/*
 *  anytun
 *
 *  The secure anycast tunneling protocol (satp) defines a protocol used
 *  for communication between any combination of unicast and anycast
 *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
 *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
 *  ethernet, ip, arp ...). satp directly includes cryptography and
 *  message authentication based on the methodes used by SRTP.  It is
 *  intended to deliver a generic, scaleable and secure solution for
 *  tunneling and relaying of packets of any protocol.
 *
 *
 *  Copyright (C) 2007 anytun.org <satp@wirdorange.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  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 (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <stdexcept>
#include <string>
#include <cstdio>
#include <iostream>

#include "datatypes.h"
#include "buffer.h"

Buffer::Buffer() : buf_(0), length_(0)
{  
}

Buffer::Buffer(u_int32_t length) : length_(length)
{
  buf_ = new u_int8_t[length_];
  if(buf_)
    std::memset(buf_, 0, length_);
  else 
    length_ = 0;
}

Buffer::Buffer(u_int8_t* data, u_int32_t length) : length_(length)
{
  buf_ = new u_int8_t[length_];
  if(buf_)
    std::memcpy(buf_, data, length_);
  else 
    length_ = 0;
}

Buffer::~Buffer()
{
  if(buf_)
    delete[] buf_;
}

Buffer::Buffer(const Buffer &src) : length_(src.length_)
{
  buf_ = new u_int8_t[length_];
  if(buf_)
    std::memcpy(buf_, src.buf_, length_);
  else 
    length_ = 0;
}

void Buffer::operator=(const Buffer &src)
{
  if(buf_)
    delete[] buf_;
 
  length_ = src.length_;
 
  buf_ = new u_int8_t[length_];
  if(buf_)
    std::memcpy(buf_, src.buf_, length_);
  else
    length_ = 0;
}

void Buffer::operator=(const seq_nr_t &src)
{
  if(buf_)
    delete[] buf_;

  length_ = sizeof(src);

  buf_ = new u_int8_t[length_];

  if( buf_ )
  {
    for( u_int32_t index = 0; index <= length_; index++ )
      buf_[index] = (src>>index) & 0xFF;
  }
  else
    length_ = 0;
}


void Buffer::operator=(const sender_id_t &src)
{
  if(buf_)
    delete[] buf_;

  length_ = sizeof(src);

  buf_ = new u_int8_t[length_];

  if( buf_ )
  {
    for( u_int32_t index = 0; index <= length_; index++ )
      buf_[index] = (src>>index) & 0xFF;
  }
  else
    length_ = 0;
}

u_int32_t Buffer::resizeFront(u_int32_t new_length)
{
  if(length_ == new_length)
    return length_;

  u_int8_t *tmp = new u_int8_t[new_length];
  if(!tmp)
    return length_;

  if(buf_)
  {
    u_int8_t *src=buf_, *dest=tmp;
    if(length_ < new_length)
      dest = &dest[new_length - length_];
    else
      src = &src[length_ - new_length];
    u_int32_t len = length_ < new_length ? length_ : new_length;
    std::memcpy(dest, src, len);
    delete[] buf_;
  }

  length_ = new_length;
  buf_ = tmp;
  return length_;
}

u_int32_t Buffer::resizeBack(u_int32_t new_length)
{
  if(length_ == new_length)
    return length_;

  u_int8_t *tmp = new u_int8_t[new_length];
  if(!tmp)
    return length_;

  if(buf_)
  {
    u_int32_t len = length_ < new_length ? length_ : new_length;
    std::memcpy(tmp, buf_, len);
    delete[] buf_;
  }

  length_ = new_length;
  buf_ = tmp;
  return length_;
}

u_int32_t Buffer::getLength() const
{
  return length_;
}

u_int8_t* Buffer::getBuf()
{
  return buf_;
}

u_int8_t& Buffer::operator[](u_int32_t index)
{
  if(index >= length_)
    throw std::out_of_range("buffer::operator[]");

  return buf_[index];
}

u_int8_t Buffer::operator[](u_int32_t index) const
{
  if(index >= length_)
    throw std::out_of_range("buffer::operator[] const");

  return buf_[index];
}

Buffer::operator u_int8_t*() // just for write/read tun
{
  return buf_;
}

void Buffer::printHexDump() const
{
  char text[10];

  for( u_int32_t index = 0; index < length_; index++ )
  {
    std::sprintf(text, "%#4x", buf_[index]);
    std::cout << text << " ";
    if( ((index+1) % 10) == 0 )
      std::cout << std::endl;
  }
}

Buffer Buffer::operator^(const Buffer &xor_by) const
{
  Buffer res(length_);
  if( xor_by.getLength() > length_ )
    throw std::out_of_range("buffer::operator^ const");

  for( u_int32_t index = 0; index < xor_by.getLength(); index++ )
    res[index] = buf_[index] ^ xor_by[index];
  
  return res;
}

Buffer Buffer::leftByteShift(u_int32_t width) const
{
  Buffer res(length_+width);

  for( u_int32_t index = 0; index < length_; index++ )
    res[index+width] = buf_[index];

  return res;
}

Buffer Buffer::rightByteShift(u_int32_t width) const
{
  Buffer res(length_);

  for( u_int32_t index = 0; index < length_-width; index++ )
    res[index] = buf_[index+width];

  return res;
}