/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/*

 * This file is part of the libcdr project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 */

#include "CDRInternalStream.h"

#include <zlib.h>

#include <string.h>  // for memcpy

#define CHUNK 16384

libcdr::CDRInternalStream::CDRInternalStream(const std::vector<unsigned char> &buffer) :

  librevenge::RVNGInputStream(),

  m_offset(0),

  m_buffer(buffer)

{

}

libcdr::CDRInternalStream::CDRInternalStream(librevenge::RVNGInputStream *input, unsigned long size, bool compressed) :

  librevenge::RVNGInputStream(),

  m_offset(0),

  m_buffer()

{

  if (!size)

    return;

  if (!compressed)

  {

    unsigned long tmpNumBytesRead = 0;

    const unsigned char *tmpBuffer = input->read(size, tmpNumBytesRead);

    if (size != tmpNumBytesRead)

      return;

    m_buffer = std::vector<unsigned char>(size);

    memcpy(&m_buffer[0], tmpBuffer, size);

  }

  else

  {

    int ret;

    z_stream strm;

    unsigned char out[CHUNK];

    /* allocate inflate state */

    strm.zalloc = Z_NULL;

    strm.zfree = Z_NULL;

    strm.opaque = Z_NULL;

    strm.avail_in = 0;

    strm.next_in = Z_NULL;

    ret = inflateInit(&strm);

    if (ret != Z_OK)

      return;

    unsigned long tmpNumBytesRead = 0;

    const unsigned char *tmpBuffer = input->read(size, tmpNumBytesRead);

    if (size != tmpNumBytesRead)

    {

      (void)inflateEnd(&strm);

      return;

    }

    strm.avail_in = (uInt)tmpNumBytesRead;

    strm.next_in = const_cast<Bytef *>(tmpBuffer);

    do

    {

      strm.avail_out = CHUNK;

      strm.next_out = out;

      ret = inflate(&strm, Z_NO_FLUSH);

      switch (ret)

      {

      case Z_NEED_DICT:

      case Z_DATA_ERROR:

      case Z_MEM_ERROR:

        (void)inflateEnd(&strm);

        m_buffer.clear();

        return;

      default:

        break;

      }

      unsigned have = CHUNK - strm.avail_out;

      for (unsigned long i=0; i<have; i++)

        m_buffer.push_back(out[i]);

    }

    while (strm.avail_out == 0);

    (void)inflateEnd(&strm);

  }

}

const unsigned char *libcdr::CDRInternalStream::read(unsigned long numBytes, unsigned long &numBytesRead)

{

  numBytesRead = 0;

  if (numBytes == 0)

    return nullptr;

  if (m_offset < 0)

    return nullptr;

  const unsigned long bufSize = m_buffer.size();

  const unsigned long pos = static_cast<unsigned long>(m_offset);

  const unsigned long remaining = pos < bufSize ? bufSize - pos : 0;

  const unsigned long numBytesToRead = numBytes < remaining ? numBytes : remaining;

  numBytesRead = numBytesToRead; // about as paranoid as we can be..

  if (numBytesToRead == 0)

    return nullptr;

  long oldOffset = m_offset;

  m_offset += numBytesToRead;

  return &m_buffer[oldOffset];

}

int libcdr::CDRInternalStream::seek(long offset, librevenge::RVNG_SEEK_TYPE seekType)

{

  if (seekType == librevenge::RVNG_SEEK_CUR)

    m_offset += offset;

  else if (seekType == librevenge::RVNG_SEEK_SET)

    m_offset = offset;

  else if (seekType == librevenge::RVNG_SEEK_END)

    m_offset = long(static_cast<unsigned long>(m_buffer.size())) + offset;

  if (m_offset < 0)

  {

    m_offset = 0;

    return 1;

  }

  if ((long)m_offset > (long)m_buffer.size())

  {

    m_offset = m_buffer.size();

    return 1;

  }

  return 0;

}

long libcdr::CDRInternalStream::tell()

{

  return m_offset;

}

bool libcdr::CDRInternalStream::isEnd()

{

  if ((long)m_offset >= (long)m_buffer.size())

    return true;

  return false;

}

/* vim:set shiftwidth=2 softtabstop=2 expandtab: */