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Diffstat (limited to 'lib/random/formatter.rb')
| -rw-r--r-- | lib/random/formatter.rb | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/lib/random/formatter.rb b/lib/random/formatter.rb new file mode 100644 index 0000000000..c48886f9e0 --- /dev/null +++ b/lib/random/formatter.rb @@ -0,0 +1,215 @@ +# -*- coding: us-ascii -*- +# frozen_string_literal: true + +# == Random number formatter. +# +# === 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" + +module Random::Formatter + + # 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" + def random_bytes(n=nil) + n = n ? n.to_int : 16 + gen_random(n) + end + + # 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" + def hex(n=nil) + random_bytes(n).unpack("H*")[0] + end + + # 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. + def base64(n=nil) + [random_bytes(n)].pack("m0") + end + + # 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. + def urlsafe_base64(n=nil, padding=false) + s = [random_bytes(n)].pack("m0") + s.tr!("+/", "-_") + s.delete!("=") unless padding + s + end + + # 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. + # + 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 def gen_random(n) + self.bytes(n) + end + + # 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" + private 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 + + ALPHANUMERIC = [*'A'..'Z', *'a'..'z', *'0'..'9'] + # 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" + def alphanumeric(n=nil) + n = 16 if n.nil? + choose(ALPHANUMERIC, n) + end +end |