module Random::Formatter

Random number formatter. ↑

Formats generated random numbers in many manners.

Examples ↑

Generate random hexadecimal strings:

require 'random/formatter'

prng.hex(10) #=> "52750b30ffbc7de3b362"
prng.hex(10) #=> "92b15d6c8dc4beb5f559"
prng.hex(13) #=> "39b290146bea6ce975c37cfc23"

Generate random base64 strings:

prng.base64(10) #=> "EcmTPZwWRAozdA=="
prng.base64(10) #=> "KO1nIU+p9DKxGg=="
prng.base64(12) #=> "7kJSM/MzBJI+75j8"

Generate random binary strings:

prng.random_bytes(10) #=> "\016\t{\370g\310pbr\301"
prng.random_bytes(10) #=> "\323U\030TO\234\357\020\a\337"

Generate alphanumeric strings:

prng.alphanumeric(10) #=> "S8baxMJnPl"
prng.alphanumeric(10) #=> "aOxAg8BAJe"

Generate UUIDs:

prng.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
prng.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"

Generate a random number in the given range as Random does

prng.random_number       #=> 0.5816771641321361
prng.random_number(1000) #=> 485
prng.random_number(1..6) #=> 3
prng.rand                #=> 0.5816771641321361
prng.rand(1000)          #=> 485
prng.rand(1..6)          #=> 3

Constants

ALPHANUMERIC

Public Instance Methods

alphanumeric(n=nil) click to toggle source

Random::Formatter#alphanumeric generates a random alphanumeric string.

The argument n specifies the length, in characters, of the alphanumeric string to be generated.

If n is not specified or is nil, 16 is assumed. It may be larger in the future.

The result may contain A-Z, a-z and 0-9.

require 'random/formatter'

prng.alphanumeric     #=> "2BuBuLf3WfSKyQbR"
prng.alphanumeric(10) #=> "i6K93NdqiH"

# File lib/random/formatter.rb, line 212
def alphanumeric(n=nil)
  n = 16 if n.nil?
  choose(ALPHANUMERIC, n)
end
base64(n=nil) click to toggle source

Random::Formatter#base64 generates a random base64 string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the result string is about 4/3 of n.

If n is not specified or is nil, 16 is assumed. It may be larger in the future.

The result may contain A-Z, a-z, 0-9, “+”, “/” and “=”.

require 'random/formatter'

prng.base64 #=> "/2BuBuLf3+WfSKyQbRcc/A=="
prng.base64 #=> "6BbW0pxO0YENxn38HMUbcQ=="

See RFC 3548 for the definition of base64.

# File lib/random/formatter.rb, line 92
def base64(n=nil)
  [random_bytes(n)].pack("m0")
end
hex(n=nil) click to toggle source

Random::Formatter#hex generates a random hexadecimal string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the resulting hexadecimal string is twice of n.

If n is not specified or is nil, 16 is assumed. It may be larger in the future.

The result may contain 0-9 and a-f.

require 'random/formatter'

prng.hex #=> "eb693ec8252cd630102fd0d0fb7c3485"
prng.hex #=> "91dc3bfb4de5b11d029d376634589b61"

# File lib/random/formatter.rb, line 72
def hex(n=nil)
  random_bytes(n).unpack1("H*")
end
rand → float
rand(max) → number
rand(range) → number

Generates formatted random number from raw random bytes. See Random#rand.

Alias for: random_number
random_bytes(n=nil) click to toggle source

Random::Formatter#random_bytes generates a random binary string.

The argument n specifies the length of the result string.

If n is not specified or is nil, 16 is assumed. It may be larger in future.

The result may contain any byte: “x00” - “xff”.

require 'random/formatter'

prng.random_bytes #=> "\xD8\\\xE0\xF4\r\xB2\xFC*WM\xFF\x83\x18\xF45\xB6"
prng.random_bytes #=> "m\xDC\xFC/\a\x00Uf\xB2\xB2P\xBD\xFF6S\x97"

# File lib/random/formatter.rb, line 53
def random_bytes(n=nil)
  n = n ? n.to_int : 16
  gen_random(n)
end
random_number(range) -> number click to toggle source

Generates formatted random number from raw random bytes. See Random#rand.

static VALUE
rand_random_number(int argc, VALUE *argv, VALUE obj)
{
    rb_random_t *rnd = try_get_rnd(obj);
    VALUE v = rand_random(argc, argv, obj, rnd);
    if (NIL_P(v)) v = rand_random(0, 0, obj, rnd);
    else if (!v) invalid_argument(argv[0]);
    return v;
}
Also aliased as: rand
urlsafe_base64(n=nil, padding=false) click to toggle source

Random::Formatter#urlsafe_base64 generates a random URL-safe base64 string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the result string is about 4/3 of n.

If n is not specified or is nil, 16 is assumed. It may be larger in the future.

The boolean argument padding specifies the padding. If it is false or nil, padding is not generated. Otherwise padding is generated. By default, padding is not generated because “=” may be used as a URL delimiter.

The result may contain A-Z, a-z, 0-9, “-” and “_”. “=” is also used if padding is true.

require 'random/formatter'

prng.urlsafe_base64 #=> "b4GOKm4pOYU_-BOXcrUGDg"
prng.urlsafe_base64 #=> "UZLdOkzop70Ddx-IJR0ABg"

prng.urlsafe_base64(nil, true) #=> "i0XQ-7gglIsHGV2_BNPrdQ=="
prng.urlsafe_base64(nil, true) #=> "-M8rLhr7JEpJlqFGUMmOxg=="

See RFC 3548 for the definition of URL-safe base64.

# File lib/random/formatter.rb, line 121
def urlsafe_base64(n=nil, padding=false)
  s = [random_bytes(n)].pack("m0")
  s.tr!("+/", "-_")
  s.delete!("=") unless padding
  s
end
uuid() click to toggle source

Random::Formatter#uuid generates a random v4 UUID (Universally Unique IDentifier).

require 'random/formatter'

prng.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
prng.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
prng.uuid #=> "62936e70-1815-439b-bf89-8492855a7e6b"

The version 4 UUID is purely random (except the version). It doesn’t contain meaningful information such as MAC addresses, timestamps, etc.

The result contains 122 random bits (15.25 random bytes).

See RFC 4122 for details of UUID.

# File lib/random/formatter.rb, line 143
def uuid
  ary = random_bytes(16).unpack("NnnnnN")
  ary[2] = (ary[2] & 0x0fff) | 0x4000
  ary[3] = (ary[3] & 0x3fff) | 0x8000
  "%08x-%04x-%04x-%04x-%04x%08x" % ary
end

Private Instance Methods

choose(source, n) click to toggle source

Random::Formatter#choose generates a string that randomly draws from a source array of characters.

The argument source specifies the array of characters from which to generate the string. The argument n specifies the length, in characters, of the string to be generated.

The result may contain whatever characters are in the source array.

require 'random/formatter'

prng.choose([*'l'..'r'], 16) #=> "lmrqpoonmmlqlron"
prng.choose([*'0'..'9'], 5)  #=> "27309"

# File lib/random/formatter.rb, line 168
        def choose(source, n)
  size = source.size
  m = 1
  limit = size
  while limit * size <= 0x100000000
    limit *= size
    m += 1
  end
  result = ''.dup
  while m <= n
    rs = random_number(limit)
    is = rs.digits(size)
    (m-is.length).times { is << 0 }
    result << source.values_at(*is).join('')
    n -= m
  end
  if 0 < n
    rs = random_number(limit)
    is = rs.digits(size)
    if is.length < n
      (n-is.length).times { is << 0 }
    else
      is.pop while n < is.length
    end
    result.concat source.values_at(*is).join('')
  end
  result
end
gen_random(n) click to toggle source 
# File lib/random/formatter.rb, line 150
        def gen_random(n)
  self.bytes(n)
end