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Sundown is a Markdown parser based on the original code of theUpskirt library by Natacha Porté.

• Fully standards compliant

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

• Massive extension support

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

• UTF-8 aware

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

• Tested & Ready to be used on production

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

  We've worked very hard to makeSundown never crash or run out of memoryunderany input.Sundown renders all the Markdown content in GitHub and sofar hasn't crashed a single time.

• Customizable renderers

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

• Optimized for speed

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

• Zero-dependency

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

Sundown is based on the original Upskirt parser by Natacha Porté, with many additionsby Vicent Marti (@vmg) and contributions from the following authors:

Ben Noordhuis, Bruno Michel, Joseph Koshy, Krzysztof Kowalczyk, Samuel Bronson,Shuhei Tanuma

Sundown is available from other programming languages thanks to these bindings developedby our awesome contributors.

• Redcarpet (Ruby)
• RobotSkirt (Node.js)
• Misaka (Python)
• ffi-sundown (Ruby FFI)
• Sundown HS (Haskell)
• Goskirt (Go)
• Upskirt.go (Go)
• MoonShine (.NET)
• PHP-Sundown (PHP)
• Sundown.net (.NET)

Sundown is all about security. If you find a (potential) security vulnerability in thelibrary, 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 saferfor everybody.

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

• 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 aswhitespace. They are considered as normal, in-word characters for word-boundary checks.

There is nothing to install.Sundown is composed of 3.c files (markdown.c,buffer.c andarray.c), so just throw them in your project. Zero-dependency meanszero-dependency. You might want to includerender/html.c if you want to use theincluded XHTML renderer, or write your own renderer. Either way, it's all fun and joy.

If you are hardcore, you can use the includedMakefile to buildSundown into a dynamiclibrary, or to build the samplesundown executable, which is just a commandlineMarkdown to XHTML parser. (If gcc gives you grief about-fPIC, e.g. with MinGW, trymake MFLAGS= instead of justmake.)

Permission to use, copy, modify, and distribute this software for anypurpose with or without fee is hereby granted, provided that the abovecopyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIESWITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OFMERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FORANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGESWHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN ANACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OFOR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.