--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/asn1/der/utf8/der_decode_utf8_string.c	Sat Feb 03 08:20:30 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_decode_utf8_string.c
+  ASN.1 DER, encode a UTF8 STRING, Tom St Denis
+*/
+
+
+#ifdef LTC_DER
+
+/**
+  Store a UTF8 STRING
+  @param in      The DER encoded UTF8 STRING
+  @param inlen   The size of the DER UTF8 STRING
+  @param out     [out] The array of utf8s stored (one per char)
+  @param outlen  [in/out] The number of utf8s stored
+  @return CRYPT_OK if successful
+*/
+int der_decode_utf8_string(const unsigned char *in,  unsigned long inlen,
+                                       wchar_t *out, unsigned long *outlen)
+{
+   wchar_t       tmp;
+   unsigned long x, y, z, len;
+
+   LTC_ARGCHK(in     != NULL);
+   LTC_ARGCHK(out    != NULL);
+   LTC_ARGCHK(outlen != NULL);
+
+   /* must have header at least */
+   if (inlen < 2) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* check for 0x0C */
+   if ((in[0] & 0x1F) != 0x0C) {
+      return CRYPT_INVALID_PACKET;
+   }
+   x = 1;
+
+   /* decode the length */
+   if (in[x] & 0x80) {
+      /* valid # of bytes in length are 1,2,3 */
+      y = in[x] & 0x7F;
+      if ((y == 0) || (y > 3) || ((x + y) > inlen)) {
+         return CRYPT_INVALID_PACKET;
+      }
+
+      /* read the length in */
+      len = 0;
+      ++x;
+      while (y--) {
+         len = (len << 8) | in[x++];
+      }
+   } else {
+      len = in[x++] & 0x7F;
+   }
+
+   if (len + x > inlen) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* proceed to decode */
+   for (y = 0; x < inlen; ) {
+      /* get first byte */
+      tmp = in[x++];
+ 
+      /* count number of bytes */
+      for (z = 0; (tmp & 0x80) && (z <= 4); z++, tmp = (tmp << 1) & 0xFF);
+      
+      if (z > 4 || (x + (z - 1) > inlen)) {
+         return CRYPT_INVALID_PACKET;
+      }
+
+      /* decode, grab upper bits */
+      tmp >>= z;
+
+      /* grab remaining bytes */
+      if (z > 1) { --z; }
+      while (z-- != 0) {
+         if ((in[x] & 0xC0) != 0x80) {
+            return CRYPT_INVALID_PACKET;
+         }
+         tmp = (tmp << 6) | ((wchar_t)in[x++] & 0x3F);
+      }
+
+      if (y > *outlen) {
+         *outlen = y;
+         return CRYPT_BUFFER_OVERFLOW;
+      }
+      out[y++] = tmp;
+   }
+   *outlen = y;
+
+   return CRYPT_OK;
+}
+ 
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/utf8/der_decode_utf8_string.c,v $ */
+/* $Revision: 1.7 $ */
+/* $Date: 2006/11/26 02:27:37 $ */