--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/asn1/der/object_identifier/der_decode_object_identifier.c	Sat Mar 25 12:59:58 2006 +0000
@@ -0,0 +1,99 @@
+/* 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, [email protected], http://libtomcrypt.org
+ */
+#include "tomcrypt.h"
+
+/**
+  @file der_decode_object_identifier.c
+  ASN.1 DER, Decode Object Identifier, Tom St Denis
+*/
+
+#ifdef LTC_DER
+/**
+  Decode OID data and store the array of integers in words
+  @param in      The OID DER encoded data
+  @param inlen   The length of the OID data
+  @param words   [out] The destination of the OID words
+  @param outlen  [in/out] The number of OID words
+  @return CRYPT_OK if successful
+*/
+int der_decode_object_identifier(const unsigned char *in,    unsigned long  inlen,
+                                       unsigned long *words, unsigned long *outlen)
+{
+   unsigned long x, y, t, len;
+
+   LTC_ARGCHK(in     != NULL);
+   LTC_ARGCHK(words  != NULL);
+   LTC_ARGCHK(outlen != NULL);
+
+   /* header is at least 3 bytes */
+   if (inlen < 3) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* must be room for at least two words */
+   if (*outlen < 2) {
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   /* decode the packet header */
+   x = 0;
+   if ((in[x++] & 0x1F) != 0x06) {
+      return CRYPT_INVALID_PACKET;
+   }
+   
+   /* get the length */
+   if (in[x] < 128) {
+      len = in[x++]; 
+   } else {
+       if (in[x] < 0x81 || in[x] > 0x82) {
+          return CRYPT_INVALID_PACKET;
+       }
+       y   = in[x++] & 0x7F;
+       len = 0;
+       while (y--) {
+          len = (len << 8) | (unsigned long)in[x++];
+       }
+   }
+
+   if (len < 1 || (len + x) > inlen) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* decode word1 and word2 */
+   --len;
+   t = in[x++];
+   words[0] = t/40;
+   words[1] = t%40;
+
+   /* decode rest */
+   y = 2;
+   t = 0;
+   while (len--) {
+       t = (t << 7) | (in[x] & 0x7F);
+       if (!(in[x++] & 0x80)) {
+           /* store t */
+           if (y >= *outlen) {
+              return CRYPT_BUFFER_OVERFLOW;
+           }
+           words[y++] = t;
+           t          = 0;
+       }
+   }
+       
+   *outlen = y;
+   return CRYPT_OK;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/object_identifier/der_decode_object_identifier.c,v $ */
+/* $Revision: 1.1 $ */
+/* $Date: 2005/05/16 15:08:11 $ */