forked from ioccc-src/winner
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathhow.html
568 lines (460 loc) · 18.8 KB
/
how.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
<!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:[email protected]&display=swap" rel="stylesheet">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<title>The International Obfuscated C Code Contest</title>
<link rel="icon" type="image/x-icon" href="../../favicon.ico">
<meta name="description" content="how.md for 2012/tromp">
<meta name="keywords" content="IOCCC, 2012/tromp, how.md">
</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/gen-other-html.sh -->
<!-- The content of main section of this web page came from: 2012/tromp/how.md -->
<!-- -->
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! -->
<!-- !!! Do not modify this web page, instead modify the file: 2012/tromp/how.md !!! -->
<!-- !!! Do not modify this web page, instead modify the file: 2012/tromp/how.md !!! -->
<!-- !!! Do not modify this web page, instead modify the file: 2012/tromp/how.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/index.html" class="sub-item-link">
Rules and 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="../../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/index.html">
Rules and 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="../../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>how.html for 2012/tromp</h2>
</div>
<!-- END: this line ends content from: inc/header.default.html -->
<!-- START: this line starts content from: inc/navbar.up2index.html -->
<div class="navbar">
<a class="Left" href="index.html">↑ jump to 2012/tromp/index.html ↑</a>
<a class="Right" href="https://validator.w3.org/nu/?doc=https%3A%2F%2Fwww.ioccc.org%2F2012%2Ftromp%2Fhow.html">✓</a>
</div>
<!-- END: this line ends content from: inc/navbar.up2index.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 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
<!-- BEFORE: 1st line of markdown file: 2012/tromp/how.md -->
<h3 id="notice-to-those-who-wish-for-a-greater-challenge">NOTICE to those who wish for a greater challenge:</h3>
<p><strong>If you want a greater challenge, don’t read any further</strong>:
just try to understand the program via the source.</p>
<p>If you get stuck, come back and read below for additional hints and information.</p>
<h1 id="obfuscation">Obfuscation</h1>
<p>The program implements a so called <a href="https://en.wikipedia.org/wiki/Krivine_machine">Krivine
machine</a>, enhanced with a <a href="https://en.wikipedia.org/wiki/BIOS">basic
input/output system</a> and a reference
counting <a href="https://en.wikipedia.org/wiki/Waste_collector">garbage collector</a>. The
Krivine machine is a stepwise transformer of a global state consisting of the
current term, the current environment (a list of closures), and a stack of
continuations (see the 3rd reference for details).</p>
<p>The term space holds <a href="https://en.wikipedia.org/wiki/Lambda_calculus">lambda
calculus</a> terms in the following
format. 0 denotes some form of I/O; the only four occurrences are at:</p>
<pre><code> C=13: recognizes end of a byte
C=20: recognize output of 0 bit
C=21: recognize output of 1 bit
C=end: input list, expanded lazily</code></pre>
<p><code>1</code> denotes a variable, with the next entry its <a href="https://en.wikipedia.org/wiki/De_Bruijn_index">de Bruijn
index</a>.</p>
<p><code>2</code> denotes application with the next entry the size of the term being applied.</p>
<p><code>3</code> denotes lambda abstraction.</p>
<p>A closure consists of the following items:</p>
<ol start="0" type="1">
<li>pointer to the next closure (as part of an environment), or next record on
free list.</li>
<li>reference count.</li>
<li>pointer to environment.</li>
<li>lambda term (index in term space).</li>
</ol>
<p>Here’s what each variable does:</p>
<pre><code> L Lambda term space
m mode: 0 for bits and 7 for bytes
b bits remaining unread in I, -1 on EOF
D Desirable temporary
c continuation context
a active environment pointer
C Current term index
U Ultimate term pointer
u utility entry
B Born to be free-list of closures
I Input character
O Output character
e entry of current term</code></pre>
<p>Here’s what each of the 6 auxiliary functions do:</p>
<pre><code> s variable lookup in active environment with de Bruijn index u
S gets one bit of input, setting b to -1 on EOF or to remaining number of bits in current byte
k copy fragment from string literal holding lambda terms xor 46 into current end of term space
x expand input, adding 11 (resp. 99) entries to term space for bit (resp. byte) mode
p parses BLC-encoded lambda term using S(), stores results in term space and returns length
d decrease reference counter, add record to free list on reaching zero</code></pre>
<hr style="width:10%;text-align:left;margin-left:0">
<p>Jump to: <a href="#">top</a></p>
<!--
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: 2012/tromp/how.md -->
<!-- END: this line ends content for HTML phase 21 by: bin/pandoc-wrapper.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.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">
<div id="copyright"><h3>Copyright © 1984-2024 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%2F2012%2Ftromp%2Fhow.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>
</p>
</div>
</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 -->