rippled/modules/beast_core/zip/GZIPCompressorOutputStream.cpp

/*
  ==============================================================================

   This file is part of the beast_core module of the BEAST library.
   Copyright (c) 2013 - Raw Material Software Ltd.

   Permission to use, copy, modify, and/or distribute this software for any purpose with
   or without fee is hereby granted, provided that the above copyright notice and this
   permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN
   NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
   DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
   IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

   ------------------------------------------------------------------------------

   NOTE! This permissive ISC license applies ONLY to files within the beast_core module!
   All other BEAST modules are covered by a dual GPL/commercial license, so if you are
   using any other modules, be sure to check that you also comply with their license.

   For more details, visit www.beast.com

  ==============================================================================
*/

class GZIPCompressorOutputStream::GZIPCompressorHelper : public Uncopyable
{
public:
    GZIPCompressorHelper (const int compressionLevel, const int windowBits)
        : compLevel ((compressionLevel < 1 || compressionLevel > 9) ? -1 : compressionLevel),
          isFirstDeflate (true),
          streamIsValid (false),
          finished (false)
    {
        using namespace zlibNamespace;
        zerostruct (stream);

        streamIsValid = (deflateInit2 (&stream, compLevel, Z_DEFLATED,
                                       windowBits != 0 ? windowBits : MAX_WBITS,
                                       8, strategy) == Z_OK);
    }

    ~GZIPCompressorHelper()
    {
        if (streamIsValid)
            zlibNamespace::deflateEnd (&stream);
    }

    bool write (const uint8* data, size_t dataSize, OutputStream& out)
    {
        // When you call flush() on a gzip stream, the stream is closed, and you can
        // no longer continue to write data to it!
        bassert (! finished);

        while (dataSize > 0)
            if (! doNextBlock (data, dataSize, out, Z_NO_FLUSH))
                return false;

        return true;
    }

    void finish (OutputStream& out)
    {
        const uint8* data = nullptr;
        size_t dataSize = 0;

        while (! finished)
            doNextBlock (data, dataSize, out, Z_FINISH);
    }

private:
    enum { strategy = 0 };

    zlibNamespace::z_stream stream;
    const int compLevel;
    bool isFirstDeflate, streamIsValid, finished;
    zlibNamespace::Bytef buffer[32768];

    bool doNextBlock (const uint8*& data, size_t& dataSize, OutputStream& out, const int flushMode)
    {
        using namespace zlibNamespace;

        if (streamIsValid)
        {
            stream.next_in   = const_cast <uint8*> (data);
            stream.next_out  = buffer;
            stream.avail_in  = (z_uInt) dataSize;
            stream.avail_out = (z_uInt) sizeof (buffer);

            const int result = isFirstDeflate ? deflateParams (&stream, compLevel, strategy)
                                              : deflate (&stream, flushMode);
            isFirstDeflate = false;

            switch (result)
            {
                case Z_STREAM_END:
                    finished = true;
                    // Deliberate fall-through..
                case Z_OK:
                {
                    data += dataSize - stream.avail_in;
                    dataSize = stream.avail_in;
                    const ssize_t bytesDone = (ssize_t) sizeof (buffer) - (ssize_t) stream.avail_out;
                    return bytesDone <= 0 || out.write (buffer, (size_t) bytesDone);
                }

                default:
                    break;
            }
        }

        return false;
    }
};

//==============================================================================
GZIPCompressorOutputStream::GZIPCompressorOutputStream (OutputStream* const out,
                                                        const int compressionLevel,
                                                        const bool deleteDestStream,
                                                        const int windowBits)
    : destStream (out, deleteDestStream),
      helper (new GZIPCompressorHelper (compressionLevel, windowBits))
{
    bassert (out != nullptr);
}

GZIPCompressorOutputStream::~GZIPCompressorOutputStream()
{
    flush();
}

void GZIPCompressorOutputStream::flush()
{
    helper->finish (*destStream);
    destStream->flush();
}

bool GZIPCompressorOutputStream::write (const void* destBuffer, size_t howMany)
{
    bassert (destBuffer != nullptr && (ssize_t) howMany >= 0);

    return helper->write (static_cast <const uint8*> (destBuffer), howMany, *destStream);
}

int64 GZIPCompressorOutputStream::getPosition()
{
    return destStream->getPosition();
}

bool GZIPCompressorOutputStream::setPosition (int64 /*newPosition*/)
{
    bassertfalse; // can't do it!
    return false;
}

//==============================================================================

class GZIPTests : public UnitTest
{
public:
    GZIPTests()  : UnitTest ("GZIP", "beast") {}

    void runTest()
    {
        beginTestCase ("GZIP");
        Random rng;

        for (int i = 100; --i >= 0;)
        {
            MemoryOutputStream original, compressed, uncompressed;

            {
                GZIPCompressorOutputStream zipper (&compressed, rng.nextInt (10), false);

                for (int j = rng.nextInt (100); --j >= 0;)
                {
                    MemoryBlock data ((unsigned int) (rng.nextInt (2000) + 1));

                    for (int k = (int) data.getSize(); --k >= 0;)
                        data[k] = (char) rng.nextInt (255);

                    original << data;
                    zipper   << data;
                }
            }

            {
                MemoryInputStream compressedInput (compressed.getData(), compressed.getDataSize(), false);
                GZIPDecompressorInputStream unzipper (compressedInput);

                uncompressed << unzipper;
            }

            expectEquals ((int) uncompressed.getDataSize(),
                          (int) original.getDataSize());

            if (original.getDataSize() == uncompressed.getDataSize())
                expect (memcmp (uncompressed.getData(),
                                original.getData(),
                                original.getDataSize()) == 0);
        }
    }
};

static GZIPTests gzipTests;