func Thompson(program InstSlice, text []byte) bool {
var cqueue, nqueue *queue.Queue = queue.New(), queue.New()
cqueue.Push(0)
for tc := 0; tc <= len(text); tc++ {
for !cqueue.Empty() {
pc := cqueue.Pop()
inst := program[pc]
switch inst.Op {
case CHAR:
if int(tc) < len(text) && text[tc] == byte(inst.X) {
nqueue.Push(pc + 1)
}
case MATCH:
if tc == len(text) {
return true
}
case JMP:
cqueue.Push(inst.X)
case SPLIT:
cqueue.Push(inst.X)
cqueue.Push(inst.Y)
}
}
cqueue, nqueue = nqueue, cqueue
}
return false
}
func LexerEngine(program InstSlice, text []byte) (chan bool, chan Match) {
matches := make(chan Match)
success := make(chan bool)
go func() {
var cqueue, nqueue *queue.Queue = queue.New(), queue.New()
match_pc := -1
match_tc := -1
start_tc := 0
cqueue.Push(0)
for tc := 0; tc <= len(text); tc++ {
for !cqueue.Empty() {
pc := cqueue.Pop()
inst := program[pc]
switch inst.Op {
case CHAR:
if int(tc) < len(text) && text[tc] == byte(inst.X) {
nqueue.Push(pc + 1)
}
case MATCH:
if match_tc < tc {
match_pc = int(pc)
match_tc = tc
} else if match_pc > int(pc) {
match_pc = int(pc)
match_tc = tc
}
case JMP:
cqueue.Push(inst.X)
case SPLIT:
cqueue.Push(inst.X)
cqueue.Push(inst.Y)
}
}
cqueue, nqueue = nqueue, cqueue
if cqueue.Empty() && match_pc != -1 {
matches <- Match{text[start_tc:match_tc], match_pc}
cqueue.Push(0)
start_tc = tc
match_pc = -1
tc -= 1
}
}
close(matches)
if match_tc == len(text) {
success <- true
} else {
success <- false
}
close(success)
}()
return success, matches
}