bn: fix Red#imod

indutny · Jun 6, 2018 · d87ed90 · d87ed90
1 parent 98ac84e
commit d87ed90
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/lib/bn.js b/lib/bn.js
@@ -3169,7 +3169,10 @@
 
  Red.prototype.imod = function imod (a) {
  if (this.prime) return this.prime.ireduce(a)._forceRed(this);
- return a.umod(this.m)._forceRed(this);
+
+ var mod = a.umod(this.m)._forceRed(this);
+ if (mod !== a) mod.copy(a);
+ return a;
  };
 
  Red.prototype.neg = function neg (a) {

diff --git a/test/red-test.js b/test/red-test.js
@@ -262,4 +262,13 @@ describe('BN.js/Reduction context', function () {
  red.prime.split(input, output);
  assert.equal(input.cmp(output), 0);
  });
+
+ it('imod should change host object', function () {
+ var red = BN.red(new BN(13));
+ var a = new BN(2).toRed(red);
+ var b = new BN(7).toRed(red);
+ var c = a.redIMul(b);
+ assert.equal(a.toNumber(), 1);
+ assert.equal(c.toNumber(), 1);
+ });
 });