Initial implementation of free list functions

Implemented (but haven't tested) adding nodes
to the free list and coalescing them.

1 files changed, 42 insertions, 5 deletions

diff --git a/src/free_list.c b/src/free_list.c
index c1dd79c..5ea5f2e 100644
--- a/src/free_list.c
+++ b/src/free_list.c
@@ -5,18 +5,55 @@
  * CISC 301 -- Operating Systems, Project 3
  *
  * Copyright (C) 2025  Douglas B. Rumbaugh <dbrumbaugh@harrisburgu.edu>
- * 
+ *
  * Distributed under the Modified BSD License
  *
  */
 #include "free_list.h"
 
-free_nd *fl_find_first_fit(free_nd *free_list, size_t size) { return NULL; }
+free_nd *fl_find_first_fit(free_nd *free_list, size_t size) {
+  for (free_nd *nd = free_list; nd; nd = nd->next) {
+    if (nd->size >= size) {
+      return nd;
+    }
+  }
 
-void *fl_split_node(free_nd *free_list, free_nd *nd, size_t size) {
   return NULL;
 }
 
-void fl_coalesce_nodes(free_nd *free_list) {}
+void *fl_split_node(free_nd **free_list, free_nd *nd, size_t size) {
+  return NULL;
+}
+
+void fl_coalesce_nodes(free_nd *free_list) {
+  for (free_nd *nd = free_list; nd; nd = nd->next) {
+    if ((size_t)nd + sizeof(header) == (size_t)nd->next) {
+      nd->size += sizeof(header) + nd->next->size;
+      nd->next = nd->next->next;
+    }
+  }
+}
 
-void fl_add_node(free_nd *free_list, void *ptr) {}
+void fl_add_node(free_nd **free_list, void *ptr) {
+  free_nd *new_nd = (free_nd *)ptr;
+  new_nd->next = NULL;
+  new_nd->size = ((header *)ptr - sizeof(header))->size;
+
+  if (!(*free_list)) {
+    *free_list = new_nd;
+    return;
+  }
+
+  for (free_nd *nd = *free_list; nd; nd = nd->next) {
+    if (nd->next > new_nd) {
+      new_nd->next = nd->next;
+      nd->next = new_nd;
+      return;
+    }
+  }
+
+  /* if we get here, then the new node must go before the current head */
+  new_nd->next = *free_list;
+  *free_list = new_nd;
+  return;
+}