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ruby--ruby/lib/set.rb
Jeremy Evans 258843106f Fix SortedSet subclasses that override initialize
The first time SortedSet#initialize is called, it overwrites
itself, then recalls #initialize, which results in calling the
subclass's initialize, not the current initialize.

Just inline the default initialize behavior to avoid this issue.

No test for this as it can only be triggered the very first time
that SortedSet#initialize is called.

Fixes [Bug #15830]
2019-09-06 14:20:22 -07:00

912 lines
24 KiB
Ruby

#--
# 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[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.
#
# Set[1, 2] # => #<Set: {1, 2}>
# Set[1, 2, 1] # => #<Set: {1, 2}>
# Set[1, 'c', :s] # => #<Set: {1, "c", :s}>
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.
#
# Set.new([1, 2]) #=> #<Set: {1, 2}>
# Set.new([1, 2, 1]) #=> #<Set: {1, 2}>
# Set.new([1, 'c', :s]) #=> #<Set: {1, "c", :s}>
# Set.new(1..5) #=> #<Set: {1, 2, 3, 4, 5}>
# Set.new([1, 2, 3]) { |x| x * x } #=> #<Set: {1, 4, 9}>
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.
#
# set = Set[1, 'c', :s] #=> #<Set: {1, "c", :s}>
# set.clear #=> #<Set: {}>
# set #=> #<Set: {}>
def clear
@hash.clear
self
end
# Replaces the contents of the set with the contents of the given
# enumerable object and returns self.
#
# set = Set[1, 'c', :s] #=> #<Set: {1, "c", :s}>
# set.replace([1, 2]) #=> #<Set: {1, 2}>
# set #=> #<Set: {1, 2}>
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.
#
# Set[1, 2].to_a #=> [1, 2]
# Set[1, 'c', :s].to_a #=> [1, "c", :s]
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.
#
# 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?+.
#
# 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.
#
# Set[1, 2].add(3) #=> #<Set: {1, 2, 3}>
# Set[1, 2].add([3, 4]) #=> #<Set: {1, 2, [3, 4]}>
# Set[1, 2].add(2) #=> #<Set: {1, 2}>
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.
#
# Set[1, 2].add?(3) #=> #<Set: {1, 2, 3}>
# Set[1, 2].add?([3, 4]) #=> #<Set: {1, 2, [3, 4]}>
# Set[1, 2].add?(2) #=> 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
# Equivalent to Set#select!
alias filter! select!
# 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.
#
# Set[1, 2, 3] | Set[2, 4, 5] #=> #<Set: {1, 2, 3, 4, 5}>
# Set[1, 5, 'z'] | (1..6) #=> #<Set: {1, 5, "z", 2, 3, 4, 6}>
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.
#
# Set[1, 3, 5] - Set[1, 5] #=> #<Set: {3}>
# Set['a', 'b', 'z'] - ['a', 'c'] #=> #<Set: {"b", "z"}>
def -(enum)
dup.subtract(enum)
end
alias difference -
# Returns a new set containing elements common to the set and the
# given enumerable object.
#
# Set[1, 3, 5] & Set[3, 2, 1] #=> #<Set: {3, 1}>
# Set['a', 'b', 'z'] & ['a', 'b', 'c'] #=> #<Set: {"a", "b"}>
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)).
#
# Set[1, 2] ^ Set[2, 3] #=> #<Set: {3, 1}>
# Set[1, 'b', 'c'] ^ ['b', 'd'] #=> #<Set: {"d", 1, "c"}>
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?.
#
# Set[1, 2] == Set[2, 1] #=> true
# Set[1, 3, 5] == Set[1, 5] #=> false
# Set['a', 'b', 'c'] == Set['a', 'c', 'b'] #=> true
# Set['a', 'b', 'c'] == ['a', 'c', 'b'] #=> false
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
# Resets the internal state after modification to existing elements
# and returns self.
#
# Elements will be reindexed and deduplicated.
def reset
if @hash.respond_to?(:rehash)
@hash.rehash # This should perform frozenness check.
else
raise FrozenError, "can't modify frozen #{self.class.name}" if frozen?
end
self
end
# Returns true if the given object is a member of the set,
# and false otherwise.
#
# Used in case statements:
#
# require 'set'
#
# case :apple
# when Set[:potato, :carrot]
# "vegetable"
# when Set[:apple, :banana]
# "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.
#
# require 'set'
# files = Set.new(Dir.glob("*.rb"))
# hash = files.classify { |f| File.mtime(f).year }
# 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).
#
# require 'set'
# numbers = Set[1, 3, 4, 6, 9, 10, 11]
# set = numbers.divide { |i,j| (i - j).abs == 1 }
# 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
def rehash
@keys = nil
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
@keys = nil
super
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.