Class: RMARC::MarcStreamWriter

Inherits:
Object
  • Object
show all
Defined in:
lib/rmarc/marc_stream_writer.rb

Overview

Class for writing MARC record objects in ISO 2709 format.

The following example reads a file with MARC XML records and outputs the record set in ISO 2709 format: 

writer = RMARC::MarcStreamWriter.new(STDOUT)
reader = RMARC::MarcXmlReader.new("file.xml")
while reader.has_next
    record = reader.next()
    writer.write_record(record)
end

Instance Method Summary collapse

Constructor Details

#initialize(output) ⇒ MarcStreamWriter

Default constructor.



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# File 'lib/rmarc/marc_stream_writer.rb', line 39

def initialize(output)
  @output = output
end

Instance Method Details

#write_record(record) ⇒ Object

Writes a single record to the given output stream.



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# File 'lib/rmarc/marc_stream_writer.rb', line 44

def write_record(record)
  data = ""
  dir = ""
  prev = 0
  
  record.fields.each { 
    |field| 
    if field.tag.to_i < 10
      data << field.data << Constants.FT
    else
      data << field.ind1 << field.ind2
      field.subfields.each { |subf| data << Constants.US << subf.code << subf.data }
      data << Constants.FT
    end
    len = data.length
    dir << field.tag << "%04d" % (len - prev) << "%05d" % prev
    prev = len
  }
  dir << Constants.FT
  
  leader = record.leader
  leader.base_address = 24 + dir.length
  leader.record_length = leader.base_address + data.length + 1
  
  @output.write(leader.to_s << dir << data << Constants.RT)
end