Added linked lists to handle lists of column pointers in views (not

tested)

src/linked_list.c

@@ -0,0 +1,167 @@
+/****************************************************************************
+ * Linked list source file	                                                *
+ ****************************************************************************/
+
+/**
+ * @file linked_list.c
+ * @author Celine Mercier
+ * @date February 22th 2017
+ * @brief Source file for linked list functions.
+ */
+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include "linked_list.h"
+
+
+/**
+ * @brief Creates a new node.
+ *
+ * @warning The returned pointer has to be freed by the caller.
+ *
+ * @returns A pointer on the new node.
+ * @retval NULL if an error occurred.
+ *
+ * @since February 2017
+ * @author Celine Mercier (celine.mercier@metabarcoding.org)
+ */
+static Linked_list_node_p create_node();
+
+
+static Linked_list_node_p create_node()
+{
+	Linked_list_node_p node;
+
+	node = malloc(sizeof(Linked_list_node_t));
+	if (node == NULL)
+		return NULL;
+
+	node->value = NULL;
+	node->previous = NULL;
+	node->next = NULL;
+
+	return node;
+}
+
+
+// Add a value at the end of a linked list
+Linked_list_node_p ll_add(Linked_list_node_p head, void* value)
+{
+	Linked_list_node_p node = head;
+	Linked_list_node_p new_node = NULL;
+
+	// First node
+	if (head == NULL)
+	{
+		head = create_node();
+		if (head == NULL)
+			return NULL;
+		head->value = value;
+	}
+
+	else
+	{
+		while (node->next != NULL)
+			node = node->next;
+
+		new_node = create_node();
+		if (new_node == NULL)
+			return NULL;
+		node->next = new_node;
+		new_node->previous = node;
+		new_node->value = value;
+	}
+
+	return head;
+}
+
+
+// Set a value at a given index of the list
+int ll_set(Linked_list_node_p head, int idx, void* value)
+{
+	int i = 0;
+	Linked_list_node_p node = head;
+
+	while ((node != NULL) && (i < idx))
+	{
+		node = node->next;
+		i++;
+	}
+
+	if (node == NULL)	// End of list reached before index
+		return -1;
+
+	node->value = value;
+
+	return 0;
+}
+
+
+// Get a node with its index
+Linked_list_node_p ll_get(Linked_list_node_p head, int idx)
+{
+	int i = 0;
+	Linked_list_node_p node = head;
+
+	while ((node != NULL) && (i < idx))
+	{
+		node = node->next;
+		i++;
+	}
+
+	return node;
+}
+
+
+// Delete a node
+Linked_list_node_p ll_delete(Linked_list_node_p head, int idx) 	// TODO or with value?
+{
+	int i = 0;
+	Linked_list_node_p node = head;
+
+	while ((node != NULL) && (i < idx))
+	{
+		node = node->next;
+		i++;
+	}
+
+	if (node == NULL)	// Node didn't exist
+		return NULL;
+
+	if (node->previous != NULL)
+		(node->previous)->next = node->next;
+	else  // deleting head node: head changes
+		head = node->next;
+
+	if (node->next != NULL)
+		(node->next)->previous = node->previous;
+
+	free(node);
+
+	return head;
+}
+
+
+// Free the linked list
+void ll_free(Linked_list_node_p head)
+{
+	Linked_list_node_p node = head;
+	Linked_list_node_p previous = head;
+
+	while (node != NULL)
+	{
+		previous = node;
+		node = node->next;
+		free(previous);
+	}
+}
+
+
+// Get the index of a node from its value (TODO useless?) -- kinda assumes unique values
+//int ll_get_index(Linked_list_node_p head, void* value)
+//{
+//
+//}