free_list: partial split implementation

Implemented enough of split to get basic free
list reuse working. Also updated the allocate()
function to return the output of split when it is
called.

2 files changed, 19 insertions, 3 deletions

diff --git a/src/alloc.c b/src/alloc.c
index dd1c8aa..3f805db 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -53,7 +53,7 @@ void *allocate(size_t size) {
   /* first check for a suitable memory block on the free list */
   free_nd *nd = fl_find_first_fit(free_list, size);
   if (nd) {
-    void *return_region = fl_split_node(&free_list, nd, size);
+    return fl_split_node(&free_list, nd, size);
   }
 
   /*
diff --git a/src/free_list.c b/src/free_list.c
index 31244fb..ee9e571 100644
--- a/src/free_list.c
+++ b/src/free_list.c
@@ -21,8 +21,24 @@ free_nd *fl_find_first_fit(free_nd *free_list, size_t size) {
   return NULL;
 }
 
-void *fl_split_node(free_nd **free_list, free_nd *nd, size_t size) {
-  return NULL;
+void *fl_split_node(free_nd **free_list, free_nd *split_nd, size_t size) {
+  /* for now, we'll just remove the node from the free list */
+
+  if (*free_list == split_nd) {
+    *free_list = (*free_list)->next;
+  }
+
+  for (free_nd *nd = *free_list; nd; nd = nd->next) {
+    if (nd->next == split_nd) {
+      /* 
+       * split_nd is not null, so we know that nd->next is 
+       * also not null here 
+       */
+      nd->next = nd->next->next;
+    }
+  }
+
+  return split_nd;
 }
 
 void fl_coalesce_nodes(free_nd *free_list) {