bn: fix iaddn sign issue. see indutny/bn.js#216.

bcoin-org · Mar 28, 2019 · 600eaa9 · 600eaa9
1 parent 8b42737
commit 600eaa9
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Showing 2 changed files with 6 additions and 1 deletion.
diff --git a/lib/js/bn.js b/lib/js/bn.js
@@ -186,7 +186,7 @@ class BN {
 
     // Possible sign change.
     if (this.negative !== 0) {
-      if (this.length === 1 && (this.words[0] | 0) < num) {
+      if (this.length === 1 && (this.words[0] | 0) <= num) {
         this.words[0] = num - (this.words[0] | 0);
         this.negative = 0;
         return this;

diff --git a/test/bn-test.js b/test/bn-test.js
@@ -411,6 +411,11 @@ describe('BN.js', function() {
           new BN(0).iaddn(0x4000000);
         });
       });
+
+      it('should reset sign if value equal to value in instance', function () {
+        const a = new BN(-1);
+        assert.equal(a.addn(1).toString(), '0');
+      });
     });
 
     describe('.sub()', () => {