Initial import from the monolithic Qt.

This is the beginning of revision history for this module. If you
want to look at revision history older than this, please refer to the
Qt Git wiki for how to use Git history grafting. At the time of
writing, this wiki is located here:

http://qt.gitorious.org/qt/pages/GitIntroductionWithQt

If you have already performed the grafting and you don't see any
history beyond this commit, try running "git log" with the "--follow"
argument.

Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12

1 files changed, 1214 insertions, 0 deletions

diff --git a/src/gui/image/qgifhandler.cpp b/src/gui/image/qgifhandler.cpp
new file mode 100644
index 0000000000..7cb7373b44
--- /dev/null
+++ b/src/gui/image/qgifhandler.cpp
@@ -0,0 +1,1214 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+** WARNING:
+**      A separate license from Unisys may be required to use the gif
+**      reader. See http://www.unisys.com/about__unisys/lzw/
+**      for information from Unisys
+**
+****************************************************************************/
+
+#include "qgifhandler_p.h"
+
+#include <qimage.h>
+#include <qiodevice.h>
+#include <qvariant.h>
+
+QT_BEGIN_NAMESPACE
+
+#define Q_TRANSPARENT 0x00ffffff
+
+// avoid going through QImage::scanLine() which calls detach
+#define FAST_SCAN_LINE(bits, bpl, y) (bits + (y) * bpl)
+
+
+/*
+  Incremental image decoder for GIF image format.
+
+  This subclass of QImageFormat decodes GIF format images,
+  including animated GIFs. Internally in
+*/
+
+class QGIFFormat {
+public:
+    QGIFFormat();
+    ~QGIFFormat();
+
+    int decode(QImage *image, const uchar* buffer, int length,
+               int *nextFrameDelay, int *loopCount);
+    static void scan(QIODevice *device, QVector<QSize> *imageSizes, int *loopCount);
+
+    bool newFrame;
+    bool partialNewFrame;
+
+private:
+    void fillRect(QImage *image, int x, int y, int w, int h, QRgb col);
+    inline QRgb color(uchar index) const;
+
+    // GIF specific stuff
+    QRgb* globalcmap;
+    QRgb* localcmap;
+    QImage backingstore;
+    unsigned char hold[16];
+    bool gif89;
+    int count;
+    int ccount;
+    int expectcount;
+    enum State {
+        Header,
+        LogicalScreenDescriptor,
+        GlobalColorMap,
+        LocalColorMap,
+        Introducer,
+        ImageDescriptor,
+        TableImageLZWSize,
+        ImageDataBlockSize,
+        ImageDataBlock,
+        ExtensionLabel,
+        GraphicControlExtension,
+        ApplicationExtension,
+        NetscapeExtensionBlockSize,
+        NetscapeExtensionBlock,
+        SkipBlockSize,
+        SkipBlock,
+        Done,
+        Error
+    } state;
+    int gncols;
+    int lncols;
+    int ncols;
+    int lzwsize;
+    bool lcmap;
+    int swidth, sheight;
+    int width, height;
+    int left, top, right, bottom;
+    enum Disposal { NoDisposal, DoNotChange, RestoreBackground, RestoreImage };
+    Disposal disposal;
+    bool disposed;
+    int trans_index;
+    bool gcmap;
+    int bgcol;
+    int interlace;
+    int accum;
+    int bitcount;
+
+    enum { max_lzw_bits=12 }; // (poor-compiler's static const int)
+
+    int code_size, clear_code, end_code, max_code_size, max_code;
+    int firstcode, oldcode, incode;
+    short* table[2];
+    short* stack;
+    short *sp;
+    bool needfirst;
+    int x, y;
+    int frame;
+    bool out_of_bounds;
+    bool digress;
+    void nextY(unsigned char *bits, int bpl);
+    void disposePrevious(QImage *image);
+};
+
+/*!
+    Constructs a QGIFFormat.
+*/
+QGIFFormat::QGIFFormat()
+{
+    globalcmap = 0;
+    localcmap = 0;
+    lncols = 0;
+    gncols = 0;
+    disposal = NoDisposal;
+    out_of_bounds = false;
+    disposed = true;
+    frame = -1;
+    state = Header;
+    count = 0;
+    lcmap = false;
+    newFrame = false;
+    partialNewFrame = false;
+    table[0] = 0;
+    table[1] = 0;
+    stack = 0;
+}
+
+/*!
+    Destroys a QGIFFormat.
+*/
+QGIFFormat::~QGIFFormat()
+{
+    if (globalcmap) delete[] globalcmap;
+    if (localcmap) delete[] localcmap;
+    delete [] stack;
+}
+
+void QGIFFormat::disposePrevious(QImage *image)
+{
+    if (out_of_bounds) {
+        // flush anything that survived
+        // ### Changed: QRect(0, 0, swidth, sheight)
+    }
+
+    // Handle disposal of previous image before processing next one
+
+    if (disposed) return;
+
+    int l = qMin(swidth-1,left);
+    int r = qMin(swidth-1,right);
+    int t = qMin(sheight-1,top);
+    int b = qMin(sheight-1,bottom);
+
+    switch (disposal) {
+      case NoDisposal:
+        break;
+      case DoNotChange:
+        break;
+      case RestoreBackground:
+        if (trans_index>=0) {
+            // Easy:  we use the transparent color
+            fillRect(image, l, t, r-l+1, b-t+1, Q_TRANSPARENT);
+        } else if (bgcol>=0) {
+            // Easy:  we use the bgcol given
+            fillRect(image, l, t, r-l+1, b-t+1, color(bgcol));
+        } else {
+            // Impossible:  We don't know of a bgcol - use pixel 0
+            QRgb *bits = (QRgb*)image->bits();
+            fillRect(image, l, t, r-l+1, b-t+1, bits[0]);
+        }
+        // ### Changed: QRect(l, t, r-l+1, b-t+1)
+        break;
+      case RestoreImage: {
+        if (frame >= 0) {
+            for (int ln=t; ln<=b; ln++) {
+                memcpy(image->scanLine(ln)+l,
+                    backingstore.scanLine(ln-t),
+                    (r-l+1)*sizeof(QRgb));
+            }
+            // ### Changed: QRect(l, t, r-l+1, b-t+1)
+        }
+      }
+    }
+    disposal = NoDisposal; // Until an extension says otherwise.
+
+    disposed = true;
+}
+
+/*!
+    This function decodes some data into image changes.
+
+    Returns the number of bytes consumed.
+*/
+int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
+                       int *nextFrameDelay, int *loopCount)
+{
+    // We are required to state that
+    //    "The Graphics Interchange Format(c) is the Copyright property of
+    //    CompuServe Incorporated. GIF(sm) is a Service Mark property of
+    //    CompuServe Incorporated."
+
+    if (!stack) {
+        stack = new short[(1 << max_lzw_bits) * 4];
+        table[0] = &stack[(1 << max_lzw_bits) * 2];
+        table[1] = &stack[(1 << max_lzw_bits) * 3];
+    }
+
+    image->detach();
+    int bpl = image->bytesPerLine();
+    unsigned char *bits = image->bits();
+
+#define LM(l, m) (((m)<<8)|l)
+    digress = false;
+    const int initial = length;
+    while (!digress && length) {
+        length--;
+        unsigned char ch=*buffer++;
+        switch (state) {
+          case Header:
+            hold[count++]=ch;
+            if (count==6) {
+                // Header
+                gif89=(hold[3]!='8' || hold[4]!='7');
+                state=LogicalScreenDescriptor;
+                count=0;
+            }
+            break;
+          case LogicalScreenDescriptor:
+            hold[count++]=ch;
+            if (count==7) {
+                // Logical Screen Descriptor
+                swidth=LM(hold[0], hold[1]);
+                sheight=LM(hold[2], hold[3]);
+                gcmap=!!(hold[4]&0x80);
+                //UNUSED: bpchan=(((hold[4]&0x70)>>3)+1);
+                //UNUSED: gcmsortflag=!!(hold[4]&0x08);
+                gncols=2<<(hold[4]&0x7);
+                bgcol=(gcmap) ? hold[5] : -1;
+                //aspect=hold[6] ? double(hold[6]+15)/64.0 : 1.0;
+
+                trans_index = -1;
+                count=0;
+                ncols=gncols;
+                if (gcmap) {
+                    ccount=0;
+                    state=GlobalColorMap;
+                    globalcmap = new QRgb[gncols+1]; // +1 for trans_index
+                    globalcmap[gncols] = Q_TRANSPARENT;
+                } else {
+                    state=Introducer;
+                }
+            }
+            break;
+          case GlobalColorMap: case LocalColorMap:
+            hold[count++]=ch;
+            if (count==3) {
+                QRgb rgb = qRgb(hold[0], hold[1], hold[2]);
+                if (state == LocalColorMap) {
+                    if (ccount < lncols)
+                        localcmap[ccount] =  rgb;
+                } else {
+                    globalcmap[ccount] = rgb;
+                }
+                if (++ccount >= ncols) {
+                    if (state == LocalColorMap)
+                        state=TableImageLZWSize;
+                    else
+                        state=Introducer;
+                }
+                count=0;
+            }
+            break;
+          case Introducer:
+            hold[count++]=ch;
+            switch (ch) {
+              case ',':
+                state=ImageDescriptor;
+                break;
+              case '!':
+                state=ExtensionLabel;
+                break;
+              case ';':
+                  // ### Changed: QRect(0, 0, swidth, sheight)
+                state=Done;
+                break;
+              default:
+                digress=true;
+                // Unexpected Introducer - ignore block
+                state=Error;
+            }
+            break;
+          case ImageDescriptor:
+            hold[count++]=ch;
+            if (count==10) {
+                int newleft=LM(hold[1], hold[2]);
+                int newtop=LM(hold[3], hold[4]);
+                int newwidth=LM(hold[5], hold[6]);
+                int newheight=LM(hold[7], hold[8]);
+
+                // disbelieve ridiculous logical screen sizes,
+                // unless the image frames are also large.
+                if (swidth/10 > qMax(newwidth,200))
+                    swidth = -1;
+                if (sheight/10 > qMax(newheight,200))
+                    sheight = -1;
+
+                if (swidth <= 0)
+                    swidth = newleft + newwidth;
+                if (sheight <= 0)
+                    sheight = newtop + newheight;
+
+                QImage::Format format = trans_index >= 0 ? QImage::Format_ARGB32 : QImage::Format_RGB32;
+                if (image->isNull()) {
+                    (*image) = QImage(swidth, sheight, format);
+                    bpl = image->bytesPerLine();
+                    bits = image->bits();
+                    memset(bits, 0, image->byteCount());
+                }
+
+                disposePrevious(image);
+                disposed = false;
+
+                left = newleft;
+                top = newtop;
+                width = newwidth;
+                height = newheight;
+
+                right=qMax(0, qMin(left+width, swidth)-1);
+                bottom=qMax(0, qMin(top+height, sheight)-1);
+                lcmap=!!(hold[9]&0x80);
+                interlace=!!(hold[9]&0x40);
+                //bool lcmsortflag=!!(hold[9]&0x20);
+                lncols=lcmap ? (2<<(hold[9]&0x7)) : 0;
+                if (lncols) {
+                    if (localcmap)
+                        delete [] localcmap;
+                    localcmap = new QRgb[lncols+1];
+                    localcmap[lncols] = Q_TRANSPARENT;
+                    ncols = lncols;
+                } else {
+                    ncols = gncols;
+                }
+                frame++;
+                if (frame == 0) {
+                    if (left || top || width<swidth || height<sheight) {
+                        // Not full-size image - erase with bg or transparent
+                        if (trans_index >= 0) {
+                            fillRect(image, 0, 0, swidth, sheight, color(trans_index));
+                            // ### Changed: QRect(0, 0, swidth, sheight)
+                        } else if (bgcol>=0) {
+                            fillRect(image, 0, 0, swidth, sheight, color(bgcol));
+                            // ### Changed: QRect(0, 0, swidth, sheight)
+                        }
+                    }
+                }
+
+                if (disposal == RestoreImage) {
+                    int l = qMin(swidth-1,left);
+                    int r = qMin(swidth-1,right);
+                    int t = qMin(sheight-1,top);
+                    int b = qMin(sheight-1,bottom);
+                    int w = r-l+1;
+                    int h = b-t+1;
+
+                    if (backingstore.width() < w
+                        || backingstore.height() < h) {
+                        // We just use the backing store as a byte array
+                        backingstore = QImage(qMax(backingstore.width(), w),
+                                              qMax(backingstore.height(), h),
+                                              QImage::Format_RGB32);
+                        memset(bits, 0, image->byteCount());
+                    }
+                    const int dest_bpl = backingstore.bytesPerLine();
+                    unsigned char *dest_data = backingstore.bits();
+                    for (int ln=0; ln<h; ln++) {
+                        memcpy(FAST_SCAN_LINE(dest_data, dest_bpl, ln),
+                               FAST_SCAN_LINE(bits, bpl, t+ln) + l, w*sizeof(QRgb));
+                    }
+                }
+
+                count=0;
+                if (lcmap) {
+                    ccount=0;
+                    state=LocalColorMap;
+                } else {
+                    state=TableImageLZWSize;
+                }
+                x = left;
+                y = top;
+                accum = 0;
+                bitcount = 0;
+                sp = stack;
+                firstcode = oldcode = 0;
+                needfirst = true;
+                out_of_bounds = left>=swidth || y>=sheight;
+            }
+            break;
+          case TableImageLZWSize: {
+            lzwsize=ch;
+            if (lzwsize > max_lzw_bits) {
+                state=Error;
+            } else {
+                code_size=lzwsize+1;
+                clear_code=1<<lzwsize;
+                end_code=clear_code+1;
+                max_code_size=2*clear_code;
+                max_code=clear_code+2;
+                int i;
+                for (i=0; i<clear_code; i++) {
+                    table[0][i]=0;
+                    table[1][i]=i;
+                }
+                state=ImageDataBlockSize;
+            }
+            count=0;
+            break;
+          } case ImageDataBlockSize:
+            expectcount=ch;
+            if (expectcount) {
+                state=ImageDataBlock;
+            } else {
+                state=Introducer;
+                digress = true;
+                newFrame = true;
+            }
+            break;
+          case ImageDataBlock:
+            count++;
+            accum|=(ch<<bitcount);
+            bitcount+=8;
+            while (bitcount>=code_size && state==ImageDataBlock) {
+                int code=accum&((1<<code_size)-1);
+                bitcount-=code_size;
+                accum>>=code_size;
+
+                if (code==clear_code) {
+                    if (!needfirst) {
+                        code_size=lzwsize+1;
+                        max_code_size=2*clear_code;
+                        max_code=clear_code+2;
+                    }
+                    needfirst=true;
+                } else if (code==end_code) {
+                    bitcount = -32768;
+                    // Left the block end arrive
+                } else {
+                    if (needfirst) {
+                        firstcode=oldcode=code;
+                        if (!out_of_bounds && image->height() > y && firstcode!=trans_index)
+                            ((QRgb*)FAST_SCAN_LINE(bits, bpl, y))[x] = color(firstcode);
+                        x++;
+                        if (x>=swidth) out_of_bounds = true;
+                        needfirst=false;
+                        if (x>=left+width) {
+                            x=left;
+                            out_of_bounds = left>=swidth || y>=sheight;
+                            nextY(bits, bpl);
+                        }
+                    } else {
+                        incode=code;
+                        if (code>=max_code) {
+                            *sp++=firstcode;
+                            code=oldcode;
+                        }
+                        while (code>=clear_code+2) {
+                            if (code >= max_code) {
+                                state = Error;
+                                return -1;
+                            }
+                            *sp++=table[1][code];
+                            if (code==table[0][code]) {
+                                state=Error;
+                                return -1;
+                            }
+                            if (sp-stack>=(1<<(max_lzw_bits))*2) {
+                                state=Error;
+                                return -1;
+                            }
+                            code=table[0][code];
+                        }
+                        if (code < 0) {
+                            state = Error;
+                            return -1;
+                        }
+
+                        *sp++=firstcode=table[1][code];
+                        code=max_code;
+                        if (code<(1<<max_lzw_bits)) {
+                            table[0][code]=oldcode;
+                            table[1][code]=firstcode;
+                            max_code++;
+                            if ((max_code>=max_code_size)
+                             && (max_code_size<(1<<max_lzw_bits)))
+                            {
+                                max_code_size*=2;
+                                code_size++;
+                            }
+                        }
+                        oldcode=incode;
+                        const int h = image->height();
+                        const QRgb *map = lcmap ? localcmap : globalcmap;
+                        QRgb *line = 0;
+                        if (!out_of_bounds && h > y)
+                            line = (QRgb*)FAST_SCAN_LINE(bits, bpl, y);
+                        while (sp>stack) {
+                            const uchar index = *(--sp);
+                            if (!out_of_bounds && h > y && index!=trans_index) {
+                                if (index > ncols)
+                                    line[x] = Q_TRANSPARENT;
+                                else
+                                    line[x] = map ? map[index] : 0;
+                            }
+                            x++;
+                            if (x>=swidth) out_of_bounds = true;
+                            if (x>=left+width) {
+                                x=left;
+                                out_of_bounds = left>=swidth || y>=sheight;
+                                nextY(bits, bpl);
+                                if (!out_of_bounds && h > y)
+                                    line = (QRgb*)FAST_SCAN_LINE(bits, bpl, y);
+                            }
+                        }
+                    }
+                }
+            }
+            partialNewFrame = true;
+            if (count==expectcount) {
+                count=0;
+                state=ImageDataBlockSize;
+            }
+            break;
+          case ExtensionLabel:
+            switch (ch) {
+            case 0xf9:
+                state=GraphicControlExtension;
+                break;
+            case 0xff:
+                state=ApplicationExtension;
+                break;
+#if 0
+            case 0xfe:
+                state=CommentExtension;
+                break;
+            case 0x01:
+                break;
+#endif
+            default:
+                state=SkipBlockSize;
+            }
+            count=0;
+            break;
+          case ApplicationExtension:
+            if (count<11) hold[count]=ch;
+            count++;
+            if (count==hold[0]+1) {
+                if (qstrncmp((char*)(hold+1), "NETSCAPE", 8)==0) {
+                    // Looping extension
+                    state=NetscapeExtensionBlockSize;
+                } else {
+                    state=SkipBlockSize;
+                }
+                count=0;
+            }
+            break;
+          case NetscapeExtensionBlockSize:
+            expectcount=ch;
+            count=0;
+            if (expectcount) state=NetscapeExtensionBlock;
+            else state=Introducer;
+            break;
+          case NetscapeExtensionBlock:
+            if (count<3) hold[count]=ch;
+            count++;
+            if (count==expectcount) {
+                *loopCount = hold[1]+hold[2]*256;
+                state=SkipBlockSize; // Ignore further blocks
+            }
+            break;
+          case GraphicControlExtension:
+            if (count<5) hold[count]=ch;
+            count++;
+            if (count==hold[0]+1) {
+                disposePrevious(image);
+                disposal=Disposal((hold[1]>>2)&0x7);
+                //UNUSED: waitforuser=!!((hold[1]>>1)&0x1);
+                int delay=count>3 ? LM(hold[2], hold[3]) : 1;
+                // IE and mozilla use a minimum delay of 10. With the minimum delay of 10
+                // we are compatible to them and avoid huge loads on the app and xserver.
+                *nextFrameDelay = (delay < 2 ? 10 : delay) * 10;
+
+                bool havetrans=hold[1]&0x1;
+                trans_index = havetrans ? hold[4] : -1;
+
+                count=0;
+                state=SkipBlockSize;
+            }
+            break;
+          case SkipBlockSize:
+            expectcount=ch;
+            count=0;
+            if (expectcount) state=SkipBlock;
+            else state=Introducer;
+            break;
+          case SkipBlock:
+            count++;
+            if (count==expectcount) state=SkipBlockSize;
+            break;
+          case Done:
+            digress=true;
+            /* Netscape ignores the junk, so we do too.
+            length++; // Unget
+            state=Error; // More calls to this is an error
+            */
+            break;
+          case Error:
+            return -1; // Called again after done.
+        }
+    }
+    return initial-length;
+}
+
+/*!
+   Scans through the data stream defined by \a device and returns the image
+   sizes found in the stream in the \a imageSizes vector.
+*/
+void QGIFFormat::scan(QIODevice *device, QVector<QSize> *imageSizes, int *loopCount)
+{
+    if (!device)
+        return;
+
+    qint64 oldPos = device->pos();
+    if (!device->seek(0))
+        return;
+
+    int colorCount = 0;
+    int localColorCount = 0;
+    int globalColorCount = 0;
+    int colorReadCount = 0;
+    bool localColormap = false;
+    bool globalColormap = false;
+    int count = 0;
+    int blockSize = 0;
+    int imageWidth = 0;
+    int imageHeight = 0;
+    bool done = false;
+    uchar hold[16];
+    State state = Header;
+
+    const int readBufferSize = 40960; // 40k read buffer
+    QByteArray readBuffer(device->read(readBufferSize));
+
+    if (readBuffer.isEmpty()) {
+        device->seek(oldPos);
+        return;
+    }
+
+    // This is a specialized version of the state machine from decode(),
+    // which doesn't do any image decoding or mallocing, and has an
+    // optimized way of skipping SkipBlocks, ImageDataBlocks and
+    // Global/LocalColorMaps.
+
+    while (!readBuffer.isEmpty()) {
+        int length = readBuffer.size();
+        const uchar *buffer = (const uchar *) readBuffer.constData();
+        while (!done && length) {
+            length--;
+            uchar ch = *buffer++;
+            switch (state) {
+            case Header:
+                hold[count++] = ch;
+                if (count == 6) {
+                    state = LogicalScreenDescriptor;
+                    count = 0;
+                }
+                break;
+            case LogicalScreenDescriptor:
+                hold[count++] = ch;
+                if (count == 7) {
+                    imageWidth = LM(hold[0], hold[1]);
+                    imageHeight = LM(hold[2], hold[3]);
+                    globalColormap = !!(hold[4] & 0x80);
+                    globalColorCount = 2 << (hold[4] & 0x7);
+                    count = 0;
+                    colorCount = globalColorCount;
+                    if (globalColormap) {
+                        int colorTableSize = 3 * globalColorCount;
+                        if (length >= colorTableSize) {
+                            // skip the global color table in one go
+                            length -= colorTableSize;
+                            buffer += colorTableSize;
+                            state = Introducer;
+                        } else {
+                            colorReadCount = 0;
+                            state = GlobalColorMap;
+                        }
+                    } else {
+                        state=Introducer;
+                    }
+                }
+                break;
+            case GlobalColorMap:
+            case LocalColorMap:
+                hold[count++] = ch;
+                if (count == 3) {
+                    if (++colorReadCount >= colorCount) {
+                        if (state == LocalColorMap)
+                            state = TableImageLZWSize;
+                        else
+                            state = Introducer;
+                    }
+                    count = 0;
+                }
+                break;
+            case Introducer:
+                hold[count++] = ch;
+                switch (ch) {
+                case 0x2c:
+                    state = ImageDescriptor;
+                    break;
+                case 0x21:
+                    state = ExtensionLabel;
+                    break;
+                case 0x3b:
+                    state = Done;
+                    break;
+                default:
+                    done = true;
+                    state = Error;
+                }
+                break;
+            case ImageDescriptor:
+                hold[count++] = ch;
+                if (count == 10) {
+                    int newLeft = LM(hold[1], hold[2]);
+                    int newTop = LM(hold[3], hold[4]);
+                    int newWidth = LM(hold[5], hold[6]);
+                    int newHeight = LM(hold[7], hold[8]);
+
+                    if (imageWidth/10 > qMax(newWidth,200))
+                        imageWidth = -1;
+                    if (imageHeight/10 > qMax(newHeight,200))
+                        imageHeight = -1;
+
+                    if (imageWidth <= 0)
+                        imageWidth = newLeft + newWidth;
+                    if (imageHeight <= 0)
+                        imageHeight = newTop + newHeight;
+
+                    *imageSizes << QSize(imageWidth, imageHeight);
+
+                    localColormap = !!(hold[9] & 0x80);
+                    localColorCount = localColormap ? (2 << (hold[9] & 0x7)) : 0;
+                    if (localColorCount)
+                        colorCount = localColorCount;
+                    else
+                        colorCount = globalColorCount;
+
+                    count = 0;
+                    if (localColormap) {
+                        int colorTableSize = 3 * localColorCount;
+                        if (length >= colorTableSize) {
+                            // skip the local color table in one go
+                            length -= colorTableSize;
+                            buffer += colorTableSize;
+                            state = TableImageLZWSize;
+                        } else {
+                            colorReadCount = 0;
+                            state = LocalColorMap;
+                        }
+                    } else {
+                        state = TableImageLZWSize;
+                    }
+                }
+                break;
+            case TableImageLZWSize:
+                if (ch > max_lzw_bits)
+                    state = Error;
+                else
+                    state = ImageDataBlockSize;
+                count = 0;
+                break;
+            case ImageDataBlockSize:
+                blockSize = ch;
+                if (blockSize) {
+                    if (length >= blockSize) {
+                        // we can skip the block in one go
+                        length -= blockSize;
+                        buffer += blockSize;
+                        count = 0;
+                    } else {
+                        state = ImageDataBlock;
+                    }
+                } else {
+                    state = Introducer;
+                }
+                break;
+            case ImageDataBlock:
+                ++count;
+                if (count == blockSize) {
+                    count = 0;
+                    state = ImageDataBlockSize;
+                }
+                break;
+            case ExtensionLabel:
+                switch (ch) {
+                case 0xf9:
+                    state = GraphicControlExtension;
+                    break;
+                case 0xff:
+                    state = ApplicationExtension;
+                    break;
+                default:
+                    state = SkipBlockSize;
+                }
+                count = 0;
+                break;
+            case ApplicationExtension:
+                if (count < 11)
+                    hold[count] = ch;
+                ++count;
+                if (count == hold[0] + 1) {
+                    if (qstrncmp((char*)(hold+1), "NETSCAPE", 8) == 0)
+                        state=NetscapeExtensionBlockSize;
+                    else
+                        state=SkipBlockSize;
+                    count = 0;
+                }
+                break;
+            case GraphicControlExtension:
+                if (count < 5)
+                    hold[count] = ch;
+                ++count;
+                if (count == hold[0] + 1) {
+                    count = 0;
+                    state = SkipBlockSize;
+                }
+                break;
+            case NetscapeExtensionBlockSize:
+                blockSize = ch;
+                count = 0;
+                if (blockSize)
+                    state = NetscapeExtensionBlock;
+                else
+                    state = Introducer;
+                break;
+            case NetscapeExtensionBlock:
+                if (count < 3)
+                    hold[count] = ch;
+                count++;
+                if (count == blockSize) {
+                    *loopCount = LM(hold[1], hold[2]);
+                    state = SkipBlockSize;
+                }
+                break;
+            case SkipBlockSize:
+                blockSize = ch;
+                count = 0;
+                if (blockSize) {
+                    if (length >= blockSize) {
+                        // we can skip the block in one go
+                        length -= blockSize;
+                        buffer += blockSize;
+                    } else {
+                        state = SkipBlock;
+                    }
+                } else {
+                    state = Introducer;
+                }
+                break;
+            case SkipBlock:
+                ++count;
+                if (count == blockSize)
+                    state = SkipBlockSize;
+                break;
+            case Done:
+                done = true;
+                break;
+            case Error:
+                device->seek(oldPos);
+                return;
+            }
+        }
+        readBuffer = device->read(readBufferSize);
+    }
+    device->seek(oldPos);
+    return;
+}
+
+void QGIFFormat::fillRect(QImage *image, int col, int row, int w, int h, QRgb color)
+{
+    if (w>0) {
+        for (int j=0; j<h; j++) {
+            QRgb *line = (QRgb*)image->scanLine(j+row);
+            for (int i=0; i<w; i++)
+                *(line+col+i) = color;
+        }
+    }
+}
+
+void QGIFFormat::nextY(unsigned char *bits, int bpl)
+{
+    int my;
+    switch (interlace) {
+    case 0: // Non-interlaced
+        // if (!out_of_bounds) {
+        //     ### Changed: QRect(left, y, right - left + 1, 1);
+        // }
+        y++;
+        break;
+    case 1: {
+        int i;
+        my = qMin(7, bottom-y);
+        // Don't dup with transparency
+        if (trans_index < 0) {
+            for (i=1; i<=my; i++) {
+                memcpy(FAST_SCAN_LINE(bits, bpl, y+i)+left*sizeof(QRgb), FAST_SCAN_LINE(bits, bpl, y)+left*sizeof(QRgb),
+                       (right-left+1)*sizeof(QRgb));
+            }
+        }
+
+        // if (!out_of_bounds) {
+        //     ### Changed: QRect(left, y, right - left + 1, my + 1);
+        // }
+//        if (!out_of_bounds)
+//            qDebug("consumer->changed(QRect(%d, %d, %d, %d))", left, y, right-left+1, my+1);
+        y+=8;
+        if (y>bottom) {
+            interlace++; y=top+4;
+            if (y > bottom) { // for really broken GIFs with bottom < 5
+                interlace=2;
+                y = top + 2;
+                if (y > bottom) { // for really broken GIF with bottom < 3
+                    interlace = 0;
+                    y = top + 1;
+                }
+            }
+        }
+    } break;
+    case 2: {
+        int i;
+        my = qMin(3, bottom-y);
+        // Don't dup with transparency
+        if (trans_index < 0) {
+            for (i=1; i<=my; i++) {
+                memcpy(FAST_SCAN_LINE(bits, bpl, y+i)+left*sizeof(QRgb), FAST_SCAN_LINE(bits, bpl, y)+left*sizeof(QRgb),
+                       (right-left+1)*sizeof(QRgb));
+            }
+        }
+
+        // if (!out_of_bounds) {
+        //     ### Changed: QRect(left, y, right - left + 1, my + 1);
+        // }
+        y+=8;
+        if (y>bottom) {
+            interlace++; y=top+2;
+            // handle broken GIF with bottom < 3
+            if (y > bottom) {
+                interlace = 3;
+                y = top + 1;
+            }
+        }
+    } break;
+    case 3: {
+        int i;
+        my = qMin(1, bottom-y);
+        // Don't dup with transparency
+        if (trans_index < 0) {
+            for (i=1; i<=my; i++) {
+                memcpy(FAST_SCAN_LINE(bits, bpl, y+i)+left*sizeof(QRgb), FAST_SCAN_LINE(bits, bpl, y)+left*sizeof(QRgb),
+                       (right-left+1)*sizeof(QRgb));
+            }
+        }
+        // if (!out_of_bounds) {
+        //     ### Changed: QRect(left, y, right - left + 1, my + 1);
+        // }
+        y+=4;
+        if (y>bottom) { interlace++; y=top+1; }
+    } break;
+    case 4:
+        // if (!out_of_bounds) {
+        //     ### Changed: QRect(left, y, right - left + 1, 1);
+        // }
+        y+=2;
+    }
+
+    // Consume bogus extra lines
+    if (y >= sheight) out_of_bounds=true; //y=bottom;
+}
+
+inline QRgb QGIFFormat::color(uchar index) const
+{
+    if (index == trans_index || index > ncols)
+        return Q_TRANSPARENT;
+
+    QRgb *map = lcmap ? localcmap : globalcmap;
+    return map ? map[index] : 0;
+}
+
+//-------------------------------------------------------------------------
+//-------------------------------------------------------------------------
+//-------------------------------------------------------------------------
+
+QGifHandler::QGifHandler()
+{
+    gifFormat = new QGIFFormat;
+    nextDelay = 100;
+    loopCnt = -1;
+    frameNumber = -1;
+    scanIsCached = false;
+}
+
+QGifHandler::~QGifHandler()
+{
+    delete gifFormat;
+}
+
+// Does partial decode if necessary, just to see if an image is coming
+
+bool QGifHandler::imageIsComing() const
+{
+    const int GifChunkSize = 4096;
+
+    while (!gifFormat->partialNewFrame) {
+        if (buffer.isEmpty()) {
+            buffer += device()->read(GifChunkSize);
+            if (buffer.isEmpty())
+                break;
+        }
+
+        int decoded = gifFormat->decode(&lastImage, (const uchar *)buffer.constData(), buffer.size(),
+                                        &nextDelay, &loopCnt);
+        if (decoded == -1)
+            break;
+        buffer.remove(0, decoded);
+    }
+    return gifFormat->partialNewFrame;
+}
+
+bool QGifHandler::canRead() const
+{
+    if (canRead(device()) || imageIsComing()) {
+        setFormat("gif");
+        return true;
+    }
+
+    return false;
+}
+
+bool QGifHandler::canRead(QIODevice *device)
+{
+    if (!device) {
+        qWarning("QGifHandler::canRead() called with no device");
+        return false;
+    }
+
+    char head[6];
+    if (device->peek(head, sizeof(head)) == sizeof(head))
+        return qstrncmp(head, "GIF87a", 6) == 0
+            || qstrncmp(head, "GIF89a", 6) == 0;
+    return false;
+}
+
+bool QGifHandler::read(QImage *image)
+{
+    const int GifChunkSize = 4096;
+
+    while (!gifFormat->newFrame) {
+        if (buffer.isEmpty()) {
+            buffer += device()->read(GifChunkSize);
+            if (buffer.isEmpty())
+                break;
+        }
+
+        int decoded = gifFormat->decode(&lastImage, (const uchar *)buffer.constData(), buffer.size(),
+                                        &nextDelay, &loopCnt);
+        if (decoded == -1)
+            break;
+        buffer.remove(0, decoded);
+    }
+    if (gifFormat->newFrame || (gifFormat->partialNewFrame && device()->atEnd())) {
+        *image = lastImage;
+        ++frameNumber;
+        gifFormat->newFrame = false;
+        gifFormat->partialNewFrame = false;
+        return true;
+    }
+
+    return false;
+}
+
+bool QGifHandler::write(const QImage &image)
+{
+    Q_UNUSED(image);
+    return false;
+}
+
+bool QGifHandler::supportsOption(ImageOption option) const
+{
+    if (!device() || device()->isSequential())
+        return option == Animation;
+    else
+        return option == Size
+            || option == Animation;
+}
+
+QVariant QGifHandler::option(ImageOption option) const
+{
+    if (option == Size) {
+        if (!scanIsCached) {
+            QGIFFormat::scan(device(), &imageSizes, &loopCnt);
+            scanIsCached = true;
+        }
+        // before the first frame is read, or we have an empty data stream
+        if (frameNumber == -1)
+            return (imageSizes.count() > 0) ? QVariant(imageSizes.at(0)) : QVariant();
+        // after the last frame has been read, the next size is undefined
+        if (frameNumber >= imageSizes.count() - 1)
+            return QVariant();
+        // and the last case: the size of the next frame
+        return imageSizes.at(frameNumber + 1);
+    } else if (option == Animation) {
+        return true;
+    }
+    return QVariant();
+}
+
+void QGifHandler::setOption(ImageOption option, const QVariant &value)
+{
+    Q_UNUSED(option);
+    Q_UNUSED(value);
+}
+
+int QGifHandler::nextImageDelay() const
+{
+    return nextDelay;
+}
+
+int QGifHandler::imageCount() const
+{
+    if (!scanIsCached) {
+        QGIFFormat::scan(device(), &imageSizes, &loopCnt);
+        scanIsCached = true;
+    }
+    return imageSizes.count();
+}
+
+int QGifHandler::loopCount() const
+{
+    if (!scanIsCached) {
+        QGIFFormat::scan(device(), &imageSizes, &loopCnt);
+        scanIsCached = true;
+    }
+
+    if (loopCnt == 0)
+        return -1;
+    else if (loopCnt == -1)
+        return 0;
+    else
+        return loopCnt;
+}
+
+int QGifHandler::currentImageNumber() const
+{
+    return frameNumber;
+}
+
+QByteArray QGifHandler::name() const
+{
+    return "gif";
+}
+
+QT_END_NAMESPACE