     return v;  // never tested
 #endif
 }
 
 inline float xchg(float v)
 {
 #if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
 #   ifdef Q_CC_MSVC
     float *pf = &v;
     quint32 f = xchg(*reinterpret_cast<quint32*>(pf));
     quint32 *pi = &f;
     return *reinterpret_cast<float*>(pi);
 #   else
     quint32 t;
     std::memcpy(&t, &v, sizeof(quint32));
     t = xchg(t);
     std::memcpy(&v, &t, sizeof(quint32));
     return v;
 #   endif
 #else
     return v;  // never tested
 #endif
 }
 
 template<class T>
 inline void planarToChunchy(uchar *target, const char *source, qint32 width, qint32 c, qint32 cn)
 {
     auto s = reinterpret_cast<const T*>(source);
     auto t = reinterpret_cast<T*>(target);
     for (qint32 x = 0; x < width; ++x) {
         t[x * cn + c] = xchg(s[x]);
     }
 }
 
 template<class T>
 inline void planarToChunchyFloatToUInt16(uchar *target, const char *source, qint32 width, qint32 c, qint32 cn)
 {
     auto s = reinterpret_cast<const T*>(source);
     auto t = reinterpret_cast<quint16*>(target);
     for (qint32 x = 0; x < width; ++x) {
         t[x * cn + c] = quint16(std::min(xchg(s[x]) * std::numeric_limits<quint16>::max() + 0.5, double(std::numeric_limits<quint16>::max())));
     }
 }
 
 enum class PremulConversion {
     PS2P, // Photoshop premul to qimage premul (required by RGB)
     PS2A, // Photoshop premul to unassociated alpha (required by RGB, CMYK and L* components of LAB)
     PSLab2A // Photoshop premul to unassociated alpha (required by a* and b* components of LAB)
 };
 
 template<class T>
 inline void premulConversion(char *stride, qint32 width, qint32 ac, qint32 cn, const PremulConversion &conv)
 {
     auto s = reinterpret_cast<T*>(stride);
     // NOTE: to avoid overflows, max is casted to qint64: that is possible because max is always an integer (even if T is float)
     auto max = qint64(std::numeric_limits<T>::is_integer ? std::numeric_limits<T>::max() : 1);
 
     for (qint32 c = 0; c < ac; ++c) {
         if (conv == PremulConversion::PS2P) {
             for (qint32 x = 0; x < width; ++x) {
                 auto xcn = x * cn;
                 auto alpha = *(s + xcn + ac);
                 *(s + xcn + c) = *(s + xcn + c) + alpha - max;
             }
         }
         else if (conv == PremulConversion::PS2A || (conv == PremulConversion::PSLab2A && c == 0)) {
             for (qint32 x = 0; x < width; ++x) {
                 auto xcn = x * cn;
                 auto alpha = *(s + xcn + ac);
                 if (alpha > 0)
                     *(s + xcn + c) = ((*(s + xcn + c) + alpha - max) * max + alpha / 2) / alpha;
             }
         }
         else if (conv == PremulConversion::PSLab2A) {
             for (qint32 x = 0; x < width; ++x) {
                 auto xcn = x * cn;
                 auto alpha = *(s + xcn + ac);
                 if (alpha > 0)
                     *(s + xcn + c) = ((*(s + xcn + c) + (alpha - max + 1) / 2) * max + alpha / 2) / alpha;
             }
         }
     }
 }
 
 inline void monoInvert(uchar *target, const char* source, qint32 bytes)
 {
     auto s = reinterpret_cast<const quint8*>(source);
     auto t = reinterpret_cast<quint8*>(target);
     for (qint32 x = 0; x < bytes; ++x) {
         t[x] = ~s[x];
     }
 }
 
 template<class T>
 inline void rawChannelsCopy(uchar *target, qint32 targetChannels, const char *source, qint32 sourceChannels, qint32 width)
 {
     auto s = reinterpret_cast<const T*>(source);
     auto t = reinterpret_cast<T*>(target);
     for (qint32 c = 0, cs = std::min(targetChannels, sourceChannels); c < cs; ++c) {
         for (qint32 x = 0; x < width; ++x) {
             t[x * targetChannels + c] = s[x * sourceChannels + c];
         }
     }
 }
 
 template<class T>
 inline void cmykToRgb(uchar *target, qint32 targetChannels, const char *source, qint32 sourceChannels, qint32 width, bool alpha = false)
 {
     auto s = reinterpret_cast<const T*>(source);
     auto t = reinterpret_cast<T*>(target);
     auto max = double(std::numeric_limits<T>::max());
     auto invmax = 1.0 / max; // speed improvements by ~10%
 
     if (sourceChannels < 3) {
         qDebug() << "cmykToRgb: image is not a valid CMY/CMYK!";
         return;
     }
 
     for (qint32 w = 0; w < width; ++w) {
         auto ps = s + sourceChannels * w;
         auto C = 1 - *(ps + 0) * invmax;
         auto M = 1 - *(ps + 1) * invmax;
         auto Y = 1 - *(ps + 2) * invmax;
         auto K = sourceChannels > 3 ? 1 - *(ps + 3) * invmax : 0.0;
 
         auto pt = t + targetChannels * w;
         *(pt + 0) = T(std::min(max - (C * (1 - K) + K) * max + 0.5, max));
         *(pt + 1) = T(std::min(max - (M * (1 - K) + K) * max + 0.5, max));
         *(pt + 2) = T(std::min(max - (Y * (1 - K) + K) * max + 0.5, max));
         if (targetChannels == 4) {
             if (sourceChannels >= 5 && alpha)
                 *(pt + 3) = *(ps + 4);
             else
                 *(pt + 3) = std::numeric_limits<T>::max();
         }
     }
 }
 
 inline double finv(double v)
 {
     return (v > 6.0 / 29.0 ? v * v * v : (v - 16.0 / 116.0) / 7.787);
 }
 
 inline double gammaCorrection(double linear)
 {
 #ifdef PSD_FAST_LAB_CONVERSION
     return linear;
 #else
     // Replacing fastPow with std::pow the conversion time is 2/3 times longer: using fastPow
     // there are minimal differences in the conversion that are not visually noticeable.
     return (linear > 0.0031308 ? 1.055 * fastPow(linear, 1.0 / 2.4) - 0.055 : 12.92 * linear);
 #endif
 }
 
 template<class T>
 inline void labToRgb(uchar *target, qint32 targetChannels, const char *source, qint32 sourceChannels, qint32 width, bool alpha = false)
 {
     auto s = reinterpret_cast<const T*>(source);
     auto t = reinterpret_cast<T*>(target);
     auto max = double(std::numeric_limits<T>::max());
     auto invmax = 1.0 / max;
 
     if (sourceChannels < 3) {
         qDebug() << "labToRgb: image is not a valid LAB!";
         return;
     }
 
     for (qint32 w = 0; w < width; ++w) {
         auto ps = s + sourceChannels * w;
         auto L = (*(ps + 0) * invmax) * 100.0;
         auto A = (*(ps + 1) * invmax) * 255.0 - 128.0;
         auto B = (*(ps + 2) * invmax) * 255.0 - 128.0;
 
         // converting LAB to XYZ (D65 illuminant)
         auto Y = (L + 16.0) * (1.0 / 116.0);
         auto X = A * (1.0 / 500.0) + Y;
         auto Z = Y - B * (1.0 / 200.0);
 
         // NOTE: use the constants of the illuminant of the target RGB color space
         X = finv(X) * 0.9504;   // D50: * 0.9642
         Y = finv(Y) * 1.0000;   // D50: * 1.0000
         Z = finv(Z) * 1.0888;   // D50: * 0.8251
 
         // converting XYZ to sRGB (sRGB illuminant is D65)
         auto r = gammaCorrection(  3.24071   * X - 1.53726  * Y - 0.498571  * Z);
         auto g = gammaCorrection(- 0.969258  * X + 1.87599  * Y + 0.0415557 * Z);
         auto b = gammaCorrection(  0.0556352 * X - 0.203996 * Y + 1.05707   * Z);
 
         auto pt = t + targetChannels * w;
         *(pt + 0) = T(std::max(std::min(r * max + 0.5, max), 0.0));
         *(pt + 1) = T(std::max(std::min(g * max + 0.5, max), 0.0));
         *(pt + 2) = T(std::max(std::min(b * max + 0.5, max), 0.0));
         if (targetChannels == 4) {
             if (sourceChannels >= 4 && alpha)
                 *(pt + 3) = *(ps + 3);
             else
                 *(pt + 3) = std::numeric_limits<T>::max();
         }
     }
 }
 
 bool readChannel(QByteArray& target, QDataStream &stream, quint32 compressedSize, quint16 compression)
 {
     if (compression) {
         if (compressedSize > kMaxQVectorSize) {
             return false;
         }
         QByteArray tmp;
         tmp.resize(compressedSize);
         if (stream.readRawData(tmp.data(), tmp.size()) != tmp.size()) {
             return false;
         }
         if (decompress(tmp.data(), tmp.size(), target.data(), target.size()) < 0) {
             return false;
         }
     }
     else if (stream.readRawData(target.data(), target.size()) != target.size()) {
         return false;
     }
 
     return stream.status() == QDataStream::Ok;
 }
 
 // Load the PSD image.
 static bool LoadPSD(QDataStream &stream, const PSDHeader &header, QImage &img)
 {
     // Checking for PSB
     auto isPsb = header.version == 2;
     bool ok = false;
 
     // Color Mode Data section
     auto cmds = readColorModeDataSection(stream, &ok);
     if (!ok) {
         qDebug() << "Error while skipping Color Mode Data section";
         return false;
     }
 
     // Image Resources Section
     auto irs = readImageResourceSection(stream, &ok);
     if (!ok) {
         qDebug() << "Error while reading Image Resources Section";
         return false;
     }
     // Checking for merged image (Photoshop compatibility data)
     if (!hasMergedData(irs)) {
         qDebug() << "No merged data found";
         return false;
     }
 
     // Layer and Mask section
     auto lms = readLayerAndMaskSection(stream, isPsb, &ok);
     if (!ok) {
         qDebug() << "Error while skipping Layer and Mask section";
         return false;
     }
 
     // Find out if the data is compressed.
     // Known values:
     //   0: no compression
     //   1: RLE compressed
     quint16 compression;
     stream >> compression;
     if (compression > 1) {
         qDebug() << "Unknown compression type";
         return false;
     }
 
     // Try to identify the nature of spots: note that this is just one of many ways to identify the presence
     // of alpha channels: should work in most cases where colorspaces != RGB/Gray
     auto alpha = header.color_mode == CM_RGB;
     if (!lms.isNull())
         alpha = lms.hasAlpha();
 
     const QImage::Format format = imageFormat(header, alpha);
     if (format == QImage::Format_Invalid) {
         qWarning() << "Unsupported image format. color_mode:" << header.color_mode << "depth:" << header.depth << "channel_count:" << header.channel_count;
         return false;
     }
 
     img = imageAlloc(header.width, header.height, format);
     if (img.isNull()) {
         qWarning() << "Failed to allocate image, invalid dimensions?" << QSize(header.width, header.height);
         return false;
     }
     img.fill(qRgb(0, 0, 0));
     if (!cmds.palette.isEmpty()) {
         img.setColorTable(cmds.palette);
         setTransparencyIndex(img, irs);
     }
 
     auto imgChannels = imageChannels(img.format());
     auto channel_num = std::min(qint32(header.channel_count), imgChannels);
     auto raw_count = qsizetype(header.width * header.depth + 7) / 8;
 
     if (header.height > kMaxQVectorSize / header.channel_count / sizeof(quint32)) {
         qWarning() << "LoadPSD() header height/channel_count too big" << header.height << header.channel_count;
         return false;
     }
 
     QList<quint32> strides(header.height * header.channel_count, raw_count);
     // Read the compressed stride sizes
     if (compression) {
         for (auto&& v : strides) {
             if (isPsb) {
                 stream >> v;
                 continue;
             }
             quint16 tmp;
             stream >> tmp;
             v = tmp;
         }
     }
     // calculate the absolute file positions of each stride (required when a colorspace conversion should be done)
     auto device = stream.device();
     QList<quint64> stridePositions(strides.size());
     if (!stridePositions.isEmpty()) {
         stridePositions[0] = device->pos();
     }
     for (qsizetype i = 1, n = stridePositions.size(); i < n; ++i) {
         stridePositions[i] = stridePositions[i-1] + strides.at(i-1);
     }
 
     // Read the image
     QByteArray rawStride;
     rawStride.resize(raw_count);
 
     // clang-format off
     // checks the need of color conversion (that requires random access to the image)
     auto randomAccess = (header.color_mode == CM_CMYK) ||
                         (header.color_mode == CM_LABCOLOR) ||
                         (header.color_mode == CM_MULTICHANNEL) ||
                         (header.color_mode != CM_INDEXED && img.hasAlphaChannel());
     // clang-format on
 
     if (randomAccess) {
         // In order to make a colorspace transformation, we need all channels of a scanline
         QByteArray psdScanline;
         psdScanline.resize(qsizetype(header.width * header.depth * header.channel_count + 7) / 8);
         for (qint32 y = 0, h = header.height; y < h; ++y) {
             for (qint32 c = 0; c < header.channel_count; ++c) {
                 auto strideNumber = c * qsizetype(h) + y;
                 if (!device->seek(stridePositions.at(strideNumber))) {
                     qDebug() << "Error while seeking the stream of channel" << c << "line" << y;
                     return false;
                 }
                 auto&& strideSize = strides.at(strideNumber);
                 if (!readChannel(rawStride, stream, strideSize, compression)) {
                     qDebug() << "Error while reading the stream of channel" << c << "line" << y;
                     return false;
                 }
 
                 auto scanLine = reinterpret_cast<unsigned char*>(psdScanline.data());
                 if (header.depth == 8) {
                     planarToChunchy<quint8>(scanLine, rawStride.data(), header.width, c, header.channel_count);
                 }
                 else if (header.depth == 16) {
                     planarToChunchy<quint16>(scanLine, rawStride.data(), header.width, c, header.channel_count);
                 }
                 else if (header.depth == 32) {
                     planarToChunchy<float>(scanLine, rawStride.data(), header.width, c, header.channel_count);
                 }
             }
 
             // Convert premultiplied data to unassociated data
             if (img.hasAlphaChannel()) {
                 auto scanLine = reinterpret_cast<char*>(psdScanline.data());
                 if (header.color_mode == CM_CMYK) {
                     if (header.depth == 8)
                         premulConversion<quint8>(scanLine, header.width, 4, header.channel_count, PremulConversion::PS2A);
                     else if (header.depth == 16)
                         premulConversion<quint16>(scanLine, header.width, 4, header.channel_count, PremulConversion::PS2A);
                 }
                 if (header.color_mode == CM_LABCOLOR) {
                     if (header.depth == 8)
                         premulConversion<quint8>(scanLine, header.width, 3, header.channel_count, PremulConversion::PSLab2A);
                     else if (header.depth == 16)
                         premulConversion<quint16>(scanLine, header.width, 3, header.channel_count, PremulConversion::PSLab2A);
                 }
                 if (header.color_mode == CM_RGB) {
                     if (header.depth == 8)
                         premulConversion<quint8>(scanLine, header.width, 3, header.channel_count, PremulConversion::PS2P);
                     else if (header.depth == 16)
                         premulConversion<quint16>(scanLine, header.width, 3, header.channel_count, PremulConversion::PS2P);
                     else if (header.depth == 32)
                         premulConversion<float>(scanLine, header.width, 3, header.channel_count, PremulConversion::PS2P);
                 }
             }
 
             // Conversion to RGB
             if (header.color_mode == CM_CMYK || header.color_mode == CM_MULTICHANNEL) {
                 if (header.depth == 8)
                     cmykToRgb<quint8>(img.scanLine(y), imgChannels, psdScanline.data(), header.channel_count, header.width, alpha);
                 else if (header.depth == 16)
                     cmykToRgb<quint16>(img.scanLine(y), imgChannels, psdScanline.data(), header.channel_count, header.width, alpha);
             }
             if (header.color_mode == CM_LABCOLOR) {
                 if (header.depth == 8)
                     labToRgb<quint8>(img.scanLine(y), imgChannels, psdScanline.data(), header.channel_count, header.width, alpha);
                 else if (header.depth == 16)
                     labToRgb<quint16>(img.scanLine(y), imgChannels, psdScanline.data(), header.channel_count, header.width, alpha);
             }
             if (header.color_mode == CM_RGB) {
                 if (header.depth == 8)
                     rawChannelsCopy<quint8>(img.scanLine(y), imgChannels, psdScanline.data(), header.channel_count, header.width);
                 else if (header.depth == 16)
                     rawChannelsCopy<quint16>(img.scanLine(y), imgChannels, psdScanline.data(), header.channel_count, header.width);
                 else if (header.depth == 32)
                     rawChannelsCopy<float>(img.scanLine(y), imgChannels, psdScanline.data(), header.channel_count, header.width);
             }
         }
     }
     else {
         // Linear read (no position jumps): optimized code usable only for the colorspaces supported by QImage
         for (qint32 c = 0; c < channel_num; ++c) {
             for (qint32 y = 0, h = header.height; y < h; ++y) {
                 auto&& strideSize = strides.at(c * qsizetype(h) + y);
                 if (!readChannel(rawStride, stream, strideSize, compression)) {
                     qDebug() << "Error while reading the stream of channel" << c << "line" << y;
                     return false;
                 }
 
                 auto scanLine = img.scanLine(y);
                 if (header.depth == 1) { // Bitmap
                     monoInvert(scanLine, rawStride.data(), std::min(rawStride.size(), img.bytesPerLine()));
                 }
                 else if (header.depth == 8) { // 8-bits images: Indexed, Grayscale, RGB/RGBA
                     planarToChunchy<quint8>(scanLine, rawStride.data(), header.width, c, imgChannels);
                 }
                 else if (header.depth == 16) { // 16-bits integer images: Grayscale, RGB/RGBA
                     planarToChunchy<quint16>(scanLine, rawStride.data(), header.width, c, imgChannels);
                 }
                 else if (header.depth == 32 && header.color_mode == CM_RGB) { // 32-bits float images: RGB/RGBA
                     planarToChunchy<float>(scanLine, rawStride.data(), header.width, c, imgChannels);
                 }
                 else if (header.depth == 32 && header.color_mode == CM_GRAYSCALE) { // 32-bits float images: Grayscale (coverted to equivalent integer 16-bits)
                     planarToChunchyFloatToUInt16<float>(scanLine, rawStride.data(), header.width, c, imgChannels);
                 }
             }
         }
     }
 
 
     // Resolution info
     if (!setResolution(img, irs)) {
         // qDebug() << "No resolution info found!";
     }
 
     // ICC profile
     if (header.color_mode == CM_LABCOLOR) {
         // LAB conversion generates a sRGB image
 #ifdef PSD_FAST_LAB_CONVERSION
         img.setColorSpace(QColorSpace(QColorSpace::SRgbLinear));
 #else
         img.setColorSpace(QColorSpace(QColorSpace::SRgb));
 #endif
     }
     else if (!setColorSpace(img, irs)) {
         // qDebug() << "No colorspace info set!";
     }
 
     // XMP data
     if (!setXmpData(img, irs)) {
         // qDebug() << "No XMP data found!";
     }
 
     // Duotone images: color data contains the duotone specification (not documented).
     // Other applications that read Photoshop files can treat a duotone image as a gray image,
     // and just preserve the contents of the duotone information when reading and writing the file.
     if (!cmds.duotone.data.isEmpty()) {
         img.setText(QStringLiteral("PSDDuotoneOptions"), QString::fromUtf8(cmds.duotone.data.toHex()));
     }
 
     return true;
 }
 
 } // Private
 
 PSDHandler::PSDHandler()
 {
 }
 
 bool PSDHandler::canRead() const
 {
     if (canRead(device())) {
         setFormat("psd");
         return true;
     }
     return false;
 }
 
 bool PSDHandler::read(QImage *image)
 {
     QDataStream s(device());
     s.setByteOrder(QDataStream::BigEndian);
 
     PSDHeader header;
     s >> header;
 
     // Check image file format.
     if (s.atEnd() || !IsValid(header)) {
         //         qDebug() << "This PSD file is not valid.";
         return false;
     }
 
     // Check if it's a supported format.
     if (!IsSupported(header)) {
         //         qDebug() << "This PSD file is not supported.";
         return false;
     }
 
     QImage img;
     if (!LoadPSD(s, header, img)) {
         //         qDebug() << "Error loading PSD file.";
         return false;
     }
 
     *image = img;
     return true;
 }
 
 bool PSDHandler::supportsOption(ImageOption option) const
 {
     if (option == QImageIOHandler::Size)
         return true;
     return false;
 }
 
 QVariant PSDHandler::option(ImageOption option) const
 {
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
         if (auto d = device()) {
             // transactions works on both random and sequential devices
             d->startTransaction();
             auto ba = d->read(sizeof(PSDHeader));
             d->rollbackTransaction();
 
             QDataStream s(ba);
             s.setByteOrder(QDataStream::BigEndian);
 
             PSDHeader header;
             s >> header;
 
             if (s.status() == QDataStream::Ok && IsValid(header))
                 v = QVariant::fromValue(QSize(header.width, header.height));
         }
     }
 
     return v;
 }
 
 bool PSDHandler::canRead(QIODevice *device)
 {
     if (!device) {
         qWarning("PSDHandler::canRead() called with no device");
         return false;
     }
 
     device->startTransaction();
 
     QDataStream s(device);
     s.setByteOrder(QDataStream::BigEndian);
 
     PSDHeader header;
     s >> header;
 
     device->rollbackTransaction();
 
     if (s.status() != QDataStream::Ok) {
         return false;
     }
 
     if (device->isSequential()) {
         if (header.color_mode == CM_CMYK || header.color_mode == CM_LABCOLOR || header.color_mode == CM_MULTICHANNEL) {
             return false;
         }
         if (header.color_mode == CM_RGB && header.channel_count > 3) {
             return false; // supposing extra channel as alpha
         }
     }
 
     return IsSupported(header);
 }
 
 QImageIOPlugin::Capabilities PSDPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
     if (format == "psd" || format == "psb" || format == "pdd" || format == "psdt") {
         return Capabilities(CanRead);
     }
     if (!format.isEmpty()) {
         return {};
     }
     if (!device->isOpen()) {
         return {};
     }
 
     Capabilities cap;
     if (device->isReadable() && PSDHandler::canRead(device)) {
         cap |= CanRead;
     }
     return cap;
 }
 
 QImageIOHandler *PSDPlugin::create(QIODevice *device, const QByteArray &format) const
 {
     QImageIOHandler *handler = new PSDHandler;
     handler->setDevice(device);
     handler->setFormat(format);
     return handler;
 }
 
 #include "moc_psd_p.cpp"