docs: public final void mOCTAL_ESC() throws RecognitionException {
          try {
              // com/dyuproject/protostuff/parser/ProtoLexer.g:287:5: ( '\\\\' ( '0' .. '3' ) ( '0' .. '7' ) ( '0' .. '7' ) | '\\\\' ( '0' .. '7' ) ( '0' .. '7' ) | '\\\\' ( '0' .. '7' ) )
              int alt19=3;
              switch ( input.LA(1) ) {
              case '\\':
                  {
                  switch ( input.LA(2) ) {
                  case '0':
                  case '1':
                  case '2':
                  case '3':
                      {
                      switch ( input.LA(3) ) {
                      case '0':
                      case '1':
                      case '2':
                      case '3':
                      case '4':
                      case '5':
                      case '6':
                      case '7':
                          {
                          switch ( input.LA(4) ) {
                          case '0':
                          case '1':
                          case '2':
                          case '3':
                          case '4':
                          case '5':
                          case '6':
                          case '7':
                              {
                              alt19=1;
                              }
                              break;
                          default:
                              alt19=2;}
  
                          }
                          break;
                      default:
                          alt19=3;}
  
                      }
                      break;
                  case '4':
                  case '5':
                  case '6':
                  case '7':
                      {
                      switch ( input.LA(3) ) {
                      case '0':
                      case '1':
                      case '2':
                      case '3':
                      case '4':
                      case '5':
                      case '6':
                      case '7':
                          {
                          alt19=2;
                          }
                          break;
                      default:
                          alt19=3;}
  
                      }
                      break;
                  default:
                      NoViableAltException nvae =
                          new NoViableAltException("", 19, 1, input);
  
                      throw nvae;
                  }
  
                  }
                  break;
              default:
                  NoViableAltException nvae =
                      new NoViableAltException("", 19, 0, input);
  
                  throw nvae;
              }
  
              switch (alt19) {
                  case 1 :
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:287:9: '\\\\' ( '0' .. '3' ) ( '0' .. '7' ) ( '0' .. '7' )
                      {
                      match('\\'); 
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:287:14: ( '0' .. '3' )
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:287:15: '0' .. '3'
                      {
                      matchRange('0','3'); 
  
                      }
  
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:287:25: ( '0' .. '7' )
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:287:26: '0' .. '7'
                      {
                      matchRange('0','7'); 
  
                      }
  
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:287:36: ( '0' .. '7' )
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:287:37: '0' .. '7'
                      {
                      matchRange('0','7'); 
  
                      }
  
  
                      }
                      break;
                  case 2 :
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:288:9: '\\\\' ( '0' .. '7' ) ( '0' .. '7' )
                      {
                      match('\\'); 
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:288:14: ( '0' .. '7' )
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:288:15: '0' .. '7'
                      {
                      matchRange('0','7'); 
  
                      }
  
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:288:25: ( '0' .. '7' )
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:288:26: '0' .. '7'
                      {
                      matchRange('0','7'); 
  
                      }
  
  
                      }
                      break;
                  case 3 :
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:289:9: '\\\\' ( '0' .. '7' )
                      {
                      match('\\'); 
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:289:14: ( '0' .. '7' )
                      // com/dyuproject/protostuff/parser/ProtoLexer.g:289:15: '0' .. '7'
                      {
                      matchRange('0','7'); 
  
                      }
  
  
                      }
                      break;
  
              }
          }
          finally {
          }
      }