Module: HexString

Included in:
String
Defined in:
lib/hex_string.rb

Overview

String extensions providing to_hex_string and to_byte_string. Requiring hex_string will automatically include HexString in the String class.

Instance Method Summary collapse

Instance Method Details

#to_byte_string ⇒ Object

Convert a human-readable hex string into binary data.

Assumes the target String is an ASCII, human readable sequence of hexadecimal tuples depicting a sequence of 8-bit byte values. Whitespace between tuples is allowed and will be removed before packing.

Returns a newly created string containing binary data -- the target string will not be modified.

Eg:

"68 65 6c 6c 6f".to_byte_string => "hello"



16
17
18
19
20
21
22
23
24
25
26
27
28
 
# File 'lib/hex_string.rb', line 16

def to_byte_string
  stripped = self.gsub(/\s+/,'')
  unless stripped.size % 2 == 0
    raise "Can't translate a string unless it has an even number of digits"
  end
   raise "Can't translate non-hex characters" if stripped =~ /[^0-9A-Fa-f]/
   res = [stripped].pack('H*')
   if RUBY_VERSION =~ /1.8/
     res
   else
     res.force_encoding("ascii-8bit")
   end
end

#to_hex_string(readable = true) ⇒ Object

Convert binary data into a human-readable hex string.

Whatever data is contained in the target string will be "exploded" into a sequence of hexadecimal tuples, one space between each tuple, for ease of debugging and reading.

Returns a newly created string containing the hex string -- the target binary string will not be modified.

Eg:

"hello world".to_hex_string => "68 65 6c 6c 6f 20 77 6f 72 6c 64"



40
41
42
43
44
45
46
47
 
# File 'lib/hex_string.rb', line 40

def to_hex_string(readable = true)
   unpacked = self.unpack('H*').first
   if readable
     unpacked.gsub(/(..)/,'\1 ').rstrip
   else
     unpacked
   end
end