Uncompressing Data(python) which is compressed using QT qUncompress function.

[Uday More]

I am compressing the data using the
inline QByteArray qCompress(const QByteArray& data, int compressionLevel = -1) function. I am able to compress the data and store it in the file. This compression is done using zlib default compression as mentioned in the documentation.

I am trying to decompress the data using python zlib API (decompress function), but I get the following error.
"zlib.error: Error -3 while decompressing data: incorrect header check"

Useful link : https://stackoverflow.com/questions/27440275/zlibdecompressor-throws-incorrect-header-check-exception

Can anyone please help how to proceed.

Qt 5.14.2
python 3.5.4

[Christian Ehrlicher]

@Uday-More said in Uncompressing Data(python) which is compressed using QT qUncompress function.:

Can anyone please help how to proceed.

See the documentation: "Note: If you want to use this function to uncompress external data that was compressed using zlib, you first need to prepend a four byte header to the byte array containing the data. The header must contain the expected length (in bytes) of the uncompressed data, expressed as an unsigned, big-endian, 32-bit integer."

Since you want to uncompress it externally you have to remove the first 4 bytes.