Added decodeMemoryLimit to Config to avoid memory leaks.

[b3n-l]

Per issue #475, we have potential for a memory leak, especially with Flate compressed data.

This PR adds an optional memory limit in the config, that can be used by any filter.

By default, the limit is set to 0 or unlimited.

This may not be the best way to propagate the setting, but I wanted it to be a configurable option, rather than hard-coded.

[k00ni]

Thank you for your pull request!

I am busy in the next 2 weeks, but will try to come back to you until end of November.

A few remarks:

• Does this PR closes Crashing PHP process through memory exhaustion when decompressing images. #475?
• If you add new properties/parameters, please use a type. For instance in Config for private $decodeMemoryLimit = 0;.

[b3n-l]

To confirm, this fixes the issue described in #475.

I made it optional, so that it didn't break compatibility if people are expecting to be able to deflate huge files.

I will update the PR with appropriate types.

[b3n-l]

Just a quick note,

I've investigated why it's failing the tests and it's because there's now the wrong number of arguments in some of the test calls. I'd appreciate input into the best format/structure for adding these arguments, as not all decompression methods will use/need them.

See decodeFilter as an example.

[k00ni]

I'd appreciate input into the best format/structure for adding these arguments, as not all decompression methods will use/need them.

There is no official statement. In my opinion the most important parameters should be first. Optional parameters always at the end.

If that doesn't help, can you please be more clear about what you mean?

[b3n-l]

I've updated the PR, and simplified it slightly too, I'm now happy with it.

I think this should fix the tests failing too.

[k00ni]

I took the liberty to fix remaining coding style issues. Any remarks @b3n-l?

If there are no objections I will merge it soon.

[b3n-l]

Thanks for that, all looks good to me.