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FileStream_WIN32.cpp
//
// FileStream.cpp
//
// $Id: //poco/1.3/Foundation/src/FileStream_WIN32.cpp#5 $
//
// Library: Foundation
// Package: Streams
// Module:  FileStream
//
// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#include "Poco/FileStream.h"
#include "Poco/File.h"
#include "Poco/Exception.h"
#if defined (POCO_WIN32_UTF8)
#include "Poco/UnicodeConverter.h"
#endif


namespace Poco {


FileStreamBuf::FileStreamBuf():
      BufferedBidirectionalStreamBuf(BUFFER_SIZE, std::ios::in | std::ios::out),
      _handle(INVALID_HANDLE_VALUE),
      _pos(0)
{
}


FileStreamBuf::~FileStreamBuf()
{
      close();
}


void FileStreamBuf::open(const std::string& path, std::ios::openmode mode)
{
      poco_assert (_handle == INVALID_HANDLE_VALUE);

      _path = path;
      setMode(mode);

      DWORD access = 0;
      if (mode & std::ios::in)
            access |= GENERIC_READ;
      if (mode & std::ios::out)
            access |= GENERIC_WRITE;

      DWORD shareMode = FILE_SHARE_READ;
      if (!(mode & std::ios::out))
            shareMode |= FILE_SHARE_WRITE;
            
      DWORD creationDisp = OPEN_EXISTING;
      if (mode & std::ios::trunc)
            creationDisp = CREATE_ALWAYS;
      else if (mode & std::ios::out)
            creationDisp = OPEN_ALWAYS;

      DWORD flags = FILE_ATTRIBUTE_NORMAL;
      
#if defined (POCO_WIN32_UTF8)
      std::wstring utf16Path;
      UnicodeConverter::toUTF16(path, utf16Path);
      _handle = CreateFileW(utf16Path.c_str(), access, shareMode, NULL, creationDisp, flags, NULL);
#else
      _handle = CreateFileA(path.c_str(), access, shareMode, NULL, creationDisp, flags, NULL);
#endif

      if (_handle == INVALID_HANDLE_VALUE)
            File::handleLastError(_path);
            
      if ((mode & std::ios::ate) || (mode & std::ios::app))
            seekoff(0, std::ios::end, mode);
}


int FileStreamBuf::readFromDevice(char* buffer, std::streamsize length)
{
      if (INVALID_HANDLE_VALUE == _handle || !(getMode() & std::ios::in))
            return -1;

      if (getMode() & std::ios::out)
            sync();
      
      DWORD bytesRead(0);
      BOOL rc = ReadFile(_handle, buffer, static_cast<DWORD>(length), &bytesRead, NULL);
      if (rc == 0)
            File::handleLastError(_path);

      _pos += bytesRead;

      return static_cast<int>(bytesRead);
}


int FileStreamBuf::writeToDevice(const char* buffer, std::streamsize length)
{
      if (INVALID_HANDLE_VALUE == _handle || !(getMode() & std::ios::out))
            return -1;

      if (getMode() & std::ios::app)
      {
            LARGE_INTEGER li;
            li.QuadPart = 0;
            li.LowPart  = SetFilePointer(_handle, li.LowPart, &li.HighPart, FILE_END);
            if (li.LowPart == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR)
                  File::handleLastError(_path);
            _pos = li.QuadPart;
      }

      DWORD bytesWritten(0);
      BOOL rc = WriteFile(_handle, buffer, static_cast<DWORD>(length), &bytesWritten, NULL);
      if (rc == 0)
            File::handleLastError(_path);
            
      _pos += bytesWritten;

      return static_cast<int>(bytesWritten);
}


bool FileStreamBuf::close()
{
      bool success = true;
      if (_handle != INVALID_HANDLE_VALUE)
      {
            try
            {
                  if (getMode() & std::ios::out)
                        sync();
            }
            catch (...)
            {
                  success = false;
            }
            CloseHandle(_handle);
            _handle = INVALID_HANDLE_VALUE;
      }
      return success;
}


std::streampos FileStreamBuf::seekoff(std::streamoff off, std::ios::seekdir dir, std::ios::openmode mode)
{
      if (INVALID_HANDLE_VALUE == _handle || !(getMode() & mode))
            return -1;
      
      if (getMode() & std::ios::out)
            sync();

      std::streamoff adj;
      if (mode & std::ios::in)
            adj = static_cast<std::streamoff>(egptr() - gptr());
      else
            adj = 0;

      resetBuffers();

      DWORD offset = FILE_BEGIN;
      if (dir == std::ios::cur)
      {
            offset = FILE_CURRENT;
            off -= adj;
      }
      else if (dir == std::ios::end)
      {
            offset = FILE_END;
      }
      
      LARGE_INTEGER li;
      li.QuadPart = off;
      li.LowPart  = SetFilePointer(_handle, li.LowPart, &li.HighPart, offset);

      if (li.LowPart == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR)
            File::handleLastError(_path);
      _pos = li.QuadPart;
      return std::streampos(static_cast<std::streamoff>(_pos));
}


std::streampos FileStreamBuf::seekpos(std::streampos pos, std::ios::openmode mode)
{
      if (INVALID_HANDLE_VALUE == _handle || !(getMode() & mode))
            return -1;

      if (getMode() & std::ios::out)
            sync();

      resetBuffers();

      LARGE_INTEGER li;
      li.QuadPart = pos;
      li.LowPart  = SetFilePointer(_handle, li.LowPart, &li.HighPart, FILE_BEGIN);

      if (li.LowPart == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR)
            File::handleLastError(_path);
      _pos = li.QuadPart;
      return std::streampos(static_cast<std::streamoff>(_pos));
}


} // namespace Poco

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