first commit, initial layout and some ideas I want to implement, included my linked list impl

src/nickel/linkedlist.c

@@ -0,0 +1,67 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include "nickel/linkedlist.h"
+
+void ni_list__init(ni_list* l) 
+{
+    l->head.next = &l->head;
+    l->head.prev = &l->head;
+    l->count = 0;
+}
+
+bool ni_list__is_empty(ni_list* l) {
+    // only accept if head.next is head (circular head)
+    // as the indicator of empty-ness.
+    return l->head.next == &l->head;
+}
+
+void ni_list__insert_after(ni_list* l, ni_list_node* entry, ni_list_node* n) {
+    // setup our incomming node as the next node after the insert point
+    n->next = entry->next;
+    n->prev = entry;
+
+    // update the following node to point at our new next node
+    entry->next->prev = n;
+
+    // update the insert point to point at the new node 
+    entry->next = n;
+    l->count++;
+}
+
+void ni_list__insert_before(ni_list* l, ni_list_node* entry, ni_list_node* n) {
+    // setup our incomming node as the next node before the insert point
+    n->prev = entry->prev;
+    n->next = entry;
+
+    // update the previous node to point at our new next node
+    entry->prev->next = n;
+
+    // update our insert point with the new prev
+    entry->prev = n;
+    l->count++;
+}
+
+void ni_list__push_front(ni_list* l, ni_list_node* n) {
+    ni_list__insert_after(l, &l->head, n);
+}
+
+void ni_list__push_back(ni_list* l, ni_list_node* n) {
+    ni_list__insert_before(l, &l->head, n);
+}
+
+void ni_list__remove(ni_list* l, ni_list_node* n) {
+    // set node before our node to point back to the node after n.
+    n->prev->next = n->next;
+
+    // set node after our node to point back to the node before n
+    n->next->prev = n->prev;
+
+    // poison our removed node
+    n->next = NULL;
+    n->prev = NULL;
+
+    l->count--;
+}