Re: [Patch, Newlib-nano]Improve printf to support non nul-terminated string

[Corinna Vinschen <vinschen at redhat dot com>]

[Please don't CC me.  I'm reading the mailing list anyway.  Thanks]

On Nov  6 13:53, Terry Guo wrote:
> Thanks. Here is updated patch. Is this one OK?

It's fine from my POV.  Bin?


Corinna

> 
> BR,
> Terry

> diff --git a/newlib/libc/stdio/nano-vfprintf_i.c b/newlib/libc/stdio/nano-vfprintf_i.c
> index b1b0d1d..b75a142 100644
> --- a/newlib/libc/stdio/nano-vfprintf_i.c
> +++ b/newlib/libc/stdio/nano-vfprintf_i.c
> @@ -211,15 +211,15 @@ number:
>      case 's':
>        cp = GET_ARG (N, *ap, char_ptr_t);
>        /* Precision gives the maximum number of chars to be written from a
> -	 string, and take prec == -1 into consideration.  */
> -      if ((u_int)(pdata->size = strlen (cp)) > (u_int)(pdata->prec))
> -	pdata->size = pdata->prec;
> -      /* Below code is kept for reading.  The check is redundant because
> -	 pdata->prec will be set to pdata->size if it is -1 previously.  */
> -#if 0
> -      if (pdata->prec > pdata->size)
> -#endif
> -      pdata->prec = pdata->size;
> +	 string, and take prec == -1 into consideration.
> +	 Use normal Newlib approach here to support case where cp is not
> +	 nul-terminated.  */
> +      char *p = memchr (cp, 0, pdata->prec);
> +
> +      if (p != NULL)
> +	pdata->prec = p - cp;
> +
> +      pdata->size = pdata->prec;
>        goto non_number_nosign;
>      default:
>        /* "%?" prints ?, unless ? is NUL.  */
> diff --git a/newlib/testsuite/newlib.stdio/nulprintf.c b/newlib/testsuite/newlib.stdio/nulprintf.c
> new file mode 100644
> index 0000000..5e4131b
> --- /dev/null
> +++ b/newlib/testsuite/newlib.stdio/nulprintf.c
> @@ -0,0 +1,17 @@
> +/*
> + * Copyright (C) 2014 by ARM Ltd. All rights reserved.
> + *
> + * Permission to use, copy, modify, and distribute this software
> + * is freely granted, provided that this notice is preserved.
> + */
> +
> +#include <stdio.h>
> +#include "check.h"
> +
> +const char m[8] = {'M','M','M','M','M','M','M','M'};
> +
> +int main()
> +{
> +  printf ("%.*s\n", 8, m);
> +  exit (0);
> +}


-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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