225 lines
7.7 KiB
Zig
225 lines
7.7 KiB
Zig
const std = @import("std.zig");
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const debug = std.debug;
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const mem = std.mem;
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const Allocator = mem.Allocator;
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const assert = debug.assert;
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const testing = std.testing;
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const ArrayList = std.ArrayList;
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/// A contiguous, growable list of items in memory, with a sentinel after them.
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/// The sentinel is maintained when appending, resizing, etc.
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/// If you do not need a sentinel, consider using `ArrayList` instead.
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pub fn ArrayListSentineled(comptime T: type, comptime sentinel: T) type {
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return struct {
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list: ArrayList(T),
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const Self = @This();
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/// Must deinitialize with deinit.
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pub fn init(allocator: *Allocator, m: []const T) !Self {
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var self = try initSize(allocator, m.len);
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mem.copy(T, self.list.items, m);
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return self;
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}
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/// Initialize memory to size bytes of undefined values.
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/// Must deinitialize with deinit.
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pub fn initSize(allocator: *Allocator, size: usize) !Self {
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var self = initNull(allocator);
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try self.resize(size);
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return self;
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}
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/// Initialize with capacity to hold at least num bytes.
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/// Must deinitialize with deinit.
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pub fn initCapacity(allocator: *Allocator, num: usize) !Self {
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var self = Self{ .list = try ArrayList(T).initCapacity(allocator, num + 1) };
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self.list.appendAssumeCapacity(sentinel);
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return self;
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}
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/// Must deinitialize with deinit.
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/// None of the other operations are valid until you do one of these:
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/// * `replaceContents`
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/// * `resize`
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pub fn initNull(allocator: *Allocator) Self {
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return Self{ .list = ArrayList(T).init(allocator) };
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}
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/// Must deinitialize with deinit.
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pub fn initFromBuffer(buffer: Self) !Self {
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return Self.init(buffer.list.allocator, buffer.span());
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}
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/// Takes ownership of the passed in slice. The slice must have been
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/// allocated with `allocator`.
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/// Must deinitialize with deinit.
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pub fn fromOwnedSlice(allocator: *Allocator, slice: []T) !Self {
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var self = Self{ .list = ArrayList(T).fromOwnedSlice(allocator, slice) };
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try self.list.append(sentinel);
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return self;
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}
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/// The caller owns the returned memory. The list becomes null and is safe to `deinit`.
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pub fn toOwnedSlice(self: *Self) [:sentinel]T {
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const allocator = self.list.allocator;
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const result = self.list.toOwnedSlice();
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self.* = initNull(allocator);
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return result[0 .. result.len - 1 :sentinel];
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}
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/// Only works when `T` is `u8`.
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pub fn allocPrint(allocator: *Allocator, comptime format: []const u8, args: var) !Self {
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const size = std.math.cast(usize, std.fmt.count(format, args)) catch |err| switch (err) {
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error.Overflow => return error.OutOfMemory,
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};
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var self = try Self.initSize(allocator, size);
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assert((std.fmt.bufPrint(self.list.items, format, args) catch unreachable).len == size);
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return self;
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}
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pub fn deinit(self: *Self) void {
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self.list.deinit();
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}
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pub fn span(self: var) @TypeOf(self.list.items[0..:sentinel]) {
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return self.list.items[0..self.len() :sentinel];
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}
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pub fn shrink(self: *Self, new_len: usize) void {
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assert(new_len <= self.len());
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self.list.shrink(new_len + 1);
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self.list.items[self.len()] = sentinel;
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}
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pub fn resize(self: *Self, new_len: usize) !void {
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try self.list.resize(new_len + 1);
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self.list.items[self.len()] = sentinel;
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}
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pub fn isNull(self: Self) bool {
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return self.list.items.len == 0;
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}
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pub fn len(self: Self) usize {
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return self.list.items.len - 1;
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}
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pub fn capacity(self: Self) usize {
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return if (self.list.capacity > 0)
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self.list.capacity - 1
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else
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0;
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}
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pub fn appendSlice(self: *Self, m: []const T) !void {
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const old_len = self.len();
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try self.resize(old_len + m.len);
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mem.copy(T, self.list.items[old_len..], m);
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}
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pub fn append(self: *Self, byte: T) !void {
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const old_len = self.len();
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try self.resize(old_len + 1);
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self.list.items[old_len] = byte;
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}
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pub fn eql(self: Self, m: []const T) bool {
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return mem.eql(T, self.span(), m);
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}
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pub fn startsWith(self: Self, m: []const T) bool {
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if (self.len() < m.len) return false;
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return mem.eql(T, self.list.items[0..m.len], m);
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}
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pub fn endsWith(self: Self, m: []const T) bool {
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const l = self.len();
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if (l < m.len) return false;
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const start = l - m.len;
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return mem.eql(T, self.list.items[start..l], m);
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}
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pub fn replaceContents(self: *Self, m: []const T) !void {
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try self.resize(m.len);
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mem.copy(T, self.list.span(), m);
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}
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/// Initializes an OutStream which will append to the list.
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/// This function may be called only when `T` is `u8`.
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pub fn outStream(self: *Self) std.io.OutStream(*Self, error{OutOfMemory}, appendWrite) {
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return .{ .context = self };
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}
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/// Same as `append` except it returns the number of bytes written, which is always the same
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/// as `m.len`. The purpose of this function existing is to match `std.io.OutStream` API.
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/// This function may be called only when `T` is `u8`.
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pub fn appendWrite(self: *Self, m: []const u8) !usize {
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try self.appendSlice(m);
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return m.len;
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}
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};
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}
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test "simple" {
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var buf = try ArrayListSentineled(u8, 0).init(testing.allocator, "");
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defer buf.deinit();
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testing.expect(buf.len() == 0);
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try buf.appendSlice("hello");
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try buf.appendSlice(" ");
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try buf.appendSlice("world");
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testing.expect(buf.eql("hello world"));
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testing.expect(mem.eql(u8, mem.spanZ(buf.span().ptr), buf.span()));
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var buf2 = try ArrayListSentineled(u8, 0).initFromBuffer(buf);
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defer buf2.deinit();
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testing.expect(buf.eql(buf2.span()));
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testing.expect(buf.startsWith("hell"));
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testing.expect(buf.endsWith("orld"));
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try buf2.resize(4);
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testing.expect(buf.startsWith(buf2.span()));
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}
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test "initSize" {
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var buf = try ArrayListSentineled(u8, 0).initSize(testing.allocator, 3);
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defer buf.deinit();
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testing.expect(buf.len() == 3);
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try buf.appendSlice("hello");
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testing.expect(mem.eql(u8, buf.span()[3..], "hello"));
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}
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test "initCapacity" {
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var buf = try ArrayListSentineled(u8, 0).initCapacity(testing.allocator, 10);
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defer buf.deinit();
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testing.expect(buf.len() == 0);
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testing.expect(buf.capacity() >= 10);
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const old_cap = buf.capacity();
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try buf.appendSlice("hello");
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testing.expect(buf.len() == 5);
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testing.expect(buf.capacity() == old_cap);
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testing.expect(mem.eql(u8, buf.span(), "hello"));
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}
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test "print" {
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var buf = try ArrayListSentineled(u8, 0).init(testing.allocator, "");
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defer buf.deinit();
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try buf.outStream().print("Hello {} the {}", .{ 2, "world" });
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testing.expect(buf.eql("Hello 2 the world"));
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}
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test "outStream" {
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var buffer = try ArrayListSentineled(u8, 0).initSize(testing.allocator, 0);
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defer buffer.deinit();
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const buf_stream = buffer.outStream();
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const x: i32 = 42;
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const y: i32 = 1234;
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try buf_stream.print("x: {}\ny: {}\n", .{ x, y });
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testing.expect(mem.eql(u8, buffer.span(), "x: 42\ny: 1234\n"));
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}
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