Class: Fit4Ruby::FitFile

Inherits:
Object
  • Object
show all
Includes:
CRC16
Defined in:
lib/fit4ruby/FitFile.rb

Instance Method Summary collapse

Methods included from CRC16

#compute_crc, #write_crc

Constructor Details

#initialize ⇒ FitFile

Returns a new instance of FitFile.



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# File 'lib/fit4ruby/FitFile.rb', line 31

def initialize()
  @header = nil
end

Instance Method Details

#read(file_name, filter = nil) ⇒ Object 



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# File 'lib/fit4ruby/FitFile.rb', line 35

def read(file_name, filter = nil)
  @file_name = file_name
  definitions = {}
  begin
    io = ::File.open(file_name, 'rb')
  rescue StandardError => e
    Log.fatal "Cannot open FIT file '#{file_name}': #{e.message}"
  end

  entities = []
  begin
    while !io.eof?
      offset = io.pos

      header = FitHeader.read(io)

      # If the header has a CRC the header is not included in the
      # checksumed bytes. Otherwise it is included.
      check_crc(io, header.has_crc? ? header.header_size : 0,
                offset + header.end_pos)

      # Rewind back to the beginning of the data right after the header.
      io.seek(header.header_size)

      entity = FitFileEntity.new
      # This Array holds the raw data of the records that may be needed to
      # dump a human readable form of the FIT file.
      records = []
      # This hash will hold a counter for each record type. The counter is
      # incremented each time the corresponding record type is found.
      record_counters = Hash.new { 0 }
      while io.pos < offset + header.end_pos
        record = FitRecord.new(definitions, entity)
        record.read(io, entity, filter, record_counters)
        records << record if filter
      end
      # Skip the 2 CRC bytes
      io.seek(2, :CUR)

      header.dump if filter && filter.record_numbers.nil?
      dump_records(records) if filter

      entity.check
      entities << entity
    end
  ensure
    io.close
  end

  return nil if entities.empty?

  entities[0].top_level_record
end

#write(file_name, top_level_record) ⇒ Object 



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# File 'lib/fit4ruby/FitFile.rb', line 89

def write(file_name, top_level_record)
  begin
    io = ::File.open(file_name, 'wb+')
  rescue StandardError => e
    Log.fatal "Cannot open FIT file '#{file_name}': #{e.message}"
  end

  begin
    # Create a header object, but don't yet write it into the file.
    header = FitHeader.new
    start_pos = header.header_size

    # Move the pointer behind the header section.
    io.seek(start_pos)
    id_mapper = FitMessageIdMapper.new
    top_level_record.write(io, id_mapper)
    end_pos = io.pos

    crc = write_crc(io, start_pos, end_pos)

    # Complete the data of the header section and write it at the start of
    # the file.
    header.data_size = end_pos - start_pos
    io.seek(0)
    header.write(io)
  ensure
    io.close
  end
end