checkpoint

1 files changed, 53 insertions, 0 deletions

diff --git a/arena.h b/arena.h
new file mode 100644
index 0000000..f3d21d7
--- /dev/null
+++ b/arena.h
@@ -0,0 +1,53 @@
+#ifndef ARENA_H
+#define ARENA_H
+
+#include <sys/mman.h>
+#include <stdint.h>
+#include "types.h"
+
+// Arena Allocator
+typedef struct {
+    void* addr;
+    u64 size;
+    u64 pos;
+} Arena;
+#define PushArray(arena, type, count) (type*)ArenaPush((arena), sizeof(type) * (count))
+#define PushArrayZero(arena, type, count) (type*)ArenaPushZero((arena), sizeof(type) * (count))
+#define PushStruct(arena, type) PushArray((arena), (type), 1)
+#define PushStructZero(arena, type) PushArrayZero((arena), (type), 1)
+
+void ArenaAlloc(Arena* arena, u64 size);
+void ArenaRelease(Arena* arena);
+void* ArenaPush(Arena* arena, u64 size);
+
+#endif // ARENA_H
+
+#ifdef ARENA_IMPL
+
+// Returns arena in case of success, or 0 if it failed to alllocate the memory
+void
+ArenaAlloc(Arena* arena, u64 size)
+{
+    arena->addr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+    Assert(arena->addr != MAP_FAILED);
+    arena->pos = 0;
+    arena->size = size;
+}
+
+void
+ArenaRelease(Arena* arena)
+{
+    munmap(arena->addr, arena->size);
+}
+
+void*
+ArenaPush(Arena* arena, u64 size)
+{
+    u8* mem;
+    mem = (u8*)arena->addr + arena->pos;
+    arena->pos += size;
+    Assert(arena->pos <= arena->size);
+    return mem;
+}
+
+#endif // ARENA_IMPL