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ruby--ruby/lib/set.rb
knu 0fcac8f1a3 Avoid use of self.class.new(self) in Set#collect! 
That prevents infinite recursion when a subclass of Set uses
`collect!` in its constructor.

This should fix [Bug #12437].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60317 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
2017-10-21 17:03:40 +00:00

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#--
# frozen_string_literal: true
#
# set.rb - defines the Set class
#++
# Copyright (c) 2002-2016 Akinori MUSHA <knu@iDaemons.org>
#
# Documentation by Akinori MUSHA and Gavin Sinclair.
#
# All rights reserved. You can redistribute and/or modify it under the same
# terms as Ruby.
#
# $Id$
#
# == Overview
#
# This library provides the Set class, which deals with a collection
# of unordered values with no duplicates. It is a hybrid of Array's
# intuitive inter-operation facilities and Hash's fast lookup. If you
# need to keep values sorted in some order, use the SortedSet class.
#
# The method +to_set+ is added to Enumerable for convenience.
#
# See the Set and SortedSet documentation for examples of usage.
#
# Set implements a collection of unordered values with no duplicates.
# This is a hybrid of Array's intuitive inter-operation facilities and
# Hash's fast lookup.
#
# Set is easy to use with Enumerable objects (implementing +each+).
# Most of the initializer methods and binary operators accept generic
# Enumerable objects besides sets and arrays. An Enumerable object
# can be converted to Set using the +to_set+ method.
#
# Set uses Hash as storage, so you must note the following points:
#
# * Equality of elements is determined according to Object#eql? and
# Object#hash. Use Set#compare_by_identity to make a set compare
# its elements by their identity.
# * Set assumes that the identity of each element does not change
# while it is stored. Modifying an element of a set will render the
# set to an unreliable state.
# * When a string is to be stored, a frozen copy of the string is
# stored instead unless the original string is already frozen.
#
# == Comparison
#
# The comparison operators <, >, <= and >= are implemented as
# shorthand for the {proper_,}{subset?,superset?} methods. However,
# the <=> operator is intentionally left out because not every pair of
# sets is comparable. ({x,y} vs. {x,z} for example)
#
# == Example
#
# require 'set'
# s1 = Set.new [1, 2] # -> #<Set: {1, 2}>
# s2 = [1, 2].to_set # -> #<Set: {1, 2}>
# s1 == s2 # -> true
# s1.add("foo") # -> #<Set: {1, 2, "foo"}>
# s1.merge([2, 6]) # -> #<Set: {1, 2, "foo", 6}>
# s1.subset? s2 # -> false
# s2.subset? s1 # -> true
#
# == Contact
#
# - Akinori MUSHA <knu@iDaemons.org> (current maintainer)
#
class Set
include Enumerable
# Creates a new set containing the given objects.
def self.[](*ary)
new(ary)
end
# Creates a new set containing the elements of the given enumerable
# object.
#
# If a block is given, the elements of enum are preprocessed by the
# given block.
def initialize(enum = nil, &block) # :yields: o
@hash ||= Hash.new(false)
enum.nil? and return
if block
do_with_enum(enum) { |o| add(block[o]) }
else
merge(enum)
end
end
# Makes the set compare its elements by their identity and returns
# self. This method may not be supported by all subclasses of Set.
def compare_by_identity
if @hash.respond_to?(:compare_by_identity)
@hash.compare_by_identity
self
else
raise NotImplementedError, "#{self.class.name}\##{__method__} is not implemented"
end
end
# Returns true if the set will compare its elements by their
# identity. Also see Set#compare_by_identity.
def compare_by_identity?
@hash.respond_to?(:compare_by_identity?) && @hash.compare_by_identity?
end
def do_with_enum(enum, &block) # :nodoc:
if enum.respond_to?(:each_entry)
enum.each_entry(&block) if block
elsif enum.respond_to?(:each)
enum.each(&block) if block
else
raise ArgumentError, "value must be enumerable"
end
end
private :do_with_enum
# Dup internal hash.
def initialize_dup(orig)
super
@hash = orig.instance_variable_get(:@hash).dup
end
# Clone internal hash.
def initialize_clone(orig)
super
@hash = orig.instance_variable_get(:@hash).clone
end
def freeze # :nodoc:
@hash.freeze
super
end
def taint # :nodoc:
@hash.taint
super
end
def untaint # :nodoc:
@hash.untaint
super
end
# Returns the number of elements.
def size
@hash.size
end
alias length size
# Returns true if the set contains no elements.
def empty?
@hash.empty?
end
# Removes all elements and returns self.
def clear
@hash.clear
self
end
# Replaces the contents of the set with the contents of the given
# enumerable object and returns self.
def replace(enum)
if enum.instance_of?(self.class)
@hash.replace(enum.instance_variable_get(:@hash))
self
else
do_with_enum(enum) # make sure enum is enumerable before calling clear
clear
merge(enum)
end
end
# Converts the set to an array. The order of elements is uncertain.
def to_a
@hash.keys
end
# Returns self if no arguments are given. Otherwise, converts the
# set to another with klass.new(self, *args, &block).
#
# In subclasses, returns klass.new(self, *args, &block) unless
# overridden.
def to_set(klass = Set, *args, &block)
return self if instance_of?(Set) && klass == Set && block.nil? && args.empty?
klass.new(self, *args, &block)
end
def flatten_merge(set, seen = Set.new) # :nodoc:
set.each { |e|
if e.is_a?(Set)
if seen.include?(e_id = e.object_id)
raise ArgumentError, "tried to flatten recursive Set"
end
seen.add(e_id)
flatten_merge(e, seen)
seen.delete(e_id)
else
add(e)
end
}
self
end
protected :flatten_merge
# Returns a new set that is a copy of the set, flattening each
# containing set recursively.
def flatten
self.class.new.flatten_merge(self)
end
# Equivalent to Set#flatten, but replaces the receiver with the
# result in place. Returns nil if no modifications were made.
def flatten!
replace(flatten()) if any? { |e| e.is_a?(Set) }
end
# Returns true if the set contains the given object.
#
# Note that <code>include?</code> and <code>member?</code> do not test member
# equality using <code>==</code> as do other Enumerables.
#
# See also Enumerable#include?
def include?(o)
@hash[o]
end
alias member? include?
# Returns true if the set is a superset of the given set.
def superset?(set)
case
when set.instance_of?(self.class) && @hash.respond_to?(:>=)
@hash >= set.instance_variable_get(:@hash)
when set.is_a?(Set)
size >= set.size && set.all? { |o| include?(o) }
else
raise ArgumentError, "value must be a set"
end
end
alias >= superset?
# Returns true if the set is a proper superset of the given set.
def proper_superset?(set)
case
when set.instance_of?(self.class) && @hash.respond_to?(:>)
@hash > set.instance_variable_get(:@hash)
when set.is_a?(Set)
size > set.size && set.all? { |o| include?(o) }
else
raise ArgumentError, "value must be a set"
end
end
alias > proper_superset?
# Returns true if the set is a subset of the given set.
def subset?(set)
case
when set.instance_of?(self.class) && @hash.respond_to?(:<=)
@hash <= set.instance_variable_get(:@hash)
when set.is_a?(Set)
size <= set.size && all? { |o| set.include?(o) }
else
raise ArgumentError, "value must be a set"
end
end
alias <= subset?
# Returns true if the set is a proper subset of the given set.
def proper_subset?(set)
case
when set.instance_of?(self.class) && @hash.respond_to?(:<)
@hash < set.instance_variable_get(:@hash)
when set.is_a?(Set)
size < set.size && all? { |o| set.include?(o) }
else
raise ArgumentError, "value must be a set"
end
end
alias < proper_subset?
# Returns true if the set and the given set have at least one
# element in common.
#
# e.g.:
#
# require 'set'
# Set[1, 2, 3].intersect? Set[4, 5] # => false
# Set[1, 2, 3].intersect? Set[3, 4] # => true
def intersect?(set)
set.is_a?(Set) or raise ArgumentError, "value must be a set"
if size < set.size
any? { |o| set.include?(o) }
else
set.any? { |o| include?(o) }
end
end
# Returns true if the set and the given set have no element in
# common. This method is the opposite of +intersect?+.
#
# e.g.:
#
# require 'set'
# Set[1, 2, 3].disjoint? Set[3, 4] # => false
# Set[1, 2, 3].disjoint? Set[4, 5] # => true
def disjoint?(set)
!intersect?(set)
end
# Calls the given block once for each element in the set, passing
# the element as parameter. Returns an enumerator if no block is
# given.
def each(&block)
block or return enum_for(__method__) { size }
@hash.each_key(&block)
self
end
# Adds the given object to the set and returns self. Use +merge+ to
# add many elements at once.
def add(o)
@hash[o] = true
self
end
alias << add
# Adds the given object to the set and returns self. If the
# object is already in the set, returns nil.
def add?(o)
add(o) unless include?(o)
end
# Deletes the given object from the set and returns self. Use +subtract+ to
# delete many items at once.
def delete(o)
@hash.delete(o)
self
end
# Deletes the given object from the set and returns self. If the
# object is not in the set, returns nil.
def delete?(o)
delete(o) if include?(o)
end
# Deletes every element of the set for which block evaluates to
# true, and returns self. Returns an enumerator if no block is
# given.
def delete_if
block_given? or return enum_for(__method__) { size }
# @hash.delete_if should be faster, but using it breaks the order
# of enumeration in subclasses.
select { |o| yield o }.each { |o| @hash.delete(o) }
self
end
# Deletes every element of the set for which block evaluates to
# false, and returns self. Returns an enumerator if no block is
# given.
def keep_if
block_given? or return enum_for(__method__) { size }
# @hash.keep_if should be faster, but using it breaks the order of
# enumeration in subclasses.
reject { |o| yield o }.each { |o| @hash.delete(o) }
self
end
# Replaces the elements with ones returned by collect().
# Returns an enumerator if no block is given.
def collect!
block_given? or return enum_for(__method__) { size }
set = self.class.new
each { |o| set << yield(o) }
replace(set)
end
alias map! collect!
# Equivalent to Set#delete_if, but returns nil if no changes were
# made. Returns an enumerator if no block is given.
def reject!(&block)
block or return enum_for(__method__) { size }
n = size
delete_if(&block)
self if size != n
end
# Equivalent to Set#keep_if, but returns nil if no changes were
# made. Returns an enumerator if no block is given.
def select!(&block)
block or return enum_for(__method__) { size }
n = size
keep_if(&block)
self if size != n
end
# Merges the elements of the given enumerable object to the set and
# returns self.
def merge(enum)
if enum.instance_of?(self.class)
@hash.update(enum.instance_variable_get(:@hash))
else
do_with_enum(enum) { |o| add(o) }
end
self
end
# Deletes every element that appears in the given enumerable object
# and returns self.
def subtract(enum)
do_with_enum(enum) { |o| delete(o) }
self
end
# Returns a new set built by merging the set and the elements of the
# given enumerable object.
def |(enum)
dup.merge(enum)
end
alias + | ##
alias union | ##
# Returns a new set built by duplicating the set, removing every
# element that appears in the given enumerable object.
def -(enum)
dup.subtract(enum)
end
alias difference - ##
# Returns a new set containing elements common to the set and the
# given enumerable object.
def &(enum)
n = self.class.new
do_with_enum(enum) { |o| n.add(o) if include?(o) }
n
end
alias intersection & ##
# Returns a new set containing elements exclusive between the set
# and the given enumerable object. (set ^ enum) is equivalent to
# ((set | enum) - (set & enum)).
def ^(enum)
n = Set.new(enum)
each { |o| n.add(o) unless n.delete?(o) }
n
end
# Returns true if two sets are equal. The equality of each couple
# of elements is defined according to Object#eql?.
def ==(other)
if self.equal?(other)
true
elsif other.instance_of?(self.class)
@hash == other.instance_variable_get(:@hash)
elsif other.is_a?(Set) && self.size == other.size
other.all? { |o| @hash.include?(o) }
else
false
end
end
def hash # :nodoc:
@hash.hash
end
def eql?(o) # :nodoc:
return false unless o.is_a?(Set)
@hash.eql?(o.instance_variable_get(:@hash))
end
# Returns true if obj is a member of the set, and false otherwise.
#
# Used in case statements:
#
# case :apple
# when Set[:potato, :carrot] then 'vegetable'
# when Set[:apple, :banana] then 'fruit'
# end
# #=> "fruit"
#
# Or by itself:
#
# Set[1, 2, 3] === 2 #=> true
# Set[1, 2, 3] === 4 #=> false
#
alias === include?
# Classifies the set by the return value of the given block and
# returns a hash of {value => set of elements} pairs. The block is
# called once for each element of the set, passing the element as
# parameter.
#
# e.g.:
#
# require 'set'
# files = Set.new(Dir.glob("*.rb"))
# hash = files.classify { |f| File.mtime(f).year }
# p hash # => {2000=>#<Set: {"a.rb", "b.rb"}>,
# # 2001=>#<Set: {"c.rb", "d.rb", "e.rb"}>,
# # 2002=>#<Set: {"f.rb"}>}
#
# Returns an enumerator if no block is given.
def classify # :yields: o
block_given? or return enum_for(__method__) { size }
h = {}
each { |i|
(h[yield(i)] ||= self.class.new).add(i)
}
h
end
# Divides the set into a set of subsets according to the commonality
# defined by the given block.
#
# If the arity of the block is 2, elements o1 and o2 are in common
# if block.call(o1, o2) is true. Otherwise, elements o1 and o2 are
# in common if block.call(o1) == block.call(o2).
#
# e.g.:
#
# require 'set'
# numbers = Set[1, 3, 4, 6, 9, 10, 11]
# set = numbers.divide { |i,j| (i - j).abs == 1 }
# p set # => #<Set: {#<Set: {1}>,
# # #<Set: {11, 9, 10}>,
# # #<Set: {3, 4}>,
# # #<Set: {6}>}>
#
# Returns an enumerator if no block is given.
def divide(&func)
func or return enum_for(__method__) { size }
if func.arity == 2
require 'tsort'
class << dig = {} # :nodoc:
include TSort
alias tsort_each_node each_key
def tsort_each_child(node, &block)
fetch(node).each(&block)
end
end
each { |u|
dig[u] = a = []
each{ |v| func.call(u, v) and a << v }
}
set = Set.new()
dig.each_strongly_connected_component { |css|
set.add(self.class.new(css))
}
set
else
Set.new(classify(&func).values)
end
end
InspectKey = :__inspect_key__ # :nodoc:
# Returns a string containing a human-readable representation of the
# set. ("#<Set: {element1, element2, ...}>")
def inspect
ids = (Thread.current[InspectKey] ||= [])
if ids.include?(object_id)
return sprintf('#<%s: {...}>', self.class.name)
end
ids << object_id
begin
return sprintf('#<%s: {%s}>', self.class, to_a.inspect[1..-2])
ensure
ids.pop
end
end
alias to_s inspect
def pretty_print(pp) # :nodoc:
pp.text sprintf('#<%s: {', self.class.name)
pp.nest(1) {
pp.seplist(self) { |o|
pp.pp o
}
}
pp.text "}>"
end
def pretty_print_cycle(pp) # :nodoc:
pp.text sprintf('#<%s: {%s}>', self.class.name, empty? ? '' : '...')
end
end
#
# SortedSet implements a Set that guarantees that its elements are
# yielded in sorted order (according to the return values of their
# #<=> methods) when iterating over them.
#
# All elements that are added to a SortedSet must respond to the <=>
# method for comparison.
#
# Also, all elements must be <em>mutually comparable</em>: <tt>el1 <=>
# el2</tt> must not return <tt>nil</tt> for any elements <tt>el1</tt>
# and <tt>el2</tt>, else an ArgumentError will be raised when
# iterating over the SortedSet.
#
# == Example
#
# require "set"
#
# set = SortedSet.new([2, 1, 5, 6, 4, 5, 3, 3, 3])
# ary = []
#
# set.each do |obj|
# ary << obj
# end
#
# p ary # => [1, 2, 3, 4, 5, 6]
#
# set2 = SortedSet.new([1, 2, "3"])
# set2.each { |obj| } # => raises ArgumentError: comparison of Fixnum with String failed
#
class SortedSet < Set
@@setup = false
@@mutex = Mutex.new
class << self
def [](*ary) # :nodoc:
new(ary)
end
def setup # :nodoc:
@@setup and return
@@mutex.synchronize do
# a hack to shut up warning
alias_method :old_init, :initialize
begin
require 'rbtree'
module_eval <<-END, __FILE__, __LINE__+1
def initialize(*args)
@hash = RBTree.new
super
end
def add(o)
o.respond_to?(:<=>) or raise ArgumentError, "value must respond to <=>"
super
end
alias << add
END
rescue LoadError
module_eval <<-END, __FILE__, __LINE__+1
def initialize(*args)
@keys = nil
super
end
def clear
@keys = nil
super
end
def replace(enum)
@keys = nil
super
end
def add(o)
o.respond_to?(:<=>) or raise ArgumentError, "value must respond to <=>"
@keys = nil
super
end
alias << add
def delete(o)
@keys = nil
@hash.delete(o)
self
end
def delete_if
block_given? or return enum_for(__method__) { size }
n = @hash.size
super
@keys = nil if @hash.size != n
self
end
def keep_if
block_given? or return enum_for(__method__) { size }
n = @hash.size
super
@keys = nil if @hash.size != n
self
end
def merge(enum)
@keys = nil
super
end
def each(&block)
block or return enum_for(__method__) { size }
to_a.each(&block)
self
end
def to_a
(@keys = @hash.keys).sort! unless @keys
@keys
end
def freeze
to_a
super
end
END
end
# a hack to shut up warning
remove_method :old_init
@@setup = true
end
end
end
def initialize(*args, &block) # :nodoc:
SortedSet.setup
initialize(*args, &block)
end
end
module Enumerable
# Makes a set from the enumerable object with given arguments.
# Needs to +require "set"+ to use this method.
def to_set(klass = Set, *args, &block)
klass.new(self, *args, &block)
end
end
# =begin
# == RestricedSet class
# RestricedSet implements a set with restrictions defined by a given
# block.
#
# === Super class
# Set
#
# === Class Methods
# --- RestricedSet::new(enum = nil) { |o| ... }
# --- RestricedSet::new(enum = nil) { |rset, o| ... }
# Creates a new restricted set containing the elements of the given
# enumerable object. Restrictions are defined by the given block.
#
# If the block's arity is 2, it is called with the RestrictedSet
# itself and an object to see if the object is allowed to be put in
# the set.
#
# Otherwise, the block is called with an object to see if the object
# is allowed to be put in the set.
#
# === Instance Methods
# --- restriction_proc
# Returns the restriction procedure of the set.
#
# =end
#
# class RestricedSet < Set
# def initialize(*args, &block)
# @proc = block or raise ArgumentError, "missing a block"
#
# if @proc.arity == 2
# instance_eval %{
# def add(o)
# @hash[o] = true if @proc.call(self, o)
# self
# end
# alias << add
#
# def add?(o)
# if include?(o) || !@proc.call(self, o)
# nil
# else
# @hash[o] = true
# self
# end
# end
#
# def replace(enum)
# enum.respond_to?(:each) or raise ArgumentError, "value must be enumerable"
# clear
# enum.each_entry { |o| add(o) }
#
# self
# end
#
# def merge(enum)
# enum.respond_to?(:each) or raise ArgumentError, "value must be enumerable"
# enum.each_entry { |o| add(o) }
#
# self
# end
# }
# else
# instance_eval %{
# def add(o)
# if @proc.call(o)
# @hash[o] = true
# end
# self
# end
# alias << add
#
# def add?(o)
# if include?(o) || !@proc.call(o)
# nil
# else
# @hash[o] = true
# self
# end
# end
# }
# end
#
# super(*args)
# end
#
# def restriction_proc
# @proc
# end
# end
# Tests have been moved to test/test_set.rb.
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