/*
 * Copyright (C) 2011-2021 Free Software Foundation, Inc.
 *
 * This file is part of LIBTASN1.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Written by Simon Josefsson
 *
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "libtasn1.h"

struct tv
{
  int bitlen;
  const char *bitstr;
  int derlen;
  const char *der;
};

static const struct tv tv[] = {
  {0, "", 2, "\x01\x00"},
  {1, "\x00", 3, "\x02\x07\x00"},
  {2, "\x00", 3, "\x02\x06\x00"},
  {3, "\x00", 3, "\x02\x05\x00"},
  {4, "\x00", 3, "\x02\x04\x00"},
  {5, "\x00", 3, "\x02\x03\x00"},
  {6, "\x00", 3, "\x02\x02\x00"},
  {7, "\x00", 3, "\x02\x01\x00"},
  {8, "\x00\x00", 3, "\x02\x00\x00"},
  {9, "\x00\x00", 4, "\x03\x07\x00\x00"},
  {10, "\x00\x00", 4, "\x03\x06\x00\x00"},
  {11, "\x00\x00", 4, "\x03\x05\x00\x00"},
  {12, "\x00\x00", 4, "\x03\x04\x00\x00"},
  {13, "\x00\x00", 4, "\x03\x03\x00\x00"},
  {14, "\x00\x00", 4, "\x03\x02\x00\x00"},
  {15, "\x00\x00", 4, "\x03\x01\x00\x00"},
  {16, "\x00\x00", 4, "\x03\x00\x00\x00"},
  {17, "\x00\x00\x00", 5, "\x04\x07\x00\x00\x00"},
  {18, "\x00\x00\x00", 5, "\x04\x06\x00\x00\x00"},
  {19, "\x00\x00\x00", 5, "\x04\x05\x00\x00\x00"},
  {1, "\xFF", 3, "\x02\x07\x80"},
  {2, "\xFF", 3, "\x02\x06\xc0"},
  {3, "\xFF", 3, "\x02\x05\xe0"},
  {4, "\xFF", 3, "\x02\x04\xf0"},
  {5, "\xFF", 3, "\x02\x03\xf8"},
  {6, "\xFF", 3, "\x02\x02\xfc"},
  {7, "\xFF", 3, "\x02\x01\xfe"},
  {8, "\xFF\xFF", 3, "\x02\x00\xff"},
  {9, "\xFF\xFF", 4, "\x03\x07\xff\x80"},
  {10, "\xFF\xFF", 4, "\x03\x06\xff\xc0"},
  {11, "\xFF\xFF", 4, "\x03\x05\xff\xe0"},
  {12, "\xFF\xFF", 4, "\x03\x04\xff\xf0"},
  {13, "\xFF\xFF", 4, "\x03\x03\xff\xf8"},
  {14, "\xFF\xFF", 4, "\x03\x02\xff\xfc"},
  {15, "\xFF\xFF", 4, "\x03\x01\xff\xfe"},
  {16, "\xFF\xFF", 4, "\x03\x00\xff\xff"},
  {17, "\xFF\xFF\xFF", 5, "\x04\x07\xff\xff\x80"},
  {18, "\xFF\xFF\xFF", 5, "\x04\x06\xff\xff\xc0"},
  {19, "\xFF\xFF\xFF", 5, "\x04\x05\xff\xff\xe0"},
};

int
main (int argc, char *argv[])
{
  int result;
  unsigned char der[100];
  unsigned char str[100];
  int der_len = sizeof (der);
  int str_size = sizeof (str);
  int ret_len, bit_len;
  size_t i;

  /* Dummy test */

  asn1_bit_der (NULL, 0, der, &der_len);
  result = asn1_get_bit_der (der, 0, &ret_len, str, str_size, &bit_len);
  if (result != ASN1_GENERIC_ERROR)
    {
      fprintf (stderr, "asn1_get_bit_der zero\n");
      return 1;
    }

  /* Encode short strings with increasing bit lengths */

  for (i = 0; i < sizeof (tv) / sizeof (tv[0]); i++)
    {
      /* Encode */

      asn1_bit_der ((const unsigned char *) tv[i].bitstr, tv[i].bitlen,
		    der, &der_len);

#if 0
      {
	size_t j;
	for (j = 0; j < der_len; j++)
	  printf ("\\x%02x", der[j]);
	printf ("\n");
      }
#endif

      if (der_len != tv[i].derlen || memcmp (der, tv[i].der, der_len) != 0)
	{
	  fprintf (stderr, "asn1_bit_der iter %lu\n", (unsigned long) i);
	  return 1;
	}

      /* Decode it */

      result = asn1_get_bit_der (der, der_len, &ret_len, str,
				 str_size, &bit_len);
      if (result != ASN1_SUCCESS || ret_len != tv[i].derlen
	  || bit_len != tv[i].bitlen)
	{
	  fprintf (stderr, "asn1_get_bit_der iter %lu, err: %d\n", (unsigned long) i, result);
	  return 1;
	}
    }


  /* Decode sample from "A Layman's Guide to a Subset of ASN.1, BER,
     and DER" section 5.4 "BIT STRING": "The BER encoding of the BIT
     STRING value "011011100101110111" can be any of the following,
     among others, depending on the choice of padding bits, the form
     of length octets [...]".
   */

  /* 03 04 06 6e 5d c0  DER encoding */

  memcpy (der, "\x04\x06\x6e\x5d\xc0", 5);
  der_len = 5;

  result = asn1_get_bit_der (der, der_len, &ret_len, str, str_size, &bit_len);
  if (result != ASN1_SUCCESS || ret_len != 5
      || bit_len != 18 || memcmp (str, "\x6e\x5d\xc0", 3) != 0)
    {
      fprintf (stderr, "asn1_get_bit_der example\n");
      return 1;
    }

  der_len = sizeof (der);
  asn1_bit_der (str, bit_len, der, &der_len);
  if (der_len != 5 || memcmp (der, "\x04\x06\x6e\x5d\xc0", 5) != 0)
    {
      fprintf (stderr, "asn1_bit_der example roundtrip\n");
      return 1;
    }

  /* 03 04 06 6e 5d e0 padded with "100000" */

  memcpy (der, "\x04\x06\x6e\x5d\xe0", 5);
  der_len = 5;

  result = asn1_get_bit_der (der, der_len, &ret_len, str, str_size, &bit_len);
  if (result != ASN1_SUCCESS || ret_len != 5
      || bit_len != 18 || memcmp (str, "\x6e\x5d\xe0", 3) != 0)
    {
      fprintf (stderr, "asn1_get_bit_der example padded\n");
      return 1;
    }

  der_len = sizeof (der);
  asn1_bit_der (str, bit_len, der, &der_len);
  if (der_len != 5 || memcmp (der, "\x04\x06\x6e\x5d\xc0", 5) != 0)
    {
      fprintf (stderr, "asn1_bit_der example roundtrip\n");
      return 1;
    }

  /* 03 81 04 06 6e 5d c0 long form of length octets */

  memcpy (der, "\x81\x04\x06\x6e\x5d\xc0", 6);
  der_len = 6;

  result = asn1_get_bit_der (der, der_len, &ret_len, str, str_size, &bit_len);

  if (result != ASN1_SUCCESS || ret_len != 6
      || bit_len != 18 || memcmp (str, "\x6e\x5d\xc0", 3) != 0)
    {
      fprintf (stderr, "asn1_get_bit_der example long form\n");
      return 1;
    }

  der_len = sizeof (der);
  asn1_bit_der (str, bit_len, der, &der_len);
  if (der_len != 5 || memcmp (der, "\x04\x06\x6e\x5d\xc0", 5) != 0)
    {
      fprintf (stderr, "asn1_bit_der example roundtrip\n");
      return 1;
    }

  return 0;
}