core/Common/FileWriter.h

#pragma once

#include "./DocxFormat/Source/SystemUtility/File.h"

namespace NFileWriter
{
	//------------------------------------------------------------------------------------------------------
	// CBufferedFileWriter
	//------------------------------------------------------------------------------------------------------
	// Àáñòðàêòíûé êëàññ, êîòîðûé ñîäåðæèò â ñåáå îáúÿâëåíèÿ ôóíêöèé
	//------------------------------------------------------------------------------------------------------

	class CFileWriter
	{
	public :

		// Ïðèíèìàåò äàííûå íà çàïèñü
		virtual void Write ( BYTE* lpData, LONG64 lDataLength ) = 0;
		// Ôëàø ( äîïèñûâàåì âñå äàííûå )
		virtual void Flush () = 0;
		// Ñèê íà óêàçàííóþ ïîçèöèþ ïî ôàéëó
                virtual void Seek ( LONG64 lPosition, DWORD dwFrom = 0 ) = 0;
		// Òåêóùàÿ ïîçèöèÿ 
                virtual void GetPosition(ULONG64& nPos) = 0;
		// Ðàçìåð çàïèñàííîãî ôàéëà
                virtual void GetSize(ULONG64& nLen) = 0;

	public :

		// Êîíñòðóêòîð
		CFileWriter ()
		{
		}
		// Âèðòóàëüíûé äåñòðóêòîð
		virtual ~CFileWriter ()
		{
		}
	};

	//------------------------------------------------------------------------------------------------------
	// CBufferedFileWriter
	//------------------------------------------------------------------------------------------------------
	// Êëàññ, êîòîðûé çàíèìàåòñÿ çàïèñüþ ôàéëà íà äèñê
	//------------------------------------------------------------------------------------------------------

	class CBufferedFileWriter : public CFileWriter
	{
	private :

		CFile m_oFile;
		//HANDLE m_hFile;									// Õåíäë íà ôàéë, â êîòîðûé èäåò çàïèñü

		LONG64 m_lBufferSize;							// Ðàçìåð áóôôåðà

		BYTE* m_lpBuffer;								// Ñàì áóôôåð

		LONG64 m_lWritePointer;							// Ïîçèöèÿ äëÿ çàïèñè äàííûõ â áóôôåð

	public :

		// Êîíñòðóêòîð ( îò èìåíè ôàéëà, ñàì êîíòðîë îòêðûâàåò ôàéë )
		CBufferedFileWriter ( CString & sFileName, LONG64 lBufferSize = 10 * 1024 * 1024 ) : CFileWriter ()
		{
			if (m_oFile.CreateFile(sFileName) != S_OK)
			// Åñëè íå ïîëó÷èëîñü îòêðûòü ôàéë
			{
				// Âûäàåì èñêëþ÷åíèå
				throw 1;
			}

			// Êîïèðóåì äàííûå
			m_lBufferSize		= lBufferSize;

			// Îáíóëÿåì ïåðåìåííûå
			m_lWritePointer		= 0;

			// Âûäåëÿåì áóôåð.
			m_lpBuffer = ( BYTE* ) new BYTE[ m_lBufferSize ];

			// Åñëè áóôôåð íå âûäåëèëñÿ, âîçâðàùàåì Exception
			if ( !m_lpBuffer )
			{
				// Âûäàåì èñêëþ÷åíèå
				throw 1;
			}

			// Âñå îòëè÷íî!!!
		}

		// Äåñòðóêòîð
		virtual ~CBufferedFileWriter ()
		{
			Flush();
			m_oFile.CloseFile();

			// Óäàëÿåì áóôôåð
			RELEASEARRAYOBJECTS(m_lpBuffer);
		}
		// Ïðèíèìàåò äàííûå íà çàïèñü
		virtual void Write ( BYTE* lpData, LONG64 lDataLength )
		{
			// Ïîêà ðàçìåð äàííûõ íå èñ÷åðïàí
			while ( 0 < lDataLength )
			{
				// Ðàçìåð ñâîáîäíîé ïàìÿòè â áóôôåðå
				LONG64 lBufferFreeLength = 0;

				// Öèêë, ïîêà íå ïîÿâèòñÿ ñâîáîäíîå ìåñòî äëÿ çàïèñè
				while ( 0 >= ( lBufferFreeLength = m_lBufferSize - m_lWritePointer ) )
				{
					// Ïèøåì äàííûå, åñëè íå ïîëó÷èëîñü, òî ãåíåðèðóåì èñêëþ÷åíèå
                                        if ( false == WriteBuffer ( m_lBufferSize ) )
						throw 1;
				}

				// Ïðîâåðÿåì äîñòàòî÷íî ëè ìåñòà, ÷òîáû çàïèñàòü âåñü ïðèøåäøèé áóôåð â ïàìÿòü
				if ( lBufferFreeLength > lDataLength )
					lBufferFreeLength = lDataLength;

				// Êîïèðóåì äàííûå â áóôôåð
				memcpy ( m_lpBuffer + m_lWritePointer, lpData, (size_t) lBufferFreeLength);

				// Óìåíüøàåì ðàçìåð äàííûõ ðîâíî íà ñòîëüêî, ñêîëüêî çàïèñàëè â áóôôåð
				lDataLength -= lBufferFreeLength;
				// Ñäâèãàåì óêàçàòåëü íà ïðèøåäøèå äàííûå
				lpData = lpData + lBufferFreeLength;
				// Ñäâèãàåì ïîçèöèþ äëÿ çàïèñè äàííûõ â áóôôåð
				m_lWritePointer += lBufferFreeLength;
			}
		}
		// Ôëàø ( äîïèñûâàåì âñå äàííûå )
		virtual void Flush ()
		{
			// Ïèøåì âñå äàííûå, êîòîðûå åñòü
			if ( 0 < m_lWritePointer )
			{
				// Åñëè ïðèøëà îøèáêà, òî ãåíåðèðóåì èñêëþ÷åíèå
                                if ( false == WriteBuffer ( m_lWritePointer ) )
					throw 1;
			}
		}
		// Ñèê íà óêàçàííóþ ïîçèöèþ ïî ôàéëó
		virtual void Seek ( LONG64 lPosition, DWORD dwFrom/* = FILE_CURRENT */)
		{

			// Äîïèøåì ñíà÷àëà âñå äàííûå
			Flush ();

			if (dwFrom == 1/*FILE_CURRENT*/)
			{
				dwFrom += m_oFile.GetPosition();
			}

			if (m_oFile.SetPosition(lPosition) != S_OK)
				throw 1;

		}
		// Òåêóùàÿ ïîçèöèÿ 
                virtual void GetPosition(ULONG64& nPos)
		{
			nPos = m_oFile.GetPosition() + m_lWritePointer;

		}
		// Ðàçìåð çàïèñàííîãî ôàéëà
                virtual void GetSize(ULONG64& nLen)
		{
			nLen = m_oFile.GetFileSize() + m_lWritePointer;	

		}
	private :

		// Ñàìà çàïèñü íà äèñê
                bool WriteBuffer ( LONG64 lSize )
		{
			// Ïèøåì íà äèñê
			if (m_oFile.WriteFile(m_lpBuffer, ( DWORD ) lSize) != S_OK)
			{
				// Åñëè ÷òî-òî ïðîèçîøëî íå òàê, âîçâðàùàåì FALSE
                                return false;
			}
			// Ñáðàñûâàåì â 0 óêàçàòåëü íà ïîçèöèþ äàííûõ â áóôôåðå
			m_lWritePointer = 0;
                        return true;
		}
	};
}