Module: MIDIMessage::TypeConversion

Extended by:
TypeConversion
Included in:
TypeConversion
Defined in:
lib/midi-message/type_conversion.rb

Overview

Helper for converting nibbles and bytes

Instance Method Summary collapse

Instance Method Details

#hex_chars_to_numeric_byte_array(nibbles) ⇒ Array<Fixnum] An array of numeric bytes eg [0x90, 0x40]

Convert an array of hex nibbles to an array of numeric bytes eg [“9”, “0”, “4”, “0”] to [0x90, 0x40]

Parameters:

  • An (Array<String>) —

    array of hex nibbles eg [“9”, “0”, “4”, “0”]

Returns:

  • (Array<Fixnum] An array of numeric bytes eg [0x90, 0x40]) —

    Array<Fixnum] An array of numeric bytes eg [0x90, 0x40]



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# File 'lib/midi-message/type_conversion.rb', line 13

def hex_chars_to_numeric_byte_array(nibbles)
  nibbles = nibbles.dup # Don't mess with the input
  # get rid of last nibble if there's an odd number
  # it will be processed later anyway
  nibbles.slice!(nibbles.length-2, 1) if nibbles.length.odd?
  bytes = []
  while !(nibs = nibbles.slice!(0,2)).empty?
    byte = (nibs[0].hex << 4) + nibs[1].hex
    bytes << byte
  end
  bytes
end

#hex_str_to_hex_chars(string) ⇒ Array<String>

Convert a string of hex digits to an array of nibbles eg. “904040” to [“9”, “0”, “4”, “0”, “4”, “0”]

Parameters:

  • string (String) —

    A string representing hex digits eg “904040”

Returns:

  • (Array<String>) —

    An array of hex nibble chars eg [“9”, “0”, “4”, “0”, “4”, “0”]



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# File 'lib/midi-message/type_conversion.rb', line 43

def hex_str_to_hex_chars(string)
  string.split(//)    
end

#hex_string_to_numeric_byte_array(string) ⇒ Array<Fixnum>

Convert byte string to an array of numeric bytes eg. “904040” to [0x90, 0x40, 0x40]

Parameters:

  • string (String) —

    A string representing hex digits eg “904040”

Returns:

  • (Array<Fixnum>) —

    An array of numeric bytes eg [0x90, 0x40, 0x40]



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# File 'lib/midi-message/type_conversion.rb', line 30

def hex_string_to_numeric_byte_array(string)
  string = string.dup
  bytes = []
  until string.length == 0
    bytes << string.slice!(0, 2).hex
  end
  bytes
end

#numeric_byte_array_to_hex_string(bytes) ⇒ String

Convert an array of numeric bytes to a string of hex digits eg. [0x90, 0x40, 0x40] to “904040”

Parameters:

  • bytes (Array<Fixnum>) —

    An array of numeric bytes eg [0x90, 0x40, 0x40]

Returns:

  • (String) —

    A string representing hex digits eg “904040”



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# File 'lib/midi-message/type_conversion.rb', line 51

def numeric_byte_array_to_hex_string(bytes)
  string_bytes = bytes.map do |byte| 
    string = byte.to_s(16)
    string = "0#{string}" if string.length == 1
    string
  end
  string_bytes.join.upcase
end

#numeric_byte_to_hex_chars(num) ⇒ Array<String>

Convert a numeric byte to hex chars eg 0x90 to [“9”, “0”]

Parameters:

  • num (Fixnum) —

    A numeric byte eg 0x90

Returns:

  • (Array<String>) —

    An array of hex nibble chars eg [“9”, “0”]



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# File 'lib/midi-message/type_conversion.rb', line 64

def numeric_byte_to_hex_chars(num)
  nibbles = numeric_byte_to_nibbles(num)
  nibbles.map { |n| n.to_s(16) }      
end

#numeric_byte_to_nibbles(num) ⇒ Array<Fixnum>

Convert a numeric byte to nibbles eg 0x90 to [0x9, 0x0]

Parameters:

  • num (Fixnum) —

    A numeric byte eg 0x90

Returns:

  • (Array<Fixnum>) —

    An array of nibbles eg [0x9, 0x0]



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# File 'lib/midi-message/type_conversion.rb', line 73

def numeric_byte_to_nibbles(num)
  [((num & 0xF0) >> 4), (num & 0x0F)]
end