From f3ad758e4f4344b58c2218db0c3eaa46b7e89fd4 Mon Sep 17 00:00:00 2001
From: Barry Kane <barry@omnimenu.ie>
Date: Fri, 11 Nov 2022 22:58:05 +0000
Subject: [PATCH] Preliminary implementation of linked-list.c

- Implemented first pass of linked-list.c.

TODO:
- Polish linked-list.c 'till you can see a reflection in it.
- Refactor existing codebase to use linked-list.c.y
---
 src/linkedlist.c             | 467 +++++++++++++++++++++++++++++++++++
 src/linkedlist.h             |  75 ++++++
 src/server/SilverMUDServer.c |   1 +
 tests/list-test.c            |  56 +++--
 4 files changed, 582 insertions(+), 17 deletions(-)
 create mode 100644 src/linkedlist.c
 create mode 100644 src/linkedlist.h

diff --git a/src/linkedlist.c b/src/linkedlist.c
new file mode 100644
index 0000000..7a8ccf8
--- /dev/null
+++ b/src/linkedlist.c
@@ -0,0 +1,467 @@
+// linkedlist.h: Function definitions for the list type for SilverMUD.
+// Barry Kane, 2022.
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include "playerdata.h"
+#include "linkedlist.h"
+
+// Deallocate a given list node, including it's data:
+static inline void deallocateListNode(listNode * node, listDataType type)
+{
+	// Delete the node:
+	switch(type)
+	{
+		case PLAYER:
+		{
+			deallocatePlayer(node->data.player);
+			break;
+		}
+		case AREA:
+		{
+//			destroyList(node->data.area->paths);
+			free(node->data.area);
+			free(node);
+			break;
+		}
+		case PATH:
+		{
+			free(node->data.path);
+			free(node);
+			break;
+		}
+		case SKILL:
+		{
+			free(node->data.skill);
+			free(node);
+			break;
+		}
+	}
+}
+
+// Allocates and instantiates a list of the specified type:
+list * createList(listDataType type)
+{
+	// Allocate and clear the memory for the list:
+	list * newList = calloc(sizeof(list), 1);
+
+	// Set the appropriate values in the new list:
+	newList->type = type;
+	newList->itemCount = 0;
+	newList->head = NULL;
+	newList->tail = NULL;
+
+	// Return the new list:
+	return newList;
+}
+
+// Deallocates a list and all of it's members:
+int destroyList(list ** list)
+{
+	// Check if the list is empty:
+	if((*list)->itemCount == 0)
+	{
+		free(*list);
+		list = NULL;
+		return 0;
+	}
+	else
+	{
+		while((*list)->itemCount > 0)
+		{
+			removeFromList((*list), (*list)->type, (*list)->itemCount - 1);
+		}
+		free(*list);
+		*list = NULL;
+		return 0;
+	}
+}
+
+// Returns the data at a given index in a list:
+listData * getFromList(list * list, size_t listIndex)
+{
+	// Check that we were given a valid index:
+	if(listIndex > (list->itemCount - 1))
+	{
+		perror("Invalid index specified.\n");
+		return NULL;
+	}
+	// Return the head if index is 0:
+	else if(listIndex == 0)
+	{
+		return &list->head->data;
+	}
+	// Loop through the entries in the list until we get to the right one:
+	else
+	{
+		listNode * currentNode = list->head;
+		while(listIndex-- > 0)
+		{
+			currentNode = currentNode->next;
+		}
+		return &currentNode->data;
+	}
+}
+
+// Returns the node at a given index in a list:
+listNode * getNodeFromList(list * list, size_t listIndex)
+{
+	// Check that we were given a valid index:
+	if(listIndex > (list->itemCount - 1))
+	{
+		perror("Invalid index specified.\n");
+		return NULL;
+	}
+	// Return the head if index is 0:
+	else if(listIndex == 0)
+	{
+		return list->head;
+	}
+	// Loop through the entries in the list until we get to the right one:
+	else
+	{
+		listNode * currentNode = list->head;
+		while(listIndex-- > 0)
+		{
+			currentNode = currentNode->next;
+		}
+		return currentNode;
+	}
+}
+
+// Adds the given data to the end of a list:
+listNode * addToList(list * list, void * data, listDataType type)
+{
+	// Check the type:
+	if(type != list->type)
+	{
+		fprintf(stderr, "Not the correct type for this list.\n");
+		return NULL;
+	}
+
+	// If this is the first item in the list:
+	if(list->itemCount == 0)
+	{
+		// Allocate the new node for the list:
+		list->head = calloc(1, sizeof(listNode));
+		
+		// Set the appropriate pointers for the list:
+		list->head->next = NULL;
+		list->head->previous = NULL;
+		list->tail = list->head;
+
+		// Add the data to the new node:
+		switch(type)
+		{
+			case PATH:
+			{
+				list->head->data.path = (playerPath *)data;
+				break;
+			}
+			case AREA:
+			{
+				list->head->data.area = (playerArea *)data;
+				break;
+			}
+			case PLAYER:
+			{
+				list->head->data.player = (playerInfo *)data;
+				break;
+			}
+			case SKILL:
+			{
+				list->head->data.skill = (playerSkill *)data;
+				break;
+			}
+		}
+	}
+	else
+	{	  
+		// Allocate the new node at the end of the list:
+		list->tail->next = calloc(1, sizeof(listNode));
+		
+		// Add the data to the new node:
+		switch(type)
+		{
+			case PATH:
+			{
+				list->tail->next->data.path = (playerPath *)data;
+				break;
+			}
+			case AREA:
+			{
+				list->tail->next->data.area = (playerArea *)data;
+				break;
+			}
+			case PLAYER:
+			{
+				list->tail->next->data.player = (playerInfo *)data;
+				break;
+			}
+			case SKILL:
+			{
+				list->tail->next->data.skill = (playerSkill *)data;
+				break;
+			}
+		}
+		
+		// Set the appropriate pointers in the new node:
+		list->tail->next->previous = list->tail;
+		
+		// Set the list's tail to the new tail:
+		list->tail = list->tail->next;
+	}
+    // Increase the count of items in the list:
+	list->itemCount++;
+
+	// Return the new item in the list:
+	return list->tail;
+}
+
+// Insert the given data at a given index in the list:
+listNode * insertIntoList(list * list, void * data, listDataType type, size_t listIndex)
+{
+	// Check that the types are correct:
+	if(list->type != type)
+	{
+		fprintf(stderr, "Types do not match.\n");
+		return NULL;
+	}
+	
+	// Handle the special case of adding to the end of the list:
+	if(listIndex == (list->itemCount - 1))
+	{
+		return addToList(list, data, type);
+	}
+
+	// Handle the special case of adding to the beginning of the list:
+	if(listIndex == 0)
+	{
+		// Create the new node:
+		listNode * newNode = calloc(1, sizeof(listNode));
+
+		// Add the data to the node:
+		switch(type)
+		{
+			case PATH:
+			{
+				newNode->data.path = (playerPath *)data;
+				break;
+			}
+			case AREA:
+			{
+				newNode->data.area = (playerArea *)data;
+				break;
+			}
+			case PLAYER:
+			{
+				newNode->data.player = (playerInfo *)data;
+				break;
+			}
+			case SKILL:
+			{
+				newNode->data.skill = (playerSkill *)data;
+				break;
+			}
+		}
+		
+		// Place it in the list:
+		newNode->next = list->head;
+		newNode->previous = NULL;
+		list->head->previous = newNode;
+		list->head = newNode;
+		list->itemCount++;
+
+		// Return the node:
+		return newNode;
+	}
+	
+	// Check that the index is valid:
+	if(listIndex > (list->itemCount - 1))
+	{
+		fprintf(stderr, "Index is invalid for the list.\n");
+		return NULL;
+	}
+	
+	// Get the current node at the index:
+	listNode * currentNode = list->head;
+	for(size_t index = 0; index < listIndex; index++)
+	{
+		currentNode = currentNode->next;
+	}
+
+	// Get the node before the current node:
+	listNode * previousNode = currentNode->previous;
+
+	// Create the new node:
+	previousNode->next = calloc(1, sizeof(listNode));
+	currentNode->previous = previousNode->next;
+	previousNode->next->next = currentNode;
+	previousNode->next->previous = previousNode;
+	
+	// Add the data to the node:
+	switch(type)
+	{
+		case PATH:
+		{
+			previousNode->next->data.path = (playerPath *)data;
+			break;
+		}
+		case AREA:
+		{
+			previousNode->next->data.area = (playerArea *)data;
+			break;
+		}
+		case PLAYER:
+		{
+			previousNode->next->data.player = (playerInfo *)data;
+			break;
+		}
+		case SKILL:
+		{
+			previousNode->next->data.skill = (playerSkill *)data;
+			break;
+		}
+	}
+	list->itemCount++;
+	return previousNode->next;
+}
+
+// Delete the given data from a list:
+bool deleteFromList(list * list, void * data, listDataType type)
+{
+	size_t index = 0;
+	if(getIndexFromList(list, data, type, &index) == false)
+	{
+		return false;
+	}
+	else
+	{
+		removeFromList(list, type, index);
+		return true;
+	}
+}
+
+// Delete the data from a given point in a list:
+int removeFromList(list * list, listDataType type, size_t listIndex)
+{
+	// Check that we're removing the correct type:
+	if(list->type != type)
+	{
+		return -1;
+	}
+	
+	// Check the list index is valid:
+	if(listIndex > list->itemCount - 1)
+	{
+		return -2;
+	}
+
+	// The first node in the list:
+	if(listIndex == 0)
+	{		
+		// Get the current head and move the list's head on:
+		listNode * oldHead = list->head;
+		list->head = list->head->next;
+		
+		// If we haven't removed the last item, set the previous pointer
+		// in the new head to null.
+		if(list->head != NULL)
+		{
+			list->head->previous = NULL;
+		}
+
+		// Delete the node:
+		deallocateListNode(oldHead, type);
+		
+		// Return the new amount of items in the list:
+		list->itemCount--;
+		return list->itemCount;
+	}
+	// The last node in the list:
+	else if(listIndex == (list->itemCount - 1))
+	{
+		// Move the tail up by one:
+		list->tail = list->tail->previous;
+
+		// Deallocate the former tail:
+		deallocateListNode(list->tail->next, type);
+
+		// Set the appropriate pointer:
+		list->tail->next = NULL;
+
+		// Return the new amount of items in the list:
+		list->itemCount--;
+		return list->itemCount;
+	}
+	// A node in the middle of the list:
+	else 
+	{
+		// Get the needed node as a pointer:
+		listNode * nodeToDelete = getNodeFromList(list, listIndex);
+
+		// Set the appropriate pointers for the surrounding nodes:
+		nodeToDelete->previous->next = nodeToDelete->next;
+		nodeToDelete->next->previous = nodeToDelete->previous;
+
+		// Deallocate the node:
+		deallocateListNode(nodeToDelete, type);
+		
+		// Return the new amount of items in the list:
+		list->itemCount--;
+		return list->itemCount;
+	}
+}
+
+// Get the index of a given piece of data in a list:
+bool getIndexFromList(list * list, void * data, listDataType type, size_t * index)
+{
+	// Check the list types are the same:
+	if(list->type == type)
+	{
+		fprintf(stderr, "List types do not match.\n");
+		return false;
+	}
+
+	for(*index = 0; *index < list->itemCount; *index++)
+	{
+		switch(type)
+		{
+			case AREA:
+			{
+				if(getFromList(list, *index)->area == data)
+				{
+					return true;					
+				}
+				break;
+			}
+			case PLAYER:
+			{
+				if(getFromList(list, *index)->player == data)
+				{
+					return true;					
+				}
+				break;				
+			}
+			case PATH:
+			{
+				if(getFromList(list, *index)->path == data)
+				{
+					return true;					
+				}
+				break;
+			}
+			case SKILL:
+			{
+				if(getFromList(list, *index)->skill == data)
+				{					
+					return true;
+				}
+				break;
+			}
+		}
+	}
+	return false;
+}
+
diff --git a/src/linkedlist.h b/src/linkedlist.h
new file mode 100644
index 0000000..ce75592
--- /dev/null
+++ b/src/linkedlist.h
@@ -0,0 +1,75 @@
+// linkedlist.h: Defines the linked list datatype for SilverMUD.
+// Barry Kane, 2022.
+#ifndef LINKEDLIST_H
+#define LINKEDLIST_H
+#include "playerdata.h"
+#include "areadata.h"
+
+// ========================
+// -=[ Data Structures ]=-:
+// ========================
+
+typedef enum listDataType
+{
+	PATH,
+	AREA,
+	PLAYER,
+	SKILL
+} listDataType;
+
+typedef union listData
+{
+	playerPath * path;
+	playerArea * area;
+	playerInfo * player;
+	playerSkill * skill;
+} listData;
+	
+typedef struct listNode listNode;
+typedef struct listNode
+{
+	listData data;
+	listNode * next;
+	listNode * previous;
+} listNode;
+
+typedef struct list
+{
+	listDataType type;
+	size_t itemCount;
+	listNode * head;
+	listNode * tail;
+} list;
+
+// ==================
+// -=[ Functions ]=-:
+// ==================
+
+// Allocates and instantiates a list of the specified type:
+list * createList(listDataType type);
+ 
+// Deallocates a list and all of it's members:
+int destroyList(list ** list);
+
+// Returns the data at a given index in a list:
+listData * getFromList(list * list, size_t listIndex);
+
+// Returns the node at a given index in a list:
+listNode * getNodeFromList(list * list, size_t listIndex);
+	
+// Adds the given data to the end of a list:
+listNode * addToList(list * list, void * data, listDataType type);
+
+// Insert the given data at a given index in the list:
+listNode * insertIntoList(list * list, void * data, listDataType type, size_t listIndex);
+
+// Delete the given data from a list:
+bool deleteFromList(list * list, void * data, listDataType type);
+
+// Delete the data from a given point in a list:
+int removeFromList(list * list, listDataType type, size_t listIndex);
+
+// Get the index of a given piece of data in a list:
+bool getIndexFromList(list * list, void * data, listDataType type, size_t * index);
+
+#endif
diff --git a/src/server/SilverMUDServer.c b/src/server/SilverMUDServer.c
index f2d9e1b..6c4dd69 100644
--- a/src/server/SilverMUDServer.c
+++ b/src/server/SilverMUDServer.c
@@ -21,6 +21,7 @@
 #include "../gamelogic.h"
 #include "../constants.h"
 #include "../playerdata.h"
+#include "../linkedlist.h"
 #include "../texteffects.h"
 #include "../inputoutput.h"
 
diff --git a/tests/list-test.c b/tests/list-test.c
index 9fbeb6a..94f3db1 100644
--- a/tests/list-test.c
+++ b/tests/list-test.c
@@ -1,24 +1,46 @@
-#include "../src/lists.h"
-#include "../src/playerdata.h"
+#include "../src/linkedlist.h"
 #include <stdio.h>
 
+static inline void printAreaList(list * areaList)
+{
+	listData * currentData;
+	for(int index = 0; index < areaList->itemCount; index++)
+	{
+		currentData = getFromList(areaList, index);
+		printf("%d\t| %s - %s\n", index, currentData->area->areaName, currentData->area->areaDescription);			
+	}
+}
+
 void main()
 {
-	areaNode * areaList = createAreaList(createArea("Test Area A", "This is Test Area A"));
-	areaNode * counter = areaList;
-	addAreaNodeToList(areaList, createArea("Test Area B", "This is Test Area B"));
-	addAreaNodeToList(areaList, createArea("Test Area C", "This is Test Area C"));
-	for(int index = 0; index <= 2; index++)
+	list * areaList = createList(AREA);
+	char areaName[256];
+	char areaDescription[256];
+	
+	printf("\n--==[ Generating a list of ten items. ]==--\n\n");
+	for(int count = 1; count <= 10; count++)
 	{
-		printf("%s\n", counter->data->areaName);
-		counter = counter->next;
-	}
-	deleteAreaNodeFromList(areaList, getAreaFromList(areaList, 1));
-	addAreaNodeToList(areaList, createArea("Test Area D", "This is Test Area D"));
-	counter = areaList;
-	for(int index = 0; index <= 2; index++)
-	{
-		printf("%s\n", counter->data->areaName);
-		counter = counter->next;
+		sprintf(areaName, "Area %d", count);
+		sprintf(areaDescription, "This is Area %d.", count);
+		
+		addToList(areaList, createArea(areaName, areaDescription) , AREA);
 	}
+	printAreaList(areaList);
+
+	printf("\n--==[ Inserting items into specific indexes. ]==--\n\n");
+	insertIntoList(areaList, createArea("Cool, it worked.", "Cool, it worked."), AREA, 0);
+	insertIntoList(areaList, createArea("Cool, it worked.", "Cool, it worked."), AREA, 6);
+	insertIntoList(areaList, createArea("Cool, it worked.", "Cool, it worked."), AREA, 11);
+	printAreaList(areaList);
+
+	printf("\n--==[ Removing certain areas from the list. ]==--\n\n");
+	removeFromList(areaList, AREA, 12);
+	removeFromList(areaList, AREA, 6);
+	removeFromList(areaList, AREA, 0);
+	
+	printAreaList(areaList);
+	
+	destroyList(&areaList);
+	printf("");
 }
+