1 files changed, 81 insertions, 0 deletions
diff --git a/libc/string/generic/strncat.c b/libc/string/generic/strncat.c
new file mode 100644
index 000000000..a3d283bf7
--- /dev/null
+++ b/libc/string/generic/strncat.c
@@ -0,0 +1,81 @@
+/* Copyright (C) 1991, 1997 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
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+
+#include "memcopy.h"
+
+#undef strncat
+
+char *
+strncat (s1, s2, n)
+     char *s1;
+     const char *s2;
+     size_t n;
+{
+  reg_char c;
+  char *s = s1;
+
+  /* Find the end of S1.  */
+  do
+    c = *s1++;
+  while (c != '\0');
+
+  /* Make S1 point before next character, so we can increment
+     it while memory is read (wins on pipelined cpus).  */
+  s1 -= 2;
+
+  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--;
+    }
+
+  if (c != '\0')
+    *++s1 = '\0';
+
+  return s;
+}