1 files changed, 94 insertions, 0 deletions
diff --git a/src/vppinfra/string.c b/src/vppinfra/string.c
new file mode 100644
index 00000000000..ba21e7b3490
--- /dev/null
+++ b/src/vppinfra/string.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/*
+  Copyright (c) 2006 Eliot Dresselhaus
+
+  Permission is hereby granted, free of charge, to any person obtaining
+  a copy of this software and associated documentation files (the
+  "Software"), to deal in the Software without restriction, including
+  without limitation the rights to use, copy, modify, merge, publish,
+  distribute, sublicense, and/or sell copies of the Software, and to
+  permit persons to whom the Software is furnished to do so, subject to
+  the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#include <vppinfra/string.h>
+#include <vppinfra/error.h>
+
+/* Exchanges source and destination. */
+void
+clib_memswap (void *_a, void *_b, uword bytes)
+{
+  uword pa = pointer_to_uword (_a);
+  uword pb = pointer_to_uword (_b);
+
+#define _(TYPE)					\
+  if (0 == ((pa | pb) & (sizeof (TYPE) - 1)))	\
+    {						\
+      TYPE * a = uword_to_pointer (pa, TYPE *);	\
+      TYPE * b = uword_to_pointer (pb, TYPE *);	\
+						\
+      while (bytes >= 2*sizeof (TYPE))		\
+	{					\
+	  TYPE a0, a1, b0, b1;			\
+	  bytes -= 2*sizeof (TYPE);		\
+	  a += 2;				\
+	  b += 2;				\
+	  a0 = a[-2]; a1 = a[-1];		\
+	  b0 = b[-2]; b1 = b[-1];		\
+	  a[-2] = b0; a[-1] = b1;		\
+	  b[-2] = a0; b[-1] = a1;		\
+	}					\
+      pa = pointer_to_uword (a);		\
+      pb = pointer_to_uword (b);		\
+    }
+
+  if (BITS (uword) == BITS (u64))
+    _(u64);
+  _(u32);
+  _(u16);
+  _(u8);
+
+#undef _
+
+  ASSERT (bytes < 2);
+  if (bytes)
+    {
+      u8 *a = uword_to_pointer (pa, u8 *);
+      u8 *b = uword_to_pointer (pb, u8 *);
+      u8 a0 = a[0], b0 = b[0];
+      a[0] = b0;
+      b[0] = a0;
+    }
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */