stmbl

#pragma once

#include <string.h>

/**
 * Ringbuffer structure
 *
 */
struct ringbuf {
    char *buf;          ///< Pointer to buffer memory
    unsigned   bufsize;      ///< Size of buffer memory
    volatile unsigned pos;   ///< Current read position
    volatile unsigned len;   ///< Length of data in buffer
};


/**
 * Read a single byte from a buffer
 *
 * \param   rb    pointer to ringbuffer struct
 * \param   data  pointer to data byte
 * \return  number of bytes read (0 if buffer was empty)
 */
int rb_getc(struct ringbuf *rb, char *data);


/**
 * Write a single byte to a buffer
 *
 * \param   rb    pointer to ringbuffer struct
 * \param   data  pointer to data byte
 * \return  number of bytes written (0 if buffer was full)
 */
int rb_putc(struct ringbuf *rb, const char data);
/**
 * Read from a buffer
 *
 */
int rb_read(struct ringbuf *rb, void *data, int len);


/**
 * Write to a buffer
 *
 * \param   rb    pointer to ringbuffer struct
 * \param   data  pointer to data byte
 * \return  number of bytes written (0 if buffer was full)
 *
 */
int rb_write(struct ringbuf *rb, const void *data, int len);

/**
 * undo rb_read
 *
 * \param   rb    pointer to ringbuffer struct
 * \param   len   length to reset read pointer
 * \return  0 on error
 *
 */
int rb_undo(struct ringbuf *rb, int len);