/* -*- Mode: C++; c-default-style: "k&r"; indent-tabs-mode: nil; tab-width: 2; c-basic-offset: 2 -*- */

/* libmwaw: tools

* Version: MPL 2.0 / LGPLv2+

*

* The contents of this file are subject to the Mozilla Public License Version

* 2.0 (the "License"); you may not use this file except in compliance with

* the License or as specified alternatively below. You may obtain a copy of

* the License at http://www.mozilla.org/MPL/

*

* Software distributed under the License is distributed on an "AS IS" basis,

* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License

* for the specific language governing rights and limitations under the

* License.

*

* Major Contributor(s):

* Copyright (C) 2011, 2012 Alonso Laurent (alonso@loria.fr)

*

*

* All Rights Reserved.

*

* For minor contributions see the git repository.

*

* Alternatively, the contents of this file may be used under the terms of

* the GNU Lesser General Public License Version 2 or later (the "LGPLv2+"),

* in which case the provisions of the LGPLv2+ are applicable

* instead of those above.

*/

#include <string.h>

#include <iostream>

#include "file_internal.h"

#include "input.h"

namespace libmwaw_tools

{

//

// InputStream

//

InputStream::~InputStream()

{

}

unsigned char InputStream::readU8()

{

  unsigned long nRead;

  unsigned char const *data = read(1, nRead);

  if (!data || nRead != 1) return 0;

  return data[0];

}

unsigned short InputStream::readU16()

{

  unsigned long nRead;

  unsigned char const *data = read(2, nRead);

  if (!data || nRead != 2) return 0;

  return static_cast<unsigned short>((data[0]<<8)+data[1]);

}

unsigned int InputStream::readU32()

{

  unsigned long nRead;

  unsigned char const *data = read(4, nRead);

  if (!data || nRead != 4) return 0;

  return static_cast<unsigned int>((data[0]<<24)+(data[1]<<16)+(data[2]<<8)+data[3]);

}

char InputStream::read8()

{

  unsigned long nRead;

  unsigned char const *data = read(1, nRead);

  if (!data || nRead != 1) return 0;

  return static_cast<char>(data[0]);

}

short InputStream::read16()

{

  unsigned long nRead;

  unsigned char const *data = read(2, nRead);

  if (!data || nRead != 2) return 0;

  return static_cast<short>((data[0]<<8)+data[1]);

}

int InputStream::read32()

{

  unsigned long nRead;

  unsigned char const *data = read(4, nRead);

  if (!data || nRead != 4) return 0;

  return static_cast<int>((data[0]<<24)+(data[1]<<16)+(data[2]<<8)+data[3]);

}

int InputStream::seek(long _offset, SeekType seekType)

{

  long sz = length();

  if (seekType == SK_CUR)

    m_offset += _offset;

  else if (seekType == SK_SET)

    m_offset = _offset;

  else if (seekType == SK_END)

    m_offset = sz+_offset;

  if (m_offset < 0) {

    m_offset = 0;

    return 1;

  }

  if (m_offset > sz) {

    m_offset = sz;

    return 1;

  }

  return 0;

}

//

// StringStream

//

StringStream::StringStream(const unsigned char *data, const unsigned long dataSize)

  : InputStream()

  , m_buffer(dataSize)

{

  memcpy(&m_buffer[0], data, dataSize);

}

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

{

  numBytesRead = 0;

  if (numBytes == 0)

    return 0;

  unsigned long numBytesToRead;

  if ((static_cast<unsigned long>(m_offset)+numBytes) < m_buffer.size())

    numBytesToRead = numBytes;

  else

    numBytesToRead = static_cast<unsigned long>(static_cast<long>(m_buffer.size()) - m_offset);

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

  if (numBytesToRead == 0)

    return 0;

  long oldOffset = m_offset;

  m_offset += numBytesToRead;

  return &m_buffer[size_t(oldOffset)];

}

//

// FileStream

//

FileStream::FileStream(char const *path)

  : InputStream()

  , m_file(0)

  , m_isOk(true)

  , m_buffer()

  , m_bufferPos(0)

{

  m_file = fopen(path,"r");

  if (m_file)

    return;

#ifdef DEBUG

  std::cerr << "FileStream:FileStream can not open " << path << "\n";

#endif

  m_isOk = false;

}

FileStream::~FileStream()

{

  if (!m_isOk) return;

  if (m_file) fclose(m_file);

}

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

{

  numBytesRead = 0;

  if (!m_isOk || !m_file)

    return 0;

  long lastPos = m_offset+long(numBytes);

  long fileLength = length();

  if (lastPos > fileLength) lastPos = fileLength;

  // check if the buffer is or not ok

  auto bufSize = long(m_buffer.size());

  if (m_offset < m_bufferPos || lastPos > m_bufferPos+bufSize) {

    auto numToRead = size_t(numBytes);

    if (numToRead < 4096 && m_offset+4096 <= fileLength)

      numToRead = 4096;

    else if (numToRead < 4096)

      numToRead = size_t(fileLength-m_offset);

    if (numToRead==0)

      return 0;

    // try to read numToRead bytes

    m_bufferPos = m_offset;

    m_buffer.resize(size_t(numToRead));

#if 0

    MWAW_DEBUG_MSG(("FileStream::read called with %ld[%ld]: read %ld bytes\n", m_offset, numBytes, numToRead));

#endif

    if (fseek(m_file, m_offset, SEEK_SET)==-1) {

      MWAW_DEBUG_MSG(("FileStream::read get error when doing a seek\n"));

      m_buffer.clear();

      return 0;

    }

    size_t nRead = fread(&(m_buffer[0]), 1, numToRead, m_file);

    if (nRead != numToRead) {

      MWAW_DEBUG_MSG(("FileStream::read get error when reading data\n"));

      m_buffer.resize(size_t(nRead));

    }

  }

  bufSize = long(m_buffer.size());

  if (!bufSize)

    return 0;

  numBytesRead = static_cast<unsigned long>(m_bufferPos + bufSize - m_offset);

  if (numBytesRead > numBytes)

    numBytesRead = numBytes;

  unsigned char const *res = &(m_buffer[size_t(m_offset-m_bufferPos)]);

  m_offset += long(numBytesRead);

  return res;

}

long FileStream::length()

{

  if (!m_isOk || !m_file) return 0;

  if (fseek(m_file, 0, SEEK_END)==-1) {

    MWAW_DEBUG_MSG(("FileStream::length get error when reading data\n"));

    return 0;

  }

  return long(ftell(m_file));

}

}

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