diff --git a/2000/rince/.gitignore b/2000/rince/.gitignore index 8e87c9d18..8ac7f85cd 100644 --- a/2000/rince/.gitignore +++ b/2000/rince/.gitignore @@ -1 +1,2 @@ +dmy2jd rince diff --git a/2000/rince/Makefile b/2000/rince/Makefile index 25524921d..8bf31ee27 100644 --- a/2000/rince/Makefile +++ b/2000/rince/Makefile @@ -1,215 +1,330 @@ -#!/bin/make -# 2000 makefile +#!/usr/bin/env make # -# Copyright (C) Simon Cooper, Landon Curt Noll, Peter Seebach -# and Leonid A. Broukhis, 2000. -# All Rights Reserved. Permission for personal, educational or non-profit -# use is granted provided this this copyright and notice are included in its -# entirety and remains unaltered. All other uses must receive prior permission -# from the contest judges. +# IOCCC 2000 winning entry - rince -SHELL= /bin/sh -CAT= cat -RM= rm -SED= sed -TRUE= true -#CINCLUDE= -I ${HOMEBREW_PREFIX}/include/SDL2 - -# optimization +################################################################################ # -# Most compiles will safely use -O2. Some can use only -O. -# A few compilers have broken optimizers and thus you may -# not want anything. +# Regarding individual entries: +# +# IOCCC winning entry code may not work on your system. Even with standards, +# conditions and build environments change, especially when it comes to more +# extreme code such you might find in an IOCCC winner. Moreover, what was +# allowed and liked in one IOCCC contest may no longer be liked/allowed in +# later IOCCC years. +# +# Corrections on winning author and fixing typos in remarks are VERY WELCOME. +# +# GitHub pull requests are welcome: +# +# If you have a patch that might make running an entry work in modern Unix-like +# environments, please create a GitHub pull request for the IOCCC judges to +# consider. +# +# Suggestions and corrections regarding Makefiles, winning author information, +# fixing typos in remarks, and code patches are welcome via opening a GitHub +# issue or better yet, by creating a GitHub pull request for the IOCCC judges +# to consider. To form a GitHub issue or GitHub pull, please visit: +# +# https://github.com/ioccc-src/winner +# +################################################################################ + +# This work by Landon Curt Noll and Leonid A. Broukhis is licensed under: +# +# Creative Commons Attribution-ShareAlike 3.0 Unported License. +# +# See: http://creativecommons.org/licenses/by-sa/3.0/ + + +############################# +# shell used by this Makefile +############################# +# +SHELL= bash + +####################### +# common tool locations +####################### +# +include ../../var.mk + +# Set X11_LIBDIR to the directory where the X11 library resides +# +#X11_LIBDIR= /usr/X11R6/lib +#X11_LIBDIR= /usr/X11/lib +X11_LIBDIR= /opt/X11/lib + +# Set X11_INCLUDEDIR to the directory where the X11 include files reside +# +#X11_INCDIR= /usr/X11R6/include +#X11_INCDIR= /usr/X11/include +X11_INCDIR= /opt/X11/include + +# Common C compiler warnings to silence +# +#CSILENCE= +CSILENCE= -Wno-empty-body -Wno-error -Wno-implicit-function-declaration \ + -Wno-incompatible-pointer-types -Wno-parentheses -Wno-return-type \ + -Wno-unevaluated-expression + +# Common C compiler warning flags +# +#CWARN= ${CSILENCE} +#CWARN= -Wall ${CSILENCE} +#CWARN= -Wall -Wextra ${CSILENCE} +CWARN= -Wall -Wextra -pedantic ${CSILENCE} + +# Compiler standard +# +#CSTD= +#CSTD= -ansi +CSTD= -std=gnu99 + +# Compiler bit architecture +# +# Some entries require 32-bitness: +# ARCH= -m32 +# +# Some entries require 64-bitness: +# ARCH= -m64 +# +# By default we assume nothing: +# +ARCH= + +# Defines that are needed to compile +# +#CDEFINE= +CDEFINE= -DM_PI=3.14159265358979323846 + +# Include files that are needed to compile +# +#CINCLUDE= +#CINCLUDE= -include stdlib.h +#CINCLUDE= -include stdio.h +#CINCLUDE= -include stdlib.h -include stdio.h +CINCLUDE= -I ${X11_INCDIR} -I ${X11_INCDIR}/X11 +#CINCLUDE= `${SDL2_CONFIG} --cflags` + +# Optimization +# +# Most compiles will safely use -O2. Some can use only -O1 or -O. +# A few compilers have broken optimizers or this entry make break +# under those buggy optimizers and thus you may not want anything. +# Reasonable compilers will allow for -O3. # #OPT= #OPT= -O -OPT= -O2 +#OPT= -O1 +#OPT= -O2 +OPT= -O3 -# flags for ANSI compiles +# Default flags for ANSI C compilation # -# NOTE: Some ANSI compilers make use of -Xa to turn on ANSI mode, -# others such as gcc may want -ansi, others (Compaq Tru64 Unix) -# want -std1, and others may want nothing at all. -# Adjust the CFLAGS line as needed. -# -# NOTE: Some compilers cannot optimize, or optimize some entries -# incorrectly. You might want to turn on -O to see if your -# compiler can handle them. -# -# -#CFLAGS= -Xa ${OPT} -#CFLAGS= -std1 $(OPT) -CFLAGS= -ansi ${OPT} +CFLAGS= ${CSTD} ${CWARN} ${ARCH} ${CDEFINE} ${CINCLUDE} ${OPT} -NO_ANSI_CFLAGS= -#NO_ANSI_CFLAGS= +# Libraries needed to build +# +#LIBS= +#LIBS= -lm +LIBS= -lm -L ${X11_LIBDIR} -lX11 +#LIBS= `${SDL2_CONFIG} --libs` -# NOTE: On some systems, the library path does not include the location -# of the X11 libraries. You might need to use a -L/path/to/X11/lib/dir -# in order to compile with these libs. -# -X11CCFLAGS= -I/usr/X11R6/include -I/usr/X11R6/include/X11 -I/usr/include/X11 -#X11CCFLAGS= -X11LDFLAGS= -L/usr/X11R6/lib -#X11LDFLAGS= - -# Perl -# -PERL= perl -#PERL= perl5 - -# ANSI compiler -# -# Set CC to the name of your ANSI compiler. -# -# Some entries seem to need gcc. If you have gcc, set -# both CC and MAY_NEED_GCC to gcc. -# -# If you do not have gcc, set CC to the name of your ANSI compiler, and -# set MAY_NEED_GCC to either ${CC} (and hope for the best) or to just : -# to disable such programs. +# C compiler to use # CC= cc -MAY_NEED_GCC= gcc +#CC=clang +#CC=gcc -# winners that compile under ANSI C +# Compiler add-ons or replacements for clang only # -WINNERS= anderson schneiderwent primenum bellard bmeyer briddlebane dhyang \ - dmy2jd jarijyrki dlowe natori rince robison thadgavin tomx -ALT_NAMES= schneiderwent.orig briddlebane.orig thadgavin.orig -DATA_FILES= schneiderwent_files bmeyer_files jarijyrki_files - - -all: ${WINNERS} - -# Best use of flags +ifeq ($(CC),clang) # -anderson: anderson.c - ${CC} ${CFLAGS} $? -o $@ - -# Most Timely Output +CSILENCE+= -Wno-comma -Wno-float-conversion -Wno-missing-prototypes \ + -Wno-missing-variable-declarations -Wno-poison-system-directories \ + -Wno-shorten-64-to-32 -Wno-sign-conversion -Wno-strict-prototypes \ + -Wno-unreachable-code # -schneiderwent: schneiderwent.c - ${CC} ${CFLAGS} $? -o $@ - -schneiderwent_files: schneiderwent.data - -schneiderwent.orig: schneiderwent.orig.c - ${CC} ${CFLAGS} $? -o $@ - -# Best Abuse of CPP +CWARN+= -Weverything # -primenum: primenum.c - ${CC} ${CFLAGS} $? -o $@ +endif -# Most Specific Output +# Specific add-ons or replacements for gcc only # -bellard: bellard.c - ${CC} ${CFLAGS} $? -o $@ +ifeq ($(CC),gcc) +# +#CSILENCE+= +# +#CWARN+= +# +endif -# Best Utility -# -# machines operating in 64 bit mode: -# -bmeyer: bmeyer.c - ${CC} -DY= -O6 $? -o $@ -lm -# -# linux/x86, glibc 2.0, libc4/5: -# -# bmeyer: bmeyer.c -# ${CC} -DY="__setfpucw(0x127f)" -O6 $? -o $@ -lm -# -# linux/x86, glibc 2.1: -# -# bmeyer: bmeyer.c -# ${MAY_NEED_GCC} -DY='int x=0x127f; __asm__ ("fldcw %0" : : "m" (*&x))' \ -# -O6 $? -o $@ -lm -bmeyer_files: lavabus.pgm lenna.glic michael.pgm - -# Best Abuse of User +############################## +# Special flags for this entry +############################## # -briddlebane: briddlebane.c - ${CC} ${CFLAGS} $? -o $@ -lm - -briddlebane.orig: briddlebane.orig.c - ${CC} ${CFLAGS} $? -o $@ -lm - -# Best Layout +ENTRY= rince +PROG= ${ENTRY} # -dhyang: dhyang.c - ${CC} ${CFLAGS} $? -o $@ - -dmy2jd: dmy2jd.c - ${CC} ${CFLAGS} $? -o $@ - -# Best of Show +OBJ= ${PROG}.o +DATA= +TARGET= ${PROG} dmy2jd # -jarijyrki: jarijyrki.c - ${CC} ${X11CCFLAGS} ${CFLAGS} -DNeedFunctionPrototypes \ - -DU=40 -DT=98 '-Dz=(T+1)*U*U' -DQ=80 -DS=20 -DN=10 -DB=5 -DG=23 \ - -Dp=7 '-DM=((p+1)*Q)+S' '-DH=(G*S)+S+S' -DC=XK_Up -DL=XK_Down \ - -DO=XK_Left -DV=XK_Right -DR=XK_Escape -D_=XK_BackSpace \ - $? -o $@ ${X11LDFLAGS} -lX11 +ALT_OBJ= +ALT_TARGET= -jarijyrki_files: sheet1.info -# Worst Abuse of the Rules +################# +# build the entry +################# # -# NOTE: You will need to adjust this path to the place where Perl has been -# installed on your system. Running "perl -V" may help you locate -# this place. -# -# The following bit of perl may help determining the values you need: -# -# perl -MConfig -e 'print "$Config{archlibexp}/CORE\n"' -# -# -dlowe: dlowe.c - ${CC} ${NO_ANSI_CFLAGS} -DPERL_POLLUTE \ - `${PERL} -MExtUtils::Embed -e ccopts` $? -o $@ \ - `${PERL} -MExtUtils::Embed -e ldopts` - -# Best Small Program -# -natori: natori.c - ${CC} ${CFLAGS} $? -o $@ -lm - -# Astronomically Obfuscated -# -rince: rince.c - ${CC} ${X11CCFLAGS} ${CFLAGS} -DM_PI=3.14159265358979323846 \ - $? -o $@ -lm ${X11LDFLAGS} -lX11 - -# Best game -# -robison: robison.c - ${CC} ${CFLAGS} $? -o $@ - -# Most Portable Output -# -thadgavin: thadgavin.c - ${CC} ${CFLAGS} $? -o $@ -lcurses -lm - -thadgavin.orig: thadgavin.orig.c - ${CC} ${CFLAGS} $? -o $@ -lncurses -lm - -# Most Complete Program -# -tomx: tomx.c - ${CC} ${CFLAGS} $? -o $@ - -everything: ${WINNERS} ${ALT_NAMES} ${DATA_FILES} - -clean: - ${RM} -f *.o a.out core ${WINNERS} - -clobber: clean - ${RM} -f ${WINNERS} - ${RM} -f ${ALT_NAMES} - -nuke: clobber +all: data ${TARGET} @${TRUE} -install: all - ${CAT} ${WINNERS} ${ALT_NAMES} > /dev/null +.PHONY: all alt data everything clean clobber install \ + love haste waste maker easter_egg sandwich \ + supernova deep_magic magic charon pluto + +${PROG}: ${PROG}.c + ${CC} ${CFLAGS} $< -o $@ ${LIBS} + +# alternative executable +# +alt: data ${ALT_TARGET} + @${TRUE} + +# data files +# +data: ${DATA} + @${TRUE} + +# both all and alt +# +everything: all alt + + +############### +# utility rules +############### +# +clean: + ${RM} -f ${OBJ} ${ALT_OBJ} + @-if [ -f indent.c ]; then \ + echo ${RM} -f indent.c; \ + ${RM} -f indent.c; \ + fi + +clobber: clean + ${RM} -f ${TARGET} ${ALT_TARGET} + @-if [ -e sandwich ]; then \ + ${RM} -f sandwich; \ + echo 'ate sandwich'; \ + fi + +install: + @echo "Dr. Spock says that is not logical!" + @${TRUE} + +# you may be able to misunderstand the source by reading indent.c +# +indent.c: ${PROG}.c + @if which "${GINDENT}" >/dev/null 2>&1; then \ + echo ${RM} -f $@; \ + ${RM} -f $@; \ + echo "${GINDENT} < $< > $@"; \ + ${GINDENT} < $< > $@; \ + elif which "${INDENT}" >/dev/null 2>&1; then \ + echo ${RM} -f $@; \ + ${RM} -f $@; \ + echo "${INDENT} < $< > $@"; \ + ${INDENT} < $< > $@; \ + else \ + echo "no intent tool found, ident $< yourself, sorry"; \ + echo "exit 1"; \ + exit 1; \ + fi + + +################## +# 133t hacker rulz +################## +# +love: + @echo 'not war?' + @${TRUE} + +haste: + $(MAKE) waste + @${TRUE} + +waste: + @echo 'haste' + @${TRUE} + +maker: + @echo 'Participate in a maker faire' + @${TRUE} + +easter_egg: + @echo "you expected to often misunderstand this $${RANDOM} magic" + @echo "chongo '' /\\oo/\\" + @echo "Eggy" + +sandwich: easter_egg + @if [ `id -u` -eq 0 ]; then \ + echo 'Okay.'; \ + echo "$${RANDOM}`date +%s`$${RANDOM}" > $@; \ + else \ + echo 'What? Make it yourself.'; \ + exit 1; \ + fi + +# Understand the history of the Homebrew Computer Club +# as well as the West Coast Computer Faire and +# you might be confused different. :-) +# +supernova: sandwich + @-if [ -r .code_anal ]; then \ + ${RM} -f .code_anal_v6; \ + else \ + echo "planet deniers, like some members of the IAU, are so cute when they try to defend their logic"; \ + fi + @echo "A $@ helps ${MAKE} the elements that help form planets" + @${TRUE} + +deep_magic: supernova + @-if [ -r .code_anal ]; then \ + ccode_analysis --deep_magic 7889066cdbdf09b0408021754586e895be641cc9be29e7eafd3ca65359541f17 \ + --FNV1a_hash_512_bit -v2 "${PROG}" "${PROG}.c"; \ + else \ + echo "Wrong! Do it again!"; \ + sleep 2; \ + echo "Wrong! Do it again!"; \ + sleep 2; \ + echo "Wrong! Do it again!"; \ + fi + @${TRUE} + +magic: deep_magic + @-if [ -r .code_anal ]; then \ + ccode_analysis --level 20003 --mode 5717175 --FNV1a_hash_512_bit -v2 "${PROG}" "${PROG}.c"; \ + else \ + echo "If you don't eat yer meat, you can't have any pudding!"; \ + echo "How can you have any pudding if you don't eat yer meat?!"; \ + fi + @${TRUE} + +# The IOCCC resident astronomer states +# +charon: magic + @echo "$@ is a dwarf planet" + @echo "dwarf is a type of planet" + @echo "therefore IAU, $@ is a planet" + +pluto: charon + ${MAKE} charon + @echo "$@ is a dwarf planet" + @echo "dwarf is a type of planet" + @echo "therefore, $@ is a planet" + @echo "having lots of planets is good feature because supernovae can help ${MAKE} a lot of them" diff --git a/2000/rince/README.md b/2000/rince/README.md index e3428f453..0e0cd95df 100644 --- a/2000/rince/README.md +++ b/2000/rince/README.md @@ -1,333 +1,336 @@ -Astronomically Obfuscated: +# Astronomically Obfuscated: - James Bonfield - MRC Laboratory of Molcular Biology - Hills Road, - Cambridge - CB2 2QH - England +James Bonfield +MRC Laboratory of Molcular Biology +Hills Road, +Cambridge +CB2 2QH +England +# To build: -Judges' Comments: +```sh +make +``` - To build: +### To run: - make rince +```sh +./rince number number2 +``` - To run (using an X windows server): +### Try: - ./rince +```sh +make dmy2jd +./rince 0.001 `./dmy2jd 7.8 1 1610` +``` - Also try: +## Judges' comments: - make dmy2jd - ./rince 0.001 `./dmy2jd 7.8 1 1610` +This program may have you going around in circles :-) Try running it +first before reading the Selected Author's Comments below. + +The judges verified the correctness of output for recent dates +thru visual observation. + +## Author's comments: + +### How to use it + +The simplest way to run it is with no arguments. Just type: + +```sh +./rince +``` + +You will need to have access to X windows, although it doesn't require +desperately high resolution and there are no known limitations on colour +depth. + +The display will change slowly over time, although it may take 10 minutes +or more to be visible. For those that cannot wait that long the program +has a built in time machine. Indeed the program knows the speed of light, +which is used to ensure that we see the "live" pictures. Simply specify +the fraction of a day to skip forward for each screen refresh. I suggest: + +```sh +./rince 0.01 +``` + +To display the output (still guessing?) for a given date, specify two +arguments. The first argument is as before and the second argument is a +Julian day number (given as a fractional component). Eg: + +```sh +./rince 0 2441193.6 +./rince 0.01 2441193.6 +``` + +A Julian day is defined to be the number of days since January 1st in +the year -4712 (4713BC), starting at 12 noon GMT.[1] To aid conversion +from our time (GMT) to Julian day there is a supplementary program +named: dmy2jd.c. Run it with "day_float month year" as arguments. See +below for an example. + +### What it does + +This program plots the positions of the four Galilean moons of Jupiter, +as seen from earth. It doesn't correct for your location on earth, but I +assure you that the parallax is minimal! + +The moons are labelled with roman numerals from I to IV. I being the +closest to the planet and IV being the furthest. They are: + +I Io +II Europa +III Ganymede +IV Callisto +Amazingly, all it takes is a pair of binoculars to see the Galilean moons, +so the results can be experimentally checked. (Note that at present, the +best views of Jupiter are over the autumn/winter.) - This program may have you going around in circles :-) Try running it - first before reading the Selected Author's Comments below. +The positions of the moons should be correct for binoculars, but possibly +not if you have a telescope or if you are in the southern hemisphere. In +that case I suggest that to get the correct image you look at the screen +from inside the monitor whilst standing on your head. In case of +confusion, please consult the following chart (*): - The judges verified the correctness of output for recent dates - thru visual observation. + N + ^ + | + E <---+---> W + | + v + S +(*) Not to scale. -Selected Author's Comments: +### History - How to use it - ------------- +Galileo discovered the moons in January 1610. +"http://www-isds.jpl.nasa.gov/cwo/cwo_54ga/html/cd/galileo.htm" states +the following: - The simplest way to run it is with no arguments. Just type: +``` +By early 1610, Galileo had further improved his telescope by +double its power, so it now enlarged objects a thousand +times. He began looking at the stars and couldn't believe how +many more he could now see! The number seemed infinite. He was +beginning to realize the fixed stars weren't a flat distant +wall on a globe, but a three-dimensional expanse bigger than +anyone had ever thought! - ./rince +Then, on January 7, about an hour after sunset, Jupiter rose +in the east, and Galileo happened to turn his powerful scope +on its bright disk. It wasn't the first time he had looked at +Jupiter, but before it was with one of his lesser-powered +telescopes. This time, though, he noticed three small but +bright stars near the planet, two to one side and one to the +other. He wondered at how bright the small stars were and how +they were arranged in what seemed like a straight line. The +next night he decided to look at Jupiter again, and to his +surprise, the stars had moved. But not in such a way as he +would expect. If Jupiter was moving as it normally should, the +stars would be east of Jupiter. But all three were to the +west! The next night was cloudy, but on January 10, Galileo +was able to observe the planet again. One of the stars was +gone, and the other two were now on the east side. As the +stars moved around Jupiter on each succeeding night, and were +finally joined by a fourth star, it dawned on Galileo that +what he had found were moons orbiting Jupiter! Almost at once +he realized that this was proof that not all objects orbited +the Earth. Here were four bodies that were orbiting +Jupiter. One argument against the sun-centered theory was, if +the Earth orbited the sun, wouldn't the moon get left behind? +Here he could see for himself that somehow, a planet could +orbit the sun, and not leave a moon behind! +``` - You will need to have access to X windows, although it doesn't require - desperately high resolution and there are no known limitations on colour - depth. +Thus we can plot Galileo's discoveries using the following three plots: - The display will change slowly over time, although it may take 10 minutes - or more to be visible. For those that cannot wait that long the program - has a built in time machine. Indeed the program knows the speed of light, - which is used to ensure that we see the "live" pictures. Simply specify - the fraction of a day to skip forward for each screen refresh. I suggest: +```sh +./rince 0 `./dmy2jd 7.8 1 1610` +./rince 0 `./dmy2jd 8.8 1 1610` +./rince 0 `./dmy2jd 10.8 1 1610` +``` - ./rince 0.01 +However we can go one better by seeing what Galileo would have seen if it +wasn't cloudy on the 9th. Try "./rince 0 `./dmy2jd 9.85 1 1610`" to see +what he was missing out on. I wonder what he'd have made of that! - To display the output (still guessing?) for a given date, specify two - arguments. The first argument is as before and the second argument is a - Julian day number (given as a fractional component). Eg: +Galileo discovered the fourth moon a few days later. - ./rince 0 2441193.6 - ./rince 0.01 2441193.6 +I've tried typing these dates in to two Java based Jovian moon plotters, +but both I tried had problems dealing with dates earlier than 1900. More +professional software, such as the SkyMap program [3] gets these values +correct and this compares well with the above description and with this +IOCCC entry. - A Julian day is defined to be the number of days since January 1st in - the year -4712 (4713BC), starting at 12 noon GMT.[1] To aid conversion - from our time (GMT) to Julian day there is a supplementary program - named: dmy2jd.c. Run it with "day_float month year" as arguments. See - below for an example. +The year 4713BC was chosen by Joseph Justus Scaliger in the 16th Century, +so clearly this program has a long history :-) A more complete description +of the origins of Julian Days can be found at: - What it does - ------------ +http://aa.usno.navy.mil/AA/faq/docs/millennium.html - This program plots the positions of the four Galilean moons of Jupiter, - as seen from earth. It doesn't correct for your location on earth, but I - assure you that the parallax is minimal! +### Assumptions - The moons are labelled with roman numerals from I to IV. I being the - closest to the planet and IV being the furthest. They are: +1. The ASCII character set is used. - I Io - II Europa - III Ganymede - IV Callisto +2. That an enormous comet hasn't changed the course of Jupiter (or Earth!). + +3. That the date has not been specified as the gap between the Julian and Gregorian calendar. + +4. That the DISPLAY environment variable is set and the X display can opened. If this is not the case the program will crash. + +5. There is a year 2000BC problem :-) - Amazingly, all it takes is a pair of binoculars to see the Galilean moons, - so the results can be experimentally checked. (Note that at present, the - best views of Jupiter are over the autumn/winter.) +More specifically, the plots for dates that far back are too inaccurate +to be of realistic use. Comparisons against SkyMap Pro [3] show that +there is a good similarity (but not much more) up to about 500BC. - The positions of the moons should be correct for binoculars, but possibly - not if you have a telescope or if you are in the southern hemisphere. In - that case I suggest that to get the correct image you look at the screen - from inside the monitor whilst standing on your head. In case of - confusion, please consult the following chart (*): +6. The code definitely is not portable - it will produce incorrect results if run from the surface of Mars. - N - ^ - | - E <---+---> W - | - v - S +### Obfuscations - (*) Not to scale. +In addition to the normal obfuscations, I feel that the code contains +some less common tricks. Taken through the standard rounds listed in the +guidelines, the code attempts to pass these as follows: +1. Look at the original source - History - ------- + With luck, pure casual inspection should not reveal much except + that the program contains the X Windows logo (a big clue) and + contains a date. This date may give a clue to a few people that + this is an astronomical program. - Galileo discovered the moons in January 1610. - "http://www-isds.jpl.nasa.gov/cwo/cwo_54ga/html/cd/galileo.htm" states - the following: + Unfortunately I was stretched for space which meant that the + large string constant could not be split up using a "partA" + "partB" method which clearly limits the code layout. However the + space saved by using a single long string constant is more than + outweighed by ability to further obfuscate. - By early 1610, Galileo had further improved his telescope by - double its power, so it now enlarged objects a thousand - times. He began looking at the stars and couldn't believe how - many more he could now see! The number seemed infinite. He was - beginning to realize the fixed stars weren't a flat distant - wall on a globe, but a three-dimensional expanse bigger than - anyone had ever thought! +2. convert ANSI tri-graphs to ASCII - Then, on January 7, about an hour after sunset, Jupiter rose - in the east, and Galileo happened to turn his powerful scope - on its bright disk. It wasn't the first time he had looked at - Jupiter, but before it was with one of his lesser-powered - telescopes. This time, though, he noticed three small but - bright stars near the planet, two to one side and one to the - other. He wondered at how bright the small stars were and how - they were arranged in what seemed like a straight line. The - next night he decided to look at Jupiter again, and to his - surprise, the stars had moved. But not in such a way as he - would expect. If Jupiter was moving as it normally should, the - stars would be east of Jupiter. But all three were to the - west! The next night was cloudy, but on January 10, Galileo - was able to observe the planet again. One of the stars was - gone, and the other two were now on the east side. As the - stars moved around Jupiter on each succeeding night, and were - finally joined by a fourth star, it dawned on Galileo that - what he had found were moons orbiting Jupiter! Almost at once - he realized that this was proof that not all objects orbited - the Earth. Here were four bodies that were orbiting - Jupiter. One argument against the sun-centered theory was, if - the Earth orbited the sun, wouldn't the moon get left behind? - Here he could see for himself that somehow, a planet could - orbit the sun, and not leave a moon behind! + These are not used. - Thus we can plot Galileo's discoveries using the following three plots: +3. C pre-process the source ignoring #include lines +4. C pre-process the source ignoring #define and #include lines - ./rince 0 `./dmy2jd 7.8 1 1610` - ./rince 0 `./dmy2jd 8.8 1 1610` - ./rince 0 `./dmy2jd 10.8 1 1610` + This does a good job of expanding out the code, but it does not + clarify things greatly. The use of #defines has been restricted + primarily to a space-saving mechanism. - However we can go one better by seeing what Galileo would have seen if it - wasn't cloudy on the 9th. Try "./rince 0 `./dmy2jd 9.85 1 1610`" to see - what he was missing out on. I wonder what he'd have made of that! + Additionally, the use of typedefs means that the types used are + still obscured unless further replacement edits are made. - Galileo discovered the fourth moon a few days later. +5. Run it through a C beautifier. - I've tried typing these dates in to two Java based Jovian moon plotters, - but both I tried had problems dealing with dates earlier than 1900. More - professional software, such as the SkyMap program [3] gets these values - correct and this compares well with the above description and with this - IOCCC entry. + GNU indent seems to do a reasonable job, provided that the + #defines are expanded first. This doesn't lay the algorithm + particularly bare though as most of the obfuscations are not + simple code layouts. +6. Examine the algorithm. - The year 4713BC was chosen by Joseph Justus Scaliger in the 16th Century, - so clearly this program has a long history :-) A more complete description - of the origins of Julian Days can be found at: + The algorithm operates on two levels. The main visible level is + by taking a large string and breaking this down into a series of + op-codes (which I have termed J-code). These are then executed. - http://aa.usno.navy.mil/AA/faq/docs/millennium.html + To get to the real method of how it works, you need to decode + the op-code string (which deliberately contains as many ; { and + } symbols as possible), which will give you a reverse-polish + notation chunk of mathematics. + Sensible people amongst you will simply refer to the referenced + book :-) - Assumptions - ----------- +7. Lint it. - 1. The ASCII character set is used. + I no longer have lint, although I do have access to Purify. I'm + happy to say that purify does not detect any memory errors or + memory leaks. - 2. That an enormous comet hasn't changed the course of Jupiter (or Earth!). + See below for compilation warnings. - 3. That the date has not been specified as the gap between the Julian - and Gregorian calendar. +8. Compile it. - 4. That the DISPLAY environment variable is set and the X display can - opened. If this is not the case the program will crash. + I'm sorry to say that there are several warnings issued by the + compiler. - 5. There is a year 2000BC problem :-) - More specifically, the plots for dates that far back are too inaccurate - to be of realistic use. Comparisons against SkyMap Pro [3] show that - there is a good similarity (but not much more) up to about 500BC. + Firstly, the return type for X() is not specified, so it + defaults to int. Horror of all horrors - this function does not + return an integer type (it doesn't contain any specific + returns). The return value from X() is not accessed. The same + problem occurs in main - it does not return. However main never + exits unless there is a serious error. - 6. The code definitely is not portable - it will produce incorrect results - if run from the surface of Mars. + The 6th argument of XDrawText (which should be XTextItem) is + passed as a compatible structure, but without casting. This is + to reduce code space. A more elegant solution is to remove the + "struct {...} Z" completely and use "XTextItem + f={i-127+r/3*2,r%3+r/3+1,0,E}" at the start of XDrawText + block. Although this is accepted by several compilers, it is not + strict ANSI due to the non-constant initialisers. A pity. + Note that I make use of usleep(). This is a POSIX call (it is + BSD), but it supported on many systems. It may be implemented + using select() or poll() if required, or as a final solution you + may change the usleep(10000) to sleep(1). To compile on systems + which do not have usleep, but do have select, the following may + suffice as an additional compiler argument: - Obfuscations - ------------ +```sh +-Dusleep={time_t v[2]={0,10000};select(0,0,0,0,v);} +``` - In addition to the normal obfuscations, I feel that the code contains - some less common tricks. Taken through the standard rounds listed in the - guidelines, the code attempts to pass these as follows: + Gcc complains about "unreachable code at beginning of switch + statement", although removing some of this code will prevent + the algorithm from working. - 1. Look at the original source + Gcc also suggests that I should be using extra parenthesis, but + I'm taking this as good comment :-) - With luck, pure casual inspection should not reveal much except - that the program contains the X Windows logo (a big clue) and - contains a date. This date may give a clue to a few people that - this is an astronomical program. - Unfortunately I was stretched for space which meant that the - large string constant could not be split up using a "partA" - "partB" method which clearly limits the code layout. However the - space saved by using a single long string constant is more than - outweighed by ability to further obfuscate. +In addition to the above, the program has the following useful(?) +obfuscations: - 2. convert ANSI tri-graphs to ASCII +1. The algorithm requires many floating point numbers (about + 50). These are encoded as ASCII. - These are not used. +2. The J-code algorithm has op-codes designed to be space + saving. They are all one byte, but many are also considered as + white-space by the rules. This algorithm forms part of the same + string that the floating point constants are embedded + within. What does the ";" command do in J-code? - 3. C pre-process the source ignoring #include lines - 4. C pre-process the source ignoring #define and #include lines +3. The J-code language is both stack based and variable based. This + "uncleanliness" is not ideal from a computer science angle, but + when has cleanliness been considered as good in IOCCC? :-) - This does a good job of expanding out the code, but it does not - clarify things greatly. The use of #defines has been restricted - primarily to a space-saving mechanism. +4. Association of unconnected data by implied function usage. Eg + use of strlen() and sizeof() simply to return useful numerical + values, using irrelevant arguments. - Additionally, the use of typedefs means that the types used are - still obscured unless further replacement edits are made. +5. As we already have a dependency on ASCII this has been abused + further. Specifically some integer constants are specified as + ASCII and some ASCII constants are integers. This hides the true + meaning for the values. - 5. Run it through a C beautifier. +6. Red herrings: there's a couple of pieces of code whose + appearance is just there to mislead the unfirm of mind. + I've only tried to include such examples in places where at + first glance the code appears to be executed. - GNU indent seems to do a reasonable job, provided that the - #defines are expanded first. This doesn't lay the algorithm - particularly bare though as most of the obfuscations are not - simple code layouts. +### References - 6. Examine the algorithm. +[1] Astronomical algorithms (1st ed): page 59 +Jean Meeus. Published by Willmann-Bell Inc. - The algorithm operates on two levels. The main visible level is - by taking a large string and breaking this down into a series of - op-codes (which I have termed J-code). These are then executed. +[2] Astronomical algorithms (1st ed): pages 285-299. +Jean Meeus. Published by Willmann-Bell Inc. - To get to the real method of how it works, you need to decode - the op-code string (which deliberately contains as many ; { and - } symbols as possible), which will give you a reverse-polish - notation chunk of mathematics. - - Sensible people amongst you will simply refer to the referenced - book :-) - - 7. Lint it. - - I no longer have lint, although I do have access to Purify. I'm - happy to say that purify does not detect any memory errors or - memory leaks. - - See below for compilation warnings. - - 8. Compile it. - - I'm sorry to say that there are several warnings issued by the - compiler. - - Firstly, the return type for X() is not specified, so it - defaults to int. Horror of all horrors - this function does not - return an integer type (it doesn't contain any specific - returns). The return value from X() is not accessed. The same - problem occurs in main - it does not return. However main never - exits unless there is a serious error. - - The 6th argument of XDrawText (which should be XTextItem) is - passed as a compatible structure, but without casting. This is - to reduce code space. A more elegant solution is to remove the - "struct {...} Z" completely and use "XTextItem - f={i-127+r/3*2,r%3+r/3+1,0,E}" at the start of XDrawText - block. Although this is accepted by several compilers, it is not - strict ANSI due to the non-constant initialisers. A pity. - - Note that I make use of usleep(). This is a POSIX call (it is - BSD), but it supported on many systems. It may be implemented - using select() or poll() if required, or as a final solution you - may change the usleep(10000) to sleep(1). To compile on systems - which do not have usleep, but do have select, the following may - suffice as an additional compiler argument: - - -Dusleep={time_t v[2]={0,10000};select(0,0,0,0,v);} - - Gcc complains about "unreachable code at beginning of switch - statement", although removing some of this code will prevent - the algorithm from working. - - Gcc also suggests that I should be using extra parenthesis, but - I'm taking this as good comment :-) - - - In addition to the above, the program has the following useful(?) - obfuscations: - - 1. The algorithm requires many floating point numbers (about - 50). These are encoded as ASCII. - - 2. The J-code algorithm has op-codes designed to be space - saving. They are all one byte, but many are also considered as - white-space by the rules. This algorithm forms part of the same - string that the floating point constants are embedded - within. What does the ";" command do in J-code? - - 3. The J-code language is both stack based and variable based. This - "uncleanliness" is not ideal from a computer science angle, but - when has cleanliness been considered as good in IOCCC? :-) - - 4. Association of unconnected data by implied function usage. Eg - use of strlen() and sizeof() simply to return useful numerical - values, using irrelevant arguments. - - 5. As we already have a dependency on ASCII this has been abused - further. Specifically some integer constants are specified as - ASCII and some ASCII constants are integers. This hides the true - meaning for the values. - - 6. Red herrings: there's a couple of pieces of code whose - appearance is just there to mislead the unfirm of mind. - I've only tried to include such examples in places where at - first glance the code appears to be executed. - - - References - ---------- - [1] Astronomical algorithms (1st ed): page 59 - Jean Meeus. Published by Willmann-Bell Inc. - - [2] Astronomical algorithms (1st ed): pages 285-299. - Jean Meeus. Published by Willmann-Bell Inc. - - [3] Skymap Pro, by Chris Marriott - http://www.skymap.com/ +[3] Skymap Pro, by Chris Marriott +http://www.skymap.com/