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authorOndřej Bílka <neleai@seznam.cz>2014-12-19 23:09:40 +0100
committerOndřej Bílka <neleai@seznam.cz>2014-12-19 23:09:40 +0100
commit3eb38795dbbbd8160012050de4dfef200a21f2bf (patch)
tree3baf6d14d95902ed16f5045085b1d41fc9e74051
parent0d4ba8be9cd4cebcc2418c72c22a12fc9baf2c85 (diff)
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Simplify strncat.
We rewrite strncat to use strnlen and malloc calls which simplifies code an is faster as these functions are better optimized than original code.
-rw-r--r--ChangeLog4
-rw-r--r--string/strncat.c47
2 files changed, 7 insertions, 44 deletions
diff --git a/ChangeLog b/ChangeLog
index 3cef094bc5..4c8bcb418f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2014-12-19 Ondřej Bílka <neleai@seznam.cz>
+
+ * string/strncat.c (STRNCAT): Simplify implementation.
+
2014-12-19 David S. Miller <davem@davemloft.net>
* sysdeps/sparc/sparc32/soft-fp/q_neg.c (_Q_neg): Use a union to
diff --git a/string/strncat.c b/string/strncat.c
index 6d29114d38..0de9a01fde 100644
--- a/string/strncat.c
+++ b/string/strncat.c
@@ -17,10 +17,6 @@
#include <string.h>
-#ifdef _LIBC
-# include <memcopy.h>
-#endif
-
#ifndef STRNCAT
# undef strncat
# define STRNCAT strncat
@@ -29,52 +25,15 @@
char *
STRNCAT (char *s1, const char *s2, size_t n)
{
- char c;
char *s = s1;
/* Find the end of S1. */
s1 += strlen (s1);
- /* Make S1 point before next character, so we can increment
- it while memory is read (wins on pipelined cpus). */
- s1 -= 1;
-
- if (n >= 4)
- {
- size_t n4 = n >> 2;
- do
- {
- c = *s2++;
- *++s1 = c;
- if (c == '\0')
- return s;
- c = *s2++;
- *++s1 = c;
- if (c == '\0')
- return s;
- c = *s2++;
- *++s1 = c;
- if (c == '\0')
- return s;
- c = *s2++;
- *++s1 = c;
- if (c == '\0')
- return s;
- } while (--n4 > 0);
- n &= 3;
- }
-
- while (n > 0)
- {
- c = *s2++;
- *++s1 = c;
- if (c == '\0')
- return s;
- n--;
- }
+ size_t ss = __strnlen (s2, n);
- if (c != '\0')
- *++s1 = '\0';
+ s1[ss] = '\0';
+ memcpy (s1, s2, ss);
return s;
}