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author2012-12-27 Bruno Haible <bruno@clisp.org>2012-12-27 22:37:39 +0100
committerAndreas Jaeger <aj@suse.de>2012-12-27 22:37:39 +0100
commit7fffbdfff7d39cec0783e5b9381fa4093484c235 (patch)
treefba3a354f4eafa41e26f844db6dfa6c18476a9b1 /string/xpg-strerror.c
parent9c7595bda2c37b31e82dab424bfd3015664b176d (diff)
downloadglibc-7fffbdfff7d39cec0783e5b9381fa4093484c235.tar.gz
BZ#14317: Optimze __xpg_strerror_r
[BZ #14317] * string/xpg-strerror.c (__xpg_strerror_r): Optimize, call strlen only if needed.
Diffstat (limited to 'string/xpg-strerror.c')
-rw-r--r--string/xpg-strerror.c24
1 files changed, 15 insertions, 9 deletions
diff --git a/string/xpg-strerror.c b/string/xpg-strerror.c
index 7e46b33183..73600fb6a2 100644
--- a/string/xpg-strerror.c
+++ b/string/xpg-strerror.c
@@ -1,5 +1,4 @@
-/* Copyright (C) 1991, 1993, 1995-1998, 2000, 2002, 2004, 2010, 2011
- Free Software Foundation, Inc.
+/* Copyright (C) 1991-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -28,20 +27,27 @@ int
__xpg_strerror_r (int errnum, char *buf, size_t buflen)
{
const char *estr = __strerror_r (errnum, buf, buflen);
- size_t estrlen = strlen (estr);
+ /* We know that __strerror_r returns buf (with a dynamically computed
+ string) if errnum is invalid, otherwise it returns a string whose
+ storage has indefinite extent. */
if (estr == buf)
{
assert (errnum < 0 || errnum >= _sys_nerr_internal
|| _sys_errlist_internal[errnum] == NULL);
return EINVAL;
}
- assert (errnum >= 0 && errnum < _sys_nerr_internal
- && _sys_errlist_internal[errnum] != NULL);
+ else
+ {
+ assert (errnum >= 0 && errnum < _sys_nerr_internal
+ && _sys_errlist_internal[errnum] != NULL);
+
+ size_t estrlen = strlen (estr);
- /* Terminate the string in any case. */
- if (buflen > 0)
- *((char *) __mempcpy (buf, estr, MIN (buflen - 1, estrlen))) = '\0';
+ /* Terminate the string in any case. */
+ if (buflen > 0)
+ *((char *) __mempcpy (buf, estr, MIN (buflen - 1, estrlen))) = '\0';
- return buflen <= estrlen ? ERANGE : 0;
+ return buflen <= estrlen ? ERANGE : 0;
+ }
}