MemoryFile.cpp

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/*  Visualization Library                                                             */
/*  http://visualizationlibrary.org                                                   */
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/*  Copyright (c) 2005-2020, Michele Bosi                                             */
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#include <vlCore/MemoryFile.hpp>
#include <vlCore/Log.hpp>

using namespace vl;

//---------------------------------------------------------------------------
// MemoryFile
//---------------------------------------------------------------------------
MemoryFile::MemoryFile()
{
  mBuffer = new Buffer;
  mPtr = 0;
  mIsOpen = false;
}
//---------------------------------------------------------------------------
bool MemoryFile::open(EOpenMode mode)
{
  if ( isOpen() )
  {
    Log::error("MemoryFile::open(): file already open.\n");
    return false;
  }

  // for now support only OM_ReadOnly mode
  mIsOpen = (mode == OM_ReadOnly);
  return mIsOpen;
}
//---------------------------------------------------------------------------
void MemoryFile::copy(VirtualFile* file)
{
  if (file->isOpen())
    file->close();

  allocateBuffer(file->size());

  file->open(OM_ReadOnly);

  file->read( ptr(), size() );

  file->close();
}
//---------------------------------------------------------------------------
long long MemoryFile::position_Implementation() const
{
  if (!isOpen())
    return -1;
  return mPtr;
}
//---------------------------------------------------------------------------
long long MemoryFile::read_Implementation(void* buffer, long long byte_count)
{
  if (!isOpen())
    return 0;
  if ( mBuffer->bytesUsed() )
  {
    long long bytes_left = mBuffer->bytesUsed() - mPtr;
    byte_count = byte_count < bytes_left ? byte_count : bytes_left;
    memcpy(buffer, ptr() + mPtr, (size_t)byte_count);
    mPtr += byte_count;
    return byte_count;
  }
  else
  {
    // no error is generated for an empty memory stream
    return 0;
  }
}
//---------------------------------------------------------------------------
bool MemoryFile::seekSet_Implementation(long long offset)
{
  if (!isOpen())
    return false;
  mPtr = offset;
  if (mPtr < 0) mPtr = 0;
  if (mPtr > static_cast<long long>(mBuffer->bytesUsed()))
      mPtr = mBuffer->bytesUsed();
  return true;
}
//-----------------------------------------------------------------------------
ref<VirtualFile> MemoryFile::clone() const
{
  ref<MemoryFile> file = new MemoryFile;
  file->operator=(*this);
  return file;
}
//---------------------------------------------------------------------------