code review 155063: An asked-for-in #go-nuts extension to quickly create a...

An asked-for-in #go-nuts extension to quickly create a repeated
	copy of a string or a byte array.
        strings.Repeat("-", 50)
	bytes.Repeat(b, 99)

[dga, 2009-11-16 02:42:54]

Hello rsc,

I'd like you to review the following change.

[rsc, 2009-11-16 16:05:20]

Thanks for taking the time to do this.
One comment below on algorithm.
Test looks great.

Please drop similar code into the bytes package--
we try to keep the two mostly in sync.

Also, please send a separate AUTHORS/CONTRIBUTORS
change list as per http://golang.org/doc/contribute.html#copyright

Thanks again.
Russ

http://codereview.appspot.com/155063/diff/1006/16
File src/pkg/strings/strings.go (right):

http://codereview.appspot.com/155063/diff/1006/16#newcode194
src/pkg/strings/strings.go:194: ns += s
This will end up making the loop quadratic in its allocation.
Instead I think you want you to do something like

b := make([]byte, len(s)*count);

and then use a nested for loop to copy the bytes in
count times and return string(b).

[dga, 2009-11-16 16:42:14]

On 2009/11/16 16:05:20, rsc wrote:
> Please drop similar code into the bytes package--
> we try to keep the two mostly in sync.

Is it cool to use a different function from package bytes in a test for
bytes.Repeat?  (bytes.Equal).  Or is it preferred to cast the result back to a
string and use equal?

> Also, please send a separate AUTHORS/CONTRIBUTORS
> change list as per http://golang.org/doc/contribute.html#copyright

Whoops.  Done.  I've left a question in there about whether or not CMU's signed
the agreement or not.  I've done this on my own time, but if CMU has signed the
agreement, I'll assign the changes to them and keep the authors list clean.
Changes to authors/contributors uploaded as 154161

[dga, 2009-11-16 16:46:25]

On 2009/11/16 16:05:20, rsc wrote:
> Please drop similar code into the bytes package--
> we try to keep the two mostly in sync.

Done.

[rsc, 2009-11-16 20:00:42]

LGTM

thanks.
i'll submit shortly and then hg sync will update your client

[rsc, 2009-11-16 20:40:02]

*** Submitted as http://code.google.com/p/go/source/detail?r=56f4dc2af1fa ***

	An asked-for-in #go-nuts extension to quickly create a repeated
	copy of a string or a byte array.
        strings.Repeat("-", 50)
	bytes.Repeat(b, 99)

R=rsc
http://codereview.appspot.com/155063

Committer: Russ Cox <rsc@golang.org>