can_mapper.cr

# TODO: Write documentation for `CanMapper`
module CanMapper
  VERSION = "0.1.0"

  # TODO: Put your code here
end


class BitMapper(T)
  property buffer : T 

  def initialize(@buffer : T)
  end

  def to_bytes(v : T, sze = sizeof(T))
    puts sze
    Bytes.new(pointerof(v).as(Pointer(UInt8)), sze)
  end

  def get_slice_le(start = 0, size = 16, prim = UInt32)
    shift = start 
    n = (@buffer >> shift) & ((1_u64<<size)-1)
    b = to_bytes(n)
    IO::ByteFormat::LittleEndian.decode(prim, b)
  end

  def get_slice_be(start = 0, size = 1, prim = UInt32)
    d, m = start.divmod(8)
    shift = (((64 - (d*8))-(7-m))) - size
  # 10101001,11001010,10101010,10110010,10111100,00101010,10101000,10100011
  # 10100011,10101000,00101010,10111100,10110010,10101010,11001010,10101001

    buffer = IO::ByteFormat::BigEndian.decode(T, to_bytes(@buffer))
    n = (buffer >> shift) & ((1_u64<<size)-1)
    b = to_bytes(n)
    IO::ByteFormat::LittleEndian.decode(prim, b)
  end

  # def set_slice_be(start = 0, size = 1, value)
  #
  #   d, m = start.divmod(8)
  #   shift = (((64 - (d*8))-(7-m))) - size
  # # 10101001,11001010,10101010,10110010,10111100,00101010,10101000,10100011
  # # 10100011,10101000,00101010,10111100,10110010,10101010,11001010,10101001
  #
  #   buffer = IO::ByteFormat::BigEndian.decode(T, to_bytes(@buffer))
  #   n = (buffer >> shift) & ((1_u64<<size)-1)
  #   b = to_bytes(n)
  #   IO::ByteFormat::LittleEndian.decode(prim, b)
  # end
end

buffer = 0b1010100111001010101010101011001010111100001010101010100010100011_u64
bm = BitMapper(UInt64).new(buffer)

bytes = buffer.to_s(2).chars.each_slice(8).map{|a| a.join}.join(",")
puts bytes
puts bytes.split(",").reverse.join(",")

puts bm.get_slice_le(0, 16, Int16)
puts bm.get_slice_le(0, 16, Int16).class
# puts bytes.reverse.join(",")
# puts bm.first_16_signed
# puts bm.first_16_signed[0].to_s(2)
# puts bm.first_16_signed[1].to_s(2)
# puts bm.first_16_signed[0].to_s(2).size
# puts bm.first_16_signed
# puts bm.first_16_signed[0].to_s(2)
# puts bm.first_16_signed[1].to_s(2)
# puts bm.first_16_signed[0].to_s(2).size
# puts "********************************************************************************"
#
# puts bm.big_e_23_16
# puts bm.big_e_23_16[0].to_s(2)
# puts bm.big_e_23_16[1].to_s(2)
# puts bm.big_e_23_16[0].to_s(2).size