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89 lines
2.8 KiB
C
89 lines
2.8 KiB
C
// Resource/Inspiration: https://embedjournal.com/implementing-circular-buffer-embedded-c/
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/*
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Penguin's Circular Buffer -- a simple floating queue designed for low memory usage (mainly for embedded)
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This is a ring buffer with limited capabilities. It is meant as a container for moving data.
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Normally included features such as checks to see if the buffer is full or empty have been omitted
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because this type of buffer is being implemented mainly for sensor data usage. Data is almost never read
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individually, and even if it is, it isn't meant to be cleared on read. It is a simple moving buffer that
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automatically writes over old data for the purpose of keeping track of the most up to date data.
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Notes:
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- Initialization is mandatory using p_cb_<type>_init.
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- If a circular buffer is not initialized, you will run into a LOT of hard-to-debug problems. Just initialize it.
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- By default, all cb types should be defined as disabled. This is to save on size. Enable the ones you want to use.
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Behavior:
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- Oldest data is overwritten
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- popping of data isn't implemented. If this feature is required, use a ring buffer.
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Acronyms:
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- p: penguin
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- pb: penguin buffer
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- cb: circular buffer
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- uX, where X is bit size: unsigned X bit integer
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- iX, where X is bit size: signed X bit integer
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Note: I wrote this like 3 years ago or something. I hope it works.
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*/
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#ifndef _PCIRCULARBUFFER_H_
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#define _PCIRCULARBUFFER_H_
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#include "p_serial_mgr.h"
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#include <stdbool.h>
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#include <stdint.h>
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#ifdef _DEBUG
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#define PC_CB_DEBUG
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#endif
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// Max size is 65535 (2^16 - 1) so variables can be safely set 16 bits (unsigned)
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// If you want to change this, you'll need to change the sizes of all heads and max lengths
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#define PB_CB_MAX_BUFFER_SIZE (65535)
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typedef enum PB_CB_STATUS
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{
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PB_CB_GOOD = 0,
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PB_CB_BAD = 1,
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PB_CB_BAD_BUFFER_SIZE = 2,
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PB_CB_NULL_BUFFER = 3,
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PB_CB_NULL_CBUFFER = 4
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} PB_CB_STATUS;
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typedef struct p_cb_u8
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{
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uint8_t *buffer;
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uint16_t head;
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uint16_t max_len;
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// Signifies the buffer being filled at least once.
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// Useful for initializing sensor data
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bool b_filled;
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// Signifies the buffer being empty
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// Useful for knowing if data is being received
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bool b_empty;
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PB_CB_STATUS (*push)(struct p_cb_u8 *cbuffer, uint8_t value);
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PB_CB_STATUS (*empty)(struct p_cb_u8 *cbuffer);
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} p_cb_u8;
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PB_CB_STATUS p_cb_u8_init(p_cb_u8 *circ_buffer, uint8_t *buff, uint32_t max_length);
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typedef struct p_cb_serial_pkt_t
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{
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serial_pkt_t *buffer;
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uint16_t head;
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uint16_t max_len;
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bool b_filled;
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// Signifies the buffer being empty
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// Useful for knowing if data is being received
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bool b_empty;
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PB_CB_STATUS (*push)(struct p_cb_u8 *cbuffer, uint8_t value);
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PB_CB_STATUS (*empty)(struct p_cb_u8 *cbuffer);
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} p_cb_serial_pkt_t;
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PB_CB_STATUS p_cb_serial_pkt_init(p_cb_serial_pkt_t *inst, serial_pkt_t *buff, uint32_t max_length);
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#endif
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