IniPP

Simple header-only C++ ini parser and generator.

Features

• Header-only.
• Both parsing and generating.
• Wide character support for native unicode on Windows.
• Default section support (similar to Python’s ConfigParser).
• Interpolation support (i.e. variable substitution, similar to Python’s ConfigParser).
• Trailing comments support.
• Simple design and implementation.
• Permissive MIT license.

Example

#include <fstream>
#include "inipp.h"

int main() {
    inipp::Ini<char> ini;
    std::ifstream is("example.ini");
    ini.parse(is);
    std::cout << "raw ini file:" << std::endl;
    ini.generate(std::cout);
    ini.strip_trailing_comments();
    ini.default_section(ini.sections["DEFAULT"]);
    ini.interpolate();
    std::cout << "ini file after default section and interpolation:" << std::endl;
    ini.generate(std::cout);
    int compression_level = -1;
    inipp::get_value(ini.sections["bitbucket.org"], "CompressionLevel", compression_level);
    std::cout << "bitbucket.org compression level: " << compression_level << std::endl;
    return 0;
}

To include in a cmake project:

FetchContent_Declare(inipp GIT_REPOSITORY https://github.com/mcmtroffaes/inipp.git)
FetchContent_MakeAvailable(inipp)
target_link_libraries(MyTarget PRIVATE inipp::inipp)

Parsing algorithm

• The section is set to the empty string.

• Every line is read from the file and trimmed from whitespace.

  • If line is empty or starts with ; then nothing happens.

  • Otherwise, if line starts with [ then section is changed to the string between [ and ]. If line does not end with ] then an error is reported.

  • Otherwise, if line contains an = sign, then all characters before = are treated as variable and all characters following = are treated as value. Both are trimmed. If the variable was already assigned earlier, an error is reported. Otherwise, the corresponding assigment is added to the section.

  • Otherwise, the line is reported as an error.

Default section algorithm

Insert every variable from the default section into every other section, without overwriting existing variables.

Interpolation algorithm

1. Locally within each section, every occurrence “$variable\mathrm{"}isreplacedby\mathrm{"}\{variable\}"\; is\; replaced\; by\; "${section:variable}”.
2. Every occurrence of “${section:variable}” is replaced by its value.
3. The previous step is repeated until no more replacements are possible, or until the recursion depth (by default, 10) is reached.