[PATCH v4 05/33] lib: Add a way to find the postiion of a trailing number

Simon Glass
2022-03-06T12:51:57Z

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@chromium.org>
---

Changes in v4:
- Use new Return style in function comments

Changes in v3:
- Add some tests, including one for 'abc123def456'
- Change the function to return a pointer to the first digit

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 5172ceedec..e006af200f 100644
--- a/include/vsprintf.h
+++ b/include/vsprintf.h
@@ -121,6 +121,24 @@ 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 examine
+ * @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
+ */
+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 b1d803a77d..6462d4fddf 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 058b359437..5a844347c2 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);
--
2.35.1.616.g0bdcbb4464-goog