bn.js - npm Package Compare versions

Comparing version 0.15.1 to 0.15.2

lib/bn.js

@@ -620,4 +620,3 @@ // Utils
 
-// Multiply `this` by `num` and store data in out
-BN.prototype.mulTo = function mulTo(num, out) {
+BN.prototype._smallMulTo = function _smallMulTo(num, out) {
   out.sign = num.sign !== this.sign;
@@ -657,2 +656,52 @@ out.length = this.length + num.length;
 
+BN.prototype._bigMulTo = function _bigMulTo(num, out) {
+  out.sign = num.sign !== this.sign;
+  out.length = this.length + num.length;
+
+  var carry = 0;
+  var hncarry = 0;
+  for (var k = 0; k < out.length - 1; k++) {
+    // Sum all words with the same `i + j = k` and accumulate `ncarry`,
+    // note that ncarry could be >= 0x3ffffff
+    var ncarry = hncarry;
+    hncarry = 0;
+    var rword = carry & 0x3ffffff;
+    var maxJ = Math.min(k, num.length - 1);
+    for (var j = Math.max(0, k - this.length + 1); j <= maxJ; j++) {
+      var i = k - j;
+      var a = this.words[i] | 0;
+      var b = num.words[j] | 0;
+      var r = a * b;
+
+      var lo = r & 0x3ffffff;
+      ncarry = (ncarry + ((r / 0x4000000) | 0)) | 0;
+      lo = (lo + rword) | 0;
+      rword = lo & 0x3ffffff;
+      ncarry = (ncarry + (lo >>> 26)) | 0;
+
+      hncarry += ncarry >>> 26;
+      ncarry &= 0x3ffffff;
+    }
+    out.words[k] = rword;
+    carry = ncarry;
+    ncarry = hncarry;
+  }
+  if (carry !== 0) {
+    out.words[k] = carry;
+  } else {
+    out.length--;
+  }
+
+  return out.strip();
+};
+
+BN.prototype.mulTo = function mulTo(num, out) {
+  var res;
+  if (this.length + num.length < 63)
+    res = this._smallMulTo(num, out);
+  else
+    res = this._bigMulTo(num, out);
+  return res;
+};
+
 // Multiply `this` by `num`
@@ -659,0 +708,0 @@ BN.prototype.mul = function mul(num) {

package.json

 {
   "name": "bn.js",
-  "version": "0.15.1",
+  "version": "0.15.2",
   "description": "Big number implementation in pure javascript",
@@ -5,0 +5,0 @@ "main": "lib/bn.js",

test/bn-test.js

 var assert = require('assert');
 var BN = require('../').BN;
+var fixtures = require('./fixtures');
 
@@ -215,2 +216,10 @@ describe('BN', function() {
 
+  it('should regress mul big numbers', function() {
+    var q = fixtures.dhGroups.p17.q;
+    var qs = fixtures.dhGroups.p17.qs;
+
+    var q = new BN(q, 16);
+    assert.equal(q.sqr().toString(16), qs);
+  });
+
   it('should imul numbers', function() {
@@ -217,0 +226,0 @@ var a = new BN('abcdef01234567890abcd', 16);

test/red-test.js

 var assert = require('assert');
 var BN = require('../').BN;
+var fixtures = require('./fixtures');
 
@@ -4,0 +5,0 @@ describe('BN.js/Reduction context', function() {

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Improved metrics

Total package byte prevSize

80855

increased by27.35%

Number of package files

9

increased by28.57%

Lines of code

2393

increased by16.17%

No dependency changes