stringio - TextIO Derivative using string

Browse Header stringio.hpp
Introduction
Output Strings
Input Strings

Introduction

Sometimes it is useful to be able to redirect output or source input from an in-memory string. That is the purpose of this package. It provides costomisations for the TextIO input and output devices that work on a single string.

Note that for large I/O requirements, the string_vectorio package might be more appropriate.

Output Strings

Usage

The most common and simplest way of using string output devices is to used the derived class ostext. This is a derivation of otext and can be used wherever otext would be used. For example:

ostext my_output;

Once an output string device has been opened, it can be used as the base class otext device, giving access to all of the output chevron operators (<<). See the TextIO Documentation for details.

For example:

my_output << "Hello World" << endl;

This fills in the string with the text "Hello World\n".

The internal string which receives the output text can be accessed by the get_string function.

string& result = my_output.get_string();

The string output device has the same newline conversion functions as any TextIO output device, so the '\n' character can be mapped onto any OS-specific convention. For example:

ostext my_output;
my_output.set_newline_mode(textio_output_unix);

This example forces Unix conventions on the output string.

Input Strings

Usage

Input files are used in a very similar way to output files. The main difference is that, with input strings, the input device needs to be initialised with the string contents by passing a string to the constructor.

For example:

istext my_input("Hello World");

This device can now be used as an input to a chevron expression to extract the elements of the string. For example, the >> operator for a string gets the next non-whitespace sequence from a device. Thus the words can be split very easily:

string first_word;
my_input >> first_word;
string second_word;
my_input >> second_word;

The input string device has the concept of end-of-file in that the device eof() function returns true if all of the string has been read.