Re: [PATCH]kconfig:mconf: avoid unneeded memcpy

From: Wang YanQing
Date: Sun Oct 06 2013 - 11:19:06 EST


On Sun, Oct 06, 2013 at 01:57:15AM +0800, Wang YanQing wrote:
> In function update_text we assign jump key label
> per page (1)-(9) cycled, and use three space char
> as the header after k exceed JUMP_NB.
>
> We don't need to call memcpy with header of three
> space char, because it changes nothing, it just
> copy what was there.
>
> I don't think we need to clear old jump key label in
> current implementation, I can't image out any case
> which a search result could change its jump key label,
> unless user search new string, but then we will re-assign
> jump key label, and it will be fix after that.
>
> Signed-off-by: Wang YanQing <udknight@xxxxxxxxx>
> ---
> scripts/kconfig/mconf.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/scripts/kconfig/mconf.c b/scripts/kconfig/mconf.c
> index 2c39631..ff9d737 100644
> --- a/scripts/kconfig/mconf.c
> +++ b/scripts/kconfig/mconf.c
> @@ -379,11 +379,8 @@ static void update_text(char *buf, size_t start, size_t end, void *_data)
> data->keys[k] = key;
> data->targets[k] = pos->target;
> k++;
> - } else {
> - sprintf(header, " ");
> + memcpy(buf + pos->offset, header, sizeof(header) - 1);
> }
> -
> - memcpy(buf + pos->offset, header, sizeof(header) - 1);
> }
> }
> data->keys[k] = 0;
> --
> 1.7.12.4.dirty

Hi all, please ignore this patch.

I image out that we need to clear old jump label when we run
make menuconfig in a x11 terminal with high resolution that
could show more than 9 item in one page.

Sorry.
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