ringbuffer.h

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/**
 * @file ringbuffer.h
 *
 * A flexible ringbuffer class.
 */

#pragma once

#include <stddef.h>
#include <stdint.h>
#include <stdio.h>

namespace ringbuffer __EXPORT
{

class RingBuffer
{
public:
    RingBuffer(unsigned num_items, size_t item_size);
    virtual ~RingBuffer();

    /**
     * Put an item into the buffer.
     *
     * @param val       Item to put
     * @return      true if the item was put, false if the buffer is full
     */
    bool            put(const void *val, size_t val_size = 0);

    bool            put(int8_t val);
    bool            put(uint8_t val);
    bool            put(int16_t val);
    bool            put(uint16_t val);
    bool            put(int32_t val);
    bool            put(uint32_t val);
    bool            put(int64_t val);
    bool            put(uint64_t val);
    bool            put(float val);
    bool            put(double val);

    /**
     * Force an item into the buffer, discarding an older item if there is not space.
     *
     * @param val       Item to put
     * @return      true if an item was discarded to make space
     */
    bool            force(const void *val, size_t val_size = 0);

    bool            force(int8_t val);
    bool            force(uint8_t val);
    bool            force(int16_t val);
    bool            force(uint16_t val);
    bool            force(int32_t val);
    bool            force(uint32_t val);
    bool            force(int64_t val);
    bool            force(uint64_t val);
    bool            force(float val);
    bool            force(double val);

    /**
     * Get an item from the buffer.
     *
     * @param val       Item that was gotten
     * @return      true if an item was got, false if the buffer was empty.
     */
    bool            get(void *val, size_t val_size = 0);

    bool            get(int8_t &val);
    bool            get(uint8_t &val);
    bool            get(int16_t &val);
    bool            get(uint16_t &val);
    bool            get(int32_t &val);
    bool            get(uint32_t &val);
    bool            get(int64_t &val);
    bool            get(uint64_t &val);
    bool            get(float &val);
    bool            get(double &val);

    /*
     * Get the number of slots free in the buffer.
     *
     * @return      The number of items that can be put into the buffer before
     *          it becomes full.
     */
    unsigned        space(void);

    /*
     * Get the number of items in the buffer.
     *
     * @return      The number of items that can be got from the buffer before
     *          it becomes empty.
     */
    unsigned        count(void);

    /*
     * Returns true if the buffer is empty.
     */
    bool            empty();

    /*
     * Returns true if the buffer is full.
     */
    bool            full();

    /*
     * Returns the capacity of the buffer, or zero if the buffer could
     * not be allocated.
     */
    unsigned        size();

    /*
     * Empties the buffer.
     */
    void            flush();

    /*
     * resize the buffer. This is unsafe to be called while
     * a producer or consuming is running. Caller is responsible
     * for any locking needed
     *
     * @param new_size  new size for buffer
     * @return      true if the resize succeeds, false if
     *          not (allocation error)
     */
    bool            resize(unsigned new_size);

    /*
     * printf() some info on the buffer
     */
    void            print_info(const char *name);

private:
    unsigned        _num_items;
    const size_t        _item_size;
    char            *_buf;
    volatile unsigned   _head;  /**< insertion point in _item_size units */
    volatile unsigned   _tail;  /**< removal point in _item_size units */

    unsigned        _next(unsigned index);

    /* we don't want this class to be copied */
    RingBuffer(const RingBuffer &);
    RingBuffer operator=(const RingBuffer &);
};

} // namespace ringbuffer