132 lines
4.2 KiB
Nim
132 lines
4.2 KiB
Nim
# Nimbus
|
|
# Copyright (c) 2018 Status Research & Development GmbH
|
|
# Licensed under either of
|
|
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
|
|
# http://www.apache.org/licenses/LICENSE-2.0)
|
|
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
|
|
# http://opensource.org/licenses/MIT)
|
|
# at your option. This file may not be copied, modified, or distributed except
|
|
# according to those terms.
|
|
|
|
import
|
|
./rbtree_desc,
|
|
./rbtree_rotate,
|
|
../results
|
|
|
|
{.push raises: [Defect].}
|
|
|
|
# ----------------------------------------------------------------------- ------
|
|
# Private functions
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc insertRoot[C,K](rbt: RbTreeRef[C,K]; key: K): C {.inline.} =
|
|
## Insert item `x` into an empty tree.
|
|
rbt.root = RbNodeRef[C](
|
|
casket: rbt.mkc(key))
|
|
rbt.size = 1
|
|
rbt.root.casket
|
|
|
|
proc insertNode[C,K](rbt: RbTreeRef[C,K]; key: K): RbResult[C] {.inline.} =
|
|
## Insert item `key` into a non-empty tree.
|
|
|
|
doAssert not rbt.root.isNil
|
|
|
|
var
|
|
dir = rbLeft
|
|
last = dir # always previous value of `dir`
|
|
insertOk = false
|
|
head = RbNodeRef[C](
|
|
link: [nil, rbt.root]) # black fake tree root
|
|
|
|
# ancestry line: t -> g -> p -> q
|
|
greatGrandParent = head # ancestor, fake (black) super root
|
|
grandParent: RbNodeRef[C] # grandparent => NIL
|
|
parent: RbNodeRef[C] # parent => NIL
|
|
q = rbt.root # initialise iterator to not-NIL tree root
|
|
|
|
# Search down the tree for a place to insert
|
|
while true:
|
|
|
|
if q.isNil:
|
|
# Insert new (red) node at the first NIL link
|
|
insertOk = true
|
|
q = RbNodeRef[C](
|
|
casket: rbt.mkc(key))
|
|
q.isRed = true
|
|
parent.link[dir] = q
|
|
|
|
elif q.linkLeft.isRed and q.linkRight.isRed:
|
|
# Simple red violation: colour flip
|
|
q.isRed = true
|
|
q.linkLeft.isRed = false # aka black
|
|
q.linkRight.isRed = false # aka black
|
|
|
|
# Fix red violation: rotations necessary
|
|
if q.isRed and parent.isRed:
|
|
let dir2 = (greatGrandParent.linkRight == grandParent).toDir
|
|
greatGrandParent.link[dir2] =
|
|
if parent.link[last] == q: grandParent.rbTreeRotateSingle(not last)
|
|
else: grandParent.rbTreeRotateDouble(not last)
|
|
|
|
# Mark traversal path unusable
|
|
rbt.dirty = rbt.dirty or rbTreeReBalancedFlag
|
|
|
|
# Stop working if we inserted a node. This check also disallows
|
|
# duplicates in the tree.
|
|
let diff = rbt.cmp(q.casket,key)
|
|
if diff == 0:
|
|
break ;
|
|
|
|
last = dir
|
|
dir = (diff < 0).toDir
|
|
|
|
# Shift the helpers down the ancestry line
|
|
if not grandParent.isNil:
|
|
greatGrandParent = grandParent
|
|
grandParent = parent
|
|
parent = q
|
|
q = q.link[dir]
|
|
|
|
# End while
|
|
|
|
# Update the root (it may be different)
|
|
rbt.root = head.linkRight
|
|
|
|
# Make the root black for simplified logic
|
|
rbt.root.isRed = false # aka black
|
|
|
|
# Save last node in cache (speeds up some find operation)
|
|
rbt.cache = q
|
|
|
|
if insertOk:
|
|
rbt.size.inc
|
|
return ok(q.casket)
|
|
|
|
return err(rbExists)
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Public
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc rbTreeInsert*[C,K](rbt: RbTreeRef[C,K]; key: K): RbResult[C] =
|
|
## Generic red-black tree function, inserts a data container `casket` derived
|
|
## from argument `key` into the red-black tree.
|
|
##
|
|
## If a new node was successfully created, the function returns the `casket`
|
|
## data container matching the `key` argument (i.e.
|
|
## `rbt.cmp(casket,key) == 0`). Otherwise, if the `key` argument was in the
|
|
## tree already an error code is returned. In that case, the data container
|
|
## can can be retrieved with `rbTreeFindEq()`.
|
|
##
|
|
## :Ackn:
|
|
## `jsw_rbinsert()` from jsw_rbtree.c from captured C library
|
|
## `jsw_rbtree.zip <https://web.archive.org/web/20160428112900/http://eternallyconfuzzled.com/libs/jsw_rbtree.zip>`_.
|
|
##
|
|
if rbt.root.isNil:
|
|
return ok(rbt.insertRoot(key))
|
|
rbt.insertNode(key)
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# End
|
|
# ------------------------------------------------------------------------------
|