Read data into a streambuf until a function object indicates a match.
template< typename SyncReadStream, typename Allocator, typename MatchCondition> std::size_t read_until( SyncReadStream & s, boost::asio::basic_streambuf< Allocator > & b, MatchCondition match_condition, boost::system::error_code & ec, typename constraint< is_match_condition< MatchCondition >::value >::type = 0);
This function is used to 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 call will block until one of the following conditions is true:
This operation is implemented in terms of zero or more calls to the stream's read_some function. If the match condition function object already indicates a match, the function returns immediately.
The stream from which the data is to be read. The type must support the SyncReadStream concept.
A streambuf object into which the data will be read.
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);
iterator represents the type:
The iterator parameters
the range of bytes to be scanned to determine whether there is a
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
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.
Set to indicate what error occurred, if any.
The number of bytes in the streambuf's get area that have been fully consumed by the match function. Returns 0 if an error occurred.
After a successful 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 read_until operation to examine.
The default implementation of the
trait evaluates to true for function pointers and function objects with
result_type typedef. It must be specialised for other user-defined