CircularBuffer< T > Class Template Reference

A circular buffer containing a maximum of N entries of type T. More...

#include <CircularBuffer.h>

List of all members.

Public Member Functions
	CircularBuffer ()
	CircularBuffer (uint nEntriesInit)
void	clear ()
	Initializes the buffer to an empty state.
void	resize (uint nEntriesInit)
	Resizes the number of entries in the circular buffer.
uint	size ()
	Returns: max number of entries that can be stored in the buffer
bool	empty ()
	Returns: true if the buffer is empty
bool	spaceAvailable ()
	Returns: true if there is space available in the buffer
uint	nFreeSpace ()
	Returns: number of free entries available in the buffer
uint	getFirstPos ()
	Returns: the position of the first entry in the buffer
uint	getLastPos ()
	Returns: the position of the last entry in the buffer
T &	reference_back ()
	Returns: reference to the last entry in the buffer
void	push_back (T &newEntry)
	Adds an entry to the end of the buffer.
T &	reference_front ()
	Returns: reference to the first entry in the buffer
void	pop_front ()
	Removes the first entry from the buffer.
T &	operator[] (uint pos)
	Returns the entry at a specified position in the circular buffer.
bool	isReadOnly ()
	Returns: true if the buffer is readonly
void	setReadOnly ()
	Sets the buffer to a readonly state.
Private Member Functions
void	init (uint nEntriesInit)
	Initializes the buffer.
Private Attributes
std::vector< T >	buffer
	Vector used to represent the contents of the circular buffer.
uint	nEntries
	Number of entries in the buffer.
uint	nFreeEntries
	Number of free entries in the buffer.
uint	firstPos
	Position of the current, first entry in the circular buffer.
bool	readOnly
	If true, no additional new entries can be added to the buffer.

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Detailed Description

template<class T>
class CircularBuffer< T >

A circular buffer containing a maximum of N entries of type T.

The max size of the buffer must be set before the buffer can be used.

Definition at line 34 of file CircularBuffer.h.

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Constructor & Destructor Documentation

template<class T>

CircularBuffer< T >::CircularBuffer

(

)

[inline, explicit]

Definition at line 76 of file CircularBuffer.h.

    {
        init(0);
    }

template<class T>

CircularBuffer< T >::CircularBuffer

(

uint

nEntriesInit

)

[inline, explicit]

Definition at line 81 of file CircularBuffer.h.

    {
        init(nEntriesInit);
    }

---

Member Function Documentation

template<class T>

void CircularBuffer< T >::init

(

uint

nEntriesInit

)

[inline, private]

Initializes the buffer.

Parameters:

nEntriesInit

size of the buffer

Definition at line 68 of file CircularBuffer.h.

Referenced by CircularBuffer< std::pair< PageId, EntryT > >::CircularBuffer(), and CircularBuffer< std::pair< PageId, EntryT > >::resize().

    {
        nEntries = nEntriesInit;
        buffer.resize(nEntries);
        clear();
    }

template<class T>

void CircularBuffer< T >::clear

(

)

[inline]

Initializes the buffer to an empty state.

Definition at line 89 of file CircularBuffer.h.

Referenced by CircularBuffer< std::pair< PageId, EntryT > >::init(), SegPageEntryIter< EntryT >::mapRange(), LcsRowScanExecStream::open(), and LbmGeneratorExecStream::open().

    {
        firstPos = 0;
        nFreeEntries = nEntries;
        readOnly = false;
    }

template<class T>

void CircularBuffer< T >::resize

(

uint

nEntriesInit

)

[inline]

Resizes the number of entries in the circular buffer.

The buffer positions are also reset back to their initial state, so any existing entries stored in the buffer are ignored.

Parameters:

nEntriesInit

new number of entries

Definition at line 103 of file CircularBuffer.h.

Referenced by LcsRowScanExecStream::LcsRowScanExecStream(), LbmGeneratorExecStream::prepare(), and SegPageEntryIter< EntryT >::resize().

    {
        init(nEntriesInit);
    }

template<class T>

uint CircularBuffer< T >::size

(

)

[inline]

Returns:

max number of entries that can be stored in the buffer

Definition at line 111 of file CircularBuffer.h.

Referenced by SegPageEntryIter< EntryT >::setPrefetchSource().

    {
        return nEntries;
    }

template<class T>

bool CircularBuffer< T >::empty

(

)

[inline]

Returns:

true if the buffer is empty

Definition at line 119 of file CircularBuffer.h.

Referenced by CircularBuffer< std::pair< PageId, EntryT > >::getFirstPos(), SegPageEntryIter< EntryT >::operator++(), CircularBuffer< std::pair< PageId, EntryT > >::pop_front(), SegPageEntryIter< EntryT >::prefetchPages(), CircularBuffer< std::pair< PageId, EntryT > >::reference_back(), and CircularBuffer< std::pair< PageId, EntryT > >::reference_front().

    {
        return (nFreeEntries == nEntries);
    }

template<class T>

bool CircularBuffer< T >::spaceAvailable

(

)

[inline]

Returns:

true if there is space available in the buffer

Definition at line 127 of file CircularBuffer.h.

Referenced by LcsRowScanExecStream::fillRidRunBuffer(), and SegPageEntryIter< EntryT >::prefetchPages().

    {
        return (nFreeEntries != 0);
    }

template<class T>

uint CircularBuffer< T >::nFreeSpace

(

)

[inline]

Returns:

number of free entries available in the buffer

Definition at line 135 of file CircularBuffer.h.

Referenced by LcsRowScanExecStream::execute().

    {
        return nFreeEntries;
    }

template<class T>

uint CircularBuffer< T >::getFirstPos

(

)

[inline]

Returns:

the position of the first entry in the buffer

Definition at line 143 of file CircularBuffer.h.

    {
        assert(!empty());
        return firstPos;
    }

template<class T>

uint CircularBuffer< T >::getLastPos

(

)

[inline]

Returns:

the position of the last entry in the buffer

Definition at line 152 of file CircularBuffer.h.

Referenced by SegPageEntryIter< EntryT >::prefetchPages(), and CircularBuffer< std::pair< PageId, EntryT > >::reference_back().

    {
        return nEntries - nFreeEntries + firstPos - 1;
    }

template<class T>

T& CircularBuffer< T >::reference_back

(

)

[inline]

Returns:

reference to the last entry in the buffer

Definition at line 160 of file CircularBuffer.h.

Referenced by SegPageEntryIter< EntryT >::prefetchPages().

    {
        assert(!empty());
        uint lastEntry = getLastPos() % nEntries;
        return buffer[lastEntry];
    }

template<class T>

void CircularBuffer< T >::push_back

(

T &

newEntry

)

[inline]

Adds an entry to the end of the buffer.

Definition at line 170 of file CircularBuffer.h.

Referenced by LbmGeneratorExecStream::execute(), LcsRowScanExecStream::fillRidRunBuffer(), and SegPageEntryIter< EntryT >::prefetchPages().

    {
        assert(!readOnly);
        assert(nFreeEntries > 0);
        uint freeEntry = (nEntries - nFreeEntries + firstPos) % nEntries;
        buffer[freeEntry] = newEntry;
        nFreeEntries--;
    }

template<class T>

T& CircularBuffer< T >::reference_front

(

)

[inline]

Returns:

reference to the first entry in the buffer

Definition at line 182 of file CircularBuffer.h.

Referenced by SegPageEntryIter< LcsRid >::operator *(), and SegPageEntryIter< EntryT >::operator++().

    {
        assert(!empty());
        return buffer[firstPos % nEntries];
    }

template<class T>

void CircularBuffer< T >::pop_front

(

)

[inline]

Removes the first entry from the buffer.

Definition at line 191 of file CircularBuffer.h.

Referenced by SegPageEntryIter< EntryT >::operator++().

    {
        assert(!empty());
        firstPos++;
        nFreeEntries++;
    }

template<class T>

T& CircularBuffer< T >::operator[]

(

uint

pos

)

[inline]

Returns the entry at a specified position in the circular buffer.

Parameters:

pos

the position

Returns:

reference to the entry

Definition at line 205 of file CircularBuffer.h.

    {
        return buffer[pos % nEntries];
    }

template<class T>

bool CircularBuffer< T >::isReadOnly

(

)

[inline]

Returns:

true if the buffer is readonly

Definition at line 213 of file CircularBuffer.h.

    {
        return readOnly;
    }

template<class T>

void CircularBuffer< T >::setReadOnly

(

)

[inline]

Sets the buffer to a readonly state.

Definition at line 221 of file CircularBuffer.h.

Referenced by LcsRowScanExecStream::fillRidRunBuffer().

    {
        readOnly = true;
    }

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Member Data Documentation

template<class T>

std::vector<T> CircularBuffer< T >::buffer [private]

Vector used to represent the contents of the circular buffer.

Definition at line 39 of file CircularBuffer.h.

Referenced by CircularBuffer< std::pair< PageId, EntryT > >::init(), CircularBuffer< std::pair< PageId, EntryT > >::operator[](), CircularBuffer< std::pair< PageId, EntryT > >::push_back(), CircularBuffer< std::pair< PageId, EntryT > >::reference_back(), and CircularBuffer< std::pair< PageId, EntryT > >::reference_front().

template<class T>

uint CircularBuffer< T >::nEntries [private]

Number of entries in the buffer.

Definition at line 44 of file CircularBuffer.h.

Referenced by CircularBuffer< std::pair< PageId, EntryT > >::clear(), CircularBuffer< std::pair< PageId, EntryT > >::empty(), CircularBuffer< std::pair< PageId, EntryT > >::getLastPos(), CircularBuffer< std::pair< PageId, EntryT > >::init(), CircularBuffer< std::pair< PageId, EntryT > >::operator[](), CircularBuffer< std::pair< PageId, EntryT > >::push_back(), CircularBuffer< std::pair< PageId, EntryT > >::reference_back(), CircularBuffer< std::pair< PageId, EntryT > >::reference_front(), and CircularBuffer< std::pair< PageId, EntryT > >::size().

template<class T>

uint CircularBuffer< T >::nFreeEntries [private]

Number of free entries in the buffer.

Definition at line 49 of file CircularBuffer.h.

Referenced by CircularBuffer< std::pair< PageId, EntryT > >::clear(), CircularBuffer< std::pair< PageId, EntryT > >::empty(), CircularBuffer< std::pair< PageId, EntryT > >::getLastPos(), CircularBuffer< std::pair< PageId, EntryT > >::nFreeSpace(), CircularBuffer< std::pair< PageId, EntryT > >::pop_front(), CircularBuffer< std::pair< PageId, EntryT > >::push_back(), and CircularBuffer< std::pair< PageId, EntryT > >::spaceAvailable().

template<class T>

uint CircularBuffer< T >::firstPos [private]

Position of the current, first entry in the circular buffer.

Position always increases, even after positions in the circular buffer are recycled.

Definition at line 56 of file CircularBuffer.h.

Referenced by CircularBuffer< std::pair< PageId, EntryT > >::clear(), CircularBuffer< std::pair< PageId, EntryT > >::getFirstPos(), CircularBuffer< std::pair< PageId, EntryT > >::getLastPos(), CircularBuffer< std::pair< PageId, EntryT > >::pop_front(), CircularBuffer< std::pair< PageId, EntryT > >::push_back(), and CircularBuffer< std::pair< PageId, EntryT > >::reference_front().

template<class T>

bool CircularBuffer< T >::readOnly [private]

If true, no additional new entries can be added to the buffer.

Definition at line 61 of file CircularBuffer.h.

Referenced by CircularBuffer< std::pair< PageId, EntryT > >::clear(), CircularBuffer< std::pair< PageId, EntryT > >::isReadOnly(), CircularBuffer< std::pair< PageId, EntryT > >::push_back(), and CircularBuffer< std::pair< PageId, EntryT > >::setReadOnly().

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

• /home/pub/open/dev/fennel/common/CircularBuffer.h

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