99 lines
3.0 KiB
Nim
99 lines
3.0 KiB
Nim
# Nimbus
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# Copyright (c) 2018-2022 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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# http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
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# http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed except
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# according to those terms.
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import
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./rbtree_desc
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type
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RbTreeFlushDel*[C] = proc(c: var C) {.gcsafe.}
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when (NimMajor, NimMinor) < (1, 4):
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{.push raises: [Defect].}
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else:
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{.push raises: [].}
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# ----------------------------------------------------------------------- ------
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# Private
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# ------------------------------------------------------------------------------
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# Default clean up function
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proc defaultClup[C](casket: var C) {.inline.} =
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# smarty here ...
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discard
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# ----------------------------------------------------------------------- ------
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# Public
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# ------------------------------------------------------------------------------
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proc rbTreeFlush*[C,K](rbt: RbTreeRef[C,K];
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clup: RbTreeFlushDel[C] = nil): bool
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{.gcsafe,discardable.} =
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## Clears/flushes a valid red-black tree while passing each data container
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## `casket` to the clean up argument function `clup()` before removing it.
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##
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## The flush function returns `false` and stops immediately if another flush
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## instance is already running. On a single thread execution model, this can
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## only happen if this very same function is called from within the cleanup
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## function argument `clup()`.
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##
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## :Ackn:
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## `jsw_rbdelete()` from jsw_rbtree.c from captured C library
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## `jsw_rbtree.zip <https://web.archive.org/web/20160428112900/http://eternallyconfuzzled.com/libs/jsw_rbtree.zip>`_.
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##
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if (rbt.dirty and rbTreeFlushDataFlag) != 0:
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return false
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rbt.dirty = rbt.dirty or rbTreeFlushDataFlag
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# clear node cache
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rbt.cache = nil
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var
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cleanUp = clup
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save: RbNodeRef[C]
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it = rbt.root
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if cleanUp.isNil:
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# Need `proc()` wrapper around generic `defaultClup[C]()` as the function
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# pointer `defaultClup` exists only with its incarnation,
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cleanUp = proc(c: var C) = c.defaultClup
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# GC hint, reset node reference early so there is no remaining
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# top level link left when cleaning up right node chain
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rbt.root = nil
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# Rotate away the left links so that we can treat this like
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# the destruction of a linked list
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while not it.isNil:
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if it.linkLeft.isNil:
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# No left links, just kill the node and move on
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save = it.linkRight
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it.casket.cleanUp
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it = nil # GC hint
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else:
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# Rotate away the left link and check again
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save = it.linkLeft
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it.linkLeft = save.linkRight
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save.linkRight = it
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it = save
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# End while
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rbt.size = 0
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rbt.dirty = rbTreeNodesDeletedFlag or rbTreeReBalancedFlag
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true
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# ----------------------------------------------------------------------- ------
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# End
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# ------------------------------------------------------------------------------
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