Re: [PATCH] Fix the spu specific strxfrm to match generic newlib and glibc

[Joel Schopp <jschopp at austin dot ibm dot com>]

This bug was originally caused by me and my misreading of the standard (to be fair 
the language is as clear as mud).  This patch makes the behavior match what the 
standard intended, which is also the behavior of glibc.  For correctness that should 
probably be my name in the changelog as I originally authored this patch.

-Joel

Patrick Mansfield wrote:
> Jeff - can you please apply this fix?
>
> Fix the spu specific strxfrm so that when the length of the src string is
> greater than or equal to the passed in argument n we still copy over n
> bytes.
>
> This matches the current glibc and the generic newlib strxfrm behaviour.
>
> newlib ChangeLog:
>
> 2007-04-06  Patrick Mansfield <patmans@us.ibm.com>
>   
> 	* libc/machine/spu/strxfrm.c: Fix strxfrm so we still copy data
> 	even if the passed in length n is shorter than the source string.
> 	This matches both the non-spu specific and the glibc strxfrm
> 	behaviour.
>
> Index: my-base-quilt/newlib/libc/machine/spu/strxfrm.c
> ===================================================================
> --- my-base-quilt.orig/newlib/libc/machine/spu/strxfrm.c
> +++ my-base-quilt/newlib/libc/machine/spu/strxfrm.c
> @@ -34,6 +34,7 @@
>  #include <stddef.h>
>  #include <string.h>
>  
> +#define min(a, b)  (a) < (b) ? (a) : (b)
>  
>  /* The strxfrm() function transforms the src string into a form such that
>   * the result of strcmp() on two strings that have been transformed with
> @@ -54,13 +55,7 @@ size_t strxfrm(char * __restrict__ dest,
>    size_t len;
>  
>    len = strlen(src);
> +  (void)memcpy((void *)dest, (void *)src, min(n,len + 1));
>  
> -  /* Since the destination is indeterminant if n is less than of equal
> -   * to the string length, we skip performing the copy (altogether) in
> -   * this case.
> -   */
> -  if (n > len) {
> -    (void)memcpy((void *)dest, (void *)src, n);
> -  }
> -  return (len);
> +  return len;
>  }