78 lines
1.7 KiB
C++
78 lines
1.7 KiB
C++
#include "gzipdevice.h"
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#include <QFile>
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#include <stdexcept>
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GzipDevice::GzipDevice(QFile &file, QObject *parent) :
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QIODevice(parent),
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m_file(file)
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{
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if (!m_file.isOpen())
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throw std::runtime_error("file is not open");
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setOpenMode(QIODevice::ReadOnly);
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// Prepare inflater status
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strm.zalloc = Z_NULL;
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strm.zfree = Z_NULL;
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strm.opaque = Z_NULL;
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strm.avail_in = 0;
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strm.next_in = Z_NULL;
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// Initialize inflater
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m_result = inflateInit2(&strm, 15 + 16);
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if (m_result != Z_OK)
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throw std::runtime_error("could not init z_stream");
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}
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GzipDevice::~GzipDevice()
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{
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inflateEnd(&strm);
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}
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bool GzipDevice::isSequential() const
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{
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return true;
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}
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bool GzipDevice::atEnd() const
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{
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return m_result == Z_STREAM_END;
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}
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qint64 GzipDevice::readData(char *data, qint64 maxlen)
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{
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if (strm.avail_in == 0)
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{
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strm.next_in = reinterpret_cast<unsigned char *>(m_readBuffer);
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strm.avail_in = m_file.read(m_readBuffer, m_readBufferSize);
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}
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strm.next_out = reinterpret_cast<unsigned char*>(data);
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strm.avail_out = maxlen;
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m_result = inflate(&strm, Z_NO_FLUSH);
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switch (m_result) {
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case Z_NEED_DICT:
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throw std::runtime_error("decompression failed: Z_NEED_DICT");
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case Z_DATA_ERROR:
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throw std::runtime_error("decompression failed: Z_DATA_ERROR");
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case Z_MEM_ERROR:
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throw std::runtime_error("decompression failed: Z_MEM_ERROR");
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case Z_STREAM_ERROR:
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throw std::runtime_error("decompression failed: Z_STREAM_ERROR");
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}
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return maxlen-strm.avail_out;
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}
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qint64 GzipDevice::writeData(const char *data, qint64 len)
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{
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Q_UNUSED(data)
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Q_UNUSED(len)
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throw std::runtime_error("writing not allowed!");
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return -1;
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}
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