Class: RGeo::CoordSys::CS::WKTParser

Inherits:
Object
  • Object
show all
Defined in:
lib/rgeo/coord_sys/cs/wkt_parser.rb

Overview

:nodoc:

Defined Under Namespace

Classes: ArgumentList, AuthorityClause, ExtensionClause, QuotedString, TypeString

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(str_) ⇒ WKTParser

Returns a new instance of WKTParser.



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# File 'lib/rgeo/coord_sys/cs/wkt_parser.rb', line 11

def initialize(str_)
  @scanner = ::StringScanner.new(str_)
  next_token
end

Instance Attribute Details

#cur_token ⇒ Object (readonly)

Returns the value of attribute cur_token.



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# File 'lib/rgeo/coord_sys/cs/wkt_parser.rb', line 181

def cur_token
  @cur_token
end

Instance Method Details

#consume_token_type(type_) ⇒ Object

:nodoc:



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# File 'lib/rgeo/coord_sys/cs/wkt_parser.rb', line 136

def consume_token_type(type_) # :nodoc:
  expect_token_type(type_)
  tok_ = @cur_token
  next_token
  tok_
end

#expect_token_type(type_) ⇒ Object

:nodoc:



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# File 'lib/rgeo/coord_sys/cs/wkt_parser.rb', line 143

def expect_token_type(type_) # :nodoc:
  unless type_ === @cur_token
    raise Error::ParseError, "#{type_.inspect} expected but #{@cur_token.inspect} found."
  end
end

#next_token ⇒ Object

:nodoc:



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# File 'lib/rgeo/coord_sys/cs/wkt_parser.rb', line 149

def next_token # :nodoc:
  @scanner.skip(/\s+/)
  case @scanner.peek(1)
  when '"'
    @scanner.getch
    @cur_token = QuotedString.new(@scanner.scan(/[^"]*/))
    @scanner.getch
  when ","
    @scanner.getch
    @cur_token = :comma
  when "(", "["
    @scanner.getch
    @cur_token = :begin
  when "]", ")"
    @scanner.getch
    @cur_token = :end
  when /[a-zA-Z]/
    @cur_token = TypeString.new(@scanner.scan(/[a-zA-Z]\w*/))
  when "", nil
    @cur_token = nil
  else
    @scanner.scan_until(/[^\s\(\)\[\],"]+/)
    token_ = @scanner.matched
    if token_ =~ /^[-+]?(\d+(\.\d*)?|\.\d+)(e[-+]?\d+)?$/
      @cur_token = token_.to_f
    else
      raise Error::ParseError, "Bad token: #{token_.inspect}"
    end
  end
  @cur_token
end

#parse(containing_type_ = nil) ⇒ Object

:nodoc:



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# File 'lib/rgeo/coord_sys/cs/wkt_parser.rb', line 16

def parse(containing_type_ = nil) # :nodoc:
  if @cur_token.is_a?(QuotedString) ||
    @cur_token.is_a?(::Numeric) ||
    (containing_type_ == "AXIS" && @cur_token.is_a?(TypeString))
    value_ = @cur_token
    next_token
    return value_
  end
  unless @cur_token.is_a?(TypeString)
    raise Error::ParseError("Found token #{@cur_token} when we expected a value")
  end
  type_ = @cur_token
  next_token
  consume_token_type(:begin)
  args_ = ArgumentList.new
  args_ << parse(type_)
  loop do
    break unless @cur_token == :comma
    next_token
    args_ << parse(type_)
  end
  consume_token_type(:end)
  obj_ = nil
  case type_
  when "AUTHORITY"
    obj_ = AuthorityClause.new(args_.shift(QuotedString), args_.shift(QuotedString))
  when "EXTENSION"
    obj_ = ExtensionClause.new(args_.shift(QuotedString), args_.shift(QuotedString))
  when "AXIS"
    obj_ = AxisInfo.create(args_.shift(QuotedString), args_.shift(TypeString))
  when "TOWGS84"
    bursa_wolf_params_ = args_.find_all(::Numeric)
    unless bursa_wolf_params_.size == 7
      raise Error::ParseError("Expected 7 Bursa Wolf parameters but found #{bursa_wolf_params_.size}")
    end
    obj_ = WGS84ConversionInfo.create(*bursa_wolf_params_)
  when "UNIT"
    case containing_type_
    when "GEOCCS", "VERT_CS", "PROJCS", "SPHEROID"
      klass_ = LinearUnit
    when "GEOGCS"
      klass_ = AngularUnit
    else
      klass_ = Unit
    end
    obj_ = klass_.create(args_.shift(QuotedString), args_.shift(::Numeric), *args_.create_optionals)
  when "PARAMETER"
    obj_ = ProjectionParameter.create(args_.shift(QuotedString), args_.shift(::Numeric))
  when "PRIMEM"
    obj_ = PrimeMeridian.create(args_.shift(QuotedString), nil, args_.shift(::Numeric), *args_.create_optionals)
  when "SPHEROID"
    obj_ = Ellipsoid.create_flattened_sphere(args_.shift(QuotedString), args_.shift(::Numeric), args_.shift(::Numeric), args_.find_first(LinearUnit), *args_.create_optionals)
  when "PROJECTION"
    name_ = args_.shift(QuotedString)
    obj_ = Projection.create(name_, name_, args_.find_all(ProjectionParameter), *args_.create_optionals)
  when "DATUM"
    name_ = args_.shift(QuotedString)
    ellipsoid_ = args_.find_first(Ellipsoid)
    to_wgs84_ = args_.find_first(WGS84ConversionInfo)
    obj_ = HorizontalDatum.create(name_, HD_GEOCENTRIC, ellipsoid_, to_wgs84_, *args_.create_optionals)
  when "VERT_DATUM"
    obj_ = VerticalDatum.create(args_.shift(QuotedString), args_.shift(::Numeric), *args_.create_optionals)
  when "LOCAL_DATUM"
    obj_ = LocalDatum.create(args_.shift(QuotedString), args_.shift(::Numeric), *args_.create_optionals)
  when "COMPD_CS"
    obj_ = CompoundCoordinateSystem.create(args_.shift(QuotedString), args_.shift(CoordinateSystem), args_.shift(CoordinateSystem), *args_.create_optionals)
  when "LOCAL_CS"
    name_ = args_.shift(QuotedString)
    local_datum_ = args_.find_first(LocalDatum)
    unit_ = args_.find_first(Unit)
    axes_ = args_.find_all(AxisInfo)
    unless axes_.size > 0
      raise Error::ParseError("Expected at least one AXIS in a LOCAL_CS")
    end
    obj_ = LocalCoordinateSystem.create(name_, local_datum_, unit_, axes_, *args_.create_optionals)
  when "GEOCCS"
    name_ = args_.shift(QuotedString)
    horizontal_datum_ = args_.find_first(HorizontalDatum)
    prime_meridian_ = args_.find_first(PrimeMeridian)
    linear_unit_ = args_.find_first(LinearUnit)
    axes_ = args_.find_all(AxisInfo)
    unless axes_.size == 0 || axes_.size == 3
      raise Error::ParseError("GEOCCS must contain either 0 or 3 AXIS parameters")
    end
    obj_ = GeocentricCoordinateSystem.create(name_, horizontal_datum_, prime_meridian_, linear_unit_, axes_[0], axes_[1], axes_[2], *args_.create_optionals)
  when "VERT_CS"
    name_ = args_.shift(QuotedString)
    vertical_datum_ = args_.find_first(VerticalDatum)
    linear_unit_ = args_.find_first(LinearUnit)
    axis_ = args_.find_first(AxisInfo)
    obj_ = VerticalCoordinateSystem.create(name_, vertical_datum_, linear_unit_, axis_, *args_.create_optionals)
  when "GEOGCS"
    name_ = args_.shift(QuotedString)
    horizontal_datum_ = args_.find_first(HorizontalDatum)
    prime_meridian_ = args_.find_first(PrimeMeridian)
    angular_unit_ = args_.find_first(AngularUnit)
    axes_ = args_.find_all(AxisInfo)
    unless axes_.size == 0 || axes_.size == 2
      raise Error::ParseError("GEOGCS must contain either 0 or 2 AXIS parameters")
    end
    obj_ = GeographicCoordinateSystem.create(name_, angular_unit_, horizontal_datum_, prime_meridian_, axes_[0], axes_[1], *args_.create_optionals)
  when "PROJCS"
    name_ = args_.shift(QuotedString)
    geographic_coordinate_system_ = args_.find_first(GeographicCoordinateSystem)
    projection_ = args_.find_first(Projection)
    parameters_ = args_.find_all(ProjectionParameter)
    projection_.instance_variable_get(:@parameters).concat(parameters_)
    linear_unit_ = args_.find_first(LinearUnit)
    axes_ = args_.find_all(AxisInfo)
    unless axes_.size == 0 || axes_.size == 2
      raise Error::ParseError("PROJCS must contain either 0 or 2 AXIS parameters")
    end
    obj_ = ProjectedCoordinateSystem.create(name_, geographic_coordinate_system_, projection_, linear_unit_, axes_[0], axes_[1], *args_.create_optionals)
  else
    raise Error::ParseError, "Unrecognized type: #{type_}"
  end
  args_.assert_empty
  obj_
end