1 files changed, 100 insertions, 0 deletions
diff --git a/libotr/libgcrypt-1.8.7/cipher/cipher-ofb.c b/libotr/libgcrypt-1.8.7/cipher/cipher-ofb.c
new file mode 100644
index 0000000..f821d1b
--- /dev/null
+++ b/libotr/libgcrypt-1.8.7/cipher/cipher-ofb.c
@@ -0,0 +1,100 @@
+/* cipher-ofb.c  - Generic OFB mode implementation
+ * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
+ *               2005, 2007, 2008, 2009, 2011 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt 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.
+ *
+ * Libgcrypt 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 this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include "g10lib.h"
+#include "cipher.h"
+#include "bufhelp.h"
+#include "./cipher-internal.h"
+
+
+gcry_err_code_t
+_gcry_cipher_ofb_encrypt (gcry_cipher_hd_t c,
+                          unsigned char *outbuf, size_t outbuflen,
+                          const unsigned char *inbuf, size_t inbuflen)
+{
+  unsigned char *ivp;
+  gcry_cipher_encrypt_t enc_fn = c->spec->encrypt;
+  size_t blocksize = c->spec->blocksize;
+  unsigned int burn, nburn;
+
+  /* Tell compiler that we require a cipher with a 64bit or 128 bit block
+   * length, to allow better optimization of this function.  */
+  if (blocksize > 16 || blocksize < 8 || blocksize & (8 - 1))
+    return GPG_ERR_INV_LENGTH;
+
+  if (outbuflen < inbuflen)
+    return GPG_ERR_BUFFER_TOO_SHORT;
+
+  if ( inbuflen <= c->unused )
+    {
+      /* Short enough to be encoded by the remaining XOR mask. */
+      /* XOR the input with the IV */
+      ivp = c->u_iv.iv + blocksize - c->unused;
+      buf_xor(outbuf, ivp, inbuf, inbuflen);
+      c->unused -= inbuflen;
+      return 0;
+    }
+
+  burn = 0;
+
+  if( c->unused )
+    {
+      inbuflen -= c->unused;
+      ivp = c->u_iv.iv + blocksize - c->unused;
+      buf_xor(outbuf, ivp, inbuf, c->unused);
+      outbuf += c->unused;
+      inbuf += c->unused;
+      c->unused = 0;
+    }
+
+  /* Now we can process complete blocks. */
+  while ( inbuflen >= blocksize )
+    {
+      /* Encrypt the IV (and save the current one). */
+      nburn = enc_fn ( &c->context.c, c->u_iv.iv, c->u_iv.iv );
+      burn = nburn > burn ? nburn : burn;
+      buf_xor(outbuf, c->u_iv.iv, inbuf, blocksize);
+      outbuf += blocksize;
+      inbuf += blocksize;
+      inbuflen -= blocksize;
+    }
+  if ( inbuflen )
+    { /* process the remaining bytes */
+      nburn = enc_fn ( &c->context.c, c->u_iv.iv, c->u_iv.iv );
+      burn = nburn > burn ? nburn : burn;
+      c->unused = blocksize;
+      c->unused -= inbuflen;
+      buf_xor(outbuf, c->u_iv.iv, inbuf, inbuflen);
+      outbuf += inbuflen;
+      inbuf += inbuflen;
+      inbuflen = 0;
+    }
+
+  if (burn > 0)
+    _gcry_burn_stack (burn + 4 * sizeof(void *));
+
+  return 0;
+}