Class: Ephem::PCK

Inherits:
Object
  • Object
show all
Defined in:
lib/ephem/pck.rb

Overview

Reads a binary PCK (DAF/PCK) orientation kernel: the orientation of one or more body frames over time, expressed as Euler angles.

Constant Summary collapse

DATA_TYPE_IDENTIFIER =

Index of the data type within a PCK summary descriptor ([start, end, body, reference_frame, data_type, start_i, end_i]).

4

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(daf:) ⇒ PCK

Returns a new instance of PCK.

Parameters:

Raises:

  • (ArgumentError) —

    if the DAF is nil



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# File 'lib/ephem/pck.rb', line 15

def initialize(daf:)
  raise ArgumentError, "DAF cannot be nil" if daf.nil?

  @daf = daf
  @segments = load_segments
  @bodies = build_bodies
end

Instance Attribute Details

#daf ⇒ Object (readonly)

Returns the value of attribute daf.



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# File 'lib/ephem/pck.rb', line 11

def daf
  @daf
end

#segments ⇒ Object (readonly)

Returns the value of attribute segments.



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# File 'lib/ephem/pck.rb', line 11

def segments
  @segments
end

Class Method Details

.open(path) ⇒ PCK

Opens a binary PCK file.

Parameters:

  • path (String) —

    Path to the PCK (.bpc) file

Returns:

Raises:

  • (ArgumentError) —

    if the file is not a binary PCK or cannot be read



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# File 'lib/ephem/pck.rb', line 28

def self.open(path)
  daf = IO::DAF.new(File.open(path, "rb"))
  unless daf.file_type == :pck
    raise ArgumentError, "#{path} is not a binary PCK (DAF/PCK) file"
  end

  new(daf: daf)
rescue Errno::EACCES => e
  raise ArgumentError, "File permission denied: #{path} (#{e.message})"
rescue
  daf&.close
  raise
end

Instance Method Details

#[](body) ⇒ Segments::OrientationSegment, Segments::OrientationGroup

Retrieves the orientation source for a body frame.

Parameters:

  • body (Integer) —

    NAIF frame ID of the oriented body

Returns:

Raises:

  • (KeyError) —

    if no segment is found for the given body



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# File 'lib/ephem/pck.rb', line 55

def [](body)
  @bodies.fetch(body) do
    raise KeyError, "No orientation segment found for body: #{body}"
  end
end

#close ⇒ void

This method returns an undefined value.



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# File 'lib/ephem/pck.rb', line 43

def close
  @daf&.close
  @segments&.each(&:clear_data)
end

#comments ⇒ String

Returns the comments stored in the PCK file.

Returns:

  • (String) —

    the comments stored in the PCK file



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# File 'lib/ephem/pck.rb', line 62

def comments
  @daf.comments
end

#each_segment {|segment| ... } ⇒ Enumerator

Returns if no block is given.

Yield Parameters:

Returns:

  • (Enumerator) —

    if no block is given



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# File 'lib/ephem/pck.rb', line 68

def each_segment(&block)
  return enum_for(:each_segment) unless block_given?

  @segments.each(&block)
end

#excerpt(output_path:, start_jd:, end_jd:, target_ids: nil, debug: false) ⇒ Object 



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# File 'lib/ephem/pck.rb', line 82

def excerpt(output_path:, start_jd:, end_jd:, target_ids: nil, debug: false)
  Excerpt
    .new(self)
    .extract(
      output_path: output_path,
      start_jd: start_jd,
      end_jd: end_jd,
      target_ids: target_ids,
      debug: debug
    )
end

#to_s ⇒ String

Returns a description of the PCK file and its segments.

Returns:

  • (String) —

    a description of the PCK file and its segments



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# File 'lib/ephem/pck.rb', line 75

def to_s
  <<~DESCRIPTION
    PCK file with #{@segments.size} segments:
    #{@segments.join("\n")}
  DESCRIPTION
end