From 6b99bb6f7f63e8417042220a6c02eb43d48803d5 Mon Sep 17 00:00:00 2001
From: Talha Qamar <qamartalha@proton.me>
Date: Fri, 31 Jan 2025 21:17:28 +0500
Subject: [PATCH] Added Arena Allocator (crime against humanity)
---
src/lily/alloc/arena.hb | 62 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)
create mode 100644 src/lily/alloc/arena.hb
diff --git a/src/lily/alloc/arena.hb b/src/lily/alloc/arena.hb
new file mode 100644
index 0000000..908a059
--- /dev/null
+++ b/src/lily/alloc/arena.hb
@@ -0,0 +1,62 @@
+.{Config, Target, Type, log, collections: .{Vec}} := @use("../lib.hb");
+
+Allocation := struct {
+ ptr: ^u8,
+ len: uint,
+}
+
+ArenaAllocator := struct {
+ ptr: ^u8,
+ size: uint,
+ allocated: uint,
+
+ $new := fn(size: uint): Self {
+ allocated := idk
+ if size == 0 {
+ allocated = Target.page_size()
+ } else {
+ allocated = size
+ }
+ ptr := Target.alloc_zeroed(size)
+ return .(ptr, size, 0)
+ }
+ deinit := fn(self: ^Self): void {
+ match Target.current() {
+ .LibC => Target.dealloc(self.ptr),
+ .AbleOS => Target.dealloc(self.ptr, self.size),
+ }
+ log.debug("deinit: allocator")
+ }
+ alloc := fn(self: ^Self, $T: type, count: uint): ?^T {
+ if count * @sizeof(T) + self.allocated > self.size {
+ log.error("You allocated more memory on the arena than the arena had.");
+ die
+ }
+ allocation := self.ptr + self.allocated
+ self.allocated = self.allocated + count * @sizeof(T)
+ log.debug("allocated")
+ return @bitcast(allocation)
+ }
+ alloc_zeroed := fn(self: ^Self, $T: type, count: uint): ?^T {
+ return self.alloc(T, count)
+ }
+ realloc := fn(self: ^Self, $T: type, ptr: ^T, count: uint): ?^T {
+ log.error("Don't call realloc on the arena allocator");
+ die
+ }
+ dealloc := fn(self: ^Self, $T: type, ptr: ^T): void {
+ log.debug("freed")
+ }
+ _find_and_remove := fn(self: ^Self, ptr: ^u8): ?Allocation {
+ i := 0
+ loop if i == self.allocations.len() break else {
+ defer i += 1
+ alloced := self.allocations.get_unchecked(i)
+ if alloced.ptr == ptr {
+ _ = self.allocations.swap_remove(i)
+ return alloced
+ }
+ }
+ return null
+ }
+}