From b058cbe288c799bfdc4d186fc240c1a4a2db3046 Mon Sep 17 00:00:00 2001
From: Eric-Paul Ickhorn <ericp.ickhorn@gmail.com>
Date: Tue, 28 Nov 2023 21:25:20 +0100
Subject: [PATCH] Implemented an arena allocator

---
 code/inc/utility.h   | 21 +++++++++++++++-
 code/src/allocator.c | 57 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 code/src/allocator.c

diff --git a/code/inc/utility.h b/code/inc/utility.h
index 6c0a804..bee9745 100644
--- a/code/inc/utility.h
+++ b/code/inc/utility.h
@@ -47,4 +47,23 @@ void        pac_memory_copy             (void *destination, void *source, usz_t
 void        pac_memory_fill             (void *region, usz_t len_region, u8_t byte);
 void        pac_memory_zero             (void *region, usz_t len_region);
 
-#endif // Include Guard (TN_UTIL_TYPES_H)
\ No newline at end of file
+
+
+typedef struct pac_arena
+{
+    usz_t                   len_allocation;
+    usz_t                   offset;
+    void                   *allocation;
+    pac_arena_s            *continuation;
+
+} pac_arena_s;
+
+pac_arena_s     pac_create_arena            (usz_t size);
+void            pac_delete_arena            (pac_arena_s arena);
+
+void            pac_free_arena              (pac_arena_s *arena);
+pac_arena_s *   pac_new_arena               (usz_t size);
+
+void *          pac_arena_alloc             (pac_arena_s *arena, usz_t length);
+
+#endif // Include Guard (TN_UTIL_TYPES_H)
diff --git a/code/src/allocator.c b/code/src/allocator.c
new file mode 100644
index 0000000..0ded8bc
--- /dev/null
+++ b/code/src/allocator.c
@@ -0,0 +1,57 @@
+#include <utility.h>
+
+pac_arena_s pac_create_arena(usz_t size)
+{
+    pac_arena_s                 arena;
+    arena.len_allocation            = size;
+    arena.offset                    = 0;
+    arena.allocation                = malloc(size);
+    arena.continuation              = NULL;
+    return arena;
+}
+
+void pac_delete_arena(pac_arena_s arena)
+{
+    if(arena.continuation != NULL)
+    {
+        pac_free_arena(arena.continuation);
+    }
+    free(arena.allocation);
+}
+
+
+
+pac_arena_s * pac_new_arena(usz_t size)
+{
+    pac_arena_s                *arena               = malloc(sizeof(pac_arena_s) + size);
+    arena->len_allocation           = size;
+    arena->offset                   = 0;
+    arena->allocation               = arena + sizeof(pac_arena_s);
+    arena->continuation             = NULL;
+
+    return arena;
+}
+
+void pac_free_arena(pac_arena_s *arena)
+{
+    if(arena->continuation != NULL)
+    {
+        pac_free_arena(arena->continuation);
+    }
+    free(arena);
+}
+
+
+
+void * pac_arena_alloc(pac_arena_s *arena, usz_t length)
+{
+    if((arena->offset + length) > arena->len_allocation)
+    {
+        if(arena->continuation == NULL)
+            arena->continuation = pac_new_arena(length*2);
+        return pac_arena_alloc(arena->continuation, length);
+    }
+    void                       *block               = arena->allocation + arena->offset;
+    arena->offset                  += length;
+    return block;
+}