1 files changed, 109 insertions, 0 deletions
diff --git a/src/lib/libast/string/swapmem.c b/src/lib/libast/string/swapmem.c
new file mode 100644
index 0000000..7a96bf0
--- /dev/null
+++ b/src/lib/libast/string/swapmem.c
@@ -0,0 +1,109 @@
+/***********************************************************************
+*                                                                      *
+*               This software is part of the ast package               *
+*          Copyright (c) 1985-2011 AT&T Intellectual Property          *
+*                      and is licensed under the                       *
+*                 Eclipse Public License, Version 1.0                  *
+*                    by AT&T Intellectual Property                     *
+*                                                                      *
+*                A copy of the License is available at                 *
+*          http://www.eclipse.org/org/documents/epl-v10.html           *
+*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
+*                                                                      *
+*              Information and Software Systems Research               *
+*                            AT&T Research                             *
+*                           Florham Park NJ                            *
+*                                                                      *
+*                 Glenn Fowler <gsf@research.att.com>                  *
+*                  David Korn <dgk@research.att.com>                   *
+*                   Phong Vo <kpv@research.att.com>                    *
+*                                                                      *
+***********************************************************************/
+#pragma prototyped
+/*
+ * Glenn Fowler
+ * AT&T Research
+ *
+ * internal representation conversion support
+ */
+
+#include <ast.h>
+#include <swap.h>
+
+/*
+ * swap n bytes according to op
+ * from==to is ok
+ */
+
+void*
+swapmem(int op, const void* from, void* to, register size_t n)
+{
+	register char*	f = (char*)from;
+	register char*	t = (char*)to;
+	register int	c;
+
+	switch (op & (n - 1))
+	{
+	case 0:
+		if (t != f)
+			memcpy(t, f, n);
+		break;
+	case 1:
+		for (n >>= 1; n--; f += 2, t += 2)
+		{
+			c = f[0]; t[0] = f[1]; t[1] = c;
+		}
+		break;
+	case 2:
+		for (n >>= 2; n--; f += 4, t += 4)
+		{
+			c = f[0]; t[0] = f[2]; t[2] = c;
+			c = f[1]; t[1] = f[3]; t[3] = c;
+		}
+		break;
+	case 3:
+		for (n >>= 2; n--; f += 4, t += 4)
+		{
+			c = f[0]; t[0] = f[3]; t[3] = c;
+			c = f[1]; t[1] = f[2]; t[2] = c;
+		}
+		break;
+	case 4:
+		for (n >>= 3; n--; f += 8, t += 8)
+		{
+			c = f[0]; t[0] = f[4]; t[4] = c;
+			c = f[1]; t[1] = f[5]; t[5] = c;
+			c = f[2]; t[2] = f[6]; t[6] = c;
+			c = f[3]; t[3] = f[7]; t[7] = c;
+		}
+		break;
+	case 5:
+		for (n >>= 3; n--; f += 8, t += 8)
+		{
+			c = f[0]; t[0] = f[5]; t[5] = c;
+			c = f[1]; t[1] = f[4]; t[4] = c;
+			c = f[2]; t[2] = f[7]; t[7] = c;
+			c = f[3]; t[3] = f[6]; t[6] = c;
+		}
+		break;
+	case 6:
+		for (n >>= 3; n--; f += 8, t += 8)
+		{
+			c = f[0]; t[0] = f[6]; t[6] = c;
+			c = f[1]; t[1] = f[7]; t[7] = c;
+			c = f[2]; t[2] = f[4]; t[4] = c;
+			c = f[3]; t[3] = f[5]; t[5] = c;
+		}
+		break;
+	case 7:
+		for (n >>= 3; n--; f += 8, t += 8)
+		{
+			c = f[0]; t[0] = f[7]; t[7] = c;
+			c = f[1]; t[1] = f[6]; t[6] = c;
+			c = f[2]; t[2] = f[5]; t[5] = c;
+			c = f[3]; t[3] = f[4]; t[4] = c;
+		}
+		break;
+	}
+	return to;
+}