Fixed wrong offset for d_buf (closes #78)

lib/zlib/deflate.js

@@ -1364,9 +1364,16 @@ function deflateInit2(strm, level, method, windowBits, memLevel, strategy) {
   s.lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
 
   s.pending_buf_size = s.lit_bufsize * 4;
+
+  //overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
+  //s->pending_buf = (uchf *) overlay;
   s.pending_buf = new utils.Buf8(s.pending_buf_size);
 
-  s.d_buf = s.lit_bufsize >> 1;
+  // It is offset from `s.pending_buf` (size is `s.lit_bufsize * 2`)
+  //s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
+  s.d_buf = 1 * s.lit_bufsize;
+
+  //s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
   s.l_buf = (1 + 2) * s.lit_bufsize;
 
   s.level = level;

test/deflate.js

@@ -9,6 +9,10 @@ var zlib = require('zlib');
 var pako    = require('../index');
 var helpers = require('./helpers');
 var testSamples = helpers.testSamples;
+var assert  = require('assert');
+var fs      = require('fs');
+var path    = require('path');
+
 
 
 var samples = helpers.loadSamples();
@@ -202,3 +206,17 @@ describe('Deflate dictionary', function () {
     }
   });
 });
+
+
+describe('Deflate issues', function () {
+
+  it('#78', function () {
+    var data = fs.readFileSync(path.join(__dirname, 'fixtures', 'issue_78.bin'));
+    var options = { level: 6, memLevel: 1 };
+
+    var deflatedPakoData = pako.deflate(data, options);
+    var deflatedZlibData = zlib.deflateSync(data, options);
+
+    assert.equal(deflatedPakoData.length, deflatedZlibData.length);
+  });
+});