Added FIFO Pull function to remove one or more bytes from the FIFO. Added unit tests for FIFO Pull.

bacnet-stack/include/fifo.h

@@ -76,6 +76,11 @@ extern "C" {
     uint8_t FIFO_Get(
         FIFO_BUFFER * b);
 
+    unsigned FIFO_Pull(
+        FIFO_BUFFER * b,
+        uint8_t * data_bytes,
+        unsigned length);
+
     bool FIFO_Put(
         FIFO_BUFFER * b,
         uint8_t data_byte);

bacnet-stack/src/fifo.c

@@ -134,6 +134,41 @@ uint8_t FIFO_Get(
     return data_byte;
 }
 
+/****************************************************************************
+* DESCRIPTION: Pulls the data from the front of the list, and removes it
+* RETURN:      the data (in parameter) and the number of bytes pulled
+* ALGORITHM:   none
+* NOTES:       none
+*****************************************************************************/
+unsigned FIFO_Pull(
+    FIFO_BUFFER * b,
+    uint8_t * data_bytes,
+    unsigned length)
+{
+    unsigned count;
+    uint8_t data_byte;
+
+
+    count = FIFO_Count(b);
+    if (count > length) {
+        /* adjust to limit the number of bytes pulled */
+        count = length;
+    }
+    if (length > count) {
+        /* adjust the return value */
+        length = count;
+    }
+    while (count) {
+        data_byte = b->buffer[b->tail % b->buffer_len];
+        b->tail++;
+        *data_bytes = data_byte;
+        data_bytes++;
+        count--;
+    }
+
+    return length;
+}
+
 /****************************************************************************
 * DESCRIPTION: Adds an element of data to the FIFO
 * RETURN:      true on successful add, false if not added
@@ -226,6 +261,7 @@ void FIFO_Init(
 #ifdef TEST
 #include <assert.h>
 #include <string.h>
+#include <stdio.h>
 
 #include "ctest.h"
 
@@ -235,19 +271,18 @@ void FIFO_Init(
 void testFIFOBuffer(
     Test * pTest)
 {
-    FIFO_BUFFER test_buffer;
+    FIFO_BUFFER test_buffer = {0};
-    volatile uint8_t data_store[FIFO_BUFFER_SIZE];
+    volatile uint8_t data_store[FIFO_BUFFER_SIZE] = {0};
-    uint8_t test_add_data[40] = { "RoseSteveLouPatRachelJessicaDaniAmyHerb" };
+    uint8_t add_data[40] = { "RoseSteveLouPatRachelJessicaDaniAmyHerb" };
-    uint8_t test_data;
+    uint8_t test_add_data[40] = {0};
-    uint8_t index;
+    uint8_t test_data = 0;
-    uint8_t count;
+    unsigned index = 0;
-    bool status;
+    unsigned count = 0;
-    uint8_t cycles;
+    bool status = 0;
 
     FIFO_Init(&test_buffer, data_store, sizeof(data_store));
     ct_test(pTest, FIFO_Empty(&test_buffer));
 
-    for (cycles = 0; cycles < 32; cycles++) {
     /* load the buffer */
     for (test_data = 0; test_data < FIFO_BUFFER_SIZE; test_data++) {
         ct_test(pTest, !FIFO_Full(&test_buffer));
@@ -297,17 +332,42 @@ void testFIFOBuffer(
     }
     ct_test(pTest, FIFO_Empty(&test_buffer));
     /* test Add */
-        ct_test(pTest, FIFO_Available(&test_buffer, sizeof(test_add_data)));
+    ct_test(pTest, FIFO_Available(&test_buffer, sizeof(add_data)));
-        status = FIFO_Add(&test_buffer, test_add_data, sizeof(test_add_data));
+    status = FIFO_Add(&test_buffer, add_data, sizeof(add_data));
     ct_test(pTest, status == true);
+    count = FIFO_Count(&test_buffer);
+    ct_test(pTest, count == sizeof(add_data));
     ct_test(pTest, !FIFO_Empty(&test_buffer));
-        for (index = 0; index < sizeof(test_add_data); index++) {
+    for (index = 0; index < sizeof(add_data); index++) {
         /* unload the buffer */
         ct_test(pTest, !FIFO_Empty(&test_buffer));
         test_data = FIFO_Peek(&test_buffer);
-            ct_test(pTest, test_data == test_add_data[index]);
+        ct_test(pTest, test_data == add_data[index]);
         test_data = FIFO_Get(&test_buffer);
-            ct_test(pTest, test_data == test_add_data[index]);
+        ct_test(pTest, test_data == add_data[index]);
+    }
+    ct_test(pTest, FIFO_Empty(&test_buffer));
+    /* test Pull */
+    ct_test(pTest, FIFO_Available(&test_buffer, sizeof(add_data)));
+    status = FIFO_Add(&test_buffer, add_data, sizeof(add_data));
+    ct_test(pTest, status == true);
+    count = FIFO_Count(&test_buffer);
+    ct_test(pTest, count == sizeof(add_data));
+    ct_test(pTest, !FIFO_Empty(&test_buffer));
+    count = FIFO_Pull(&test_buffer, &test_add_data[0], sizeof(test_add_data));
+    ct_test(pTest, FIFO_Empty(&test_buffer));
+    ct_test(pTest, count == sizeof(test_add_data));
+    for (index = 0; index < sizeof(add_data); index++) {
+        ct_test(pTest, test_add_data[index] == add_data[index]);
+    }
+    ct_test(pTest, FIFO_Available(&test_buffer, sizeof(add_data)));
+    status = FIFO_Add(&test_buffer, test_add_data, sizeof(add_data));
+    ct_test(pTest, status == true);
+    ct_test(pTest, !FIFO_Empty(&test_buffer));
+    for (index = 0; index < sizeof(add_data); index++) {
+        count = FIFO_Pull(&test_buffer, &test_add_data[0], 1);
+        ct_test(pTest, count == 1);
+        ct_test(pTest, test_add_data[0] == add_data[index]);
     }
     ct_test(pTest, FIFO_Empty(&test_buffer));
     /* test flush */
@@ -316,7 +376,6 @@ void testFIFOBuffer(
     ct_test(pTest, !FIFO_Empty(&test_buffer));
     FIFO_Flush(&test_buffer);
     ct_test(pTest, FIFO_Empty(&test_buffer));
-    }
 
     return;
 }