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// Copyright (c) 2012-2017 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"
type ATNConfigSet interface {
hash() int
Add(ATNConfig, *DoubleDict) bool
AddAll([]ATNConfig) bool
GetStates() *Set
GetPredicates() []SemanticContext
GetItems() []ATNConfig
OptimizeConfigs(interpreter *BaseATNSimulator)
Equals(other interface{}) bool
Length() int
IsEmpty() bool
Contains(ATNConfig) bool
ContainsFast(ATNConfig) bool
Clear()
String() string
HasSemanticContext() bool
SetHasSemanticContext(v bool)
ReadOnly() bool
SetReadOnly(bool)
GetConflictingAlts() *BitSet
SetConflictingAlts(*BitSet)
FullContext() bool
GetUniqueAlt() int
SetUniqueAlt(int)
GetDipsIntoOuterContext() bool
SetDipsIntoOuterContext(bool)
}
// BaseATNConfigSet is a specialized set of ATNConfig that tracks information
// about its elements and can combine similar configurations using a
// graph-structured stack.
type BaseATNConfigSet struct {
cachedHash int
// configLookup is used to determine whether two BaseATNConfigSets are equal. We
// need all configurations with the same (s, i, _, semctx) to be equal. A key
// effectively doubles the number of objects associated with ATNConfigs. All
// keys are hashed by (s, i, _, pi), not including the context. Wiped out when
// read-only because a set becomes a DFA state.
configLookup *Set
// configs is the added elements.
configs []ATNConfig
// TODO: These fields make me pretty uncomfortable, but it is nice to pack up
// info together because it saves recomputation. Can we track conflicts as they
// are added to save scanning configs later?
conflictingAlts *BitSet
// dipsIntoOuterContext is used by parsers and lexers. In a lexer, it indicates
// we hit a pred while computing a closure operation. Do not make a DFA state
// from the BaseATNConfigSet in this case. TODO: How is this used by parsers?
dipsIntoOuterContext bool
// fullCtx is whether it is part of a full context LL prediction. Used to
// determine how to merge $. It is a wildcard with SLL, but not for an LL
// context merge.
fullCtx bool
// Used in parser and lexer. In lexer, it indicates we hit a pred
// while computing a closure operation. Don't make a DFA state from a.
hasSemanticContext bool
// readOnly is whether it is read-only. Do not
// allow any code to manipulate the set if true because DFA states will point at
// sets and those must not change. It not protect other fields; conflictingAlts
// in particular, which is assigned after readOnly.
readOnly bool
// TODO: These fields make me pretty uncomfortable, but it is nice to pack up
// info together because it saves recomputation. Can we track conflicts as they
// are added to save scanning configs later?
uniqueAlt int
}
func NewBaseATNConfigSet(fullCtx bool) *BaseATNConfigSet {
return &BaseATNConfigSet{
cachedHash: -1,
configLookup: NewSet(nil, equalATNConfigs),
fullCtx: fullCtx,
}
}
// Add merges contexts with existing configs for (s, i, pi, _), where s is the
// ATNConfig.state, i is the ATNConfig.alt, and pi is the
// ATNConfig.semanticContext. We use (s,i,pi) as the key. Updates
// dipsIntoOuterContext and hasSemanticContext when necessary.
func (b *BaseATNConfigSet) Add(config ATNConfig, mergeCache *DoubleDict) bool {
if b.readOnly {
panic("set is read-only")
}
if config.GetSemanticContext() != SemanticContextNone {
b.hasSemanticContext = true
}
if config.GetReachesIntoOuterContext() > 0 {
b.dipsIntoOuterContext = true
}
existing := b.configLookup.add(config).(ATNConfig)
if existing == config {
b.cachedHash = -1
b.configs = append(b.configs, config) // Track order here
return true
}
// Merge a previous (s, i, pi, _) with it and save the result
rootIsWildcard := !b.fullCtx
merged := merge(existing.GetContext(), config.GetContext(), rootIsWildcard, mergeCache)
// No need to check for existing.context because config.context is in the cache,
// since the only way to create new graphs is the "call rule" and here. We cache
// at both places.
existing.SetReachesIntoOuterContext(intMax(existing.GetReachesIntoOuterContext(), config.GetReachesIntoOuterContext()))
// Preserve the precedence filter suppression during the merge
if config.getPrecedenceFilterSuppressed() {
existing.setPrecedenceFilterSuppressed(true)
}
// Replace the context because there is no need to do alt mapping
existing.SetContext(merged)
return true
}
func (b *BaseATNConfigSet) GetStates() *Set {
states := NewSet(nil, nil)
for i := 0; i < len(b.configs); i++ {
states.add(b.configs[i].GetState())
}
return states
}
func (b *BaseATNConfigSet) HasSemanticContext() bool {
return b.hasSemanticContext
}
func (b *BaseATNConfigSet) SetHasSemanticContext(v bool) {
b.hasSemanticContext = v
}
func (b *BaseATNConfigSet) GetPredicates() []SemanticContext {
preds := make([]SemanticContext, 0)
for i := 0; i < len(b.configs); i++ {
c := b.configs[i].GetSemanticContext()
if c != SemanticContextNone {
preds = append(preds, c)
}
}
return preds
}
func (b *BaseATNConfigSet) GetItems() []ATNConfig {
return b.configs
}
func (b *BaseATNConfigSet) OptimizeConfigs(interpreter *BaseATNSimulator) {
if b.readOnly {
panic("set is read-only")
}
if b.configLookup.length() == 0 {
return
}
for i := 0; i < len(b.configs); i++ {
config := b.configs[i]
config.SetContext(interpreter.getCachedContext(config.GetContext()))
}
}
func (b *BaseATNConfigSet) AddAll(coll []ATNConfig) bool {
for i := 0; i < len(coll); i++ {
b.Add(coll[i], nil)
}
return false
}
func (b *BaseATNConfigSet) Equals(other interface{}) bool {
if b == other {
return true
} else if _, ok := other.(*BaseATNConfigSet); !ok {
return false
}
other2 := other.(*BaseATNConfigSet)
return b.configs != nil &&
// TODO: b.configs.equals(other2.configs) && // TODO: Is b necessary?
b.fullCtx == other2.fullCtx &&
b.uniqueAlt == other2.uniqueAlt &&
b.conflictingAlts == other2.conflictingAlts &&
b.hasSemanticContext == other2.hasSemanticContext &&
b.dipsIntoOuterContext == other2.dipsIntoOuterContext
}
func (b *BaseATNConfigSet) hash() int {
if b.readOnly {
if b.cachedHash == -1 {
b.cachedHash = b.hashCodeConfigs()
}
return b.cachedHash
}
return b.hashCodeConfigs()
}
func (b *BaseATNConfigSet) hashCodeConfigs() int {
h := murmurInit(1)
for _, c := range b.configs {
if c != nil {
h = murmurUpdate(h, c.hash())
}
}
return murmurFinish(h, len(b.configs))
}
func (b *BaseATNConfigSet) Length() int {
return len(b.configs)
}
func (b *BaseATNConfigSet) IsEmpty() bool {
return len(b.configs) == 0
}
func (b *BaseATNConfigSet) Contains(item ATNConfig) bool {
if b.configLookup == nil {
panic("not implemented for read-only sets")
}
return b.configLookup.contains(item)
}
func (b *BaseATNConfigSet) ContainsFast(item ATNConfig) bool {
if b.configLookup == nil {
panic("not implemented for read-only sets")
}
return b.configLookup.contains(item) // TODO: containsFast is not implemented for Set
}
func (b *BaseATNConfigSet) Clear() {
if b.readOnly {
panic("set is read-only")
}
b.configs = make([]ATNConfig, 0)
b.cachedHash = -1
b.configLookup = NewSet(nil, equalATNConfigs)
}
func (b *BaseATNConfigSet) FullContext() bool {
return b.fullCtx
}
func (b *BaseATNConfigSet) GetDipsIntoOuterContext() bool {
return b.dipsIntoOuterContext
}
func (b *BaseATNConfigSet) SetDipsIntoOuterContext(v bool) {
b.dipsIntoOuterContext = v
}
func (b *BaseATNConfigSet) GetUniqueAlt() int {
return b.uniqueAlt
}
func (b *BaseATNConfigSet) SetUniqueAlt(v int) {
b.uniqueAlt = v
}
func (b *BaseATNConfigSet) GetConflictingAlts() *BitSet {
return b.conflictingAlts
}
func (b *BaseATNConfigSet) SetConflictingAlts(v *BitSet) {
b.conflictingAlts = v
}
func (b *BaseATNConfigSet) ReadOnly() bool {
return b.readOnly
}
func (b *BaseATNConfigSet) SetReadOnly(readOnly bool) {
b.readOnly = readOnly
if readOnly {
b.configLookup = nil // Read only, so no need for the lookup cache
}
}
func (b *BaseATNConfigSet) String() string {
s := "["
for i, c := range b.configs {
s += c.String()
if i != len(b.configs)-1 {
s += ", "
}
}
s += "]"
if b.hasSemanticContext {
s += ",hasSemanticContext=" + fmt.Sprint(b.hasSemanticContext)
}
if b.uniqueAlt != ATNInvalidAltNumber {
s += ",uniqueAlt=" + fmt.Sprint(b.uniqueAlt)
}
if b.conflictingAlts != nil {
s += ",conflictingAlts=" + b.conflictingAlts.String()
}
if b.dipsIntoOuterContext {
s += ",dipsIntoOuterContext"
}
return s
}
type OrderedATNConfigSet struct {
*BaseATNConfigSet
}
func NewOrderedATNConfigSet() *OrderedATNConfigSet {
b := NewBaseATNConfigSet(false)
b.configLookup = NewSet(nil, nil)
return &OrderedATNConfigSet{BaseATNConfigSet: b}
}
func equalATNConfigs(a, b interface{}) bool {
if a == nil || b == nil {
return false
}
if a == b {
return true
}
var ai, ok = a.(ATNConfig)
var bi, ok1 = b.(ATNConfig)
if !ok || !ok1 {
return false
}
nums := ai.GetState().GetStateNumber() == bi.GetState().GetStateNumber()
alts := ai.GetAlt() == bi.GetAlt()
cons := ai.GetSemanticContext().equals(bi.GetSemanticContext())
return nums && alts && cons
}
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