[incubator-nuttx] branch master updated: libc/string: simplify strrchr

[xi...@apache.org]

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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git


The following commit(s) were added to refs/heads/master by this push:
     new a17bfec43d libc/string: simplify strrchr
a17bfec43d is described below

commit a17bfec43df0f3d509dba5be74d19c790a7e76e4
Author: Juha Niskanen <ju...@haltian.com>
AuthorDate: Tue May 10 15:02:40 2022 +0300

    libc/string: simplify strrchr
    
    Do not call strlen() here. Old implementation iterated
    over string twice, if searched for position was at the
    beginning. This commit changes strrchr() to scan string
    only once, regardless of input.
    
    Signed-off-by: Juha Niskanen <ju...@haltian.com>
---
 libs/libc/string/lib_strchrnul.c |  2 +-
 libs/libc/string/lib_strrchr.c   | 11 ++++++-----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/libs/libc/string/lib_strchrnul.c b/libs/libc/string/lib_strchrnul.c
index ab15fb9600..d338efcc58 100644
--- a/libs/libc/string/lib_strchrnul.c
+++ b/libs/libc/string/lib_strchrnul.c
@@ -39,7 +39,7 @@
  *   considered to be part of the string.
  *
  * Returned Value:
- *   Upon completion, strchrnull() returns a pointer to the byte, or a
+ *   Upon completion, strchrnul() returns a pointer to the byte, or a
  *   pointer to null if the byte was not found.
  *
  ****************************************************************************/
diff --git a/libs/libc/string/lib_strrchr.c b/libs/libc/string/lib_strrchr.c
index 2a04b06c71..6c6b5d961e 100644
--- a/libs/libc/string/lib_strrchr.c
+++ b/libs/libc/string/lib_strrchr.c
@@ -37,15 +37,16 @@
 #undef strrchr /* See mm/README.txt */
 FAR char *strrchr(FAR const char *s, int c)
 {
-  FAR const char *p = &s[strlen(s)];
+  FAR const char *r = NULL;
 
-  for (; p >= s; p--)
+  do
     {
-      if (*p == c)
+      if (*s == c)
         {
-          return (FAR char *)p;
+          r = s;
         }
     }
+  while (*s++ != '\0');
 
-  return NULL;
+  return (FAR char *)r;
 }