[ruby/securerandom] Split Random::Formatter from SecureRandom [Feature #18190]

https://github.com/ruby/securerandom/commit/1e57277b9e

2 files changed, 219 insertions, 229 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
diff --git a/lib/securerandom.rb b/lib/securerandom.rb
index 323d4af3b7..9cbf4ea789 100644
--- a/lib/securerandom.rb
+++ b/lib/securerandom.rb
@@ -1,6 +1,8 @@
 # -*- coding: us-ascii -*-
 # frozen_string_literal: true
 
+require 'random/formatter'
+
 # == Secure random number generator interface.
 #
 # This library is an interface to secure random number generators which are
@@ -33,37 +35,8 @@
 # These methods are usable as class methods of SecureRandom such as
 # +SecureRandom.hex+.
 #
-# === Examples
-#
-# Generate random hexadecimal strings:
-#
-#   require 'securerandom'
-#
-#   SecureRandom.hex(10) #=> "52750b30ffbc7de3b362"
-#   SecureRandom.hex(10) #=> "92b15d6c8dc4beb5f559"
-#   SecureRandom.hex(13) #=> "39b290146bea6ce975c37cfc23"
-#
-# Generate random base64 strings:
-#
-#   SecureRandom.base64(10) #=> "EcmTPZwWRAozdA=="
-#   SecureRandom.base64(10) #=> "KO1nIU+p9DKxGg=="
-#   SecureRandom.base64(12) #=> "7kJSM/MzBJI+75j8"
-#
-# Generate random binary strings:
-#
-#   SecureRandom.random_bytes(10) #=> "\016\t{\370g\310pbr\301"
-#   SecureRandom.random_bytes(10) #=> "\323U\030TO\234\357\020\a\337"
-#
-# Generate alphanumeric strings:
-#
-#   SecureRandom.alphanumeric(10) #=> "S8baxMJnPl"
-#   SecureRandom.alphanumeric(10) #=> "aOxAg8BAJe"
-#
-# Generate UUIDs:
-#
-#   SecureRandom.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
-#   SecureRandom.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
-#
+# If a secure random number generator is not available,
+# +NotImplementedError+ is raised.
 
 module SecureRandom
   class << self
@@ -116,202 +89,4 @@ module SecureRandom
   end
 end
 
-module Random::Formatter
-
-  # SecureRandom.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 'securerandom'
-  #
-  #   SecureRandom.random_bytes #=> "\xD8\\\xE0\xF4\r\xB2\xFC*WM\xFF\x83\x18\xF45\xB6"
-  #   SecureRandom.random_bytes #=> "m\xDC\xFC/\a\x00Uf\xB2\xB2P\xBD\xFF6S\x97"
-  #
-  # If a secure random number generator is not available,
-  # +NotImplementedError+ is raised.
-  def random_bytes(n=nil)
-    n = n ? n.to_int : 16
-    gen_random(n)
-  end
-
-  # SecureRandom.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 'securerandom'
-  #
-  #   SecureRandom.hex #=> "eb693ec8252cd630102fd0d0fb7c3485"
-  #   SecureRandom.hex #=> "91dc3bfb4de5b11d029d376634589b61"
-  #
-  # If a secure random number generator is not available,
-  # +NotImplementedError+ is raised.
-  def hex(n=nil)
-    random_bytes(n).unpack("H*")[0]
-  end
-
-  # SecureRandom.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 'securerandom'
-  #
-  #   SecureRandom.base64 #=> "/2BuBuLf3+WfSKyQbRcc/A=="
-  #   SecureRandom.base64 #=> "6BbW0pxO0YENxn38HMUbcQ=="
-  #
-  # If a secure random number generator is not available,
-  # +NotImplementedError+ is raised.
-  #
-  # See RFC 3548 for the definition of base64.
-  def base64(n=nil)
-    [random_bytes(n)].pack("m0")
-  end
-
-  # SecureRandom.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 'securerandom'
-  #
-  #   SecureRandom.urlsafe_base64 #=> "b4GOKm4pOYU_-BOXcrUGDg"
-  #   SecureRandom.urlsafe_base64 #=> "UZLdOkzop70Ddx-IJR0ABg"
-  #
-  #   SecureRandom.urlsafe_base64(nil, true) #=> "i0XQ-7gglIsHGV2_BNPrdQ=="
-  #   SecureRandom.urlsafe_base64(nil, true) #=> "-M8rLhr7JEpJlqFGUMmOxg=="
-  #
-  # If a secure random number generator is not available,
-  # +NotImplementedError+ is raised.
-  #
-  # 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
-
-  # SecureRandom.uuid generates a random v4 UUID (Universally Unique IDentifier).
-  #
-  #   require 'securerandom'
-  #
-  #   SecureRandom.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
-  #   SecureRandom.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
-  #   SecureRandom.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
-
-  # SecureRandom.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 'securerandom'
-  #
-  #   SecureRandom.choose([*'l'..'r'], 16) #=> "lmrqpoonmmlqlron"
-  #   SecureRandom.choose([*'0'..'9'], 5)  #=> "27309"
-  #
-  # If a secure random number generator is not available,
-  # +NotImplementedError+ is raised.
-  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']
-  # SecureRandom.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 'securerandom'
-  #
-  #   SecureRandom.alphanumeric     #=> "2BuBuLf3WfSKyQbR"
-  #   SecureRandom.alphanumeric(10) #=> "i6K93NdqiH"
-  #
-  # If a secure random number generator is not available,
-  # +NotImplementedError+ is raised.
-  def alphanumeric(n=nil)
-    n = 16 if n.nil?
-    choose(ALPHANUMERIC, n)
-  end
-end
-
 SecureRandom.extend(Random::Formatter)