138 lines
4.1 KiB
Zig
138 lines
4.1 KiB
Zig
const debug = @import("debug.zig");
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const assert = debug.assert;
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const mem = @import("mem.zig");
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const Allocator = mem.Allocator;
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pub fn ArrayList(comptime T: type) -> type {
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return AlignedArrayList(T, @alignOf(T));
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}
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pub fn AlignedArrayList(comptime T: type, comptime A: u29) -> type{
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struct {
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const Self = this;
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/// Use toSlice instead of slicing this directly, because if you don't
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/// specify the end position of the slice, this will potentially give
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/// you uninitialized memory.
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items: []align(A) T,
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len: usize,
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allocator: &Allocator,
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/// Deinitialize with `deinit` or use `toOwnedSlice`.
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pub fn init(allocator: &Allocator) -> Self {
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Self {
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.items = []align(A) T{},
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.len = 0,
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.allocator = allocator,
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}
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}
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pub fn deinit(l: &Self) {
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l.allocator.free(l.items);
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}
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pub fn toSlice(l: &Self) -> []align(A) T {
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return l.items[0..l.len];
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}
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pub fn toSliceConst(l: &const Self) -> []align(A) const T {
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return l.items[0..l.len];
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}
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/// ArrayList takes ownership of the passed in slice. The slice must have been
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/// allocated with `allocator`.
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/// Deinitialize with `deinit` or use `toOwnedSlice`.
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pub fn fromOwnedSlice(allocator: &Allocator, slice: []align(A) T) -> Self {
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return Self {
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.items = slice,
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.len = slice.len,
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.allocator = allocator,
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};
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}
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/// The caller owns the returned memory. ArrayList becomes empty.
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pub fn toOwnedSlice(self: &Self) -> []align(A) T {
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const allocator = self.allocator;
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const result = allocator.alignedShrink(T, A, self.items, self.len);
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*self = init(allocator);
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return result;
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}
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pub fn append(l: &Self, item: &const T) -> %void {
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const new_item_ptr = %return l.addOne();
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*new_item_ptr = *item;
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}
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pub fn appendSlice(l: &Self, items: []align(A) const T) -> %void {
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%return l.ensureCapacity(l.len + items.len);
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mem.copy(T, l.items[l.len..], items);
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l.len += items.len;
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}
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pub fn resize(l: &Self, new_len: usize) -> %void {
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%return l.ensureCapacity(new_len);
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l.len = new_len;
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}
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pub fn shrink(l: &Self, new_len: usize) {
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assert(new_len <= l.len);
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l.len = new_len;
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}
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pub fn ensureCapacity(l: &Self, new_capacity: usize) -> %void {
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var better_capacity = l.items.len;
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if (better_capacity >= new_capacity) return;
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while (true) {
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better_capacity += better_capacity / 2 + 8;
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if (better_capacity >= new_capacity) break;
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}
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l.items = %return l.allocator.alignedRealloc(T, A, l.items, better_capacity);
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}
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pub fn addOne(l: &Self) -> %&T {
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const new_length = l.len + 1;
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%return l.ensureCapacity(new_length);
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const result = &l.items[l.len];
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l.len = new_length;
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return result;
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}
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pub fn pop(self: &Self) -> T {
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self.len -= 1;
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return self.items[self.len];
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}
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pub fn popOrNull(self: &Self) -> ?T {
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if (self.len == 0)
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return null;
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return self.pop();
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}
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}
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}
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test "basic ArrayList test" {
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var list = ArrayList(i32).init(debug.global_allocator);
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defer list.deinit();
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{var i: usize = 0; while (i < 10) : (i += 1) {
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%%list.append(i32(i + 1));
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}}
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{var i: usize = 0; while (i < 10) : (i += 1) {
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assert(list.items[i] == i32(i + 1));
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}}
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assert(list.pop() == 10);
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assert(list.len == 9);
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%%list.appendSlice([]const i32 { 1, 2, 3 });
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assert(list.len == 12);
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assert(list.pop() == 3);
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assert(list.pop() == 2);
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assert(list.pop() == 1);
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assert(list.len == 9);
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%%list.appendSlice([]const i32 {});
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assert(list.len == 9);
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}
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