Class: TCD::StationParser

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

Overview

Parser for station records from bit-packed binary data

Instance Method Summary collapse

Constructor Details

#initialize(bit_buffer, header, lookup_tables) ⇒ StationParser

Returns a new instance of StationParser.



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# File 'lib/tcd/station.rb', line 123

def initialize(bit_buffer, header, lookup_tables)
    @bit = bit_buffer
    @header = header
    @lookup = lookup_tables
end

Instance Method Details

#parse(record_number) ⇒ Object

Parse a single station record at current position



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# File 'lib/tcd/station.rb', line 130

def parse(record_number)
    start_pos = @bit.pos

    # ============================================
    # Partial header (common to all record types)
    # Per libtcd unpack_partial_tide_record()
    # ============================================

    # Record size and type
    record_size = @bit.read_uint(@header.record_size_bits)
    record_type = @bit.read_uint(@header.record_type_bits)

    # Geographic coordinates
    latitude = @bit.read_int(@header.latitude_bits).to_f / @header.latitude_scale
    longitude = @bit.read_int(@header.longitude_bits).to_f / @header.longitude_scale

    # Timezone file index (comes BEFORE name in TCD format)
    tzfile_idx = @bit.read_uint(@header.tzfile_bits)
    tzfile = @lookup.timezone(tzfile_idx)

    # Station name (null-terminated string)
    name = @bit.read_cstring

    # Reference station index (-1 for reference stations referring to themselves)
    reference_station = @bit.read_int(@header.station_bits)

    # ============================================
    # Extended fields (V2 format)
    # Per libtcd unpack_tide_record() case 2
    # ============================================

    # Country
    country_idx = @bit.read_uint(@header.country_bits)
    country = @lookup.country(country_idx)

    # Source string
    source = @bit.read_cstring

    # Restriction
    restriction_idx = @bit.read_uint(@header.restriction_bits)
    restriction = @lookup.restriction(restriction_idx)

    # Comments and notes
    comments = @bit.read_cstring
    notes = @bit.read_cstring

    # Legalese
    legalese_idx = @bit.read_uint(@header.legalese_bits)
    legalese = @lookup.legalese_text(legalese_idx)

    # Station ID fields
    station_id_context = @bit.read_cstring
    station_id = @bit.read_cstring

    # Date imported (YYYYMMDD integer)
    date_imported = @bit.read_uint(@header.date_bits)

    # xfields (extended fields string)
    xfields = @bit.read_cstring

    # Direction units
    direction_units_idx = @bit.read_uint(@header.direction_unit_bits)
    direction_units = @lookup.direction_unit(direction_units_idx)

    # Min/max direction
    min_direction = @bit.read_uint(@header.direction_bits)
    max_direction = @bit.read_uint(@header.direction_bits)
    min_direction = nil if min_direction == NULL_DIRECTION
    max_direction = nil if max_direction == NULL_DIRECTION

    # Level units
    level_units_idx = @bit.read_uint(@header.level_unit_bits)
    level_units = @lookup.level_unit(level_units_idx)

    # Build base station
    station = Station.new(
        record_number: record_number,
        record_size: record_size,
        record_type: record_type,
        latitude: latitude,
        longitude: longitude,
        tzfile: tzfile,
        name: name,
        reference_station: reference_station,
        country: country,
        source: source,
        restriction: restriction,
        comments: comments,
        notes: notes,
        legalese: legalese,
        station_id_context: station_id_context,
        station_id: station_id,
        date_imported: date_imported,
        xfields: xfields,
        direction_units: direction_units,
        min_direction: min_direction,
        max_direction: max_direction,
        level_units: level_units
    )

    # Parse type-specific fields
    if record_type == 1
        parse_reference_fields(station)
    else
        parse_subordinate_fields(station)
    end

    # Ensure we're at the right position for the next record
    # Record size is total bytes from start of record
    expected_end = start_pos + record_size
    @bit.seek(expected_end)

    station
end