forked from cerc-io/ipld-eth-server
788 lines
16 KiB
Go
788 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 deletes element v from the Pot t and returns three parameters:
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// 1. new Pot that contains all the elements of t minus the element v;
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// 2. proximity order of the removed element v;
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// 3. boolean indicating whether 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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return &Pot{}, 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: 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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// 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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} 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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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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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{
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pin: pin,
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bins: bins,
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size: t0.size + t1.size - common,
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po: t0.po,
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}
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return n, common
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}
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// Each is a synchronous iterator over the elements of pot with function f.
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func (t *Pot) Each(f func(Val) bool) bool {
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return t.each(f)
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}
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// each is a synchronous iterator over the elements of pot with function f.
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// the iteration ends if the function return false or there are no more elements.
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func (t *Pot) each(f func(Val) bool) bool {
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if t == nil || t.size == 0 {
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return false
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}
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for _, n := range t.bins {
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if !n.each(f) {
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return false
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}
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}
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return f(t.pin)
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}
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// eachFrom is a synchronous iterator over the elements of pot with function f,
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// starting from certain proximity order po, which is passed as a second parameter.
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// the iteration ends if the function return false or there are no more elements.
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func (t *Pot) eachFrom(f func(Val) bool, po int) bool {
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if t == nil || t.size == 0 {
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return false
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}
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_, beg := t.getPos(po)
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for i := beg; i < len(t.bins); i++ {
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if !t.bins[i].each(f) {
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return false
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}
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}
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return f(t.pin)
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}
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// EachBin iterates over bins of the pivot node and offers iterators to the caller on each
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// subtree passing the proximity order and the size
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// the iteration continues until the function's return value is false
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// or there are no more subtries
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func (t *Pot) EachBin(val Val, pof Pof, po int, f func(int, int, func(func(val Val) bool) bool) bool) {
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t.eachBin(val, pof, po, f)
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}
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func (t *Pot) eachBin(val Val, pof Pof, po int, f func(int, int, func(func(val Val) bool) bool) bool) {
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if t == nil || t.size == 0 {
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return
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}
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spr, _ := pof(t.pin, val, t.po)
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_, lim := t.getPos(spr)
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var size int
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var n *Pot
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for i := 0; i < lim; i++ {
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n = t.bins[i]
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size += n.size
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if n.po < po {
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continue
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}
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if !f(n.po, n.size, n.each) {
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return
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}
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}
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if lim == len(t.bins) {
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if spr >= po {
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f(spr, 1, func(g func(Val) bool) bool {
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return g(t.pin)
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})
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}
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return
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}
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n = t.bins[lim]
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spo := spr
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if n.po == spr {
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spo++
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size += n.size
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}
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if spr >= po {
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if !f(spr, t.size-size, func(g func(Val) bool) bool {
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return t.eachFrom(func(v Val) bool {
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return g(v)
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}, spo)
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}) {
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return
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}
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}
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if n.po == spr {
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n.eachBin(val, pof, po, f)
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}
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}
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|
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// EachNeighbour is a synchronous iterator over neighbours of any target val
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// the order of elements retrieved reflect proximity order to the target
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// TODO: add maximum proxbin to start range of iteration
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func (t *Pot) EachNeighbour(val Val, pof Pof, f func(Val, int) bool) bool {
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return t.eachNeighbour(val, pof, f)
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}
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|
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func (t *Pot) eachNeighbour(val Val, pof Pof, f func(Val, int) bool) bool {
|
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if t == nil || t.size == 0 {
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return false
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}
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var next bool
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l := len(t.bins)
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var n *Pot
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ir := l
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il := l
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po, eq := pof(t.pin, val, t.po)
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if !eq {
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n, il = t.getPos(po)
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if n != nil {
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next = n.eachNeighbour(val, pof, f)
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if !next {
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return false
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}
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ir = il
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} else {
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ir = il - 1
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}
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}
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|
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next = f(t.pin, po)
|
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if !next {
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return false
|
|
}
|
|
|
|
for i := l - 1; i > ir; i-- {
|
|
next = t.bins[i].each(func(v Val) 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) 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) 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) 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
|
|
}
|