common: Add gnupg_memstr to replace static versions.

* common/stringhelp.c (gnupg_memstr): New.
* common/mbox-util.c (my_memstr): Remove.
(is_valid_mailbox_mem): Use gnupg_memstr.
* common/recsel.c (my_memstr): Remove.
(recsel_select): Use gnupg_memstr.

1 files changed, 29 insertions, 0 deletions

diff --git a/common/stringhelp.c b/common/stringhelp.c
index 1049c78e2..5407653de 100644
--- a/common/stringhelp.c
+++ b/common/stringhelp.c
@@ -161,6 +161,35 @@ ascii_memistr ( const void *buffer, size_t buflen, const char *sub )
 }
 
 
+/* This is a case-sensitive version of our memistr.  I wonder why no
+ * standard function memstr exists but we better do not use the name
+ * memstr to avoid future conflicts.
+ */
+const char *
+gnupg_memstr (const void *buffer, size_t buflen, const char *sub)
+{
+  const unsigned char *buf = buffer;
+  const unsigned char *t = (const unsigned char *)buf;
+  const unsigned char *s = (const unsigned char *)sub;
+  size_t n = buflen;
+
+  for ( ; n ; t++, n-- )
+    {
+      if (*t == *s)
+        {
+          for (buf = t++, buflen = n--, s++; n && *t ==*s; t++, s++, n--)
+            ;
+          if (!*s)
+            return (const char*)buf;
+          t = (const unsigned char *)buf;
+          s = (const unsigned char *)sub ;
+          n = buflen;
+	}
+    }
+  return NULL;
+}
+
+
 /* This function is similar to strncpy().  However it won't copy more
  * than N - 1 characters and makes sure that a '\0' is appended. With
  * N given as 0, nothing will happen.  With DEST given as NULL, memory