Backdown

Backdown is a Markdown parser based on the original code of the vmg/sundown by Vicent Marti.

Installation

• Dynamic Library
• Static Library
• Executable Files

Just type make.

Features

• Fully standards compliant

  Backdown passes out of the box the official Markdown v1.0.0 and v1.0.3 test suites, and has been extensively tested with additional corner cases to make sure its output is as sane as possible at all times.

• Massive extension support

  Backdown has optional support for several (unofficial) Markdown extensions, such as non-strict emphasis, fenced code blocks, tables, autolinks, strikethrough and more.

• UTF-8 aware

  Backdown is fully UTF-8 aware, both when parsing the source document and when generating the resulting (X)HTML code.

• Tested & Ready to be used on production

  Backdown has been extensively security audited, and includes protection against all possible DOS attacks (stack overflows, out of memory situations, malformed Markdown syntax...) and against client attacks through malicious embedded HTML.

  We've worked very hard to make Backdown never crash or run out of memory under any input. Backdown renders all the Markdown content in GitHub and so far hasn't crashed a single time.

• Customizable renderers

  Backdown is not stuck with XHTML output: the Markdown parser of the library is decoupled from the renderer, so it's trivial to extend the library with custom renderers. A fully functional (X)HTML renderer is included.

• Optimized for speed

  Backdown is written in C, with a special emphasis on performance. When wrapped on a dynamic language such as Python or Ruby, it has shown to be up to 40 times faster than other native alternatives.

• Zero-dependency

  Backdown is a zero-dependency library composed of 3 .c files and their headers. No dependencies, no bullshit. Only standard C99 that builds everywhere.

Help us

Backdown is all about security. If you find a (potential) security vulnerability in the library, or a way to make it crash through malicious input, please report it to us, either directly via email or by opening an Issue on GitHub, and help make the web safer for everybody.

Unicode character handling

Given that the Markdown spec makes no provision for Unicode character handling, Backdown takes a conservative approach towards deciding which extended characters trigger Markdown features:

• Punctuation characters outside of the U+007F codepoint are not handled as punctuation. They are considered as normal, in-word characters for word-boundary checks.

• Whitespace characters outside of the U+007F codepoint are not considered as whitespace. They are considered as normal, in-word characters for word-boundary checks.

License

The MIT License (MIT)

Maintainer

Shintaro Kaneko [email protected]