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module DBF
module Memo
class Base
BLOCK_HEADER_SIZE = 8
BLOCK_SIZE = 512
def self.open(filename, version)
new(File.open(filename, 'rb'), version)
end
def initialize(data, version)
@data = data
@version = version
end
def get(start_block)
return nil unless start_block > 0
build_memo start_block
end
def close
@data.close && @data.closed?
end
def closed?
@data.closed?
end
private
def offset(start_block) # :nodoc:
start_block * block_size
end
def content_size(memo_size) # :nodoc:
(memo_size - block_size) + BLOCK_HEADER_SIZE
end
def block_content_size # :nodoc:
@block_content_size ||= block_size - BLOCK_HEADER_SIZE
end
def block_size # :nodoc:
BLOCK_SIZE
end
end
end
end
|
