[PATCH 1/1] string: Add stpecpy(3)

[Alejandro Colomar]

On 12/23/22 18:03, Alejandro Colomar wrote:
> alx@asus5775:~/src/alx/libstp/src$ grepc -tfd stpecpy
> ./stp/stpe/stpecpy.c:15:
> char *stp_nullable
> stpecpy(char *stp_nullable dst, char end[0], const char *restrict src)
> {
>      char  *stp_nullable p;
> 
>      if (dst == end)
>          return end;
>      if (stp_unlikely(dst == NULL))  // Allow chaining with stpeprintf().
>          return NULL;

Oh, and the two branches above can be optimized into a branch that returns dst. 
I wrote them expanded, for added readability, and allow the compiler reorganize 
it however it pleases.  So, in reality, there are 2 actual branches, plus one 
inside memccpy(3).

>      if (dst > end)
>          stp_unreachable();
> 
>      p = memccpy(dst, src, '\0', end - dst);
>      if (p != NULL)
>          return p - 1;
> 
>      /* Truncation detected. */
>      end[-1] = '\0';
>      return end;
> }
> 
> alx@asus5775:~/src/gnu/glibc$ grepc -tfd __memccpy
> ./string/memccpy.c:30:
> void *
> __memccpy (void *dest, const void *src, int c, size_t n)
> {
>    void *p = memchr (src, c, n);
> 
>    if (p != NULL)
>      return __mempcpy (dest, src, p - src + 1);
> 
>    memcpy (dest, src, n);
>    return NULL;
> }
> 

-- 
<http://www.alejandro-colomar.es/>
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