class RGeo::WKRep::WKBParser

This class provides the functionality of parsing a geometry from WKB (well-known binary) format. You may also customize the parser to recognize PostGIS EWKB extensions to the input, or Simple Features Specification 1.2 extensions for Z and M coordinates.

To use this class, create an instance with the desired settings and customizations, and call the parse method.

Configuration options

You must provide each parser with an RGeo::Feature::FactoryGenerator. It should understand the configuration options :srid, :has_z_coordinate, and :has_m_coordinate. You may also pass a specific RGeo::Feature::Factory, or nil to specify the default Cartesian FactoryGenerator.

The following additional options are recognized. These can be passed to the constructor, or set on the object afterwards.

:support_ewkb: Activate support for PostGIS EWKB type codes, which use high order bits in the type code to signal the presence of Z, M, and SRID values in the data. Default is false.
:support_wkb12: Activate support for SFS 1.2 extensions to the type codes, which use values greater than 1000 to signal the presence of Z and M values in the data. SFS 1.2 types such as triangle, tin, and polyhedralsurface are NOT yet supported. Default is false.
:ignore_extra_bytes: If true, extra bytes at the end of the data are ignored. If false (the default), extra bytes will trigger a parse error.
:default_srid: A SRID to pass to the factory generator if no SRID is present in the input. Defaults to nil (i.e. don’t specify a SRID).

Public Class Methods

new(factory_generator_=nil, opts_={}) click to toggle source

Create and configure a WKB parser. See the WKBParser documentation for the options that can be passed.

# File lib/rgeo/wkrep/wkb_parser.rb, line 83
def initialize(factory_generator_=nil, opts_={})
  if factory_generator_.kind_of?(Feature::Factory::Instance)
    @factory_generator = Feature::FactoryGenerator.single(factory_generator_)
    @exact_factory = factory_generator_
  elsif factory_generator_.respond_to?(:call)
    @factory_generator = factory_generator_
    @exact_factory = nil
  else
    @factory_generator = Cartesian.method(:preferred_factory)
    @exact_factory = nil
  end
  @support_ewkb = opts_[:support_ewkb] ? true : false
  @support_wkb12 = opts_[:support_wkb12] ? true : false
  @ignore_extra_bytes = opts_[:ignore_extra_bytes] ? true : false
  @default_srid = opts_[:default_srid]
end

Public Instance Methods

exact_factory() click to toggle source

If this parser was given an exact factory, returns it; otherwise returns nil.

# File lib/rgeo/wkrep/wkb_parser.rb, line 108
def exact_factory
  @exact_factory
end

factory_generator() click to toggle source

Returns the factory generator. See WKBParser for details.

# File lib/rgeo/wkrep/wkb_parser.rb, line 102
def factory_generator
  @factory_generator
end

ignore_extra_bytes?() click to toggle source

Returns true if this parser ignores extra bytes. See WKBParser for details.

# File lib/rgeo/wkrep/wkb_parser.rb, line 126
def ignore_extra_bytes?
  @ignore_extra_bytes
end

parse(data_) click to toggle source

Parse the given binary data or hexadecimal string, and return a geometry object.

The parse_hex method is a synonym, present for historical reasons but deprecated. Use parse instead.

# File lib/rgeo/wkrep/wkb_parser.rb, line 147
def parse(data_)
  if data_[0,1] =~ %r[0-9a-fA-F]/
    data_ = [data_].pack('H*')
  end
  @cur_has_z = nil
  @cur_has_m = nil
  @cur_srid = nil
  @cur_dims = 2
  @cur_factory = nil
  begin
    _start_scanner(data_)
    obj_ = _parse_object(false)
    unless @ignore_extra_bytes
      bytes_ = _bytes_remaining
      if bytes_ > 0
        raise Error::ParseError, "Found #{bytes_} extra bytes at the end of the stream."
      end
    end
  ensure
    _clean_scanner
  end
  obj_
end

Also aliased as: parse_hex

parse_hex(data_) click to toggle source

Alias for: parse

support_ewkb?() click to toggle source

Returns true if this parser supports EWKB. See WKBParser for details.

# File lib/rgeo/wkrep/wkb_parser.rb, line 114
def support_ewkb?
  @support_ewkb
end

support_wkb12?() click to toggle source

Returns true if this parser supports SFS 1.2 extensions. See WKBParser for details.

# File lib/rgeo/wkrep/wkb_parser.rb, line 120
def support_wkb12?
  @support_wkb12
end