geopm::CircularBuffer(3) – generic circular buffer

Namespaces

The CircularBuffer class is a member of the namespace geopm, but the full name, geopm::CircularBuffer, has been abbreviated in this manual. Similarly, the std:: namespace specifier has been omitted from the interface definitions for the following standard types: std::vector, std::pair, std::string, std::map, and std::function, to enable better rendering of this manual.

Synopsis

#include <geopm/CircularBuffer.hpp>

void CircularBuffer::set_capacity(const unsigned int size);

void CircularBuffer::clear(void);

int CircularBuffer::size(void) const;

int CircularBuffer::capacity(void) const;

void CircularBuffer::insert(const T value);

const T& CircularBuffer::value(const int index) const;

vector<T> CircularBuffer::make_vector(void) const;

vector<T> CircularBuffer::make_vector(const unsigned int start, const unsigned int end) const;

Description

The CircularBuffer container implements a fixed-size buffer. Once at capacity, any new insertions cause the oldest entry to be dropped.

Class Methods

set_capacity()

Grows or shrinks the capacity of the circular buffer. If the new capacity is greater than the size, then the current contents will not be modified. If the new capacity is smaller than the size, then only the newest elements of the difference will be retained.

clear()

Clears all entries from the buffer. The size becomes 0, but the capacity is unchanged.

size()

Returns the number of items in the buffer. This value will be less than or equal to the current capacity of the buffer.

capacity()

Returns the current size of the circular buffer at the time of the call.

insert()

Inserts value into the buffer. If the buffer is not full, the new value is simply added to the buffer. It the buffer is at capacity, The head of the buffer is dropped and moved to the next oldest entry and the new value is then inserted at the end of the buffer.

value()

Returns a constant reference to the value from the buffer. Accesses the contents of the circular buffer at a particular index.

• Valid positive indices range from 0 to size-1.

• Valid negative indices range from -1 to -size. Negative indices work just like python indices, to represent nth-most-recent insertions. For example, -1 is the last element, -2 is the second to last element, and so on.

Where size is the number of valid entries in the buffer.

• An out of bounds index is > [size-1] OR < [-size]. An attempt to retrieve a value for an out of bound index will throw a geopm::Exception(3) with an error_value() of GEOPM_ERROR_INVALID.

make_vector()

Create a vector from the entire circular buffer contents. Or create a vector slice from the circular buffer contents, delimited by the Start index (inclusive) and End index (exclusive) such as [start, end). If the range presented by these two indexes is invalid it will throw a geopm::Exception(3)

See Also

geopm(7), geopm::Exception(3)