Question

Let’s say I would like to compress the following list and keep the compressed version in RAM:

List = lists:seq(1,100000).

The example provided in the official documentation doesn’t work for me – I get the error for unbound variable Read and I do not understand what it is used for (is it a function or a variable?).

I have tried to search on the web, but the only thing that I have found is related to decompressing files.

So, the question is: How can I compress the list List and decompress it back with the help of zlib in Erlang? How can I see what amount of memory is consumed by the List and its compressed counterpart?

Answer 1

You can compress the data in the following manner:

Z=zlib:open(),
zlib:deflateInit(Z),
CData=zlib:deflate(Z2, lists:seq(1,100), finish),
zlib:deflateEnd(Z).

To decompress the data you can do:

Z=zlib:open(),
zlib:inflateInit(Z),
Data=zlib:Inflate(Z, CData),
zlib:inflateEnd(Z).

You can just figure out the size by checking CData.