argo::reader Class Reference

A class to read JSON messages from various types of input stream. More...

#include <reader.hpp>

Inheritance diagram for argo::reader:

Public Member Functions
	reader (size_t max_message_length, bool block_read)
virtual int	next ()
	Get the next character from the reader. More...
virtual void	put_back (int c)
	Put back a character so that it is returned by the next call to next().
size_t	get_byte_index () const
	Get the current byte index in the input.
void	reset_byte_index ()
	Reset the byte index at the start of parsing a messege.

Static Public Attributes
static const int	block_size = 8192
	Amount of data to read at once when in block read mode.

Protected Member Functions
int	read_next_char_from_block ()
	When in block read mode, get the next available character.
virtual int	read_next_char ()=0
	Implemented by derived classes to do the actual reading.
virtual bool	read_next_block ()=0

Protected Attributes
int	m_put_back
	Character last put back. If equal to no_put_back then none was.
size_t	m_byte_index
	Total number of characters read.
size_t	m_max_message_length
	Maximum length of a message.
bool	m_block_read
	Whether to read in blocks or one byte at a time.
unsigned char	m_block [block_size]
	If we're reading blocks, the block data.
int	m_block_num_bytes
	If we're reading blocks, the number of bytes in the current block.
int	m_block_index
	If we're reading blocks, the index into the current block.

Static Protected Attributes
static const int	no_put_back = 1000
	Special character value indicating that no character has been put back.

Detailed Description

A class to read JSON messages from various types of input stream.

A class that acts as a proxy for the various places that JSON messages can be parsed from (or from which they can be parsed even). The base class tracks how many characters have been read and handles put back logic, actually reading from somewhere is in in derived classes.

Definition at line 42 of file reader.hpp.

Constructor & Destructor Documentation

reader::reader	(	size_t	max_message_length,
		bool	block_read
	)

Constructor.

Parameters

max_message_length	maximum number bytes to be read in total
block_read	if true read in blocks, if false read one byte at a time

Definition at line 31 of file reader.cpp.

Member Function Documentation

int reader::next ( )

virtual

Get the next character from the reader.

Returns

A character or EOF on end of file.

Exceptions

json_io_exception	after an IO error of some type.
json_parser_exception	if the message is too long

Definition at line 54 of file reader.cpp.

virtual bool argo::reader::read_next_block ( )

protectedpure virtual

Implemented by derived classes to read the next block of data up to block_size bytes.

Returns

true if some data was read, false if EOF.

Exceptions

json_io_error

if the read failed for some reason other than EOF.

Implemented in argo::file_reader, argo::stream_reader, and argo::fd_reader.

---

The documentation for this class was generated from the following files:

• reader.hpp
• reader.cpp