From e96fabfe56085bbe2471ceaf671f7a6aa3131d8c Mon Sep 17 00:00:00 2001
From: Joseph Poirier <jdpoirier@gmail.com>
Date: Thu, 11 Jan 2018 23:04:24 -0600
Subject: [PATCH] fix linked list test

---
 tests/jpoirier/00_linked_list.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/tests/jpoirier/00_linked_list.c b/tests/jpoirier/00_linked_list.c
index a1ead0b..cb7f7fa 100644
--- a/tests/jpoirier/00_linked_list.c
+++ b/tests/jpoirier/00_linked_list.c
@@ -22,8 +22,10 @@ void enqueue_tail(int d) {
 	new_node->data = d;
 	new_node->next = tail;
 	new_node->prev = NULL;
+
 	if (tail != NULL)
 		tail->prev = new_node;
+
 	tail = new_node;
 	if (head == NULL)
 		head = tail;
@@ -36,12 +38,14 @@ void enqueue_tail(int d) {
 
 void enqueue_head(int d) {
 	struct Node *new_node = malloc(sizeof(*new_node));
-
+// 	printf("enqueue_head head: %p\n", (void*)head);
 	new_node->data = d;
 	new_node->next = NULL;
 	new_node->prev = head;
+
 	if (head != NULL)
 		head->next = new_node;
+
 	head = new_node;
 	if (tail == NULL)
 		tail = head;
@@ -64,7 +68,11 @@ int dequeue_tail(void) {
 	int d = tail->data;
 	if (tail->next != NULL)
 		tail->next->prev = NULL;
+
 	tail = tail->next;
+	if (t == head)
+		head = NULL;
+
 	free(t);
 	return d;
 }
@@ -79,14 +87,19 @@ int dequeue_head(void) {
 
 	struct Node *t = head;
 	int d = head->data;
+
 	if (head->prev != NULL) {
 		head->prev->next = NULL;
 	}
+
 	head = head->prev;
 
+// 	printf("B. dequeue_head t: %p\n", (void*)t);
 // 	printf("B. dequeue_head head: %p\n", (void*)head);
 // 	printf("B. dequeue_head head next: %p\n", (void*)((head == NULL) ? NULL : head->next));
 // 	printf("B. dequeue_head head prev: %p\n", (void*)((head == NULL) ? NULL : head->prev));
+	if (t == tail)
+		tail = NULL;
 
 	free(t);
 	return d;
@@ -99,6 +112,7 @@ void reverse_list(void) {
 	tmp1 = tail;
 	tail = head;
 	head = tmp1;
+
 	while (tmp1 != NULL) {
 		tmp2 = tmp1->next;
 		tmp1->next = tmp1->prev;
@@ -117,7 +131,6 @@ int main(int argc, char **argv) {
 	for (i = 0; i < COUNT; i++) {
 		printf("dequeue tail: %d\n", dequeue_tail());
 	}
-
 	for (i = 0; i < COUNT; i++) {
 		printf("enqueue head: %d\n", i);
 		enqueue_head(i);
@@ -125,7 +138,6 @@ int main(int argc, char **argv) {
 	for (i = 0; i < COUNT; i++) {
 		printf("dequeue head: %d\n", dequeue_head());
 	}
-
 	for (i = 0; i < 10; i++) {
 		printf("enqueue head: %d\n", i);
 		enqueue_head(i);