authorgravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2022-07-19 18:54:30-04:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2022-07-19 18:54:30-04:00
log046df9b7d001120a0142ea29c86cfb3b9ae4eadf
tree219a4b90de182927ea2d687c2066015dce37d66d
parent6fab6c3e4696d11c2040ed2ea381ada01e74c6b9
parent3e667fd2925274c674bddfd2d3f67f6edd1bf72b
signaturebadge-question-mark Signed by PGP key 4AEE18F83AFDEB23

Merge pull request #12131 from hnakamur/fix_big_int_Managed_mul_sqr_capacity_too_large

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

2 files changed, 42 insertions(+), 10 deletions(-)

lib/std/math/big/int.zig+10-10
......@@ -2719,7 +2719,7 @@ pub const Managed = struct {
27192719 ///
27202720 /// Returns an error if memory could not be allocated.
27212721 pub fn sub(r: *Managed, a: *const Managed, b: *const Managed) !void {
2722 try r.ensureCapacity(math.max(a.limbs.len, b.limbs.len) + 1);
2722 try r.ensureCapacity(math.max(a.len(), b.len()) + 1);
27232723 var m = r.toMutable();
27242724 m.sub(a.toConst(), b.toConst());
27252725 r.setMetadata(m.positive, m.len);
......@@ -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.len(), b.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);
......@@ -2813,7 +2813,7 @@ pub const Managed = struct {
28132813 if (alias_count == 0) {
28142814 m.mulWrapNoAlias(a.toConst(), b.toConst(), signedness, bit_count, rma.allocator);
28152815 } else {
2816 const limb_count = calcMulWrapLimbsBufferLen(bit_count, a.limbs.len, b.limbs.len, alias_count);
2816 const limb_count = calcMulWrapLimbsBufferLen(bit_count, a.len(), b.len(), alias_count);
28172817 const limbs_buffer = try rma.allocator.alloc(Limb, limb_count);
28182818 defer rma.allocator.free(limbs_buffer);
28192819 m.mulWrap(a.toConst(), b.toConst(), signedness, bit_count, limbs_buffer, rma.allocator);
......@@ -2843,11 +2843,11 @@ pub const Managed = struct {
28432843 ///
28442844 /// Returns an error if memory could not be allocated.
28452845 pub fn divFloor(q: *Managed, r: *Managed, a: *const Managed, b: *const Managed) !void {
2846 try q.ensureCapacity(a.limbs.len);
2847 try r.ensureCapacity(b.limbs.len);
2846 try q.ensureCapacity(a.len());
2847 try r.ensureCapacity(b.len());
28482848 var mq = q.toMutable();
28492849 var mr = r.toMutable();
2850 const limbs_buffer = try q.allocator.alloc(Limb, calcDivLimbsBufferLen(a.limbs.len, b.limbs.len));
2850 const limbs_buffer = try q.allocator.alloc(Limb, calcDivLimbsBufferLen(a.len(), b.len()));
28512851 defer q.allocator.free(limbs_buffer);
28522852 mq.divFloor(&mr, a.toConst(), b.toConst(), limbs_buffer);
28532853 q.setMetadata(mq.positive, mq.len);
......@@ -2860,11 +2860,11 @@ pub const Managed = struct {
28602860 ///
28612861 /// Returns an error if memory could not be allocated.
28622862 pub fn divTrunc(q: *Managed, r: *Managed, a: *const Managed, b: *const Managed) !void {
2863 try q.ensureCapacity(a.limbs.len);
2864 try r.ensureCapacity(b.limbs.len);
2863 try q.ensureCapacity(a.len());
2864 try r.ensureCapacity(b.len());
28652865 var mq = q.toMutable();
28662866 var mr = r.toMutable();
2867 const limbs_buffer = try q.allocator.alloc(Limb, calcDivLimbsBufferLen(a.limbs.len, b.limbs.len));
2867 const limbs_buffer = try q.allocator.alloc(Limb, calcDivLimbsBufferLen(a.len(), b.len()));
28682868 defer q.allocator.free(limbs_buffer);
28692869 mq.divTrunc(&mr, a.toConst(), b.toConst(), limbs_buffer);
28702870 q.setMetadata(mq.positive, mq.len);
......@@ -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.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}