BaseInflator.h

/*
 * 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 2 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 Library General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * BaseInflator.h
 * Provides the base class for inflating PDU blocks.
 * Copyright (C) 2007 Simon Newton
 *
 * The BaseInflator takes care of most of the heavy lifting when inflating PDU
 * blocks. To create a specific Inflator, subclass BaseInflator and implement
 * the Id() and DecodeHeader() methods.
 */

#ifndef LIBS_ACN_BASEINFLATOR_H_
#define LIBS_ACN_BASEINFLATOR_H_

#include <stdint.h>
#include <map>
#include "libs/acn/HeaderSet.h"
#include "libs/acn/PDU.h"

namespace ola {
namespace acn {

class BaseInflatorTest;


class InflatorInterface {
 public:
 virtual ~InflatorInterface() {}

 /*
 * Return the id for this inflator
 */
 virtual uint32_t Id() const = 0;

 /*
 * Parse a block of PDU data
 */
 virtual unsigned int InflatePDUBlock(HeaderSet *headers,
 const uint8_t *data,
 unsigned int len) = 0;
};


/*
 * An abstract PDU inflator
 */
class BaseInflator : public InflatorInterface {
 friend class BaseInflatorTest;

 public:
 explicit BaseInflator(PDU::vector_size v_size = PDU::FOUR_BYTES);
 virtual ~BaseInflator() {}

 /*
 * Add another inflator as a handler. Ownership is not transferred.
 */
 bool AddInflator(InflatorInterface *inflator);

 /*
 * Return the inflator used for a particular vector.
 */
 class InflatorInterface *GetInflator(uint32_t vector) const;

 /*
 * Parse a block of PDU data
 */
 virtual unsigned int InflatePDUBlock(HeaderSet *headers,
 const uint8_t *data,
 unsigned int len);

 // masks for the flag fields
 // This indicates a 20 bit length field (default is 12 bits)
 static const uint8_t LFLAG_MASK = 0x80;
 // This masks the first 4 bits of the length field
 static const uint8_t LENGTH_MASK = 0x0F;

 protected:
 uint32_t m_last_vector;
 bool m_vector_set;
 PDU::vector_size m_vector_size; // size of the vector field
 // map protos to inflators
 std::map<uint32_t, InflatorInterface*> m_proto_map;

 // Reset repeated pdu fields
 virtual void ResetPDUFields();
 virtual void ResetHeaderField() = 0;

 // determine the length of a pdu
 bool DecodeLength(const uint8_t *data,
 unsigned int data_length,
 unsigned int *pdu_length,
 unsigned int *bytes_used) const;

 // determine the vector of a pdu
 bool DecodeVector(uint8_t flags,
 const uint8_t *data,
 unsigned int length,
 uint32_t *vector,
 unsigned int *bytes_used);

 // Decode a header block and adds any PduHeaders to the HeaderSet object
 virtual bool DecodeHeader(HeaderSet *headers,
 const uint8_t *data,
 unsigned int len,
 unsigned int *bytes_used) = 0;

 // parse the body of a pdu
 bool InflatePDU(HeaderSet *headers,
 uint8_t flags,
 const uint8_t *data,
 unsigned int pdu_len);

 // called after the header is parsed
 virtual bool PostHeader(uint32_t vector, const HeaderSet &headers);

 // called in the absence of an inflator to handle the pdu data
 virtual bool HandlePDUData(uint32_t vector,
 const HeaderSet &headers,
 const uint8_t *data,
 unsigned int pdu_len);
};
} // namespace acn
} // namespace ola
#endif // LIBS_ACN_BASEINFLATOR_H_