* nettle-write.h: New file.

* write-be32.c (nettle_write_be32): New file, new function.

Rev: nettle/nettle-write.h:1.1
Rev: nettle/write-be32.c:1.1

nettle-write.h

+/* nettle-write.h
+ *
+ * Prototypes for some internal functions to write out word-sized data
+ * to byte arrays. */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2010 Niels Möller
+ *  
+ * The nettle library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ *
+ * The nettle 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 Lesser General Public
+ * License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the nettle library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#ifndef NETTLE_WRITE_H_INCLUDED
+#define NETTLE_WRITE_H_INCLUDED
+
+#include "nettle-stdint.h"
+
+/* Write the word array at SRC to the byte array at DST, using little
+   endian (le) or big endian (be) byte order, and truncating the
+   result to LENGTH bytes. */
+void
+_nettle_write_be32(unsigned length, uint8_t *dst,
+		   uint32_t *src);
+void
+_nettle_write_le32(unsigned length, uint8_t *dst,
+		   uint32_t *src);
+void
+_nettle_write_be64(unsigned length, uint8_t *dst,
+		   uint64_t *src);
+
+#endif /* NETTLE_WRITE_H_INCLUDED */

write-be32.c

+/* write-be32.c */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2001 Niels Mller
+ *  
+ * The nettle library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ *
+ * The nettle 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 Lesser General Public
+ * License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the nettle library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdlib.h>
+
+#include "nettle-write.h"
+
+#include "macros.h"
+
+void
+_nettle_write_be32(unsigned length, uint8_t *dst,
+		   uint32_t *src)
+{
+  unsigned i;
+  unsigned words;
+  unsigned leftover;
+  
+  words = length / 4;
+  leftover = length % 4;
+
+  for (i = 0; i < words; i++, dst += 4)
+    WRITE_UINT32(dst, src[i]);
+
+  if (leftover)
+    {
+      uint32_t word;
+      unsigned j = leftover;
+      
+      word = src[i];
+      
+      switch (leftover)
+	{
+	default:
+	  abort();
+	case 3:
+	  dst[--j] = (word >> 8) & 0xff;
+	  /* Fall through */
+	case 2:
+	  dst[--j] = (word >> 16) & 0xff;
+	  /* Fall through */
+	case 1:
+	  dst[--j] = (word >> 24) & 0xff;
+	}
+    }
+}