Class: ArrayEnumerator
- Inherits:
-
Object
- Object
- ArrayEnumerator
- Includes:
- Enumerable
- Defined in:
- lib/array_enumerator.rb
Overview
This class is ment as an enumerator but with a cache that enables it to emulate array-functionality (first, empty and so on). If elements goes out of memory, then the array becomes corrupted and methods like ‘first’ and ‘slice’ will no longer work (raise errors).
Defined Under Namespace
Classes: ArrayCorruptedError, CannotCallBeforeEnd
Instance Method Summary collapse
- #<<(object) ⇒ Object
-
#[](key) ⇒ Object
This method should only be used with ‘each_index’.
- #any? ⇒ Boolean
- #collect ⇒ Object (also: #map)
- #compact ⇒ Object
-
#each(&block) ⇒ Object
Returns each element and releases them from cache.
-
#each_index(&block) ⇒ Object
Yields each count-key and caches element for returning it by using the []-method.
-
#empty? ⇒ Boolean
Returns true if the array-enumerator is empty.
-
#first ⇒ Object
Cache the first elements (if not cached already) and returns it.
-
#initialize(enum = nil, &blk) ⇒ ArrayEnumerator
constructor
Takes an enumerator to work with as argument.
-
#length ⇒ Object
Returns the counted length.
- #none? ⇒ Boolean
- #push(object) ⇒ Object
- #reject ⇒ Object (also: #delete_if)
- #select ⇒ Object (also: #keep_if)
-
#shift(*args) ⇒ Object
Caches necessary needed elements and then returns the result as on a normal array.
-
#slice(*args) ⇒ Object
Giving slice negaive arguments will force it to cache all elements and crush the memory for big results.
-
#to_a ⇒ Object
(also: #to_ary)
Returns a normal array with all elements.
-
#to_enum ⇒ Object
Returns a enumerator that can yield all the elements (both cached and future un-cached ones).
- #to_s ⇒ Object (also: #inspect)
- #unshift(object) ⇒ Object
Constructor Details
#initialize(enum = nil, &blk) ⇒ ArrayEnumerator
Takes an enumerator to work with as argument.
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# File 'lib/array_enumerator.rb', line 9 def initialize(enum = nil, &blk) if enum #The enumerator being used. @enum = enum elsif blk @enum = Enumerator.new do |yielder| blk.call(yielder) end else raise "No enum or block was given." end @eles = [] @end_eles = [] # Used to calculate length without depending corruption. @length_cache = 0 # If the virtual array has become corrupted because of forgotten elements (by calling each and enumerating through elements). @array_corrupted = false # To allow the object to be thread-safe. @mutex = Mutex.new end |
Instance Method Details
#<<(object) ⇒ Object
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# File 'lib/array_enumerator.rb', line 39 def <<(object) push(object) end |
#[](key) ⇒ Object
This method should only be used with ‘each_index’.
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# File 'lib/array_enumerator.rb', line 89 def [](key) if @each_index && @each_index.key?(key) ret = @each_index[key] @each_index.delete(key) return ret end raise "This only works when also using 'each_index'. Invalid key: '#{key}'." end |
#any? ⇒ Boolean
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# File 'lib/array_enumerator.rb', line 74 def any? !empty? end |
#collect ⇒ Object Also known as: map
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# File 'lib/array_enumerator.rb', line 224 def collect check_corrupted return ArrayEnumerator.new do |y| each do |element| y << yield(element) end end end |
#compact ⇒ Object
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# File 'lib/array_enumerator.rb', line 174 def compact reject { |element| element == nil } end |
#each(&block) ⇒ Object
Returns each element and releases them from cache.
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# File 'lib/array_enumerator.rb', line 79 def each(&block) if block to_enum.each(&block) return nil else return to_enum end end |
#each_index(&block) ⇒ Object
Yields each count-key and caches element for returning it by using the []-method.
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# File 'lib/array_enumerator.rb', line 100 def each_index(&block) enum = Enumerator.new do |yielder| begin @each_index = {} count = 0 self.each do |ele| # Remove previous element to not take up memory. count_before = count - 1 @each_index.delete(count_before) if @each_index.key?(count_before) # Add current element to cache. @each_index[count] = ele yield(count) # Increase count for next run. count += 1 end ensure @each_index = nil end end if block enum.each(&block) return nil else return enum end end |
#empty? ⇒ Boolean
Returns true if the array-enumerator is empty.
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# File 'lib/array_enumerator.rb', line 56 def empty? if @empty == nil cache_ele if @length_cache == 0 if @length_cache > 0 @empty = false else @empty = true end end return @empty end |
#first ⇒ Object
Cache the first elements (if not cached already) and returns it.
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# File 'lib/array_enumerator.rb', line 49 def first check_corrupted cache_ele if @eles.empty? return @eles.first end |
#length ⇒ Object
Returns the counted length. Can only be called after the end of the enumerator has been reached.
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# File 'lib/array_enumerator.rb', line 152 def length raise CannotCallBeforeEnd, "Cant call length before the end has been reached." unless @end return @length_cache end |
#none? ⇒ Boolean
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# File 'lib/array_enumerator.rb', line 70 def none? empty? end |
#push(object) ⇒ Object
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# File 'lib/array_enumerator.rb', line 34 def push(object) raise ArrayCorruptedError if @end @end_eles << object end |
#reject ⇒ Object Also known as: delete_if
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# File 'lib/array_enumerator.rb', line 168 def reject select { |element| !yield(element) } end |
#select ⇒ Object Also known as: keep_if
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# File 'lib/array_enumerator.rb', line 157 def select return ArrayEnumerator.new do |y| check_corrupted each do |element| y << element if yield(element) end end end |
#shift(*args) ⇒ Object
Caches necessary needed elements and then returns the result as on a normal array.
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# File 'lib/array_enumerator.rb', line 201 def shift(*args) check_corrupted if args[0] amount = args[0] else amount = 1 end @eles ||= [] cache_ele(amount - @eles.length) if @eles.length < amount res = @eles.shift(*args) # Since we are removing an element, the length should go down with the amount of elements captured. if args[0] @length_cache -= res.length else @length_cache -= 1 end return res end |
#slice(*args) ⇒ Object
Giving slice negaive arguments will force it to cache all elements and crush the memory for big results.
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# File 'lib/array_enumerator.rb', line 179 def slice(*args) check_corrupted if args[0].is_a?(Range) && !args[1] need_eles = args[0].begin + args[0].end elsif args[0] && !args[1] need_eles = args[0] elsif args[0] && args[1] && args[0] > 0 && args[1] > 0 need_eles = args[0] + args[1] elsif args[0] < 0 || args[1] < 0 raise ArgumentError, "Slice cant take negative arguments." else raise ArgumentError, "Dont now what to do with args: '#{args}'." end @eles ||= [] cache_eles = need_eles - @eles.length if need_eles cache_ele(cache_eles) if need_eles && cache_eles > 0 return @eles.slice(*args) end |
#to_a ⇒ Object Also known as: to_ary
Returns a normal array with all elements. Can also raise corrupted error if elements have been thrown out.
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# File 'lib/array_enumerator.rb', line 237 def to_a check_corrupted cache_all return @eles end |
#to_enum ⇒ Object
Returns a enumerator that can yield all the elements (both cached and future un-cached ones).
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# File 'lib/array_enumerator.rb', line 132 def to_enum check_corrupted @array_corrupted = true return Enumerator.new do |yielder| while ele = @eles.shift yielder << ele end yield_rest do |ele| yielder << ele end while ele = @end_eles.shift yielder << ele end end end |
#to_s ⇒ Object Also known as: inspect
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# File 'lib/array_enumerator.rb', line 245 def to_s "<ArrayEnumerator array_corrupted=\"#{@array_corrupted}\" length_cache=\"#{@length_cache}\">" end |
#unshift(object) ⇒ Object
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# File 'lib/array_enumerator.rb', line 43 def unshift(object) check_corrupted @eles << object end |