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client/node_modules/elliptic/lib/elliptic/utils.js

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+'use strict';
+
+var utils = exports;
+var BN = require('bn.js');
+var minAssert = require('minimalistic-assert');
+var minUtils = require('minimalistic-crypto-utils');
+
+utils.assert = minAssert;
+utils.toArray = minUtils.toArray;
+utils.zero2 = minUtils.zero2;
+utils.toHex = minUtils.toHex;
+utils.encode = minUtils.encode;
+
+// Represent num in a w-NAF form
+function getNAF(num, w, bits) {
+  var naf = new Array(Math.max(num.bitLength(), bits) + 1);
+  naf.fill(0);
+
+  var ws = 1 << (w + 1);
+  var k = num.clone();
+
+  for (var i = 0; i < naf.length; i++) {
+    var z;
+    var mod = k.andln(ws - 1);
+    if (k.isOdd()) {
+      if (mod > (ws >> 1) - 1)
+        z = (ws >> 1) - mod;
+      else
+        z = mod;
+      k.isubn(z);
+    } else {
+      z = 0;
+    }
+
+    naf[i] = z;
+    k.iushrn(1);
+  }
+
+  return naf;
+}
+utils.getNAF = getNAF;
+
+// Represent k1, k2 in a Joint Sparse Form
+function getJSF(k1, k2) {
+  var jsf = [
+    [],
+    [],
+  ];
+
+  k1 = k1.clone();
+  k2 = k2.clone();
+  var d1 = 0;
+  var d2 = 0;
+  var m8;
+  while (k1.cmpn(-d1) > 0 || k2.cmpn(-d2) > 0) {
+    // First phase
+    var m14 = (k1.andln(3) + d1) & 3;
+    var m24 = (k2.andln(3) + d2) & 3;
+    if (m14 === 3)
+      m14 = -1;
+    if (m24 === 3)
+      m24 = -1;
+    var u1;
+    if ((m14 & 1) === 0) {
+      u1 = 0;
+    } else {
+      m8 = (k1.andln(7) + d1) & 7;
+      if ((m8 === 3 || m8 === 5) && m24 === 2)
+        u1 = -m14;
+      else
+        u1 = m14;
+    }
+    jsf[0].push(u1);
+
+    var u2;
+    if ((m24 & 1) === 0) {
+      u2 = 0;
+    } else {
+      m8 = (k2.andln(7) + d2) & 7;
+      if ((m8 === 3 || m8 === 5) && m14 === 2)
+        u2 = -m24;
+      else
+        u2 = m24;
+    }
+    jsf[1].push(u2);
+
+    // Second phase
+    if (2 * d1 === u1 + 1)
+      d1 = 1 - d1;
+    if (2 * d2 === u2 + 1)
+      d2 = 1 - d2;
+    k1.iushrn(1);
+    k2.iushrn(1);
+  }
+
+  return jsf;
+}
+utils.getJSF = getJSF;
+
+function cachedProperty(obj, name, computer) {
+  var key = '_' + name;
+  obj.prototype[name] = function cachedProperty() {
+    return this[key] !== undefined ? this[key] :
+      this[key] = computer.call(this);
+  };
+}
+utils.cachedProperty = cachedProperty;
+
+function parseBytes(bytes) {
+  return typeof bytes === 'string' ? utils.toArray(bytes, 'hex') :
+    bytes;
+}
+utils.parseBytes = parseBytes;
+
+function intFromLE(bytes) {
+  return new BN(bytes, 'hex', 'le');
+}
+utils.intFromLE = intFromLE;
+