filestream_win32.cpp.svn-base

很好用的网络封装库,不熟悉网络编程的人也可以使用。使用风格良好的标准c++编写。

//
// FileStream.cpp
//
// $Id: //poco/1.3/Foundation/src/FileStream_WIN32.cpp#1 $
//
// 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, 0),
	_handle(INVALID_HANDLE_VALUE),
	_pos(0)
{
}


FileStreamBuf::~FileStreamBuf()
{
	try
	{
		close();
	}
	catch (...)
	{
	}
}


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;
	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);
}


void FileStreamBuf::close()
{
	if (_handle != INVALID_HANDLE_VALUE)
	{
		if (getMode() & std::ios::out)
			sync();
			
		CloseHandle(_handle);
		_handle = INVALID_HANDLE_VALUE;
	}
}


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