Class: DBF::VersionConfig

Inherits:
Object
  • Object
show all
Defined in:
lib/dbf/version_config.rb

Constant Summary collapse

DBASE2_HEADER_SIZE = 
8
DBASE3_HEADER_SIZE = 
32
DBASE7_HEADER_SIZE = 
68
VERSIONS = 
{
  '02' => 'FoxBase',
  '03' => 'dBase III without memo file',
  '04' => 'dBase IV without memo file',
  '05' => 'dBase V without memo file',
  '07' => 'Visual Objects 1.x',
  '30' => 'Visual FoxPro',
  '32' => 'Visual FoxPro with field type Varchar or Varbinary',
  '31' => 'Visual FoxPro with AutoIncrement field',
  '43' => 'dBASE IV SQL table files, no memo',
  '63' => 'dBASE IV SQL system files, no memo',
  '7b' => 'dBase IV with memo file',
  '83' => 'dBase III with memo file',
  '87' => 'Visual Objects 1.x with memo file',
  '8b' => 'dBase IV with memo file',
  '8c' => 'dBase 7',
  '8e' => 'dBase IV with SQL table',
  'cb' => 'dBASE IV SQL table files, with memo',
  'f5' => 'FoxPro with memo file',
  'fb' => 'FoxPro without memo file'
}.freeze
FOXPRO_VERSIONS = 
{
  '30' => 'Visual FoxPro',
  '31' => 'Visual FoxPro with AutoIncrement field',
  'f5' => 'FoxPro with memo file',
  'fb' => 'FoxPro without memo file'
}.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(version) ⇒ VersionConfig

Returns a new instance of VersionConfig.



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# File 'lib/dbf/version_config.rb', line 40

def initialize(version)
  @version = version
end

Instance Attribute Details

#version ⇒ Object (readonly)

Returns the value of attribute version.



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# File 'lib/dbf/version_config.rb', line 38

def version
  @version
end

Instance Method Details

#column_layout ⇒ Object

:nodoc:



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# File 'lib/dbf/version_config.rb', line 82

def column_layout # :nodoc:
  case version
  when '02' then [header_size * 2, 'A11 a C', [0]]
  when '04', '8c' then [48, 'A32 a C C x13', []]
  else [header_size, 'A11 a x4 C2', []]
  end
end

#foxpro? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dbf/version_config.rb', line 59

def foxpro?
  FOXPRO_VERSIONS.key?(version)
end

#header_size ⇒ Object 



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# File 'lib/dbf/version_config.rb', line 48

def header_size
  case version
  when '02'
    DBASE2_HEADER_SIZE
  when '04', '8c'
    DBASE7_HEADER_SIZE
  else
    DBASE3_HEADER_SIZE
  end
end

#memo_class ⇒ Object 



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# File 'lib/dbf/version_config.rb', line 63

def memo_class
  if foxpro?
    Memo::Foxpro
  else
    version == '83' ? Memo::Dbase3 : Memo::Dbase4
  end
end

#read_column_args(table, io) ⇒ Object

Returns the Column.new arguments for the next column descriptor, or nil when the file ends mid-descriptor. Unpacking a short descriptor would otherwise raise ArgumentError ("x outside of string").



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# File 'lib/dbf/version_config.rb', line 74

def read_column_args(table, io)
  size, format, defaults = column_layout
  data = io.read(size)
  return nil unless data && data.bytesize == size

  [table, *data.unpack(format), *defaults]
end

#version_description ⇒ Object 



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# File 'lib/dbf/version_config.rb', line 44

def version_description
  VERSIONS[version]
end