utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment > Class Template Reference

#include <fileringbuffer.h>

Classes
class	DropCallback
struct	Item
struct	ItemPiece

Public Types
typedef std::deque< Item >	Items
	Typedef for convienient access.
typedef Items::const_iterator	const_iterator
	An const iterator in the buffer.

Public Member Functions
	FileRingBuffer (File *file, FilePos start_offset=0, FileSize max_size=0, DropCallback *drop_callback=nullptr)
const FileSize &	getCurrentSize ()
void	startWrappingAround ()
void	startAppending (Item *rear_data_item=nullptr, Item *last_data_item=nullptr)
void	appendItem (const void *data, size_t data_size, const ADDITIONAL_DATA &additional, FilePos *file_pos=nullptr)
void	appendItem (const ItemPiece *pieces, size_t count, const ADDITIONAL_DATA &additional, FilePos *file_pos=nullptr)
const_iterator	begin () const
const_iterator	end () const

Protected Member Functions
void	fillForAlignment ()
void	popFront ()

Detailed Description

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>
class utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >

File-based ring buffer.

A ring buffer implementation that supports variable sized elements and stores the actual data in a file. Mind that bookkeeping data is still kept in memory.

Use the template argument to store any additional data that you need in the drop callback which is called whenever an item is removed from the head of the buffer.

Start by calling the constructor with an already opend file. Then append items using the AppendItem() method. When you want to start wrapping around, call StartWrappingAround(). This will limit the ring buffer size by the current size. When you want to continue writing past the end of the ringbuffer, call StartAppending() and the file will then grow indefinitly.

Constructor & Destructor Documentation

FileRingBuffer()

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::FileRingBuffer ( File *  file, FilePos  start_offset = 0, FileSize  max_size = 0, DropCallback *  drop_callback = nullptr  )

inline

Constructor.

Parameters

[in]	file	A pointer to an open file.
[in]	start_offset	The offset where the ring buffer should start.
[in]	max_size	An optional size after which wrapping around will start. automatically, if zero, use StartWrappingAround.
[in]	drop_callback	A callback that will inform about dropped items.

Member Function Documentation

appendItem() [1/2]

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

void utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::appendItem ( const ItemPiece *  pieces, size_t  count, const ADDITIONAL_DATA &  additional, FilePos *  file_pos = nullptr  )

inline

Adds a new item that is made up by multiple data buffers at the end of the buffer.

Parameters

[in]	pieces	An array of item pieces.
[in]	count	The amount of pieces in the array.
[in]	additional	Additional bookkeeping data.
[out]	file_pos	The postion where the item was stored.

appendItem() [2/2]

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

void utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::appendItem ( const void *  data, size_t  data_size, const ADDITIONAL_DATA &  additional, FilePos *  file_pos = nullptr  )

inline

Adds a new item at the end of the buffer.

Parameters

[in]	data	The data of the item.
[in]	data_size	The size of the data.
[in]	additional	Additional bookkeeping data.
[out]	file_pos	The postion where the item was stored.

begin()

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

const_iterator utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::begin ( ) const

inline

Retunrs an iterator to the beginning of the buffer.

Returns

An iterator to the beginning of the buffer.

end()

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

const_iterator utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::end ( ) const

inline

Retuns an iterator to the end of the buffer.

Returns

An iterator to the end of the buffer.

fillForAlignment()

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

void utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::fillForAlignment ( )

inlineprotected

Writes data to the file until a field position is reached that satisfies the alignment requirement.

getCurrentSize()

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

const FileSize& utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::getCurrentSize ( )

inline

Returns the current size of the buffer.

Returns

The current size of the buffer.

popFront()

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

void utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::popFront ( )

inlineprotected

Removes the first item in the buffer.

startAppending()

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

void utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::startAppending ( Item *  rear_data_item = nullptr, Item *  last_data_item = nullptr  )

inline

After a call to this method, data will be appended after the ring buffer.

Parameters

[out]	rear_data_item	A pointer that will bes set to point to the rear item in the buffer (the position where the buffer wraps around).
[out]	last_data_item	A pointer that will bes set to point to the last item in the buffer.

startWrappingAround()

template<typename ADDITIONAL_DATA = uint8_t, uint8_t alignment = 1>

void utils5ext::FileRingBuffer< ADDITIONAL_DATA, alignment >::startWrappingAround ( )

inline

Limits the size of the buffer by the current size.

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

• include/utils5extension/fileringbuffer.h