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98 lines
2.5 KiB
Nim
Executable File
98 lines
2.5 KiB
Nim
Executable File
#
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#
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# The Nimrod Compiler
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# (c) Copyright 2010 Andreas Rumpf
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#
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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#
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# This module implements a generic doubled linked list.
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type
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PListEntry* = ref TListEntry
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TListEntry* = object of TObject
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prev*, next*: PListEntry
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TStrEntry* = object of TListEntry
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data*: string
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PStrEntry* = ref TStrEntry
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TLinkedList* = object # for the "find" operation:
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head*, tail*: PListEntry
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Counter*: int
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TCompareProc* = proc (entry: PListEntry, closure: Pointer): bool
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proc InitLinkedList*(list: var TLinkedList) =
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list.Counter = 0
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list.head = nil
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list.tail = nil
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proc Append*(list: var TLinkedList, entry: PListEntry) =
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Inc(list.counter)
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entry.next = nil
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entry.prev = list.tail
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if list.tail != nil:
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assert(list.tail.next == nil)
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list.tail.next = entry
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list.tail = entry
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if list.head == nil: list.head = entry
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proc Contains*(list: TLinkedList, data: string): bool =
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var it = list.head
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while it != nil:
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if PStrEntry(it).data == data:
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return true
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it = it.next
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proc newStrEntry(data: string): PStrEntry =
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new(result)
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result.data = data
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proc AppendStr*(list: var TLinkedList, data: string) =
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append(list, newStrEntry(data))
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proc IncludeStr*(list: var TLinkedList, data: string): bool =
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if Contains(list, data): return true
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AppendStr(list, data) # else: add to list
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proc Prepend*(list: var TLinkedList, entry: PListEntry) =
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Inc(list.counter)
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entry.prev = nil
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entry.next = list.head
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if list.head != nil:
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assert(list.head.prev == nil)
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list.head.prev = entry
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list.head = entry
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if list.tail == nil: list.tail = entry
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proc PrependStr*(list: var TLinkedList, data: string) =
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prepend(list, newStrEntry(data))
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proc InsertBefore*(list: var TLinkedList, pos, entry: PListEntry) =
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assert(pos != nil)
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if pos == list.head:
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prepend(list, entry)
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else:
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Inc(list.counter)
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entry.next = pos
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entry.prev = pos.prev
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if pos.prev != nil: pos.prev.next = entry
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pos.prev = entry
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proc Remove*(list: var TLinkedList, entry: PListEntry) =
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Dec(list.counter)
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if entry == list.tail:
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list.tail = entry.prev
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if entry == list.head:
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list.head = entry.next
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if entry.next != nil: entry.next.prev = entry.prev
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if entry.prev != nil: entry.prev.next = entry.next
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proc Find*(list: TLinkedList, fn: TCompareProc, closure: Pointer): PListEntry =
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result = list.head
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while result != nil:
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if fn(result, closure): return
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result = result.next
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