Class: HexHelper

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

Overview

hexhelper.rb Created November, 2012 By Ron Bowes

See: LICENSE.md

This is a simple utility class that converts an arbitrary binary string into a user-readable string.

Constant Summary collapse

BYTE_NUMBER_LENGTH = 
8
SPACES_BEFORE_HEX = 
2
SPACES_BEFORE_ASCII = 
2
LINE_LENGTH = 
16

Class Method Summary collapse

Class Method Details

.to_s(data, indent: 0, offset: nil) ⇒ Object

Convert the arbitrary binary data, ‘data’, into a user-readable string.



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# File 'lib/hexhelper.rb', line 20

def self.to_s(data, indent: 0, offset: nil)
  length = data.length
  out = (' ' * indent)

  0.upto(length - 1) do |i|
    # This section encodes all the hex lines, including the final partial line
    if((i % LINE_LENGTH) == 0)
      if(i != 0)
        # Subtract one from the indent because we print a space surrounding
        # the actual hex number
        out = out + "\n" + (' ' * indent)
      end
      # Minus 1, so we can potentially replace the last one with a current-
      # place marker
      out = out + ("%0#{BYTE_NUMBER_LENGTH}x" % i) + " " * (SPACES_BEFORE_HEX - 1)
      if(offset && (i == offset))
        out = out + '<'
      else
        out = out + ' '
      end
    end

    out = out + ("%02x" % data[i].ord)
    # Always put a '>' immediately after the highlighted offset
    if(i == offset)
      out = out + '>'
    # Put a '>' after the value before the chosen offset, unless we're at
    # the end of a line or the absolute end
    elsif((i + 1 == offset) && (((i + 1) % LINE_LENGTH) != 0) && ((i + 1) % length) != 0)
      out = out + '<'
    else
      out = out + ' '
    end

    if(((i + 1) % LINE_LENGTH) == 0)
      out = out + (" " * SPACES_BEFORE_ASCII)
      LINE_LENGTH.step(1, -1) do |j|
        out = out + ("%c" % ((data[i + 1 - j].ord > 0x20 && data[i + 1 - j].ord < 0x80) ? data[i + 1 - j].ord : ?.))
      end
    end

  end

  # This encodes the partial line of ascii, plus the spaces before
  if((length % LINE_LENGTH) != 0)
    # Add extra spaces between the hex and the ascii
    (length % LINE_LENGTH).upto(LINE_LENGTH - 1) do |i|
      out = out + ('   ') # The width of a hex character and a space
    end
    out = out + (' ' * SPACES_BEFORE_ASCII)

    # Add the final line of characters
    (length - (length % LINE_LENGTH)).upto(length - 1) do |i|
      out = out + ("%c" % ((data[i].ord > 0x20 && data[i].ord < 0x80) ? data[i].ord : ?.))
    end
  end

  return out
end