Module: GPS_PVT::Util::BitOp

Defined in:
lib/gps_pvt/util.rb

Constant Summary collapse

MASK = 
(1..8).collect{|i| (1 << i) - 1}.reverse

Class Method Summary collapse

Class Method Details

.extract(src_bytes, bits_list, offset = 0) ⇒ Object 



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# File 'lib/gps_pvt/util.rb', line 128

def BitOp.extract(src_bytes, bits_list, offset = 0)
  res = []
  bits_list.inject(offset.divmod(8) + [offset]){|(qM, rM, skip), bits|
    qL, rL = (skip += bits).divmod(8)
    v = src_bytes[qM] & MASK[rM]
    res << if rL > 0 then
      src_bytes[(qM+1)..qL].inject(v){|v2, b| (v2 << 8) | b} >> (8 - rL)
    else
      src_bytes[(qM+1)..(qL-1)].inject(v){|v2, b| (v2 << 8) | b}
    end
    [qL, rL, skip]
  }
  res
end