From 69dc1dcb457089a94792fa255d992a70ccf487bb Mon Sep 17 00:00:00 2001
From: Squibid <me@zacharyscheiman.com>
Date: Sat, 15 Nov 2025 21:39:57 -0500
Subject: [PATCH] feat(ll)!: add new ll function and rename insert

ds_*ll_insert -> ds_*ll_append to better reflect what it does and there
is now ds_*ll_add to add data anywhere in the ll.
---
 README.md |  4 ++--
 ds.c      | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 ds.h      | 32 ++++++++++++++++++++++-----
 test.c    | 18 ++++++++++-----
 4 files changed, 104 insertions(+), 16 deletions(-)

diff --git a/README.md b/README.md
index e8a3568..650a3c6 100644
--- a/README.md
+++ b/README.md
@@ -8,8 +8,8 @@ Example of working with a singly linked list (sll):
 char *a = "one";
 char *b = "two";
 ds_sll_t *ll = ds_sll_init();
-ds_sll_insert(ll, a); // [ "one" ]
-ds_sll_insert(ll, b); // [ "one", "two" ]
+ds_sll_append(ll, a); // [ "one" ]
+ds_sll_append(ll, b); // [ "one", "two" ]
 ds_ll_foreach(ds_sll_t, ll) {
     puts(cur->data);
     // one
diff --git a/ds.c b/ds.c
index 661b482..25f36b3 100644
--- a/ds.c
+++ b/ds.c
@@ -40,7 +40,67 @@ ds_dll_t
 }
 
 int
-ds_sll_insert(ds_sll_t *ll, void *data)
+ds_sll_add(ds_sll_t **ll, void *data, unsigned x)
+{
+  int i;
+  ds_sll_t *cur, *prev, *new;
+  if (!ll || !data) {
+    return -1;
+  }
+
+  for (i = 0, cur = *ll; cur; prev = cur, cur = cur->next, i++) {
+    if (i == x) {
+      if (!cur->data) {
+        cur->data = data;
+        return 0;
+      }
+      new = ds_sll_new_node(data);
+      new->next = cur;
+      if (i == 0) {
+        *ll = new;
+      } else {
+        prev->next = new;
+      }
+      return 0;
+    }
+  }
+
+  return -1;
+}
+
+int
+ds_dll_add(ds_dll_t **ll, void *data, unsigned x)
+{
+  int i;
+  ds_dll_t *cur, *new;
+  if (!ll || !data) {
+    return -1;
+  }
+
+  for (i = 0, cur = *ll; cur; cur = cur->next, i++) {
+    if (i == x) {
+      if (!cur->data) {
+        cur->data = data;
+        return 0;
+      }
+      new = ds_dll_new_node(data);
+      new->next = cur;
+      new->prev = cur->prev;
+      cur->prev = new;
+      if (i == 0) {
+        *ll = new;
+      } else {
+        cur->prev->next = new;
+      }
+      return 0;
+    }
+  }
+
+  return -1;
+}
+
+int
+ds_sll_append(ds_sll_t *ll, void *data)
 {
   if (!ll || !data) {
     return -1;
@@ -60,7 +120,7 @@ ds_sll_insert(ds_sll_t *ll, void *data)
 }
 
 int
-ds_dll_insert(ds_dll_t *ll, void *data)
+ds_dll_append(ds_dll_t *ll, void *data)
 {
   if (!ll || !data) {
     return -1;
@@ -241,7 +301,7 @@ ds_hmp_insert(ds_hmp_t *hmp, char *key, void *data)
 
   /* get the ll and put the data into it */
   ll = hmp->data[hash_pos];
-  if (ds_sll_insert(ll, kv) != 0) {
+  if (ds_sll_append(ll, kv) != 0) {
     return -1;
   }
 
diff --git a/ds.h b/ds.h
index a8fbb3f..93e99db 100644
--- a/ds.h
+++ b/ds.h
@@ -55,24 +55,46 @@ ds_sll_t *ds_sll_new_node(void *data);
 ds_dll_t *ds_dll_new_node(void *data);
 
 /**
- * @brief data to insert into a singly linked list. This will use
+ * @brief data to add at x of a singly linked list. This will use
  * ds_sll_new_node to create the node for you.
  *
  * @param ll singly linked list
  * @param data data you want to add
+ * @param x the position to add it at
  * @return 0 on success
  */
-int ds_sll_insert(ds_sll_t *ll, void *data);
+int ds_sll_add(ds_sll_t **ll, void *data, unsigned x);
 
 /**
- * @brief data to insert into a doubly linked list. This will use
- * ds_sll_new_node to create the node for you.
+ * @brief data to add at x of a doubly linked list. This will use
+ * ds_dll_new_node to create the node for you.
  *
  * @param ll doubly linked list
  * @param data data you want to add
+ * @param x the position to add it at
  * @return 0 on success
  */
-int ds_dll_insert(ds_dll_t *ll, void *data);
+int ds_dll_add(ds_dll_t **ll, void *data, unsigned x);
+
+/**
+ * @brief data to append to the end of a singly linked list. This will use
+ * ds_sll_new_node to create the node for you.
+ *
+ * @param ll singly linked list
+ * @param data data you want to append
+ * @return 0 on success
+ */
+int ds_sll_append(ds_sll_t *ll, void *data);
+
+/**
+ * @brief data to append to the end of a doubly linked list. This will use
+ * ds_dll_new_node to create the node for you.
+ *
+ * @param ll doubly linked list
+ * @param data data you want to append
+ * @return 0 on success
+ */
+int ds_dll_append(ds_dll_t *ll, void *data);
 
 /**
  * @brief remove an index from a singly linked list
diff --git a/test.c b/test.c
index 2e99a9a..dc84bc9 100644
--- a/test.c
+++ b/test.c
@@ -30,29 +30,35 @@ int
 main(int argc, char *argv[])
 {
   test("sll",
-    char *a = "one";
+    char *a = "a";
+    char *b = "b";
 
     ds_sll_t *tmp;
     it("creates a new linked list", tmp = ds_sll_init());
     free(tmp);
 
     ds_sll_t *ll = ds_sll_new_node(a);
-    it("inserts an invalid item", ds_sll_insert(ll, NULL) == -1);
+    it("appends an invalid item", ds_sll_append(ll, NULL) == -1);
     it("removes an invalid index", ds_sll_remove(&ll, 1234) == NULL);
-    it("removes an item", a == ds_sll_remove(&ll, 0));
+    it("adds an item to the beginning", ds_sll_add(&ll, b, 0) == 0);
+    it("removes an item", b == ds_sll_remove(&ll, 0));
+    ds_sll_remove(&ll, 0);
   );
 
   test("dll",
-    char *a = "one";
+    char *a = "a";
+    char *b = "b";
 
     ds_dll_t *tmp;
     it("creates a new linked list", tmp = ds_dll_init());
     free(tmp);
 
     ds_dll_t *ll = ds_dll_new_node(a);
-    it("inserts an invalid item", ds_dll_insert(ll, NULL) == -1);
+    it("appends an invalid item", ds_dll_append(ll, NULL) == -1);
     it("removes an invalid index", ds_dll_remove(&ll, 1234) == NULL);
-    it("removes an item", a == ds_dll_remove(&ll, 0));
+    it("adds an item to the beginning", ds_dll_add(&ll, b, 0) == 0);
+    it("removes an item", b == ds_dll_remove(&ll, 0));
+    ds_dll_remove(&ll, 0);
   );
 
   test("hmp",