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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 /string
parent0d4ba8be9cd4cebcc2418c72c22a12fc9baf2c85 (diff)
downloadglibc-3eb38795dbbbd8160012050de4dfef200a21f2bf.tar.gz
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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.
Diffstat (limited to 'string')
-rw-r--r--string/strncat.c47
1 files changed, 3 insertions, 44 deletions
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;
 }