From e7e2829a631903dab6cb03542cb8338855dd0191 Mon Sep 17 00:00:00 2001
From: tijani <tijani@tijanilawal.com>
Date: Mon, 5 Aug 2024 01:34:05 -0500
Subject: [PATCH] Definitions for arena memory management.

---
 src/base/base_arena.h | 58 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 src/base/base_arena.h

diff --git a/src/base/base_arena.h b/src/base/base_arena.h
new file mode 100644
index 0000000..29943a7
--- /dev/null
+++ b/src/base/base_arena.h
@@ -0,0 +1,58 @@
+#ifndef BASE_ARENA_H
+#define BASE_ARENA_H
+
+// Constants
+#define ARENA_HEADER_SIZE 64
+
+// Types
+typedef u32 ArenaFlags;
+enum { ArenaFlag_NoChain = (1 << 0); ArenaFlag_LargePages = (1 << 1); };
+
+typedef struct ArenaParams ArenaParams;
+struct ArenaParams {
+  ArenaFlags flags;
+  u64 reserve_size;
+  u64 commite_size;
+  void *optional_backing_buffer; // NOTE(tijani): ??
+};
+
+typedef struct Arena Arena;
+struct Arena {
+  Arena *previous; // Previous arena in the chain
+  Arena *current;  // Current arena in the chain
+  ArenaFlags flags;
+  u32 commit_size;
+  u64 reserve_size;
+  u64 base_position;
+  u64 position;
+  u64 commit;
+  u64 reserve;
+};
+
+typedef struct Temp Temp;
+struct Temp {
+  Arena *arena;
+  u64 position;
+};
+
+// creation, destruction
+internal Arena *arena_alloc_(ArenaParams *params);
+#define arena_alloc(...) arena_alloc_(&(ArenaParams){.reserve_size = MB(64), .commit_size = KB(64), __VA_ARGS__})
+internal void arena_releas(Arena *arena);
+
+// push, pop operations
+internal void *arena_psuh(Arena *arena, u64 size, u64 align);
+internal u64 arena_position(Arena *arena);
+internal void arena_pop_to(Arena *arena, u64 position);
+internal void arena_clear(Arena *arena);
+internal void arena_pop(Arena *arena, u64 amount);
+#define push_array_no_zero_aligned(a, T, c, align) (T *)arena_push((a), sizeof(T) * (c), (align))
+#define push_array_aligned(a, T, c, align) (T *)MemoryZero(push_array_no_zero_aligned(a, T, c, align), sizeof(T) * (c))
+#define push_array_no_zero(a, T, c) push_array_no_zero_aligned(a, T, c, Max(8, Align_Of(T)))
+#define push_array(a, T, c) push_array_aligned(a, T, c, Max(8, Align_Of(T)))
+
+// Temp
+internal Temp temp_begin(Arena *arena);
+internal void temp_end(Temp temp);
+
+#endif // BASE_ARENA_H