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std.big.int.Mutable: fix set(@as(DoubleLimb, 0))

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Previously, this would set len to 1 but fail to initialize any limbs.
This commit is contained in:
Jacob Young 2022-11-28 04:37:47 -05:00 committed by Andrew Kelley
parent e5d76176b9
commit 2f11de4f51
2 changed files with 14 additions and 2 deletions
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8
lib/std/math/big/int.zig
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@ -238,12 +238,14 @@ pub const Mutable = struct {
self.limbs[0] = w_value;
} else {
var i: usize = 0;
while (w_value != 0) : (i += 1) {
while (true) : (i += 1) {
self.limbs[i] = @truncate(Limb, w_value);
// TODO: shift == 64 at compile-time fails. Fails on u128 limbs.
w_value >>= limb_bits / 2;
w_value >>= limb_bits / 2;
if (w_value == 0) break;
}
}
},
@ -256,11 +258,13 @@ pub const Mutable = struct {
const mask = (1 << limb_bits) - 1;
comptime var i = 0;
inline while (w_value != 0) : (i += 1) {
inline while (true) : (i += 1) {
self.limbs[i] = w_value & mask;
w_value >>= limb_bits / 2;
w_value >>= limb_bits / 2;
if (w_value == 0) break;
}
}
},

8
lib/std/math/big/int_test.zig
View File

@ -69,6 +69,14 @@ test "big.int set negative minimum" {
try testing.expect((try a.to(i64)) == minInt(i64));
}
test "big.int set double-width maximum then zero" {
var a = try Managed.initSet(testing.allocator, maxInt(DoubleLimb));
defer a.deinit();
try a.set(@as(DoubleLimb, 0));
try testing.expectEqual(@as(DoubleLimb, 0), try a.to(DoubleLimb));
}
test "big.int to target too small error" {
var a = try Managed.initSet(testing.allocator, 0xffffffff);
defer a.deinit();