Comments on: “import zlib” vs. .NET Framework

By: Fuzzyman

Fuzzyman — Sat, 02 Jun 2007 13:21:04 +0000

Unfortunately the example posted by Max doesn’t work – because the StreamReader loses information when you read the compressed data in as a string ‘StreamReader(ms).ReadToEnd()’.

The best solution (IMHO) is to leave the compressed data as bytes (which is what it is).

http://www.ironpython.info/index.php/Compression_with_DeflateStream

By: Max

Max — Wed, 23 Aug 2006 09:42:46 +0000

This is untested, but it should do exactly what you want in a much more concise way. Note that you can actually leave out the explicit Close statements and rely on the GC to reclaim the memory and save yourself 3 further lines of code instantly . In fact, if you do that you can write decompress in one line .

from System.IO import StreamReader, MemoryStream
from System.IO.Compression import CompressionMode, DeflateStream
from System.Text import Encoding

def decompress(data):
gz = DeflateStream(MemoryStream(Encoding.ASCII.GetBytes(data)), CompressionMode.Decompress)
str = StreamReader(gz).ReadToEnd()
gz.Close()
return str

def compress(data):
ms = MemoryStream()
gz = DeflateStream(ms, CompressionMode.Compress, True)
bytes = Encoding.ASCII.GetBytes(data)
gz.Write(bytes, 0, bytes.Length)
gz.Close()
string = StreamReader(ms).ReadToEnd()
ms.Close()
return string

By: casey

casey — Mon, 12 Jun 2006 18:59:44 +0000

IronPython really needs to provide simpler class and namespace names, maybe some aliases or an emulation of the sys, os, and other essentials. OTW it is still almost as much typing as C#!

By: Calvin Spealman

Calvin Spealman — Tue, 06 Jun 2006 01:11:14 +0000

You shouldn’t look at this as something that is so much harder to do in IronPython than CPython. Instead, as Fredrik pointed out, its a much simpler implementation of zlib than that for CPython, so wrap this up in a zlib for .Net and everyone one else can reap the benefits of your work!

By: Lawrence Oluyede

Lawrence Oluyede — Mon, 05 Jun 2006 14:21:16 +0000

Ouch. That means it can’t be shortened

By: Mathieu Fenniak

Mathieu Fenniak — Mon, 05 Jun 2006 13:42:57 +0000

Lawrence – The .NET version of this code does use the System.IO.Compression.DeflateStream class.

By: Lawrence Oluyede

Lawrence Oluyede — Mon, 05 Jun 2006 13:35:57 +0000

AFAIK with http://msdn2.microsoft.com/en-us/system.io.compression.aspx it should be shorter.

By: Fredrik

Fredrik — Mon, 05 Jun 2006 07:02:16 +0000

On the other hand, the source code for the zlib module is 1000 lines long, so 45 lines for a partial implementation isn’t all that bad…