size_t VorbisfileUser::readFunc(void *ptr, size_t size, size_t nmemb, void *datasource)
{
	VorbisfileUser *vu ;
	vu = (VorbisfileUser *)datasource ;

	DWORD	readedBytes ;
	ReadFile(vu->srcFile, ptr, (DWORD)(size*nmemb), &readedBytes, NULL) ;

	return readedBytes ;
}

int VorbisfileUser::seekFunc(void *datasource, ogg_int64_t offset, int whence)
{
	VorbisfileUser *vu ;
	vu = (VorbisfileUser *)datasource ;

	DWORD moveMethod;
	DWORD to;
	if(whence == SEEK_CUR){
		moveMethod = FILE_CURRENT;
		to = (DWORD)offset;
	}
	else if(whence == SEEK_END){
		moveMethod = FILE_END ;
		to = (DWORD)offset ;
	}
	else if(whence == SEEK_SET){
		moveMethod = FILE_BEGIN;
		to = (DWORD)offset ;
	}
	else{
		return -1;
	}

	DWORD result = SetFilePointer(vu->srcFile, to, NULL, moveMethod);


	return (result == 0xffffffff) ? -1 : 0;
}

int VorbisfileUser::closeFunc(void *datasource)
{
	VorbisfileUser *vu ;
	vu = (VorbisfileUser *)datasource ;
	CloseHandle(vu->srcFile) ;
	vu->srcFile = NULL ;

	return 0 ;
}

long VorbisfileUser::tellFunc(void *datasource)
{
	DWORD filePointer ;
	VorbisfileUser *vu ;
	vu = (VorbisfileUser *)datasource ;
	filePointer = SetFilePointer(vu->srcFile, 0, NULL, FILE_CURRENT) ;

	return filePointer ;
}