On Wed, Jun 07, 2023 at 09:28:29PM +0100, Conor Dooley wrote: > From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> > > While expanding on the comments in the ISA string parsing code, I > noticed that the conditional decrement of `isa` at the end of the loop > was a bit odd. > The parsing code expects that at the start of the for loop, `isa` will > point to the first character of the next unparsed extension. > However, depending on what the next extension is, this may not be true. > Unless the next extension is a multi-letter extension preceded by an > underscore, `isa` will either point to the string's null-terminator or > to the first character of the next extension, once the switch statement > has been evaluated. > Obviously incrementing `isa` at the end of the loop could cause it to > increment past the null terminator or miss a single letter extension, so > `isa` is conditionally decremented, just so that the loop can increment > it again. > > It's easier to understand the code if, instead of this decrement + > increment dance, we instead use a while loop & rely on the handling of > individual extension types to leave `isa` pointing to the first > character of the next extension. > As already mentioned, this won't be the case where the following > extension is multi-letter & preceded by an underscore. To handle that, > invert the check and increment rather than decrement. > Hopefully this eliminates a "huh?!?" moment the next time somebody tries > to understand this code. > > Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx> > Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> > --- Reviewed-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx>
