file_meta_sink.h

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/* -*- c++ -*- */
/*
 * Copyright 2012 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio 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 3, or (at your option)
 * any later version.
 *
 * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef INCLUDED_BLOCKS_FILE_META_SINK_H
#define INCLUDED_BLOCKS_FILE_META_SINK_H

#include <blocks/api.h>
#include <gr_sync_block.h>

namespace gr {
  namespace blocks {

    const char METADATA_VERSION = 0;
    const size_t METADATA_HEADER_SIZE = 149;

    enum gr_file_types {
      GR_FILE_BYTE=0,
      GR_FILE_CHAR=0,
      GR_FILE_SHORT=1,
      GR_FILE_INT,
      GR_FILE_LONG,
      GR_FILE_LONG_LONG,
      GR_FILE_FLOAT,
      GR_FILE_DOUBLE,
    };

    /*!
     * \brief Write stream to file with meta-data headers.
     * \ingroup file_operators_blk
     *
     * \details
     * These files represent data as binary information in between
     * meta-data headers. The headers contain information about the
     * type of data and properties of the data in the next segment of
     * samples. The information includes:
     *
     *   rx_rate (double): sample rate of data.
     *   rx_time (uint64_t, double): time stamp of first sample in segment.
     *   size (uint32_t): item size in bytes.
     *   type (gr_file_types as int32_t): data type.
     *   cplx (bool): Is data complex?
     *   strt (uint64_t): Starting byte of data in this segment.
     *   bytes (uint64_t): Size in bytes of data in this segment.
     *
     * Tags can be sent to the file to update the information, which
     * will create a new header. Headers are found by searching from
     * the first header (at position 0 in the file) and reading where
     * the data segment starts plus the data segment size. Following
     * will either be a new header or EOF.
     */
    class BLOCKS_API file_meta_sink : virtual public gr_sync_block
    {
    public:
      // gr::blocks::file_meta_sink::sptr
      typedef boost::shared_ptr<file_meta_sink> sptr;

      /*!
       * \brief Create a meta-data file sink.
       *
       * \param itemsize (size_t): Size of data type.
       * \param filename (string): Name of file to write data to.
       * \param samp_rate (double): Sample rate of data. If sample rate will be
       *    set by a tag, such as rx_tag from a UHD source, this is
       *    basically ignored.
       * \param relative_rate (double): Rate chance from source of sample
       *    rate tag to sink.
       * \param type (gr_file_types): Data type (int, float, etc.)
       * \param complex (bool): If data stream is complex
       * \param max_segment_size (size_t): Length of a single segment
       *    before the header is repeated (in items).
       * \param extra_dict (string): a serialized PMT dictionary of extra
       *    information. Currently not supported.
       * \param detached_header (bool): Set to true to store the header
       *    info in a separate file (named filename.hdr)
       */
      static sptr make(size_t itemsize, const std::string &filename,
                       double samp_rate=1, double relative_rate=1,
                       gr_file_types type=GR_FILE_FLOAT, bool complex=true,
                       size_t max_segment_size=1000000,
                       const std::string &extra_dict="",
                       bool detached_header=false);

      virtual bool open(const std::string &filename) = 0;
      virtual void close() = 0;
      virtual void do_update() = 0;

      virtual void set_unbuffered(bool unbuffered) = 0;
    };

  } /* namespace blocks */
} /* namespace gr */

#endif /* INCLUDED_BLOCKS_FILE_META_SINK_H */