OpenLCP/acn/pdu.h

/*
  pdu.h

  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.
*/
#pragma once

#include <functional>
#include <memory>
#include <vector>
#include "pdu-stream.h"

namespace ACN {
namespace PDU {

/**
 * @brief 2.4.1. Flags
 *
 * Flags is a 4-bit field containing flags L, V, H and D which declare how
 * the PDU is packed.
 */
struct pdu_flags
{
  bool hasLength  : 1;
  bool hasVector  : 1;
  bool hasHeader  : 1;
  bool hasData    : 1;
  pdu_flags() {};
  pdu_flags(uint8_t);
};


/**
 * @brief The pdu_base_member struct
 */
struct pdu_base_member
{
    virtual ~pdu_base_member() {};
    virtual size_t streamSize() = 0;
    virtual void   iStream(Stream) = 0;
    virtual void   oStream(Stream) const = 0;
};


/**
 * @brief The pdu_header struct
 */
struct pdu_header : public pdu_base_member {};


/**
 * @brief The pdu_data struct
 */
struct pdu_data : public pdu_base_member {};


/**
 * @brief The Pdu class
 *
 *  All PDU share common structure of:
 *   flags, length, vector,
 *   and protocol specific header/data.
 *
 * Flag values indicate if lenght, vector, header or data
 * are present in the PDU, or if they should be inherited from the
 * preceding PDU.
 */
class Pdu : public pdu_base_member {
public:
  Pdu(size_t vector_size);
  ~Pdu();

  // getters
  const pdu_flags flags()  {return flags_;}
  const uint32_t  length() {return length_;}
  const uint32_t  vector(); // may inherit
  pdu_header    * header(); // may inherit
  pdu_data      * data();   // may inherit
  std::shared_ptr<Pdu> parent() {return parent_;}
  Stream          stream() {return stream_;}
  virtual size_t  streamSize() override;
  virtual void    iStream(Stream) override;
  virtual void    oStream(Stream) const override;

  // setters
  void setParent (std::shared_ptr<Pdu> pdu) {parent_ = pdu;}
  void setInherit(std::shared_ptr<Pdu> pdu) {inherit_ = pdu;}

protected:
  pdu_flags       flags_;
  uint32_t        length_;
  uint32_t        vector_;
  size_t          vector_size_;
  std::shared_ptr<Pdu> parent_  = nullptr;
  std::shared_ptr<Pdu> inherit_ = nullptr;
  pdu_header         * header_  = nullptr;
  pdu_data           * data_    = nullptr;
  Stream          stream_;
};


/**
 * @brief Callback that understands how to proccess a PDU type.
 * @tparam T PDU decendant subclass
 */
template <typename T>
using Handler = std::function<void(std::shared_ptr<T>)>;


/**
 * @brief PDU::pdu_data subclass that encapsulates other PDU.
 * @tparam T PDU decendant subclass
 */
template <typename T>
struct Block : public pdu_data
{
    std::shared_ptr<std::vector<std::shared_ptr<T>>> pdu
        = std::shared_ptr<std::vector<std::shared_ptr<T>>>(
                                         new std::vector<std::shared_ptr<T>>);
    size_t streamSize() {
        size_t s = 0;
        for (auto &child : *pdu)
            s += child->streamSize();
        return s;
    }
    void iStream(Stream s) {        //!< you should call readBlock() directly.
        readBlock(s, nullptr);
    };
    void oStream(Stream s) const {
        for ( const auto & child : *pdu )
            child->oStream(s);
    };
    void readBlock(Stream s, std::shared_ptr<PDU::Pdu> parent = nullptr) {
      while(s->good()) {
        std::shared_ptr<T> p(new T());
        p->iStream(s);
        if (s->fail())              // stream failed during pdu read
          break;
        if (p->stream()->fail())    // pdu buffer failed
          continue;
        if (parent)                 // set parent
          p->setParent(parent);
        if (!pdu->empty())          // set inheritee
          p->setInherit(pdu->back());
        pdu->push_back(p);          // add to block
      }
    }

};


} // PDU
} // ACN