Class: Omnizip::Formats::Ole::AllocationTable::Big

Inherits:
AllocationTable
  • Object
show all
Defined in:
lib/omnizip/formats/ole/allocation_table.rb

Overview

Big allocation table (BBAT)

Manages large blocks (typically 512 bytes) for files >= 4096 bytes.

Instance Method Summary collapse

Constructor Details

#initialize(ole) ⇒ Big

Returns a new instance of Big.



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# File 'lib/omnizip/formats/ole/allocation_table.rb', line 229

def initialize(ole)
  super
  @block_size = 1 << @ole.header.b_shift
  @io = @ole.io
end

Instance Method Details

#blocks_to_ranges(blocks, size = nil) ⇒ Array<Array<Integer, Integer>>

Big blocks are -1 based to avoid clashing with header

Parameters:

  • blocks (Array<Integer>) —

    Block indices

  • size (Integer, nil) (defaults to: nil) —

    Optional size

Returns:

  • (Array<Array<Integer, Integer>>) —

    Byte ranges



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# File 'lib/omnizip/formats/ole/allocation_table.rb', line 240

def blocks_to_ranges(blocks, size = nil)
  return [] if blocks.empty?

  blocks = blocks[0, (size.to_f / block_size).ceil] if size
  ranges = blocks.map { |i| [block_size * (i + 1), block_size] }
  ranges.last[1] -= ((ranges.length * block_size) - size) if ranges.last && size
  ranges
end