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

   This file is part of the juce_core module of the JUCE library.
   Copyright (c) 2015 - ROLI 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 juce_core module!
   All other JUCE 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.juce.com

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

#if JUCE_MSVC
 #pragma warning (push)
 #pragma warning (disable: 4309 4305 4365)
#endif

namespace zlibNamespace
{
 #if JUCE_INCLUDE_ZLIB_CODE
  #if JUCE_CLANG
   #pragma clang diagnostic push
   #pragma clang diagnostic ignored "-Wconversion"
   #pragma clang diagnostic ignored "-Wshadow"
   #pragma clang diagnostic ignored "-Wdeprecated-register"
  #endif

  #undef OS_CODE
  #undef fdopen
  #define ZLIB_INTERNAL
  #define NO_DUMMY_DECL
  #include "zlib/zlib.h"
  #include "zlib/adler32.c"
  #include "zlib/compress.c"
  #undef DO1
  #undef DO8
  #include "zlib/crc32.c"
  #include "zlib/deflate.c"
  #include "zlib/inffast.c"
  #undef PULLBYTE
  #undef LOAD
  #undef RESTORE
  #undef INITBITS
  #undef NEEDBITS
  #undef DROPBITS
  #undef BYTEBITS
  #include "zlib/inflate.c"
  #include "zlib/inftrees.c"
  #include "zlib/trees.c"
  #include "zlib/zutil.c"
  #undef Byte
  #undef fdopen
  #undef local
  #undef Freq
  #undef Code
  #undef Dad
  #undef Len

  #if JUCE_CLANG
   #pragma clang diagnostic pop
  #endif
 #else
  #include JUCE_ZLIB_INCLUDE_PATH
  #define z_uInt uInt
 #endif
}

#if JUCE_MSVC
 #pragma warning (pop)
#endif

//==============================================================================
// internal helper object that holds the zlib structures so they don't have to be
// included publicly.
class GZIPDecompressorInputStream::GZIPDecompressHelper
{
public:
    GZIPDecompressHelper (Format f)
        : finished (true),
          needsDictionary (false),
          error (true),
          streamIsValid (false),
          data (nullptr),
          dataSize (0)
    {
        using namespace zlibNamespace;
        zerostruct (stream);
        streamIsValid = (inflateInit2 (&stream, getBitsForFormat (f)) == Z_OK);
        finished = error = ! streamIsValid;
    }

    ~GZIPDecompressHelper()
    {
        using namespace zlibNamespace;
        if (streamIsValid)
            inflateEnd (&stream);
    }

    bool needsInput() const noexcept        { return dataSize <= 0; }

    void setInput (uint8* const data_, const size_t size) noexcept
    {
        data = data_;
        dataSize = size;
    }

    int doNextBlock (uint8* const dest, const unsigned int destSize)
    {
        using namespace zlibNamespace;
        if (streamIsValid && data != nullptr && ! finished)
        {
            stream.next_in  = data;
            stream.next_out = dest;
            stream.avail_in  = (z_uInt) dataSize;
            stream.avail_out = (z_uInt) destSize;

            switch (inflate (&stream, Z_PARTIAL_FLUSH))
            {
            case Z_STREAM_END:
                finished = true;
                // deliberate fall-through
            case Z_OK:
                data += dataSize - stream.avail_in;
                dataSize = (z_uInt) stream.avail_in;
                return (int) (destSize - stream.avail_out);

            case Z_NEED_DICT:
                needsDictionary = true;
                data += dataSize - stream.avail_in;
                dataSize = (size_t) stream.avail_in;
                break;

            case Z_DATA_ERROR:
            case Z_MEM_ERROR:
                error = true;

            default:
                break;
            }
        }

        return 0;
    }

    static int getBitsForFormat (Format f) noexcept
    {
        switch (f)
        {
            case zlibFormat:     return  MAX_WBITS;
            case deflateFormat:  return -MAX_WBITS;
            case gzipFormat:     return  MAX_WBITS | 16;
            default:             jassertfalse; break;
        }

        return MAX_WBITS;
    }

    bool finished, needsDictionary, error, streamIsValid;

    enum { gzipDecompBufferSize = 32768 };

private:
    zlibNamespace::z_stream stream;
    uint8* data;
    size_t dataSize;

    JUCE_DECLARE_NON_COPYABLE (GZIPDecompressHelper)
};

//==============================================================================
GZIPDecompressorInputStream::GZIPDecompressorInputStream (InputStream* source, bool deleteSourceWhenDestroyed,
                                                          Format f, int64 uncompressedLength)
  : sourceStream (source, deleteSourceWhenDestroyed),
    uncompressedStreamLength (uncompressedLength),
    format (f),
    isEof (false),
    activeBufferSize (0),
    originalSourcePos (source->getPosition()),
    currentPos (0),
    buffer ((size_t) GZIPDecompressHelper::gzipDecompBufferSize),
    helper (new GZIPDecompressHelper (f))
{
}

GZIPDecompressorInputStream::GZIPDecompressorInputStream (InputStream& source)
  : sourceStream (&source, false),
    uncompressedStreamLength (-1),
    format (zlibFormat),
    isEof (false),
    activeBufferSize (0),
    originalSourcePos (source.getPosition()),
    currentPos (0),
    buffer ((size_t) GZIPDecompressHelper::gzipDecompBufferSize),
    helper (new GZIPDecompressHelper (zlibFormat))
{
}

GZIPDecompressorInputStream::~GZIPDecompressorInputStream()
{
}

int64 GZIPDecompressorInputStream::getTotalLength()
{
    return uncompressedStreamLength;
}

int GZIPDecompressorInputStream::read (void* destBuffer, int howMany)
{
    jassert (destBuffer != nullptr && howMany >= 0);

    if (howMany > 0 && ! isEof)
    {
        int numRead = 0;
        uint8* d = static_cast<uint8*> (destBuffer);

        while (! helper->error)
        {
            const int n = helper->doNextBlock (d, (unsigned int) howMany);
            currentPos += n;

            if (n == 0)
            {
                if (helper->finished || helper->needsDictionary)
                {
                    isEof = true;
                    return numRead;
                }

                if (helper->needsInput())
                {
                    activeBufferSize = sourceStream->read (buffer, (int) GZIPDecompressHelper::gzipDecompBufferSize);

                    if (activeBufferSize > 0)
                    {
                        helper->setInput (buffer, (size_t) activeBufferSize);
                    }
                    else
                    {
                        isEof = true;
                        return numRead;
                    }
                }
            }
            else
            {
                numRead += n;
                howMany -= n;
                d += n;

                if (howMany <= 0)
                    return numRead;
            }
        }
    }

    return 0;
}

bool GZIPDecompressorInputStream::isExhausted()
{
    return helper->error || isEof;
}

int64 GZIPDecompressorInputStream::getPosition()
{
    return currentPos;
}

bool GZIPDecompressorInputStream::setPosition (int64 newPos)
{
    if (newPos < currentPos)
    {
        // to go backwards, reset the stream and start again..
        isEof = false;
        activeBufferSize = 0;
        currentPos = 0;
        helper = new GZIPDecompressHelper (format);

        sourceStream->setPosition (originalSourcePos);
    }

    skipNextBytes (newPos - currentPos);
    return true;
}