From be3baee74e6eb7df16fd15769a61c6b92230903f Mon Sep 17 00:00:00 2001
From: Jacob Signorovitch <jacob.signorovitch@gmail.com>
Date: Tue, 4 Feb 2025 16:40:58 -0500
Subject: [PATCH] Fixed dlists.

Also added tests.
---
 src/dlist.c         | 10 +++++-----
 src/include/dlist.h |  2 +-
 test/test_dlist.c   | 41 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 6 deletions(-)
 create mode 100644 test/test_dlist.c

diff --git a/src/dlist.c b/src/dlist.c
index b87d926..51f38d2 100644
--- a/src/dlist.c
+++ b/src/dlist.c
@@ -21,9 +21,9 @@ void dlist_destroy(DList* dlist) {
 
 void dlist_destroypsv(DList* dlist) { free(dlist); }
 
-// Check whether the buffer is overflowing and resize it if necessary.
-void dlist_check_resz(DList* dlist, size_t ln) {
-    while (dlist->ln + ln + 1 > dlist->sz) {
+// Check whether the buffer is about to overflow and resize it if necessary.
+void dlist_check_resz(DList* dlist) {
+    while ((dlist->ln + 1) * sizeof(void*) >= dlist->sz) {
         // Double the buffer size when overflown.
         dlist->sz *= 2;
         dlist->buf = realloc(dlist->buf, dlist->sz);
@@ -34,8 +34,8 @@ void dlist_check_resz(DList* dlist, size_t ln) {
 }
 
 void dlist_append(DList* dest, void* src) {
-    dlist_check_resz(dest, 1);
+    dlist_check_resz(dest);
 
     dest->buf[dest->ln] = src;
-    dest->ln += 1;
+    dest->ln++;
 }
diff --git a/src/include/dlist.h b/src/include/dlist.h
index 0c8a8ee..dd57e36 100644
--- a/src/include/dlist.h
+++ b/src/include/dlist.h
@@ -3,7 +3,7 @@
 
 #include <stdlib.h>
 
-#define DLIST_INITSZ 128
+#define DLIST_INITSZ 128 * sizeof(void*)
 
 typedef struct {
     void** buf; // The buffer containing the list.
diff --git a/test/test_dlist.c b/test/test_dlist.c
new file mode 100644
index 0000000..f840125
--- /dev/null
+++ b/test/test_dlist.c
@@ -0,0 +1,41 @@
+#include "../src/include/dlist.h"
+#include "Unity/src/unity.h"
+
+void setUp() {};
+void tearDown() {};
+
+void test_dlist_init() {
+    DList* dlist = dlist_init();
+    TEST_ASSERT_EQUAL(0, dlist->ln);
+    TEST_ASSERT_EQUAL(DLIST_INITSZ, dlist->sz);
+}
+
+void test_dlist_append() {
+    DList* dlist;
+
+    // Test simple appending.
+    dlist = dlist_init();
+    int* n = malloc(sizeof(int));
+    *n = 1;
+    dlist_append(dlist, n);
+
+    TEST_ASSERT_EQUAL(n, dlist->buf[0]);
+    TEST_ASSERT_EQUAL(1, dlist->ln);
+
+    dlist_destroy(dlist);
+
+    // Test buffer doubling.
+    dlist = dlist_init();
+
+    for (int i = 0; i < 129; i++) dlist_append(dlist, &i);
+
+    TEST_ASSERT_EQUAL(129, dlist->ln);
+    TEST_ASSERT_EQUAL(DLIST_INITSZ*2, dlist->sz);
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_dlist_init);
+    RUN_TEST(test_dlist_append);
+    return UNITY_END();
+}