[PATCH v3 04/31] lib: Add a way to find the postiion of a trailing number

[Heinrich Schuchardt]

On 1/19/22 02:42, Simon Glass wrote:
> At present it is not possible to find out which part of the string is the
> number part and which is before it. Add a new variant which provides this
> feature, so we can separate the two in the caller.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> Changes in v3:
> - Change the function to return a pointer to the first digit
> - Add some tests, including one for 'abc123def456'
>
>   include/vsprintf.h | 18 ++++++++++++++++++
>   lib/strto.c        | 14 ++++++++++++--
>   test/str_ut.c      | 13 ++++++++++++-
>   3 files changed, 42 insertions(+), 3 deletions(-)
>
> diff --git a/include/vsprintf.h b/include/vsprintf.h
> index 01d2248e04d..ce7a7aaa1cc 100644
> --- a/include/vsprintf.h
> +++ b/include/vsprintf.h
> @@ -118,6 +118,24 @@ long trailing_strtol(const char *str);
>    */
>   long trailing_strtoln(const char *str, const char *end);
>
> +/**
> + * trailing_strtoln_end() - extract trailing integer from a fixed-length string
> + *
> + * Given a fixed-length string this finds a trailing number on the string
> + * and returns it. For example, "abc123" would return 123. Only the
> + * characters between @str and @end - 1 are examined. If @end is NULL, it is
> + * set to str + strlen(str).
> + *
> + * @str:	String to exxamine
> + * @end:	Pointer to end of string to examine, or NULL to use the
> + *		whole string
> + * @endp:	If non-NULL, this is set to point to the character where the
> + *	number starts, e.g. for "mmc0" this would be point to the '0'; if no
> + *	trailing number is found, it is set to the end of the string
> + * @return training number if found, else -1

Return:

https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html#function-documentation

Best regards

Heinrich

> + */
> +long trailing_strtoln_end(const char *str, const char *end, char const **endp);
> +
>   /**
>    * panic() - Print a message and reset/hang
>    *
> diff --git a/lib/strto.c b/lib/strto.c
> index 58fc10ecaea..72cfef660fc 100644
> --- a/lib/strto.c
> +++ b/lib/strto.c
> @@ -183,7 +183,7 @@ long long simple_strtoll(const char *cp, char **endp, unsigned int base)
>   	return simple_strtoull(cp, endp, base);
>   }
>
> -long trailing_strtoln(const char *str, const char *end)
> +long trailing_strtoln_end(const char *str, const char *end, char const **endp)
>   {
>   	const char *p;
>
> @@ -192,14 +192,24 @@ long trailing_strtoln(const char *str, const char *end)
>   	p = end - 1;
>   	if (p > str && isdigit(*p)) {
>   		do {
> -			if (!isdigit(p[-1]))
> +			if (!isdigit(p[-1])) {
> +				if (endp)
> +					*endp = p;
>   				return dectoul(p, NULL);
> +			}
>   		} while (--p > str);
>   	}
> +	if (endp)
> +		*endp = end;
>
>   	return -1;
>   }
>
> +long trailing_strtoln(const char *str, const char *end)
> +{
> +	return trailing_strtoln_end(str, end, NULL);
> +}
> +
>   long trailing_strtol(const char *str)
>   {
>   	return trailing_strtoln(str, NULL);
> diff --git a/test/str_ut.c b/test/str_ut.c
> index 058b3594379..5a844347c2b 100644
> --- a/test/str_ut.c
> +++ b/test/str_ut.c
> @@ -244,7 +244,9 @@ STR_TEST(str_xtoa, 0);
>
>   static int str_trailing(struct unit_test_state *uts)
>   {
> -	char str1[] = "abc123def";
> +	const char str1[] = "abc123def";
> +	const char str2[] = "abc123def456";
> +	const char *end;
>
>   	ut_asserteq(-1, trailing_strtol(""));
>   	ut_asserteq(-1, trailing_strtol("123"));
> @@ -259,6 +261,15 @@ static int str_trailing(struct unit_test_state *uts)
>
>   	ut_asserteq(3, trailing_strtol("a3"));
>
> +	ut_asserteq(123, trailing_strtoln_end(str1, str1 + 6, &end));
> +	ut_asserteq(3, end - str1);
> +
> +	ut_asserteq(-1, trailing_strtoln_end(str1, str1 + 7, &end));
> +	ut_asserteq(7, end - str1);
> +
> +	ut_asserteq(456, trailing_strtoln_end(str2, NULL, &end));
> +	ut_asserteq(9, end - str2);
> +
>   	return 0;
>   }
>   STR_TEST(str_trailing, 0);