zig/std/list.zig

79 lines
2.2 KiB
Zig

const debug = @import("debug.zig");
const assert = debug.assert;
const mem = @import("mem.zig");
const Allocator = mem.Allocator;
pub fn List(comptime T: type) -> type{
struct {
const Self = this;
/// Use toSlice instead of slicing this directly, because if you don't
/// specify the end position of the slice, this will potentially give
/// you uninitialized memory.
items: []T,
len: usize,
allocator: &Allocator,
pub fn init(allocator: &Allocator) -> Self {
Self {
.items = []T{},
.len = 0,
.allocator = allocator,
}
}
pub fn deinit(l: &Self) {
l.allocator.free(l.items);
}
pub fn toSlice(l: &Self) -> []T {
return l.items[0...l.len];
}
pub fn toSliceConst(l: &const Self) -> []const T {
return l.items[0...l.len];
}
pub fn append(l: &Self, item: &const T) -> %void {
const new_item_ptr = %return l.addOne();
*new_item_ptr = *item;
}
pub fn resize(l: &Self, new_len: usize) -> %void {
%return l.ensureCapacity(new_len);
l.len = new_len;
}
pub fn ensureCapacity(l: &Self, new_capacity: usize) -> %void {
var better_capacity = l.items.len;
if (better_capacity >= new_capacity) return;
while (true) {
better_capacity += better_capacity / 2 + 8;
if (better_capacity >= new_capacity) break;
}
l.items = %return l.allocator.realloc(T, l.items, better_capacity);
}
pub fn addOne(l: &Self) -> %&T {
const new_length = l.len + 1;
%return l.ensureCapacity(new_length);
const result = &l.items[l.len];
l.len = new_length;
return result;
}
}
}
test "basicListTest" {
var list = List(i32).init(&debug.global_allocator);
defer list.deinit();
{var i: usize = 0; while (i < 10; i += 1) {
%%list.append(i32(i + 1));
}}
{var i: usize = 0; while (i < 10; i += 1) {
assert(list.items[i] == i32(i + 1));
}}
}