[PATCH] lib: string: implement mempcpy

[PATCH] lib: string: implement mempcpy

[Ahmad Fatoum]

mempcpy(3) is a GNU libc extension that like stpcpy returns not the
start of the destination buffer, but the first byte after its end.

Provide it as it is useful when concatenating buffers or known-size
strings.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
v1 -> v2:
  - split off function from series using it. Other series needs
    commits reordered.
---
 include/string.h | 1 +
 lib/string.c     | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/string.h b/include/string.h
index 2cc727fd1d7a..596440ca8164 100644
--- a/include/string.h
+++ b/include/string.h
@@ -4,6 +4,7 @@
 
 #include <linux/string.h>
 
+void *mempcpy(void *dest, const void *src, size_t count);
 int strtobool(const char *str, int *val);
 char *strsep_unescaped(char **, const char *);
 char *stpcpy(char *dest, const char *src);
diff --git a/lib/string.c b/lib/string.c
index fd4d7da10a7c..edd36da4d4f2 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -603,6 +603,11 @@ void *__memcpy(void * dest, const void *src, size_t count)
 	__alias(__default_memcpy);
 #endif
 
+void *mempcpy(void *dest, const void *src, size_t count)
+{
+	return memcpy(dest, src, count) + count;
+}
+EXPORT_SYMBOL(mempcpy);
 
 #ifndef __HAVE_ARCH_MEMMOVE
 /**
-- 
2.30.2

Re: [PATCH] lib: string: implement mempcpy

[Sascha Hauer]

On Tue, Nov 01, 2022 at 07:43:10AM +0100, Ahmad Fatoum wrote:
> mempcpy(3) is a GNU libc extension that like stpcpy returns not the
> start of the destination buffer, but the first byte after its end.
> 
> Provide it as it is useful when concatenating buffers or known-size
> strings.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> v1 -> v2:
>   - split off function from series using it. Other series needs
>     commits reordered.

Applied, thanks

Sascha

> ---
>  include/string.h | 1 +
>  lib/string.c     | 5 +++++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/include/string.h b/include/string.h
> index 2cc727fd1d7a..596440ca8164 100644
> --- a/include/string.h
> +++ b/include/string.h
> @@ -4,6 +4,7 @@
>  
>  #include <linux/string.h>
>  
> +void *mempcpy(void *dest, const void *src, size_t count);
>  int strtobool(const char *str, int *val);
>  char *strsep_unescaped(char **, const char *);
>  char *stpcpy(char *dest, const char *src);
> diff --git a/lib/string.c b/lib/string.c
> index fd4d7da10a7c..edd36da4d4f2 100644
> --- a/lib/string.c
> +++ b/lib/string.c
> @@ -603,6 +603,11 @@ void *__memcpy(void * dest, const void *src, size_t count)
>  	__alias(__default_memcpy);
>  #endif
>  
> +void *mempcpy(void *dest, const void *src, size_t count)
> +{
> +	return memcpy(dest, src, count) + count;
> +}
> +EXPORT_SYMBOL(mempcpy);
>  
>  #ifndef __HAVE_ARCH_MEMMOVE
>  /**
> -- 
> 2.30.2
> 
> 
> 

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