Using Kotlin require function to check for number range and maximum attempts

[jelle82]

Kotlin has some nice functions for checking and throwing exceptions based on a predicate.

I think the proposed changes makes the code more idiomatic Kotlin and is more concise.

[jelle82]

Even if this pull request is not merged:

There might be some a test case not covered, when I change this line require(increment <= alphabet.length) { "Reached max attempts to re-generate the ID" } into require(increment < alphabet.length) { "Reached max attempts to re-generate the ID" }, all the tests still pass.

I could look into this also, if you want and try to write a test for it.

[kevinxmorales]

Even if this pull request is not merged:

There might be some a test case not covered, when I change this line require(increment <= alphabet.length) { "Reached max attempts to re-generate the ID" } into require(increment < alphabet.length) { "Reached max attempts to re-generate the ID" }, all the tests still pass.

I could look into this also, if you want and try to write a test for it.

This check directly ported from the sqids specification
The maxBlockList test is a good example of what this limit aims to do, try as hard as possible to continually produce new ids in the case that the block list prevents a generated id from being used. In the example you gave, we would give up on trying to produce the id 1 less times than we normally would. I think to properly test that, you'd need to have an alphabet of length x and a block list of length x - 1 to see the importance of the line as it is written. I think its worth a test case both here and in the sqids-spec.

[kevinxmorales]

This change is great! If you notice anything else that might not be idiomatic Kotlin, feel free to make more changes. Highly appreciated