[PATCH]kconfig:mconf: avoid unneeded memcpy

[PATCH]kconfig:mconf: avoid unneeded memcpy

[Wang YanQing]

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@gmail.com>
---
 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

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

[Wang YanQing]

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@gmail.com>
> ---
>  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.