From db7277df5ed4a0951698697b62afa823c3ba0d72 Mon Sep 17 00:00:00 2001
From: "Douglas B. Rumbaugh" <doug@douglasrumbaugh.com>
Date: Sun, 2 Nov 2025 13:23:50 -0500
Subject: Intial commit: No free list management yet

---
 include/alloc.h     | 38 ++++++++++++++++++++++++++++++++++++++
 include/constants.h | 18 ++++++++++++++++++
 include/free_list.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+)
 create mode 100644 include/alloc.h
 create mode 100644 include/constants.h
 create mode 100644 include/free_list.h

(limited to 'include')

diff --git a/include/alloc.h b/include/alloc.h
new file mode 100644
index 0000000..cdbdb37
--- /dev/null
+++ b/include/alloc.h
@@ -0,0 +1,38 @@
+/*
+ * include/alloc.h
+ *
+ * Primary header for liballoc API
+ * CISC 301 -- Operating Systems, Project 3
+ *
+ * Copyright (C) 2025  Douglas B. Rumbaugh <dbrumbaugh@harrisburgu.edu>
+ * 
+ * Distributed under the Modified BSD License
+ *
+ */
+#ifndef H_LIBALLOC
+#define H_LIBALLOC
+
+#include <assert.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "constants.h"
+#include "free_list.h"
+
+/*
+ * Returns a pointer to a new region of memory of the specified
+ * size, or NULL if no memory is available.
+ */
+void *allocate(size_t);
+
+/*
+ * Release a block of memory previous allocated using allocate(). If the
+ * input pointer was not returned by allocate(), then the behavior of
+ * this function is undefined.
+ *
+ * Accessing a pointer that has been previous passed to this function is
+ * undefined behavior.
+ */
+void release(void *);
+
+#endif
diff --git a/include/constants.h b/include/constants.h
new file mode 100644
index 0000000..7d88060
--- /dev/null
+++ b/include/constants.h
@@ -0,0 +1,18 @@
+/*
+ * include/constants.h
+ *
+ * Configuration constant values for liballoc
+ * CISC 301 -- Operating Systems, Project 3
+ *
+ * Copyright (C) 2025  Douglas B. Rumbaugh <dbrumbaugh@harrisburgu.edu>
+ * 
+ * Distributed under the Modified BSD License
+ *
+ */
+#ifndef H_LIBALLOC_CONST
+#define H_LIBALLOC_CONST
+
+#define MAGIC_NUMBER 0x123456789
+#define ALIGNMENT 16
+
+#endif
diff --git a/include/free_list.h b/include/free_list.h
new file mode 100644
index 0000000..887167b
--- /dev/null
+++ b/include/free_list.h
@@ -0,0 +1,52 @@
+/*
+ * include/free_list.h
+ *
+ * Free list management routines for liballoc
+ * CISC 301 -- Operating Systems, Project 3
+ *
+ * Copyright (C) 2025  Douglas B. Rumbaugh <dbrumbaugh@harrisburgu.edu>
+ * 
+ * Distributed under the Modified BSD License
+ *
+ */
+#ifndef H_LIBALLOC_FREELIST
+#define H_LIBALLOC_FREELIST
+
+#include <stdlib.h>
+
+#include "constants.h"
+
+typedef struct free_nd {
+  size_t size;
+  struct free_nd *next;
+} free_nd;
+
+/*
+ * Scans the specified free list for the first node with >= the
+ * specified size and returns a pointer to it. If no such node can
+ * be found, returns NULL.
+ */
+free_nd *fl_find_first_fit(free_nd *free_list, size_t size);
+
+/*
+ * Split the specified free list node based on the required size, while
+ * maintaining alignment, and update the free list accordingly. If the
+ * specified node cannot be split (e.g., it's an exact match for size
+ * within alignment restrictions), simply remove it from the list.
+ *
+ * Returns a pointer to the region of memory removed from the list.
+ */
+void *fl_split_node(free_nd *free_list, free_nd *nd, size_t size);
+
+/*
+ * Scans the free list for adjacent nodes and merges them together
+ */
+void fl_coalesce_nodes(free_nd *free_list);
+
+/*
+ * Scans the free list for the correct location for the specified
+ * pointer, and link it into the list at that point.
+ */
+void fl_add_node(free_nd *free_list, void *ptr);
+
+#endif
-- 
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