checkpoint

1 files changed, 69 insertions, 0 deletions

diff --git a/library/arena.h b/library/arena.h
new file mode 100644
index 0000000..330023e
--- /dev/null
+++ b/library/arena.h
@@ -0,0 +1,69 @@
+#ifndef ARENA_H
+#define ARENA_H
+
+#include "base.h"
+
+/**
+ * Arena Helper macro's
+ * */
+
+#define MIN(a, b) (((a) < (b)) ? (a) : (b))
+#define MAX(a, b) (((a) > (b)) ? (a) : (b))
+#define ALIGN_UP_POW2(n, p) (((u64)(n) + ((u64)(p) - 1)) & (~((u64)(p) - 1)))
+
+
+
+/*
+ * Represents a disk partition with major/minor device numbers and block count.
+ */
+
+/**
+ * replacing malloc/free with arena allocaters
+ *
+ * */
+
+#define ARENA_BASE_POS (sizeof(mem_arena))
+// void * for the size of a pointer on the machine, 64/32bit comp
+#define ARENA_ALIGN (sizeof(void *))
+
+
+static inline u64 KiB(u64 n) { return n << 10; }
+static inline u64 MiB(u64 n) { return n << 20; }
+static inline u64 GiB(u64 n) { return n << 30; }
+
+typedef struct mem_arena mem_arena;
+
+
+struct mem_arena 
+{
+  u64 capacity;
+  u64 pos;
+} ;
+
+// arena prototypes
+mem_arena *
+arena_create(u64 capacity);
+// make it a void pointer to allow implicit conversion
+void
+arena_destroy(mem_arena *arena);
+
+void *
+arena_push(mem_arena *arena, u64 size, b32 non_zero);
+
+void
+arena_pop(mem_arena *arena, u64 size);
+
+void
+arena_pop_to(mem_arena *arena, u64 pos);
+
+void
+arena_clear(mem_arena *arena);
+
+
+#define PUSH_STRUCT(arena, T) (T *)arena_push((arena), sizeof(T), 0)
+#define PUSH_STRUCT_NZ(arena, T) (T *)arena_push((arena), sizeof(T), 1)
+#define PUSH_ARRAY(arena, T, n) (T *)arena_push((arena), sizeof(T) * (n), 0)
+#define PUSH_ARRAY_NZ(arena, T, n) (T *)arena_push((arena), sizeof(T) * (n), 1)
+
+
+#endif