Start an asynchronous operation to read data into a streambuf until it contains a delimiter, matches a regular expression, or a function object indicates a match. More...

Functions
template<typename AsyncReadStream , typename Allocator , typename ReadHandler >
void	asio::async_read_until (AsyncReadStream &s, asio::basic_streambuf< Allocator > &b, char delim, ReadHandler handler)
template<typename AsyncReadStream , typename Allocator , typename ReadHandler >
void	asio::async_read_until (AsyncReadStream &s, asio::basic_streambuf< Allocator > &b, const std::string &delim, ReadHandler handler)
template<typename AsyncReadStream , typename Allocator , typename ReadHandler >
void	asio::async_read_until (AsyncReadStream &s, asio::basic_streambuf< Allocator > &b, const boost::regex &expr, ReadHandler handler)
template<typename AsyncReadStream , typename Allocator , typename MatchCondition , typename ReadHandler >
void	asio::async_read_until (AsyncReadStream &s, asio::basic_streambuf< Allocator > &b, MatchCondition match_condition, ReadHandler handler, typename boost::enable_if< is_match_condition< MatchCondition > >::type *=0)

Detailed Description

Start an asynchronous operation to read data into a streambuf until it contains a delimiter, matches a regular expression, or a function object indicates a match.

Function Documentation

template<typename AsyncReadStream , typename Allocator , typename ReadHandler >

void asio::async_read_until	(	AsyncReadStream &	s,
		asio::basic_streambuf< Allocator > &	b,
		char	delim,
		ReadHandler	handler
	)

Start an asynchronous operation to read data into a streambuf until it contains a specified delimiter. This function is used to asynchronously read data into the specified streambuf until the streambuf's get area contains the specified delimiter. The function call always returns immediately. The asynchronous operation will continue until one of the following conditions is true:

The get area of the streambuf contains the specified delimiter.

An error occurred.

This operation is implemented in terms of zero or more calls to the stream's async_read_some function. If the streambuf's get area already contains the delimiter, the asynchronous operation completes immediately.

Parameters:

s	The stream from which the data is to be read. The type must support the AsyncReadStream concept.
b	A streambuf object into which the data will be read. Ownership of the streambuf is retained by the caller, which must guarantee that it remains valid until the handler is called.
delim	The delimiter character.
handler	The handler to be called when the read operation completes. Copies will be made of the handler as required. The function signature of the handler must be: void handler( // Result of operation. const asio::error_code& error, // The number of bytes in the streambuf's get // area up to and including the delimiter. // 0 if an error occurred. std::size_t bytes_transferred ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using asio::io_service::post().

Note:: After a successful async_read_until operation, the streambuf may contain additional data beyond the delimiter. An application will typically leave that data in the streambuf for a subsequent async_read_until operation to examine.

Example

To asynchronously read data into a streambuf until a newline is encountered:

 asio::streambuf b;
 ...
 void handler(const asio::error_code& e, std::size_t size)
 {
   if (!e)
   {
     std::istream is(&b);
     std::string line;
     std::getline(is, line);
     ...
   }
 }
 ...
 asio::async_read_until(s, b, '\n', handler);

template<typename AsyncReadStream , typename Allocator , typename ReadHandler >

void asio::async_read_until	(	AsyncReadStream &	s,
		asio::basic_streambuf< Allocator > &	b,
		const std::string &	delim,
		ReadHandler	handler
	)

Start an asynchronous operation to read data into a streambuf until it contains a specified delimiter. This function is used to asynchronously read data into the specified streambuf until the streambuf's get area contains the specified delimiter. The function call always returns immediately. The asynchronous operation will continue until one of the following conditions is true:

The get area of the streambuf contains the specified delimiter.

An error occurred.

This operation is implemented in terms of zero or more calls to the stream's async_read_some function. If the streambuf's get area already contains the delimiter, the asynchronous operation completes immediately.

Parameters:

s	The stream from which the data is to be read. The type must support the AsyncReadStream concept.
b	A streambuf object into which the data will be read. Ownership of the streambuf is retained by the caller, which must guarantee that it remains valid until the handler is called.
delim	The delimiter string.
handler	The handler to be called when the read operation completes. Copies will be made of the handler as required. The function signature of the handler must be: void handler( // Result of operation. const asio::error_code& error, // The number of bytes in the streambuf's get // area up to and including the delimiter. // 0 if an error occurred. std::size_t bytes_transferred ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using asio::io_service::post().

Note:: After a successful async_read_until operation, the streambuf may contain additional data beyond the delimiter. An application will typically leave that data in the streambuf for a subsequent async_read_until operation to examine.

Example

To asynchronously read data into a streambuf until a newline is encountered:

 asio::streambuf b;
 ...
 void handler(const asio::error_code& e, std::size_t size)
 {
   if (!e)
   {
     std::istream is(&b);
     std::string line;
     std::getline(is, line);
     ...
   }
 }
 ...
 asio::async_read_until(s, b, "\r\n", handler);

template<typename AsyncReadStream , typename Allocator , typename ReadHandler >

void asio::async_read_until	(	AsyncReadStream &	s,
		asio::basic_streambuf< Allocator > &	b,
		const boost::regex &	expr,
		ReadHandler	handler
	)

Start an asynchronous operation to read data into a streambuf until some part of its data matches a regular expression. This function is used to asynchronously read data into the specified streambuf until the streambuf's get area contains some data that matches a regular expression. The function call always returns immediately. The asynchronous operation will continue until one of the following conditions is true:

A substring of the streambuf's get area matches the regular expression.

An error occurred.

This operation is implemented in terms of zero or more calls to the stream's async_read_some function. If the streambuf's get area already contains data that matches the regular expression, the function returns immediately.

Parameters:

s	The stream from which the data is to be read. The type must support the AsyncReadStream concept.
b	A streambuf object into which the data will be read. Ownership of the streambuf is retained by the caller, which must guarantee that it remains valid until the handler is called.
expr	The regular expression.
handler	The handler to be called when the read operation completes. Copies will be made of the handler as required. The function signature of the handler must be: void handler( // Result of operation. const asio::error_code& error, // The number of bytes in the streambuf's get // area up to and including the substring // that matches the regular. expression. // 0 if an error occurred. std::size_t bytes_transferred ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using asio::io_service::post().

Note:: After a successful async_read_until operation, the streambuf may contain additional data beyond that which matched the regular expression. An application will typically leave that data in the streambuf for a subsequent async_read_until operation to examine.

Example

To asynchronously read data into a streambuf until a CR-LF sequence is encountered:

 asio::streambuf b;
 ...
 void handler(const asio::error_code& e, std::size_t size)
 {
   if (!e)
   {
     std::istream is(&b);
     std::string line;
     std::getline(is, line);
     ...
   }
 }
 ...
 asio::async_read_until(s, b, boost::regex("\r\n"), handler);

template<typename AsyncReadStream , typename Allocator , typename MatchCondition , typename ReadHandler >

void asio::async_read_until	(	AsyncReadStream &	s,
		asio::basic_streambuf< Allocator > &	b,
		MatchCondition	match_condition,
		ReadHandler	handler,
		typename boost::enable_if< is_match_condition< MatchCondition > >::type *	= `0`
	)

Start an asynchronous operation to read data into a streambuf until a function object indicates a match. This function is used to asynchronously read data into the specified streambuf until a user-defined match condition function object, when applied to the data contained in the streambuf, indicates a successful match. The function call always returns immediately. The asynchronous operation will continue until one of the following conditions is true:

The match condition function object returns a std::pair where the second element evaluates to true.

An error occurred.

This operation is implemented in terms of zero or more calls to the stream's async_read_some function. If the match condition function object already indicates a match, the operation completes immediately.

Parameters:

s	The stream from which the data is to be read. The type must support the AsyncReadStream concept.
b	A streambuf object into which the data will be read.
match_condition	The function object to be called to determine whether a match exists. The signature of the function object must be: pair<iterator, bool> match_condition(iterator begin, iterator end); where `iterator` represents the type: buffers_iterator<basic_streambuf<Allocator>::const_buffers_type> The iterator parameters `begin` and `end` define the range of bytes to be scanned to determine whether there is a match. The `first` member of the return value is an iterator marking one-past-the-end of the bytes that have been consumed by the match function. This iterator is used to calculate the `begin` parameter for any subsequent invocation of the match condition. The `second` member of the return value is true if a match has been found, false otherwise.
handler	The handler to be called when the read operation completes. Copies will be made of the handler as required. The function signature of the handler must be: void handler( // Result of operation. const asio::error_code& error, // The number of bytes in the streambuf's get // area that have been fully consumed by the // match function. O if an error occurred. std::size_t bytes_transferred ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using asio::io_service::post().

Note:: After a successful async_read_until operation, the streambuf may contain additional data beyond that which matched the function object. An application will typically leave that data in the streambuf for a subsequent async_read_until operation to examine.; The default implementation of the is_match_condition type trait evaluates to true for function pointers and function objects with a result_type typedef. It must be specialised for other user-defined function objects.

Examples

To asynchronously read data into a streambuf until whitespace is encountered:

 typedef asio::buffers_iterator<
     asio::streambuf::const_buffers_type> iterator;

 std::pair<iterator, bool>
 match_whitespace(iterator begin, iterator end)
 {
   iterator i = begin;
   while (i != end)
     if (std::isspace(*i++))
       return std::make_pair(i, true);
   return std::make_pair(i, false);
 }
 ...
 void handler(const asio::error_code& e, std::size_t size);
 ...
 asio::streambuf b;
 asio::async_read_until(s, b, match_whitespace, handler);

To asynchronously read data into a streambuf until a matching character is found:

 class match_char
 {
 public:
   explicit match_char(char c) : c_(c) {}

   template <typename Iterator>
   std::pair<Iterator, bool> operator()(
       Iterator begin, Iterator end) const
   {
     Iterator i = begin;
     while (i != end)
       if (c_ == *i++)
         return std::make_pair(i, true);
     return std::make_pair(i, false);
   }

 private:
   char c_;
 };

 namespace asio {
   template <> struct is_match_condition<match_char>
     : public boost::true_type {};
 } // namespace asio
 ...
 void handler(const asio::error_code& e, std::size_t size);
 ...
 asio::streambuf b;
 asio::async_read_until(s, b, match_char('a'), handler);

Functions

Detailed Description

Function Documentation