diff --git a/2000/bmeyer/Makefile b/2000/bmeyer/Makefile index 25524921d..d91873185 100644 --- a/2000/bmeyer/Makefile +++ b/2000/bmeyer/Makefile @@ -1,215 +1,329 @@ -#!/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 - bmeyer -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-format -Wno-parentheses -Wno-string-plus-int + +# 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= -DY= + +# 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 ${X11_INCDIR} +#CINCLUDE= `${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= -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-disabled-macro-expansion -Wno-float-conversion \ + -Wno-format-nonliteral -Wno-missing-prototypes \ + -Wno-missing-variable-declarations -Wno-poison-system-directories \ + -Wno-shadow -Wno-shorten-64-to-32 -Wno-sign-conversion \ + -Wno-strict-prototypes # -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= bmeyer +PROG= ${ENTRY} # -dhyang: dhyang.c - ${CC} ${CFLAGS} $? -o $@ - -dmy2jd: dmy2jd.c - ${CC} ${CFLAGS} $? -o $@ - -# Best of Show +OBJ= ${PROG}.o +DATA= lavabus.pgm lenna.glic michael.pgm +TARGET= ${PROG} # -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/bmeyer/README.md b/2000/bmeyer/README.md index 25cbee753..d24fad64a 100644 --- a/2000/bmeyer/README.md +++ b/2000/bmeyer/README.md @@ -1,351 +1,398 @@ -Best Utility: +# Best Utility: - Bernd Meyer - Monash University, Melbourne, Australia - 1/832 Blackburn Rd - Clayton, VIC 3168 - Australia +Bernd Meyer +Monash University, Melbourne, Australia +1/832 Blackburn Rd +Clayton, VIC 3168 +Australia - http://byron.csse.monash.edu.au/ +http://byron.csse.monash.edu.au/ +# To build: -Judges' Comments: +```sh +make +``` - To build: +### To run: - make bmeyer +```sh +./prog +``` - Compile with the maximum possible optimization on your system. - If your system has 80-bit internal representation of floating - point values (x86, some Motorola processors) and you want the - compressed format to be portable across platforms, you need - to set your FPU to use 64 bit mode. See the extra build lines - in the Makefile, and read the author's comments below. +### Try: - If you cannot work out hwo to get into 64 bit mode, you can - try using -ffloat-store if you compile with GCC (this may have - a performance penalty). The resulting binary will have a good - chance to produce portable files, but due to the resulting - double-rounding (first internally to 80 bit, then to 64 bit - on writing the value to memory), there is a small but very real - chance any given file produced might not be portable. +In a video window (white text on black background): - To run: +```sh +./bmeyer < michael.pgm > michael.glic +``` - In a video window (white text on black background): +Compare the michael.pgm to the screen output. - ./bmeyer < michael.pgm > michael.glic +To test that you are compressing and decompressing the same way the +author was, try: - Compare the michael.pgm to the screen output. +```sh +./bmeyer < lenna.glic +``` - To test that you are compressing and decompressing the same way the - author was, try +Also try in a reverse video window: - ./bmeyer < lenna.glic +```sh +./bmeyer < michael.pgm 2>/dev/null | ./bmeyer > new.pgm +``` - Also try in a reverse video window: +Compare the michael.pgm to the screen output. Compare the new.pgm file +to the michael.pgm file. - ./bmeyer < michael.pgm 2>/dev/null | ./bmeyer > new.pgm +Create a large reverse video xterm, say 200 columns wide and try: - Compare the michael.pgm to the screen output. Compare the new.pgm file - to the michael.pgm file. +```sh +./bmeyer 200 < lavabus.pgm > lavabus.glic +``` - Create a large reverse video xterm, say 200 columns wide and try: - - ./bmeyer 200 < lavabus.pgm > lavabus.glic - - Produce an even smaller output: +Produce an even smaller output: - ./bmeyer -2 200 < lavabus.pgm > lavabus.glic2 +```sh +./bmeyer -2 200 < lavabus.pgm > lavabus.glic2 +``` - Decompress that smaller glic-file: +Decompress that smaller glic-file: - ./bmeyer -2 200 < lavabus.glic2 > new.pgm +```sh +./bmeyer -2 200 < lavabus.glic2 > new.pgm +``` - Compare the new.pgm file to the lavabus.pgm file by viewing - them. +Compare the new.pgm file to the lavabus.pgm file by viewing them. - Don't even think of supplying different compression factors (the - dashed argument) for compression and decompression! You've been warned. +## Judges' comments: +Don't even think of supplying different compression factors (the +dashed argument) for compression and decompression! You've been warned. -Selected Author's Comments: +The author recommended on linux/x86, glibc 2.0, libc4/5: - GLICBAWLS +```make +bmeyer: bmeyer.c + CC -DY="__setfpucw(0x127f)" -O6 $? -o $@ -lm +``` - A) Function - =========== +However many compilers use -O3 as the maximum level for -O optimization. - "GLICBAWLS" stands for: +And on linux/x86, glibc 2.1: - "Grey Level Image Compression By Adaptive Weighted Least Squares". +```make +bmeyer: bmeyer.c + gcc -DY='int x=0x127f; __asm__ ("fldcw %0" : : "m" (*&x))' $? -o $@ -lm +``` - And that's exactly what this program does --- feed it a .PGM file - (either raw [i.e. P5] or ascii [i.e. P2]) on stdin, and it will - output a compressed version to stdout. Feed it a compressed file - on stdin, and it will decompress it to stdout --- as either raw or - ascii .PGM, depending on what format it was compressed from. For - example: +Compile with the maximum possible optimization on your system. +If your system has 80-bit internal representation of floating +point values (x86, some Motorola processors) and you want the +compressed format to be portable across platforms, you need +to set your FPU to use 64 bit mode. See the extra build lines +in the Makefile, and read the author's comments below. - ./bmeyer < michael.pgm > michael.glic +If you cannot work out how to get into 64 bit mode, you can +try using -ffloat-store if you compile with GCC (this may have +a performance penalty). The resulting binary will have a good +chance to produce portable files, but due to the resulting +double-rounding (first internally to 80 bit, then to 64 bit +on writing the value to memory), there is a small but very real +chance any given file produced might not be portable. - and then +The makefile defaults to -O3 and no `asm()` call. - ./bmeyer < michael.glic > michael.decoded.pgm +## Author's comments: - As it turns out, glicbawls compresses greyscale images (or, more - precisely, "natural" greyscale images) better than any other - program I am aware of (with the exception of the not-yet-published - program developed for my PhD thesis). Of course, this might take - some time, so a progress indicator is provided. To make things - more interesting, instead of a boring bar or percentage display, - an ASCII rendition of the image being compressed/decompressed is - output to stderr (assuming white text on black background). If you - have trouble recognizing the image, try squinting at it ;-). +GLICBAWLS - If you still have trouble, simply use a terminal or xterm with - more than 80 columns, and tell glicbawls about it by giving the - number of columns as an argument. For example +A) Function +=========== - ./bmeyer 260 lavabus.glic +"GLICBAWLS" stands for: - will allow glicbawls to use up to 260 columns, which makes things - much more recognizable. + "Grey Level Image Compression By Adaptive Weighted Least Squares". - Still running out of space? Need to compress those images just a - tad more? And maybe you can handle some loss due to the - compression? If so, you can use glicbawls' "near lossless" - compression mode. In that mode, the decoded pixel values are - allowed to differ from tbe originals, but there is an upper limit - on the magnitude of the difference. For example, if a maximum - error of 2 is allowed, an original pixel value of 37 could be - decoded as 35,36,37, 38 or 39. In order to use this mode, simply - give the maximum allowed error as an argument, with a dash ('-') - before it. For example +And that's exactly what this program does --- feed it a .PGM file +(either raw [i.e. P5] or ascii [i.e. P2]) on stdin, and it will +output a compressed version to stdout. Feed it a compressed file +on stdin, and it will decompress it to stdout --- as either raw or +ascii .PGM, depending on what format it was compressed from. For +example: - ./bmeyer -2 < graph.pgm > graph.2.glic +```sh +./bmeyer < michael.pgm > michael.glic +``` - will compress in a way that allows decompression with a maximum - error of two. You can combine both types of arguments, i.e. +and then - ./bmeyer -3 180 < graph.pgm >graph.3.glic +```sh +./bmeyer < michael.glic > michael.decoded.pgm +``` - will compress with a maximum error of 3, using a 180 column - terminal for the progress display, and +As it turns out, glicbawls compresses greyscale images (or, more +precisely, "natural" greyscale images) better than any other +program I am aware of (with the exception of the not-yet-published +program developed for my PhD thesis). Of course, this might take +some time, so a progress indicator is provided. To make things +more interesting, instead of a boring bar or percentage display, +an ASCII rendition of the image being compressed/decompressed is +output to stderr (assuming white text on black background). If you +have trouble recognizing the image, try squinting at it ;-). - ./bmeyer -3 180 < graph.3.glic > graph.3maxerr.pgm +If you still have trouble, simply use a terminal or xterm with +more than 80 columns, and tell glicbawls about it by giving the +number of columns as an argument. For example - will decompress the result on such a terminal. +```sh +./bmeyer 260 lavabus.glic +``` - But wait, there is more --- you can also feed glicbawls .PPM files - (i.e. colour images), raw or ascii, your choice. Glicbawls will - compress and decompress them just fine. However, it only does - "reasonably well" on them; It beats PNG easily, but there are - certainly programs out there that can compress colour images - considerably better. And don't even *think* about using it for - so-called "artistic" images (i.e. anything that wasn't scanned - from a photo or camera).... +will allow glicbawls to use up to 260 columns, which makes things +much more recognizable. - ***************************************************************** - * * - * WARNING WARNING WARNING WARNING WARNING WARNING WARNING * - * * - * * - * Glicball is rather CPU and FPU intensive. Don't * - * run it on anything slow. Things start to be * - * usable around 300+MHz, with 600+ being highly * - * desirable. * - * * - ***************************************************************** +Still running out of space? Need to compress those images just a +tad more? And maybe you can handle some loss due to the +compression? If so, you can use glicbawls' "near lossless" +compression mode. In that mode, the decoded pixel values are +allowed to differ from tbe originals, but there is an upper limit +on the magnitude of the difference. For example, if a maximum +error of 2 is allowed, an original pixel value of 37 could be +decoded as 35,36,37, 38 or 39. In order to use this mode, simply +give the maximum allowed error as an argument, with a dash ('-') +before it. For example + +```sh +./bmeyer -2 < graph.pgm > graph.2.glic +``` + +will compress in a way that allows decompression with a maximum +error of two. You can combine both types of arguments, i.e. + +```sh +./bmeyer -3 180 < graph.pgm >graph.3.glic +``` + +will compress with a maximum error of 3, using a 180 column +terminal for the progress display, and + +```sh +./bmeyer -3 180 < graph.3.glic > graph.3maxerr.pgm +``` + +will decompress the result on such a terminal. + +But wait, there is more --- you can also feed glicbawls .PPM files +(i.e. colour images), raw or ascii, your choice. Glicbawls will +compress and decompress them just fine. However, it only does +"reasonably well" on them; It beats PNG easily, but there are +certainly programs out there that can compress colour images +considerably better. And don't even *think* about using it for +so-called "artistic" images (i.e. anything that wasn't scanned +from a photo or camera).... + +***************************************************************** +* * +* WARNING WARNING WARNING WARNING WARNING WARNING WARNING * +* * +* * +* Glicball is rather CPU and FPU intensive. Don't * +* run it on anything slow. Things start to be * +* usable around 300+MHz, with 600+ being highly * +* desirable. * +* * +***************************************************************** - B) Compile Instructions - ======================= +B) Compile Instructions +======================= - Unlike most compression program, glicbawls makes heavy use of - floating point maths --- and not all FPUs are created equal. Most - importantly, the x86 and 68k FPUs use 80 bit floating point - formats internally, while most other processors use IEEE 64 bit - formats by default. If not taken care of, this means that a - glicbawls file compressed on one CPU cannot generally be - decompressed on another. +Unlike most compression program, glicbawls makes heavy use of +floating point maths --- and not all FPUs are created equal. Most +importantly, the x86 and 68k FPUs use 80 bit floating point +formats internally, while most other processors use IEEE 64 bit +formats by default. If not taken care of, this means that a +glicbawls file compressed on one CPU cannot generally be +decompressed on another. - Fortunately, just about all current FPUs can be put into IEEE 64 - bit mode (or at least something close enough for - glicbawls). Unfortunately, there is no standard way of doing - so. For this reason, the build file contains *three* compile - lines; One for machines that already use 64 bit mode by default - (most RISC processors), one for linux/x86 machines using libc4, - libc5 or glibc2.0, and one for linux/x86 machines using glibc2.1 - (glibc2.1 no longer exports the __setfpucw function, necessitating - the use of gcc inline assembly. *Grumble*). +Fortunately, just about all current FPUs can be put into IEEE 64 +bit mode (or at least something close enough for +glicbawls). Unfortunately, there is no standard way of doing +so. For this reason, the build file contains *three* compile +lines; One for machines that already use 64 bit mode by default +(most RISC processors), one for linux/x86 machines using libc4, +libc5 or glibc2.0, and one for linux/x86 machines using glibc2.1 +(glibc2.1 no longer exports the __setfpucw function, necessitating +the use of gcc inline assembly. *Grumble*). - So, if you are building on a machine that does not, by default, - use IEEE 64 bit floating point doubles, you'll have to define Y to - be a command that switches it into that mode. If you fail to do - so, your glicbawls executable will still be able to decompress its - own compressed files, but you may be unable to exchange files with - glicbawls on other machines. +So, if you are building on a machine that does not, by default, +use IEEE 64 bit floating point doubles, you'll have to define Y to +be a command that switches it into that mode. If you fail to do +so, your glicbawls executable will still be able to decompress its +own compressed files, but you may be unable to exchange files with +glicbawls on other machines. - C) Obfuscation - ============== +C) Obfuscation +============== - Most of the obfuscation of this program was driven by the - desperate struggle to fit all of glicbawls' features into code - that fits the IOCCC's size limits. All identifiers names are - single-character, which was only possible by ruthless exploitation - of scope. There is a function M() that handles nearly all input - from stdin, handles all output to stdout, and also recursively - calculates one of the mathematical expressions needed for error - modelling. There is a function that calculates (A^(-1)*b)*x with A - a matrix and b and x being vectors, and does so in a very - efficient way --- but one would be hard pressed to find it. There - is an arithmetic coder that is even less recognizable. A lot of - loop variables don't get initialized, but instead the code is - arranged in such a way that they just happen to have the right - value when control flow reaches the loops. Lots of functions use - the same two global scratch variables. Variables change their - meaning all the time, and the differences between compressing and - decompressing are handled in rather subtle ways all over the - program. The string that holds the ascii values for displaying the - progress image doubles as a description on how to find a pixel's - causal neighbours. And then there are a few #define's that really - are just in there to save a few characters, but as an added - "benefit" make the source ever more unreadable. +Most of the obfuscation of this program was driven by the +desperate struggle to fit all of glicbawls' features into code +that fits the IOCCC's size limits. All identifiers names are +single-character, which was only possible by ruthless exploitation +of scope. There is a function M() that handles nearly all input +from stdin, handles all output to stdout, and also recursively +calculates one of the mathematical expressions needed for error +modelling. There is a function that calculates (A^(-1)*b)*x with A +a matrix and b and x being vectors, and does so in a very +efficient way --- but one would be hard pressed to find it. There +is an arithmetic coder that is even less recognizable. A lot of +loop variables don't get initialized, but instead the code is +arranged in such a way that they just happen to have the right +value when control flow reaches the loops. Lots of functions use +the same two global scratch variables. Variables change their +meaning all the time, and the differences between compressing and +decompressing are handled in rather subtle ways all over the +program. The string that holds the ascii values for displaying the +progress image doubles as a description on how to find a pixel's +causal neighbours. And then there are a few #define's that really +are just in there to save a few characters, but as an added +"benefit" make the source ever more unreadable. - In short --- running it through the preprocessor and the - pretty-printer will give you something that looks slightly less - like line noise and slightly more like a C program, but unless you - are a true wizard, it is unlikely to gain you any insights into - what is actually going on....[0] +In short --- running it through the preprocessor and the +pretty-printer will give you something that looks slightly less +like line noise and slightly more like a C program, but unless you +are a true wizard, it is unlikely to gain you any insights into +what is actually going on....[0] - D) Bugs, Assumptions and TODOs - ============================== +D) Bugs, Assumptions and TODOs +============================== - Glicbawls assumes that characters are 8 bit wide, and that the - character set used is ASCII. If one of these isn't true, all hell - will break loose. +Glicbawls assumes that characters are 8 bit wide, and that the +character set used is ASCII. If one of these isn't true, all hell +will break loose. - The .PGM headers are not checked very thoroughly --- glicbawls - will happily try to encode lots of files that it shouldn't - touch. The old adage of "garbage in, garbage out" holds in that - case. Furthermore, even if glicbawls detects an incorrect input, - it fails to provide a meaningful error message, and instead - simply aborts. +The .PGM headers are not checked very thoroughly --- glicbawls +will happily try to encode lots of files that it shouldn't +touch. The old adage of "garbage in, garbage out" holds in that +case. Furthermore, even if glicbawls detects an incorrect input, +it fails to provide a meaningful error message, and instead +simply aborts. - When decompressing a near-losslessy encoded image, the maximum - allowed error is required as a command line parameter. This should - really be saved in the compressed file! +When decompressing a near-losslessy encoded image, the maximum +allowed error is required as a command line parameter. This should +really be saved in the compressed file! - Glicbawls relies on the decimal representation of all integers - having less than 255 digits. While ANSI C does not guarantee this, - it seems rather unlikely that anyone in the foreseeable future - would use images with 10^255 rows, columns or different levels of - grey. Also, it is assumed that any integer used can be cast to a - double and back without loss of precision. This limits the number - of rows, columns and grey levels to 9 quintillion, which should - also be sufficient for the next few years. +Glicbawls relies on the decimal representation of all integers +having less than 255 digits. While ANSI C does not guarantee this, +it seems rather unlikely that anyone in the foreseeable future +would use images with 10^255 rows, columns or different levels of +grey. Also, it is assumed that any integer used can be cast to a +double and back without loss of precision. This limits the number +of rows, columns and grey levels to 9 quintillion, which should +also be sufficient for the next few years. - There is a theoretical chance that you might get a division by - zero error. You have a MUCH better chance of getting hit by - lightning the very second you realize that you just won a few - million in a lottery. But if it happens to you, don't say I - didn't warn you! Instead, go out and buy a lightning rod and a - lottery ticket ;-) +There is a theoretical chance that you might get a division by +zero error. You have a MUCH better chance of getting hit by +lightning the very second you realize that you just won a few +million in a lottery. But if it happens to you, don't say I +didn't warn you! Instead, go out and buy a lightning rod and a +lottery ticket ;-) - At one point, a pointer to int is used as the target of a "%1[#]" - conversion in a scanf, which makes gcc rather unhappy, but - shouldn't really cause anyone any trouble. The same goes for a - couple of assignments which are used as truth values. +At one point, a pointer to int is used as the target of a "%1[#]" +conversion in a scanf, which makes gcc rather unhappy, but +shouldn't really cause anyone any trouble. The same goes for a +couple of assignments which are used as truth values. - E) Algorithm - ============ +E) Algorithm +============ - An exhaustive explanation of the algorithm used would go beyond - the scope of an info file, and would also be quite difficult in - pure ASCII, so the following is just a rough outline, and contains - some compression-speak... +An exhaustive explanation of the algorithm used would go beyond +the scope of an info file, and would also be quite difficult in +pure ASCII, so the following is just a rough outline, and contains +some compression-speak... - The image is handled in scanline ordering. For each pixel, an - expected value is calculated by creating a least squares predictor - of order 12 based on all of the previously encoded/decoded - pixels. However, the contribution of each pixel is weighted - according to its Manhattan-distance from the current pixel, - D. That weight used is pow(0.8,D). [1][2][3] +The image is handled in scanline ordering. For each pixel, an +expected value is calculated by creating a least squares predictor +of order 12 based on all of the previously encoded/decoded +pixels. However, the contribution of each pixel is weighted +according to its Manhattan-distance from the current pixel, +D. That weight used is pow(0.8,D). [1][2][3] - In a similar way, the prediction *errors* for all previous pixels - are combined --- a weighted average (with weight pow(0.7,D)) of - the squares of all previous prediction errors is taken, and the - square root of the (appropriately scaled) result is called sigma. +In a similar way, the prediction *errors* for all previous pixels +are combined --- a weighted average (with weight pow(0.7,D)) of +the squares of all previous prediction errors is taken, and the +square root of the (appropriately scaled) result is called sigma. - The predicted value and sigma are then used as the parameters of a - Student or t-distribution (which is similar to a normal - distribution, but has more weight in the tails), providing a - probability distribution for the current pixel. +The predicted value and sigma are then used as the parameters of a +Student or t-distribution (which is similar to a normal +distribution, but has more weight in the tails), providing a +probability distribution for the current pixel. - Next, the possible interval of values for the current pixel is - halved, and through integration of the probability distribution, a - probability is calculated for the pixel value being in the lower - half. During encoding, the actual value is examined, and the - result encoded using an arithmetic coder. During decoding, the - arithmetic decoder provides the information which half the actual - value is in. In both cases, the interval borders are adjusted - accordingly, the arithmetic coder/decoder updated, and the - interval halving repeated until the precise value has been - en/decoded[4]. +Next, the possible interval of values for the current pixel is +halved, and through integration of the probability distribution, a +probability is calculated for the pixel value being in the lower +half. During encoding, the actual value is examined, and the +result encoded using an arithmetic coder. During decoding, the +arithmetic decoder provides the information which half the actual +value is in. In both cases, the interval borders are adjusted +accordingly, the arithmetic coder/decoder updated, and the +interval halving repeated until the precise value has been +en/decoded[4]. - [0] Yes, this could be seen as a challenge.... - [1] Actually, the weight is pow(0.8,D)/s, where s is the sigma - used for en/decoding the particular previous pixel. Dividing - by s is a rather arbitrary action justified only by the - improvement in results. Mathematically, I can only justify - dividing by s^2, or not dividing at all.... - [2] Obviously, these least squares predictors are not calculated - from scratch for each pixel. Some clever reuse of earlier - results allows O(1) calculation, rather than the - O(previous_rows*columns) this description would suggest. - [3] As anyone who has ever tried local least squares knows from - bitter experience, there is a lot of numerical instability - associated with them. So glicbawls adds a bias towards an - averaging predictor to the equation system the least squares - predictor is calculated from. The weight that is given to - this bias is constantly adjusted throughout coding/decoding, - thus justifying the 'a' in "glicbawls". - [4] In the case of near-lossless coding, the interval is not - necessarily *halved*, but rather split at a convenient point - (the split points are chosen in such a way as to minimise the - expected number of bits needed for coding). Also, the - iteration ends as soon as the interval is small enough to - guarantee decoding within the requested maximum error. +[0] Yes, this could be seen as a challenge.... +[1] Actually, the weight is pow(0.8,D)/s, where s is the sigma + used for en/decoding the particular previous pixel. Dividing + by s is a rather arbitrary action justified only by the + improvement in results. Mathematically, I can only justify + dividing by s^2, or not dividing at all.... +[2] Obviously, these least squares predictors are not calculated + from scratch for each pixel. Some clever reuse of earlier + results allows O(1) calculation, rather than the + O(previous_rows*columns) this description would suggest. +[3] As anyone who has ever tried local least squares knows from + bitter experience, there is a lot of numerical instability + associated with them. So glicbawls adds a bias towards an + averaging predictor to the equation system the least squares + predictor is calculated from. The weight that is given to + this bias is constantly adjusted throughout coding/decoding, + thus justifying the 'a' in "glicbawls". +[4] In the case of near-lossless coding, the interval is not + necessarily *halved*, but rather split at a convenient point + (the split points are chosen in such a way as to minimise the + expected number of bits needed for coding). Also, the + iteration ends as soon as the interval is small enough to + guarantee decoding within the requested maximum error. - #################################################################### +#################################################################### - Photo Credit: +Photo Credit: - Lavabus was taken by the judge, Landon Curt Noll. Michael was - provided by the author. Lenna is a 1972 Playboy centerfold. + Lavabus was taken by the judge, Landon Curt Noll. Michael was + provided by the author. Lenna is a 1972 Playboy centerfold. - michael.pgm + michael.pgm - The author's Godchild and nephew. + The author's Godchild and nephew. - lavabus.pgm + lavabus.pgm - A bus that was trapped by lava from Kilauea volcano in - Hawaii, USA. Nobody was in the bus at the time, BTW. - Photo date: 1981. + A bus that was trapped by lava from Kilauea volcano in + Hawaii, USA. Nobody was in the bus at the time, BTW. + Photo date: 1981. - lenna.glic + lenna.glic - A November 1972 Playboy centerfold was scanned in long ago and - has been used for image compression research since then. Playboy - originally threatened to prosecute unauthorized use, but - eventually granted that, having been in use for image compression - testing for so long, it was now a useful benchmark. (Note: This - picture doesn't show very much.) + A November 1972 Playboy centerfold was scanned in long ago and + has been used for image compression research since then. Playboy + originally threatened to prosecute unauthorized use, but + eventually granted that, having been in use for image compression + testing for so long, it was now a useful benchmark. (Note: This + picture doesn't show very much.)