Test Commit

FIFOBuff/FIFOBuffChar.c

@@ -0,0 +1,158 @@
+#include <stdlib.h>
+#include <stddef.h>
+
+#include <stdio.h>
+
+#include "buffer.h"
+
+// implementation for a FIFO-buffer with ints
+// this very simple FIFO-buffer can only hold one int
+#define FIFO_SIZE 8
+
+typedef struct FIFO_element_s {
+    int value;
+    void* nextElement;
+} FIFO_element_t;
+
+// shared variables within this file
+static FIFO_element_t* FIFO_FirstElement_p = NULL;
+static FIFO_element_t* FIFO_LastElement_p = NULL;
+static unsigned int FIFO_count = 0;
+bool FIFO_Full = false;
+
+bool buffer_put(int i)
+{
+    bool ok = false;
+    if ((FIFO_LastElement_p == NULL) && (FIFO_FirstElement_p == NULL))
+    {
+        // buffer is empty. add first element
+        FIFO_FirstElement_p = malloc(sizeof(FIFO_element_t));
+        if (FIFO_FirstElement_p != NULL)
+        {
+            FIFO_FirstElement_p->value = i;
+            FIFO_FirstElement_p->nextElement = NULL;
+
+            FIFO_LastElement_p = FIFO_FirstElement_p;
+            FIFO_count = 1;
+            ok = true;
+        }
+        else
+        {
+            FIFO_Full = true;
+            ok = false;
+        }
+    }
+    else if ((FIFO_LastElement_p != NULL) && (FIFO_FirstElement_p != NULL))
+    {
+        // add element to exsiting buffer
+        FIFO_element_t* el = malloc(sizeof(FIFO_element_t));
+        if (el != NULL)
+        {
+            el->value = i;
+            el->nextElement = NULL;
+            FIFO_LastElement_p->nextElement = el;
+            FIFO_LastElement_p = el;
+            FIFO_count++;
+            ok = true;
+        }
+        else
+        {
+            FIFO_Full = true;
+            ok = false;
+        }
+    }
+    else
+    {
+        // buffer is unhealthy. try to clear it and reinit
+        if (FIFO_FirstElement_p == NULL)
+        {
+            printf("buffer_dyn - buffer_put(): ERROR: first pointer is NULL\n");
+        }
+        //TODO: this while loop is unsave
+        while (FIFO_FirstElement_p != NULL)
+        {
+            buffer_get(NULL);
+        }
+        if (FIFO_LastElement_p != NULL)
+        {
+            free(FIFO_LastElement_p);
+            FIFO_LastElement_p = NULL;
+            printf("buffer_dyn - buffer_put(): ERROR: last pointer is NULL\n");
+        }
+        buffer_put(i);
+        ok = false;
+    }
+    return ok;
+}
+
+bool buffer_get(int *p)
+{
+    bool ok = false;
+    if (FIFO_FirstElement_p != NULL)
+    {
+        *p = FIFO_FirstElement_p->value;
+        FIFO_element_t* next = FIFO_FirstElement_p->nextElement;
+        free(FIFO_FirstElement_p);
+        // FIFO_FirstElement_p = NULL;
+        FIFO_count--;
+        FIFO_Full = false;
+        if (next == NULL)
+        {
+            // this was the last element in the buffer
+            if (FIFO_LastElement_p == FIFO_FirstElement_p)
+            {
+                // clear last element becouse it's the same
+                FIFO_LastElement_p = NULL;
+                FIFO_FirstElement_p = NULL;
+                FIFO_count = 0;
+                ok = true;
+            }
+            else if (FIFO_LastElement_p != NULL)
+            {
+                // buffer chain is broken; skip to last element
+                FIFO_FirstElement_p = FIFO_LastElement_p;
+                printf("buffer_dyn - buffer_get(): ERROR: next element is NULL, but it's not the last element. skip to last element\n");
+                ok = false;
+            }
+            else
+            {
+                // somehow the last element is NULL
+                FIFO_count = 0;
+                FIFO_FirstElement_p = NULL;
+                printf("buffer_dyn - buffer_get(): ERROR: last element pointer is NULL\n");
+                ok = false;
+            }
+        }
+        else
+        {
+            // set first element pointer to next element
+            FIFO_FirstElement_p = next;
+            ok = true;
+        }
+    }
+    else
+    {
+        ok = false;
+    }
+    return ok;
+}
+
+bool buffer_is_full(void)
+{
+    return FIFO_Full;
+}
+
+bool buffer_is_empty(void)
+{
+    // printf("empty %s: %s; FIFO_LastElement_p = %i; FIFO_FirstElement_p = %i\n",
+    //     (FIFO_LastElement_p == NULL) && (FIFO_FirstElement_p == NULL) ? "true" : "false",
+    //     (FIFO_LastElement_p == FIFO_FirstElement_p) ? "same" : "diff",
+    //     (int) FIFO_LastElement_p,
+    //     (int) FIFO_FirstElement_p);
+    return ((FIFO_LastElement_p == NULL) && (FIFO_FirstElement_p == NULL));
+}
+
+unsigned int number_of_elements_in_buffer()
+{
+    return FIFO_count;
+}