* base64-encode.c: New file. New supporting both encode-at-once

and streamed operation.

* base64-decode.c: New file.

Rev: src/nettle/base64-decode.c:1.1
Rev: src/nettle/base64-encode.c:1.1

1 files changed, 226 insertions, 0 deletions

diff --git a/base64-encode.c b/base64-encode.c
new file mode 100644
index 00000000..13b62526
--- /dev/null
+++ b/base64-encode.c
@@ -0,0 +1,226 @@
+/* base64-encode.c
+ *
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2002 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.
+ */
+
+#include "base64.h"
+
+#include <assert.h>
+#include <stdlib.h>
+
+
+static const uint8_t encode_table[64] =
+  "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+  "abcdefghijklmnopqrstuvwxyz"
+  "0123456789+/";
+
+#define ENCODE(x) (encode_table[0x3F & (x)])
+
+void
+base64_encode_raw(uint8_t *dst, unsigned length, const uint8_t *src)
+{
+  const uint8_t *in = src + length;;
+  uint8_t *out = dst + BASE64_ENCODE_RAW_LENGTH(length);
+
+  unsigned left_over = length % 3;
+
+  if (left_over)
+    {
+      in -= left_over;
+      *--out = '=';
+      switch(left_over)
+	{
+	case 1:
+	  *--out = '=';
+	  *--out = ENCODE(in[0] << 4);
+	  break;
+	  
+	case 2:
+	  *--out = ENCODE( in[1] << 2);
+	  *--out = ENCODE((in[0] << 4) | (in[1] >> 4));
+	  break;
+
+	default:
+	  abort();
+	}
+      *--out = ENCODE(in[0] >> 2);
+    }
+  
+  while (in > src)
+    {
+      in -= 3;
+      *--out = ENCODE( in[2]);
+      *--out = ENCODE((in[1] << 2) | (in[2] >> 6));
+      *--out = ENCODE((in[0] << 4) | (in[1] >> 4));
+      *--out = ENCODE( in[0] >> 2);      
+    }
+  assert(in == src);
+  assert(out == dst);
+}
+
+#if 0
+unsigned 
+base64_encode(uint8_t *dst,
+	      unsigned src_length,
+	      const uint8_t *src)
+{
+  unsigned dst_length = BASE64_ENCODE_RAW_LENGTH(src_length);
+  unsigned n = src_length / 3;
+  unsigned left_over  = src_length % 3;
+  unsigned done = 0;
+  
+  if (left_over)
+    {
+      const uint8_t *in = src + n * 3;
+      uint8_t *out = dst + dst_length;
+
+      switch(left_over)
+	{
+	case 1:
+	  *--out = '=';
+	  *--out = ENCODE(in[0] << 4);
+	  break;
+	  
+	case 2:
+	  *--out = ENCODE( in[1] << 2);
+	  *--out = ENCODE((in[0] << 4) | (in[1] >> 4));
+	  break;
+
+	default:
+	  abort();
+	}
+      *--out = ENCODE(in[0] >> 2);
+
+      done = 4;
+    }
+  base64_encode_raw(n, dst, src);
+  done += n * 4;
+
+  assert(done == dst_length);
+
+  return done;
+}
+#endif
+
+void
+base64_encode_group(uint8_t *dst, uint32_t group)
+{
+  *dst++ = ENCODE(group >> 18);
+  *dst++ = ENCODE(group >> 12);
+  *dst++ = ENCODE(group >> 6);
+  *dst++ = ENCODE(group);
+}
+
+void
+base64_encode_init(struct base64_encode_ctx *ctx)
+{
+  ctx->word = ctx->bits = 0;
+}
+
+/* Encodes a single byte. */
+unsigned
+base64_encode_single(struct base64_encode_ctx *ctx,
+		     uint8_t *dst,
+		     uint8_t src)
+{
+  unsigned done = 0;
+  unsigned word = ctx->word << 8 | src;
+  unsigned bits = ctx->bits + 8;
+  
+  while (bits >= 6)
+    {
+      bits -= 6;
+      dst[done++] = ENCODE(word >> bits);
+    }
+
+  ctx->bits = bits;
+  ctx->word = word;
+
+  assert(done <= 2);
+  
+  return done;
+}
+
+/* Returns the number of output characters. DST should point to an
+ * area of size at least BASE64_ENCODE_LENGTH(length). */
+unsigned
+base64_encode_update(struct base64_encode_ctx *ctx,
+		     uint8_t *dst,
+		     unsigned length,
+		     const uint8_t *src)
+{
+  unsigned done = 0;
+  unsigned left = length;
+  unsigned left_over;
+  unsigned bulk;
+  
+  while (ctx->bits && left)
+    {
+      left--;
+      done += base64_encode_single(ctx, dst + done, *src++);
+    }
+  
+  left_over = left % 3;
+  bulk = left - left_over;
+  
+  if (bulk)
+    {
+      assert(!(bulk % 3));
+      
+      base64_encode_raw(dst + done, bulk, src);
+      done += BASE64_ENCODE_RAW_LENGTH(bulk);
+      src += bulk;
+      left = left_over;
+    }
+
+  while (left)
+    {
+      left--;
+      done += base64_encode_single(ctx, dst + done, *src++);
+    }
+
+  assert(done <= BASE64_ENCODE_LENGTH(length));
+
+  return done;
+}
+
+/* DST should point to an area of size at least
+ * BASE64_ENCODE_FINAL_SIZE */
+unsigned
+base64_encode_final(struct base64_encode_ctx *ctx,
+		    uint8_t *dst)
+{
+  unsigned done = 0;
+  unsigned bits = ctx->bits;
+  
+  if (bits)
+    {
+      dst[done++] = ENCODE(ctx->word << (6 - ctx->bits));
+      for (; bits < 6; bits += 2)
+	dst[done++] = '=';
+
+      ctx->bits = 0;
+    }
+
+  assert(done <= BASE64_ENCODE_FINAL_LENGTH);
+  return done;
+}