class Gem::Version

# File lib/rubygems/version.rb, line 173
def self.correct?(version)
  nil_versions_are_discouraged! if version.nil?

  ANCHORED_VERSION_PATTERN.match?(version.to_s)
end

# File lib/rubygems/version.rb, line 187
def self.create(input)
  if self === input # check yourself before you wreck yourself
    input
  elsif input.nil?
    nil_versions_are_discouraged!

    nil
  else
    new input
  end
end

# File lib/rubygems/version.rb, line 221
def initialize(version)
  unless self.class.correct?(version)
    raise ArgumentError, "Malformed version number string #{version}"
  end

  # If version is an empty string convert it to 0
  version = 0 if version.is_a?(String) && /\A\s*\Z/.match?(version)

  @version = version.to_s

  # optimization to avoid allocation when given an integer, since we know
  # it's to_s won't have any spaces or dashes
  unless version.is_a?(Integer)
    @version = @version.strip
    @version.gsub!("-",".pre.")
  end
  @version = -@version
  @segments = nil
end

# File lib/rubygems/version.rb, line 209
def self.nil_versions_are_discouraged!
  unless Gem::Deprecate.skip
    warn "nil versions are discouraged and will be deprecated in Rubygems 4"
  end
end

# File lib/rubygems/version.rb, line 360
def <=>(other)
  return self <=> self.class.new(other) if (String === other) && self.class.correct?(other)

  return unless Gem::Version === other
  return 0 if @version == other.version || canonical_segments == other.canonical_segments

  lhsegments = canonical_segments
  rhsegments = other.canonical_segments

  lhsize = lhsegments.size
  rhsize = rhsegments.size
  limit  = (lhsize > rhsize ? lhsize : rhsize) - 1

  i = 0

  while i <= limit
    lhs = lhsegments[i] || 0
    rhs = rhsegments[i] || 0
    i += 1

    next      if lhs == rhs
    return -1 if String  === lhs && Numeric === rhs
    return  1 if Numeric === lhs && String  === rhs

    return lhs <=> rhs
  end

  0
end

# File lib/rubygems/version.rb, line 342
def approximate_recommendation
  segments = self.segments

  segments.pop    while segments.any? {|s| String === s }
  segments.pop    while segments.size > 2
  segments.push 0 while segments.size < 2

  recommendation = "~> #{segments.join(".")}"
  recommendation += ".a" if prerelease?
  recommendation
end

# File lib/rubygems/version.rb, line 247
def bump
  @@bump[self] ||= begin
                     segments = self.segments
                     segments.pop while segments.any? {|s| String === s }
                     segments.pop if segments.size > 1

                     segments[-1] = segments[-1].succ
                     self.class.new segments.join(".")
                   end
end

# File lib/rubygems/version.rb, line 391
def canonical_segments
  @canonical_segments ||= begin
    # remove trailing 0 segments, using dot or letter as anchor
    # may leave a trailing dot which will be ignored by partition_segments
    canonical_version = @version.sub(/(?<=[a-zA-Z.])[.0]+\z/, "")
    # remove 0 segments before the first letter in a prerelease version
    canonical_version.sub!(/(?<=\.|\A)[0.]+(?=[a-zA-Z])/, "") if prerelease?
    partition_segments(canonical_version)
  end
end

# File lib/rubygems/version.rb, line 262
def eql?(other)
  self.class === other && @version == other.version
end

# File lib/rubygems/version.rb, line 402
def freeze
  prerelease?
  _segments
  canonical_segments
  super
end

# File lib/rubygems/version.rb, line 282
def marshal_dump
  [@version]
end

# File lib/rubygems/version.rb, line 290
def marshal_load(array)
  string = array[0]
  raise TypeError, "wrong version string" unless string.is_a?(String)

  initialize string
end

# File lib/rubygems/version.rb, line 310
def prerelease?
  unless instance_variable_defined? :@prerelease
    @prerelease = /[a-zA-Z]/.match?(version)
  end
  @prerelease
end

# File lib/rubygems/version.rb, line 325
def release
  @@release[self] ||= if prerelease?
    segments = self.segments
    segments.pop while segments.any? {|s| String === s }
    self.class.new segments.join(".")
  else
    self
  end
end

# File lib/rubygems/version.rb, line 164
def version
  @version
end

# File lib/rubygems/version.rb, line 411
def _segments
  # segments is lazy so it can pick up version values that come from
  # old marshaled versions, which don't go through marshal_load.
  # since this version object is cached in @@all, its @segments should be frozen
  @segments ||= partition_segments(@version)
end

# File lib/rubygems/version.rb, line 418
def partition_segments(ver)
  ver.scan(/\d+|[a-z]+/i).map! do |s|
    /\A\d/.match?(s) ? s.to_i : -s
  end.freeze
end