Files
ioccc/2020/kurdyukov1/index.html
T
Landon Curt Noll a1c86c8a7a add original C links to entry navigation bars
The navigation bar for a winning entry now has a "_Original C_" link
(between the ✅ and the Inventory on the right hand side) so that one
may easily view the original C code that was submitted for IOCCC judging.

Ran `make www timestamp` to perform the above.
2025-08-10 12:46:23 -07:00

671 lines
24 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
<!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 -->
<!-- END: this line ends content from: inc/top.default.html -->
<!-- START: this line starts content from: inc/head.default.html -->
<head>
<link rel="stylesheet" href="../../ioccc.css">
<link href="https://fonts.googleapis.com/css2?family=Outfit:wght@100..900&display=swap" rel="stylesheet">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<title>2020/kurdyukov1 - Best utility</title>
<link rel="icon" type="image/x-icon" href="../../favicon.ico">
<meta name="description" content="2020 IOCCC entry kurdyukov1 - Best utility">
<meta name="keywords" content="IOCCC, 2020, IOCCC 2020, IOCCC entry, kurdyukov1, Best utility">
</head>
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->
<!-- !!! 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/head.default.html -->
<!-- -->
<!-- This web page was formed via the tool: bin/readme2index.sh -->
<!-- The content of main section of this web page came from: 2020/kurdyukov1/README.md -->
<!-- -->
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->
<!-- !!! Do not modify this web page, instead modify the file: 2020/kurdyukov1/README.md !!! -->
<!-- !!! Do not modify this web page, instead modify the file: 2020/kurdyukov1/README.md !!! -->
<!-- !!! Do not modify this web page, instead modify the file: 2020/kurdyukov1/README.md !!! -->
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->
<!-- Markdown content was converted into HTML via the tool: bin/md2html.sh -->
<!-- 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/topbar.default.html -->
<div class="theader">
<nav class="topbar">
<div class="container">
<div class="logo">
<a href="../../index.html" class="logo-link">
IOCCC
</a>
</div>
<div class="topbar-items">
<div class="item">
<span class="item-header">
Entries
</span>
<div class="sub-item">
<div class="outfit-font">
<a href="../../years.html" class="sub-item-link">
Winning entries
</a>
</div>
<div class="outfit-font">
<a href="../../authors.html" class="sub-item-link">
Winning authors
</a>
</div>
<div class="outfit-font">
<a href="../../location.html" class="sub-item-link">
Location of authors
</a>
</div>
<div class="outfit-font">
<a href="../../bugs.html" class="sub-item-link">
Bugs and (mis)features
</a>
</div>
<div class="outfit-font">
<a href="../../faq.html#fix_an_entry" class="sub-item-link">
Fixing entries
</a>
</div>
<div class="outfit-font">
<a href="../../faq.html#fix_author" class="sub-item-link">
Updating author info
</a>
</div>
</div>
</div>
<div class="item">
<span class="item-header">
Status
</span>
<div class="sub-item">
<div class="outfit-font">
<a href="../../news.html" class="sub-item-link">
News
</a>
</div>
<div class="outfit-font">
<a href="../../status.html" class="sub-item-link">
Contest status
</a>
</div>
<div class="outfit-font">
<a href="../../next/rules.html" class="sub-item-link">
IOCCC rules
</a>
</div>
<div class="outfit-font">
<a href="../../next/guidelines.html" class="sub-item-link">
IOCCC guidelines
</a>
</div>
<div class="outfit-font">
<a href="../../markdown.html" class="sub-item-link">
Markdown guidelines
</a>
</div>
<div class="outfit-font">
<a href="../../SECURITY.html" class="sub-item-link">
Security policy
</a>
</div>
</div>
</div>
<div class="item">
<span class="item-header">
FAQ
</span>
<div class="sub-item">
<div class="outfit-font">
<a href="../../faq.html" class="sub-item-link">
Frequently asked questions
</a>
</div>
<div class="outfit-font">
<a href="../../quick-start.html#enter" class="sub-item-link">
Enter the IOCCC
</a>
</div>
<div class="outfit-font">
<a href="../../faq.html#compiling" class="sub-item-link">
Compiling entries
</a>
</div>
<div class="outfit-font">
<a href="../../faq.html#running_entries" class="sub-item-link">
Running entries
</a>
</div>
<div class="outfit-font">
<a href="../../faq.html#help" class="sub-item-link">
How to help
</a>
</div>
</div>
</div>
<div class="item">
<span class="item-header">
About
</span>
<div class="sub-item">
<div class="outfit-font">
<a href="../../index.html" class="sub-item-link">
Home page
</a>
</div>
<div class="outfit-font">
<a href="../../social.html" class="sub-item-link">
IOCCC social media
</a>
</div>
<div class="outfit-font">
<a href="../../about.html" class="sub-item-link">
About the IOCCC
</a>
</div>
<div class="outfit-font">
<a href="../../judges.html" class="sub-item-link">
The judges
</a>
</div>
<div class="outfit-font">
<a href="../../thanks-for-help.html" class="sub-item-link">
Thanks for the help
</a>
</div>
<div class="outfit-font">
<a href="../../contact.html" class="sub-item-link">
Contact us
</a>
</div>
</div>
</div>
</div>
</div>
</nav>
<div class="header-mobile-menu">
<noscript>
<a href="../../nojs-menu.html" class="topbar-js-label">
Please Enable JavaScript
</a>
</noscript>
<button id="header-open-menu-button" class="topbar-mobile-menu">
<img
src="../../png/hamburger-icon-open.png"
alt="hamburger style menu icon - open state"
width=48
height=48>
</button>
<button id="header-close-menu-button" class="hide-content">
<img
src="../../png/hamburger-icon-closed.png"
alt="hamburger style menu icon - closed state"
width=48
height=48>
</button>
<div id="mobile-menu-panel" class="hide-content">
<div class="mobile-menu-container">
<div class="mobile-menu-wrapper">
<div class="mobile-menu-item">
Entries
</div>
<div class="mobile-submenu-wrapper">
<a class="mobile-submenu-item" href="../../years.html">
Winning entries
</a>
<a class="mobile-submenu-item" href="../../authors.html">
Winning authors
</a>
<a class="mobile-submenu-item" href="../../location.html">
Location of authors
</a>
<a class="mobile-submenu-item" href="../../bugs.html">
Bugs and (mis)features
</a>
<a class="mobile-submenu-item" href="../../faq.html#fix_an_entry">
Fixing entries
</a>
<a class="mobile-submenu-item" href="../../faq.html#fix_author">
Updating author info
</a>
<a class="mobile-submenu-item" href="../../thanks-for-help.html">
Thanks for the help
</a>
</div>
</div>
<div class="mobile-menu-wrapper">
<div class="mobile-menu-item">
Status
</div>
<div class="mobile-submenu-wrapper">
<a class="mobile-submenu-item" href="../../news.html">
News
</a>
<a class="mobile-submenu-item" href="../../status.html">
Contest status
</a>
<a class="mobile-submenu-item" href="../../next/rules.html">
IOCCC rules
</a>
<a class="mobile-submenu-item" href="../../next/guidelines.html">
IOCCC guidelines
</a>
<a class="mobile-submenu-item" href="../../markdown.html">
Markdown guidelines
</a>
<a class="mobile-submenu-item" href="../../SECURITY.html">
Security policy
</a>
</div>
</div>
<div class="mobile-menu-wrapper">
<div class="mobile-menu-item">
FAQ
</div>
<div class="mobile-submenu-wrapper">
<a class="mobile-submenu-item" href="../../faq.html">
Frequently asked questions
</a>
<a class="mobile-submenu-item" href="../../quick-start.html#enter">
Enter the IOCCC
</a>
<a class="mobile-submenu-item" href="../../faq.html#compiling">
Compiling entries
</a>
<a class="mobile-submenu-item" href="../../faq.html#running_entries">
Running entries
</a>
<a class="mobile-submenu-item" href="../../faq.html#help">
How to help
</a>
</div>
</div>
<div class="mobile-menu-wrapper">
<div class="mobile-menu-item">
About
</div>
<div class="mobile-submenu-wrapper">
<a class="mobile-submenu-item" href="../../index.html">
Home page
</a>
<a class="mobile-submenu-item" href="../../social.html">
IOCCC social media
</a>
<a class="mobile-submenu-item" href="../../about.html">
About the IOCCC
</a>
<a class="mobile-submenu-item" href="../../judges.html">
The judges
</a>
<a class="mobile-submenu-item" href="../../contact.html">
Contact us
</a>
</div>
</div>
</div>
</div>
</div>
</div>
<script>
var headerOpenMenuButton = document.getElementById("header-open-menu-button");
var headerCloseMenuButton = document.getElementById("header-close-menu-button");
var mobileMenuPanel = document.getElementById("mobile-menu-panel");
headerOpenMenuButton.addEventListener("click", () => {
headerOpenMenuButton.classList.remove("topbar-mobile-menu");
headerOpenMenuButton.classList.add("hide-content");
headerCloseMenuButton.classList.remove("hide-content");
headerCloseMenuButton.classList.add("topbar-mobile-menu");
mobileMenuPanel.classList.remove("hide-content");
mobileMenuPanel.classList.add("topbar-mobile-panel");
});
headerCloseMenuButton.addEventListener("click", () => {
headerCloseMenuButton.classList.remove("topbar-mobile-menu");
headerCloseMenuButton.classList.add("hide-content");
mobileMenuPanel.classList.add("hide-content");
mobileMenuPanel.classList.remove("topbar-mobile-panel");
headerOpenMenuButton.classList.add("topbar-mobile-menu");
headerOpenMenuButton.classList.remove("hide-content");
});
</script>
<!-- END: this line ends content from: inc/topbar.default.html -->
<!-- START: this line starts content from: inc/header.default.html -->
<div class="header">
<a href="../../2011/zucker/index.html">
<img src="../../png/ioccc.png"
alt="IOCCC image by Matt Zucker"
width=300
height=110>
</a>
<h1>The International Obfuscated C Code Contest</h1>
<h2>2020/kurdyukov1 - Best utility</h2>
<h3>MD5 checksum</h3>
</div>
<!-- END: this line ends content from: inc/header.default.html -->
<!-- START: this line starts content from: inc/navbar.mid.html -->
<div class="navbar">
<a class="Left" href="../giles/index.html">&larr; 2020/giles</a>
<a class="Left" href="../index.html">&uarr; 2020 &uarr;</a>
<a class="Left" href="../kurdyukov2/index.html">2020/kurdyukov2 &rarr;</a>
<a class="Right" href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.c">C code</a>
<a class="Right" href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/Makefile">Makefile</a>
<a class="Right" href="#inventory">Inventory</a>
<a class="Right" href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.orig.c">Original C</a>
<a class="Right" href="https://validator.w3.org/nu/?doc=https%3A%2F%2Fwww.ioccc.org%2F2020%2Fkurdyukov1%2Findex.html">&#x2713;</a>
</div>
<!-- END: this line ends content from: inc/navbar.mid.html -->
<!-- START: this line starts content from: inc/before-content.default.html -->
<div class="content" id="content">
<!-- 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">Author:</h2>
<ul>
<li>Name: <a href="../../authors.html#Ilya_Kurdyukov">Ilya Kurdyukov</a><br>
Location: <a href="../../location.html#RU">RU</a> - <em>Russian Federation</em> (<em>Russia</em>)</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 -->
<!-- BEFORE: 1st line of markdown file: 2020/kurdyukov1/README.md -->
<h2 id="to-build">To build:</h2>
<pre><code> make</code></pre>
<p>There are alternate versions of this entry. See <a href="#alternate-code">Alternate
code</a> below for more details.</p>
<h2 id="to-use">To use:</h2>
<pre><code> ./prog
# input some text
echo text | ./prog
./prog &lt; file</code></pre>
<h2 id="try">Try:</h2>
<pre><code> ./try.sh</code></pre>
<h2 id="alternate-code">Alternate code:</h2>
<p>There are a number of alternate versions for this program, some in C and some in
assembly.</p>
<p>The file <a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.alt.c">prog.alt.c</a> is smaller and does not contain any
headers or any workaround for WIN32 based platforms.</p>
<p>The file <a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.extra.c">prog.extra.c</a> has a number of layouts including some for
different social media profile covers as well as different shapes.</p>
<p>The files <a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.x86_64.asm">prog.x86_64.asm</a> and <a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.x86.asm">prog.x86.asm</a>
are the program in assembly for x86_64 linux and x86 linux respectively.</p>
<h3 id="alternate-build">Alternate build:</h3>
<p>To build <a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.alt.c">prog.alt.c</a>:</p>
<pre><code> make alt</code></pre>
<h3 id="alternate-use">Alternate use:</h3>
<p>Use <code>prog.alt</code> as you would <code>prog</code> above.</p>
<h2 id="judges-remarks">Judges’ remarks:</h2>
<p>This hash of a C code makes a hash out of input.
Do you understand how?
You should get a-round-to-it figuring it out!</p>
<h2 id="authors-remarks">Author’s remarks:</h2>
<h3 id="md5-with-integers">MD5 with integers</h3>
<p>Just a tiny MD5 checksum utility. Prints hash string of data from <code>stdin</code>.
Works the same as <code>openssl md5 | cut -d' ' -f2</code> command.</p>
<h3 id="my-objectives">My objectives</h3>
<ol type="1">
<li>Reduce code size as much as possible.</li>
<li>Avoid warnings from gcc/clang <code>-Wall -Wextra -pedantic</code>.</li>
<li>Portable (regardless of register size and endianness).</li>
<li>Fit code in a round shape.</li>
<li>Mo macro defines.</li>
<li>No floating-point arithmetics.</li>
</ol>
<h3 id="notes">Notes</h3>
<p>The main difficulty of making MD5 code smaller is a 64x4 bytes long table with
constants which will take more than 512 bytes in hex encoding. This table is a
results of a sine function, so can be generated dynamically, but merging
floating-point arithmetics with precise integer calculations is not a great
idea, because it can cause portability issues.</p>
<p>Attempts to satisfy <code>clang -Weverything</code> will ruin comma magic, that is so great
for obfuscation, so I don’t want to care about that.</p>
<p>Probably, should work correctly on any machines, but I have nothing exotic (like
BE or not 32/64) to try it.</p>
<p>Added a macro hack to make <code>stdin</code> work in binary mode under Windows (tested
under mingw64), otherwise the hashes can be incorrect.</p>
<h3 id="bonus">Bonus</h3>
<ul>
<li><p><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.extra.c">prog.extra.c</a> is the same with the sine function (so smaller),
and in different shapes.</p></li>
<li><p><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.x86_64.asm">prog.x86_64.asm</a> contains the same program, but written in
assembly for x86_64 Linux, for the sake of smaller executable size which is 500
bytes long (where 120 is for the ELF headers) after compilation. Algorithm
details is slightly different (like constants packing), just to make smaller
binary code. It’s interesting to compare density of binary code and obfuscated</p></li>
</ul>
<ol start="3" type="A">
<li></li>
</ol>
<ul>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.x86.asm">prog.x86.asm</a> is for x86, although the headers are smaller, but
the binary code is larger due to fewer registers and lack of 64-bit multiply.</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/
-->
<!-- AFTER: last line of markdown file: 2020/kurdyukov1/README.md -->
<!-- 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 -->
<div id="inventory">
<h1 id="inventory-for-2020kurdyukov1">Inventory for 2020/kurdyukov1</h1>
</div>
<h2 id="primary-files">Primary files</h2>
<ul>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.c">prog.c</a> - entry source code</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/Makefile">Makefile</a> - entry Makefile</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.alt.c">prog.alt.c</a> - alternate source code</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.orig.c">prog.orig.c</a> - original source code</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/try.sh">try.sh</a> - script to try entry</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.extra.c">prog.extra.c</a> - variant of entry source code with sine function</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.x86_64.asm">prog.x86_64.asm</a> - x86_64 assembly source code</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/prog.x86.asm">prog.x86.asm</a> - x86 assembly source code</li>
</ul>
<h2 id="secondary-files">Secondary files</h2>
<ul>
<li><a href="2020_kurdyukov1.tar.bz2">2020_kurdyukov1.tar.bz2</a> - download entry tarball</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/README.md">README.md</a> - markdown source for this web page</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/.entry.json">.entry.json</a> - entry summary and manifest in JSON</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/.gitignore">.gitignore</a> - list of files that should not be committed under git</li>
<li><a href="https://github.com/ioccc-src/winner/blob/master/2020/kurdyukov1/.path">.path</a> - directory path from top level directory</li>
<li><a href="index.html">index.html</a> - this web page</li>
</ul>
<hr style="width:10%;text-align:left;margin-left:0">
<h4>
Jump to: <a href="#">top</a>
</h4>
<!-- 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 -->
</div>
<!-- END: this line ends content from: inc/after-content.default.html -->
<!-- START: this line starts content from: inc/footer.inventory.html -->
<!--
Copyright © 1984-2025 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">
<div id="copyright"><h3>Copyright &copy; 1984-2025 by Landon Curt Noll:
<a href="https://creativecommons.org/faq/#what-does-some-rights-reserved-mean"
target="_blank"
rel="license noopener noreferrer">Some Rights Reserved</a></h3>
<p>
This work is <b>licensed by Landon Curt Noll</b> under
<b><a href="https://creativecommons.org/licenses/by-sa/4.0/?ref=chooser-v1"
target="_blank"
rel="license noopener noreferrer"
style="display:inline-block;">CC BY-SA 4.0</a></b>.
<img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;"
src="../../png/cc.png"
alt="cc inside circle symbol">
<img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;"
src="../../png/by.png"
alt="person inside circle symbol">
<img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;"
src="../../png/sa.png"
alt="arrow looping back on itself inside circle symbol"><br>
You should <b>carefully review</b> the
<b><a href="https://creativecommons.org/licenses/by-sa/4.0/legalcode.en"
target="_blank"
rel="license noopener noreferrer">CC BY-SA 4.0 LEGAL CODE</a></b>
before using the licensed material.<br>
You may wish to review the
<b><a href="../../license.html"
target="_blank"
rel="license noopener noreferrer">highlights of some of the key features and terms</a></b>
of <b>CC BY-SA 4.0</b>.<br>
</p>
</div>
<div id="coda"><h3>Coda</h3>
<p>
<a href="https://validator.w3.org/nu/?doc=https%3A%2F%2Fwww.ioccc.org%2F2020%2Fkurdyukov1%2Findex.html" rel="nofollow">Nu HTML check this web page</a><br>
<a href="#top">Jump to top</a> <a href="#content">Jump to Content</a> <a href="#inventory">Jump to Inventory</a><br>
</p>
</div>
</div>
<!-- END: this line ends content from: inc/footer.inventory.html -->
<!-- START: this line starts content from: inc/bottom.default.html -->
</body>
</html>
<!-- END: this line ends content from: inc/bottom.default.html -->