Esempio n. 1
0
func seekElse(s *scanner.Scanner) error {
	ifDepth := 0
loop:
	for {

		tok := s.Scan()
		switch tok {
		case token.ENDOFSCRIPT:
			return errors.New("Unclosed IF Statements")
		case token.IF:
			ifDepth++
		case token.ENDIF:
			if ifDepth == 0 {
				break loop
			} else {
				ifDepth--
			}
		case token.ELSE:
			if ifDepth == 0 {
				break loop
			}
		}
	}

	return nil
}
Esempio n. 2
0
func Subscriptify(script []byte, sig []byte) ([]byte, error) {

	s := new(scanner.Scanner)
	s.Init(script, nil)

	subscript := make([]byte, 0, len(script))

loop:
	for {
		tok := s.Scan()
		switch tok {
		case token.DATA:
			//Suppress the signature
			if !bytes.Equal(s.Data(), sig) {
				subscript = append(subscript, s.ByteCode())
				subscript = append(subscript, s.Data()...)
			}
		case token.CODESEPARATOR:
			//Remove code separators
		case token.ENDOFSCRIPT:
			break loop
		case token.INVALID:
			return nil, errors.New("Invalid Token")
		default:
			//All other tokens are passed straight through
			subscript = append(subscript, s.ByteCode())
		}
	}

	if s.ErrorCount() != 0 {
		return nil, errors.New("Scanner Errors Occured")
	}

	return subscript, nil
}
Esempio n. 3
0
func (this *Executor) execScanner(script []byte) error {
	s := new(scanner.Scanner)
	s.Init(script, nil)

	ifDepth := 0

loop:
	for {
		tok := s.Scan()
		switch tok {
		case token.DATA:
			this.Push(s.Data())
		case token.OPERATION:
			impl := opCodeImpls[s.Op()]
			if impl == nil {
				return errors.New("Unknown OpCode - " + s.Op().String())
			}

			err := impl(&this.Context)
			if err != nil {
				return err
			}
		case token.ENDOFSCRIPT:
			break loop
		case token.NUMBER:
			this.PushNumber(s.Number())

		case token.CODESEPARATOR:
			this.codeSeparatorPos = s.Pos()
		case token.IF:
			ifDepth++
			top := this.PopBool()
			if !top {
				seekElse(s)
			}
		case token.NOTIF:
			ifDepth++
			top := this.PopBool()
			if top {
				seekElse(s)
			}
		case token.ELSE:
			if ifDepth == 0 {
				return errors.New("Unexpected EndIf")
			}
			ifDepth--
			seekEndIf(s)
		case token.ENDIF:
			if ifDepth == 0 {
				return errors.New("Unexpected Else")
			}
			ifDepth--
		case token.INVALID:
			return errors.New("Invalid Token")

		}
	}

	if ifDepth != 0 {
		return errors.New("Unclosed If")
	}

	if s.ErrorCount() != 0 {
		return errors.New("TokenSource reported errors")
	}

	return nil
}