OpenLCP/acn/pdu.cpp

/*
  pdu.cpp

  Copyright (c) 2020 Kevin Matz (kevin.matz@gmail.com)

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/

#include "pdu.h"
#include <cmath>

namespace ACN {
namespace PDU {

Pdu::Pdu(Stream stream, size_t vector_size)
  : flags_(stream->peek())
{
  header_  = 0;
  data_    = 0;
  parent_  = 0;
  inherit_ = 0; // pointer to previous PDU in block

  // read length and vector off of the stream
  // abort if the remaining PDU length isn't available
  if (stream->available() < (flags_.hasLength ? 3 : 2)) {
    stream->setstate(stream->rdstate() | std::ios_base::failbit);
    return;
  }
  readLength(stream);
  if (!length_ || length_ > std::pow(2, (8 * (flags_.hasLength ? 3 : 2)) - 4)) {
    stream->setstate(stream->rdstate() | std::ios_base::failbit);
    return;
  }

  // length includes the flags, length, and vector
  // calculate the remaining length of the PDU
  int len = length_ - (flags_.hasLength ? 3 : 2);

  // abort if the remaining PDU length isn't available
  if (!stream->good() || stream->available() < len) {
    stream->setstate(stream->rdstate() | std::ios_base::failbit);
    return;
  }

  // create a stream buffer for the header and data
  buffer_ = Stream(new pdu_stream(stream->data(), len));
  if (buffer_->available() != len) {
    stream->setstate(stream->rdstate() | std::ios_base::failbit);
    return;
  }

  // fast-forward the input stream
  for (int i = 0; i < len; i++)
    stream->get();
  if (!stream->available())
    stream->setstate(stream->rdstate() | std::ios_base::eofbit);

  if (flags_.hasVector)
    readVector(vector_size);
}


Pdu::~Pdu() {
  if (header_) delete header_;
  if (data_) delete data_;
}


const uint32_t Pdu::vector() {
  if (flags_.hasVector)
    return vector_;
  if (inherit_ != nullptr)
    return inherit_->vector();
  return 0;
}


pdu_header * Pdu::header() {
  if (flags_.hasHeader)
    return header_;
  if (inherit_ != nullptr)
    return inherit_->header();
  return 0;
}


pdu_data * Pdu::data() {
  if (flags_.hasData)
    return data_;
  if (inherit_ != nullptr)
    return inherit_->data();
  return 0;
}


void Pdu::readLength(Stream stream) {
  length_ = stream->read16() & 0x0fff; // high 4 bytes are flags
  if (flags_.hasLength)
    length_ = (length_ << 8 ) | stream->read8();
}


void Pdu::readVector(uint8_t vector_size) {
  vector_ = 0;
  for (int o = vector_size - 1; o >= 0; o--)
    vector_ |= (buffer_->read8() << (8 * o));
}


pdu_flags::pdu_flags(uint8_t val) {
  hasLength = (val >> 7) & 0b1;
  hasVector = (val >> 6) & 0b1;
  hasHeader = (val >> 5) & 0b1;
  hasData   = (val >> 4) & 0b1;
};


uint8_t pdu_stream::read8() {
  uint8_t ret = 0;
  if (available() < (int)sizeof(ret)) {
    setstate(rdstate() | std::ios_base::failbit);
    return 0;
  }
  ret = get();
  if (!available())
    setstate(rdstate() | std::ios_base::eofbit);
  return ret;
}


uint16_t pdu_stream::read16() {
  uint16_t ret = 0;
  if (available() < (int)sizeof(ret)) {
    setstate(rdstate() | std::ios_base::failbit);
    return 0;
  }
  ret |= get() << 8;
  ret |= get();
  if (!available())
    setstate(rdstate() | std::ios_base::eofbit);
  return ret;
}


uint32_t pdu_stream::read32() {
  uint32_t ret = 0;
  if (available() < (int)sizeof(ret)) {
    setstate(rdstate() | std::ios_base::failbit);
    return 0;
  }
  ret |= get() << 24;
  ret |= get() << 16;
  ret |= get() << 6;
  ret |= get();
  if (!available())
    setstate(rdstate() | std::ios_base::eofbit);
  return ret;
}

} // PDU
} // ACN