Re: [PATCH 2/2] vec: Add array_slice::bsearch

[Martin Jambor <mjambor@suse.cz>]

Hi,

On Fri, Aug 26 2022, Richard Sandiford wrote:
> Richard Biener <rguenther@suse.de> writes:
>>> Am 26.08.2022 um 18:40 schrieb Martin Jambor <mjambor@suse.cz>:
>>> 
>>> Hi,
>>> 
>>> This adds a method to binary search in a sorted array_slice.
>>> 
>>> The implementation is direct copy of vec:bsearch.  Moreover, to only
>>> copy it once and not twice, I used const_cast in the non-const
>>> variants to be able to use the const variants.  I hope that is
>>> acceptable abuse of const_cast but I'll be happy to change that if
>>> not.
>>> 
>>> Bootstrapped and tested along code that actually uses it on
>>> x86_64-linux.  OK for trunk?
>>
>> Can you avoid the copying by using array slice bsearch from the vec<> bsearch?
>
> IMO it would be better to transition to using <algorithm> routines
> for this kind of thing (for new code).  In this case that would be
> std::lower_bound.
>
> Using std::lower_bound is more convenient because it avoids the void *
> thing (you can use lambdas to capture any number of variables instead)
> and because it works on subranges, not just whole ranges.
>

OK, I can use std::lower_bound with simple lambdas too.  The semantics
of returning the first matching a criterion actually allows me to use it
one more time.

Martin