To read a list of variables at the same time. More...

#include <part.h>

Inheritance diagram for ibis::part::barrel:

Public Member Functions
	barrel (const ibis::part *t=0)

virtual long	close ()
	!< Open all data files.

const ibis::column *	getColumn (uint32_t i) const

void	getNullMask (ibis::bitvector &mask) const
	Collect the null masks together.

virtual long	open (const ibis::part *t=0)
	!< Destructor closes the open files. More...

virtual long	read ()
	!< Close all open files. More...

virtual long	seek (uint32_t pos)
	!< Read one value for each variable. More...

uint32_t	tell () const

virtual	~barrel ()
	Destructor. Member variables clean themselves.

Public Member Functions inherited from ibis::math::barrel
	barrel ()
	Constructor.

	barrel (const term *const t)
	Constructor.

bool	equivalent (const barrel &rhs) const
	Is the given `barrel` of variables equivalent to this one? More...

const char *	name (uint32_t i) const

void	recordVariable (const qExpr *const t)
	Record the variable names appear in the query expression. More...

void	recordVariable (const term *const t)
	Record the variable names appear in the `term`. More...

uint32_t	recordVariable (const char *name)
	Record the specified name. More...

uint32_t	size () const

const double &	value (uint32_t i) const

double &	value (uint32_t i)

Protected Attributes
const ibis::part *	_tbl

std::vector< const ibis::column * >	cols

std::vector< int >	fdes

uint32_t	position

std::vector< ibis::fileManager::storage * >	stores

Protected Attributes inherited from ibis::math::barrel
std::vector< const char * >	namelist
	List of variable names.

termMap	varmap
	Associate a variable name with a position in `varvalues` and `namelist`. More...

std::vector< double >	varvalues
	Cast values to double.

Additional Inherited Members
Protected Types inherited from ibis::math::barrel
typedef std::map< const char *, uint32_t, ibis::lessi >	termMap

Protected Member Functions inherited from ibis::math::barrel
double	getValue (uint32_t i) const

double	getValue (const char *nm) const
	Return the value of the named variable.

Detailed Description

To read a list of variables at the same time.

This implementation opens each data file and read the values from the files one at a time.

Member Function Documentation

long ibis::part::barrel::open ( const ibis::part * t = 0 )

virtual

!< Destructor closes the open files.

If the data files are on disk, then attempt to read the content through ibis::fileManager::getFile first.

If that fails, open the data file and so that each value can be read one at a time. If the data files are not on disk, it invokes the function getRawData to get a pointer to the raw data in memory. Upon successful completion, it returns 0, otherwise it returns a negative value to indicate error conditions.

The argument t may be left as nil if the barrel object was initialized with a valid pointer to the ibis::part object.

Reimplemented in ibis::part::vault.

References ibis::fileManager::storage::beginUse(), ibis::BLOB, ibis::CATEGORY, ibis::part::currentDataDir(), ibis::part::getColumn(), ibis::column::getRawData(), ibis::fileManager::instance(), ibis::part::name(), ibis::column::name(), ibis::TEXT, ibis::column::type(), ibis::TYPESTRING, and UnixOpen.