Class: TCD::LookupTables

Inherits:
Object
  • Object
show all
Defined in:
lib/tcd/lookup_tables.rb

Overview

Reader for TCD lookup tables (fixed-size string arrays).

TCD v2 stores string tables in this order after the 4-byte checksum:

  1. Level units (level_unit_types × level_unit_size) - exact count

  2. Direction units (dir_unit_types × dir_unit_size) - exact count

  3. Restrictions (max_restriction_types × restriction_size) - reads until “__END__”

  4. v1 only: Pedigrees - skipped in v2

  5. Timezones (max_tzfiles × tzfile_size) - reads until “__END__”

  6. Countries (max_countries × country_size) - reads until “__END__”

  7. Datums (max_datum_types × datum_size) - reads until “__END__”

  8. v2 only: Legalese (max_legaleses × legalese_size) - reads until “__END__”

  9. Constituent names (constituents × constituent_size) - exact count

  10. Constituent speeds (bit-packed)

  11. Equilibrium arguments (bit-packed)

  12. Node factors (bit-packed)

  13. Station records (bit-packed)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io, header) ⇒ LookupTables

Returns a new instance of LookupTables.



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# File 'lib/tcd/lookup_tables.rb', line 30

def initialize(io, header)
    @io = io
    @header = header
    load_tables
end

Instance Attribute Details

#constituent_data_offset ⇒ Object (readonly)

Positions tracked for the reader



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# File 'lib/tcd/lookup_tables.rb', line 27

def constituent_data_offset
  @constituent_data_offset
end

#constituents ⇒ Object (readonly)

Returns the value of attribute constituents.



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# File 'lib/tcd/lookup_tables.rb', line 23

def constituents
  @constituents
end

#countries ⇒ Object (readonly)

Returns the value of attribute countries.



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# File 'lib/tcd/lookup_tables.rb', line 24

def countries
  @countries
end

#datums ⇒ Object (readonly)

Returns the value of attribute datums.



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# File 'lib/tcd/lookup_tables.rb', line 23

def datums
  @datums
end

#direction_units ⇒ Object (readonly)

Returns the value of attribute direction_units.



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# File 'lib/tcd/lookup_tables.rb', line 22

def direction_units
  @direction_units
end

#legalese ⇒ Object (readonly)

Returns the value of attribute legalese.



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# File 'lib/tcd/lookup_tables.rb', line 23

def legalese
  @legalese
end

#level_units ⇒ Object (readonly)

Returns the value of attribute level_units.



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# File 'lib/tcd/lookup_tables.rb', line 22

def level_units
  @level_units
end

#restrictions ⇒ Object (readonly)

Returns the value of attribute restrictions.



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# File 'lib/tcd/lookup_tables.rb', line 22

def restrictions
  @restrictions
end

#station_records_offset ⇒ Object (readonly)

Where station records start



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# File 'lib/tcd/lookup_tables.rb', line 28

def station_records_offset
  @station_records_offset
end

#timezones ⇒ Object (readonly)

Returns the value of attribute timezones.



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# File 'lib/tcd/lookup_tables.rb', line 24

def timezones
  @timezones
end

Instance Method Details

#constituent(idx) ⇒ Object 



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# File 'lib/tcd/lookup_tables.rb', line 42

def constituent(idx);    safe_lookup(@constituents, idx); end

#country(idx) ⇒ Object 



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# File 'lib/tcd/lookup_tables.rb', line 43

def country(idx);        safe_lookup(@countries, idx); end

#datum(idx) ⇒ Object 



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# File 'lib/tcd/lookup_tables.rb', line 41

def datum(idx);          safe_lookup(@datums, idx); end

#direction_unit(idx) ⇒ Object 



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# File 'lib/tcd/lookup_tables.rb', line 38

def direction_unit(idx); safe_lookup(@direction_units, idx); end

#legalese_text(idx) ⇒ Object 



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# File 'lib/tcd/lookup_tables.rb', line 40

def legalese_text(idx);  safe_lookup(@legalese, idx); end

#level_unit(idx) ⇒ Object

Lookup by index with bounds checking



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# File 'lib/tcd/lookup_tables.rb', line 37

def level_unit(idx);     safe_lookup(@level_units, idx); end

#restriction(idx) ⇒ Object 



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# File 'lib/tcd/lookup_tables.rb', line 39

def restriction(idx);    safe_lookup(@restrictions, idx); end

#timezone(idx) ⇒ Object

Timezone strings in TCD files have a leading colon (e.g., “:America/New_York”) Strip it to return standard IANA timezone names



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# File 'lib/tcd/lookup_tables.rb', line 47

def timezone(idx)
    tz = safe_lookup(@timezones, idx)
    tz&.sub(/^:/, '')
end