_ucmp() fails for specific contents

[ktrzeciaknubisa]

Since we're getting rid of base64 encoding when passing strings/buffers to _cmp() / _ucmp() (due to #508) I've encountered one file for which _ucmp() fails (returns false).

This is a xml file and comes from one of ghost's sub modules (sax). It's better to download the file rather than copy/paste to editor.

jx install sax@0.4.2
# the file is under node_modules/sax/examples/big-not-pretty.xml

Then the following code shows the problem:

var jxt = process.binding('jxutils_wrap');
var fs = require('fs');

var input = fs.readFileSync('./node_modules/sax/examples/big-not-pretty.xml');
var c = jxt._cmp(input);
var output = jxt._ucmp(c);

if (!output)
  jxcore.utils.console.error('Empty output!');

---

Not really sure what is the problem. I was stripping the file to make it smaller, and so I arrived to the point of this big-not-pretty2.zip (the file is compressed in order to preserve binary format - unzip before use), where removing single (literally any) character from file contents makes the above code work. But the problem is not related to file size, because _ucmp() is working with much bigger files.

[ktrzeciaknubisa]

I've also found, that the following files from jxcore repo also have this problems. What came to my eyes is that each of those files contain series of repetitive strings/blocks, for example:

1. ./deps/mozjs/src/tests/js1_5/Regress/regress-229006.js

   has multiple empty lines following each other

2. ./deps/mozjs/src/jit-test/tests/basic/bug586917 and
   ./deps/mozjs/src/tests/js1_5/Regress/regress-311629.js

       try {} catch (e) {}
       try {} catch (e) {}
       try {} catch (e) {}
       try {} catch (e) {}

3. ./deps/mozjs/src/tests/js1_5/Regress/regress-229006.js

   eval('+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +  ...

4. ./deps/npm/node_modules/request/node_modules/form-data/node_modules/combined-stream/test/fixture/file1.txt

   101010101010101010101010101010101010101010101010101010101010
   

5. ./deps/npm/node_modules/request/node_modules/form-data/node_modules/combined-stream/test/fixture/file2.txt

   2020202020202020202020202020202020202020202020202020202020202
   

6. ./test/fixtures/elipses.txt

   ………………………………………………………………………………
   

   ---

   The xml mentioned earlier (big-not-pretty.xml) also contains repetitive blocks.