authorgravatar for jesse.rudolph@gmail.comJesse Rudolph <jesse.rudolph@gmail.com> 2020-06-02 11:12:26-05:00
committergravatar for jesse.rudolph@gmail.comJesse Rudolph <jesse.rudolph@gmail.com> 2020-06-02 17:00:01-05:00
logc0a0193c0a90f633d7a02bb8631f974ab5e2481e
treedb4e0743fcc84c9e09a5fb7b42a3258367403901
parent40a1cfed538c0a19993c3f5497d1ef18d46dac2b

add replaceRange() function to ArrayList

generalizes functionality of ArrayList.insertSlice() to overwrite a range of elements in the list and to grow or shrink the list as needed to accommodate size difference of the replacing slice and the range of existing elements.

1 files changed, 65 insertions(+), 0 deletions(-)

lib/std/array_list.zig+65
...@@ -108,6 +108,33 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {...@@ -108,6 +108,33 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
108 mem.copy(T, self.items[i .. i + items.len], items);108 mem.copy(T, self.items[i .. i + items.len], items);
109 }109 }
110110
111 /// Replace range of elements `list[start..start+len]` with `new_items`
112 /// grows list if `len < new_items.len`. may allocate
113 /// shrinks list if `len > new_items.len`
114 pub fn replaceRange(self: *Self, start: usize, len: usize, new_items: SliceConst) !void {
115 const after_range = start + len;
116 const range = self.items[start..after_range];
117
118 if (range.len == new_items.len)
119 mem.copy(T, range, new_items)
120 else if (range.len < new_items.len) {
121 const first = new_items[0..range.len];
122 const rest = new_items[range.len..];
123
124 mem.copy(T, range, first);
125 try self.insertSlice(after_range, rest);
126 } else {
127 mem.copy(T, range, new_items);
128 const after_subrange = start + new_items.len;
129
130 for (self.items[after_range..]) |item, i| {
131 self.items[after_subrange..][i] = item;
132 }
133
134 self.items.len -= len - new_items.len;
135 }
136 }
137
111 /// Extend the list by 1 element. Allocates more memory as necessary.138 /// Extend the list by 1 element. Allocates more memory as necessary.
112 pub fn append(self: *Self, item: T) !void {139 pub fn append(self: *Self, item: T) !void {
113 const new_item_ptr = try self.addOne();140 const new_item_ptr = try self.addOne();
...@@ -335,6 +362,15 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) typ...@@ -335,6 +362,15 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) typ
335 mem.copy(T, self.items[i .. i + items.len], items);362 mem.copy(T, self.items[i .. i + items.len], items);
336 }363 }
337364
365 /// Replace range of elements `list[start..start+len]` with `new_items`
366 /// grows list if `len < new_items.len`. may allocate
367 /// shrinks list if `len > new_items.len`
368 pub fn replaceRange(self: *Self, start: usize, len: usize, new_items: SliceConst) !void {
369 var managed = self.toManaged(allocator);
370 try managed.replaceRange(start, len, new_items);
371 self.* = managed.toUnmanaged();
372 }
373
338 /// Extend the list by 1 element. Allocates more memory as necessary.374 /// Extend the list by 1 element. Allocates more memory as necessary.
339 pub fn append(self: *Self, allocator: *Allocator, item: T) !void {375 pub fn append(self: *Self, allocator: *Allocator, item: T) !void {
340 const new_item_ptr = try self.addOne(allocator);376 const new_item_ptr = try self.addOne(allocator);
...@@ -657,6 +693,35 @@ test "std.ArrayList.insertSlice" {...@@ -657,6 +693,35 @@ test "std.ArrayList.insertSlice" {
657 testing.expect(list.items[0] == 1);693 testing.expect(list.items[0] == 1);
658}694}
659695
696test "std.ArrayList.replaceRange" {
697 var arena = std.heap.ArenaAllocator.init(testing.allocator);
698 defer arena.deinit();
699
700 const alloc = &arena.allocator;
701 const init = [_]i32{ 1, 2, 3, 4, 5 };
702 const new = [_]i32{ 0, 0, 0 };
703
704 var list_zero = ArrayList(i32).init(alloc);
705 var list_eq = ArrayList(i32).init(alloc);
706 var list_lt = ArrayList(i32).init(alloc);
707 var list_gt = ArrayList(i32).init(alloc);
708
709 try list_zero.appendSlice(&init);
710 try list_eq.appendSlice(&init);
711 try list_lt.appendSlice(&init);
712 try list_gt.appendSlice(&init);
713
714 try list_zero.replaceRange(1, 0, &new);
715 try list_eq.replaceRange(1, 3, &new);
716 try list_lt.replaceRange(1, 2, &new);
717 try list_gt.replaceRange(1, 4, &new);
718
719 testing.expectEqualSlices(i32, list_zero.items, &[_]i32{ 1, 0, 0, 0, 2, 3, 4, 5 });
720 testing.expectEqualSlices(i32, list_eq.items, &[_]i32{ 1, 0, 0, 0, 5 });
721 testing.expectEqualSlices(i32, list_lt.items, &[_]i32{ 1, 0, 0, 0, 4, 5 });
722 testing.expectEqualSlices(i32, list_gt.items, &[_]i32{ 1, 0, 0, 0 });
723}
724
660const Item = struct {725const Item = struct {
661 integer: i32,726 integer: i32,
662 sub_items: ArrayList(Item),727 sub_items: ArrayList(Item),