datastruct: move ArrayListPool from renderer/cell.zig

1 files changed, 44 insertions, 0 deletions

diff --git a/src/datastruct/array_list_pool.zig b/src/datastruct/array_list_pool.zig
new file mode 100644
index 000000000..72cf8d29f
--- /dev/null
+++ b/src/datastruct/array_list_pool.zig
@@ -0,0 +1,44 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+/// A pool of ArrayLists with methods for bulk operations.
+pub fn ArrayListPool(comptime T: type) type {
+    return struct {
+        const Self = ArrayListPool(T);
+        const ArrayListT = std.ArrayListUnmanaged(T);
+
+        // An array containing the lists that belong to this pool.
+        lists: []ArrayListT = &[_]ArrayListT{},
+
+        // The pool will be initialized with empty ArrayLists.
+        pub fn init(
+            alloc: Allocator,
+            list_count: usize,
+            initial_capacity: usize,
+        ) Allocator.Error!Self {
+            const self: Self = .{
+                .lists = try alloc.alloc(ArrayListT, list_count),
+            };
+
+            for (self.lists) |*list| {
+                list.* = try .initCapacity(alloc, initial_capacity);
+            }
+
+            return self;
+        }
+
+        pub fn deinit(self: *Self, alloc: Allocator) void {
+            for (self.lists) |*list| {
+                list.deinit(alloc);
+            }
+            alloc.free(self.lists);
+        }
+
+        /// Clear all lists in the pool.
+        pub fn reset(self: *Self) void {
+            for (self.lists) |*list| {
+                list.clearRetainingCapacity();
+            }
+        }
+    };
+}