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 13

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 10

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 9

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 11

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 8

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 6

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 7

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 74

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 82

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 35

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 144

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 68

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 164

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 119

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