# A rope is a kind of string but instead of being flat, it relies on a binary tree structure to store data.
module ropes
-import file
intrude import string
-# Structure, tuple containing a LeafNode and an Int
-# Used for methods like [] or has/has_only
-private class TupleLeafNodePos
- private var curr_node: LeafNode
- private var corrected_pos: Int
- private var visit_stack: List[TupleVisitNode]
-end
-
-# Abstract class, represents all the services offered by both mutable and immutable ropes
-abstract class Rope
- super Comparable
- super StringCapable
-
- # Cached version of self as a flat String
- private var str_representation: nullable String = null
-
- redef type OTHER: Rope
-
- # The first node of the hierarchy
- private var parent_node: RopeNode
-
- # Needed by the compiler to avoid producing an error with constructors in subclasses
- init do
- self.parent_node = new ConcatNode
- end
-
- # Initializes a new Rope with a text embedded in directly
- init with_string(str: String) do
- self.parent_node = new ConcatNode
- parent_node.as(ConcatNode).right_child = new LeafNode(str)
- parent_node.as(ConcatNode).update_data
- end
-
- # Returns a view on the rope
- fun chars: SequenceRead[Char]
- do
- return new CharRopeView(self)
- end
-
- # Gets the total length of the Rope
- fun length: Int
- do
- return parent_node.length
- end
-
- # Returns a flat version of self
- redef fun to_s
- do
- if self.str_representation == null then flatten
- return str_representation.as(not null)
- end
-
- # Stores a flat version of self in cache
- private fun flatten: FlatString
- do
- var native_final_str = calloc_string(length + 1)
-
- native_final_str[length] = '\0'
-
- var offset = 0
-
- var iter = new DFSRopeLeafIterator(self)
-
- while iter.is_ok do
- iter.item.value.as(FlatString).items.copy_to(native_final_str, iter.item.value.length, 0, offset)
- offset += iter.item.value.length
- iter.next
- end
-
- return native_final_str.to_s_with_length(length)
- end
-
- # Gets a node containing the substring to seek the char at the require position
- private fun get_node_for_pos(position: Int): TupleLeafNodePos
- do
- assert position >= 0 and position < self.length
-
- var curr_node: nullable RopeNode = parent_node
-
- var visit_stack = new List[TupleVisitNode]
-
- var curr_visit_tuple: TupleVisitNode
-
- loop
- if curr_node isa ConcatNode then
- curr_visit_tuple = new TupleVisitNode(curr_node)
- if curr_node.left_child != null and position < curr_node.left_child.length then
- curr_visit_tuple.left_visited = true
- curr_node = curr_node.left_child
- else if curr_node.right_child != null then
- curr_visit_tuple.left_visited = true
- curr_visit_tuple.right_visited = true
- if curr_node.left_child != null then position -= curr_node.left_child.length
- curr_node = curr_node.right_child
- else
- print "Fatal Error"
- abort
- end
- visit_stack.push(curr_visit_tuple)
- else if curr_node isa LeafNode then
- return new TupleLeafNodePos(curr_node, position, visit_stack)
- end
- end
- end
-
- # Concats two ropes and returns a new one
- fun +(other: Rope): Rope do
- var new_rope = new BufferRope
-
- var first_iter = new DFSRopeLeafIterator(self)
-
- while first_iter.is_ok do
- new_rope.append(first_iter.item.value)
- first_iter.next
- end
-
- var second_iter = new DFSRopeLeafIterator(other)
-
- while second_iter.is_ok do
- new_rope.append(second_iter.item.value)
- second_iter.next
- end
-
- return new_rope
- end
-
- # Returns a copy of several ropes concatenated
- #
- # Is equivalent to a chain of + operations
- # Except this one is optimized for performance
- fun multi_concat(ropes: Rope...): Rope
- do
- var new_rope = new BufferRope
-
- var self_iter = self.iterator
- while self_iter.is_ok do
- new_rope.append(self_iter.item.value)
- self_iter.next
- end
-
- for i in ropes do
- var iter = i.iterator
- while iter.is_ok do
- new_rope.append(iter.item.value)
- iter.next
- end
- end
-
- return new_rope
- end
-
- # Appends the content of self multiple times in a new Rope object
- fun *(repeats: Int): Rope do
-
- var new_rope = new BufferRope
-
- var str = self.to_s
-
- for i in [1 .. repeats] do new_rope.append(str)
-
- return new_rope
- end
-
- # Returns an iterator on self
- #
- # Unsafe modifications on a MutableRope
- #
- private fun iterator: Iterator[LeafNode] do return new DFSRopeLeafIterator(self)
-
- # Creates a subrope.
- #
- # var rope = (new BufferRope).append("abcd")
- #
- # assert rope.subrope(1, 2) == "bc"
- # assert rope.subrope(-1, ) == "a"
- # assert rope.subrope(1, 0) == ""
- # assert rope.subrope(2, 5) == "cd"
- #
- # A `index_from` index < 0 will be replaced by 0.
- # Unless a `count` value is > 0 at the same time.
- # In this case, `index_from += count` and `count -= index_from`.
- #
- fun subrope(index_from: Int, count: Int): Rope
- do
- assert count >= 0
-
- if index_from < 0 then
- count += index_from
- if count < 0 then count = 0
- index_from = 0
- end
-
- if count - index_from >= self.length then count = length - index_from
-
- var buffer = new BufferRope
-
- var iter = new DFSRopeLeafIterator.with_index(self, index_from)
-
- var curr_subrope_index = index_from - iter.pos
-
- while iter.is_ok do
- if count == 0 then break
- if curr_subrope_index > 0 then
- if count >= iter.item.value.length then
- buffer.append(iter.item.value.substring(curr_subrope_index, count))
- count -= iter.item.value.length - curr_subrope_index
- curr_subrope_index = 0
- else
- buffer.append(iter.item.value.substring(curr_subrope_index, count))
- break
- end
- else
- if count >= iter.item.value.length then
- buffer.append(iter.item.value)
- count -= iter.item.value.length
- else
- buffer.append(iter.item.value.substring(0, count))
- break
- end
- end
-
- iter.next
- end
-
- return buffer
- end
-
- # Returns an upper (capitalized) version of self
- fun to_upper: Rope
- do
- var new_rope = new BufferRope
- var iter = new DFSRopeLeafIterator(self)
- while iter.is_ok do
- new_rope.append(iter.item.value.to_upper)
- iter.next
- end
- return new_rope
- end
-
- # Returns a lower (minuscule) version of self
- fun to_lower: Rope
- do
- var new_rope = new BufferRope
- var iter = new DFSRopeLeafIterator(self)
- while iter.is_ok do
- new_rope.append(iter.item.value.to_lower)
- iter.next
- end
- return new_rope
- end
-
- ############################################################################
- # Comparable Refined Methods #
- ############################################################################
-
- # Compares the current Rope to another object (either another rope or a String)
- redef fun == (other)
- do
- if other == null or not (other isa Rope or other isa FlatText) then return false
- var self_iter = new RopeCharIterator(self)
- if other isa Rope then
- if self.length != other.length then return false
- var other_iterator = new RopeCharIterator(other)
- while self_iter.is_ok do
- if self_iter.item != other_iterator.item then return false
- self_iter.next
- other_iterator.next
- end
- else if other isa FlatText then
- var pos = 0
- if self.length != other.length then return false
- while self_iter.is_ok do
- if self_iter.item != other[pos] then return false
- pos += 1
- self_iter.next
- end
- end
- return true
- end
-
- # Checks if self is lesser than other
- #
- # Comparison done in lexicographical order
- # i.e. 'aa' < 'b'
- #
- redef fun <(other)
- do
- var other_iter = other.chars.iterator
- for i in self.chars do
- if not other_iter.is_ok then return false
- if i < other_iter.item then return true
- if i > other_iter.item then return false
- other_iter.next
- end
- if other_iter.is_ok then return true
- return false
- end
-
-end
-
-# Rope that can be modified
-#
-# /!\ Non Thread-safe /!\
-#
-class BufferRope
- super Rope
-
- var is_dirty: Bool = false
-
- init
- do
- super
- end
-
- redef init with_string(str)
- do
- super
- end
-
- ############################################################################
- # Tree Balancing Methods #
- ############################################################################
-
- # Performs a right rotation on a node of the Rope
- #
- # Root Pivot
- # / \ / \
- # Pivot Leaf3 => Leaf1 Root
- # / \ / \
- # Leaf1 Leaf2 Leaf2 Leaf3
- private fun rotate_right(root: ConcatNode)
- do
- assert root.left_child != null
- var pivot = root.left_child.as(ConcatNode)
- var root_new_left = pivot.right_child
- var root_parent = root.parent
-
- root.left_child = root_new_left
- pivot.right_child = root
- if root_parent == null then
- self.parent_node = pivot
- pivot.parent = null
- return
- end
-
- if root_parent.left_child == root then
- root_parent.left_child = pivot
- else
- root_parent.right_child = pivot
- end
-
- root.update_data
- pivot.update_data
- root_parent.update_data
- end
-
- # Performs a left rotation on a node of the Rope
- #
- # Root Pivot
- # / \ / \
- # Leaf1 Pivot => Root Leaf3
- # / \ / \
- # Leaf2 Leaf3 Leaf1 Leaf2
- private fun rotate_left(root: ConcatNode)
- do
- assert root.right_child != null
- var pivot = root.right_child.as(ConcatNode)
- var root_new_right = pivot.left_child
- var root_parent = root.parent
-
- root.right_child = root_new_right
- pivot.left_child = root
- if root_parent == null then
- self.parent_node = pivot
- pivot.parent = null
- return
- end
-
- if root_parent.left_child == root then
- root_parent.left_child = pivot
- else
- root_parent.right_child = pivot
- end
-
- root.update_data
- pivot.update_data
- root_parent.update_data
- end
-
- # Shortcut method to balance a node and its parents
- # based on the rules of the AVL Tree
- private fun balance_from_node(parent_node: nullable ConcatNode)
- do
- while parent_node != null do
- parent_node.update_data
- var node_balance = parent_node.balance_factor
- if node_balance < -1 or node_balance > 1 then
- balance_node(parent_node)
- end
- parent_node = parent_node.parent
- end
- end
-
- # Performs rotations to balance a node according to AVL Tree rules
- private fun balance_node(node: ConcatNode)
- do
- var balance_factor = node.balance_factor
- if balance_factor < -1 then
- var right_balance = node.right_child.balance_factor
- if right_balance < 0 then
- rotate_left(node)
- else
- rotate_right(node.right_child.as(ConcatNode))
- rotate_left(node)
- end
- else
- var left_balance = node.left_child.balance_factor
- if left_balance > 0 then
- rotate_right(node)
- else
- rotate_left(node.left_child.as(ConcatNode))
- rotate_right(node)
- end
- end
- end
-
- ############################################################################
- # BufferRope exclusive Methods #
- ############################################################################
-
- # Appends a new Collection[Char] at the end of the current rope
- fun append(str: String): BufferRope
- do
- var last_node = parent_node
-
- while last_node isa ConcatNode and last_node.right_child != null do
- last_node = last_node.right_child.as(not null)
- end
-
- if last_node isa ConcatNode then
- last_node.right_child = new LeafNode(str.to_s)
- else if last_node isa LeafNode then
- var last_node_parent = last_node.parent
- var new_concat = new ConcatNode
- last_node_parent.right_child = new_concat
- new_concat.left_child = last_node
- new_concat.right_child = new LeafNode(str.to_s)
- last_node = new_concat
- else
- print "Fatal Error, please report to the developers for more insight."
- abort
- end
-
- balance_from_node(last_node)
-
- is_dirty = true
-
- return self
- end
-
- # Variatic function to append several collections of Chars
- fun append_multi(strs: String...): BufferRope
- do
- for i in strs do
- append(i)
- end
- return self
- end
-
- # Adds a new Collection[Char] at the beginning of the rope
- fun prepend(str: String): BufferRope
- do
- var curr_node = parent_node
-
- while curr_node isa ConcatNode and curr_node.left_child != null do
- curr_node = curr_node.left_child.as(not null)
- end
-
- if curr_node isa ConcatNode then
- curr_node.left_child = new LeafNode(str.to_s)
- else if curr_node isa LeafNode then
- var parent = curr_node.parent
- var new_concat = new ConcatNode
- var new_leaf = new LeafNode(str.to_s)
- new_concat.left_child = new_leaf
- new_concat.right_child = curr_node
- parent.left_child = new_concat
- curr_node = new_concat
- else
- print "Fatal Error"
- abort
- end
-
- balance_from_node(curr_node)
-
- is_dirty = true
-
- return self
- end
-
- # Variatic function to prepend several collections of Chars
- fun prepend_multi(strs: String...): BufferRope
- do
- for i in strs do
- prepend(i)
- end
- return self
- end
-
- # Adds the content of `str` after self, does not create a new rope object
- fun concat(str: Rope): Rope
- do
- var other_iter = new DFSRopeLeafIterator(str)
-
- var modif_list = new List[String]
-
- while other_iter.is_ok do
- modif_list.push(other_iter.item.value)
- other_iter.next
- end
-
- while modif_list.length > 0 do
- self.append(modif_list.shift)
- end
-
- if not is_dirty then is_dirty = true
-
- return self
- end
-
- # Returns the content of the current BufferRope object as an ImmutableRope
- fun freeze: ImmutableRope
- do
- var buffer_rope = new BufferRope
- var new_rope = new ImmutableRope
-
- var iter = new DFSRopeLeafIterator(self)
-
- while iter.is_ok do
- buffer_rope.append(iter.item.value)
- iter.next
- end
-
- new_rope.parent_node = buffer_rope.parent_node
-
- if not is_dirty then new_rope.str_representation = self.str_representation
-
- return new_rope
- end
-
- # Unsafe method to convert self as an ImmutableRope
- #
- # To be used internally only
- private fun to_immutable: ImmutableRope
- do
- var immutable_self = new ImmutableRope
- immutable_self.parent_node = self.parent_node
- return immutable_self
- end
-
- ############################################################################
- # Rope refined Methods #
- ############################################################################
-
- redef fun subrope(index_from: Int, count: Int): BufferRope
- do
- return super.as(BufferRope)
- end
-
- redef fun *(repeats: Int): BufferRope
- do
- return super.as(BufferRope)
- end
-
- redef fun +(other: Rope): BufferRope
- do
- return super.as(BufferRope)
- end
-
- redef fun multi_concat(ropes: Rope...): BufferRope
- do
- return super.as(BufferRope)
- end
-
- # Refines to add a cache method, calculates only once for every modification
- # the string representation for self
- redef fun to_s
- do
- if self.str_representation == null or is_dirty then
- self.str_representation = flatten
- is_dirty = false
- end
- return self.str_representation.as(not null)
- end
-
-end
-
-# Rope that cannot be modified
-class ImmutableRope
- super Rope
-
- init
- do
- super
- end
-
- redef init with_string(str)
- do
- super
- end
-
- ############################################################################
- # Rope refined Methods #
- ############################################################################
-
- redef fun subrope(index_from: Int, count: Int): ImmutableRope
- do
- return (super.as(BufferRope)).to_immutable
- end
-
- redef fun *(repeats: Int): ImmutableRope
- do
- return (super.as(BufferRope)).to_immutable
- end
-
- redef fun +(other: Rope): ImmutableRope
- do
- return (super.as(BufferRope)).to_immutable
- end
-
- redef fun multi_concat(ropes: Rope...): ImmutableRope
- do
- return (super.as(BufferRope)).to_immutable
- end
-
-end
-
-############################################
-# Rope view classes #
-############################################
-
-class CharRopeView
- super SequenceRead[Char]
-
- # Targeted Rope for the view
- private var target: Rope
-
- init(tgt: Rope)
- do
- self.target = tgt
- end
-
- redef fun [](position)
- do
- var tuple = target.get_node_for_pos(position)
- return tuple.curr_node.value[tuple.corrected_pos]
- end
-
- redef fun first do return self[0]
-
- redef fun index_of(char)
- do
- var intern_iter = new RopeCharIterator(target)
- while intern_iter.is_ok do
- if intern_iter.item == char then return intern_iter.index
- intern_iter.next
- end
- return -1
- end
-
- redef fun iterator do
- return new RopeCharIterator(target)
- end
-
- redef fun last do return self[self.length-1]
-
- redef fun length do return target.length
-
- redef fun count(item)
- do
- var count = 0
- var iter = self.iterator
-
- for i in self do
- if i == item then count += 1
- end
-
- return count
- end
-
- redef fun has_only(item)
- do
- for i in self do
- if i != item then return false
- end
- return true
- end
-
- redef fun is_empty do return length == 0
-
- redef fun to_a do
- return to_s.to_a
- end
-
- redef fun to_s do
- return target.to_s
- end
-
- redef fun ==(other)
- do
- if not other isa SequenceRead[Char] then return false
-
- if self.length != other then return false
-
- var iter = other.iterator
-
- for i in self do
- if i != iter.item then return false
- iter.next
- end
-
- return true
- end
-
-end
-
-###########################################
-# Iterator classes #
-###########################################
-
-# A tuple representing the state of a node for a tree parsing algorithm
-private class TupleVisitNode
-
- init(tgt: ConcatNode)
- do
- self.node = tgt
- end
-
- private var node: ConcatNode
-
- private var left_visited = false
- private var right_visited = false
-
-end
-
-# Any kind of iterator parsing a Rope for LeafNodes
-private abstract class RopeIterator
- super IndexedIterator[LeafNode]
-
- # Rope meant to be visited
- private var _target: Rope
-
- private fun target: Rope do return self._target
-
- # Position in target
- private var pos = 0
-
- init(tgt: Rope)
- do
- self._target = tgt
- end
-
- init with_index(tgt: Rope, index: Int)
- do
- self._target = tgt
- end
-
-end
-
-# Iterator returning the content of a rope one char at a time
-class RopeCharIterator
- super IndexedIterator[Char]
-
- # The iterator used to visit the rope
- private var sub_str_iter: DFSRopeLeafIterator
-
- # The current position in the rope
- private var abs_pos = 0
-
- # The position in the current substring
- private var sub_pos: Int = 0
-
- # The substring contained in the current node visited by `sub_str_iter`
- private var curr_substring: nullable String
-
- init(tgt: Rope)
- do
- sub_str_iter = new DFSRopeLeafIterator(tgt)
- if sub_str_iter.is_ok then curr_substring = sub_str_iter.item.value
- end
-
- redef fun item do return curr_substring[sub_pos]
-
- redef fun is_ok
- do
- if sub_str_iter.is_ok then return true
- if not sub_str_iter.is_ok and curr_substring != null and sub_pos < curr_substring.length then return true
- return false
- end
-
- redef fun next
- do
- assert is_ok
- if sub_pos < curr_substring.length - 1 then
- sub_pos += 1
- else
- sub_str_iter.next
- if sub_str_iter.is_ok then
- curr_substring = sub_str_iter.item.value
- sub_pos = 0
- else
- sub_pos = curr_substring.length
- end
- end
- abs_pos += 1
- end
-
- redef fun index do return abs_pos
-
-end
-
-# Special kind of iterator
-#
-# Performs a Depth-First Search on RopeLeaf items
-#
-private class DFSRopeLeafIterator
- super RopeIterator
-
- # Stack of the visited nodes in the rope
- private var visit_stack = new List[TupleVisitNode]
-
- # The leaf node being visited by the iterator
- private var curr_leaf: nullable LeafNode
-
- init(tgt: Rope)
- do
- super
-
- var first_node = target.parent_node
-
- if first_node isa ConcatNode then
- visit_stack.push(new TupleVisitNode(first_node))
- else if first_node isa LeafNode then
- curr_leaf = first_node
- return
- end
-
- next_body
- end
-
- # Creates a new iterator on `tgt` starting at `index`
- redef init with_index(tgt: Rope, index: Int)
- do
- super
-
- var returned_tuple = target.get_node_for_pos(index)
- curr_leaf = returned_tuple.curr_node
- visit_stack = returned_tuple.visit_stack
- pos = index - returned_tuple.corrected_pos
- end
-
- redef fun is_ok do return curr_leaf != null
-
- redef fun next
- do
- assert is_ok
- pos += curr_leaf.value.length
- next_body
- end
-
- private fun next_body
- do
- var next_node: nullable RopeNode
- while not visit_stack.is_empty do
- var curr_concat_tuple = visit_stack.last
- if not curr_concat_tuple.left_visited then
-
- curr_concat_tuple.left_visited = true
-
- next_node = curr_concat_tuple.node.left_child
-
- if next_node == null then continue
-
- if next_node isa ConcatNode then
- visit_stack.push(new TupleVisitNode(next_node))
- else if next_node isa LeafNode then
- curr_leaf = next_node
- return
- end
-
- else if not curr_concat_tuple.right_visited then
-
- curr_concat_tuple.right_visited = true
-
- next_node = curr_concat_tuple.node.right_child
-
- if next_node == null then continue
-
- if next_node isa ConcatNode then
- visit_stack.push(new TupleVisitNode(next_node))
- else if next_node isa LeafNode then
- curr_leaf = next_node
- return
- end
-
- else
- visit_stack.pop
- end
- end
- self.curr_leaf = null
- end
-
- redef fun item
- do
- assert is_ok
- return curr_leaf.as(not null)
- end
-
-end
-
-###########################################
-# Node classes #
-###########################################
-
-# A node for a Rope
-private abstract class RopeNode
-
- private var _length = 0
-
- private var parent: nullable ConcatNode = null
-
- private var height = 0
-
- # The balance factor of a node, if it is a Leaf, it equals its length
- # Else, it will be equal to the difference between the height on the left and on the right
- private fun balance_factor: Int do return height end
-
- fun length: Int do return _length
-
- private fun length=(len: Int)
- do
- _length = len
- end
-end
-
-# Node that represents a concatenation between two nodes (of any RopeNode type)
-private class ConcatNode
- super RopeNode
-
- private var _left_child: nullable RopeNode = null
- private var _right_child: nullable RopeNode = null
-
- private fun left_child: nullable RopeNode
- do
- if _left_child != null then
- return _left_child
- else
- return null
- end
- end
-
- private fun right_child: nullable RopeNode
- do
- if _right_child != null then
- return _right_child
- else
- return null
- end
- end
-
- private fun left_child=(new_node: nullable RopeNode)
- do
- self._left_child = new_node
- new_node.parent = self
- update_data
- end
-
- private fun right_child=(new_node: nullable RopeNode)
- do
- self._right_child = new_node
- new_node.parent = self
- update_data
- end
-
- # Updates the internal data of the current node
- #
- # Concretely, updates the length and the height of the node
- private fun update_data
- do
- self.length = 0
- self.height = 1
- if left_child != null then
- self.length += left_child.length
- if left_child.height + 1 > self.height then self.height = left_child.height + 1
- end
- if right_child != null then
- self.length += right_child.length
- if right_child.height + 1 > self.height then self.height = right_child.height + 1
- end
- end
-
- # Computes and returns the balance factor (used for AVL trees)
- #
- # Formula : left.height - right.height
- redef private fun balance_factor
- do
- var left_height = 0
- var right_height = 0
- if left_child != null then left_height = left_child.height
- if right_child != null then right_height = right_child.height
- return left_height - right_height
- end
-end
-
-# A leaf node contains a substring of some sort
-private class LeafNode
- super RopeNode
-
- # Encapsulated string in the leaf node
- private var _value: String
-
- init(val: String)
- do
- self._value = val.to_s
- self.length = val.length
- end
-
- private fun value: String do return self._value
-
- private fun value= (val: String)
- do
- _value = val
- end
-end
-
-#####################################################
-# Foreign classes refinement #
-#####################################################
-
-redef class String
- redef fun ==(other)
- do
- if other isa Rope then
- return other == self
- else
- return super
- end
- end
-end
-
-redef class Buffer
- redef fun ==(other)
- do
- if other isa Rope then
- return other == self
- else
- return super
- end
- end
-end
nitlanguage / nit.git / commitdiff