fitsio: systematically use io.ReadFull for reading padding bytes in decoding

[airnandez]

Avoid redundant checks of the length of data read when using io.ReadFull and use ioutil.Discard when reading the padding bytes, when decoding an image or table, so to avoid allocating a buffer.

No new tests written. All existing tests pass.

[airnandez]

Done both modifying the commit and submitted PR to licence repo.

[airnandez]

When you merge this PR to the lazy-image-loader branch, would you also be willing to merge that branch to master? In that way, when one does go get the improvements included in lazy-image-loader get installed and available.

There are still some API improvements that would be nice to have, but in my opinion they should go into another dedicated branch.

[sbinet]

thanks, but you changed the PR title (that's ok), I was talking about the commit message :)

[sbinet]

wrt the lazy-image-loader branch, I still need to implement the proper split of HDU into a HU and DU part. I am still officially on holidays but I'll give a stab next week.

[airnandez]

Understood about lazy-image-loader.

Regarding the commit message, my (admittedly) limited understanding of git is that it is not possible to change the commit message without changing the commit hash, which may have have consequences with this PR. I may be wrong, of course !

Is there a clean way to change the commit message I'm not aware of?

[sbinet]

your understanding of git is correct, this will change the commit hash :)

but if you push the new commit into this branch, the PR should be correctly updated. (and I'll cherry pick it in master.)

[airnandez]

Done. Thanks for the tip.

[sbinet]

ok... this was a bit convoluted (I prefer to have a rather linear git history) so I cherry picked your change and collected it as a1d964b.

thanks a lot!