Jeroen Lodder
Multi purpose buffer module.
Multipurpose ringbuffer
Since there weren't any ringbuffers available on the internet optimized for 32-Bit ARM operation without unix-calls and dynamic memory... I created one.
This module is a fixed ringbuffer, it does not allocate any memory, it can work as FIFO or LIFO or any other exotic mode depending on your imagination. With a fixed 32Bit element size it is optimized for 32 bit arm processors. Any smaller value will have overhead, any larger value will require a double entry. (not recommended)
I hope you can use it.
Information
This is not a C++ class, it is a C Module. It does work object oriented, however you cannot work on the object, you work with the object.
Diff: xIFO.c
- Revision:
- 2:6013f6d867e5
- Parent:
- 1:5f59aa9b86ed
--- a/xIFO.c Mon Oct 28 19:20:00 2013 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,287 +0,0 @@
-
- /**
- * @file xifo.c
- * @brief xifo circular buffer
- * @details xifo supplies object oriented circular buffer with 32 bit size elements. \n
- * To use either as FIFO (First In First Out) or as FILO (First In Last Out)
- *
- * @Author Jeroen Lodder
- * @Date April 2013
- * @version 2
- *
- * @{
- */
-#include "xIFO.h"
-
-/**
- * @brief Initialise buffer object structure.
- *
- * @note Does not clear memory pool.
- *
- * @param[in] c Pointer to @p xifo_t object used for configuration.
- * @param[in] s Number of elements buffer can hold (size).
- * @param[in] sp Start of pre-allocated memory pool.
- */
-void xifo_init(xifo_t *c, uint32_t s, uint32_t *sp){
- c->startpool = sp;
- c->endpool = &sp[s-1];
- c->size = s;
- c->full = 0;
- c->elementcount = 0;
- c->read = sp;
- c->write = sp;
-}
-
-/**
- * @brief Clear buffer contents
- *
- * @note Must be used on initialised buffer object.
- *
- * @param[in] c Pointer to @p xifo_t object.
- */
-void xifo_clear(xifo_t *c){
- c->ptemp = c->startpool;
- while(c->ptemp <= c->endpool){
- *c->ptemp++ = 0;
- }
-}
-
-/**
- * @brief Read from buffer (lr) Least Recent oriented (fifo)
- *
- * @note Buffer state will be preserved
- *
- * @warning Consider this opertaion as atomic!
- *
- * @details Read n elements from the oldest element to the most recent.
- * As for index[0] the least recently added element is returned.
- * And for index[elementcount] the most recent element is returned.
- * This makes it possible to peek in fifo.
- *
- * @param[in] c Pointer to @p xifo_t used for configuration.
- * @param[in] index Index relative from least recent
- *
- * @return Contents of element or 0 if failed (element can hold 0)
- */
-uint32_t xifo_read_lr(xifo_t *c, uint32_t index){
- /* Verify there is valid data to read */
- if(index+1 > c->elementcount){
- return 0; /* Nothing to read there */
- }
- /* Calculate index of oldest element */
- index = (c->elementcount-1) - index;
- /* Set pointer */
- c->ptemp = (c->read) - index;
- if(c->ptemp < c->startpool){
- /* We exceeded pool boundaries */
- /* Calculate overshoot (startpool - indexptr) and subtract from end */
- /* Since one element of overshoot results in end - 1 you would miss the last value */
- c->ptemp = (c->endpool+1) - (c->startpool - c->ptemp);
- }
- /* Read most recent */
- return *c->ptemp;
-}
-
-/**
- * @brief Read from buffer (mr) Most Recent oriented (filo)
- *
- * @note Buffer state will be preserved
- *
- * @warning Consider this opertaion as atomic!
- *
- * @details Read n elements back in time.
- * As for index[0] the most recently added element is returned.
- * And for index[elementcount] the oldest element is returned.
- * This makes it possible to keep history. For DSP application.
- *
- * @param[in] c Pointer to @p xifo_t used for configuration.
- * @param[in] index Index relative from most recent
- *
- * @return Contents of element or 0 if failed (element can hold 0)
- */
-uint32_t xifo_read_mr(xifo_t *c, uint32_t index){
- /* Verify there is valid data to read */
- if(index+1 > c->elementcount){
- return 0; /* Nothing to read there */
- }
- /* Set pointer */
- c->ptemp = (c->read) - index;
- /* Validate pointer */
- if(c->ptemp < c->startpool){
- /* We exceeded pool boundaries */
- /* Calculate overshoot (startpool - indexptr) and subtract from end */
- /* Since one element of overshoot results in end - 1 you would miss the last value */
- c->ptemp = (c->endpool+1) - (c->startpool - c->ptemp);
- }
- /* Read most recent */
- return *c->ptemp;
-}
-
-/**
- * @brief Pop (mr) most recent from buffer (filo)
- *
- * @note Buffer state will be altered
- *
- * @warning Consider this opertaion as atomic!
- *
- * @details Read and remove the most recently added from the buffer.
- * Using this results in a stack type of buffer.
- *
- * @param[in] c Pointer to @p xifo_t used for configuration.
- *
- * @return Contents of element or 0 if failed (element can hold 0)
- */
-uint32_t xifo_pop_mr(xifo_t *c){
- /* Verify there is valid data read */
- if(c->elementcount == 0){
- return 0; /* Nothing to read there */
- }
- /* Read */
- c->temp = *c->read;
- /* Empty */
- *c->read = 0;
- /* Most recent element read, return write pointer */
- c->write = c->read;
- /* Decrement read pointer */
- c->read--;
- /* Validate pointer */
- if( c->read < c->startpool ){
- /* We exceeded pool boundaries */
- c->read = c->endpool;
- }
- /* Reduce elementcount */
- c->elementcount--;
- if(c->elementcount < c->size)
- c->full = 0;
- return c->temp;
-}
-
-/**
- * @brief Pop (lr) least recent from buffer (fifo)
- *
- * @note Buffer state will be altered
- *
- * @warning Consider this opertaion as atomic!
- *
- * @details Read and remove the least recently added from the buffer.
- * Using this results in a fifo type of buffer.
- *
- * @param[in] c Pointer to @p xifo_t used for configuration.
- *
- * @return Contents of element or 0 if failed (element can hold 0)
- */
-uint32_t xifo_pop_lr(xifo_t *c){
- /* Verify there is valid data read */
- if(c->elementcount == 0){
- return 0; /* Nothing to read there */
- }
- /* Derive least recent buffer element */
- c->ptemp = c->read+1 - c->elementcount;
- /* Validate pointer */
- if(c->ptemp < c->startpool){
- /* We exceeded pool boundaries */
- /* Calculate overshoot (startpool - indexptr) and subtract from end */
- /* Since one element of overshoot results in end - 1 you would miss the last value */
- c->ptemp = (c->endpool+1) - (c->startpool - c->ptemp);
- }
- /* Read oldest buffer element */
- { /* block with temporary variable to prevent stack use */
- register uint32_t element;
- /* Read to temp register */
- element = *c->ptemp;
- /* Empty */
- *c->ptemp = 0;
- /* Clear temp register */
- c->temp = element;
- }
- /* Reduce elementcount */
- c->elementcount--;
- /* Check full flag */
- if(c->elementcount < c->size)
- c->full = 0;
- return c->temp;
-}
-
-/**
- * @brief Write to buffer
- *
- * @note Readpointer is automatically set to the last added element.
- *
- * @warning Consider this opertaion as atomic!
- *
- * @details Adds a value to the buffer.
- * Automatically overwrites oldest elements when full.
- *
- * @param[in] c Pointer to @p xifo_t used for configuration.
- * @param[in] data Data to add to buffer
- *
- * @return Number of free buffer elements
- */
-uint32_t xifo_write(xifo_t *c, uint32_t data){
- /* Write data */
- *c->write = data;
- /* Update read pointer to most recent element */
- c->read = c->write;
- /* Write pointer increment */
- c->write += 1;
- /* Validate pointer */
- if( c->write > c->endpool){
- /* We exceeded pool boundaries */
- c->write = c->startpool;
- }
- /* Update elementcount */
- c->elementcount++;
- /* Verify full */
- if( c->elementcount >= c->size ){
- c->full = 1;
- c->elementcount = c->size;
- }
- /* return free elements count */
- return c->size - c->elementcount;
-}
-
-/**
- * @brief Get buffer size
- *
- * @param[in] c Pointer to @p xifo_t used for configuration.
- *
- * @return Size of memory pool in elements
- */
-uint32_t xifo_get_size(xifo_t *c){
- return c->size;
-}
-
-/**
- * @brief Get number of used elements
- *
- * @param[in] c Pointer to @p xifo_t used for configuration.
- *
- * @return Number of used buffer elements
- */
-uint32_t xifo_get_used(xifo_t *c){
- return c->elementcount;
-}
-
-/**
-* @brief Get number of free elements
-*
-* @param[in] c Pointer to @p xifo_t used for configuration.
-*
-* @return Number of free elements
-*/
-uint32_t xifo_get_free(xifo_t *c){
- return c->size - c->elementcount;
-}
-
-/**
- * @brief Get full flag
- *
- * @param[in] c Pointer to @p xifo_t used for configuration.
- *
- * @return 1 if full
- */
-uint32_t xifo_get_full(xifo_t *c){
- return c->full;
-}
-
-/** @} */