node/test/parallel/test-zlib-from-multiple-huge-gzip.js

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// test unzipping a file that was created by concatenating multiple gzip
// streams.

var common = require('../common');
var assert = require('assert');
var zlib = require('zlib');

var util = require('util');

var HUGE = 64 * 1024;

var originalBuffer = new Buffer(3 * HUGE);
var originalOffset = 0;

var gzipBuffer = new Buffer(3 * HUGE);
var gzipOffset = 0;

function getRandomLetter() {
  return (Math.random() * (122 - 97)) + 97;
}

function generateHugeStream() {
  var buffer = new Buffer(HUGE);
  for (var i = 0; i < HUGE; i++)
    buffer.writeUInt8(getRandomLetter(), i);

  buffer.copy(originalBuffer, originalOffset);
  originalOffset += HUGE;

  return buffer;
}

function gzipAppend(data) {
  data.copy(gzipBuffer, gzipOffset);
  gzipOffset += data.length;
}

function writeGzipStream(text, cb) {
  var gzip = zlib.createGzip();
  gzip.on('data', gzipAppend);
  gzip.write(text, function() {
    gzip.flush(function() {
      gzip.end(function() {
        cb();
      });
    });
  });
}

writeGzipStream(generateHugeStream(), function() {
  writeGzipStream(generateHugeStream(), function() {
    writeGzipStream(generateHugeStream(), function() {
      var gunzip = zlib.createGunzip();
      var gunzippedData = new Buffer(3 * HUGE);
      var gunzippedOffset = 0;
      gunzip.on('data', function (data) {
        data.copy(gunzippedData, gunzippedOffset);
        gunzippedOffset += data.length;
      });
      gunzip.on('end', function() {
        var gunzippedStr = gunzippedData.toString('utf8', 0, gunzippedOffset);
        var originalStr  = originalBuffer.toString('utf8', 0, 3 * HUGE);

        assert.equal(gunzippedStr, originalStr);
      });

      gunzip.write(gzipBuffer.slice(0, gzipOffset), 'binary', function() {
        gunzip.end();
      });
    });
  });
});