Peter Stuifzand
90074d28d6
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continuous-integration/drone/push Build is passing
Solution: Paste license on top of all files. This does not change the license. It was already licensed as GPLv3.
80 lines
1.6 KiB
Go
80 lines
1.6 KiB
Go
/*
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* Ekster is a microsub server
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* Copyright (c) 2021 The Ekster authors
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package util
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import "reflect"
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// Rotate rotates values of an array, between index f and l with midpoint k
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func Rotate(a interface{}, f, k, l int) int {
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swapper := reflect.Swapper(a)
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if f == k {
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return l
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}
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if k == l {
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return f
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}
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next := k
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for {
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swapper(f, next)
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f++
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next++
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if f == k {
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k = next
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}
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if next == l {
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break
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}
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}
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ret := f
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for next = k; next != l; {
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swapper(f, next)
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f++
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next++
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if f == k {
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k = next
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} else if next == l {
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next = k
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}
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}
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return ret
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}
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// StablePartition partitions elements of the array between indices f and l according to predicate p
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func StablePartition(a interface{}, f, l int, p func(i int) bool) int {
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n := l - f
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if n == 0 {
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return f
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}
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if n == 1 {
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t := f
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if p(f) {
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t++
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}
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return t
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}
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m := f + (n / 2)
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return Rotate(a, StablePartition(a, f, m, p), m, StablePartition(a, m, l, p))
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}
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