tpie::queue< T > Class Template Reference

Basic Implementation of I/O Efficient FIFO queue. More...

#include <tpie/queue.h>

Public Member Functions
	queue (stream_size_type elements=std::numeric_limits< stream_size_type >::max(), double block_factor=1.0)
	Constructor for Temporary Queue. More...
void	resize (stream_size_type)
	Does nothing. More...
	queue (const std::string &basename, double block_factor=1.0)
	Load or create a named queue. More...
	~queue ()
	Destructor, closes the underlying stream. More...
bool	empty ()
	Check if the queue is empty. More...
	TPIE_DEPRECATED (bool is_empty())
stream_size_type	size ()
	Returns the number of items currently on the queue. More...
void	push (const T &t)
	Enqueue an item. More...
	TPIE_DEPRECATED (ami::err enqueue(const T &t))
const T &	pop ()
	Dequeues an item. More...
	TPIE_DEPRECATED (ami::err dequeue(const T **t))
const T &	front ()
	Returns at the frontmost item in the queue. More...
	TPIE_DEPRECATED (ami::err peek(const T **t))
	TPIE_DEPRECATED (ami::err trim())
	Deprecated, does nothing. More...
	TPIE_DEPRECATED (void persist(persistence p))
	Set the persistence status of the (stacks underlying the) queue. More...

Static Public Member Functions
static memory_size_type	memory_usage (double blockFactor=1.0)
	Compute the memory used by the queue. More...

Detailed Description

template<class T>
class tpie::queue< T >

Basic Implementation of I/O Efficient FIFO queue.

Author

The TPIE Project

Definition at line 42 of file queue.h.

Constructor & Destructor Documentation

template<class T >

tpie::queue< T >::queue ( stream_size_type  elements = std::numeric_limits<stream_size_type>::max(), double  block_factor = 1.0  )

inline

Constructor for Temporary Queue.

Definition at line 47 of file queue.h.

References tpie::access_read_write, and tpie::unused().

                                  : m_size(0), m_file(block_factor) {
        m_file.open(m_temp, access_read_write, sizeof(stream_size_type) );
        m_back.attach(m_file);
        m_front.attach(m_file);
        unused(elements);
    }

template<class T >

tpie::queue< T >::queue	(	const std::string &	basename,
		double	block_factor = 1.0
	)

Load or create a named queue.

Parameters

basename

The base name of the queue to load/create

Definition at line 152 of file queue.h.

References tpie::access_read_write, and tpie::temp_file::set_persistent().

                                                            : 
    m_temp(basename), m_size(0), m_file(blockFactor), m_back(m_file), m_front(m_file) {
    m_temp.set_persistent(true);
    m_file.open(basename, access_read_write, sizeof(stream_size_type) );
    if (m_file.size() != 0) {
        stream_size_type t;
        m_file.read_user_data(t);
        m_front.seek(t);
    }
    m_back.seek(0, file_base::stream::end);
    m_size = m_back.offset() - m_front.offset();
}

template<class T >

tpie::queue< T >::~queue ( )

inline

Destructor, closes the underlying stream.

Definition at line 71 of file queue.h.

{m_file.write_user_data(m_back.offset());}

Member Function Documentation

template<class T >

bool tpie::queue< T >::empty ( )

inline

Check if the queue is empty.

Returns

true if the queue is empty otherwize false

Definition at line 77 of file queue.h.

{return m_size == 0;}

template<class T >

const T& tpie::queue< T >::front ( )

inline

Returns at the frontmost item in the queue.

Returns

The front most item in the queue

Definition at line 111 of file queue.h.

                      {
        const T & el = m_front.read();
        m_front.seek(-1, file_base::stream::current);
        return el;
    }

template<class T >

static memory_size_type tpie::queue< T >::memory_usage ( double  blockFactor = 1.0 )

inlinestatic

Compute the memory used by the queue.

Definition at line 126 of file queue.h.

                                                                 {
        return sizeof(queue<T>)
            + file<T>::memory_usage() - sizeof(file<T>)
            + 2*file<T>::stream::memory_usage(blockFactor) - 2*sizeof(typename file<T>::stream);
    }

template<class T >

const T& tpie::queue< T >::pop ( )

inline

Dequeues an item.

Returns

The dequeued item

Definition at line 100 of file queue.h.

                    {
        const T & el = m_front.read();
        --m_size;
        return el;
    }

template<class T >

void tpie::queue< T >::push ( const T &  t )

inline

Enqueue an item.

Parameters

t	The item to be enqueued

Definition at line 90 of file queue.h.

                                  {
        m_back.write(t);
        ++m_size;
    }

template<class T >

void tpie::queue< T >::resize ( stream_size_type  )

inline

Does nothing.

This method is included so the interface is compatible with internal_queue

Definition at line 60 of file queue.h.

{}

template<class T >

stream_size_type tpie::queue< T >::size ( )

inline

Returns the number of items currently on the queue.

Returns

Number of itmes in the queue

Definition at line 84 of file queue.h.

{return m_size;}

template<class T >

tpie::queue< T >::TPIE_DEPRECATED

(

ami::err

trim()

)

Deprecated, does nothing.

template<class T >

tpie::queue< T >::TPIE_DEPRECATED

(

void

persistpersistence p

)

Set the persistence status of the (stacks underlying the) queue.

Parameters

p	A persistence status.

---

The documentation for this class was generated from the following file:

• queue.h