1 files changed, 71 insertions, 0 deletions
diff --git a/bswap-internal.h b/bswap-internal.h
new file mode 100644
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+++ b/bswap-internal.h
@@ -0,0 +1,71 @@
+/* bswap-internal.h
+
+   Copyright (C) 2022 Niels Möller
+
+   This file is part of GNU Nettle.
+
+   GNU Nettle is free software: you can redistribute it and/or
+   modify it under the terms of either:
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at your
+       option) any later version.
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at your
+       option) any later version.
+
+   or both in parallel, as here.
+
+   GNU Nettle 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
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef NETTLE_BSWAP_INTERNAL_H_INCLUDED
+#define NETTLE_BSWAP_INTERNAL_H_INCLUDED
+
+#include "nettle-types.h"
+
+/* Note that these definitions depend config.h, which should be
+   included first. */
+
+#if HAVE_BUILTIN_BSWAP64
+#define nettle_bswap64 __builtin_bswap64
+/* Assume bswap32 is also available. */
+#define nettle_bswap32 __builtin_bswap32
+#else
+static inline uint64_t
+nettle_bswap64 (uint64_t x)
+{
+  x = (x >> 32) | (x << 32);
+  x = ((x >> 16) & UINT64_C (0xffff0000ffff))
+    | ((x & UINT64_C (0xffff0000ffff)) << 16);
+  x = ((x >> 8) & UINT64_C (0xff00ff00ff00ff))
+    | ((x & UINT64_C (0xff00ff00ff00ff)) << 8);
+  return x;
+}
+
+static inline uint32_t
+nettle_bswap32 (uint32_t x)
+{
+  x = (x << 16) | (x >> 16);
+  x = ((x & 0x00FF00FF) << 8) | ((x >> 8) & 0x00FF00FF);
+  return x;
+}
+#endif
+
+#if WORDS_BIGENDIAN
+#define bswap64_if_le(x) (x)
+#else
+#define bswap64_if_le nettle_bswap64
+#endif
+
+#endif /* NETTLE_BSWAP_INTERNAL_H_INCLUDED */