Class: Array

Inherits:
Object
  • Object
show all
Defined in:
lib/rmodbus/ext.rb

Instance Method Summary collapse

Instance Method Details

#byteswap ⇒ Object Also known as: wordswap

Swap every pair of elements



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# File 'lib/rmodbus/ext.rb', line 36

def byteswap
  even_elements_check
  each_slice(2).flat_map(&:reverse)
end

#from_32f ⇒ Object

Given an array of 32-bit floats, turn it into an array of 16-bit unsigned integers, doubling the size.



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# File 'lib/rmodbus/ext.rb', line 55

def from_32f
  pack("g*").unpack("n*")
end

#from_32i ⇒ Object

Given an array of 32bit signed integers, turn it into an array of 16 bit unsigned integers, doubling the size



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# File 'lib/rmodbus/ext.rb', line 79

def from_32i
  pack("l>*").unpack("n*")
end

#from_32u ⇒ Object

Given an array of 32bit unsigned integers, turn it into an array of 16 bit unsigned integers, doubling the size



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# File 'lib/rmodbus/ext.rb', line 74

def from_32u
  pack("N*").unpack("n*")
end

#pack_bits ⇒ Object

pack an array of bits into a string of bytes, as the ModBus protocol dictates for coils



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# File 'lib/rmodbus/ext.rb', line 85

def pack_bits
  # pack each slice of 8 bits per byte,
  # forward order (bits 0-7 in byte 0, 8-15 in byte 1, etc.)
  # non-multiples of 8 are just 0-padded
  each_slice(8).map do |slice|
    byte = 0
    # within each byte, bit 0 is the LSB,
    # and bit 7 is the MSB
    slice.reverse_each do |bit|
      byte <<= 1
      byte |= 1 if bit.positive?
    end
    byte
  end.pack("C*")
end

#to_16i ⇒ Object

Given an array of 16-bit unsigned integers, turn it into an array of 16-bit signed integers.



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# File 'lib/rmodbus/ext.rb', line 43

def to_16i
  pack("n*").unpack("s>*")
end

#to_32f ⇒ Object

Given an array of 16-bit unsigned integers, turn it into an array of 32-bit floats, halving the size. The pairs of 16-bit elements should be in big endian order.



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# File 'lib/rmodbus/ext.rb', line 49

def to_32f
  even_elements_check
  pack("n*").unpack("g*")
end

#to_32i ⇒ Object

Given an array of 16-bit unsigned integers, turn it into 32-bit signed integers, halving the size. The pairs of 16-bit elements should be in big endian order.



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# File 'lib/rmodbus/ext.rb', line 68

def to_32i
  even_elements_check
  pack("n*").unpack("l>*")
end

#to_32u ⇒ Object

Given an array of 16-bit unsigned integers, turn it into 32-bit unsigned integers, halving the size. The pairs of 16-bit elements should be in big endian order.



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# File 'lib/rmodbus/ext.rb', line 61

def to_32u
  even_elements_check
  pack("n*").unpack("N*")
end