Re: [PATCH] eal: add helper to skip whitespaces

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, Feb 14, 2024 at 01:12:19PM +0100, David Marchand wrote:
> Reduce code duplication by providing a simple inline helper.
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>  app/graph/utils.c                          | 13 ++------
>  app/test-eventdev/parser.c                 | 14 ++++-----
>  app/test-eventdev/parser.h                 |  8 -----
>  app/test-mldev/parser.c                    | 17 ++++++-----
>  app/test-mldev/parser.h                    |  8 -----
>  app/test-pmd/cmdline_tm.c                  | 13 ++------
>  app/test/test_string_fns.c                 | 35 ++++++++++++++++++++++
>  examples/fips_validation/fips_validation.c | 16 +++-------
>  examples/ip_pipeline/parser.c              | 14 ++++-----
>  examples/ip_pipeline/parser.h              |  8 -----
>  examples/pipeline/cli.c                    | 13 ++------
>  lib/eal/include/rte_string_fns.h           | 27 +++++++++++++++++
>  12 files changed, 98 insertions(+), 88 deletions(-)
> 
> diff --git a/app/graph/utils.c b/app/graph/utils.c
> index c7b6ae83cf..1f5ee68273 100644
> --- a/app/graph/utils.c
> +++ b/app/graph/utils.c
> @@ -9,17 +9,10 @@
>  #include <string.h>
>  
>  #include <rte_common.h>
> +#include <rte_string_fns.h>
>  
>  #include "module_api.h"
>  
> -#define white_spaces_skip(pos)			\
> -({						\
> -	__typeof__(pos) _p = (pos);		\
> -	for ( ; isspace(*_p); _p++)		\
> -		;				\
> -	_p;					\
> -})
> -
>  static void
>  hex_string_to_uint64(uint64_t *dst, const char *hexs)
>  {
> @@ -47,7 +40,7 @@ parser_uint64_read(uint64_t *value, const char *p)
>  	char *next;
>  	uint64_t val;
>  
> -	p = white_spaces_skip(p);
> +	p = rte_str_skip_whitespaces(p);
>  	if (!isdigit(*p))
>  		return -EINVAL;
>  
> @@ -73,7 +66,7 @@ parser_uint64_read(uint64_t *value, const char *p)
>  		break;
>  	}
>  
> -	p = white_spaces_skip(p);
> +	p = rte_str_skip_whitespaces(p);

I like the idea of this. However, a question on naming. Do we want to make
it clear in the name that it only skips leading whitespace, and doesn't
e.g. trim whitespace off the end? How about:

rte_str_skip_leading_spaces()

It's longer, but I wonder if it's a bit clearer.

Also, might it be worthwhile providing an "rte_str_ltrim()" function along
with this, basically combining the skip_spaces call, with an memmove? Most
string handling in DPDK is not perf-sensitive and so a function with
similar name and behaviour to the python ltrim function may be appreciated
for its simplicity.

/Bruce