Assignment 3 for glthread

Assignment3/glthread.c

@@ -0,0 +1,81 @@
+#include "glthread.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+/*Private function to add a new_node right after curr_node*/
+static void
+_glthread_add_next(glthread_node_t *curr_node, 
+                   glthread_node_t *new_node){
+
+    if(!curr_node->right){
+        curr_node->right = new_node;
+        new_node->left = curr_node;
+        return;
+    }
+
+    glthread_node_t *temp = curr_node->right;
+    curr_node->right = new_node;
+    new_node->left = curr_node;
+    new_node->right = temp;
+    temp->left = new_node;
+}
+
+/*Fn to insert a new GLnode into a glthread at the first position
+ * in a glthread i.e. new node becomes a head
+ * */
+void
+glthread_add (glthread_t *lst, glthread_node_t *glnode){
+
+    glnode->left = NULL;
+    glnode->right = NULL;
+    if(!lst->head){
+        lst->head = glnode;
+        return;
+    }
+    glthread_node_t *head = lst->head;
+    _glthread_add_next(glnode, head);
+    lst->head = glnode;
+}
+
+static void
+_remove_glthread(glthread_node_t *glnode){
+
+    if(!glnode->left){
+        if(glnode->right){
+            glnode->right->left = NULL;
+            glnode->right = 0;
+            return;
+        }
+        return;
+    }
+    if(!glnode->right){
+        glnode->left->right = NULL;
+        glnode->left = NULL;
+        return;
+    }
+
+    glnode->left->right = glnode->right;
+    glnode->right->left = glnode->left;
+    glnode->left = 0;
+    glnode->right = 0;
+}
+
+/*API to remove a glnode from glthread*/
+void
+glthread_remove(glthread_t *lst, glthread_node_t *glnode){
+
+    glthread_node_t *head = lst->head;
+    /*If the node being removed is the head node itself, then update the 
+     * head*/
+    if(head == glnode){
+        lst->head = head->right;
+    }
+    _remove_glthread(glnode);
+}
+
+void
+init_glthread(glthread_t *glthread, unsigned int offset){
+
+    glthread->head = NULL;
+    glthread->offset = offset;
+}