Add simple memory arena implementation

mem_arena/arena.c

@@ -0,0 +1,47 @@
+#include "arena.h"
+#include "../aliases.h"
+#include <stdlib.h>
+#include <string.h>
+
+bool arena_init(arena_t *arena, u64 capacity) {
+  arena->buf = (u8 *)malloc(capacity);
+  if (!(arena->buf)) {
+    return false;
+  }
+
+  arena->capacity = capacity;
+
+  arena->offset = arena->buf;
+
+  return true;
+}
+
+u8 *arena_alloc(arena_t *arena, u64 size) {
+  if (arena->offset + size >= arena->buf + arena->capacity) {
+    return NULL;
+  }
+
+  u8 *output = arena->offset;
+
+  arena->offset += size;
+
+  return output;
+}
+
+void arena_clear(arena_t *arena) {
+  memset(arena->buf, 0, arena->offset - arena->buf);
+
+  arena->offset = arena->buf;
+}
+
+void arena_free(arena_t *arena) {
+  arena->capacity = 0;
+
+  arena->offset = NULL;
+
+  if (arena->buf) {
+    free(arena->buf);
+  }
+
+  arena->buf = NULL;
+}

mem_arena/arena.h

@@ -0,0 +1,18 @@
+#ifndef ARENA_H
+#define ARENA_H
+
+#include "../aliases.h"
+#include <stdbool.h>
+
+typedef struct {
+  u64 capacity;
+  u8 *buf;
+  u8 *offset;
+} arena_t;
+
+bool arena_init(arena_t *arena, u64 capacity);
+u8 *arena_alloc(arena_t *arena, u64 size);
+void arena_clear(arena_t *arena);
+void arena_free(arena_t *arena);
+
+#endif // !ARENA_H