you probably crate more readable code

You misspelled the word 'fuck'.

Nah, it's fine. I just can't see!

Yeah, didn't see that 'if' there. My fault.

Nope. Sorry about that gentlemen, totally didn't see the 'if' there. My fault. I would still do a check to make sure your allocation routine isn't getting called with a zero.

Of course he's got some kind of memory corruption.

Dude, that stuff doesn't matter. You can't do this:

char* inputBufferSubset = allocCharBuffer(inputBufferLength);
memcpy(inputBufferSubset, &input[i-inputBufferLength], inputBufferLength);

inputBufferLength starts out at 0. You're overwriting memory you're not supposed to.

Doesn't matter what happens later. He's modifying memory that's not been allocated properly.

char* inputBufferSubset = allocCharBuffer(inputBufferLength);
memcpy(inputBufferSubset, &input[i-inputBufferLength], inputBufferLength);

Your problem is here:

char* inputBufferSubset = allocCharBuffer(inputBufferLength);

And inputBufferLength starts out at 0. Anything else that happens in the program is up for grabs because you might be overwriting some data structure used by the allocator or something.

It looks like inputBufferLength is starting out at zero. And then allocCharBuffer(inputBufferLength) gets called which calls malloc with a length of zero. I guess malloc returns the pointer anyway. Yep I just tested it and it does on my system too.

Here's some junk about it: https://bytes.com/topic/c/answers/578467-what-malloc-0-should-returns

It looks like if you're running debian it's already fixed so you just have to update with apt:

https://www.debian.org/security/2016/dsa-3481