Class: Px4LogReader::MessageDescriptor

Inherits:
Object
  • Object
show all
Defined in:
lib/px4_log_reader/message_descriptor.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(attrs = {}) ⇒ MessageDescriptor

Returns a new instance of MessageDescriptor.



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# File 'lib/px4_log_reader/message_descriptor.rb', line 44

def initialize(attrs={})
  if attrs.keys.uniq.sort == [:name,:type,:length,:format,:fields].uniq.sort
    @name = attrs[:name]
    @type = attrs[:type]
    @length = attrs[:length]
    @format = attrs[:format]
    @format_specifier = MessageDescriptor.build_format_specifier( @format )
    fields = attrs[:fields]

    @field_list = MessageDescriptor.build_field_list( fields )
  elsif attrs.size > 0
    raise "Missing attributes"
  else
    @name = nil
    @type = nil
    @length = nil
    @format = nil

    @field_list = {}
  end
end

Instance Attribute Details

#field_list ⇒ Object (readonly)

Returns the value of attribute field_list.



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# File 'lib/px4_log_reader/message_descriptor.rb', line 41

def field_list
  @field_list
end

#format ⇒ Object (readonly)

Returns the value of attribute format.



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# File 'lib/px4_log_reader/message_descriptor.rb', line 40

def format
  @format
end

#format_specifier ⇒ Object (readonly)

Returns the value of attribute format_specifier.



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# File 'lib/px4_log_reader/message_descriptor.rb', line 42

def format_specifier
  @format_specifier
end

#length ⇒ Object (readonly)

Returns the value of attribute length.



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# File 'lib/px4_log_reader/message_descriptor.rb', line 39

def length
  @length
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/px4_log_reader/message_descriptor.rb', line 37

def name
  @name
end

#type ⇒ Object (readonly)

Returns the value of attribute type.



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# File 'lib/px4_log_reader/message_descriptor.rb', line 38

def type
  @type
end

Class Method Details

.build_field_list(fields) ⇒ Object 



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# File 'lib/px4_log_reader/message_descriptor.rb', line 105

def build_field_list( fields )
  field_list = {}
  fields.each_with_index do |field,index|
    field_list[field] = index
  end
  field_list
end

.build_format_specifier(px4_format_string) ⇒ Object 



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# File 'lib/px4_log_reader/message_descriptor.rb', line 113

def build_format_specifier( px4_format_string )
  format_specifier = ''

  px4_format_string.unpack('C*').each do |field_format|
    case field_format
    when 0x66 # 'f'
      format_specifier << 'F'
    when 0x71, 0x51 # 'q', 'Q'
      format_specifier << 'l!'
    when 0x69, 0x4C, 0x65 # 'i', 'L', 'e'
      format_specifier << 'l'
    when 0x49, 0x45 # 'I', 'E'
      format_specifier << 'L'
    when 0x62 # 'b'
      format_specifier << 'c'
    when 0x42, 0x4D # 'B', 'M'
      format_specifier << 'C'
    when 0x68, 0x63 # 'h', 'c'
      format_specifier << 's'
    when 0x48, 0x43 # 'H', 'C'
      format_specifier << 'S'
    when 0x6E # 'n'
      format_specifier << 'A4'
    when 0x4E # 'N'
      format_specifier << 'A16'
    when 0x5A # 'Z'
      format_specifier << 'A64'
    else
      raise InvalidDescriptorError.new(
        "Invalid format specifier: '#{ '0x%02X' % field_format }' in #{px4_format_string}")
    end
  end

  return format_specifier
end

Instance Method Details

#from_message(message) ⇒ Object 



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# File 'lib/px4_log_reader/message_descriptor.rb', line 66

def from_message( message )

      if message.descriptor.type != 0x80

raise InvalidDescriptorError.new(
  'Invalid descriptor type for format specifier message' )

      elsif message.fields.count != 5

raise InvalidDescriptorError.new(
  "Invalid field count for format specifier message: expected 5 fields, found #{message.fields.count}" )

      end

      @type, @length, @name, @format, fields_string = message.fields

      @format_specifier = MessageDescriptor.build_format_specifier( @format )

      unless fields_string.empty?

fields = fields_string.split(',')

if fields.length != @format.length
  raise InvalidDescriptorError.new(
    "Field count must match format length: expected #{@format.length}; found #{fields.length}")
else
  @field_list = MessageDescriptor.build_field_list( fields )
end

      end
      
end

#pack_message(fields) ⇒ Object 



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# File 'lib/px4_log_reader/message_descriptor.rb', line 175

def pack_message( fields )

  if fields.count != @format.length
    raise "Descriptor format length must match message field count"
  end

  corrected_fields = fields.dup
  @format.unpack('C*').each_with_index do |field_format,index|
    case field_format
    when 0x4C # 'L'
      corrected_fields[index] /= 1.0E-7
    when 0x63, 0x43, 0x45 # 'c', 'C', 'E'
      corrected_fields[index] /= 1.0E-2
    else
    end
  end

  return corrected_fields.pack( @format_specifier )
end

#to_message ⇒ Object 



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# File 'lib/px4_log_reader/message_descriptor.rb', line 99

def to_message
  return LogMessage.new( FORMAT_MESSAGE, [ @type, @length, @name, @format, @fields_string ] )
end

#to_s ⇒ Object 



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# File 'lib/px4_log_reader/message_descriptor.rb', line 195

def to_s
  puts "#{@name}( #{@type} ):"
  puts "   length = #{@length}"
  puts "   format = #{@format}"
  @field_list.each do |name,index|
    puts "   field#{index} = #{name}"
  end
end

#unpack_message(message_data) ⇒ Object 



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# File 'lib/px4_log_reader/message_descriptor.rb', line 150

def unpack_message( message_data )

  if @format_specifier.nil?
    @format_specifier = MessageDescriptor.build_format_specifier( @format )
  end

  fields = message_data.unpack( @format_specifier )

  @format.unpack('C*').each_with_index do |field_format,index|
    case field_format
    when 0x4C # 'L'
      fields[index] = fields[index] * 1.0E-7
    when 0x63, 0x43, 0x45 # 'c', 'C', 'E'
      fields[index] = fields[index] * 1.0E-2
    else
    end
  end

  if fields.nil? || fields.empty?
    raise "No fields"
  end

  return LogMessage.new( self, fields )
end