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<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>1992/imc - Best Output</h2>
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  <a class="Left" href="../gson/index.html">&larr; gson</a>
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<h2 id="author"><a name="author"></a>Author:</h2>
<ul>
<li>Name: <a href="../../authors.html#Ian_Collier">Ian Collier</a><br>
Location: <a href="../../location.html#GB">GB</a> - <em>United Kingdom of Great Britain and Northern Ireland</em> (<em>United Kingdom</em>)</li>
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<h2 id="to-build">To build:</h2>
<pre class="&lt;!---sh--&gt;"><code>    make all</code></pre>
<h2 id="to-use">To use:</h2>
<pre class="&lt;!---sh--&gt;"><code>    # text mode
    ./imc -text

    ./imc</code></pre>
<h2 id="try">Try:</h2>
<p>To see a number of options and configurations:</p>
<pre class="&lt;!---sh--&gt;"><code>    ./try.sh</code></pre>
<h2 id="judges-remarks">Judges’ remarks:</h2>
<p>The program is more interesting to run on workstations that can make use of a
Sun raster file. Others can make use of the -text flag for character oriented
output.</p>
<p>Of course, the source (layout) is self-documenting! :-)</p>
<p>NOTE: The original winning source assumed that <code>exit(3)</code> returned a value which
cause problems for some systems where <code>exit(3)</code> returns a void. The file
<a href="imc.c">imc.c</a> has been modified to avoid this problem. The original file also
declared argc to be a <code>long</code> which was fixed.</p>
<h2 id="authors-remarks">Author’s remarks:</h2>
<h3 id="portability">Portability</h3>
<p>This program depends upon the ASCII character set, and makes certain assumptions
about the architecture. It naughtily declares the first argument to <code>main()</code> as
a <code>long</code>, and passes a pointer to <code>long</code> instead of <code>char</code> to <code>fwrite(3)</code>,
giving a length value of 32 bytes for an array of 8 <code>long</code>s. I guess that makes
this program OK on most flavours of unix, but not on PCs.</p>
<h3 id="about-the-program">About the program</h3>
<p>This program has several parameters; each of them has a default, so the
program runs happily without any parameters. If you supply an incorrect
parameter, an obfuscated error message results! :-) Should you want to
run the program without knowing what it does, then supplying the single
letter <code>t</code> as a parameter is a good move. Otherwise, direct the output
into a file. The resulting file is most useful on SunOS, where the
<code>file(1)</code> command will tell you what to do with it. For best results with
the <code>t</code> option, you may want to change the definition of the <code>I</code> macro :-)
Details appear later, though the formatting of the code is a large clue.</p>
<p>All the code in this program appears between the <code>;</code> and <code>)</code> in
<code>for(;;)</code>. That isn’t because I want to win the best one-liner, but
merely because it makes the code so much more impenetrable :-) In fact
running a pretty printer on the code hardly improves it at all. This
program has the obligatory macros with unmatched parentheses, and the
cleverly arranged macro names and parameters to spell out <code>"Ian Colliers Obfuscated C Code"</code>. If you expand macros, bear in mind that the more
complex ones are best left as macros, because they have well-defined and
nontrivial (IMHO) functions. These macros help to give the program’s
parameter format its flexibility. The parameters are sorted out in a
unique way (based on an idea by Pete Bevin) which hides very effectively
their identities (and I think that using a variable called <code>_</code> adds a nice
touch to the illegibility of the code). In this section of the code, the
data types of the numbers checked against is varied, and just because
you see a <code>,</code> doesn’t mean it has anything to do with commas! So I hope
you will agree that this program is more than a little obfuscated…</p>
<p>This is a Mandelbrot/Julia drawer. Normally it produces a monochrome
Sun-format raster file. The version of <code>xloadimage</code> we have is able to
view such files, and so is Sun’s <code>screenload</code> command. [Note: the header
contains eight 4-byte integers, the byte order in which depends upon the
machine. On Sun workstations they are stored MSB first].</p>
<p>The program may be asked to produce text output instead of a raster
file. Then the characters defined in the <code>I</code> macro will be used to create
up to 16 different shades of grey. Quite a respectable picture can be
gained by printing a <code>130x110</code> output on a <a href="https://en.wikipedia.org/wiki/Dot_matrix_printing">dot matrix 132 column
printer</a> with the linefeed
set to 7 points. Text output also gives a good picture when used in an X window
with small characters having a square aspect ratio.</p>
<p>The options accepted by the program follow. Each option is a single letter; it
may be preceded with a minus sign (or any character in <code>[!-/]</code>) and may be
followed by other letters, so for example:</p>
<ul>
<li>m</li>
<li>-m</li>
<li>mask</li>
<li>*mail</li>
</ul>
<p>all mean the same thing. Most options may be followed by one or two
numbers. These numbers may be separated from each other and from the
option by a space, or may be joined to each other with a comma, or may
be appended to the single-letter option, so</p>
<ul>
<li>-s100,200</li>
<li>size 100,200</li>
<li>-size123 100 200</li>
<li>s100 200</li>
</ul>
<p>all mean the same (note that in <code>-size123</code> all characters following the
initial <code>s</code> are ignored). Numbers need not be specified, as each has a
default value. In all cases except for <code>j</code>, <code>t</code>, and <code>s</code> whenever it
appears before <code>t</code>, specifying an option without numbers has no effect.
(specifying <code>-s -t</code> has the effect of producing text with the default
raster size; not a good idea!).</p>
<h3 id="options">Options</h3>
<p>The options of this program are:</p>
<pre><code>    -centre x y  (float x,y) Centre the picture at x+iy in the complex
                             plane (default x=0 y=0)


    -factor f    (float f)   Use f pixels per unit of the plane (default
                             f=x/4 where x is the width)


    -julia  x y  (float x,y) Draw a julia set. Use x+iy as the constant
                             to add after squaring (default x=0 y=0)

    -limit  l    (int l)     Use l iterations maximum (default l=128)

    -mask   m    (int m)     Use m as a mask in deciding the colour of each
                             pixel (see below) (default m=1)

    -size   x y  (int x,y)   Produce an x-by-y output (default for raster
                             x=768 y=768; default for text x=63 y=23)

    -text                    Produce text instead of raster.</code></pre>
<p>The colour of each point is determined by taking the bitwise AND of the
number of iterations and the mask. For a raster, the point is black
(1-bit) if the result is zero, white otherwise. For text, the result of
the operation determines the greyness of the character produced, with a
blank for zero going up to a star for the maximum value. For a
four-colour picture, for example, use a mask with two bits set (e.g. 3),
and for a 16-colour picture use a mask with four bits set (e.g. 15). For
a picture with coarse detail, use a mask which ends with several zero
bits (e.g. 8).</p>
<p>While the program is creating your picture, it displays dots on the
standard error to indicate its progress (one dot per pixel line).</p>
<h3 id="example-pictures-to-try">Example pictures to try</h3>
<p>Here are a couple of good pictures to draw:</p>
<pre class="&lt;!---sh--&gt;"><code>    ./imc -s 512,512 -f 600000 -l 512 -m 16 -c.00805,.74274 &gt; screen1.ras
    ./imc -s512,512 -j-.523,-.535 &gt; screen2.ras</code></pre>
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<h1 id="inventory-for-1992imc"><a name="inventory"></a>Inventory for 1992/imc</h1>
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<h2 id="primary-files">Primary files</h2>
<ul>
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1992/imc/imc.c">imc.c</a> - entry source</li>
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1992/imc/Makefile">Makefile</a> - entry Makefile</li>
<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1992/imc/imc.orig.c">imc.orig.c</a> - original source</li>
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