Fixed warnings for Implicit narrowing conversion in compound assignment

[Jeffery-Wasty]

(Update 3/2/2022) While the below approach works, given that the use of readSkipBytes has changed, its no longer necessary to pass in a long. Thus the changes can be reduced to ensuring all involved types are int, avoiding any information loss.

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As seen here: https://github.com/microsoft/mssql-jdbc/security/code-scanning/1?query=ref%3Arefs%2Fheads%2Fmain, there is an implicit cast taking place in IOBuffer.java, that may lead to a loss of information. The solution was to first check if the long value bytesToSkip can be converted without information loss, and only allow addition to payloadOffset if this is true.

The reverse, that is widening payloadOffset to long, to accommodate bytesToSkip is not possible because of the many uses payloadOffset has throughout the file. Lines 7043 and 7049 in IOBuffer.java are good examples of this. Extensive reformatting is needed to change payloadOffset, while bytesToSkip can be checked with ease.

The function used to check if bytesToSkip is small enough, isSafeToConvert, uses a switch function even though it only has one case, this is to allow future cases to be added, if needed. Additionally, other values, besides long, can be passed in to convert, provided they are cast beforehand.

[tkyc]

I might be missing something here, but isn't an alternative like changing the "valueLength" param to int and then keeping the rest of the types in the method to int possible also? I only see the "readSkipBytes" method used in one place and it is taking in an int only, never a long

[Jeffery-Wasty]

You know what, I think you're absolutely right. I'm looking at the initial implementation, and it may have been necessary to pass in a long in that case, but that's no longer needed. This simplifies things greatly.