qsvgtinydocument.cpp File Reference

#include "qsvgtinydocument_p.h"
#include "qsvghandler_p.h"
#include "qsvgfont_p.h"
#include "qpainter.h"
#include "qfile.h"
#include "qbuffer.h"
#include "qbytearray.h"
#include "qqueue.h"
#include "qstack.h"
#include "qdebug.h"
#include <zlib.h>

Go to the source code of this file.

Functions
static QByteArray	qt_inflateGZipDataFrom (QIODevice *device)

Function Documentation

qt_inflateGZipDataFrom()

QByteArray qt_inflateGZipDataFrom ( QIODevice *  device )

static

Definition at line 84 of file qsvgtinydocument.cpp.

Referenced by QSvgTinyDocument::load(), and QSvgTinyDocument::~QSvgTinyDocument().

{
    if (!device)
        return QByteArray();

    if (!device->isOpen())
        device->open(QIODevice::ReadOnly);

    Q_ASSERT(device->isOpen() && device->isReadable());

    static const int CHUNK_SIZE = 4096;
    int zlibResult = Z_OK;

    QByteArray source;
    QByteArray destination;

    // Initialize zlib stream struct
    z_stream zlibStream;
    zlibStream.next_in = Z_NULL;
    zlibStream.avail_in = 0;
    zlibStream.avail_out = 0;
    zlibStream.zalloc = Z_NULL;
    zlibStream.zfree = Z_NULL;
    zlibStream.opaque = Z_NULL;

    // Adding 16 to the window size gives us gzip decoding
    if (inflateInit2(&zlibStream, MAX_WBITS + 16) != Z_OK) {
        qWarning("Cannot initialize zlib, because: %s",
                (zlibStream.msg != NULL ? zlibStream.msg : "Unknown error"));
        return QByteArray();
    }

    bool stillMoreWorkToDo = true;
    while (stillMoreWorkToDo) {

        if (!zlibStream.avail_in) {
            source = device->read(CHUNK_SIZE);

            if (source.isEmpty())
                break;

            zlibStream.avail_in = source.size();
            zlibStream.next_in = reinterpret_cast<Bytef*>(source.data());
        }

        do {
            // Prepare the destination buffer
            int oldSize = destination.size();
            destination.resize(oldSize + CHUNK_SIZE);
            zlibStream.next_out = reinterpret_cast<Bytef*>(
                    destination.data() + oldSize - zlibStream.avail_out);
            zlibStream.avail_out += CHUNK_SIZE;

            zlibResult = inflate(&zlibStream, Z_NO_FLUSH);
            switch (zlibResult) {
                case Z_NEED_DICT:
                case Z_DATA_ERROR:
                case Z_STREAM_ERROR:
                case Z_MEM_ERROR: {
                    inflateEnd(&zlibStream);
                    qWarning("Error while inflating gzip file: %s",
                            (zlibStream.msg != NULL ? zlibStream.msg : "Unknown error"));
                    destination.chop(zlibStream.avail_out);
                    return destination;
                }
            }

        // If the output buffer still has more room after calling inflate
        // it means we have to provide more data, so exit the loop here
        } while (!zlibStream.avail_out);

        if (zlibResult == Z_STREAM_END) {
            // Make sure there are no more members to process before exiting
            if (!(zlibStream.avail_in && inflateReset(&zlibStream) == Z_OK))
                stillMoreWorkToDo = false;
        }
    }

    // Chop off trailing space in the buffer
    destination.chop(zlibStream.avail_out);

    inflateEnd(&zlibStream);
    return destination;
}