embtextf: Embedded System Text Formatting

embtextf is a collection of functions supporting *printf(3c) and numeric formatting functionality on embedded devices with highly constrained memory. It derives from functions originally provided in msp430-libc from the MSPGCC project.

Features include:

• The base embtextf_vuprintf() function supports *printf(3c) compatible output through a caller-provided callback function that handles each formatted character as it is produced. This approach eliminates the need for large internal buffers to hold the constructed data;

• The supported format-string capabilities cover most non-floating-point format specifiers and modifiers, with some compile-time control to mediate between features and required code space;

• Mixed-Base Integer to String Conversion Functions format int and long values into a caller-provided buffer in any radix from base 2 to base 36;

• Option (via EMBTEXTF_PROVIDE_LIBC) to build ISO C-compatible wrappers that replace libc functionality with embtextf implementations, saving up to 20KB of relative to other libc implementations;

• The entire family of *printf(3c) functions takes between 1KB and 3KB of code depending on target processor and feature selection.

The conversions operate on native C types, abstracting away from word size and byte order. The module has been tested on both 16- and 32-bit microcontrollers.

Each provided function is prefixed with embtextf_ to isolate it from both the toolchain and application namespaces. This allows embtextf to co-exist with toolchains like mspgcc, which provide the same functionality in a compatible way, and others like Code Composer Studio or toolchains using newlib which provide similarly named functions with different semantics, interfaces, or memory expectations. The application program can use the preprocessor to redirect unqualified names to the embtextf implementations.

For installation instructions see Installation and Use.

The project page is at http://github.com/pabigot/embtextf. Releases can be obtained by cloning the git repository:

git clone git://github.com/pabigot/embtextf.git

or by downloading a tar file of the complete source.

Please file support requests and bug reports on the issue tracker.

Homepage

http://github.com/pabigot/embtextf

Copyright

Copyright 2011-2013, Peter A. Bigot. embtextf_vuprintf() contains material copyright 2006-2011, Chris Liechti. Licensed under BSD-3-Clause