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91c256095f
Larger buffers improve performance significantly when streaming large quantity of data on very fast devices.
91 lines
2.2 KiB
C++
91 lines
2.2 KiB
C++
//
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// FileStream_WIN32.h
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//
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// Library: Foundation
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// Package: Streams
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// Module: FileStream
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//
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// Definition of the FileStreamBuf, FileInputStream and FileOutputStream classes.
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//
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// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// SPDX-License-Identifier: BSL-1.0
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//
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#ifndef Foundation_FileStream_WIN32_INCLUDED
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#define Foundation_FileStream_WIN32_INCLUDED
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#include "Poco/Foundation.h"
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#include "Poco/BufferedBidirectionalStreamBuf.h"
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#include "Poco/UnWindows.h"
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namespace Poco {
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class Foundation_API FileStreamBuf: public BufferedBidirectionalStreamBuf
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/// This stream buffer handles Fileio
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{
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public:
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using NativeHandle = HANDLE;
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FileStreamBuf();
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/// Creates a FileStreamBuf.
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~FileStreamBuf();
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/// Destroys the FileStream.
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void open(const std::string& path, std::ios::openmode mode);
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/// Opens the given file in the given mode.
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void openHandle(NativeHandle handle, std::ios::openmode mode);
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/// Take ownership of the given HANDLE.
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bool close();
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/// Closes the File stream buffer. Returns true if successful,
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/// false otherwise.
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bool resizeBuffer(std::streamsize bufferSize) override;
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/// Resizes internal buffer. Minimum size is BUFFER_SIZE.
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/// Minimum is used when requested size is smaller.
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/// Buffer can be resized only when the file is not open.
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/// Returns true if resize succeeded.
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std::streampos seekoff(std::streamoff off, std::ios::seekdir dir, std::ios::openmode mode = std::ios::in | std::ios::out) override;
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/// change position by offset, according to way and mode
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std::streampos seekpos(std::streampos pos, std::ios::openmode mode = std::ios::in | std::ios::out) override;
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/// change to specified position, according to mode
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void flushToDisk();
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/// Forces buffered data to be written to the disk
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NativeHandle nativeHandle() const;
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/// Returns native file descriptor handle
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Poco::UInt64 size() const;
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/// Returns file size
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protected:
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enum
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{
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BUFFER_SIZE = 4096
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};
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int readFromDevice(char* buffer, std::streamsize length) override;
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int writeToDevice(const char* buffer, std::streamsize length) override;
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private:
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std::string _path;
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NativeHandle _handle;
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UInt64 _pos {0};
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};
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} // namespace Poco
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#endif // Foundation_FileStream_WIN32_INCLUDED
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