authorgravatar for hnakamur@gmail.comHiroaki Nakamura <hnakamur@gmail.com> 2022-07-16 00:08:55+09:00
committergravatar for hnakamur@gmail.comHiroaki Nakamura <hnakamur@gmail.com> 2022-07-16 00:08:55+09:00
logd63604b11681ab196fb65e856bb6b12ebe8930af
tree7754de11927bf58f2dd758ff2437e1421812be2d
parent577f9fdbae12eabbbf87bd2cc36a1565df3153b2

Fix std.math.big.int.Managed capacity after mul and sqr

2 files changed, 34 insertions(+), 2 deletions(-)

lib/std/math/big/int.zig+2-2
......@@ -2780,7 +2780,7 @@ pub const Managed = struct {
27802780 if (alias_count == 0) {
27812781 m.mulNoAlias(a.toConst(), b.toConst(), rma.allocator);
27822782 } else {
2783 const limb_count = calcMulLimbsBufferLen(a.limbs.len, b.limbs.len, alias_count);
2783 const limb_count = calcMulLimbsBufferLen(a.toConst().limbs.len, b.toConst().limbs.len, alias_count);
27842784 const limbs_buffer = try rma.allocator.alloc(Limb, limb_count);
27852785 defer rma.allocator.free(limbs_buffer);
27862786 m.mul(a.toConst(), b.toConst(), limbs_buffer, rma.allocator);
......@@ -2960,7 +2960,7 @@ pub const Managed = struct {
29602960
29612961 /// r = a * a
29622962 pub fn sqr(rma: *Managed, a: *const Managed) !void {
2963 const needed_limbs = 2 * a.limbs.len + 1;
2963 const needed_limbs = 2 * a.toConst().limbs.len + 1;
29642964
29652965 if (rma.limbs.ptr == a.limbs.ptr) {
29662966 var m = try Managed.initCapacity(rma.allocator, needed_limbs);
lib/std/math/big/int_test.zig+32
......@@ -2883,3 +2883,35 @@ test "big int byte swap" {
28832883 try byteSwapTest(i32, 0x123456f8, @bitCast(i32, @as(u32, 0xf8563412)));
28842884 try byteSwapTest(i48, 0x123456789abc, @bitCast(i48, @as(u48, 0xbc9a78563412)));
28852885}
2886
2887test "big.int mul multi-multi alias r with a and b" {
2888 var a = try Managed.initSet(testing.allocator, 2 * maxInt(Limb));
2889 defer a.deinit();
2890
2891 try a.mul(&a, &a);
2892
2893 var want = try Managed.initSet(testing.allocator, 4 * maxInt(Limb) * maxInt(Limb));
2894 defer want.deinit();
2895
2896 try testing.expect(a.eq(want));
2897
2898 if (@typeInfo(Limb).Int.bits == 64) {
2899 try testing.expectEqual(@as(usize, 5), a.limbs.len);
2900 }
2901}
2902
2903test "big.int sqr multi alias r with a" {
2904 var a = try Managed.initSet(testing.allocator, 2 * maxInt(Limb));
2905 defer a.deinit();
2906
2907 try a.sqr(&a);
2908
2909 var want = try Managed.initSet(testing.allocator, 4 * maxInt(Limb) * maxInt(Limb));
2910 defer want.deinit();
2911
2912 try testing.expect(a.eq(want));
2913
2914 if (@typeInfo(Limb).Int.bits == 64) {
2915 try testing.expectEqual(@as(usize, 5), a.limbs.len);
2916 }
2917}