/*
* OctetString
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/symkey.h>
#include <botan/rng.h>
#include <botan/hex.h>
#include <algorithm>

namespace Botan {

/*
* Create an OctetString from RNG output
*/
OctetString::OctetString(RandomNumberGenerator& rng,
                         size_t len)
   {
   rng.random_vec(m_data, len);
   }

/*
* Create an OctetString from a hex string
*/
OctetString::OctetString(const std::string& hex_string)
   {
   if(!hex_string.empty())
      {
      m_data.resize(1 + hex_string.length() / 2);
      m_data.resize(hex_decode(m_data.data(), hex_string));
      }
   }

/*
* Create an OctetString from a byte string
*/
OctetString::OctetString(const uint8_t in[], size_t n)
   {
   m_data.assign(in, in + n);
   }

namespace {

uint8_t odd_parity_of(uint8_t x)
   {
   uint8_t f = x | 0x01;
   f ^= (f >> 4);
   f ^= (f >> 2);
   f ^= (f >> 1);

   return (x & 0xFE) ^ (f & 0x01);
   }

}

/*
* Set the parity of each key byte to odd
*/
void OctetString::set_odd_parity()
   {
   for(size_t j = 0; j != m_data.size(); ++j)
      m_data[j] = odd_parity_of(m_data[j]);
   }

/*
* Hex encode an OctetString
*/
std::string OctetString::to_string() const
   {
   return hex_encode(m_data.data(), m_data.size());
   }

/*
* XOR Operation for OctetStrings
*/
OctetString& OctetString::operator^=(const OctetString& k)
   {
   if(&k == this) { zeroise(m_data); return (*this); }
   xor_buf(m_data.data(), k.begin(), std::min(length(), k.length()));
   return (*this);
   }

/*
* Equality Operation for OctetStrings
*/
bool operator==(const OctetString& s1, const OctetString& s2)
   {
   return (s1.bits_of() == s2.bits_of());
   }

/*
* Unequality Operation for OctetStrings
*/
bool operator!=(const OctetString& s1, const OctetString& s2)
   {
   return !(s1 == s2);
   }

/*
* Append Operation for OctetStrings
*/
OctetString operator+(const OctetString& k1, const OctetString& k2)
   {
   secure_vector<uint8_t> out;
   out += k1.bits_of();
   out += k2.bits_of();
   return OctetString(out);
   }

/*
* XOR Operation for OctetStrings
*/
OctetString operator^(const OctetString& k1, const OctetString& k2)
   {
   secure_vector<uint8_t> out(std::max(k1.length(), k2.length()));

   copy_mem(out.data(), k1.begin(), k1.length());
   xor_buf(out.data(), k2.begin(), k2.length());
   return OctetString(out);
   }

}