Module: VORuby::VOTable::Castable

Included in:
V1_0::Param, V1_0::Td, V1_1::Param, V1_1::Td
Defined in:
lib/voruby/votable/votable.rb

Overview

Some helper methods for converting string values that have an associated data type (like TDs do through their associated FIELD).

Instance Method Summary collapse

Instance Method Details

#as_obj(txt, datatype, arraysize = nil) ⇒ Object

Much like #cast but understands arrays.



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# File 'lib/voruby/votable/votable.rb', line 208

def as_obj(txt, datatype, arraysize=nil)
  raise "Unable to determine datatype" if !datatype
  
  txt_list = arraysize ? txt.split(/\s+/) : [txt]
  values_list = []
  
  # character string, do nothing
  return txt if datatype == 'char' or datatype == 'unicodeChar'
  
  # complex values are a bit different
  if datatype == 'floatComplex' || datatype == 'doubleComplex'
    txt_list = txt.split(/\s+/)
    complex_numbers = []
    i = 0
    (0...txt_list.size/2).each do |n|
      complex_numbers << Complex.new(txt_list[i].to_f, txt_list[i+1].to_f)
      i += 2
    end
    return arraysize ? complex_numbers : complex_numbers.first
  end
  
  txt_list.each do |component|
    values_list << cast(component, datatype)
  end
  
  arraysize ? values_list : values_list.first
end

#as_string(obj, datatype, arraysize = nil) ⇒ Object

Much like #convert_to_s but understands arrays.



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# File 'lib/voruby/votable/votable.rb', line 237

def as_string(obj, datatype, arraysize=nil)
  raise "Unable to determine datatype" if !datatype
  raise "Supposed to contain an array of size '#{arraysize}'" if arraysize and !obj.is_a?(Array)
  raise "Supposed to contain a single value" if !arraysize and obj.is_a?(Array)
  
  obj = [obj] if !obj.is_a?(Array)
  
  values = []
  obj.each do |val|
    values << convert_to_s(val, datatype)
  end
  
  values.join(' ')
end

#cast(txt, to = 'char') ⇒ Object

Convert a string value into its corresponding basic object representation, if appropriate. This does not work on array values, only on scalars. Native ruby types map to votable datatypes in the following way:

  • ‘boolean’ => boolean (i.e TrueClass or FalseClass)

  • ‘bit’ => Integer (1 or 0)

  • ‘unsignedByte’ => Integer representation of the byte

  • ‘short, ’int’, ‘long’ => Integer

  • ‘char’, ‘unicodeChar’ => String

  • ‘float’, ‘double’ => Float or Bignum

  • ‘floatComplex’, ‘doubleComplex’ => Complex



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# File 'lib/voruby/votable/votable.rb', line 171

def cast(txt, to='char')
  case to
  when 'boolean'
    txt == '1' || txt.downcase == 'true' || txt.downcase == 't'
  when 'bit'          then txt.to_i
  when 'unsignedByte' then txt[0]
  when 'short'        then txt.to_i
  when 'int'          then txt.to_i
  when 'long'         then txt.to_i
  when 'double'       then txt.to_f
  when 'float'        then txt.to_f
  else
    txt
  end
end

#convert_to_s(val, from = 'char') ⇒ Object

Serialize a ruby object to the format that is correct for a votable.



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# File 'lib/voruby/votable/votable.rb', line 189

def convert_to_s(val, from='char')
  case from
  when 'boolean'
    (val.is_a?(TrueClass) or val.to_s.downcase =~ /^t/ or val.to_s == '1') ?
      'true' : 'false'
  when 'bit'            then val.to_i.to_s
  when 'short'          then val.to_i.to_s
  when 'int'            then val.to_i.to_s
  when 'long'           then val.to_i.to_s
  when 'float'          then val.to_f.to_s
  when 'double'         then val.to_f.to_s
  when 'floatComplex'   then "#{val.real} #{val.image}"
  when 'doubleComplex'  then "#{val.real} #{val.image}"
  else
    val.to_s
  end
end