Landon Curt Noll
cbc022d864
The inc/footer.default.html now has a common Copyright and CC BY-SA 4.0 License section for all generated HTML files. All markdown files have a similar Copyright and CC at the bottom in the form of an HTML comment.
307 lines
15 KiB
HTML
307 lines
15 KiB
HTML
<!DOCTYPE html>
|
||
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
|
||
<!-- START: two lines up starts content from: inc/top.default.html -->
|
||
<!-- -->
|
||
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->
|
||
<!-- !!! DO NOT MODIFY THIS FILE - This file is generated by a tool !!! -->
|
||
<!-- !!! DO NOT MODIFY THIS FILE - This file is generated by a tool !!! -->
|
||
<!-- !!! DO NOT MODIFY THIS FILE - This file is generated by a tool !!! -->
|
||
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->
|
||
<!-- -->
|
||
<!-- END: this line ends content from: inc/top.default.html -->
|
||
<!-- -->
|
||
<!-- This web page was formed via the tool: bin/readme2index.sh -->
|
||
<!-- -->
|
||
<!-- The content of main section of this web page came from: 2015/hou/README.md -->
|
||
<!-- -->
|
||
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->
|
||
<!-- !!! Do not modify this web page, instead modify the file: 2015/hou/README.md -->
|
||
<!-- !!! Do not modify this web page, instead modify the file: 2015/hou/README.md -->
|
||
<!-- !!! Do not modify this web page, instead modify the file: 2015/hou/README.md -->
|
||
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->
|
||
<!-- -->
|
||
<!-- Markdown content was converted into HTML via the tool: bin/md2html.sh -->
|
||
<!-- -->
|
||
<!-- START: this line starts content from: inc/head.default.html -->
|
||
|
||
<head>
|
||
<link rel="stylesheet" href="../../ioccc.css">
|
||
<meta charset="utf-8">
|
||
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
|
||
<title>2015/hou - Most Well-rounded Hash</title>
|
||
<meta name="description" content="2015 IOCCC entry hou - Most Well-rounded Hash">
|
||
<meta name="keywords" content="IOCCC, 2015, IOCCC 2015, IOCCC entry, hou, Most Well-rounded Hash">
|
||
</head>
|
||
|
||
<!-- END: this line ends content from: inc/head.default.html -->
|
||
<!-- START: this line starts content from: inc/body.default.html -->
|
||
|
||
<body>
|
||
|
||
<!-- END: this line ends content from: inc/body.default.html -->
|
||
<!-- START: this line starts content from: inc/header.default.html -->
|
||
|
||
<div class="header">
|
||
<img src="../../png/ioccc.png" alt="IOCCC image by Matt Zucker" width=300 height=110>
|
||
<h1>The International Obfuscated C Code Contest</h1>
|
||
<h2>2015/hou - Most Well-rounded Hash</h2>
|
||
</div>
|
||
|
||
<!-- END: this line ends content from: inc/header.default.html -->
|
||
<!-- START: this line starts content from: inc/topnav.mid.html -->
|
||
|
||
<div class="topnav">
|
||
<a class="Left" href="../endoh4/index.html">← endoh4</a>
|
||
<a class="Left" href="../index.html">↑ 2015 ↑</a>
|
||
<a class="Left" href="../howe/index.html">howe →</a>
|
||
<a class="Right" href="https://github.com/ioccc-src/temp-test-ioccc/2015/hou/prog.c">C code</a>
|
||
<a class="Right" href="https://github.com/ioccc-src/temp-test-ioccc/2015/hou/Makefile">Makefile</a>
|
||
<a class="Right" href="#inventory">Inventory</a>
|
||
</div>
|
||
|
||
<!-- END: this line ends content from: inc/topnav.mid.html -->
|
||
<!-- START: this line starts content from: inc/begin-row.default.html -->
|
||
|
||
<div class="row">
|
||
|
||
<!-- END: this line ends content from: inc/begin-row.default.html -->
|
||
<!-- START: this line starts content from: inc/begin-leftcolumn.default.html -->
|
||
|
||
<div class="leftcolumn">
|
||
|
||
<!-- END: this line ends content from: inc/begin-leftcolumn.default.html -->
|
||
<!-- START: this line starts content from: inc/sidenav.default.html -->
|
||
|
||
<div class="sidenav">
|
||
<a href="#content">Jump to contents</a>
|
||
</div>
|
||
<hr>
|
||
<div class="sidenav">
|
||
<a href="../../index.html">IOCCC Home</a>
|
||
<a href="../../years.html">Winning Entries</a>
|
||
<a href="../../authors.html">People who have won</a>
|
||
<a href="../../location.html">Location of authors</a>
|
||
</div>
|
||
<hr>
|
||
<div class="sidenav">
|
||
<a href="../../news.html">IOCCC News</a>
|
||
<a href="../../status.html">Contest status</a>
|
||
<a href="../../faq.html#submit">How to enter the IOCCC</a>
|
||
<a href="../../faq.html">FAQ</a>
|
||
</div>
|
||
<hr>
|
||
<div class="sidenav">
|
||
<a href="../../bugs.html">Bugs & (mis)features</a>
|
||
<a href="../../faq.html#fix_an_entry">Fixing IOCCC entries</a>
|
||
<a href="../../faq.html#fix_web_site">Fixing the web site</a>
|
||
<a href="../../faq.html#fix_author">Fixing author info</a>
|
||
<a href="../../thanks-for-help.html">Thanks for the help</a>
|
||
</div>
|
||
<hr>
|
||
<div class="sidenav">
|
||
<a href="../../judges.html">The IOCCC Judges</a>
|
||
<a href="../../contact.html">Contacting the IOCCC</a>
|
||
</div>
|
||
<hr>
|
||
<div class="sidenav">
|
||
<a href="#top">Jump to top</a>
|
||
</div>
|
||
|
||
<!-- END: this line ends content from: inc/sidenav.default.html -->
|
||
<!-- START: this line starts content from: inc/end-leftcolumn.default.html -->
|
||
|
||
</div>
|
||
|
||
<!-- END: this line ends content from: inc/end-leftcolumn.default.html -->
|
||
<!-- START: this line starts content from: inc/begin-rightcolumn.default.html -->
|
||
|
||
<div class="rightcolumn">
|
||
|
||
<!-- END: this line ends content from: inc/begin-rightcolumn.default.html -->
|
||
<!-- START: this line starts content from: inc/before-content.default.html -->
|
||
|
||
<a name="content"></a>
|
||
|
||
<!-- END: this line ends content from: inc/before-content.default.html -->
|
||
<!-- START: this line starts content for HTML phase 20 by: bin/output-index-author.sh via bin/md2html.sh -->
|
||
|
||
<!-- START: this line starts content generated by: bin/output-index-author.sh -->
|
||
|
||
<h2 id="author"><a name="author"></a>Author:</h2>
|
||
<ul>
|
||
<li>Name: <a href="../../authors.html#Qiming_HOU">Qiming HOU</a><br>
|
||
Location: <a href="../../location.html#CN">CN</a> - <em>People’s Republic of China</em> (<em>China</em>)
|
||
<br><br></li>
|
||
</ul>
|
||
|
||
<!-- END: next line ends content generated by: bin/output-index-author.sh -->
|
||
|
||
<!-- END: this line ends content for HTML phase 20 by: bin/output-index-author.sh via bin/md2html.sh -->
|
||
<!-- START: this line starts content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
|
||
|
||
<h2 id="to-build">To build:</h2>
|
||
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="fu">make</span></span></code></pre></div>
|
||
<h3 id="bugs-and-misfeatures">Bugs and (Mis)features:</h3>
|
||
<p>The current status of this entry is:</p>
|
||
<pre><code>STATUS: INABIAF - please **DO NOT** fix</code></pre>
|
||
<p>For more detailed information see <a href="../../bugs.html#2015_hou">2015 hou bugs</a>.</p>
|
||
<h2 id="to-use">To use:</h2>
|
||
<div class="sourceCode" id="cb3"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb3-1"><a href="#cb3-1" aria-hidden="true" tabindex="-1"></a><span class="bu">echo</span> something <span class="kw">|</span> <span class="ex">./prog</span></span>
|
||
<span id="cb3-2"><a href="#cb3-2" aria-hidden="true" tabindex="-1"></a><span class="ex">./prog</span> <span class="op"><</span> file</span></code></pre></div>
|
||
<h2 id="try">Try:</h2>
|
||
<div class="sourceCode" id="cb4"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb4-1"><a href="#cb4-1" aria-hidden="true" tabindex="-1"></a><span class="ex">./try.sh</span></span></code></pre></div>
|
||
<h2 id="judges-remarks">Judges’ remarks:</h2>
|
||
<p>A good start for understanding this entry might be
|
||
<a href="rfc1321.txt">rfc1321.txt</a>. How does it compute this using only a
|
||
single looping construct? The original reference source code for this
|
||
algorithm is about 355 lines of code, yet this entry is only 199 lines with
|
||
one statement per line and it isn’t using lots of macro expansion tricks like
|
||
the reference code!</p>
|
||
<p>Some things that make you go, “huh?”</p>
|
||
<div class="sourceCode" id="cb5"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb5-1"><a href="#cb5-1" aria-hidden="true" tabindex="-1"></a><span class="ex">./prog</span> <span class="op"><</span> prog.c <span class="kw">|</span> <span class="fu">cut</span> <span class="at">-c-5</span></span>
|
||
<span id="cb5-2"><a href="#cb5-2" aria-hidden="true" tabindex="-1"></a><span class="ex">./prog</span> <span class="op"><</span> Makefile <span class="kw">|</span> <span class="fu">cut</span> <span class="at">-c-4</span></span></code></pre></div>
|
||
<p>How are those values magically returned?</p>
|
||
<p>What happens with a large file? Something over 256K.</p>
|
||
<div class="sourceCode" id="cb6"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a><span class="ex">./prog</span> <span class="op"><</span> large_file</span></code></pre></div>
|
||
<p>Where does that message come from?</p>
|
||
<h2 id="authors-remarks">Author’s remarks:</h2>
|
||
<p>This looks like a normal C program.</p>
|
||
<p>Almost everything is a <code>double</code>.</p>
|
||
<p>There are tell-tale signs like <code>pow(2,(?/12))</code> and <code>exp(-?*?)</code> (names redacted).
|
||
You can also find a bunch of cosines and polynomial evaluations.</p>
|
||
<p>It looks like a ????? ???????????, right?</p>
|
||
<p>Run and find out.</p>
|
||
<h3 id="why-obfuscated">Why obfuscated</h3>
|
||
<p>Some poor scripting folks only have access to doubles (Jav?script, L?a, BA?IC,
|
||
etc.).</p>
|
||
<p>As a C programmer, I feel obliged to show a gesture of sympathy, to experience
|
||
their pain and provide an answer.</p>
|
||
<p>Except when absolutely necessary (<code>printf</code>, <code>int main()</code>, array indexing), there
|
||
isn’t a single integer. Even <code>getchar()</code> and <code>EOF</code> are immediately converted.</p>
|
||
<p>Since <code>bool</code> counts as an integer type too, there is no boolean either. No
|
||
comparison, no <code>if</code>, no <code>?:</code>, no <code>||</code> <code>&&</code>. Everything is done in a single loop
|
||
that terminates on <code>printf(3)</code>. Straight up arithmetic.</p>
|
||
<p><code>floor(3)</code> and <code>ceil(3)</code> are technically double-to-double functions, but they feel
|
||
like cheating. Yes <code>cos(3)</code>, no <code>floor(3)</code>.</p>
|
||
<h3 id="limitations">Limitations</h3>
|
||
<p>Hard requirements:</p>
|
||
<ul>
|
||
<li><p>The platform must implement the <code>double</code> type as IEEE754-compliant 64-bit
|
||
floating point numbers. The 80-bit intermediate format used by x87 is
|
||
considered as an violation of this. The code should print an error message on
|
||
such platforms.</p></li>
|
||
<li><p>The program must start with the CPU / FPU in round-to-nearest mode.</p></li>
|
||
</ul>
|
||
<p>Soft requirements:</p>
|
||
<ul>
|
||
<li><p>The compiler must respect <code>volatile</code>. The code is formatted to warn about
|
||
that, though.</p></li>
|
||
<li><p>The printed result is only correct on little-endian machines. The program
|
||
takes care to warn about this issue after printing an incorrect big-endian
|
||
result. Error messages become garbled, though.</p></li>
|
||
</ul>
|
||
<p>Tested platforms:</p>
|
||
<ul>
|
||
<li>Linux 3.18.7, Rasperberry Pi 2, clang 3.0-6.2, (works)</li>
|
||
<li>Linux 3.18.7, Rasperberry Pi 2, gcc 4.6.3, (works)</li>
|
||
<li>Mac OS X 10, x64, Apple LLVM version 6.1.0 (clang-602.0.53), (works)</li>
|
||
<li>Windows 8.1, x86, MSVC 2012 (works)<br />
|
||
</li>
|
||
<li>Windows 8.1, x64, MSVC 2012 (works)</li>
|
||
<li>Windows 8.1, x86, MinGW gcc 4.6.2 (fails, prints error message)</li>
|
||
<li>Windows 8.1, x86, MinGW gcc 4.6.2 with -msse2 -mfpmath=sse (works)</li>
|
||
</ul>
|
||
<!--
|
||
|
||
Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.
|
||
|
||
You are free to share and adapt this file under the terms of this license:
|
||
|
||
Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
|
||
|
||
For more information, see:
|
||
|
||
https://creativecommons.org/licenses/by-sa/4.0/
|
||
|
||
-->
|
||
|
||
<!-- END: this line ends content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
|
||
<!-- START: this line starts content for HTML phase 22 by: bin/output-index-inventory.sh via bin/md2html.sh -->
|
||
|
||
<!-- START: this line starts content generated by: bin/output-index-inventory.sh -->
|
||
|
||
<h1 id="inventory-for-2015hou"><a name="inventory"></a>Inventory for 2015/hou</h1>
|
||
<p><a href="#top">Jump to top</a></p>
|
||
<h2 id="primary-files">Primary files</h2>
|
||
<ul>
|
||
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/hou/prog.c">prog.c</a> - entry source</li>
|
||
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/hou/Makefile">Makefile</a> - entry Makefile</li>
|
||
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/hou/prog.orig.c">prog.orig.c</a> - original source</li>
|
||
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/hou/try.sh">try.sh</a> - how to run</li>
|
||
<li><a href="rfc1321.txt">rfc1321.txt</a> - RFC 1321 - MD5 Message-Digest Algorithm</li>
|
||
<li><a href="2015_hou.tar.bz2">2015_hou.tar.bz2</a> - download entry source</li>
|
||
</ul>
|
||
<h2 id="secondary-files">Secondary files</h2>
|
||
<ul>
|
||
<li><a href="index.html">index.html</a> - entry home page</li>
|
||
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/hou/README.md">README.md</a> - markdown source for index.html</li>
|
||
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/hou/.entry.json">.entry.json</a> - description of entry in JSON</li>
|
||
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/hou/.gitignore">.gitignore</a> - list of files that should not be committed under git</li>
|
||
<li><a href="large">large</a> - large input data</li>
|
||
<li><a href=".path">.path</a> - directory path from top directory</li>
|
||
</ul>
|
||
|
||
<!-- END: next line ends content generated by: bin/output-index-inventory.sh -->
|
||
|
||
<!-- END: this line ends content for HTML phase 22 by: bin/output-index-inventory.sh via bin/md2html.sh -->
|
||
<!-- START: this line starts content from: inc/after-content.default.html -->
|
||
|
||
<!-- END: this line ends content from: inc/after-content.default.html -->
|
||
<!-- START: this line starts content from: inc/end-rightcolumn.default.html -->
|
||
|
||
</div>
|
||
|
||
<!-- END: this line ends content from: inc/end-rightcolumn.default.html -->
|
||
<!-- START: this line starts content from: inc/end-row.default.html -->
|
||
|
||
</div>
|
||
|
||
<!-- END: this line ends content from: inc/end-row.default.html -->
|
||
<!-- START: this line starts content from: inc/footer.default.html -->
|
||
|
||
<!--
|
||
|
||
Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.
|
||
|
||
You are free to share and adapt this file under the terms of this license:
|
||
|
||
Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
|
||
|
||
For more information, see:
|
||
|
||
https://creativecommons.org/licenses/by-sa/4.0/
|
||
|
||
-->
|
||
|
||
<div class="footer">
|
||
<h2>Copyright and CC BY-SA 4.0 License</h2>
|
||
<p>This file and web page is:</p>
|
||
<blockquote><b>Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.</b></p></blockquote>
|
||
<p>You are free to share and adapt this file under the terms of this license:</p>
|
||
<blockquote><b>Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)</b></blockquote>
|
||
<p>For more information, see:</p>
|
||
<blockquote><a
|
||
href="https://creativecommons.org/licenses/by-sa/4.0/">https://creativecommons.org/licenses/by-sa/4.0/</a></blockquote>
|
||
<h2>Coda</h2>
|
||
<p><a href="https://validator.w3.org/nu/?doc=https%3A%2F%2Fioccc-src.github.io%2Ftemp-test-ioccc%2F2015%2Fhou%2Findex.html">Nu HTML check this web page</a></p>
|
||
<p><a href="#top">Jump to top</a> <a href="#content">Jump to Content</a> <a href="#inventory">Jump to Inventory</a></p>
|
||
</div>
|
||
|
||
<!-- END: this line ends content from: inc/footer.default.html -->
|
||
<!-- START: this line starts content from: inc/bottom.default.html -->
|
||
|
||
</body>
|
||
</html>
|
||
|
||
<!-- END: this line ends content from: inc/bottom.default.html -->
|