create inital version of history

History/History.c

@@ -0,0 +1,123 @@
+#include "FIFOBuffChar.h"
+
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdio.h>
+
+History_t* History_init()
+{
+	History_t* history = malloc(sizeof(FIFOBuffChar_t));
+	
+	if (history != NULL) {
+		history->FirstEl_p = NULL;
+		history->LastEl_p = NULL;
+		history->size = 0;
+	}
+
+	return history;
+}
+
+
+int History_deinit(History_t* history)
+{
+	// Check if the buffer there is something in the buffer
+	if (history->FirstEl_p == NULL)
+	{
+		// Delete all elements in the buffer
+		History_element_t* el = history->FirstEl_p;
+		while (el != NULL)
+		{
+			FIFOBuffChar_element_t* nextEl = el->nextEl;
+			free(el);
+			el = nextEl;
+		}
+	}
+	
+	free(history);
+	return 0;
+}
+
+int History_put(History_t *history, char* line)
+{
+	int retCode;
+	if ((history->LastEl_p == NULL) && (history->FirstEl_p == NULL))
+	{
+		// buffer is empty. add first element
+		history->FirstEl_p = malloc(sizeof(History_element_t));
+		if (history->FirstEl_p != NULL)
+		{
+			history->FirstEl_p->line = line;
+			history->FirstEl_p->prev_p = NULL;
+			history->FirstEl_p->next_p = NULL;
+
+			history->LastEl_p = history->FirstEl_p;
+			history->size = 1;
+			retCode = 0;
+		}
+		else
+		{ // failt to allocate memory
+			retCode = -1;
+		}
+	}
+	else if ((history->LastEl_p != NULL) && (history->FirstEl_p != NULL))
+	{
+		// add element to exsiting buffer
+		History_element_t* el = malloc(sizeof(History_element_t));
+		if (el != NULL)
+		{
+			el->character = i;          // "value" to "character"
+			el->PrevEl_p = history->LastEl_p;
+			el->nextEl_p = NULL;
+			history->LastEl_p->nextEl_p = el;
+			history->LastEl_p = el;
+			history->size++;
+			retCode = 0;
+		}
+		else
+		{ // failt to allocate memory
+			retCode = -2;
+		}
+	}
+	else
+	{
+		retCode = -3;
+	}
+
+	if (retCode >= 0)
+	{
+		// reset current pointer
+		history->currEl_p = NULL;
+	}
+
+	return retCode;
+}
+
+int History_getPrev(History_t* history, char** line)
+{
+	int retCode;
+	if (history->currEl_p != NULL)
+	{
+		history->currEl_p = history->LastEl_p;
+	}
+	else
+	{
+		history->currEl_p = history->currEl_p->PrevEl_p;
+	}
+
+	if (history->currEl_p != NULL)
+	{
+		*line = history->currEl_p->line;
+		retCode = 0;
+	}
+	else
+	{
+		*line = NULL;
+		retCode = -1;
+	}
+	return 0;
+}
+
+unsigned int History_getSize(History_t *history)
+{
+	return history->size;
+}

History/history.h

@@ -0,0 +1,36 @@
+#ifndef HISTORY_H
+#define HISTORY_H
+
+#include <stdbool.h>
+
+// one element in the buffer
+typedef struct History_element_s {
+    void* prevEl_p;
+    char* line;
+    void* nextEl_p;
+} History_element_t;
+
+// defines all vars for the buffer to operate
+typedef struct History_s {
+    History_element_t* FirstEl_p;
+    History_element_t* LastEl_p;
+    History_element_t* CurrEl_p;
+    unsigned char size;
+} History_t;
+
+// create a fifo buffer and initilizes it with zeros
+extern History_t* History_init();
+
+// destroy a fifo buffer (free up its space)
+extern int History_deinit(History_t* history);
+
+// put value i in buffer if there is still memory avaliable
+extern int History_put(History_t *history, char* line);
+
+// get value from buffer and writes it to *line
+extern int History_getPrev(History_t* history, char** line);
+extern int History_getNext(History_t* history, char** line);
+
+extern unsigned int History_getSize(History_t *history);
+
+#endif