1  /*jshint node:true */
 2  'use strict';
 3  var Buffer = require('buffer').Buffer; // browserify
 4  var SlowBuffer = require('buffer').SlowBuffer;
 5  
 6  module.exports = bufferEq;
 7  
 8  function bufferEq(a, b) {
 9  
10    // shortcutting on type is necessary for correctness
11    if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
12      return false;
13    }
14  
15    // buffer sizes should be well-known information, so despite this
16    // shortcutting, it doesn't leak any information about the *contents* of the
17    // buffers.
18    if (a.length !== b.length) {
19      return false;
20    }
21  
22    var c = 0;
23    for (var i = 0; i < a.length; i++) {
24      /*jshint bitwise:false */
25      c |= a[i] ^ b[i]; // XOR
26    }
27    return c === 0;
28  }
29  
30  bufferEq.install = function() {
31    Buffer.prototype.equal = SlowBuffer.prototype.equal = function equal(that) {
32      return bufferEq(this, that);
33    };
34  };
35  
36  var origBufEqual = Buffer.prototype.equal;
37  var origSlowBufEqual = SlowBuffer.prototype.equal;
38  bufferEq.restore = function() {
39    Buffer.prototype.equal = origBufEqual;
40    SlowBuffer.prototype.equal = origSlowBufEqual;
41  };