zig/std/array_list.zig

376 lines
11 KiB
Zig

const std = @import("index.zig");
const debug = std.debug;
const assert = debug.assert;
const assertError = debug.assertError;
const mem = std.mem;
const Allocator = mem.Allocator;
pub fn ArrayList(comptime T: type) type {
return AlignedArrayList(T, @alignOf(T));
}
pub fn AlignedArrayList(comptime T: type, comptime A: u29) type {
return 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: []align(A) T,
len: usize,
allocator: *Allocator,
/// Deinitialize with `deinit` or use `toOwnedSlice`.
pub fn init(allocator: *Allocator) Self {
return Self{
.items = []align(A) T{},
.len = 0,
.allocator = allocator,
};
}
pub fn deinit(self: Self) void {
self.allocator.free(self.items);
}
pub fn toSlice(self: Self) []align(A) T {
return self.items[0..self.len];
}
pub fn toSliceConst(self: Self) []align(A) const T {
return self.items[0..self.len];
}
pub fn at(self: Self, i: usize) T {
return self.toSliceConst()[i];
}
/// Sets the value at index `i`, or returns `error.OutOfBounds` if
/// the index is not in range.
pub fn setOrError(self: Self, i: usize, item: T) !void {
if (i >= self.len) return error.OutOfBounds;
self.items[i] = item;
}
/// Sets the value at index `i`, asserting that the value is in range.
pub fn set(self: *Self, i: usize, item: T) void {
assert(i < self.len);
self.items[i] = item;
}
pub fn count(self: Self) usize {
return self.len;
}
/// ArrayList takes ownership of the passed in slice. The slice must have been
/// allocated with `allocator`.
/// Deinitialize with `deinit` or use `toOwnedSlice`.
pub fn fromOwnedSlice(allocator: *Allocator, slice: []align(A) T) Self {
return Self{
.items = slice,
.len = slice.len,
.allocator = allocator,
};
}
/// The caller owns the returned memory. ArrayList becomes empty.
pub fn toOwnedSlice(self: *Self) []align(A) T {
const allocator = self.allocator;
const result = allocator.alignedShrink(T, A, self.items, self.len);
self.* = init(allocator);
return result;
}
pub fn insert(self: *Self, n: usize, item: T) !void {
try self.ensureCapacity(self.len + 1);
self.len += 1;
mem.copyBackwards(T, self.items[n + 1 .. self.len], self.items[n .. self.len - 1]);
self.items[n] = item;
}
pub fn insertSlice(self: *Self, n: usize, items: []align(A) const T) !void {
try self.ensureCapacity(self.len + items.len);
self.len += items.len;
mem.copyBackwards(T, self.items[n + items.len .. self.len], self.items[n .. self.len - items.len]);
mem.copy(T, self.items[n .. n + items.len], items);
}
pub fn append(self: *Self, item: T) !void {
const new_item_ptr = try self.addOne();
new_item_ptr.* = item;
}
/// Removes the element at the specified index and returns it.
/// The empty slot is filled from the end of the list.
pub fn swapRemove(self: *Self, i: usize) T {
if (self.len - 1 == i) return self.pop();
const slice = self.toSlice();
const old_item = slice[i];
slice[i] = self.pop();
return old_item;
}
/// Removes the element at the specified index and returns it
/// or an error.OutOfBounds is returned. If no error then
/// the empty slot is filled from the end of the list.
pub fn swapRemoveOrError(self: *Self, i: usize) !T {
if (i >= self.len) return error.OutOfBounds;
return self.swapRemove(i);
}
pub fn appendSlice(self: *Self, items: []align(A) const T) !void {
try self.ensureCapacity(self.len + items.len);
mem.copy(T, self.items[self.len..], items);
self.len += items.len;
}
pub fn resize(self: *Self, new_len: usize) !void {
try self.ensureCapacity(new_len);
self.len = new_len;
}
pub fn shrink(self: *Self, new_len: usize) void {
assert(new_len <= self.len);
self.len = new_len;
}
pub fn ensureCapacity(self: *Self, new_capacity: usize) !void {
var better_capacity = self.items.len;
if (better_capacity >= new_capacity) return;
while (true) {
better_capacity += better_capacity / 2 + 8;
if (better_capacity >= new_capacity) break;
}
self.items = try self.allocator.alignedRealloc(T, A, self.items, better_capacity);
}
pub fn addOne(self: *Self) !*T {
const new_length = self.len + 1;
try self.ensureCapacity(new_length);
const result = &self.items[self.len];
self.len = new_length;
return result;
}
pub fn pop(self: *Self) T {
self.len -= 1;
return self.items[self.len];
}
pub fn popOrNull(self: *Self) ?T {
if (self.len == 0) return null;
return self.pop();
}
pub const Iterator = struct {
list: *const Self,
// how many items have we returned
count: usize,
pub fn next(it: *Iterator) ?T {
if (it.count >= it.list.len) return null;
const val = it.list.at(it.count);
it.count += 1;
return val;
}
pub fn reset(it: *Iterator) void {
it.count = 0;
}
};
pub fn iterator(self: *const Self) Iterator {
return Iterator{
.list = self,
.count = 0,
};
}
};
}
test "std.ArrayList.basic" {
var bytes: [1024]u8 = undefined;
const allocator = &std.heap.FixedBufferAllocator.init(bytes[0..]).allocator;
var list = ArrayList(i32).init(allocator);
defer list.deinit();
// setting on empty list is out of bounds
assertError(list.setOrError(0, 1), error.OutOfBounds);
{
var i: usize = 0;
while (i < 10) : (i += 1) {
list.append(@intCast(i32, i + 1)) catch unreachable;
}
}
{
var i: usize = 0;
while (i < 10) : (i += 1) {
assert(list.items[i] == @intCast(i32, i + 1));
}
}
for (list.toSlice()) |v, i| {
assert(v == @intCast(i32, i + 1));
}
for (list.toSliceConst()) |v, i| {
assert(v == @intCast(i32, i + 1));
}
assert(list.pop() == 10);
assert(list.len == 9);
list.appendSlice([]const i32{
1,
2,
3,
}) catch unreachable;
assert(list.len == 12);
assert(list.pop() == 3);
assert(list.pop() == 2);
assert(list.pop() == 1);
assert(list.len == 9);
list.appendSlice([]const i32{}) catch unreachable;
assert(list.len == 9);
// can only set on indices < self.len
list.set(7, 33);
list.set(8, 42);
assertError(list.setOrError(9, 99), error.OutOfBounds);
assertError(list.setOrError(10, 123), error.OutOfBounds);
assert(list.pop() == 42);
assert(list.pop() == 33);
}
test "std.ArrayList.swapRemove" {
var list = ArrayList(i32).init(debug.global_allocator);
defer list.deinit();
try list.append(1);
try list.append(2);
try list.append(3);
try list.append(4);
try list.append(5);
try list.append(6);
try list.append(7);
//remove from middle
assert(list.swapRemove(3) == 4);
assert(list.at(3) == 7);
assert(list.len == 6);
//remove from end
assert(list.swapRemove(5) == 6);
assert(list.len == 5);
//remove from front
assert(list.swapRemove(0) == 1);
assert(list.at(0) == 5);
assert(list.len == 4);
}
test "std.ArrayList.swapRemoveOrError" {
var list = ArrayList(i32).init(debug.global_allocator);
defer list.deinit();
// Test just after initialization
assertError(list.swapRemoveOrError(0), error.OutOfBounds);
// Test after adding one item and remote it
try list.append(1);
assert((try list.swapRemoveOrError(0)) == 1);
assertError(list.swapRemoveOrError(0), error.OutOfBounds);
// Test after adding two items and remote both
try list.append(1);
try list.append(2);
assert((try list.swapRemoveOrError(1)) == 2);
assert((try list.swapRemoveOrError(0)) == 1);
assertError(list.swapRemoveOrError(0), error.OutOfBounds);
// Test out of bounds with one item
try list.append(1);
assertError(list.swapRemoveOrError(1), error.OutOfBounds);
// Test out of bounds with two items
try list.append(2);
assertError(list.swapRemoveOrError(2), error.OutOfBounds);
}
test "std.ArrayList.iterator" {
var list = ArrayList(i32).init(debug.global_allocator);
defer list.deinit();
try list.append(1);
try list.append(2);
try list.append(3);
var count: i32 = 0;
var it = list.iterator();
while (it.next()) |next| {
assert(next == count + 1);
count += 1;
}
assert(count == 3);
assert(it.next() == null);
it.reset();
count = 0;
while (it.next()) |next| {
assert(next == count + 1);
count += 1;
if (count == 2) break;
}
it.reset();
assert(it.next().? == 1);
}
test "std.ArrayList.insert" {
var list = ArrayList(i32).init(debug.global_allocator);
defer list.deinit();
try list.append(1);
try list.append(2);
try list.append(3);
try list.insert(0, 5);
assert(list.items[0] == 5);
assert(list.items[1] == 1);
assert(list.items[2] == 2);
assert(list.items[3] == 3);
}
test "std.ArrayList.insertSlice" {
var list = ArrayList(i32).init(debug.global_allocator);
defer list.deinit();
try list.append(1);
try list.append(2);
try list.append(3);
try list.append(4);
try list.insertSlice(1, []const i32{
9,
8,
});
assert(list.items[0] == 1);
assert(list.items[1] == 9);
assert(list.items[2] == 8);
assert(list.items[3] == 2);
assert(list.items[4] == 3);
assert(list.items[5] == 4);
const items = []const i32{1};
try list.insertSlice(0, items[0..0]);
assert(list.len == 6);
assert(list.items[0] == 1);
}