Buffer.cpp

00001 #include "Buffer.h"
00002 #include "mbed.h"
00003 
00004 int circular_buf_reset(circular_buf_t * cbuf)
00005 {
00006     int r = -1;
00007 
00008     if(cbuf) {
00009         cbuf->head = 0;
00010         cbuf->tail = 0;
00011         cbuf->size = 0;
00012         r = 0;
00013     }
00014 
00015     return r;
00016 
00017 }
00018 
00019 bool circular_buf_empty(circular_buf_t cbuf)
00020 {
00021     // We define empty as head == tail
00022     return (cbuf.head == cbuf.tail);
00023 }
00024 
00025 bool circular_buf_full(circular_buf_t cbuf)
00026 {
00027     // We determine "full" case by head being one position behind the tail
00028     // Note that this means we are wasting one space in the buffer!
00029     // Instead, you could have an "empty" flag and determine buffer full that way
00030     return ((cbuf.head + 1) % cbuf.size) == cbuf.tail;
00031 }
00032 
00033 int circular_buf_put(circular_buf_t * cbuf, uint8_t data)
00034 {
00035     int r = -1;
00036 
00037     if(cbuf) {
00038         cbuf->buffer[cbuf->head] = data;
00039         cbuf->head = (cbuf->head + 1) % cbuf->size;
00040 
00041         if(cbuf->head == cbuf->tail) {
00042             cbuf->tail = (cbuf->tail + 1) % cbuf->size;
00043         }
00044 
00045         r = 0;
00046     }
00047 
00048     return r;
00049 }
00050 
00051 int circular_buf_get(circular_buf_t * cbuf, uint8_t * data)
00052 {
00053     int r = -1;
00054 
00055     if(cbuf && data && !circular_buf_empty(*cbuf)) {
00056         *data = cbuf->buffer[cbuf->tail];
00057         cbuf->tail = (cbuf->tail + 1) % cbuf->size;
00058 
00059         r = 0;
00060     }
00061 
00062     return r;
00063 }