Move random/formatter into non-gem stdlib

See ruby/ruby#5237

Author: headius

.gitignore

@@ -101,7 +101,6 @@ lib/ruby/stdlib/power_assert*
 lib/ruby/stdlib/prime*
 lib/ruby/stdlib/pstore*
 lib/ruby/stdlib/psych*
-lib/ruby/stdlib/random*
 lib/ruby/stdlib/rake*
 lib/ruby/stdlib/rdoc*
 lib/ruby/stdlib/readline*

lib/ruby/stdlib/random/formatter.rb

@@ -0,0 +1,372 @@
+# -*- coding: us-ascii -*-
+# frozen_string_literal: true
+
+# == \Random number formatter.
+#
+# Formats generated random numbers in many manners. When <tt>'random/formatter'</tt>
+# is required, several methods are added to empty core module <tt>Random::Formatter</tt>,
+# making them available as Random's instance and module methods.
+#
+# Standard library SecureRandom is also extended with the module, and the methods
+# described below are available as a module methods in it.
+#
+# === Examples
+#
+# Generate random hexadecimal strings:
+#
+#   require 'random/formatter'
+#
+#   prng = Random.new
+#   prng.hex(10) #=> "52750b30ffbc7de3b362"
+#   prng.hex(10) #=> "92b15d6c8dc4beb5f559"
+#   prng.hex(13) #=> "39b290146bea6ce975c37cfc23"
+#   # or just
+#   Random.hex #=> "1aed0c631e41be7f77365415541052ee"
+#
+# Generate random base64 strings:
+#
+#   prng.base64(10) #=> "EcmTPZwWRAozdA=="
+#   prng.base64(10) #=> "KO1nIU+p9DKxGg=="
+#   prng.base64(12) #=> "7kJSM/MzBJI+75j8"
+#   Random.base64(4) #=> "bsQ3fQ=="
+#
+# Generate random binary strings:
+#
+#   prng.random_bytes(10) #=> "\016\t{\370g\310pbr\301"
+#   prng.random_bytes(10) #=> "\323U\030TO\234\357\020\a\337"
+#   Random.random_bytes(6) #=> "\xA1\xE6Lr\xC43"
+#
+# Generate alphanumeric strings:
+#
+#   prng.alphanumeric(10) #=> "S8baxMJnPl"
+#   prng.alphanumeric(10) #=> "aOxAg8BAJe"
+#   Random.alphanumeric #=> "TmP9OsJHJLtaZYhP"
+#
+# Generate UUIDs:
+#
+#   prng.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
+#   prng.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
+#   Random.uuid #=> "f14e0271-de96-45cc-8911-8910292a42cd"
+#
+# All methods are available in the standard library SecureRandom, too:
+#
+#   SecureRandom.hex #=> "05b45376a30c67238eb93b16499e50cf"
+
+module Random::Formatter
+
+  # Generate 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'
+  #
+  #   Random.random_bytes #=> "\xD8\\\xE0\xF4\r\xB2\xFC*WM\xFF\x83\x18\xF45\xB6"
+  #   # or
+  #   prng = Random.new
+  #   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
+
+  # Generate 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'
+  #
+  #   Random.hex #=> "eb693ec8252cd630102fd0d0fb7c3485"
+  #   # or
+  #   prng = Random.new
+  #   prng.hex #=> "91dc3bfb4de5b11d029d376634589b61"
+  def hex(n=nil)
+    random_bytes(n).unpack1("H*")
+  end
+
+  # Generate 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'
+  #
+  #   Random.base64 #=> "/2BuBuLf3+WfSKyQbRcc/A=="
+  #   # or
+  #   prng = Random.new
+  #   prng.base64 #=> "6BbW0pxO0YENxn38HMUbcQ=="
+  #
+  # See RFC 3548 for the definition of base64.
+  def base64(n=nil)
+    [random_bytes(n)].pack("m0")
+  end
+
+  # Generate 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'
+  #
+  #   Random.urlsafe_base64 #=> "b4GOKm4pOYU_-BOXcrUGDg"
+  #   # or
+  #   prng = Random.new
+  #   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
+
+  # Generate a random v4 UUID (Universally Unique IDentifier).
+  #
+  #   require 'random/formatter'
+  #
+  #   Random.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
+  #   Random.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
+  #   # or
+  #   prng = Random.new
+  #   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 RFC9562[https://www.rfc-editor.org/rfc/rfc9562] for details of UUIDv4.
+  #
+  def uuid
+    ary = random_bytes(16)
+    ary.setbyte(6, (ary.getbyte(6) & 0x0f) | 0x40)
+    ary.setbyte(8, (ary.getbyte(8) & 0x3f) | 0x80)
+    ary.unpack("H8H4H4H4H12").join(?-)
+  end
+
+  alias uuid_v4 uuid
+
+  # Generate a random v7 UUID (Universally Unique IDentifier).
+  #
+  #   require 'random/formatter'
+  #
+  #   Random.uuid_v7 # => "0188d4c3-1311-7f96-85c7-242a7aa58f1e"
+  #   Random.uuid_v7 # => "0188d4c3-16fe-744f-86af-38fa04c62bb5"
+  #   Random.uuid_v7 # => "0188d4c3-1af8-764f-b049-c204ce0afa23"
+  #   Random.uuid_v7 # => "0188d4c3-1e74-7085-b14f-ef6415dc6f31"
+  #   #                    |<--sorted-->| |<----- random ---->|
+  #
+  #   # or
+  #   prng = Random.new
+  #   prng.uuid_v7 # => "0188ca51-5e72-7950-a11d-def7ff977c98"
+  #
+  # The version 7 UUID starts with the least significant 48 bits of a 64 bit
+  # Unix timestamp (milliseconds since the epoch) and fills the remaining bits
+  # with random data, excluding the version and variant bits.
+  #
+  # This allows version 7 UUIDs to be sorted by creation time.  Time ordered
+  # UUIDs can be used for better database index locality of newly inserted
+  # records, which may have a significant performance benefit compared to random
+  # data inserts.
+  #
+  # The result contains 74 random bits (9.25 random bytes).
+  #
+  # Note that this method cannot be made reproducible because its output
+  # includes not only random bits but also timestamp.
+  #
+  # See RFC9562[https://www.rfc-editor.org/rfc/rfc9562] for details of UUIDv7.
+  #
+  # ==== Monotonicity
+  #
+  # UUIDv7 has millisecond precision by default, so multiple UUIDs created
+  # within the same millisecond are not issued in monotonically increasing
+  # order.  To create UUIDs that are time-ordered with sub-millisecond
+  # precision, up to 12 bits of additional timestamp may added with
+  # +extra_timestamp_bits+.  The extra timestamp precision comes at the expense
+  # of random bits.  Setting <tt>extra_timestamp_bits: 12</tt> provides ~244ns
+  # of precision, but only 62 random bits (7.75 random bytes).
+  #
+  #   prng = Random.new
+  #   Array.new(4) { prng.uuid_v7(extra_timestamp_bits: 12) }
+  #   # =>
+  #   ["0188d4c7-13da-74f9-8b53-22a786ffdd5a",
+  #    "0188d4c7-13da-753b-83a5-7fb9b2afaeea",
+  #    "0188d4c7-13da-754a-88ea-ac0baeedd8db",
+  #    "0188d4c7-13da-7557-83e1-7cad9cda0d8d"]
+  #   # |<--- sorted --->| |<-- random --->|
+  #
+  #   Array.new(4) { prng.uuid_v7(extra_timestamp_bits: 8) }
+  #   # =>
+  #   ["0188d4c7-3333-7a95-850a-de6edb858f7e",
+  #    "0188d4c7-3333-7ae8-842e-bc3a8b7d0cf9",  # <- out of order
+  #    "0188d4c7-3333-7ae2-995a-9f135dc44ead",  # <- out of order
+  #    "0188d4c7-3333-7af9-87c3-8f612edac82e"]
+  #   # |<--- sorted -->||<---- random --->|
+  #
+  # Any rollbacks of the system clock will break monotonicity.  UUIDv7 is based
+  # on UTC, which excludes leap seconds and can rollback the clock.  To avoid
+  # this, the system clock can synchronize with an NTP server configured to use
+  # a "leap smear" approach.  NTP or PTP will also be needed to synchronize
+  # across distributed nodes.
+  #
+  # Counters and other mechanisms for stronger guarantees of monotonicity are
+  # not implemented.  Applications with stricter requirements should follow
+  # {Section 6.2}[https://www.rfc-editor.org/rfc/rfc9562.html#name-monotonicity-and-counters]
+  # of the specification.
+  #
+  def uuid_v7(extra_timestamp_bits: 0)
+    case (extra_timestamp_bits = Integer(extra_timestamp_bits))
+    when 0 # min timestamp precision
+      ms = Process.clock_gettime(Process::CLOCK_REALTIME, :millisecond)
+      rand = random_bytes(10)
+      rand.setbyte(0, rand.getbyte(0) & 0x0f | 0x70) # version
+      rand.setbyte(2, rand.getbyte(2) & 0x3f | 0x80) # variant
+      "%08x-%04x-%s" % [
+        (ms & 0x0000_ffff_ffff_0000) >> 16,
+        (ms & 0x0000_0000_0000_ffff),
+        rand.unpack("H4H4H12").join("-")
+      ]
+
+    when 12 # max timestamp precision
+      ms, ns = Process.clock_gettime(Process::CLOCK_REALTIME, :nanosecond)
+        .divmod(1_000_000)
+      extra_bits = ns * 4096 / 1_000_000
+      rand = random_bytes(8)
+      rand.setbyte(0, rand.getbyte(0) & 0x3f | 0x80) # variant
+      "%08x-%04x-7%03x-%s" % [
+        (ms & 0x0000_ffff_ffff_0000) >> 16,
+        (ms & 0x0000_0000_0000_ffff),
+        extra_bits,
+        rand.unpack("H4H12").join("-")
+      ]
+
+    when (0..12) # the generic version is slower than the special cases above
+      rand_a, rand_b1, rand_b2, rand_b3 = random_bytes(10).unpack("nnnN")
+      rand_mask_bits = 12 - extra_timestamp_bits
+      ms, ns = Process.clock_gettime(Process::CLOCK_REALTIME, :nanosecond)
+        .divmod(1_000_000)
+      "%08x-%04x-%04x-%04x-%04x%08x" % [
+        (ms & 0x0000_ffff_ffff_0000) >> 16,
+        (ms & 0x0000_0000_0000_ffff),
+        0x7000 |
+          ((ns * (1 << extra_timestamp_bits) / 1_000_000) << rand_mask_bits) |
+          rand_a & ((1 << rand_mask_bits) - 1),
+        0x8000 | (rand_b1 & 0x3fff),
+        rand_b2,
+        rand_b3
+      ]
+
+    else
+      raise ArgumentError, "extra_timestamp_bits must be in 0..12"
+    end
+  end
+
+  # Internal interface to Random; Generate random data _n_ bytes.
+  private def gen_random(n)
+    self.bytes(n)
+  end
+
+  # Generate 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
+
+  # The default character list for #alphanumeric.
+  ALPHANUMERIC = [*'A'..'Z', *'a'..'z', *'0'..'9']
+
+  # Generate a random alphanumeric string.
+  #
+  # The argument _n_ specifies the length, in characters, of the alphanumeric
+  # string to be generated.
+  # The argument _chars_ specifies the character list which the result is
+  # consist of.
+  #
+  # 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, unless _chars_ is specified.
+  #
+  #   require 'random/formatter'
+  #
+  #   Random.alphanumeric     #=> "2BuBuLf3WfSKyQbR"
+  #   # or
+  #   prng = Random.new
+  #   prng.alphanumeric(10) #=> "i6K93NdqiH"
+  #
+  #   Random.alphanumeric(4, chars: [*"0".."9"]) #=> "2952"
+  #   # or
+  #   prng = Random.new
+  #   prng.alphanumeric(10, chars: [*"!".."/"]) #=> ",.,++%/''."
+  def alphanumeric(n = nil, chars: ALPHANUMERIC)
+    n = 16 if n.nil?
+    choose(chars, n)
+  end
+end