motiejus/zig
1
Fork 0
Code Releases Activity

Implement clone with initCapacity and appendSliceAssumeCapacity

Browse Source 
`ArrayList.ensureTotalCapacityPrecise` uses `Allocator.reallocAtLeast` under
the hood, which can return more than `new_capacity` bytes if `alignment
!= @alignOf(T)`. This implementation of `clone` assures that
the case of `ensureTotalCapacityPrecise` is handled correctly.

Thanks @Vexu and @squeek502 for pointing this out.
This commit is contained in:
John Schmidt
2021-12-13 15:01:05 +01:00
committed by Veikka Tuominen
parent d86b8663fc
commit f04007028f
1 changed files with 8 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
lib/std/array_list.zig
View File

@@ -110,14 +110,9 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
/// Creates a copy of this ArrayList, using the same allocator.
pub fn clone(self: *Self) !Self {
var items_copy = try self.allocator.alloc(T, self.capacity);
mem.copy(T, items_copy, self.items);
items_copy.len = self.items.len;
return Self{
.items = items_copy,
.capacity = self.capacity,
.allocator = self.allocator,
};
var cloned = try ArrayList(T).initCapacity(self.allocator, self.capacity);
cloned.appendSliceAssumeCapacity(self.items);
return cloned;
}
/// Insert `item` at index `n` by moving `list[n .. list.len]` to make room.
@@ -503,13 +498,9 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) typ
/// Creates a copy of this ArrayList.
pub fn clone(self: *Self, allocator: Allocator) !Self {
var items_copy = try allocator.alloc(T, self.capacity);
mem.copy(T, items_copy, self.items);
items_copy.len = self.items.len;
return Self{
.items = items_copy,
.capacity = self.capacity,
};
var cloned = try ArrayListUnmanaged(T).initCapacity(allocator, self.capacity);
cloned.appendSliceAssumeCapacity(self.items);
return cloned;
}
/// Insert `item` at index `n`. Moves `list[n .. list.len]`
@@ -837,8 +828,8 @@ test "std.ArrayList/ArrayListUnmanaged.clone" {
defer cloned.deinit();
try testing.expectEqualSlices(i32, array.items, cloned.items);
try testing.expectEqual(array.capacity, cloned.capacity);
try testing.expectEqual(array.allocator, cloned.allocator);
try testing.expect(cloned.capacity >= array.capacity);
array.deinit();
@@ -856,7 +847,7 @@ test "std.ArrayList/ArrayListUnmanaged.clone" {
defer cloned.deinit(a);
try testing.expectEqualSlices(i32, array.items, cloned.items);
try testing.expectEqual(array.capacity, cloned.capacity);
try testing.expect(cloned.capacity >= array.capacity);
array.deinit(a);