1 files changed, 61 insertions, 0 deletions

diff --git a/src/lib/libc/string/swab.c b/src/lib/libc/string/swab.c
new file mode 100644
index 0000000000..b74db7e62a
--- /dev/null
+++ b/src/lib/libc/string/swab.c
@@ -0,0 +1,61 @@
+/*      $OpenBSD: swab.c,v 1.8 2008/03/15 21:54:09 ray Exp $ */
+/*
+ * Copyright (c) 1988 Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Jeffrey Mogul.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <unistd.h>
+
+void
+swab(const void *from, void *to, size_t len)
+{
+        size_t n;
+        char *fp, *tp;
+        char temp;
+
+        n = (len / 2) + 1;
+        fp = (char *)from;
+        tp = (char *)to;
+#define STEP do {       \
+        temp = *fp++;   \
+        *tp++ = *fp++;  \
+        *tp++ = temp;   \
+} while (0)
+        /* round to multiple of 8 */
+        while ((--n) & 07)
+                STEP;
+        n >>= 3;
+        if (n == 0)
+                return;
+        while (n-- != 0) {
+                STEP; STEP; STEP; STEP;
+                STEP; STEP; STEP; STEP;
+        }
+}