aboutsummaryrefslogtreecommitdiff
path: root/lib/std/bounded_array.zig
diff options
context:
space:
mode:
authorAndrew Kelley <andrew@ziglang.org>2025-08-04 23:51:45 -0700
committerAndrew Kelley <andrew@ziglang.org>2025-08-05 09:56:02 -0700
commit196e36bbb27b0f0ebd7cd7a866b85f477b3662fb (patch)
tree04efce99fc296278385acbd0a27acdb52d916358 /lib/std/bounded_array.zig
parentc47ec4f3d7a6bf79be3adcffa33aa51bcc26ed0b (diff)
downloadzig-196e36bbb27b0f0ebd7cd7a866b85f477b3662fb.tar.gz
zig-196e36bbb27b0f0ebd7cd7a866b85f477b3662fb.zip
std: remove BoundedArray
This use case is handled by ArrayListUnmanaged via the "...Bounded" method variants, and it's more optimal to share machine code, versus generating multiple versions of each function for differing array lengths.
Diffstat (limited to 'lib/std/bounded_array.zig')
-rw-r--r--lib/std/bounded_array.zig412
1 files changed, 0 insertions, 412 deletions
diff --git a/lib/std/bounded_array.zig b/lib/std/bounded_array.zig
deleted file mode 100644
index 7864dfb775..0000000000
--- a/lib/std/bounded_array.zig
+++ /dev/null
@@ -1,412 +0,0 @@
-const std = @import("std.zig");
-const assert = std.debug.assert;
-const mem = std.mem;
-const testing = std.testing;
-const Alignment = std.mem.Alignment;
-
-/// A structure with an array and a length, that can be used as a slice.
-///
-/// Useful to pass around small arrays whose exact size is only known at
-/// runtime, but whose maximum size is known at comptime, without requiring
-/// an `Allocator`.
-///
-/// ```zig
-/// var actual_size = 32;
-/// var a = try BoundedArray(u8, 64).init(actual_size);
-/// var slice = a.slice(); // a slice of the 64-byte array
-/// var a_clone = a; // creates a copy - the structure doesn't use any internal pointers
-/// ```
-pub fn BoundedArray(comptime T: type, comptime buffer_capacity: usize) type {
- return BoundedArrayAligned(T, .of(T), buffer_capacity);
-}
-
-/// A structure with an array, length and alignment, that can be used as a
-/// slice.
-///
-/// Useful to pass around small explicitly-aligned arrays whose exact size is
-/// only known at runtime, but whose maximum size is known at comptime, without
-/// requiring an `Allocator`.
-/// ```zig
-// var a = try BoundedArrayAligned(u8, 16, 2).init(0);
-// try a.append(255);
-// try a.append(255);
-// const b = @ptrCast(*const [1]u16, a.constSlice().ptr);
-// try testing.expectEqual(@as(u16, 65535), b[0]);
-/// ```
-pub fn BoundedArrayAligned(
- comptime T: type,
- comptime alignment: Alignment,
- comptime buffer_capacity: usize,
-) type {
- return struct {
- const Self = @This();
- buffer: [buffer_capacity]T align(alignment.toByteUnits()) = undefined,
- len: usize = 0,
-
- /// Set the actual length of the slice.
- /// Returns error.Overflow if it exceeds the length of the backing array.
- pub fn init(len: usize) error{Overflow}!Self {
- if (len > buffer_capacity) return error.Overflow;
- return Self{ .len = len };
- }
-
- /// View the internal array as a slice whose size was previously set.
- pub fn slice(self: anytype) switch (@TypeOf(&self.buffer)) {
- *align(alignment.toByteUnits()) [buffer_capacity]T => []align(alignment.toByteUnits()) T,
- *align(alignment.toByteUnits()) const [buffer_capacity]T => []align(alignment.toByteUnits()) const T,
- else => unreachable,
- } {
- return self.buffer[0..self.len];
- }
-
- /// View the internal array as a constant slice whose size was previously set.
- pub fn constSlice(self: *const Self) []align(alignment.toByteUnits()) const T {
- return self.slice();
- }
-
- /// Adjust the slice's length to `len`.
- /// Does not initialize added items if any.
- pub fn resize(self: *Self, len: usize) error{Overflow}!void {
- if (len > buffer_capacity) return error.Overflow;
- self.len = len;
- }
-
- /// Remove all elements from the slice.
- pub fn clear(self: *Self) void {
- self.len = 0;
- }
-
- /// Copy the content of an existing slice.
- pub fn fromSlice(m: []const T) error{Overflow}!Self {
- var list = try init(m.len);
- @memcpy(list.slice(), m);
- return list;
- }
-
- /// Return the element at index `i` of the slice.
- pub fn get(self: Self, i: usize) T {
- return self.constSlice()[i];
- }
-
- /// Set the value of the element at index `i` of the slice.
- pub fn set(self: *Self, i: usize, item: T) void {
- self.slice()[i] = item;
- }
-
- /// Return the maximum length of a slice.
- pub fn capacity(self: Self) usize {
- return self.buffer.len;
- }
-
- /// Check that the slice can hold at least `additional_count` items.
- pub fn ensureUnusedCapacity(self: Self, additional_count: usize) error{Overflow}!void {
- if (self.len + additional_count > buffer_capacity) {
- return error.Overflow;
- }
- }
-
- /// Increase length by 1, returning a pointer to the new item.
- pub fn addOne(self: *Self) error{Overflow}!*T {
- try self.ensureUnusedCapacity(1);
- return self.addOneAssumeCapacity();
- }
-
- /// Increase length by 1, returning pointer to the new item.
- /// Asserts that there is space for the new item.
- pub fn addOneAssumeCapacity(self: *Self) *T {
- assert(self.len < buffer_capacity);
- self.len += 1;
- return &self.slice()[self.len - 1];
- }
-
- /// Resize the slice, adding `n` new elements, which have `undefined` values.
- /// The return value is a pointer to the array of uninitialized elements.
- pub fn addManyAsArray(self: *Self, comptime n: usize) error{Overflow}!*align(alignment.toByteUnits()) [n]T {
- const prev_len = self.len;
- try self.resize(self.len + n);
- return self.slice()[prev_len..][0..n];
- }
-
- /// Resize the slice, adding `n` new elements, which have `undefined` values.
- /// The return value is a slice pointing to the uninitialized elements.
- pub fn addManyAsSlice(self: *Self, n: usize) error{Overflow}![]align(alignment.toByteUnits()) T {
- const prev_len = self.len;
- try self.resize(self.len + n);
- return self.slice()[prev_len..][0..n];
- }
-
- /// Remove and return the last element from the slice, or return `null` if the slice is empty.
- pub fn pop(self: *Self) ?T {
- if (self.len == 0) return null;
- const item = self.get(self.len - 1);
- self.len -= 1;
- return item;
- }
-
- /// Return a slice of only the extra capacity after items.
- /// This can be useful for writing directly into it.
- /// Note that such an operation must be followed up with a
- /// call to `resize()`
- pub fn unusedCapacitySlice(self: *Self) []align(alignment.toByteUnits()) T {
- return self.buffer[self.len..];
- }
-
- /// Insert `item` at index `i` by moving `slice[n .. slice.len]` to make room.
- /// This operation is O(N).
- pub fn insert(
- self: *Self,
- i: usize,
- item: T,
- ) error{Overflow}!void {
- if (i > self.len) {
- return error.Overflow;
- }
- _ = try self.addOne();
- var s = self.slice();
- mem.copyBackwards(T, s[i + 1 .. s.len], s[i .. s.len - 1]);
- self.buffer[i] = item;
- }
-
- /// Insert slice `items` at index `i` by moving `slice[i .. slice.len]` to make room.
- /// This operation is O(N).
- pub fn insertSlice(self: *Self, i: usize, items: []const T) error{Overflow}!void {
- try self.ensureUnusedCapacity(items.len);
- self.len += items.len;
- mem.copyBackwards(T, self.slice()[i + items.len .. self.len], self.constSlice()[i .. self.len - items.len]);
- @memcpy(self.slice()[i..][0..items.len], items);
- }
-
- /// Replace range of elements `slice[start..][0..len]` with `new_items`.
- /// Grows slice if `len < new_items.len`.
- /// Shrinks slice if `len > new_items.len`.
- pub fn replaceRange(
- self: *Self,
- start: usize,
- len: usize,
- new_items: []const T,
- ) error{Overflow}!void {
- const after_range = start + len;
- var range = self.slice()[start..after_range];
-
- if (range.len == new_items.len) {
- @memcpy(range[0..new_items.len], new_items);
- } else if (range.len < new_items.len) {
- const first = new_items[0..range.len];
- const rest = new_items[range.len..];
- @memcpy(range[0..first.len], first);
- try self.insertSlice(after_range, rest);
- } else {
- @memcpy(range[0..new_items.len], new_items);
- const after_subrange = start + new_items.len;
- for (self.constSlice()[after_range..], 0..) |item, i| {
- self.slice()[after_subrange..][i] = item;
- }
- self.len -= len - new_items.len;
- }
- }
-
- /// Extend the slice by 1 element.
- pub fn append(self: *Self, item: T) error{Overflow}!void {
- const new_item_ptr = try self.addOne();
- new_item_ptr.* = item;
- }
-
- /// Extend the slice by 1 element, asserting the capacity is already
- /// enough to store the new item.
- pub fn appendAssumeCapacity(self: *Self, item: T) void {
- const new_item_ptr = self.addOneAssumeCapacity();
- new_item_ptr.* = item;
- }
-
- /// Remove the element at index `i`, shift elements after index
- /// `i` forward, and return the removed element.
- /// Asserts the slice has at least one item.
- /// This operation is O(N).
- pub fn orderedRemove(self: *Self, i: usize) T {
- const newlen = self.len - 1;
- if (newlen == i) return self.pop().?;
- const old_item = self.get(i);
- for (self.slice()[i..newlen], 0..) |*b, j| b.* = self.get(i + 1 + j);
- self.set(newlen, undefined);
- self.len = newlen;
- return old_item;
- }
-
- /// Remove the element at the specified index and return it.
- /// The empty slot is filled from the end of the slice.
- /// This operation is O(1).
- pub fn swapRemove(self: *Self, i: usize) T {
- if (self.len - 1 == i) return self.pop().?;
- const old_item = self.get(i);
- self.set(i, self.pop().?);
- return old_item;
- }
-
- /// Append the slice of items to the slice.
- pub fn appendSlice(self: *Self, items: []const T) error{Overflow}!void {
- try self.ensureUnusedCapacity(items.len);
- self.appendSliceAssumeCapacity(items);
- }
-
- /// Append the slice of items to the slice, asserting the capacity is already
- /// enough to store the new items.
- pub fn appendSliceAssumeCapacity(self: *Self, items: []const T) void {
- const old_len = self.len;
- self.len += items.len;
- @memcpy(self.slice()[old_len..][0..items.len], items);
- }
-
- /// Append a value to the slice `n` times.
- /// Allocates more memory as necessary.
- pub fn appendNTimes(self: *Self, value: T, n: usize) error{Overflow}!void {
- const old_len = self.len;
- try self.resize(old_len + n);
- @memset(self.slice()[old_len..self.len], value);
- }
-
- /// Append a value to the slice `n` times.
- /// Asserts the capacity is enough.
- pub fn appendNTimesAssumeCapacity(self: *Self, value: T, n: usize) void {
- const old_len = self.len;
- self.len += n;
- assert(self.len <= buffer_capacity);
- @memset(self.slice()[old_len..self.len], value);
- }
-
- pub const Writer = if (T != u8)
- @compileError("The Writer interface is only defined for BoundedArray(u8, ...) " ++
- "but the given type is BoundedArray(" ++ @typeName(T) ++ ", ...)")
- else
- std.io.GenericWriter(*Self, error{Overflow}, appendWrite);
-
- /// Initializes a writer which will write into the array.
- pub fn writer(self: *Self) Writer {
- return .{ .context = self };
- }
-
- /// Same as `appendSlice` except it returns the number of bytes written, which is always the same
- /// as `m.len`. The purpose of this function existing is to match `std.io.GenericWriter` API.
- fn appendWrite(self: *Self, m: []const u8) error{Overflow}!usize {
- try self.appendSlice(m);
- return m.len;
- }
- };
-}
-
-test BoundedArray {
- var a = try BoundedArray(u8, 64).init(32);
-
- try testing.expectEqual(a.capacity(), 64);
- try testing.expectEqual(a.slice().len, 32);
- try testing.expectEqual(a.constSlice().len, 32);
-
- try a.resize(48);
- try testing.expectEqual(a.len, 48);
-
- const x = [_]u8{1} ** 10;
- a = try BoundedArray(u8, 64).fromSlice(&x);
- try testing.expectEqualSlices(u8, &x, a.constSlice());
-
- var a2 = a;
- try testing.expectEqualSlices(u8, a.constSlice(), a2.constSlice());
- a2.set(0, 0);
- try testing.expect(a.get(0) != a2.get(0));
-
- try testing.expectError(error.Overflow, a.resize(100));
- try testing.expectError(error.Overflow, BoundedArray(u8, x.len - 1).fromSlice(&x));
-
- try a.resize(0);
- try a.ensureUnusedCapacity(a.capacity());
- (try a.addOne()).* = 0;
- try a.ensureUnusedCapacity(a.capacity() - 1);
- try testing.expectEqual(a.len, 1);
-
- const uninitialized = try a.addManyAsArray(4);
- try testing.expectEqual(uninitialized.len, 4);
- try testing.expectEqual(a.len, 5);
-
- try a.append(0xff);
- try testing.expectEqual(a.len, 6);
- try testing.expectEqual(a.pop(), 0xff);
-
- a.appendAssumeCapacity(0xff);
- try testing.expectEqual(a.len, 6);
- try testing.expectEqual(a.pop(), 0xff);
-
- try a.resize(1);
- try testing.expectEqual(a.pop(), 0);
- try testing.expectEqual(a.pop(), null);
- var unused = a.unusedCapacitySlice();
- @memset(unused[0..8], 2);
- unused[8] = 3;
- unused[9] = 4;
- try testing.expectEqual(unused.len, a.capacity());
- try a.resize(10);
-
- try a.insert(5, 0xaa);
- try testing.expectEqual(a.len, 11);
- try testing.expectEqual(a.get(5), 0xaa);
- try testing.expectEqual(a.get(9), 3);
- try testing.expectEqual(a.get(10), 4);
-
- try a.insert(11, 0xbb);
- try testing.expectEqual(a.len, 12);
- try testing.expectEqual(a.pop(), 0xbb);
-
- try a.appendSlice(&x);
- try testing.expectEqual(a.len, 11 + x.len);
-
- try a.appendNTimes(0xbb, 5);
- try testing.expectEqual(a.len, 11 + x.len + 5);
- try testing.expectEqual(a.pop(), 0xbb);
-
- a.appendNTimesAssumeCapacity(0xcc, 5);
- try testing.expectEqual(a.len, 11 + x.len + 5 - 1 + 5);
- try testing.expectEqual(a.pop(), 0xcc);
-
- try testing.expectEqual(a.len, 29);
- try a.replaceRange(1, 20, &x);
- try testing.expectEqual(a.len, 29 + x.len - 20);
-
- try a.insertSlice(0, &x);
- try testing.expectEqual(a.len, 29 + x.len - 20 + x.len);
-
- try a.replaceRange(1, 5, &x);
- try testing.expectEqual(a.len, 29 + x.len - 20 + x.len + x.len - 5);
-
- try a.append(10);
- try testing.expectEqual(a.pop(), 10);
-
- try a.append(20);
- const removed = a.orderedRemove(5);
- try testing.expectEqual(removed, 1);
- try testing.expectEqual(a.len, 34);
-
- a.set(0, 0xdd);
- a.set(a.len - 1, 0xee);
- const swapped = a.swapRemove(0);
- try testing.expectEqual(swapped, 0xdd);
- try testing.expectEqual(a.get(0), 0xee);
-
- const added_slice = try a.addManyAsSlice(3);
- try testing.expectEqual(added_slice.len, 3);
- try testing.expectEqual(a.len, 36);
-
- while (a.pop()) |_| {}
- const w = a.writer();
- const s = "hello, this is a test string";
- try w.writeAll(s);
- try testing.expectEqualStrings(s, a.constSlice());
-}
-
-test "BoundedArrayAligned" {
- var a = try BoundedArrayAligned(u8, .@"16", 4).init(0);
- try a.append(0);
- try a.append(0);
- try a.append(255);
- try a.append(255);
-
- const b = @as(*const [2]u16, @ptrCast(a.constSlice().ptr));
- try testing.expectEqual(@as(u16, 0), b[0]);
- try testing.expectEqual(@as(u16, 65535), b[1]);
-}