refactor: introduce reference counting pointer

1 files changed, 47 insertions, 0 deletions

diff --git a/src/rc.zig b/src/rc.zig
new file mode 100644
index 0000000..0c16023
--- /dev/null
+++ b/src/rc.zig
@@ -0,0 +1,47 @@
+const std = @import("std");
+
+pub fn Rc(comptime T: type) type {
+    const Cell = struct {
+        value: T,
+        ref_count: usize,
+    };
+
+    return struct {
+        const Self = @This();
+
+        allocator: std.mem.Allocator,
+        ptr: *Cell,
+
+        pub fn init(allocator: std.mem.Allocator) !Self {
+            const ptr = try allocator.create(Cell);
+            ptr.ref_count = 1;
+            return .{
+                .allocator = allocator,
+                .ptr = ptr,
+            };
+        }
+
+        pub fn deinit(self: *const Self) void {
+            self.ptr.ref_count -= 1;
+            if (self.ptr.ref_count == 0) {
+                self.allocator.destroy(self.ptr);
+            }
+        }
+
+        pub fn clone(self: *const Self) Self {
+            self.ptr.ref_count += 1;
+            return .{
+                .allocator = self.allocator,
+                .ptr = self.ptr,
+            };
+        }
+
+        pub fn get(self: *const Self) *const T {
+            return &self.ptr.value;
+        }
+
+        pub fn get_mut(self: *Self) *T {
+            return &self.ptr.value;
+        }
+    };
+}