Module: LVM::Helpers

Included in:
Snapshot
Defined in:
lib/lvm/helpers.rb

Instance Method Summary collapse

Instance Method Details

#big_endian? ⇒ Boolean

Are we on a big-endian system? Needed for our htonq/ntohq methods

Returns:

  • (Boolean) 


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# File 'lib/lvm/helpers.rb', line 5

def big_endian?
	@big_endian ||= [1].pack("s") == [1].pack("n")
end

#dtohq(val) ⇒ Object

On-disk (LVM) format (which is little-endian) to host byte order



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# File 'lib/lvm/helpers.rb', line 20

def dtohq val
	big_endian? ? swap_longs(val) : val
end

#htonq(val) ⇒ Object 



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# File 'lib/lvm/helpers.rb', line 9

def htonq val
	# This won't work on a nUxi byte-order machine, but if you have one of
	# those, I'm guessing you've got bigger problems
	big_endian? ? val : swap_longs(val)
end

#ntohq(val) ⇒ Object 



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# File 'lib/lvm/helpers.rb', line 15

def ntohq val
	big_endian? ? val : swap_longs(val)
end

#swap_longs(val) ⇒ Object 



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# File 'lib/lvm/helpers.rb', line 24

def swap_longs val
	[val].pack("Q").reverse.unpack("Q").first
end