// check if the fastresume data is up to date
	// if it is, use it and return true. If it 
	// isn't return false and the full check
	// will be run
	int piece_manager::check_fastresume(
		lazy_entry const& rd, error_code& error)
	{
		mutex::scoped_lock lock(m_mutex);

		INVARIANT_CHECK;

		TORRENT_ASSERT(m_files.piece_length() > 0);
		
		m_current_slot = 0;

		// if we don't have any resume data, return
		if (rd.type() == lazy_entry::none_t) return check_no_fastresume(error);

		if (rd.type() != lazy_entry::dict_t)
		{
			error = errors::not_a_dictionary;
			return check_no_fastresume(error);
		}

		int block_size = (std::min)(16 * 1024, m_files.piece_length());
		int blocks_per_piece = int(rd.dict_find_int_value("blocks per piece", -1));
		if (blocks_per_piece != -1
			&& blocks_per_piece != m_files.piece_length() / block_size)
		{
			error = errors::invalid_blocks_per_piece;
			return check_no_fastresume(error);
		}

		if (!m_storage->verify_resume_data(rd, error))
			return check_no_fastresume(error);

		return check_init_storage(error);
	}

	bool uTorrentParser::parse_torrent_file(lazy_entry const& torrent_file, error_code& ec)
	{
		if (torrent_file.type() != lazy_entry::dict_t)
		{
			ec = errors::torrent_is_no_dict;
			return false;
		}

		mTorrents.clear();
		
		
		for (int i = 0, end(torrent_file.dict_size()); i < end; ++i)
		{
			std::pair<std::string, lazy_entry const*> n = torrent_file.dict_at(i);
			if (lazy_entry::dict_t == n.second->type())
			{
				std::pair<std::string, std::string> torrent;
				torrent.first = n.first;
				torrent.second = n.second->dict_find_string_value("path");
				std::string caption = n.second->dict_find_string_value("caption");
				if (caption.length() > 0) {
					size_t pos = torrent.second.find(caption.c_str(), 0, caption.length());
					torrent.second = torrent.second.substr(0, pos);
				}
				mTorrents.push_back(torrent);
			}			
		}

		return true;
	}

void feed::load_state(lazy_entry const& rd)
{
	load_struct(rd, this, feed_map, sizeof(feed_map)/sizeof(feed_map[0]));
	lazy_entry const* e = rd.dict_find_list("items");
	if (e)
	{
		m_items.reserve(e->list_size());
		for (int i = 0; i < e->list_size(); ++i)
		{
			if (e->list_at(i)->type() != lazy_entry::dict_t) continue;
			m_items.push_back(feed_item());
			load_struct(*e->list_at(i), &m_items.back(), feed_item_map
				, sizeof(feed_item_map)/sizeof(feed_item_map[0]));

			// don't load duplicates
			if (m_urls.find(m_items.back().url) != m_urls.end())
			{
				m_items.pop_back();
				continue;
			}
			m_urls.insert(m_items.back().url);
		}
	}
	load_struct(rd, &m_settings, feed_settings_map
		, sizeof(feed_settings_map)/sizeof(feed_settings_map[0]));
	e = rd.dict_find_dict("add_params");
	if (e)
	{
		load_struct(*e, &m_settings.add_args, add_torrent_map
			, sizeof(add_torrent_map)/sizeof(add_torrent_map[0]));
	}

	e = rd.dict_find_list("history");
	if (e)
	{
		for (int i = 0; i < e->list_size(); ++i)
		{
			if (e->list_at(i)->type() != lazy_entry::list_t) continue;

			lazy_entry const* item = e->list_at(i);

			if (item->list_size() != 2
				|| item->list_at(0)->type() != lazy_entry::string_t
				|| item->list_at(1)->type() != lazy_entry::int_t)
				continue;

			m_added.insert(std::pair<std::string, time_t>(
				item->list_at(0)->string_value()
				, item->list_at(1)->int_value()));
		}
	}
}

// convert a lazy_entry into an old skool entry
void entry::operator=(lazy_entry const& e)
{
    switch (e.type())
    {
    case lazy_entry::string_t:
        this->string() = e.string_value();
        break;
    case lazy_entry::int_t:
        this->integer() = e.int_value();
        break;
    case lazy_entry::dict_t:
    {
        dictionary_type& d = this->dict();
        for (int i = 0; i < e.dict_size(); ++i)
        {
            std::pair<std::string, lazy_entry const*> elem = e.dict_at(i);
            d[elem.first] = *elem.second;
        }
        break;
    }
    case lazy_entry::list_t:
    {
        list_type& l = this->list();
        for (int i = 0; i < e.list_size(); ++i)
        {
            l.push_back(entry());
            l.back() = *e.list_at(i);
        }
        break;
    }
    case lazy_entry::none_t:
        destruct();
        break;
    }
}

	void session_handle::load_state(lazy_entry const& ses_state
		, std::uint32_t const flags)
	{
		if (ses_state.type() == lazy_entry::none_t) return;
		std::pair<char const*, int> buf = ses_state.data_section();
		bdecode_node e;
		error_code ec;
#if TORRENT_USE_ASSERTS || !defined BOOST_NO_EXCEPTIONS
		int ret =
#endif
		bdecode(buf.first, buf.first + buf.second, e, ec);

		TORRENT_ASSERT(ret == 0);
#ifndef BOOST_NO_EXCEPTIONS
		if (ret != 0) throw system_error(ec);
#endif
		sync_call(&session_impl::load_state, &e, flags);
	}

	int line_longer_than(lazy_entry const& e, int limit)
	{
		int line_len = 0;
		switch (e.type())
		{
		case lazy_entry::list_t:
			line_len += 4;
			if (line_len > limit) return -1;
			for (int i = 0; i < e.list_size(); ++i)
			{
				int ret = line_longer_than(*e.list_at(i), limit - line_len);
				if (ret == -1) return -1;
				line_len += ret + 2;
			}
			break;
		case lazy_entry::dict_t:
			line_len += 4;
			if (line_len > limit) return -1;
			for (int i = 0; i < e.dict_size(); ++i)
			{
				line_len += 4 + e.dict_at(i).first.size();
				if (line_len > limit) return -1;
				int ret = line_longer_than(*e.dict_at(i).second, limit - line_len);
				if (ret == -1) return -1;
				line_len += ret + 1;
			}
			break;
		case lazy_entry::string_t:
			line_len += 3 + e.string_length();
			break;
		case lazy_entry::int_t:
		{
			size_type val = e.int_value();
			while (val > 0)
			{
				++line_len;
				val /= 10;
			}
			line_len += 2;
		}
		break;
		case lazy_entry::none_t:
			line_len += 4;
			break;
		}
	
		if (line_len > limit) return -1;
		return line_len;
	}

	bool http_tracker_connection::extract_peer_info(lazy_entry const& info, peer_entry& ret)
	{
		// extract peer id (if any)
		if (info.type() != lazy_entry::dict_t)
		{
			fail(error_code(errors::invalid_peer_dict));
			return false;
		}
		lazy_entry const* i = info.dict_find_string("peer id");
		if (i != 0 && i->string_length() == 20)
		{
			std::copy(i->string_ptr(), i->string_ptr()+20, ret.pid.begin());
		}
		else
		{
			// if there's no peer_id, just initialize it to a bunch of zeroes
			std::fill_n(ret.pid.begin(), 20, 0);
		}

		// extract ip
		i = info.dict_find_string("ip");
		if (i == 0)
		{
			fail(error_code(errors::invalid_tracker_response));
			return false;
		}
		ret.ip = i->string_value();

		// extract port
		i = info.dict_find_int("port");
		if (i == 0)
		{
			fail(error_code(errors::invalid_tracker_response));
			return false;
		}
		ret.port = (unsigned short)i->int_value();

		return true;
	}

	bool default_storage::verify_resume_data(lazy_entry const& rd, error_code& error)
	{
		lazy_entry const* file_priority = rd.dict_find_list("file_priority");
		if (file_priority && file_priority->list_size()
			== files().num_files())
		{
			m_file_priority.resize(file_priority->list_size());
			for (int i = 0; i < file_priority->list_size(); ++i)
				m_file_priority[i] = boost::uint8_t(file_priority->list_int_value_at(i, 1));
		}


		bool seed = false;
		
        if (lazy_entry const* pieces = rd.dict_find_string("pieces"))
		{
			if (int(pieces->string_length()) == m_files.num_pieces())
			{
				seed = true;
				char const* p = pieces->string_ptr();
				for (int i = 0; i < pieces->string_length(); ++i)
				{
					if ((p[i] & 1) == 1) continue;
					seed = false;
					break;
				}
			}
		}
		else
		{
			error = errors::missing_pieces;
			return false;
		}

        int flags = (settings().ignore_resume_timestamps ? ignore_timestamps : 0);

        return true;

	}

std::string parse_dht_client(lazy_entry const& e)
{
    lazy_entry const* ver = e.dict_find_string("v");
    if (!ver) return "generic";
    std::string const& client = ver->string_value();
    if (client.size() < 2)
    {
        ++g_unknown_message_input;
        return client;
    }
    else if (std::equal(client.begin(), client.begin() + 2, "Az"))
    {
        ++g_az_message_input;
        return "Azureus";
    }
    else if (std::equal(client.begin(), client.begin() + 2, "UT"))
    {
        ++g_ut_message_input;
        return "uTorrent";
    }
    else if (std::equal(client.begin(), client.begin() + 2, "LT"))
    {
        ++g_lt_message_input;
        return "libtorrent";
    }
    else if (std::equal(client.begin(), client.begin() + 2, "MP"))
    {
        ++g_mp_message_input;
        return "MooPolice";
    }
    else if (std::equal(client.begin(), client.begin() + 2, "GR"))
    {
        ++g_gr_message_input;
        return "GetRight";
    }
    else if (std::equal(client.begin(), client.begin() + 2, "MO"))
    {
        ++g_mo_message_input;
        return "Mono Torrent";
    }
    else
    {
        ++g_unknown_message_input;
        return client;
    }
}

	void load_struct(lazy_entry const& e, void* s, bencode_map_entry const* m, int num)
	{
		for (int i = 0; i < num; ++i)
		{
			lazy_entry const* key = e.dict_find(m[i].name);
			if (key == 0) continue;
			void* dest = ((char*)s) + m[i].offset;
			switch (m[i].type)
			{
				case std_string:
				{
					if (key->type() != lazy_entry::string_t) continue;
					*((std::string*)dest) = key->string_value();
					break;
				}
				case character:
				case boolean:
				case integer:
				case size_integer:
				case time_integer:
				case floating_point:
				{
					if (key->type() != lazy_entry::int_t) continue;
					size_type val = key->int_value();
					switch (m[i].type)
					{
						case character: *((char*)dest) = char(val); break;
						case integer: *((int*)dest) = int(val); break;
						case size_integer: *((size_type*)dest) = size_type(val); break;
						case time_integer: *((time_t*)dest) = time_t(val); break;
						case floating_point: *((float*)dest) = float(val) / 1000.f; break;
						case boolean: *((bool*)dest) = (val != 0); break;
					}
				}
			}
		}
	}

	void http_tracker_connection::parse(int status_code, lazy_entry const& e)
	{
		boost::shared_ptr<request_callback> cb = requester();
		if (!cb) return;

		int interval = int(e.dict_find_int_value("interval", 1800));
		int min_interval = int(e.dict_find_int_value("min interval", 60));

		std::string trackerid;
		lazy_entry const* tracker_id = e.dict_find_string("tracker id");
		if (tracker_id)
			trackerid = tracker_id->string_value();
		// parse the response
		lazy_entry const* failure = e.dict_find_string("failure reason");
		if (failure)
		{
			fail(error_code(errors::tracker_failure), status_code
				, failure->string_value().c_str(), interval, min_interval);
			return;
		}

		lazy_entry const* warning = e.dict_find_string("warning message");
		if (warning)
			cb->tracker_warning(tracker_req(), warning->string_value());

		std::vector<peer_entry> peer_list;

		if (tracker_req().kind == tracker_request::scrape_request)
		{
			std::string ih = tracker_req().info_hash.to_string();

			lazy_entry const* files = e.dict_find_dict("files");
			if (files == 0)
			{
				fail(error_code(errors::invalid_files_entry), -1, ""
					, interval, min_interval);
				return;
			}

			lazy_entry const* scrape_data = files->dict_find_dict(ih.c_str());
			if (scrape_data == 0)
			{
				fail(error_code(errors::invalid_hash_entry), -1, ""
					, interval, min_interval);
				return;
			}
			int complete = int(scrape_data->dict_find_int_value("complete", -1));
			int incomplete = int(scrape_data->dict_find_int_value("incomplete", -1));
			int downloaded = int(scrape_data->dict_find_int_value("downloaded", -1));
			int downloaders = int(scrape_data->dict_find_int_value("downloaders", -1));
			cb->tracker_scrape_response(tracker_req(), complete
				, incomplete, downloaded, downloaders);
			return;
		}

		lazy_entry const* peers_ent = e.dict_find("peers");
		if (peers_ent && peers_ent->type() == lazy_entry::string_t)
		{
			char const* peers = peers_ent->string_ptr();
			int len = peers_ent->string_length();
			for (int i = 0; i < len; i += 6)
			{
				if (len - i < 6) break;

				peer_entry p;
				p.pid.clear();
				error_code ec;
				p.ip = detail::read_v4_address(peers).to_string(ec);
				p.port = detail::read_uint16(peers);
				if (ec) continue;
				peer_list.push_back(p);
			}
		}
		else if (peers_ent && peers_ent->type() == lazy_entry::list_t)
		{
			int len = peers_ent->list_size();
			for (int i = 0; i < len; ++i)
			{
				peer_entry p;
				if (!extract_peer_info(*peers_ent->list_at(i), p)) return;
				peer_list.push_back(p);
			}
		}
		else
		{
			peers_ent = 0;
		}

#if TORRENT_USE_IPV6
		lazy_entry const* ipv6_peers = e.dict_find_string("peers6");
		if (ipv6_peers)
		{
			char const* peers = ipv6_peers->string_ptr();
			int len = ipv6_peers->string_length();
			for (int i = 0; i < len; i += 18)
			{
				if (len - i < 18) break;

				peer_entry p;
				p.pid.clear();
//.........这里部分代码省略.........

	// return 0 = success
	int lazy_bdecode(char const* start, char const* end, lazy_entry& ret
		, error_code& ec, int* error_pos, int depth_limit, int item_limit)
	{
		char const* const orig_start = start;
		ret.clear();
		if (start == end) return 0;

		std::vector<lazy_entry*> stack;

		stack.push_back(&ret);
		while (start < end)
		{
			if (stack.empty()) break; // done!

			lazy_entry* top = stack.back();

			if (int(stack.size()) > depth_limit) TORRENT_FAIL_BDECODE(errors::depth_exceeded);
			if (start >= end) TORRENT_FAIL_BDECODE(errors::unexpected_eof);
			char t = *start;
			++start;
			if (start >= end && t != 'e') TORRENT_FAIL_BDECODE(errors::unexpected_eof);

			switch (top->type())
			{
				case lazy_entry::dict_t:
				{
					if (t == 'e')
					{
						top->set_end(start);
						stack.pop_back();
						continue;
					}
					if (!is_digit(t)) TORRENT_FAIL_BDECODE(errors::expected_string);
					boost::int64_t len = t - '0';
					start = parse_int(start, end, ':', len);
					if (start == 0 || start + len + 3 > end || *start != ':')
						TORRENT_FAIL_BDECODE(errors::expected_colon);
					++start;
					if (start == end) TORRENT_FAIL_BDECODE(errors::unexpected_eof);
					lazy_entry* ent = top->dict_append(start);
					if (ent == 0) TORRENT_FAIL_BDECODE(errors::no_memory);
					start += len;
					if (start >= end) TORRENT_FAIL_BDECODE(errors::unexpected_eof);
					stack.push_back(ent);
					t = *start;
					++start;
					break;
				}
				case lazy_entry::list_t:
				{
					if (t == 'e')
					{
						top->set_end(start);
						stack.pop_back();
						continue;
					}
					lazy_entry* ent = top->list_append();
					if (ent == 0) TORRENT_FAIL_BDECODE(errors::no_memory);
					stack.push_back(ent);
					break;
				}
				default: break;
			}

			--item_limit;
			if (item_limit <= 0) TORRENT_FAIL_BDECODE(errors::limit_exceeded);

			top = stack.back();
			switch (t)
			{
				case 'd':
					top->construct_dict(start - 1);
					continue;
				case 'l':
					top->construct_list(start - 1);
					continue;
				case 'i':
				{
					char const* int_start = start;
					start = find_char(start, end, 'e');
					top->construct_int(int_start, start - int_start);
					if (start == end) TORRENT_FAIL_BDECODE(errors::unexpected_eof);
					TORRENT_ASSERT(*start == 'e');
					++start;
					stack.pop_back();
					continue;
				}
				default:
				{
					if (!is_digit(t)) TORRENT_FAIL_BDECODE(errors::expected_value);

					boost::int64_t len = t - '0';
					start = parse_int(start, end, ':', len);
					if (start == 0 || start + len + 1 > end || *start != ':')
						TORRENT_FAIL_BDECODE(errors::expected_colon);
					++start;
					top->construct_string(start, int(len));
					stack.pop_back();
					start += len;
//.........这里部分代码省略.........

	std::string print_entry(lazy_entry const& e, bool single_line, int indent)
	{
		char indent_str[200];
		memset(indent_str, ' ', 200);
		indent_str[0] = ',';
		indent_str[1] = '\n';
		indent_str[199] = 0;
		if (indent < 197 && indent >= 0) indent_str[indent+2] = 0;
		std::string ret;
		switch (e.type())
		{
			case lazy_entry::none_t: return "none";
			case lazy_entry::int_t:
			{
				char str[100];
				snprintf(str, sizeof(str), "%"PRId64, e.int_value());
				return str;
			}
			case lazy_entry::string_t:
			{
				bool printable = true;
				char const* str = e.string_ptr();
				for (int i = 0; i < e.string_length(); ++i)
				{
					using namespace std;
					if (is_print((unsigned char)str[i])) continue;
					printable = false;
					break;
				}
				ret += "'";
				if (printable)
				{
					ret += e.string_value();
					ret += "'";
					return ret;
				}
				for (int i = 0; i < e.string_length(); ++i)
				{
					char tmp[5];
					snprintf(tmp, sizeof(tmp), "%02x", (unsigned char)str[i]);
					ret += tmp;
				}
				ret += "'";
				return ret;
			}
			case lazy_entry::list_t:
			{
				ret += '[';
				bool one_liner = line_longer_than(e, 200) != -1 || single_line;

				if (!one_liner) ret += indent_str + 1;
				for (int i = 0; i < e.list_size(); ++i)
				{
					if (i == 0 && one_liner) ret += " ";
					ret += print_entry(*e.list_at(i), single_line, indent + 2);
					if (i < e.list_size() - 1) ret += (one_liner?", ":indent_str);
					else ret += (one_liner?" ":indent_str+1);
				}
				ret += "]";
				return ret;
			}
			case lazy_entry::dict_t:
			{
				ret += "{";
				bool one_liner = line_longer_than(e, 200) != -1 || single_line;

				if (!one_liner) ret += indent_str+1;
				for (int i = 0; i < e.dict_size(); ++i)
				{
					if (i == 0 && one_liner) ret += " ";
					std::pair<std::string, lazy_entry const*> ent = e.dict_at(i);
					ret += "'";
					ret += ent.first;
					ret += "': ";
					ret += print_entry(*ent.second, single_line, indent + 2);
					if (i < e.dict_size() - 1) ret += (one_liner?", ":indent_str);
					else ret += (one_liner?" ":indent_str+1);
				}
				ret += "}";
				return ret;
			}
		}
		return ret;
	}

std::string print_entry(lazy_entry const& e, bool single_line, int indent)
{
    char indent_str[200];
    memset(indent_str, ' ', 200);
    indent_str[0] = ',';
    indent_str[1] = '\n';
    indent_str[199] = 0;
    if (indent < 197 && indent >= 0) indent_str[indent+2] = 0;
    std::string ret;
    switch (e.type())
    {
    case lazy_entry::none_t:
        return "none";
    case lazy_entry::int_t:
    {
        char str[100];
        std::snprintf(str, sizeof(str), "%" PRId64, e.int_value());
        return str;
    }
    case lazy_entry::string_t:
    {
        print_string(ret, e.string_ptr(), e.string_length(), single_line);
        return ret;
    }
    case lazy_entry::list_t:
    {
        ret += '[';
        bool one_liner = line_longer_than(e, 200) != -1 || single_line;

        if (!one_liner) ret += indent_str + 1;
        for (int i = 0; i < e.list_size(); ++i)
        {
            if (i == 0 && one_liner) ret += " ";
            ret += print_entry(*e.list_at(i), single_line, indent + 2);
            if (i < e.list_size() - 1) ret += (one_liner?", ":indent_str);
            else ret += (one_liner?" ":indent_str+1);
        }
        ret += "]";
        return ret;
    }
    case lazy_entry::dict_t:
    {
        ret += "{";
        bool one_liner = line_longer_than(e, 200) != -1 || single_line;

        if (!one_liner) ret += indent_str+1;
        for (int i = 0; i < e.dict_size(); ++i)
        {
            if (i == 0 && one_liner) ret += " ";
            std::pair<std::string, lazy_entry const*> ent = e.dict_at(i);
            print_string(ret, ent.first.c_str(), int(ent.first.size()), true);
            ret += ": ";
            ret += print_entry(*ent.second, single_line, indent + 2);
            if (i < e.dict_size() - 1) ret += (one_liner?", ":indent_str);
            else ret += (one_liner?" ":indent_str+1);
        }
        ret += "}";
        return ret;
    }
    }
    return ret;
}

// return 0 = success
int lazy_bdecode(char const* start, char const* end, lazy_entry& ret
                 , error_code& ec, int* error_pos, int depth_limit, int item_limit)
{
    char const* const orig_start = start;
    ret.clear();

    std::vector<lazy_entry*> stack;

    if (start == end)
        TORRENT_FAIL_BDECODE(bdecode_errors::unexpected_eof);

    stack.push_back(&ret);
    while (start <= end)
    {
        if (stack.empty()) break; // done!

        lazy_entry* top = stack.back();

        if (int(stack.size()) > depth_limit) TORRENT_FAIL_BDECODE(bdecode_errors::depth_exceeded);
        if (start >= end) TORRENT_FAIL_BDECODE(bdecode_errors::unexpected_eof);
        char t = *start;
        ++start;
        if (start >= end && t != 'e') TORRENT_FAIL_BDECODE(bdecode_errors::unexpected_eof);

        switch (top->type())
        {
        case lazy_entry::dict_t:
        {
            if (t == 'e')
            {
                top->set_end(start);
                stack.pop_back();
                continue;
            }
            if (!numeric(t)) TORRENT_FAIL_BDECODE(bdecode_errors::expected_digit);
            std::int64_t len = t - '0';
            bdecode_errors::error_code_enum e = bdecode_errors::no_error;
            start = parse_int(start, end, ':', len, e);
            if (e)
                TORRENT_FAIL_BDECODE(e);

            // remaining buffer size excluding ':'
            const ptrdiff_t buff_size = end - start - 1;
            if (len > buff_size)
                TORRENT_FAIL_BDECODE(bdecode_errors::unexpected_eof);

            if (len < 0)
                TORRENT_FAIL_BDECODE(bdecode_errors::overflow);

            ++start;
            if (start == end) TORRENT_FAIL_BDECODE(bdecode_errors::unexpected_eof);
            lazy_entry* ent = top->dict_append(start);
            if (ent == nullptr) TORRENT_FAIL_BDECODE(boost::system::errc::not_enough_memory);
            start += len;
            if (start >= end) TORRENT_FAIL_BDECODE(bdecode_errors::unexpected_eof);
            stack.push_back(ent);
            t = *start;
            ++start;
            break;
        }
        case lazy_entry::list_t:
        {
            if (t == 'e')
            {
                top->set_end(start);
                stack.pop_back();
                continue;
            }
            lazy_entry* ent = top->list_append();
            if (ent == nullptr) TORRENT_FAIL_BDECODE(boost::system::errc::not_enough_memory);
            stack.push_back(ent);
            break;
        }
        case lazy_entry::int_t:
        case lazy_entry::string_t:
        case lazy_entry::none_t:
            break;
        }

        --item_limit;
        if (item_limit <= 0) TORRENT_FAIL_BDECODE(bdecode_errors::limit_exceeded);

        top = stack.back();
        switch (t)
        {
        case 'd':
            top->construct_dict(start - 1);
            break;
        case 'l':
            top->construct_list(start - 1);
            break;
        case 'i':
        {
            char const* int_start = start;
            start = find_char(start, end, 'e');
            top->construct_int(int_start, start - int_start);
            if (start == end) TORRENT_FAIL_BDECODE(bdecode_errors::unexpected_eof);
            TORRENT_ASSERT(*start == 'e');
            ++start;
//.........这里部分代码省略.........