On Sat, Nov 24, 2018 at 02:47:54PM -0600, Rob Herring wrote:
> Add variadic and va_list functions, xa{v}sprintf, which appends a
> formatted string to an existing string and re-allocate the string buffer
> if necessary. xasprintf becomes just a special case of xasprintf_append
> with a NULL starting string.
>
> Rather than looping to get a big enough buffer, simply the implementation
> by assuming we have a C99 compliant vsnprintf implementation to return the
> necessary size. A side effect is glibc 2.0 support is dropped which seems
> unnecessary.
>
> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
Series applied, thanks.
> ---
> util.c | 60 ++++++++++++++++++++++++++++++++++++++--------------------
> util.h | 2 ++
> 2 files changed, 41 insertions(+), 21 deletions(-)
>
> diff --git a/util.c b/util.c
> index a69b7a13463d..9c6fb5f286ae 100644
> --- a/util.c
> +++ b/util.c
> @@ -46,36 +46,54 @@ char *xstrdup(const char *s)
> return d;
> }
>
> -/* based in part from (3) vsnprintf */
> -int xasprintf(char **strp, const char *fmt, ...)
> +int xavsprintf_append(char **strp, const char *fmt, va_list ap)
> {
> - int n, size = 128; /* start with 128 bytes */
> + int n, size = 0; /* start with 128 bytes */
> char *p;
> - va_list ap;
> + va_list ap_copy;
>
> - /* initial pointer is NULL making the fist realloc to be malloc */
> - p = NULL;
> - while (1) {
> - p = xrealloc(p, size);
> + p = *strp;
> + if (p)
> + size = strlen(p);
>
> - /* Try to print in the allocated space. */
> - va_start(ap, fmt);
> - n = vsnprintf(p, size, fmt, ap);
> - va_end(ap);
> + va_copy(ap_copy, ap);
> + n = vsnprintf(NULL, 0, fmt, ap_copy) + 1;
> + va_end(ap_copy);
> +
> + p = xrealloc(p, size + n);
> +
> + n = vsnprintf(p + size, n, fmt, ap);
>
> - /* If that worked, return the string. */
> - if (n > -1 && n < size)
> - break;
> - /* Else try again with more space. */
> - if (n > -1) /* glibc 2.1 */
> - size = n + 1; /* precisely what is needed */
> - else /* glibc 2.0 */
> - size *= 2; /* twice the old size */
> - }
> *strp = p;
> return strlen(p);
> }
>
> +int xasprintf_append(char **strp, const char *fmt, ...)
> +{
> + int n;
> + va_list ap;
> +
> + va_start(ap, fmt);
> + n = xavsprintf_append(strp, fmt, ap);
> + va_end(ap);
> +
> + return n;
> +}
> +
> +int xasprintf(char **strp, const char *fmt, ...)
> +{
> + int n;
> + va_list ap;
> +
> + *strp = NULL;
> +
> + va_start(ap, fmt);
> + n = xavsprintf_append(strp, fmt, ap);
> + va_end(ap);
> +
> + return n;
> +}
> +
> char *join_path(const char *path, const char *name)
> {
> int lenp = strlen(path);
> diff --git a/util.h b/util.h
> index f6cea8274174..7658781a6200 100644
> --- a/util.h
> +++ b/util.h
> @@ -72,6 +72,8 @@ static inline void *xrealloc(void *p, size_t len)
> extern char *xstrdup(const char *s);
>
> extern int PRINTF(2, 3) xasprintf(char **strp, const char *fmt, ...);
> +extern int PRINTF(2, 3) xasprintf_append(char **strp, const char *fmt, ...);
> +extern int xavsprintf_append(char **strp, const char *fmt, va_list ap);
> extern char *join_path(const char *path, const char *name);
>
> /**
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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