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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /sysdeps/generic/strncat.c
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initial import
Diffstat (limited to 'sysdeps/generic/strncat.c')
-rw-r--r--sysdeps/generic/strncat.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/sysdeps/generic/strncat.c b/sysdeps/generic/strncat.c
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+++ b/sysdeps/generic/strncat.c
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+/* Copyright (C) 1991 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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <string.h>
+#include <memcopy.h>
+
+char *
+DEFUN(strncat, (s1, s2, n), char *s1 AND CONST char *s2 AND 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;
+}