FAQ Database Discussion Community


Is zlib Type0 header data should be included in adler checksum calculation?

zlib,checksum
When calculating the Adler-32 checksum of uncompressed data in zlib format, should it include Type 0 (uncompressed data) data as well?

Zip file encryption readable by some Zip clients, not others

objective-c,zip,zlib
I'm investigating a bug report on my open source UnzipKit project. Basically, when writing files encrypted with a password to a Zip file, the resulting archives are readable by some Zip clients, and not others. UnzipKit writes the password as a UTF-8 string, using the MiniZip wrapper around zlib, which...

compressing multicast packets with zlib library

c,zlib
I am listening packets from a multicast ip port and trying to compress that packet using zlib library, ( want to know the compression ratio from zlib in the live packets, as this is the requirement from our client). I have implemented zlib compression code as below, but length of...

How can I deflate zlib data and find out how many input bytes there were?

git,rust,zlib
I'm building a git clone implementation in Rust. I've gotten to the part where I need to parse the packfile to create the index, and I'm almost done parsing it. Each object in the packfile consists of a header (Which I'm already parsing correctly) followed by the contents which are...

zlib uncompress a .zip file [duplicate]

c++,zlib
This question already has an answer here: Simple way to unzip a .zip file using zlib 2 answers So I have an array of bytes that I would like to decompress using the uncompress function in zlib but it always returns Z_DATA_ERROR. So my question is, does zlib support...

uncompress error when using zlib

c,zlib
It could be a silly question. When I tried to uncompress a compressed data in memory, got error. Here is the code. #include <zlib.h> #include <stdio.h> #include <stdlib.h> int readFile(char *fname, char buf[]) { FILE *fp = fopen(fname, "rb"); if (fp == NULL) { printf("Failed to open %s\n", fname); exit(0);}...

Deterministic hashing of Python 3 strings with adler32

python,python-3.x,hash,zlib
I read here the following: Note: To generate the same numeric value across all Python versions and platforms use adler32(data) & 0xffffffff. I am hoping to apply this to a string of the form: "S89234IX", but when I do so, I get: > zlib.adler32("S89234IX") --------------------------------------------------------------------------- TypeError Traceback (most recent call...

Python: unpack android backup?

android,python,backup,tar,zlib
I'd like to unpack an Android backup file using python. According to http://nelenkov.blogspot.com/2012/06/unpacking-android-backups.html an unencryted adb file can be decompressed using dd if=mybackup.ab bs=24 skip=1|openssl zlib -d > mybackup.tar and tar xvf mybackup.tar Can these can be done in python? Python has zlib, gzip and tarfile, which seem as if...

How to use multiple threads for zlib compression

multithreading,compression,zlib
I have a large chunk of data (around 2 GB) that needs to be compressed using zlib (deflate()). I am currently reading 500 kb of data at 1 go, compressing it and writing it to my output file. With 1 thread, everything is fine. The data is compressed and I...

How to use deflate/inflate SetDictionary with raw deflate/inflate?

c,compression,zlib,decompression,deflate
I'm trying to understand the functionality of raw deflate when we use dictionary. I'm aware of the following. 1. When we use a dictionary, the application should provide the same dictionary for deflate() and inflate(). 2. When doing raw deflate, this function must be called either before any call of...

Write zlib compressed utf8 data to a file

python,utf-8,zlib
I have a file with data encoded in utf-8. I would like to read the data, remove whitespaces, separate words with a newline, compress the entire content and write them to a file. This is what I am trying to do : with codecs.open('1020104_4.utf8', encoding='utf8', mode='r') as fr : data...

What's wrong with this use of java Deflater/Inflater with a dictionary

java,zlib
I'm trying to use Inflater and Deflater with a dictionary but it's not working. When I run this simple test program: import java.io.*; import java.util.*; import java.util.zip.*; public class DictTest { public static void main(String[] args) throws Exception { final int level = 9; final boolean nowrap = true; //...

Implicit conversion loses integer precision in ZLib compression method

ios,objective-c,zlib,nsinteger
Implicit conversion loses integer precision: 'unsigned long' to 'uInt' (aka 'unsigned int') I am trying to update my application from 32bit to 64bit, since changing the architecture I have recived an error as decribed above. I have a method that takes NSData that is zlib compressed and returns the...

Does zlib's “uncompress” preserve the data's original endianness, or does it do an endian conversion?

zlib,endianness,uncompress
I am working with legacy C++ code that accesses two-byte integer data compressed in a sqlite database. The code uses zlib's uncompress function to extract the data, which comes out on my little-endian machine as little-endian values. To allow for the possibility that this code may be ported to big-endian...

Decode gzip compressed and base64 encoded data to a readable format

python,python-3.x,gzip,zlib
Trying to decode gzip compressed and base64 encoded data to a readable format in Python3.4. import base64 import zlib original_data = '...jU2X0NCQ19TSEEAAAABAAA=' #Data cut short. decoded64 = base64.b64decode(original_data) #format:b'\x16xe\x94...\xae\x9a\...' final_decoded = zlib.decompress(decoded64) print(final_decoded) Been getting: "Error -2 while preparing to decompress data: inconsistent stream state." Not sure what I'm doing...

NodeJS: zlib.gunzip() on file contents returns Error: incorrect header check

javascript,node.js,gzip,zlib,fs
My script takes file data, interprets it, and spits it out in a different format. The user can input a URL or upload a file, and the file refence for either of these can be XML or GZIP (which I then decompress). What works: Parsing XML + GZIP from URL...

zlib inflate returning a buffer error

c++,zip,gzip,zlib,inflate
I'm trying to decompress a zip file using zlib (without using any extension or 3rd party). Initially, the src_len is 48756255, and the dest_len is 49209890. The first pass in the while loop is fine: err is Z_OK and the second pass through starts. On the second pass, no matter...

Exception during integration test in new jhipster app with mongodb

java,mongodb,zlib,jhipster
When i create new jhipster app and run integration tests i have such exception: Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.mongodb.Mongo]: Factory method 'mongo' threw exception; nested exception is de.flapdoodle.embed.process.exceptions.DistributionException: java.io.EOFException: Unexpected end of ZLIB input stream at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189) ~[spring-beans-4.1.6.RELEASE.jar:4.1.6.RELEASE]...

Compress data to chunks using Zlib

c,zlib
I want to compress a file with size > 50mb with zlib. But I want the compressed file to be in chunks (for example, 32Kb chunks). I don't want to read 32Kb of uncompressed file and compress it. The compressed file should contain 32kb compressed chunks. Compression should be reset...

How to implement zlib's crc32_combine() function in PHP?

php,zlib,crc32
I'm trying to create crc32_combine function in PHP but I don't fully understand it's source in zlib library. I need this: <?php $crc_a = crc32('a'); $crc_aa = crc32('aa'); $crc_aa === crc32_combine($crc_a, $crc_a, 1); // should result in TRUE What I have: <?php define('GF2_DIM', 32); function gf2_matrix_times($mat, $vec) { $sum =...

Node: zlib.gunzip works, but not zlib.inflate?

javascript,node.js,compression,zip,zlib
Why is it that GZIP files I upload can be decompressed fine with zlib.gunzip(), but ZIP files uploaded result in an [Error: incorrect header check] errno: -3, code: 'Z_DATA_ERROR' error from zlib.inflate(), using the following code? if (req.body.compression == 'GZIP') { zlib.gunzip(body, function(err, dezipped) { if (typeof dezipped != 'undefined')...

How to insert type 0 block along with data in zlib

c,linux,header,zlib
I have to insert uncompressed data in between the compressed data bytes. Type 0 header in zlib allows me to do that. But How can i do that ? any clues ?

Android Java - NumberFormatException while parsing “76”

java,android,zlib,numberformatexception,parseint
I'm working on an Android app using zbar to decode QR. The structure of the QR is: "SpecificPrefix/[Number]". String d = sym.getData(); // I get the QR text from the symbol if(d.startsWith(QRUri)) { // QRUri is a string const containig the prefix int id; try { Log.d("NOT", "QR Subst \""...

Link error: Installing boost zlib filters using NuGet in Visual Studio (2012)

c++,visual-studio-2012,boost,nuget,zlib
I've installed these packages: boost boost-vc110 boost_iostreams_zlib zlib But the linker is unable to find the required lib: 2>LINK : fatal error LNK1104: cannot open file 'libboost_zlib-vc110-mt-1_58.lib' Is there a way to fix this problem manually by changing the file name or am I still missing a package?...