source: XMLIO_V2/external/src/POCO/Foundation/FileStream_WIN32.hpp @ 80

//
// 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