Re: [PATCH v2 01/41] lib: Add a way to find the postiion of a trailing number

[Heinrich Schuchardt]

On 10/24/21 01:25, 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 <s...@chromium.org>
---

(no changes since v1)

  include/vsprintf.h | 18 ++++++++++++++++++
  lib/strto.c        | 14 ++++++++++++--
  2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/include/vsprintf.h b/include/vsprintf.h
index b4746301462..8230e7a5126 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() - extract a 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).

Please, provide a test with as string like 'abc123def456'.

+ *
+ * @str:       String to exxamine
+ * @end:       Pointer to end of string to examine, or NULL to use the
+ *             whole string
+ * @lenp:      If non-NULL, this is set to the number of characters before the
+ *     number starts, e.g. for "mmc0" this would be 3; if no trailing number is
+ *     found, it is set to the length of the whole string
+ * @return training number if found, else -1
+ */
+long trailing_strtoln_len(const char *str, const char *end, int *lenp);

Usage in a caller would be easier if you would return a pointer to the 
first digit instead of a length.

Best regards

Heinrich

+
  /**
   * panic() - Print a message and reset/hang
   *
diff --git a/lib/strto.c b/lib/strto.c
index 7bba1e3e549..13ae22a87a1 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_len(const char *str, const char *end, int *lenp)
  {
        const char *p;
  
@@ -191,14 +191,24 @@ long trailing_strtoln(const char *str, const char *end)
                end = str + strlen(str);
        if (isdigit(end[-1])) {
                for (p = end - 1; p > str; p--) {
-                       if (!isdigit(*p))
+                       if (!isdigit(*p)) {
+                               if (lenp)
+                                       *lenp = p - str + 1;
                                return dectoul(p + 1, NULL);
+                       }
                }
        }
+       if (lenp)
+               *lenp = end - str;
  
  	return -1;
  }
  
+long trailing_strtoln(const char *str, const char *end)
+{
+       return trailing_strtoln_len(str, end, NULL);
+}
+
  long trailing_strtol(const char *str)
  {
        return trailing_strtoln(str, NULL);