other-licenses/7zstub/src/7zip/Common/OffsetStream.cpp

   1 // OffsetStream.cpp
   2
   3 #include "StdAfx.h"
   4
   5 #include "Common/Defs.h"
   6 #include "OffsetStream.h"
   7
   8 HRESULT COffsetOutStream::Init(IOutStream *stream, UInt64 offset)
   9 {
  10   _offset = offset;
  11   _stream = stream;
  12   return _stream->Seek(offset, STREAM_SEEK_SET, NULL);
  13 }
  14
  15 STDMETHODIMP COffsetOutStream::Write(const void *data, UInt32 size, UInt32 *processedSize)
  16 {
  17   return _stream->Write(data, size, processedSize);
  18 }
  19
  20 STDMETHODIMP COffsetOutStream::Seek(Int64 offset, UInt32 seekOrigin,
  21     UInt64 *newPosition)
  22 {
  23   UInt64 absoluteNewPosition;
  24   if (seekOrigin == STREAM_SEEK_SET)
  25     offset += _offset;
  26   HRESULT result = _stream->Seek(offset, seekOrigin, &absoluteNewPosition);
  27   if (newPosition != NULL)
  28     *newPosition = absoluteNewPosition - _offset;
  29   return result;
  30 }
  31
  32 STDMETHODIMP COffsetOutStream::SetSize(Int64 newSize)
  33 {
  34   return _stream->SetSize(_offset + newSize);
  35 }