From 55632d07eb170244cf6a0688ecd62b12d29918cc Mon Sep 17 00:00:00 2001
From: rhuibertsjr <rhuibertsjr@gmail.com>
Date: Sun, 21 Apr 2024 11:11:28 +0200
Subject: [PATCH] Added: base.h and arena allocator implementation

---
 docs/CHANGELOG |  4 ++++
 src/arena.c    | 40 ++++++++++++++++++++++++++++++++++++++++
 src/arena.h    | 31 +++++++++++++++++++++++++++++++
 src/base.h     | 27 +++++++++++++++++++++++++++
 src/main.c     |  5 +++++
 5 files changed, 107 insertions(+)
 create mode 100644 src/arena.c
 create mode 100644 src/arena.h
 create mode 100644 src/base.h

diff --git a/docs/CHANGELOG b/docs/CHANGELOG
index c703d66..02073d0 100644
--- a/docs/CHANGELOG
+++ b/docs/CHANGELOG
@@ -1,3 +1,7 @@
+21-04-2024  René Huiberts  <rhuibertsjr@gmail.com>
+
+	Added: base.h and arena allocator implementation
+
 21-04-2024  René Huiberts  <rhuibertsjr@gmail.com>
 
 	Added: project layout
diff --git a/src/arena.c b/src/arena.c
new file mode 100644
index 0000000..ea5a11c
--- /dev/null
+++ b/src/arena.c
@@ -0,0 +1,40 @@
+internal Arena *
+arena_initialize(u64 size)
+{
+  Arena *result = 0;
+
+  void *backing_buffer = malloc(size);
+
+  if (backing_buffer != NULL)
+  {
+    result = (Arena*) backing_buffer;
+
+    result->buffer = backing_buffer;
+    result->offset = sizeof(Arena);
+    result->size   = sizeof(Arena) + size;
+  }
+
+  return result;
+}
+
+internal void *
+arena_allocate(Arena *arena, u64 size)
+{
+  void *result = 0;
+
+  if (arena->offset + size <= arena->size)
+  {
+    result = (void*)((u64) arena->buffer + (u64) arena->offset);
+    arena->offset += size;
+
+    memset(result, 0, size);
+  }
+
+  return result;
+}
+
+internal void
+arena_release(Arena *arena)
+{
+  arena->offset = 0;
+}
diff --git a/src/arena.h b/src/arena.h
new file mode 100644
index 0000000..b07866f
--- /dev/null
+++ b/src/arena.h
@@ -0,0 +1,31 @@
+#ifndef ARENA_H
+#define ARENA_H
+
+typedef struct Arena Arena;
+struct Arena {
+  u64 *buffer;
+  u64 offset;
+  u64 size;
+};
+
+internal Arena * arena_initialize(u64 size);
+
+internal void * arena_allocate(Arena *arena, u64 size);
+internal void   arena_release(Arena *arena);
+
+//= rhjr: arena helpers
+
+#define arena_push_array(arena, type, count) \
+  (type*) arena_allocate((arena), sizeof(type) * (count))
+
+#define arena_push(arena, type) \
+  (type*) arena_allocate((arena), sizeof(type))
+
+//= rhjr: memory helpers
+
+#define memory_zero(s,z)       memset((s), 0, (z))
+#define memory_zero_struct(s)  memory_zero((s), sizeof(*(s)))
+
+#define memory_copy(dst, src, length) memmove((dst), (src), (length))
+
+#endif // ARENA_H
diff --git a/src/base.h b/src/base.h
new file mode 100644
index 0000000..6b578c1
--- /dev/null
+++ b/src/base.h
@@ -0,0 +1,27 @@
+#ifndef BASE_H
+#define BASE_H
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define internal static
+
+typedef uint8_t  u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef int8_t  i8;
+typedef int16_t i16;
+typedef int32_t i32;
+typedef int64_t i64;
+
+#define KB(b) ((b) << 10)
+#define MB(b) ((b) << 20)
+
+#define STATEMENT(S) do{ S } while(0)
+#define ASSERT(c) STATEMENT( if (!(c)){ (*(volatile int*)0 = 0); } )
+
+#endif // BASE_H
diff --git a/src/main.c b/src/main.c
index 77bc677..3731b84 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,3 +1,8 @@
+#include "base.h"
+#include "arena.h"
+
+#include "arena.c"
+
 int
 main(void)
 {