go avlint32 源码
golang avlint32 代码
文件路径：/src/cmd/compile/internal/abt/avlint32.go
// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package abt
import (
"fmt"
"strconv"
)
const (
LEAF_HEIGHT = 1
ZERO_HEIGHT = 0
NOT_KEY32 = int32(-0x80000000)
)
// T is the exported applicative balanced tree data type.
// A T can be used as a value; updates to one copy of the value
// do not change other copies.
type T struct {
root *node32
size int
}
// node32 is the internal tree node data type
type node32 struct {
// Standard conventions hold for left = smaller, right = larger
left, right *node32
data interface{}
key int32
height_ int8
}
func makeNode(key int32) *node32 {
return &node32{key: key, height_: LEAF_HEIGHT}
}
// IsSingle returns true iff t is empty.
func (t *T) IsEmpty() bool {
return t.root == nil
}
// IsSingle returns true iff t is a singleton (leaf).
func (t *T) IsSingle() bool {
return t.root != nil && t.root.isLeaf()
}
// VisitInOrder applies f to the key and data pairs in t,
// with keys ordered from smallest to largest.
func (t *T) VisitInOrder(f func(int32, interface{})) {
if t.root == nil {
return
}
t.root.visitInOrder(f)
}
func (n *node32) nilOrData() interface{} {
if n == nil {
return nil
}
return n.data
}
func (n *node32) nilOrKeyAndData() (k int32, d interface{}) {
if n == nil {
k = NOT_KEY32
d = nil
} else {
k = n.key
d = n.data
}
return
}
func (n *node32) height() int8 {
if n == nil {
return 0
}
return n.height_
}
// Find returns the data associated with x in the tree, or
// nil if x is not in the tree.
func (t *T) Find(x int32) interface{} {
return t.root.find(x).nilOrData()
}
// Insert either adds x to the tree if x was not previously
// a key in the tree, or updates the data for x in the tree if
// x was already a key in the tree. The previous data associated
// with x is returned, and is nil if x was not previously a
// key in the tree.
func (t *T) Insert(x int32, data interface{}) interface{} {
if x == NOT_KEY32 {
panic("Cannot use sentinel value -0x80000000 as key")
}
n := t.root
var newroot *node32
var o *node32
if n == nil {
n = makeNode(x)
newroot = n
} else {
newroot, n, o = n.aInsert(x)
}
var r interface{}
if o != nil {
r = o.data
} else {
t.size++
}
n.data = data
t.root = newroot
return r
}
func (t *T) Copy() *T {
u := *t
return &u
}
func (t *T) Delete(x int32) interface{} {
n := t.root
if n == nil {
return nil
}
d, s := n.aDelete(x)
if d == nil {
return nil
}
t.root = s
t.size--
return d.data
}
func (t *T) DeleteMin() (int32, interface{}) {
n := t.root
if n == nil {
return NOT_KEY32, nil
}
d, s := n.aDeleteMin()
if d == nil {
return NOT_KEY32, nil
}
t.root = s
t.size--
return d.key, d.data
}
func (t *T) DeleteMax() (int32, interface{}) {
n := t.root
if n == nil {
return NOT_KEY32, nil
}
d, s := n.aDeleteMax()
if d == nil {
return NOT_KEY32, nil
}
t.root = s
t.size--
return d.key, d.data
}
func (t *T) Size() int {
return t.size
}
// Intersection returns the intersection of t and u, where the result
// data for any common keys is given by f(t's data, u's data) -- f need
// not be symmetric. If f returns nil, then the key and data are not
// added to the result. If f itself is nil, then whatever value was
// already present in the smaller set is used.
func (t *T) Intersection(u *T, f func(x, y interface{}) interface{}) *T {
if t.Size() == 0 || u.Size() == 0 {
return &T{}
}
// For faster execution and less allocation, prefer t smaller, iterate over t.
if t.Size() <= u.Size() {
v := t.Copy()
for it := t.Iterator(); !it.Done(); {
k, d := it.Next()
e := u.Find(k)
if e == nil {
v.Delete(k)
continue
}
if f == nil {
continue
}
if c := f(d, e); c != d {
if c == nil {
v.Delete(k)
} else {
v.Insert(k, c)
}
}
}
return v
}
v := u.Copy()
for it := u.Iterator(); !it.Done(); {
k, e := it.Next()
d := t.Find(k)
if d == nil {
v.Delete(k)
continue
}
if f == nil {
continue
}
if c := f(d, e); c != d {
if c == nil {
v.Delete(k)
} else {
v.Insert(k, c)
}
}
}
return v
}
// Union returns the union of t and u, where the result data for any common keys
// is given by f(t's data, u's data) -- f need not be symmetric. If f returns nil,
// then the key and data are not added to the result. If f itself is nil, then
// whatever value was already present in the larger set is used.
func (t *T) Union(u *T, f func(x, y interface{}) interface{}) *T {
if t.Size() == 0 {
return u
}
if u.Size() == 0 {
return t
}
if t.Size() >= u.Size() {
v := t.Copy()
for it := u.Iterator(); !it.Done(); {
k, e := it.Next()
d := t.Find(k)
if d == nil {
v.Insert(k, e)
continue
}
if f == nil {
continue
}
if c := f(d, e); c != d {
if c == nil {
v.Delete(k)
} else {
v.Insert(k, c)
}
}
}
return v
}
v := u.Copy()
for it := t.Iterator(); !it.Done(); {
k, d := it.Next()
e := u.Find(k)
if e == nil {
v.Insert(k, d)
continue
}
if f == nil {
continue
}
if c := f(d, e); c != d {
if c == nil {
v.Delete(k)
} else {
v.Insert(k, c)
}
}
}
return v
}
// Difference returns the difference of t and u, subject to the result
// of f applied to data corresponding to equal keys. If f returns nil
// (or if f is nil) then the key+data are excluded, as usual. If f
// returns not-nil, then that key+data pair is inserted. instead.
func (t *T) Difference(u *T, f func(x, y interface{}) interface{}) *T {
if t.Size() == 0 {
return &T{}
}
if u.Size() == 0 {
return t
}
v := t.Copy()
for it := t.Iterator(); !it.Done(); {
k, d := it.Next()
e := u.Find(k)
if e != nil {
if f == nil {
v.Delete(k)
continue
}
c := f(d, e)
if c == nil {
v.Delete(k)
continue
}
if c != d {
v.Insert(k, c)
}
}
}
return v
}
func (t *T) Iterator() Iterator {
return Iterator{it: t.root.iterator()}
}
func (t *T) Equals(u *T) bool {
if t == u {
return true
}
if t.Size() != u.Size() {
return false
}
return t.root.equals(u.root)
}
// This doesn't build with go1.4, sigh
// func (t *T) String() string {
// var b strings.Builder
// first := true
// for it := t.Iterator(); !it.IsEmpty(); {
// k, v := it.Next()
// if first {
// first = false
// } else {
// b.WriteString("; ")
// }
// b.WriteString(strconv.FormatInt(int64(k), 10))
// b.WriteString(":")
// b.WriteString(v.String())
// }
// return b.String()
// }
func (t *T) String() string {
var b string
first := true
for it := t.Iterator(); !it.Done(); {
k, v := it.Next()
if first {
first = false
} else {
b += ("; ")
}
b += (strconv.FormatInt(int64(k), 10))
b += (":")
b += fmt.Sprint(v)
}
return b
}
func (t *node32) equals(u *node32) bool {
if t == u {
return true
}
it, iu := t.iterator(), u.iterator()
for !it.done() && !iu.done() {
nt := it.next()
nu := iu.next()
if nt == nu {
continue
}
if nt.key != nu.key {
return false
}
if nt.data != nu.data {
return false
}
}
return it.done() == iu.done()
}
func (t *T) Equiv(u *T, eqv func(x, y interface{}) bool) bool {
if t == u {
return true
}
if t.Size() != u.Size() {
return false
}
return t.root.equiv(u.root, eqv)
}
func (t *node32) equiv(u *node32, eqv func(x, y interface{}) bool) bool {
if t == u {
return true
}
it, iu := t.iterator(), u.iterator()
for !it.done() && !iu.done() {
nt := it.next()
nu := iu.next()
if nt == nu {
continue
}
if nt.key != nu.key {
return false
}
if !eqv(nt.data, nu.data) {
return false
}
}
return it.done() == iu.done()
}
type iterator struct {
parents []*node32
}
type Iterator struct {
it iterator
}
func (it *Iterator) Next() (int32, interface{}) {
x := it.it.next()
if x == nil {
return NOT_KEY32, nil
}
return x.key, x.data
}
func (it *Iterator) Done() bool {
return len(it.it.parents) == 0
}
func (t *node32) iterator() iterator {
if t == nil {
return iterator{}
}
it := iterator{parents: make([]*node32, 0, int(t.height()))}
it.leftmost(t)
return it
}
func (it *iterator) leftmost(t *node32) {
for t != nil {
it.parents = append(it.parents, t)
t = t.left
}
}
func (it *iterator) done() bool {
return len(it.parents) == 0
}
func (it *iterator) next() *node32 {
l := len(it.parents)
if l == 0 {
return nil
}
x := it.parents[l-1] // return value
if x.right != nil {
it.leftmost(x.right)
return x
}
// discard visited top of parents
l--
it.parents = it.parents[:l]
y := x // y is known visited/returned
for l > 0 && y == it.parents[l-1].right {
y = it.parents[l-1]
l--
it.parents = it.parents[:l]
}
return x
}
// Min returns the minimum element of t.
// If t is empty, then (NOT_KEY32, nil) is returned.
func (t *T) Min() (k int32, d interface{}) {
return t.root.min().nilOrKeyAndData()
}
// Max returns the maximum element of t.
// If t is empty, then (NOT_KEY32, nil) is returned.
func (t *T) Max() (k int32, d interface{}) {
return t.root.max().nilOrKeyAndData()
}
// Glb returns the greatest-lower-bound-exclusive of x and the associated
// data. If x has no glb in the tree, then (NOT_KEY32, nil) is returned.
func (t *T) Glb(x int32) (k int32, d interface{}) {
return t.root.glb(x, false).nilOrKeyAndData()
}
// GlbEq returns the greatest-lower-bound-inclusive of x and the associated
// data. If x has no glbEQ in the tree, then (NOT_KEY32, nil) is returned.
func (t *T) GlbEq(x int32) (k int32, d interface{}) {
return t.root.glb(x, true).nilOrKeyAndData()
}
// Lub returns the least-upper-bound-exclusive of x and the associated
// data. If x has no lub in the tree, then (NOT_KEY32, nil) is returned.
func (t *T) Lub(x int32) (k int32, d interface{}) {
return t.root.lub(x, false).nilOrKeyAndData()
}
// LubEq returns the least-upper-bound-inclusive of x and the associated
// data. If x has no lubEq in the tree, then (NOT_KEY32, nil) is returned.
func (t *T) LubEq(x int32) (k int32, d interface{}) {
return t.root.lub(x, true).nilOrKeyAndData()
}
func (t *node32) isLeaf() bool {
return t.left == nil && t.right == nil && t.height_ == LEAF_HEIGHT
}
func (t *node32) visitInOrder(f func(int32, interface{})) {
if t.left != nil {
t.left.visitInOrder(f)
}
f(t.key, t.data)
if t.right != nil {
t.right.visitInOrder(f)
}
}
func (t *node32) find(key int32) *node32 {
for t != nil {
if key < t.key {
t = t.left
} else if key > t.key {
t = t.right
} else {
return t
}
}
return nil
}
func (t *node32) min() *node32 {
if t == nil {
return t
}
for t.left != nil {
t = t.left
}
return t
}
func (t *node32) max() *node32 {
if t == nil {
return t
}
for t.right != nil {
t = t.right
}
return t
}
func (t *node32) glb(key int32, allow_eq bool) *node32 {
var best *node32 = nil
for t != nil {
if key <= t.key {
if allow_eq && key == t.key {
return t
}
// t is too big, glb is to left.
t = t.left
} else {
// t is a lower bound, record it and seek a better one.
best = t
t = t.right
}
}
return best
}
func (t *node32) lub(key int32, allow_eq bool) *node32 {
var best *node32 = nil
for t != nil {
if key >= t.key {
if allow_eq && key == t.key {
return t
}
// t is too small, lub is to right.
t = t.right
} else {
// t is a upper bound, record it and seek a better one.
best = t
t = t.left
}
}
return best
}
func (t *node32) aInsert(x int32) (newroot, newnode, oldnode *node32) {
// oldnode default of nil is good, others should be assigned.
if x == t.key {
oldnode = t
newt := *t
newnode = &newt
newroot = newnode
return
}
if x < t.key {
if t.left == nil {
t = t.copy()
n := makeNode(x)
t.left = n
newnode = n
newroot = t
t.height_ = 2 // was balanced w/ 0, sibling is height 0 or 1
return
}
var new_l *node32
new_l, newnode, oldnode = t.left.aInsert(x)
t = t.copy()
t.left = new_l
if new_l.height() > 1+t.right.height() {
newroot = t.aLeftIsHigh(newnode)
} else {
t.height_ = 1 + max(t.left.height(), t.right.height())
newroot = t
}
} else { // x > t.key
if t.right == nil {
t = t.copy()
n := makeNode(x)
t.right = n
newnode = n
newroot = t
t.height_ = 2 // was balanced w/ 0, sibling is height 0 or 1
return
}
var new_r *node32
new_r, newnode, oldnode = t.right.aInsert(x)
t = t.copy()
t.right = new_r
if new_r.height() > 1+t.left.height() {
newroot = t.aRightIsHigh(newnode)
} else {
t.height_ = 1 + max(t.left.height(), t.right.height())
newroot = t
}
}
return
}
func (t *node32) aDelete(key int32) (deleted, newSubTree *node32) {
if t == nil {
return nil, nil
}
if key < t.key {
oh := t.left.height()
d, tleft := t.left.aDelete(key)
if tleft == t.left {
return d, t
}
return d, t.copy().aRebalanceAfterLeftDeletion(oh, tleft)
} else if key > t.key {
oh := t.right.height()
d, tright := t.right.aDelete(key)
if tright == t.right {
return d, t
}
return d, t.copy().aRebalanceAfterRightDeletion(oh, tright)
}
if t.height() == LEAF_HEIGHT {
return t, nil
}
// Interior delete by removing left.Max or right.Min,
// then swapping contents
if t.left.height() > t.right.height() {
oh := t.left.height()
d, tleft := t.left.aDeleteMax()
r := t
t = t.copy()
t.data, t.key = d.data, d.key
return r, t.aRebalanceAfterLeftDeletion(oh, tleft)
}
oh := t.right.height()
d, tright := t.right.aDeleteMin()
r := t
t = t.copy()
t.data, t.key = d.data, d.key
return r, t.aRebalanceAfterRightDeletion(oh, tright)
}
func (t *node32) aDeleteMin() (deleted, newSubTree *node32) {
if t == nil {
return nil, nil
}
if t.left == nil { // leaf or left-most
return t, t.right
}
oh := t.left.height()
d, tleft := t.left.aDeleteMin()
if tleft == t.left {
return d, t
}
return d, t.copy().aRebalanceAfterLeftDeletion(oh, tleft)
}
func (t *node32) aDeleteMax() (deleted, newSubTree *node32) {
if t == nil {
return nil, nil
}
if t.right == nil { // leaf or right-most
return t, t.left
}
oh := t.right.height()
d, tright := t.right.aDeleteMax()
if tright == t.right {
return d, t
}
return d, t.copy().aRebalanceAfterRightDeletion(oh, tright)
}
func (t *node32) aRebalanceAfterLeftDeletion(oldLeftHeight int8, tleft *node32) *node32 {
t.left = tleft
if oldLeftHeight == tleft.height() || oldLeftHeight == t.right.height() {
// this node is still balanced and its height is unchanged
return t
}
if oldLeftHeight > t.right.height() {
// left was larger
t.height_--
return t
}
// left height fell by 1 and it was already less than right height
t.right = t.right.copy()
return t.aRightIsHigh(nil)
}
func (t *node32) aRebalanceAfterRightDeletion(oldRightHeight int8, tright *node32) *node32 {
t.right = tright
if oldRightHeight == tright.height() || oldRightHeight == t.left.height() {
// this node is still balanced and its height is unchanged
return t
}
if oldRightHeight > t.left.height() {
// left was larger
t.height_--
return t
}
// right height fell by 1 and it was already less than left height
t.left = t.left.copy()
return t.aLeftIsHigh(nil)
}
// aRightIsHigh does rotations necessary to fix a high right child
// assume that t and t.right are already fresh copies.
func (t *node32) aRightIsHigh(newnode *node32) *node32 {
right := t.right
if right.right.height() < right.left.height() {
// double rotation
if newnode != right.left {
right.left = right.left.copy()
}
t.right = right.leftToRoot()
}
t = t.rightToRoot()
return t
}
// aLeftIsHigh does rotations necessary to fix a high left child
// assume that t and t.left are already fresh copies.
func (t *node32) aLeftIsHigh(newnode *node32) *node32 {
left := t.left
if left.left.height() < left.right.height() {
// double rotation
if newnode != left.right {
left.right = left.right.copy()
}
t.left = left.rightToRoot()
}
t = t.leftToRoot()
return t
}
// rightToRoot does that rotation, modifying t and t.right in the process.
func (t *node32) rightToRoot() *node32 {
// this
// left right
// rl rr
//
// becomes
//
// right
// this rr
// left rl
//
right := t.right
rl := right.left
right.left = t
// parent's child ptr fixed in caller
t.right = rl
t.height_ = 1 + max(rl.height(), t.left.height())
right.height_ = 1 + max(t.height(), right.right.height())
return right
}
// leftToRoot does that rotation, modifying t and t.left in the process.
func (t *node32) leftToRoot() *node32 {
// this
// left right
// ll lr
//
// becomes
//
// left
// ll this
// lr right
//
left := t.left
lr := left.right
left.right = t
// parent's child ptr fixed in caller
t.left = lr
t.height_ = 1 + max(lr.height(), t.right.height())
left.height_ = 1 + max(t.height(), left.left.height())
return left
}
func max(a, b int8) int8 {
if a > b {
return a
}
return b
}
func (t *node32) copy() *node32 {
u := *t
return &u
}
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