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std.ArrayList.ensureTotalCapacity: optimize and fix integer overflow

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Fixes #12099
This commit is contained in:
alichraghi 2022-07-13 17:30:51 +04:30 committed by Andrew Kelley
parent 78cd7b57ef
commit 8c9f468fdd
1 changed files with 9 additions and 8 deletions
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17
lib/std/array_list.zig
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@ -3,6 +3,7 @@ const debug = std.debug;
const assert = debug.assert;
const testing = std.testing;
const mem = std.mem;
const math = std.math;
const Allocator = mem.Allocator;
/// A contiguous, growable list of items in memory.
@ -330,17 +331,17 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
/// Invalidates pointers if additional memory is needed.
pub fn ensureTotalCapacity(self: *Self, new_capacity: usize) Allocator.Error!void {
if (@sizeOf(T) > 0) {
var better_capacity = self.capacity;
if (better_capacity >= new_capacity) return;
if (self.capacity >= new_capacity) return;
var better_capacity = self.capacity;
while (true) {
better_capacity += better_capacity / 2 + 8;
better_capacity +|= better_capacity / 2 + 8;
if (better_capacity >= new_capacity) break;
}
return self.ensureTotalCapacityPrecise(better_capacity);
} else {
self.capacity = std.math.maxInt(usize);
self.capacity = math.maxInt(usize);
}
}
@ -357,7 +358,7 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
self.items.ptr = new_memory.ptr;
self.capacity = new_memory.len;
} else {
self.capacity = std.math.maxInt(usize);
self.capacity = math.maxInt(usize);
}
}
@ -725,11 +726,11 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) typ
/// Modify the array so that it can hold at least `new_capacity` items.
/// Invalidates pointers if additional memory is needed.
pub fn ensureTotalCapacity(self: *Self, allocator: Allocator, new_capacity: usize) Allocator.Error!void {
var better_capacity = self.capacity;
if (better_capacity >= new_capacity) return;
if (self.capacity >= new_capacity) return;
var better_capacity = self.capacity;
while (true) {
better_capacity += better_capacity / 2 + 8;
better_capacity +|= better_capacity / 2 + 8;
if (better_capacity >= new_capacity) break;
}