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|
package dfa
import (
"sort"
spec "urubu/spec/grammar"
)
type symbolTable struct {
symPos2Byte map[symbolPosition]byteRange
endPos2ID map[symbolPosition]spec.LexModeKindID
}
func genSymbolTable(root byteTree) *symbolTable {
symTab := &symbolTable{
symPos2Byte: map[symbolPosition]byteRange{},
endPos2ID: map[symbolPosition]spec.LexModeKindID{},
}
return genSymTab(symTab, root)
}
func genSymTab(symTab *symbolTable, node byteTree) *symbolTable {
if node == nil {
return symTab
}
switch n := node.(type) {
case *symbolNode:
symTab.symPos2Byte[n.pos] = byteRange{
from: n.from,
to: n.to,
}
case *endMarkerNode:
symTab.endPos2ID[n.pos] = n.id
default:
left, right := node.children()
genSymTab(symTab, left)
genSymTab(symTab, right)
}
return symTab
}
type DFA struct {
States []string
InitialState string
AcceptingStatesTable map[string]spec.LexModeKindID
TransitionTable map[string][256]string
}
func GenDFA(root byteTree, symTab *symbolTable) *DFA {
initialState := root.first()
initialStateHash := initialState.hash()
stateMap := map[string]*symbolPositionSet{
initialStateHash: initialState,
}
tranTab := map[string][256]string{}
{
follow := genFollowTable(root)
unmarkedStates := map[string]*symbolPositionSet{
initialStateHash: initialState,
}
for len(unmarkedStates) > 0 {
nextUnmarkedStates := map[string]*symbolPositionSet{}
for hash, state := range unmarkedStates {
tranTabOfState := [256]*symbolPositionSet{}
for _, pos := range state.set() {
if pos.isEndMark() {
continue
}
valRange := symTab.symPos2Byte[pos]
for symVal := valRange.from; symVal <= valRange.to; symVal++ {
if tranTabOfState[symVal] == nil {
tranTabOfState[symVal] = newSymbolPositionSet()
}
tranTabOfState[symVal].merge(follow[pos])
}
}
for _, t := range tranTabOfState {
if t == nil {
continue
}
h := t.hash()
if _, ok := stateMap[h]; ok {
continue
}
stateMap[h] = t
nextUnmarkedStates[h] = t
}
tabOfState := [256]string{}
for v, t := range tranTabOfState {
if t == nil {
continue
}
tabOfState[v] = t.hash()
}
tranTab[hash] = tabOfState
}
unmarkedStates = nextUnmarkedStates
}
}
accTab := map[string]spec.LexModeKindID{}
{
for h, s := range stateMap {
for _, pos := range s.set() {
if !pos.isEndMark() {
continue
}
priorID, ok := accTab[h]
if !ok {
accTab[h] = symTab.endPos2ID[pos]
} else {
id := symTab.endPos2ID[pos]
if id < priorID {
accTab[h] = id
}
}
}
}
}
var states []string
{
for s := range stateMap {
states = append(states, s)
}
sort.Slice(states, func(i, j int) bool {
return states[i] < states[j]
})
}
return &DFA{
States: states,
InitialState: initialStateHash,
AcceptingStatesTable: accTab,
TransitionTable: tranTab,
}
}
func GenTransitionTable(dfa *DFA) (*spec.TransitionTable, error) {
stateHash2ID := map[string]spec.StateID{}
for i, s := range dfa.States {
// Since 0 represents an invalid value in a transition table,
// assign a number greater than or equal to 1 to states.
stateHash2ID[s] = spec.StateID(i + spec.StateIDMin.Int())
}
acc := make([]spec.LexModeKindID, len(dfa.States)+1)
for _, s := range dfa.States {
id, ok := dfa.AcceptingStatesTable[s]
if !ok {
continue
}
acc[stateHash2ID[s]] = id
}
rowCount := len(dfa.States) + 1
colCount := 256
tran := make([]spec.StateID, rowCount*colCount)
for s, tab := range dfa.TransitionTable {
for v, to := range tab {
tran[stateHash2ID[s].Int()*256+v] = stateHash2ID[to]
}
}
return &spec.TransitionTable{
InitialStateID: stateHash2ID[dfa.InitialState],
AcceptingStates: acc,
UncompressedTransition: tran,
RowCount: rowCount,
ColCount: colCount,
}, nil
}
|
