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Merge pull request #18611 from erikarvstedt/array-list-overflow

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ArrayList: remove unneeded overflow checks
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Andrew Kelley 2024-01-19 12:10:00 -08:00 committed by GitHub
commit 3c16e80372
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1 changed files with 33 additions and 35 deletions
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68
lib/std/array_list.zig
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@ -126,7 +126,8 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
/// The caller owns the returned memory. Empties this ArrayList.
pub fn toOwnedSliceSentinel(self: *Self, comptime sentinel: T) Allocator.Error!SentinelSlice(sentinel) {
try self.ensureTotalCapacityPrecise(try addOrOom(self.items.len, 1));
// This addition can never overflow because `self.items` can never occupy the whole address space
try self.ensureTotalCapacityPrecise(self.items.len + 1);
self.appendAssumeCapacity(sentinel);
const result = try self.toOwnedSlice();
return result[0 .. result.len - 1 :sentinel];
@ -241,9 +242,9 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
/// Grows list if `len < new_items.len`.
/// Shrinks list if `len > new_items.len`.
/// Invalidates element pointers if this ArrayList is resized.
/// Asserts that the start index is in bounds or equal to the length.
/// Asserts that the range is in bounds.
pub fn replaceRange(self: *Self, start: usize, len: usize, new_items: []const T) Allocator.Error!void {
const after_range = try addOrOom(start, len);
const after_range = start + len;
const range = self.items[start..after_range];
if (range.len == new_items.len)
@ -256,7 +257,7 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
try self.insertSlice(after_range, rest);
} else {
@memcpy(range[0..new_items.len], new_items);
const after_subrange = try addOrOom(start, new_items.len);
const after_subrange = start + new_items.len;
for (self.items[after_range..], 0..) |item, i| {
self.items[after_subrange..][i] = item;
@ -493,7 +494,9 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
/// Increase length by 1, returning pointer to the new item.
/// The returned pointer becomes invalid when the list resized.
pub fn addOne(self: *Self) Allocator.Error!*T {
try self.ensureUnusedCapacity(1);
// This can never overflow because `self.items` can never occupy the whole address space
const newlen = self.items.len + 1;
try self.ensureTotalCapacity(newlen);
return self.addOneAssumeCapacity();
}
@ -710,7 +713,8 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) typ
/// The caller owns the returned memory. ArrayList becomes empty.
pub fn toOwnedSliceSentinel(self: *Self, allocator: Allocator, comptime sentinel: T) Allocator.Error!SentinelSlice(sentinel) {
try self.ensureTotalCapacityPrecise(allocator, try addOrOom(self.items.len, 1));
// This addition can never overflow because `self.items` can never occupy the whole address space
try self.ensureTotalCapacityPrecise(allocator, self.items.len + 1);
self.appendAssumeCapacity(sentinel);
const result = try self.toOwnedSlice(allocator);
return result[0 .. result.len - 1 :sentinel];
@ -1071,7 +1075,8 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) typ
/// Increase length by 1, returning pointer to the new item.
/// The returned element pointer becomes invalid when the list is resized.
pub fn addOne(self: *Self, allocator: Allocator) Allocator.Error!*T {
const newlen = try addOrOom(self.items.len, 1);
// This can never overflow because `self.items` can never occupy the whole address space
const newlen = self.items.len + 1;
try self.ensureTotalCapacity(allocator, newlen);
return self.addOneAssumeCapacity();
}
@ -1991,47 +1996,40 @@ test "std.ArrayList(u32).getLastOrNull()" {
test "return OutOfMemory when capacity would exceed maximum usize integer value" {
const a = testing.allocator;
const new_item: u32 = 42;
const items = &.{ 42, 43 };
{
var list: ArrayListUnmanaged(u32) = .{
.items = undefined,
.capacity = math.maxInt(usize),
.capacity = math.maxInt(usize) - 1,
};
list.items.len = math.maxInt(usize);
list.items.len = math.maxInt(usize) - 1;
try testing.expectError(error.OutOfMemory, list.append(a, new_item));
try testing.expectError(error.OutOfMemory, list.appendSlice(a, &.{new_item}));
try testing.expectError(error.OutOfMemory, list.appendNTimes(a, new_item, 1));
try testing.expectError(error.OutOfMemory, list.appendUnalignedSlice(a, &.{new_item}));
try testing.expectError(error.OutOfMemory, list.addOne(a));
try testing.expectError(error.OutOfMemory, list.addManyAt(a, 0, 1));
try testing.expectError(error.OutOfMemory, list.addManyAsArray(a, 1));
try testing.expectError(error.OutOfMemory, list.addManyAsSlice(a, 1));
try testing.expectError(error.OutOfMemory, list.insert(a, 0, new_item));
try testing.expectError(error.OutOfMemory, list.insertSlice(a, 0, &.{new_item}));
try testing.expectError(error.OutOfMemory, list.toOwnedSliceSentinel(a, 0));
try testing.expectError(error.OutOfMemory, list.ensureUnusedCapacity(a, 1));
try testing.expectError(error.OutOfMemory, list.appendSlice(a, items));
try testing.expectError(error.OutOfMemory, list.appendNTimes(a, new_item, 2));
try testing.expectError(error.OutOfMemory, list.appendUnalignedSlice(a, &.{ new_item, new_item }));
try testing.expectError(error.OutOfMemory, list.addManyAt(a, 0, 2));
try testing.expectError(error.OutOfMemory, list.addManyAsArray(a, 2));
try testing.expectError(error.OutOfMemory, list.addManyAsSlice(a, 2));
try testing.expectError(error.OutOfMemory, list.insertSlice(a, 0, items));
try testing.expectError(error.OutOfMemory, list.ensureUnusedCapacity(a, 2));
}
{
var list: ArrayList(u32) = .{
.items = undefined,
.capacity = math.maxInt(usize),
.capacity = math.maxInt(usize) - 1,
.allocator = a,
};
list.items.len = math.maxInt(usize);
list.items.len = math.maxInt(usize) - 1;
try testing.expectError(error.OutOfMemory, list.append(new_item));
try testing.expectError(error.OutOfMemory, list.appendSlice(&.{new_item}));
try testing.expectError(error.OutOfMemory, list.appendNTimes(new_item, 1));
try testing.expectError(error.OutOfMemory, list.appendUnalignedSlice(&.{new_item}));
try testing.expectError(error.OutOfMemory, list.addOne());
try testing.expectError(error.OutOfMemory, list.addManyAt(0, 1));
try testing.expectError(error.OutOfMemory, list.addManyAsArray(1));
try testing.expectError(error.OutOfMemory, list.addManyAsSlice(1));
try testing.expectError(error.OutOfMemory, list.insert(0, new_item));
try testing.expectError(error.OutOfMemory, list.insertSlice(0, &.{new_item}));
try testing.expectError(error.OutOfMemory, list.toOwnedSliceSentinel(0));
try testing.expectError(error.OutOfMemory, list.ensureUnusedCapacity(1));
try testing.expectError(error.OutOfMemory, list.appendSlice(items));
try testing.expectError(error.OutOfMemory, list.appendNTimes(new_item, 2));
try testing.expectError(error.OutOfMemory, list.appendUnalignedSlice(&.{ new_item, new_item }));
try testing.expectError(error.OutOfMemory, list.addManyAt(0, 2));
try testing.expectError(error.OutOfMemory, list.addManyAsArray(2));
try testing.expectError(error.OutOfMemory, list.addManyAsSlice(2));
try testing.expectError(error.OutOfMemory, list.insertSlice(0, items));
try testing.expectError(error.OutOfMemory, list.ensureUnusedCapacity(2));
}
}