/cpp-lib

General purpose and aviation-related C++ library

Primary LanguageC++

README for cpp-lib

What is it?

Cpp-lib is a general purpose library of ISO C++ functions and classes. It is provided free of charge and without any implied warranty by KISS Technologies GmbH, Switzerland under an Apache license.

Documentation

Documentation is by comments in the header files, we may move to doxygen in the future. See also the tests for example usage.

Components

Cpp-lib is organized into the components listed below.

Each header file has a comment of the form

// Component: <component name>

at its top. UNSUPPORTED is used for functions used only internally or not ready for production.

AERONAUTICS

  • Open Glider Network (APRS and DDB) client
  • IGC file parsing

CGI

  • CGI parameter parsing and URI unescaping

CRYPT

  • A block cipher (blowfish).
  • A streambuf filter for transparent reading and writing of encrypted files based on arbitrary block ciphers in cipher feedback mode (CFB).

DISPATCH

  • A dispatch queue, modeled after Grand Central Dispatch (GCD)

GNSS

  • Latitude/Longitude/Altitude data structure and related functions.
  • Undulation conversion between WGS84 and MSL altitudes (Earth Geoid Model, function geoid_height()).
  • A geographic database with spatial search and openAIP input (suitable for airport reference points).

HTTP

  • A very simple HTTP client

MAP

  • Web Mercator tile mapping

MATH

  • Some components are based on the [Eigen] 10 matrix library.
  • 3-dimensional geometry, quaternions, Euler angles, etc.
  • ODE solvers and some state-space modeling blocks.
  • Unconstrained multidimensional minimization with gradients (a C++ version of [minimize] 4).
  • Unconstrained multidimensional minimization without gradients (see [Nelder/Mead] 5, downhill simplex, [Wolfram] 7).
  • A spatial index based on boost::rtree.

NETWORK

  • Easy TCP/IP and UDP connections. Iostreams implementation for TCP streams. See README-networking for more information.
  • A framework for running TCP services, optionally using threads.

TABLE

  • Arbitrary dimensional tables with dimension defined at runtime.
  • A choice of algorithms for multidimensional interpolation.

REALTIME

  • Realtime scheduling.

REGISTRY

  • A versatile configuration file parser with flexible syntax including arbitrarily nested lists. Configurable grammar for various pre-existing configuration file styles (C style, Matlab style, shell style, ...). Transparent reading of encrypted files.

SYSUTIL

  • Iostream compatible logging to syslog(3)
  • File modification time, alerts on modified files and a registry version with on-the-fly reloading of modified files.
  • Simple timekeeping and sleep() calls.
  • Powering off and rebooting the computer.
  • A powerful syslog(3)-based logging facility.

UTIL

  • A class for command line parsing. Snpports long and short-name options with or without arguments.
  • Generic stream buffer templates.
  • Resource handler templates.
  • Physical constants and units.

VARLIST

  • Bind names to variables and provide serialization.

Namespaces/component association

  • cpl::crypt : CRYPT

  • cpl::dispatch : DISPATCH

  • cpl::gnss : GNSS

  • cpl::igc : AERONAUTICS

  • cpl::ogn : AERONAUTICS

  • cpl::map : MAP

  • cpl::math : MATH

  • cpl::util : UTIL, VARLIST, REGISTRY, REALTIME, SYSUTIL

  • cpl::units : UTIL

  • cpl::util::container : UTIL

  • cpl::util::file : SYSUTIL

  • cpl::util::log : SYSUTIL

  • cpl::util::network : NETWORK

  • cpl::detail_ : Private namespace for implementation details. Do not use those in client code.

Error reporting

Errors are reported as exceptions derived from std::exception with a meaningful what() message.

Supported platforms

Cpp-lib is written in ISO C++ and makes use of C++14 features. Due to multiple problems with GNU g++, we currently recommend clang++ (October 2015).

  • clang++: Based on LLVM 3.5.0 or higher (MacOS X and Linux).
  • The Microsoft Visual Studio Express (C++) and CYGWIN builds are looking for maintainers.

It is generally possible to use subsets of cpp-lib independently, e.g. for embedded applications.

Building cpp-lib

Dependencies

  • A C++ compiler supporting C++14 or later (Tested: clang++)
  • GNU make (BSD make does not work)
  • The [BOOST] 1 header files (version 1.58.0 or higher).
  • The [Eigen] 10 library
  • If PNG_STUFF is enabled: [libpng] 8 and [png++] 9

See Tested Versions below.

On old Ubuntu versions (14.04), it is currently necessary to install the Boost source code directly from here: http://sourceforge.net/projects/boost/files/boost/1.60.0/boost_1_60_0.tar.bz2 It is not necessary to compile Boost.

Boost, png++ and Eigen are used in a header-only way.

  • Installing dependencies on Ubuntu:

    • sudo apt-get install libeigen3-dev
    • sudo apt-get install libpng++-dev

  • Installing clang++ on Ubuntu (example: Version 3.6):

    • sudo apt-get install clang-3.6
    • sudo apt-get install libc++-dev
    • sudo apt-get install libc++abi-dev

  • Installing g++-5 on old Ubuntu versions (e.g. 14.04): sudo add-apt-repository ppa:ubuntu-toolchain-r/test sudo apt-get update sudo apt-get install g++-5

Tested versions

  • Boost: 1.58.0, 1.60.0 (#include "boost/version.hpp")
  • libpng: 1.2.50, 1.6.18 (libpng-config --version)
  • png++: 0.2.5
  • Eigen: 3.2.5

Build

  • cd prj

  • Create symbolic links appropriate for your system or copy the files:

Setup on Ubuntu

ln -s def.compiler.clang-3.6 def.compiler
ln -s def.platform.linux-clang-libc++ def.platform

Setup on MacOS X (Darwin)

ln -s def.compiler.clang def.compiler
ln -s def.platform.darwin def.platform

Compile

  • make -j4 tests to build the library and tests.

  • Use export debug=true; make; make tests to build a debug version of the library and the tests. Release and debug versions are kept in separate directories.

Always use the same debug setting (true or false) for make, make tests and make clean.

Test

cd testing/

./run-all-tests.sh

Test output is written to testing/data/golden-output. Run git diff to look out for unexpected changes.

Clean

Use make clean to delete object files and executables.

The supplied Makefile assumes GNU make.

The Makefile is based on separate configuration of compiler (file def.compiler), platform (def.platform) and include files (def.includes).

Examples are provided for certain supported platforms and compilers (including cross compilation with MinGW). See def.platform.* and def.compiler.*. Not all combinations make sense!

The library and tests will be built under .../cpp-lib/build/$(PLATFORM) . Note that many tests use input files, which are found in .../cpp-lib/testing.

The def.platform.* files set the variables WINDOWS_STUFF, POSIX_STUFF and POSIX1B_STUFF to yes to include the respective platform-specific functionality. Exactly one of WINDOWS_STUFF or POSIX_STUFF must be set to yes.

WINDOWS_STUFF indicates that cpp-lib should use the Microsoft Windows API, POSIX_STUFF the POSIX (SUSv3) API. Note that the target operating system may be Windows while the POSIX API is used, as is the case for the cygwin environment.

Depending on the platform settings, the Makefile will create symbolic links (or copies for compilers which don't support symbolic links) of the respective platform subdirectories in the source and header directories to platform and platform_rt, resp.

BOOST notes

Set BOOST_INCLUDES in def.includes to point to your BOOST header files.

If you use a cross compiler, it may be preferable to have a separate set of BOOST header files (i.e., not under /usr/include).

Windows compilation notes

GNU make is available e.g. in [cygwin] 2.

No project for the Visual Studio .NET IDE is supplied. To compile using the Microsoft C++ compiler, start the Visual Studio .NET command prompt and cygwin from it (typically, enter c:\cygwin\cygwin). This procedure ensures that the environment variables for the compiler are visible inside the cygwin environment.

Code using the Windows API (WINDOWS_STUFF set to yes) assumes that the WIN32 preprocessor symbol is set.

FreeBSD compilation notes

The default make utility of FreeBSD is not GNU make. You need to install and use the gmake port.

Using cpp-lib in your own code

Headers for client code are in include/cpp-lib and include/cpp-lib/sys.

Use #include "cpp-lib/xyz.h" in your code and set the include path to cpp-lib/include in your project.

Do not include anything from the the platform-specific subdirectories of include/cpp-lib (currently, posix/, posix1b/ and windows/).

It is possible to use just parts of cpp-lib. To do so, add the required individual cpp-lib sources and headers to your project. This way you can achieve fine-grained control over the dependencies.
E.g., it's possible to use MATH, UTIL and CRYPT without BOOST.

Debug builds

Many functions in cpp-lib are rather short inline functions. It may make debugging easier if inlining is switched off for debug builds. On g++, use -fno-inline.

Directory structure

  • src/ C++ sources (.cpp).
  • include/cpp-lib/ C++ headers (.h).
  • testing/ Test/example programs.
  • testing/data/ Test data and golden output.
  • prj/ Makefiles and platform/compiler definition files.
  • obj/ Build directory, created by the makefile.
  • obj/{opt,dbg} Object files and libraries.
  • bin/{opt,dbg} Executable files

Caveats

Some mathematical algorithms, notably the minimize() function, depend on the availability of floating point representations of infinity and not-a-number. Most modern platforms satisfy this requirement.

The realtime_scheduler class may only be instantiated once per process on POSIX systems.

Bugs

Please see TODO.

Coding style

  • General: Stick with the style of code around you.

  • Lines no longer than 80 characters.

  • Two characters indentation.

  • No tabs, use spaces instead.

  • UNIX line endings.

  • C++ style comments (//).

  • lower_case_and_underscore style.

Library design principles

  • Performance and ease of use.

  • Realtime guarantee: Generally, data structures and algorithms are designed to allocate all resources at initialization time.

  • Seamless integration with the C++ standard library. E.g., the TCP and serial interface provide standard C++ streambufs.

  • RAII (resource acquisition is initialization). Constructors either yield a ready-to-use object or throw.

  • Better safe than sorry. Assertions even in tight loops.

  • Platform independency, not multiplatform dependency. Avoid #ifdef _LINUX_/WIN32/etc. mess, but rather factor out minimal generic interfaces for platform-specific functionality (see e.g. posix/wrappers.cpp and windows/wrappers.cpp)

  • Orthogonality/DRY: Don't repeat yourself

Commit guidelines

  • Please follow the library design guidelines above.

  • Commits that add or change functionality should be kept small and with well readable diffs for code review.

  • To achieve the above, isolate as much as possible of the work in 'zero functional change' (ZFC) commits. That is, refactor before you add or change functionality.

  • Any whitespace changes should be in a separate ZFC commit.

  • Make sure that ZFC commits don't change any test results or break tests.

  • Add test cases for new functionality, modify test cases for modified functionality.

References

See also

See README-networking for information on the TCP/IP and UDP classes.

Copyright

Cpp-lib is copyright (C) 2014 and onwards, KISS Technologies GmbH and its contributors. Please give due credit when using it. Please see the file LICENSE-2.0.txt for details.

OpenAIP data is owned by Butterfly Avionics GmbH and licensed under the CC BY-NC-SA. Cpp-lib uses a small amount of openAIP data for testing purposes.