--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/asn1/der/object_identifier/der_encode_object_identifier.c	Sat Feb 03 08:20:34 2007 +0000
@@ -0,0 +1,111 @@
+/* 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.com
+ */
+#include "tomcrypt.h"
+
+/**
+  @file der_encode_object_identifier.c
+  ASN.1 DER, Encode Object Identifier, Tom St Denis
+*/
+
+#ifdef LTC_DER
+/**
+  Encode an OID
+  @param words   The words to encode  (upto 32-bits each)
+  @param nwords  The number of words in the OID
+  @param out     [out] Destination of OID data
+  @param outlen  [in/out] The max and resulting size of the OID
+  @return CRYPT_OK if successful
+*/
+int der_encode_object_identifier(unsigned long *words, unsigned long  nwords,
+                                 unsigned char *out,   unsigned long *outlen)
+{
+   unsigned long i, x, y, z, t, mask, wordbuf;
+   int           err;
+
+   LTC_ARGCHK(words  != NULL);
+   LTC_ARGCHK(out    != NULL);
+   LTC_ARGCHK(outlen != NULL);
+
+   /* check length */
+   if ((err = der_length_object_identifier(words, nwords, &x)) != CRYPT_OK) {
+      return err;
+   }
+   if (x > *outlen) {
+      *outlen = x;
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   /* compute length to store OID data */
+   z = 0;
+   wordbuf = words[0] * 40 + words[1];
+   for (y = 1; y < nwords; y++) {
+       t = der_object_identifier_bits(wordbuf);
+       z += t/7 + ((t%7) ? 1 : 0) + (wordbuf == 0 ? 1 : 0);
+       if (y < nwords - 1) {
+          wordbuf = words[y + 1];
+       }
+   }
+
+   /* store header + length */
+   x = 0; 
+   out[x++] = 0x06;
+   if (z < 128) {
+      out[x++] = (unsigned char)z;
+   } else if (z < 256) {
+      out[x++] = 0x81;
+      out[x++] = (unsigned char)z;
+   } else if (z < 65536UL) {
+      out[x++] = 0x82;
+      out[x++] = (unsigned char)((z>>8)&255);
+      out[x++] = (unsigned char)(z&255);
+   } else {
+      return CRYPT_INVALID_ARG;
+   }
+
+   /* store first byte */
+    wordbuf = words[0] * 40 + words[1];   
+    for (i = 1; i < nwords; i++) {
+        /* store 7 bit words in little endian */
+        t    = wordbuf & 0xFFFFFFFF;
+        if (t) {
+           y    = x;
+           mask = 0;
+           while (t) {
+               out[x++] = (unsigned char)((t & 0x7F) | mask);
+               t    >>= 7;
+               mask  |= 0x80;  /* upper bit is set on all but the last byte */
+           }
+           /* now swap bytes y...x-1 */
+           z = x - 1;
+           while (y < z) {
+               t = out[y]; out[y] = out[z]; out[z] = (unsigned char)t;
+               ++y; 
+               --z;
+           }
+       } else {
+          /* zero word */
+          out[x++] = 0x00;
+       }
+       
+       if (i < nwords - 1) {
+          wordbuf = words[i + 1];
+       }
+   }
+
+   *outlen = x;
+   return CRYPT_OK;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/object_identifier/der_encode_object_identifier.c,v $ */
+/* $Revision: 1.6 $ */
+/* $Date: 2006/12/04 21:34:03 $ */