1 files changed, 108 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/pk/asn1/der/integer/der_length_integer.c b/core/lib/libtomcrypt/src/pk/asn1/der/integer/der_length_integer.c
new file mode 100644
index 0000000..7205a9d
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+++ b/core/lib/libtomcrypt/src/pk/asn1/der/integer/der_length_integer.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2001-2007, Tom St Denis
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
+ */
+#include "tomcrypt.h"
+
+/**
+  @file der_length_integer.c
+  ASN.1 DER, get length of encoding, Tom St Denis
+*/
+
+
+#ifdef LTC_DER
+/**
+  Gets length of DER encoding of num
+  @param num    The int to get the size of
+  @param outlen [out] The length of the DER encoding for the given integer
+  @return CRYPT_OK if successful
+*/
+int der_length_integer(void *num, unsigned long *outlen)
+{
+   unsigned long z, len;
+   int           leading_zero;
+
+   LTC_ARGCHK(num     != NULL);
+   LTC_ARGCHK(outlen  != NULL);
+
+   if (mp_cmp_d(num, 0) != LTC_MP_LT) {
+      /* positive */
+
+      /* we only need a leading zero if the msb of the first byte is one */
+      if ((mp_count_bits(num) & 7) == 0 || mp_iszero(num) == LTC_MP_YES) {
+         leading_zero = 1;
+      } else {
+         leading_zero = 0;
+      }
+
+      /* size for bignum */
+      z = len = leading_zero + mp_unsigned_bin_size(num);
+   } else {
+      /* it's negative */
+      /* find power of 2 that is a multiple of eight and greater than count bits */
+      z = mp_count_bits(num);
+      z = z + (8 - (z & 7));
+      if (((mp_cnt_lsb(num)+1)==mp_count_bits(num)) && ((mp_count_bits(num)&7)==0)) --z;
+      len = z = z >> 3;
+   }
+
+   /* now we need a length */
+   if (z < 128) {
+      /* short form */
+      ++len;
+   } else {
+      /* long form (relies on z != 0), assumes length bytes < 128 */
+      ++len;
+
+      while (z) {
+         ++len;
+         z >>= 8;
+      }
+   }
+
+   /* we need a 0x02 to indicate it's INTEGER */
+   ++len;
+
+   /* return length */
+   *outlen = len;
+   return CRYPT_OK;
+}
+
+#endif
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */