--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/asn1/der/choice/der_decode_choice.c	Wed Mar 08 13:23:58 2006 +0000
@@ -0,0 +1,168 @@
+/* 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_choice.c
+  ASN.1 DER, decode a CHOICE, Tom St Denis
+*/
+
+#ifdef LTC_DER
+
+/**
+   Decode a CHOICE
+   @param in       The DER encoded input
+   @param inlen    [in/out] The size of the input and resulting size of read type
+   @param list     The list of items to decode
+   @param outlen   The number of items in the list
+   @return CRYPT_OK on success
+*/
+int der_decode_choice(const unsigned char *in,   unsigned long *inlen,
+                            ltc_asn1_list *list, unsigned long  outlen)
+{
+   unsigned long size, x, z;
+   void          *data;
+
+   LTC_ARGCHK(in    != NULL);
+   LTC_ARGCHK(inlen != NULL);
+   LTC_ARGCHK(list  != NULL);
+
+   /* get blk size */
+   if (*inlen < 2) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* set all of the "used" flags to zero */
+   for (x = 0; x < outlen; x++) {
+       list[x].used = 0;
+   }
+
+   /* now scan until we have a winner */
+   for (x = 0; x < outlen; x++) {
+       size = list[x].size;
+       data = list[x].data;
+
+       switch (list[x].type) {
+           case LTC_ASN1_INTEGER:
+               if (der_decode_integer(in, *inlen, data) == CRYPT_OK) {
+                  if (der_length_integer(data, &z) == CRYPT_OK) {
+                      list[x].used = 1;
+                      *inlen       = z;
+                      return CRYPT_OK;
+                  }
+               }
+               break;
+
+           case LTC_ASN1_SHORT_INTEGER:
+               if (der_decode_short_integer(in, *inlen, data) == CRYPT_OK) {
+                  if (der_length_short_integer(size, &z) == CRYPT_OK) {
+                      list[x].used = 1;
+                      *inlen       = z;
+                      return CRYPT_OK;
+                  }
+               }
+               break;
+
+           case LTC_ASN1_BIT_STRING:
+               if (der_decode_bit_string(in, *inlen, data, &size) == CRYPT_OK) {
+                  if (der_length_bit_string(size, &z) == CRYPT_OK) {
+                     list[x].used = 1;
+                     list[x].size = size;
+                     *inlen       = z;
+                     return CRYPT_OK;
+                  }
+               }
+               break;
+
+           case LTC_ASN1_OCTET_STRING:
+               if (der_decode_octet_string(in, *inlen, data, &size) == CRYPT_OK) {
+                  if (der_length_octet_string(size, &z) == CRYPT_OK) {
+                     list[x].used = 1;
+                     list[x].size = size;
+                     *inlen       = z;
+                     return CRYPT_OK;
+                  }
+               }
+               break;
+
+           case LTC_ASN1_NULL:
+               if (*inlen == 2 && in[x] == 0x05 && in[x+1] == 0x00) {
+                  *inlen = 2;
+                  return CRYPT_OK;
+               }
+               break;
+                  
+           case LTC_ASN1_OBJECT_IDENTIFIER:
+               if (der_decode_object_identifier(in, *inlen, data, &size) == CRYPT_OK) {
+                  if (der_length_object_identifier(data, size, &z) == CRYPT_OK) {
+                     list[x].used = 1;
+                     list[x].size = size;
+                     *inlen       = z;
+                     return CRYPT_OK;
+                  }
+               }
+               break;
+
+           case LTC_ASN1_IA5_STRING:
+               if (der_decode_ia5_string(in, *inlen, data, &size) == CRYPT_OK) {
+                  if (der_length_ia5_string(data, size, &z) == CRYPT_OK) {
+                     list[x].used = 1;
+                     list[x].size = size;
+                     *inlen       = z;
+                     return CRYPT_OK;
+                  }
+               }
+               break;
+
+
+           case LTC_ASN1_PRINTABLE_STRING:
+               if (der_decode_printable_string(in, *inlen, data, &size) == CRYPT_OK) {
+                  if (der_length_printable_string(data, size, &z) == CRYPT_OK) {
+                     list[x].used = 1;
+                     list[x].size = size;
+                     *inlen       = z;
+                     return CRYPT_OK;
+                  }
+               }
+               break;
+
+           case LTC_ASN1_UTCTIME:
+               z = *inlen;
+               if (der_decode_utctime(in, &z, data) == CRYPT_OK) {
+                  list[x].used = 1;
+                  *inlen       = z;
+                  return CRYPT_OK;
+               }
+               break;
+
+           case LTC_ASN1_SEQUENCE:
+               if (der_decode_sequence(in, *inlen, data, size) == CRYPT_OK) {
+                  if (der_length_sequence(data, size, &z) == CRYPT_OK) {
+                     list[x].used = 1;
+                     *inlen       = z;
+                     return CRYPT_OK;
+                  }
+               }
+               break;
+
+           default:
+               return CRYPT_INVALID_ARG;
+       }
+   }
+
+   return CRYPT_INVALID_PACKET;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/choice/der_decode_choice.c,v $ */
+/* $Revision: 1.4 $ */
+/* $Date: 2005/06/19 11:25:01 $ */