808 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			808 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser 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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// The go-ethereum library 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 Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package pot see doc.go
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package pot
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import (
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	"fmt"
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	"sync"
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)
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const (
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	maxkeylen = 256
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)
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// Pot is the node type (same for root, branching node and leaf)
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type Pot struct {
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	pin  Val
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	bins []*Pot
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	size int
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	po   int
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}
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// Val is the element type for Pots
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type Val interface{}
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// Pof is the proximity order comparison operator function
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type Pof func(Val, Val, int) (int, bool)
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// NewPot constructor. Requires a value of type Val to pin
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// and po to point to a span in the Val key
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// The pinned item counts towards the size
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func NewPot(v Val, po int) *Pot {
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	var size int
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	if v != nil {
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		size++
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	}
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	return &Pot{
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		pin:  v,
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		po:   po,
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		size: size,
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	}
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}
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// Pin returns the pinned element (key) of the Pot
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func (t *Pot) Pin() Val {
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	return t.pin
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}
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// Size returns the number of values in the Pot
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func (t *Pot) Size() int {
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	if t == nil {
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		return 0
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	}
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	return t.size
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}
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// Add inserts a new value into the Pot and
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// returns the proximity order of v and a boolean
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// indicating if the item was found
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// Add called on (t, v) returns a new Pot that contains all the elements of t
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// plus the value v, using the applicative add
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// the second return value is the proximity order of the inserted element
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// the third is boolean indicating if the item was found
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func Add(t *Pot, val Val, pof Pof) (*Pot, int, bool) {
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	return add(t, val, pof)
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}
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func (t *Pot) clone() *Pot {
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	return &Pot{
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		pin:  t.pin,
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		size: t.size,
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		po:   t.po,
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		bins: t.bins,
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	}
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}
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func add(t *Pot, val Val, pof Pof) (*Pot, int, bool) {
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	var r *Pot
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	if t == nil || t.pin == nil {
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		r = t.clone()
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		r.pin = val
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		r.size++
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		return r, 0, false
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	}
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	po, found := pof(t.pin, val, t.po)
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	if found {
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		r = t.clone()
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		r.pin = val
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		return r, po, true
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	}
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	var p *Pot
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	var i, j int
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	size := t.size
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	for i < len(t.bins) {
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		n := t.bins[i]
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		if n.po == po {
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			p, _, found = add(n, val, pof)
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			if !found {
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				size++
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			}
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			j++
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			break
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		}
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		if n.po > po {
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			break
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		}
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		i++
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		j++
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	}
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	if p == nil {
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		size++
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		p = &Pot{
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			pin:  val,
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			size: 1,
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			po:   po,
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		}
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	}
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	bins := append([]*Pot{}, t.bins[:i]...)
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	bins = append(bins, p)
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	bins = append(bins, t.bins[j:]...)
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	r = &Pot{
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		pin:  t.pin,
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		size: size,
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		po:   t.po,
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		bins: bins,
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	}
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	return r, po, found
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}
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// Remove called on (v) deletes v from the Pot and returns
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// the proximity order of v and a boolean value indicating
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// if the value was found
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// Remove called on (t, v) returns a new Pot that contains all the elements of t
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// minus the value v, using the applicative remove
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// the second return value is the proximity order of the inserted element
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// the third is boolean indicating if the item was found
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func Remove(t *Pot, v Val, pof Pof) (*Pot, int, bool) {
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	return remove(t, v, pof)
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}
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func remove(t *Pot, val Val, pof Pof) (r *Pot, po int, found bool) {
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	size := t.size
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	po, found = pof(t.pin, val, t.po)
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	if found {
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		size--
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		if size == 0 {
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			r = &Pot{
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				po: t.po,
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			}
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			return r, po, true
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		}
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		i := len(t.bins) - 1
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		last := t.bins[i]
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		r = &Pot{
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			pin:  last.pin,
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			bins: append(t.bins[:i], last.bins...),
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			size: size,
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			po:   t.po,
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		}
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		return r, t.po, true
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	}
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	var p *Pot
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	var i, j int
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	for i < len(t.bins) {
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		n := t.bins[i]
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		if n.po == po {
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			p, po, found = remove(n, val, pof)
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			if found {
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				size--
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			}
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			j++
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			break
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		}
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		if n.po > po {
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			return t, po, false
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		}
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		i++
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		j++
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	}
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	bins := t.bins[:i]
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	if p != nil && p.pin != nil {
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		bins = append(bins, p)
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	}
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	bins = append(bins, t.bins[j:]...)
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	r = &Pot{
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		pin:  val,
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		size: size,
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		po:   t.po,
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		bins: bins,
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	}
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	return r, po, found
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}
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// Swap called on (k, f) looks up the item at k
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// and applies the function f to the value v at k or to nil if the item is not found
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// if f(v) returns nil, the element is removed
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// if f(v) returns v' <> v then v' is inserted into the Pot
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// if (v) == v the Pot is not changed
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// it panics if Pof(f(v), k) show that v' and v are not key-equal
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func Swap(t *Pot, k Val, pof Pof, f func(v Val) Val) (r *Pot, po int, found bool, change bool) {
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	var val Val
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	if t.pin == nil {
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		val = f(nil)
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		if val == nil {
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			return nil, 0, false, false
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		}
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		return NewPot(val, t.po), 0, false, true
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	}
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	size := t.size
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	po, found = pof(k, t.pin, t.po)
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	if found {
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		val = f(t.pin)
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		// remove element
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		if val == nil {
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			size--
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			if size == 0 {
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				r = &Pot{
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					po: t.po,
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				}
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				// return empty pot
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				return r, po, true, true
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			}
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			// actually remove pin, by merging last bin
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			i := len(t.bins) - 1
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			last := t.bins[i]
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			r = &Pot{
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				pin:  last.pin,
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				bins: append(t.bins[:i], last.bins...),
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				size: size,
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				po:   t.po,
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			}
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			return r, po, true, true
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		}
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		// element found but no change
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		if val == t.pin {
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			return t, po, true, false
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		}
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		// actually modify the pinned element, but no change in structure
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		r = t.clone()
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		r.pin = val
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		return r, po, true, true
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	}
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	// recursive step
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	var p *Pot
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	n, i := t.getPos(po)
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	if n != nil {
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		p, po, found, change = Swap(n, k, pof, f)
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		// recursive no change
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		if !change {
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			return t, po, found, false
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		}
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		// recursive change
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		bins := append([]*Pot{}, t.bins[:i]...)
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		if p.size == 0 {
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			size--
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		} else {
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			size += p.size - n.size
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			bins = append(bins, p)
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		}
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		i++
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		if i < len(t.bins) {
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			bins = append(bins, t.bins[i:]...)
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		}
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		r = t.clone()
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		r.bins = bins
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		r.size = size
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		return r, po, found, true
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	}
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	// key does not exist
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	val = f(nil)
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	if val == nil {
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		// and it should not be created
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		return t, po, false, false
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	}
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	// otherwise check val if equal to k
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	if _, eq := pof(val, k, po); !eq {
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		panic("invalid value")
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	}
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	///
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	size++
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	p = &Pot{
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		pin:  val,
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		size: 1,
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		po:   po,
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	}
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	bins := append([]*Pot{}, t.bins[:i]...)
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	bins = append(bins, p)
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	if i < len(t.bins) {
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		bins = append(bins, t.bins[i:]...)
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	}
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	r = t.clone()
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	r.bins = bins
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	r.size = size
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	return r, po, found, true
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}
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// Union called on (t0, t1, pof) returns the union of t0 and t1
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// calculates the union using the applicative union
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// the second return value is the number of common elements
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func Union(t0, t1 *Pot, pof Pof) (*Pot, int) {
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	return union(t0, t1, pof)
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}
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func union(t0, t1 *Pot, pof Pof) (*Pot, int) {
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	if t0 == nil || t0.size == 0 {
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		return t1, 0
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	}
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	if t1 == nil || t1.size == 0 {
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		return t0, 0
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	}
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	var pin Val
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	var bins []*Pot
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	var mis []int
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	wg := &sync.WaitGroup{}
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	wg.Add(1)
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	pin0 := t0.pin
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	pin1 := t1.pin
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	bins0 := t0.bins
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	bins1 := t1.bins
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	var i0, i1 int
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	var common int
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	po, eq := pof(pin0, pin1, 0)
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	for {
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		l0 := len(bins0)
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		l1 := len(bins1)
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		var n0, n1 *Pot
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		var p0, p1 int
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		var a0, a1 bool
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		for {
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			if !a0 && i0 < l0 && bins0[i0] != nil && bins0[i0].po <= po {
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				n0 = bins0[i0]
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				p0 = n0.po
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				a0 = p0 == po
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			} else {
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				a0 = true
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			}
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			if !a1 && i1 < l1 && bins1[i1] != nil && bins1[i1].po <= po {
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				n1 = bins1[i1]
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				p1 = n1.po
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				a1 = p1 == po
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			} else {
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				a1 = true
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			}
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			if a0 && a1 {
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				break
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			}
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			switch {
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			case (p0 < p1 || a1) && !a0:
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				bins = append(bins, n0)
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				i0++
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				n0 = nil
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			case (p1 < p0 || a0) && !a1:
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				bins = append(bins, n1)
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				i1++
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				n1 = nil
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			case p1 < po:
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				bl := len(bins)
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				bins = append(bins, nil)
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				ml := len(mis)
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				mis = append(mis, 0)
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				// wg.Add(1)
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				// go func(b, m int, m0, m1 *Pot) {
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				// 	defer wg.Done()
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				// bins[b], mis[m] = union(m0, m1, pof)
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				// }(bl, ml, n0, n1)
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				bins[bl], mis[ml] = union(n0, n1, pof)
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				i0++
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				i1++
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				n0 = nil
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				n1 = nil
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			}
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		}
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		if eq {
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			common++
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			pin = pin1
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			break
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		}
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		i := i0
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		if len(bins0) > i && bins0[i].po == po {
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			i++
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		}
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						|
		var size0 int
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		for _, n := range bins0[i:] {
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			size0 += n.size
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		}
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		np := &Pot{
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			pin:  pin0,
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			bins: bins0[i:],
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			size: size0 + 1,
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			po:   po,
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		}
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						|
 | 
						|
		bins2 := []*Pot{np}
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						|
		if n0 == nil {
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			pin0 = pin1
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						|
			po = maxkeylen + 1
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						|
			eq = true
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						|
			common--
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						|
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						|
		} else {
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						|
			bins2 = append(bins2, n0.bins...)
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						|
			pin0 = pin1
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						|
			pin1 = n0.pin
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						|
			po, eq = pof(pin0, pin1, n0.po)
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						|
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		}
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		bins0 = bins1
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						|
		bins1 = bins2
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						|
		i0 = i1
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		i1 = 0
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						|
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	}
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						|
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						|
	wg.Done()
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						|
	wg.Wait()
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						|
	for _, c := range mis {
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						|
		common += c
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						|
	}
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						|
	n := &Pot{
 | 
						|
		pin:  pin,
 | 
						|
		bins: bins,
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						|
		size: t0.size + t1.size - common,
 | 
						|
		po:   t0.po,
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						|
	}
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	return n, common
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						|
}
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						|
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// Each called with (f) is a synchronous iterator over the bins of a node
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						|
// respecting an ordering
 | 
						|
// proximity > pinnedness
 | 
						|
func (t *Pot) Each(f func(Val, int) bool) bool {
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	return t.each(f)
 | 
						|
}
 | 
						|
 | 
						|
func (t *Pot) each(f func(Val, int) bool) bool {
 | 
						|
	var next bool
 | 
						|
	for _, n := range t.bins {
 | 
						|
		if n == nil {
 | 
						|
			return true
 | 
						|
		}
 | 
						|
		next = n.each(f)
 | 
						|
		if !next {
 | 
						|
			return false
 | 
						|
		}
 | 
						|
	}
 | 
						|
	if t.size == 0 {
 | 
						|
		return false
 | 
						|
	}
 | 
						|
	return f(t.pin, t.po)
 | 
						|
}
 | 
						|
 | 
						|
// EachFrom called with (f, start) is a synchronous iterator over the elements of a Pot
 | 
						|
// within the inclusive range starting from proximity order start
 | 
						|
// the function argument is passed the value and the proximity order wrt the root pin
 | 
						|
// it does NOT include the pinned item of the root
 | 
						|
// respecting an ordering
 | 
						|
// proximity > pinnedness
 | 
						|
// the iteration ends if the function return false or there are no more elements
 | 
						|
// end of a po range can be implemented since po is passed to the function
 | 
						|
func (t *Pot) EachFrom(f func(Val, int) bool, po int) bool {
 | 
						|
	return t.eachFrom(f, po)
 | 
						|
}
 | 
						|
 | 
						|
func (t *Pot) eachFrom(f func(Val, int) bool, po int) bool {
 | 
						|
	var next bool
 | 
						|
	_, lim := t.getPos(po)
 | 
						|
	for i := lim; i < len(t.bins); i++ {
 | 
						|
		n := t.bins[i]
 | 
						|
		next = n.each(f)
 | 
						|
		if !next {
 | 
						|
			return false
 | 
						|
		}
 | 
						|
	}
 | 
						|
	return f(t.pin, t.po)
 | 
						|
}
 | 
						|
 | 
						|
// EachBin iterates over bins of the pivot node and offers iterators to the caller on each
 | 
						|
// subtree passing the proximity order and the size
 | 
						|
// the iteration continues until the function's return value is false
 | 
						|
// or there are no more subtries
 | 
						|
func (t *Pot) EachBin(val Val, pof Pof, po int, f func(int, int, func(func(val Val, i int) bool) bool) bool) {
 | 
						|
	t.eachBin(val, pof, po, f)
 | 
						|
}
 | 
						|
 | 
						|
func (t *Pot) eachBin(val Val, pof Pof, po int, f func(int, int, func(func(val Val, i int) bool) bool) bool) {
 | 
						|
	if t == nil || t.size == 0 {
 | 
						|
		return
 | 
						|
	}
 | 
						|
	spr, _ := pof(t.pin, val, t.po)
 | 
						|
	_, lim := t.getPos(spr)
 | 
						|
	var size int
 | 
						|
	var n *Pot
 | 
						|
	for i := 0; i < lim; i++ {
 | 
						|
		n = t.bins[i]
 | 
						|
		size += n.size
 | 
						|
		if n.po < po {
 | 
						|
			continue
 | 
						|
		}
 | 
						|
		if !f(n.po, n.size, n.each) {
 | 
						|
			return
 | 
						|
		}
 | 
						|
	}
 | 
						|
	if lim == len(t.bins) {
 | 
						|
		if spr >= po {
 | 
						|
			f(spr, 1, func(g func(Val, int) bool) bool {
 | 
						|
				return g(t.pin, spr)
 | 
						|
			})
 | 
						|
		}
 | 
						|
		return
 | 
						|
	}
 | 
						|
 | 
						|
	n = t.bins[lim]
 | 
						|
 | 
						|
	spo := spr
 | 
						|
	if n.po == spr {
 | 
						|
		spo++
 | 
						|
		size += n.size
 | 
						|
	}
 | 
						|
	if spr >= po {
 | 
						|
		if !f(spr, t.size-size, func(g func(Val, int) bool) bool {
 | 
						|
			return t.eachFrom(func(v Val, j int) bool {
 | 
						|
				return g(v, spr)
 | 
						|
			}, spo)
 | 
						|
		}) {
 | 
						|
			return
 | 
						|
		}
 | 
						|
	}
 | 
						|
	if n.po == spr {
 | 
						|
		n.eachBin(val, pof, po, f)
 | 
						|
	}
 | 
						|
 | 
						|
}
 | 
						|
 | 
						|
// EachNeighbour is a synchronous iterator over neighbours of any target val
 | 
						|
// the order of elements retrieved reflect proximity order to the target
 | 
						|
// TODO: add maximum proxbin to start range of iteration
 | 
						|
func (t *Pot) EachNeighbour(val Val, pof Pof, f func(Val, int) bool) bool {
 | 
						|
	return t.eachNeighbour(val, pof, f)
 | 
						|
}
 | 
						|
 | 
						|
func (t *Pot) eachNeighbour(val Val, pof Pof, f func(Val, int) bool) bool {
 | 
						|
	if t == nil || t.size == 0 {
 | 
						|
		return false
 | 
						|
	}
 | 
						|
	var next bool
 | 
						|
	l := len(t.bins)
 | 
						|
	var n *Pot
 | 
						|
	ir := l
 | 
						|
	il := l
 | 
						|
	po, eq := pof(t.pin, val, t.po)
 | 
						|
	if !eq {
 | 
						|
		n, il = t.getPos(po)
 | 
						|
		if n != nil {
 | 
						|
			next = n.eachNeighbour(val, pof, f)
 | 
						|
			if !next {
 | 
						|
				return false
 | 
						|
			}
 | 
						|
			ir = il
 | 
						|
		} else {
 | 
						|
			ir = il - 1
 | 
						|
		}
 | 
						|
	}
 | 
						|
 | 
						|
	next = f(t.pin, po)
 | 
						|
	if !next {
 | 
						|
		return false
 | 
						|
	}
 | 
						|
 | 
						|
	for i := l - 1; i > ir; i-- {
 | 
						|
		next = t.bins[i].each(func(v Val, _ int) bool {
 | 
						|
			return f(v, po)
 | 
						|
		})
 | 
						|
		if !next {
 | 
						|
			return false
 | 
						|
		}
 | 
						|
	}
 | 
						|
 | 
						|
	for i := il - 1; i >= 0; i-- {
 | 
						|
		n := t.bins[i]
 | 
						|
		next = n.each(func(v Val, _ int) bool {
 | 
						|
			return f(v, n.po)
 | 
						|
		})
 | 
						|
		if !next {
 | 
						|
			return false
 | 
						|
		}
 | 
						|
	}
 | 
						|
	return true
 | 
						|
}
 | 
						|
 | 
						|
// EachNeighbourAsync called on (val, max, maxPos, f, wait) is an asynchronous iterator
 | 
						|
// over elements not closer than maxPos wrt val.
 | 
						|
// val does not need to be match an element of the Pot, but if it does, and
 | 
						|
// maxPos is keylength than it is included in the iteration
 | 
						|
// Calls to f are parallelised, the order of calls is undefined.
 | 
						|
// proximity order is respected in that there is no element in the Pot that
 | 
						|
// is not visited if a closer node is visited.
 | 
						|
// The iteration is finished when max number of nearest nodes is visited
 | 
						|
// or if the entire there are no nodes not closer than maxPos that is not visited
 | 
						|
// if wait is true, the iterator returns only if all calls to f are finished
 | 
						|
// TODO: implement minPos for proper prox range iteration
 | 
						|
func (t *Pot) EachNeighbourAsync(val Val, pof Pof, max int, maxPos int, f func(Val, int), wait bool) {
 | 
						|
	if max > t.size {
 | 
						|
		max = t.size
 | 
						|
	}
 | 
						|
	var wg *sync.WaitGroup
 | 
						|
	if wait {
 | 
						|
		wg = &sync.WaitGroup{}
 | 
						|
	}
 | 
						|
	t.eachNeighbourAsync(val, pof, max, maxPos, f, wg)
 | 
						|
	if wait {
 | 
						|
		wg.Wait()
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
func (t *Pot) eachNeighbourAsync(val Val, pof Pof, max int, maxPos int, f func(Val, int), wg *sync.WaitGroup) (extra int) {
 | 
						|
	l := len(t.bins)
 | 
						|
 | 
						|
	po, eq := pof(t.pin, val, t.po)
 | 
						|
 | 
						|
	// if po is too close, set the pivot branch (pom) to maxPos
 | 
						|
	pom := po
 | 
						|
	if pom > maxPos {
 | 
						|
		pom = maxPos
 | 
						|
	}
 | 
						|
	n, il := t.getPos(pom)
 | 
						|
	ir := il
 | 
						|
	// if pivot branch exists and po is not too close, iterate on the pivot branch
 | 
						|
	if pom == po {
 | 
						|
		if n != nil {
 | 
						|
 | 
						|
			m := n.size
 | 
						|
			if max < m {
 | 
						|
				m = max
 | 
						|
			}
 | 
						|
			max -= m
 | 
						|
 | 
						|
			extra = n.eachNeighbourAsync(val, pof, m, maxPos, f, wg)
 | 
						|
 | 
						|
		} else {
 | 
						|
			if !eq {
 | 
						|
				ir--
 | 
						|
			}
 | 
						|
		}
 | 
						|
	} else {
 | 
						|
		extra++
 | 
						|
		max--
 | 
						|
		if n != nil {
 | 
						|
			il++
 | 
						|
		}
 | 
						|
		// before checking max, add up the extra elements
 | 
						|
		// on the close branches that are skipped (if po is too close)
 | 
						|
		for i := l - 1; i >= il; i-- {
 | 
						|
			s := t.bins[i]
 | 
						|
			m := s.size
 | 
						|
			if max < m {
 | 
						|
				m = max
 | 
						|
			}
 | 
						|
			max -= m
 | 
						|
			extra += m
 | 
						|
		}
 | 
						|
	}
 | 
						|
 | 
						|
	var m int
 | 
						|
	if pom == po {
 | 
						|
 | 
						|
		m, max, extra = need(1, max, extra)
 | 
						|
		if m <= 0 {
 | 
						|
			return
 | 
						|
		}
 | 
						|
 | 
						|
		if wg != nil {
 | 
						|
			wg.Add(1)
 | 
						|
		}
 | 
						|
		go func() {
 | 
						|
			if wg != nil {
 | 
						|
				defer wg.Done()
 | 
						|
			}
 | 
						|
			f(t.pin, po)
 | 
						|
		}()
 | 
						|
 | 
						|
		// otherwise iterats
 | 
						|
		for i := l - 1; i > ir; i-- {
 | 
						|
			n := t.bins[i]
 | 
						|
 | 
						|
			m, max, extra = need(n.size, max, extra)
 | 
						|
			if m <= 0 {
 | 
						|
				return
 | 
						|
			}
 | 
						|
 | 
						|
			if wg != nil {
 | 
						|
				wg.Add(m)
 | 
						|
			}
 | 
						|
			go func(pn *Pot, pm int) {
 | 
						|
				pn.each(func(v Val, _ int) bool {
 | 
						|
					if wg != nil {
 | 
						|
						defer wg.Done()
 | 
						|
					}
 | 
						|
					f(v, po)
 | 
						|
					pm--
 | 
						|
					return pm > 0
 | 
						|
				})
 | 
						|
			}(n, m)
 | 
						|
 | 
						|
		}
 | 
						|
	}
 | 
						|
 | 
						|
	// iterate branches that are farther tham pom with their own po
 | 
						|
	for i := il - 1; i >= 0; i-- {
 | 
						|
		n := t.bins[i]
 | 
						|
		// the first time max is less than the size of the entire branch
 | 
						|
		// wait for the pivot thread to release extra elements
 | 
						|
		m, max, extra = need(n.size, max, extra)
 | 
						|
		if m <= 0 {
 | 
						|
			return
 | 
						|
		}
 | 
						|
 | 
						|
		if wg != nil {
 | 
						|
			wg.Add(m)
 | 
						|
		}
 | 
						|
		go func(pn *Pot, pm int) {
 | 
						|
			pn.each(func(v Val, _ int) bool {
 | 
						|
				if wg != nil {
 | 
						|
					defer wg.Done()
 | 
						|
				}
 | 
						|
				f(v, pn.po)
 | 
						|
				pm--
 | 
						|
				return pm > 0
 | 
						|
			})
 | 
						|
		}(n, m)
 | 
						|
 | 
						|
	}
 | 
						|
	return max + extra
 | 
						|
}
 | 
						|
 | 
						|
// getPos called on (n) returns the forking node at PO n and its index if it exists
 | 
						|
// otherwise nil
 | 
						|
// caller is supposed to hold the lock
 | 
						|
func (t *Pot) getPos(po int) (n *Pot, i int) {
 | 
						|
	for i, n = range t.bins {
 | 
						|
		if po > n.po {
 | 
						|
			continue
 | 
						|
		}
 | 
						|
		if po < n.po {
 | 
						|
			return nil, i
 | 
						|
		}
 | 
						|
		return n, i
 | 
						|
	}
 | 
						|
	return nil, len(t.bins)
 | 
						|
}
 | 
						|
 | 
						|
// need called on (m, max, extra) uses max m out of extra, and then max
 | 
						|
// if needed, returns the adjusted counts
 | 
						|
func need(m, max, extra int) (int, int, int) {
 | 
						|
	if m <= extra {
 | 
						|
		return m, max, extra - m
 | 
						|
	}
 | 
						|
	max += extra - m
 | 
						|
	if max <= 0 {
 | 
						|
		return m + max, 0, 0
 | 
						|
	}
 | 
						|
	return m, max, 0
 | 
						|
}
 | 
						|
 | 
						|
func (t *Pot) String() string {
 | 
						|
	return t.sstring("")
 | 
						|
}
 | 
						|
 | 
						|
func (t *Pot) sstring(indent string) string {
 | 
						|
	if t == nil {
 | 
						|
		return "<nil>"
 | 
						|
	}
 | 
						|
	var s string
 | 
						|
	indent += "  "
 | 
						|
	s += fmt.Sprintf("%v%v (%v) %v \n", indent, t.pin, t.po, t.size)
 | 
						|
	for _, n := range t.bins {
 | 
						|
		s += fmt.Sprintf("%v%v\n", indent, n.sstring(indent))
 | 
						|
	}
 | 
						|
	return s
 | 
						|
}
 |