ceph-csi/vendor/github.com/antlr4-go/antlr/v4/prediction_context.go
Madhu Rajanna 5a66991bb3 rebase: update kubernetes to latest
updating the kubernetes release to the
latest in main go.mod

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
2024-08-20 08:17:01 +00:00

728 lines
21 KiB
Go

// Copyright (c) 2012-2022 The ANTLR Project. All rights reserved.
// Use of this file is governed by the BSD 3-clause license that
// can be found in the LICENSE.txt file in the project root.
package antlr
import (
"fmt"
"golang.org/x/exp/slices"
"strconv"
)
var _emptyPredictionContextHash int
func init() {
_emptyPredictionContextHash = murmurInit(1)
_emptyPredictionContextHash = murmurFinish(_emptyPredictionContextHash, 0)
}
func calculateEmptyHash() int {
return _emptyPredictionContextHash
}
const (
// BasePredictionContextEmptyReturnState represents {@code $} in an array in full context mode, $
// doesn't mean wildcard:
//
// $ + x = [$,x]
//
// Here,
//
// $ = EmptyReturnState
BasePredictionContextEmptyReturnState = 0x7FFFFFFF
)
// TODO: JI These are meant to be atomics - this does not seem to match the Java runtime here
//
//goland:noinspection GoUnusedGlobalVariable
var (
BasePredictionContextglobalNodeCount = 1
BasePredictionContextid = BasePredictionContextglobalNodeCount
)
const (
PredictionContextEmpty = iota
PredictionContextSingleton
PredictionContextArray
)
// PredictionContext is a go idiomatic implementation of PredictionContext that does not rty to
// emulate inheritance from Java, and can be used without an interface definition. An interface
// is not required because no user code will ever need to implement this interface.
type PredictionContext struct {
cachedHash int
pcType int
parentCtx *PredictionContext
returnState int
parents []*PredictionContext
returnStates []int
}
func NewEmptyPredictionContext() *PredictionContext {
nep := &PredictionContext{}
nep.cachedHash = calculateEmptyHash()
nep.pcType = PredictionContextEmpty
nep.returnState = BasePredictionContextEmptyReturnState
return nep
}
func NewBaseSingletonPredictionContext(parent *PredictionContext, returnState int) *PredictionContext {
pc := &PredictionContext{}
pc.pcType = PredictionContextSingleton
pc.returnState = returnState
pc.parentCtx = parent
if parent != nil {
pc.cachedHash = calculateHash(parent, returnState)
} else {
pc.cachedHash = calculateEmptyHash()
}
return pc
}
func SingletonBasePredictionContextCreate(parent *PredictionContext, returnState int) *PredictionContext {
if returnState == BasePredictionContextEmptyReturnState && parent == nil {
// someone can pass in the bits of an array ctx that mean $
return BasePredictionContextEMPTY
}
return NewBaseSingletonPredictionContext(parent, returnState)
}
func NewArrayPredictionContext(parents []*PredictionContext, returnStates []int) *PredictionContext {
// Parent can be nil only if full ctx mode and we make an array
// from {@link //EMPTY} and non-empty. We merge {@link //EMPTY} by using
// nil parent and
// returnState == {@link //EmptyReturnState}.
hash := murmurInit(1)
for _, parent := range parents {
hash = murmurUpdate(hash, parent.Hash())
}
for _, returnState := range returnStates {
hash = murmurUpdate(hash, returnState)
}
hash = murmurFinish(hash, len(parents)<<1)
nec := &PredictionContext{}
nec.cachedHash = hash
nec.pcType = PredictionContextArray
nec.parents = parents
nec.returnStates = returnStates
return nec
}
func (p *PredictionContext) Hash() int {
return p.cachedHash
}
func (p *PredictionContext) Equals(other Collectable[*PredictionContext]) bool {
switch p.pcType {
case PredictionContextEmpty:
otherP := other.(*PredictionContext)
return other == nil || otherP == nil || otherP.isEmpty()
case PredictionContextSingleton:
return p.SingletonEquals(other)
case PredictionContextArray:
return p.ArrayEquals(other)
}
return false
}
func (p *PredictionContext) ArrayEquals(o Collectable[*PredictionContext]) bool {
if o == nil {
return false
}
other := o.(*PredictionContext)
if other == nil || other.pcType != PredictionContextArray {
return false
}
if p.cachedHash != other.Hash() {
return false // can't be same if hash is different
}
// Must compare the actual array elements and not just the array address
//
return slices.Equal(p.returnStates, other.returnStates) &&
slices.EqualFunc(p.parents, other.parents, func(x, y *PredictionContext) bool {
return x.Equals(y)
})
}
func (p *PredictionContext) SingletonEquals(other Collectable[*PredictionContext]) bool {
if other == nil {
return false
}
otherP := other.(*PredictionContext)
if otherP == nil {
return false
}
if p.cachedHash != otherP.Hash() {
return false // Can't be same if hash is different
}
if p.returnState != otherP.getReturnState(0) {
return false
}
// Both parents must be nil if one is
if p.parentCtx == nil {
return otherP.parentCtx == nil
}
return p.parentCtx.Equals(otherP.parentCtx)
}
func (p *PredictionContext) GetParent(i int) *PredictionContext {
switch p.pcType {
case PredictionContextEmpty:
return nil
case PredictionContextSingleton:
return p.parentCtx
case PredictionContextArray:
return p.parents[i]
}
return nil
}
func (p *PredictionContext) getReturnState(i int) int {
switch p.pcType {
case PredictionContextArray:
return p.returnStates[i]
default:
return p.returnState
}
}
func (p *PredictionContext) GetReturnStates() []int {
switch p.pcType {
case PredictionContextArray:
return p.returnStates
default:
return []int{p.returnState}
}
}
func (p *PredictionContext) length() int {
switch p.pcType {
case PredictionContextArray:
return len(p.returnStates)
default:
return 1
}
}
func (p *PredictionContext) hasEmptyPath() bool {
switch p.pcType {
case PredictionContextSingleton:
return p.returnState == BasePredictionContextEmptyReturnState
}
return p.getReturnState(p.length()-1) == BasePredictionContextEmptyReturnState
}
func (p *PredictionContext) String() string {
switch p.pcType {
case PredictionContextEmpty:
return "$"
case PredictionContextSingleton:
var up string
if p.parentCtx == nil {
up = ""
} else {
up = p.parentCtx.String()
}
if len(up) == 0 {
if p.returnState == BasePredictionContextEmptyReturnState {
return "$"
}
return strconv.Itoa(p.returnState)
}
return strconv.Itoa(p.returnState) + " " + up
case PredictionContextArray:
if p.isEmpty() {
return "[]"
}
s := "["
for i := 0; i < len(p.returnStates); i++ {
if i > 0 {
s = s + ", "
}
if p.returnStates[i] == BasePredictionContextEmptyReturnState {
s = s + "$"
continue
}
s = s + strconv.Itoa(p.returnStates[i])
if !p.parents[i].isEmpty() {
s = s + " " + p.parents[i].String()
} else {
s = s + "nil"
}
}
return s + "]"
default:
return "unknown"
}
}
func (p *PredictionContext) isEmpty() bool {
switch p.pcType {
case PredictionContextEmpty:
return true
case PredictionContextArray:
// since EmptyReturnState can only appear in the last position, we
// don't need to verify that size==1
return p.returnStates[0] == BasePredictionContextEmptyReturnState
default:
return false
}
}
func (p *PredictionContext) Type() int {
return p.pcType
}
func calculateHash(parent *PredictionContext, returnState int) int {
h := murmurInit(1)
h = murmurUpdate(h, parent.Hash())
h = murmurUpdate(h, returnState)
return murmurFinish(h, 2)
}
// Convert a {@link RuleContext} tree to a {@link BasePredictionContext} graph.
// Return {@link //EMPTY} if {@code outerContext} is empty or nil.
// /
func predictionContextFromRuleContext(a *ATN, outerContext RuleContext) *PredictionContext {
if outerContext == nil {
outerContext = ParserRuleContextEmpty
}
// if we are in RuleContext of start rule, s, then BasePredictionContext
// is EMPTY. Nobody called us. (if we are empty, return empty)
if outerContext.GetParent() == nil || outerContext == ParserRuleContextEmpty {
return BasePredictionContextEMPTY
}
// If we have a parent, convert it to a BasePredictionContext graph
parent := predictionContextFromRuleContext(a, outerContext.GetParent().(RuleContext))
state := a.states[outerContext.GetInvokingState()]
transition := state.GetTransitions()[0]
return SingletonBasePredictionContextCreate(parent, transition.(*RuleTransition).followState.GetStateNumber())
}
func merge(a, b *PredictionContext, rootIsWildcard bool, mergeCache *JPCMap) *PredictionContext {
// Share same graph if both same
//
if a == b || a.Equals(b) {
return a
}
if a.pcType == PredictionContextSingleton && b.pcType == PredictionContextSingleton {
return mergeSingletons(a, b, rootIsWildcard, mergeCache)
}
// At least one of a or b is array
// If one is $ and rootIsWildcard, return $ as wildcard
if rootIsWildcard {
if a.isEmpty() {
return a
}
if b.isEmpty() {
return b
}
}
// Convert either Singleton or Empty to arrays, so that we can merge them
//
ara := convertToArray(a)
arb := convertToArray(b)
return mergeArrays(ara, arb, rootIsWildcard, mergeCache)
}
func convertToArray(pc *PredictionContext) *PredictionContext {
switch pc.Type() {
case PredictionContextEmpty:
return NewArrayPredictionContext([]*PredictionContext{}, []int{})
case PredictionContextSingleton:
return NewArrayPredictionContext([]*PredictionContext{pc.GetParent(0)}, []int{pc.getReturnState(0)})
default:
// Already an array
}
return pc
}
// mergeSingletons merges two Singleton [PredictionContext] instances.
//
// Stack tops equal, parents merge is same return left graph.
// <embed src="images/SingletonMerge_SameRootSamePar.svg"
// type="image/svg+xml"/></p>
//
// <p>Same stack top, parents differ merge parents giving array node, then
// remainders of those graphs. A new root node is created to point to the
// merged parents.<br>
// <embed src="images/SingletonMerge_SameRootDiffPar.svg"
// type="image/svg+xml"/></p>
//
// <p>Different stack tops pointing to same parent. Make array node for the
// root where both element in the root point to the same (original)
// parent.<br>
// <embed src="images/SingletonMerge_DiffRootSamePar.svg"
// type="image/svg+xml"/></p>
//
// <p>Different stack tops pointing to different parents. Make array node for
// the root where each element points to the corresponding original
// parent.<br>
// <embed src="images/SingletonMerge_DiffRootDiffPar.svg"
// type="image/svg+xml"/></p>
//
// @param a the first {@link SingletonBasePredictionContext}
// @param b the second {@link SingletonBasePredictionContext}
// @param rootIsWildcard {@code true} if this is a local-context merge,
// otherwise false to indicate a full-context merge
// @param mergeCache
// /
func mergeSingletons(a, b *PredictionContext, rootIsWildcard bool, mergeCache *JPCMap) *PredictionContext {
if mergeCache != nil {
previous, present := mergeCache.Get(a, b)
if present {
return previous
}
previous, present = mergeCache.Get(b, a)
if present {
return previous
}
}
rootMerge := mergeRoot(a, b, rootIsWildcard)
if rootMerge != nil {
if mergeCache != nil {
mergeCache.Put(a, b, rootMerge)
}
return rootMerge
}
if a.returnState == b.returnState {
parent := merge(a.parentCtx, b.parentCtx, rootIsWildcard, mergeCache)
// if parent is same as existing a or b parent or reduced to a parent,
// return it
if parent.Equals(a.parentCtx) {
return a // ax + bx = ax, if a=b
}
if parent.Equals(b.parentCtx) {
return b // ax + bx = bx, if a=b
}
// else: ax + ay = a'[x,y]
// merge parents x and y, giving array node with x,y then remainders
// of those graphs. dup a, a' points at merged array.
// New joined parent so create a new singleton pointing to it, a'
spc := SingletonBasePredictionContextCreate(parent, a.returnState)
if mergeCache != nil {
mergeCache.Put(a, b, spc)
}
return spc
}
// a != b payloads differ
// see if we can collapse parents due to $+x parents if local ctx
var singleParent *PredictionContext
if a.Equals(b) || (a.parentCtx != nil && a.parentCtx.Equals(b.parentCtx)) { // ax +
// bx =
// [a,b]x
singleParent = a.parentCtx
}
if singleParent != nil { // parents are same
// sort payloads and use same parent
payloads := []int{a.returnState, b.returnState}
if a.returnState > b.returnState {
payloads[0] = b.returnState
payloads[1] = a.returnState
}
parents := []*PredictionContext{singleParent, singleParent}
apc := NewArrayPredictionContext(parents, payloads)
if mergeCache != nil {
mergeCache.Put(a, b, apc)
}
return apc
}
// parents differ and can't merge them. Just pack together
// into array can't merge.
// ax + by = [ax,by]
payloads := []int{a.returnState, b.returnState}
parents := []*PredictionContext{a.parentCtx, b.parentCtx}
if a.returnState > b.returnState { // sort by payload
payloads[0] = b.returnState
payloads[1] = a.returnState
parents = []*PredictionContext{b.parentCtx, a.parentCtx}
}
apc := NewArrayPredictionContext(parents, payloads)
if mergeCache != nil {
mergeCache.Put(a, b, apc)
}
return apc
}
// Handle case where at least one of {@code a} or {@code b} is
// {@link //EMPTY}. In the following diagrams, the symbol {@code $} is used
// to represent {@link //EMPTY}.
//
// <h2>Local-Context Merges</h2>
//
// <p>These local-context merge operations are used when {@code rootIsWildcard}
// is true.</p>
//
// <p>{@link //EMPTY} is superset of any graph return {@link //EMPTY}.<br>
// <embed src="images/LocalMerge_EmptyRoot.svg" type="image/svg+xml"/></p>
//
// <p>{@link //EMPTY} and anything is {@code //EMPTY}, so merged parent is
// {@code //EMPTY} return left graph.<br>
// <embed src="images/LocalMerge_EmptyParent.svg" type="image/svg+xml"/></p>
//
// <p>Special case of last merge if local context.<br>
// <embed src="images/LocalMerge_DiffRoots.svg" type="image/svg+xml"/></p>
//
// <h2>Full-Context Merges</h2>
//
// <p>These full-context merge operations are used when {@code rootIsWildcard}
// is false.</p>
//
// <p><embed src="images/FullMerge_EmptyRoots.svg" type="image/svg+xml"/></p>
//
// <p>Must keep all contexts {@link //EMPTY} in array is a special value (and
// nil parent).<br>
// <embed src="images/FullMerge_EmptyRoot.svg" type="image/svg+xml"/></p>
//
// <p><embed src="images/FullMerge_SameRoot.svg" type="image/svg+xml"/></p>
//
// @param a the first {@link SingletonBasePredictionContext}
// @param b the second {@link SingletonBasePredictionContext}
// @param rootIsWildcard {@code true} if this is a local-context merge,
// otherwise false to indicate a full-context merge
// /
func mergeRoot(a, b *PredictionContext, rootIsWildcard bool) *PredictionContext {
if rootIsWildcard {
if a.pcType == PredictionContextEmpty {
return BasePredictionContextEMPTY // // + b =//
}
if b.pcType == PredictionContextEmpty {
return BasePredictionContextEMPTY // a +// =//
}
} else {
if a.isEmpty() && b.isEmpty() {
return BasePredictionContextEMPTY // $ + $ = $
} else if a.isEmpty() { // $ + x = [$,x]
payloads := []int{b.getReturnState(-1), BasePredictionContextEmptyReturnState}
parents := []*PredictionContext{b.GetParent(-1), nil}
return NewArrayPredictionContext(parents, payloads)
} else if b.isEmpty() { // x + $ = [$,x] ($ is always first if present)
payloads := []int{a.getReturnState(-1), BasePredictionContextEmptyReturnState}
parents := []*PredictionContext{a.GetParent(-1), nil}
return NewArrayPredictionContext(parents, payloads)
}
}
return nil
}
// Merge two {@link ArrayBasePredictionContext} instances.
//
// <p>Different tops, different parents.<br>
// <embed src="images/ArrayMerge_DiffTopDiffPar.svg" type="image/svg+xml"/></p>
//
// <p>Shared top, same parents.<br>
// <embed src="images/ArrayMerge_ShareTopSamePar.svg" type="image/svg+xml"/></p>
//
// <p>Shared top, different parents.<br>
// <embed src="images/ArrayMerge_ShareTopDiffPar.svg" type="image/svg+xml"/></p>
//
// <p>Shared top, all shared parents.<br>
// <embed src="images/ArrayMerge_ShareTopSharePar.svg"
// type="image/svg+xml"/></p>
//
// <p>Equal tops, merge parents and reduce top to
// {@link SingletonBasePredictionContext}.<br>
// <embed src="images/ArrayMerge_EqualTop.svg" type="image/svg+xml"/></p>
//
//goland:noinspection GoBoolExpressions
func mergeArrays(a, b *PredictionContext, rootIsWildcard bool, mergeCache *JPCMap) *PredictionContext {
if mergeCache != nil {
previous, present := mergeCache.Get(a, b)
if present {
if runtimeConfig.parserATNSimulatorTraceATNSim {
fmt.Println("mergeArrays a=" + a.String() + ",b=" + b.String() + " -> previous")
}
return previous
}
previous, present = mergeCache.Get(b, a)
if present {
if runtimeConfig.parserATNSimulatorTraceATNSim {
fmt.Println("mergeArrays a=" + a.String() + ",b=" + b.String() + " -> previous")
}
return previous
}
}
// merge sorted payloads a + b => M
i := 0 // walks a
j := 0 // walks b
k := 0 // walks target M array
mergedReturnStates := make([]int, len(a.returnStates)+len(b.returnStates))
mergedParents := make([]*PredictionContext, len(a.returnStates)+len(b.returnStates))
// walk and merge to yield mergedParents, mergedReturnStates
for i < len(a.returnStates) && j < len(b.returnStates) {
aParent := a.parents[i]
bParent := b.parents[j]
if a.returnStates[i] == b.returnStates[j] {
// same payload (stack tops are equal), must yield merged singleton
payload := a.returnStates[i]
// $+$ = $
bothDollars := payload == BasePredictionContextEmptyReturnState && aParent == nil && bParent == nil
axAX := aParent != nil && bParent != nil && aParent.Equals(bParent) // ax+ax
// ->
// ax
if bothDollars || axAX {
mergedParents[k] = aParent // choose left
mergedReturnStates[k] = payload
} else { // ax+ay -> a'[x,y]
mergedParent := merge(aParent, bParent, rootIsWildcard, mergeCache)
mergedParents[k] = mergedParent
mergedReturnStates[k] = payload
}
i++ // hop over left one as usual
j++ // but also Skip one in right side since we merge
} else if a.returnStates[i] < b.returnStates[j] { // copy a[i] to M
mergedParents[k] = aParent
mergedReturnStates[k] = a.returnStates[i]
i++
} else { // b > a, copy b[j] to M
mergedParents[k] = bParent
mergedReturnStates[k] = b.returnStates[j]
j++
}
k++
}
// copy over any payloads remaining in either array
if i < len(a.returnStates) {
for p := i; p < len(a.returnStates); p++ {
mergedParents[k] = a.parents[p]
mergedReturnStates[k] = a.returnStates[p]
k++
}
} else {
for p := j; p < len(b.returnStates); p++ {
mergedParents[k] = b.parents[p]
mergedReturnStates[k] = b.returnStates[p]
k++
}
}
// trim merged if we combined a few that had same stack tops
if k < len(mergedParents) { // write index < last position trim
if k == 1 { // for just one merged element, return singleton top
pc := SingletonBasePredictionContextCreate(mergedParents[0], mergedReturnStates[0])
if mergeCache != nil {
mergeCache.Put(a, b, pc)
}
return pc
}
mergedParents = mergedParents[0:k]
mergedReturnStates = mergedReturnStates[0:k]
}
M := NewArrayPredictionContext(mergedParents, mergedReturnStates)
// if we created same array as a or b, return that instead
// TODO: JI track whether this is possible above during merge sort for speed and possibly avoid an allocation
if M.Equals(a) {
if mergeCache != nil {
mergeCache.Put(a, b, a)
}
if runtimeConfig.parserATNSimulatorTraceATNSim {
fmt.Println("mergeArrays a=" + a.String() + ",b=" + b.String() + " -> a")
}
return a
}
if M.Equals(b) {
if mergeCache != nil {
mergeCache.Put(a, b, b)
}
if runtimeConfig.parserATNSimulatorTraceATNSim {
fmt.Println("mergeArrays a=" + a.String() + ",b=" + b.String() + " -> b")
}
return b
}
combineCommonParents(&mergedParents)
if mergeCache != nil {
mergeCache.Put(a, b, M)
}
if runtimeConfig.parserATNSimulatorTraceATNSim {
fmt.Println("mergeArrays a=" + a.String() + ",b=" + b.String() + " -> " + M.String())
}
return M
}
// Make pass over all M parents and merge any Equals() ones.
// Note that we pass a pointer to the slice as we want to modify it in place.
//
//goland:noinspection GoUnusedFunction
func combineCommonParents(parents *[]*PredictionContext) {
uniqueParents := NewJStore[*PredictionContext, Comparator[*PredictionContext]](pContextEqInst, PredictionContextCollection, "combineCommonParents for PredictionContext")
for p := 0; p < len(*parents); p++ {
parent := (*parents)[p]
_, _ = uniqueParents.Put(parent)
}
for q := 0; q < len(*parents); q++ {
pc, _ := uniqueParents.Get((*parents)[q])
(*parents)[q] = pc
}
}
func getCachedBasePredictionContext(context *PredictionContext, contextCache *PredictionContextCache, visited *VisitRecord) *PredictionContext {
if context.isEmpty() {
return context
}
existing, present := visited.Get(context)
if present {
return existing
}
existing, present = contextCache.Get(context)
if present {
visited.Put(context, existing)
return existing
}
changed := false
parents := make([]*PredictionContext, context.length())
for i := 0; i < len(parents); i++ {
parent := getCachedBasePredictionContext(context.GetParent(i), contextCache, visited)
if changed || !parent.Equals(context.GetParent(i)) {
if !changed {
parents = make([]*PredictionContext, context.length())
for j := 0; j < context.length(); j++ {
parents[j] = context.GetParent(j)
}
changed = true
}
parents[i] = parent
}
}
if !changed {
contextCache.add(context)
visited.Put(context, context)
return context
}
var updated *PredictionContext
if len(parents) == 0 {
updated = BasePredictionContextEMPTY
} else if len(parents) == 1 {
updated = SingletonBasePredictionContextCreate(parents[0], context.getReturnState(0))
} else {
updated = NewArrayPredictionContext(parents, context.GetReturnStates())
}
contextCache.add(updated)
visited.Put(updated, updated)
visited.Put(context, updated)
return updated
}