#include "StdAfx.h"
#include "TFile.h"
#include "RelationData.h"

CTFile::CTFile(void) : m_pFile(NULL)
{
}

CTFile::~CTFile(void)
{
	if( m_pFile )
	{
		fclose( m_pFile );
	}
}

int CTFile::CreateEmptyFile( const char* strName, unsigned int FileSize, FILE** ppFile )
{
	int nRet = -1;

	FILE *pFile = NULL;

	do 
	{
		pFile = fopen( strName, "wb" );
		if( pFile == NULL )	 break;
		char ch[512]= {0};

		for( unsigned long i=0; i<FileSize/512; i++ )
		{
			fwrite( &ch, sizeof(char), 512, pFile );
		}

		nRet = fseek( pFile, 0, SEEK_END );
		if( nRet != 0 )	break;

		fpos_t curpos;
		nRet = fgetpos( pFile, &curpos );
		if( nRet != 0 )	break;

		if( curpos == FileSize )
			nRet = 0;
		else
			nRet = -1;

	} while(0);

	if( pFile )
	{
		*ppFile = pFile;	
	}

	return nRet;
}

BOOL CTFile::GetFileHeader(void* pData )
{
	return GetItem( 0, pData );
}

BOOL CTFile::OpenFile(const char* FileName, BOOL* IsNewFile )
{
	int nRet = 0;
	
	*IsNewFile = FALSE;
	if( m_pFile )
	{
		fclose( m_pFile );
	}

	m_pFile = fopen( FileName, "r+b" );
	if( m_pFile == NULL )
	{
		nRet = CreateEmptyFile( FileName, RELATION_FILE_SIZE, &m_pFile );	
		*IsNewFile = TRUE;
	}

	if( nRet == 0 && m_pFile )
	{
		return TRUE;
	}
	else
	{
		return FALSE;
	}
}


int CTFile::WriteFile( FILE *pFile, const void* buf, unsigned int bufsize, long pos )
{
	int nRet = -1;
	do 
	{
		nRet = fseek( pFile, pos, SEEK_SET );
		if( nRet != 0 )	break;

		size_t writesize = fwrite( buf, sizeof(char), bufsize, pFile );

		if( writesize == (size_t)bufsize )
			nRet = 0;
		else
			nRet = -1;
	} while(0);

	return nRet;
}



int CTFile::ReadFile( FILE *pFile, void* buf, unsigned int BufSize, long pos )
{
	int nRet = -1;

	do 
	{
		nRet = fseek( pFile, pos, SEEK_SET );
		if( nRet != 0 )	break;

		size_t readsize = fread( buf, sizeof(char), BufSize, pFile );

		if( readsize == (size_t)BufSize )
			nRet = 0;
		else
			nRet = -1;

	} while(0);

	return nRet;
}

BOOL CTFile::GetItem(long pos, void* pData )
{
	int nRet = -1;
	
	do 
	{
		if( m_pFile == NULL )	break;
		nRet = ReadFile( m_pFile, pData, DATA_UNIT, pos*DATA_UNIT );
	} while( 0 );

	return nRet == 0 ? TRUE : FALSE;
}

BOOL CTFile::WriteItem(long pos, void* pData )
{
	int nRet = -1;

	do 
	{
		if( m_pFile == NULL )	break;
		nRet = WriteFile( m_pFile, pData, DATA_UNIT, pos*DATA_UNIT );
	} while(0);

	return nRet == 0 ? TRUE : FALSE;
}