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ecd8125771
Co-authored-by: silicons <2003111+silicons@users.noreply.github.com> Co-authored-by: silicons <no@you.cat>
90 lines
2.2 KiB
Plaintext
90 lines
2.2 KiB
Plaintext
//* This file is explicitly licensed under the MIT license. *//
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//* Copyright (c) 2023 Citadel Station developers. *//
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/**
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* An array-backed priority queue.
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*
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* The "front" of the queue is popped first; check comparators.dm for what this means.
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*/
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/datum/priority_queue
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/// comparaison function
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var/procpath/comparison
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/// internal array
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var/list/array = list()
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/datum/priority_queue/New(cmp)
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src.comparison = cmp
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array = list()
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/datum/priority_queue/proc/is_empty()
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return length(array) == 0
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/datum/priority_queue/proc/enqueue(entry)
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array += entry
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bubble_up(length(array))
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/datum/priority_queue/proc/dequeue()
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if(length(array) == 0)
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return null
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. = array[1]
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array.Swap(1, length(array))
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--array.len
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bubble_down(1)
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/datum/priority_queue/proc/peek()
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return length(array)? array[1] : null
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// todo: define this
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/datum/priority_queue/proc/bubble_up(index)
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while(index >= 2 && call(comparison)(array[index], array[index / 2]) < 0)
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array.Swap(index, index / 2)
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index /= 2
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// todo: define this
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/datum/priority_queue/proc/bubble_down(index)
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var/length = length(array)
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var/next = index * 2
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while(next <= length)
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// left always exists, right doesn't necessarily exist
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if(call(comparison)(array[next], array[index]) < 0)
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if(next < length && call(comparison)(array[next], array[next + 1]) > 0)
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array.Swap(index, next + 1)
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index = next + 1
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else
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array.Swap(index, next)
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index = next
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else if(next < length && call(comparison)(array[next + 1], array[index]) < 0)
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array.Swap(index, next + 1)
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index = next + 1
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else
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break
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next = index * 2
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/**
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* returns copy of list of entries in no particular order
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*/
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/datum/priority_queue/proc/flattened()
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return array.Copy()
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/datum/priority_queue/proc/remove_index(index)
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var/length = length(array)
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if(!index || index > length)
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return
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if(index == length)
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. = array[index]
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--array.len
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return
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. = array[index]
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array.Swap(index, length)
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--array.len
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bubble_down(index)
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/datum/priority_queue/proc/find(entry)
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return array.Find(entry)
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/datum/priority_queue/proc/remove_entry(entry)
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return remove_index(array.Find(entry))
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/datum/priority_queue/proc/size()
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return length(array)
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