fix Makefile and README.md for 2000/bmeyer
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@@ -1,215 +1,329 @@
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#!/bin/make
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# 2000 makefile
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#!/usr/bin/env make
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#
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# Copyright (C) Simon Cooper, Landon Curt Noll, Peter Seebach
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# and Leonid A. Broukhis, 2000.
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# All Rights Reserved. Permission for personal, educational or non-profit
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# use is granted provided this this copyright and notice are included in its
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# entirety and remains unaltered. All other uses must receive prior permission
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# from the contest judges.
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# IOCCC 2000 winning entry - bmeyer
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SHELL= /bin/sh
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CAT= cat
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RM= rm
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SED= sed
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TRUE= true
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#CINCLUDE= -I ${HOMEBREW_PREFIX}/include/SDL2
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# optimization
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################################################################################
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#
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# Most compiles will safely use -O2. Some can use only -O.
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# A few compilers have broken optimizers and thus you may
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# not want anything.
|
||||
# Regarding individual entries:
|
||||
#
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||||
# IOCCC winning entry code may not work on your system. Even with standards,
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# conditions and build environments change, especially when it comes to more
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# extreme code such you might find in an IOCCC winner. Moreover, what was
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# allowed and liked in one IOCCC contest may no longer be liked/allowed in
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# later IOCCC years.
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#
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# Corrections on winning author and fixing typos in remarks are VERY WELCOME.
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#
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# GitHub pull requests are welcome:
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#
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# If you have a patch that might make running an entry work in modern Unix-like
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# environments, please create a GitHub pull request for the IOCCC judges to
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# consider.
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#
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# Suggestions and corrections regarding Makefiles, winning author information,
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# fixing typos in remarks, and code patches are welcome via opening a GitHub
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# issue or better yet, by creating a GitHub pull request for the IOCCC judges
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# to consider. To form a GitHub issue or GitHub pull, please visit:
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#
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# https://github.com/ioccc-src/winner
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#
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################################################################################
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# This work by Landon Curt Noll and Leonid A. Broukhis is licensed under:
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#
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# Creative Commons Attribution-ShareAlike 3.0 Unported License.
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#
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# See: http://creativecommons.org/licenses/by-sa/3.0/
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#############################
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# shell used by this Makefile
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#############################
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#
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SHELL= bash
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#######################
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# common tool locations
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#######################
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#
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include ../../var.mk
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# Set X11_LIBDIR to the directory where the X11 library resides
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#
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#X11_LIBDIR= /usr/X11R6/lib
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#X11_LIBDIR= /usr/X11/lib
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X11_LIBDIR= /opt/X11/lib
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# Set X11_INCLUDEDIR to the directory where the X11 include files reside
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#
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#X11_INCDIR= /usr/X11R6/include
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#X11_INCDIR= /usr/X11/include
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X11_INCDIR= /opt/X11/include
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# Common C compiler warnings to silence
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#
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#CSILENCE=
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CSILENCE= -Wno-format -Wno-parentheses -Wno-string-plus-int
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# Common C compiler warning flags
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#
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#CWARN= ${CSILENCE}
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#CWARN= -Wall ${CSILENCE}
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#CWARN= -Wall -Wextra ${CSILENCE}
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CWARN= -Wall -Wextra -pedantic ${CSILENCE}
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# Compiler standard
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#
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#CSTD=
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#CSTD= -ansi
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CSTD= -std=gnu99
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# Compiler bit architecture
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#
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# Some entries require 32-bitness:
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# ARCH= -m32
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#
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# Some entries require 64-bitness:
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# ARCH= -m64
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#
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# By default we assume nothing:
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#
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ARCH=
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# Defines that are needed to compile
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#
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#CDEFINE=
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CDEFINE= -DY=
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# Include files that are needed to compile
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#
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CINCLUDE=
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#CINCLUDE= -include stdlib.h
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#CINCLUDE= -include stdio.h
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#CINCLUDE= -include stdlib.h -include stdio.h
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#CINCLUDE= -I ${X11_INCDIR}
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#CINCLUDE= `${SDL2_CONFIG} --cflags`
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# Optimization
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#
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# Most compiles will safely use -O2. Some can use only -O1 or -O.
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# A few compilers have broken optimizers or this entry make break
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# under those buggy optimizers and thus you may not want anything.
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# Reasonable compilers will allow for -O3.
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#
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#OPT=
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#OPT= -O
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OPT= -O2
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#OPT= -O1
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#OPT= -O2
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OPT= -O3
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# flags for ANSI compiles
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# Default flags for ANSI C compilation
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#
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# NOTE: Some ANSI compilers make use of -Xa to turn on ANSI mode,
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# others such as gcc may want -ansi, others (Compaq Tru64 Unix)
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# want -std1, and others may want nothing at all.
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# Adjust the CFLAGS line as needed.
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#
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# NOTE: Some compilers cannot optimize, or optimize some entries
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# incorrectly. You might want to turn on -O to see if your
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# compiler can handle them.
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#
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#
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#CFLAGS= -Xa ${OPT}
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#CFLAGS= -std1 $(OPT)
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CFLAGS= -ansi ${OPT}
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CFLAGS= ${CSTD} ${CWARN} ${ARCH} ${CDEFINE} ${CINCLUDE} ${OPT}
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NO_ANSI_CFLAGS=
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#NO_ANSI_CFLAGS=
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# Libraries needed to build
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#
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#LIBS=
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LIBS= -lm
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#LIBS= -L ${X11_LIBDIR} -lX11
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#LIBS= `${SDL2_CONFIG} --libs`
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# NOTE: On some systems, the library path does not include the location
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# of the X11 libraries. You might need to use a -L/path/to/X11/lib/dir
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# in order to compile with these libs.
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#
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X11CCFLAGS= -I/usr/X11R6/include -I/usr/X11R6/include/X11 -I/usr/include/X11
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#X11CCFLAGS=
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X11LDFLAGS= -L/usr/X11R6/lib
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#X11LDFLAGS=
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# Perl
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#
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PERL= perl
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#PERL= perl5
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# ANSI compiler
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#
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# Set CC to the name of your ANSI compiler.
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#
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# Some entries seem to need gcc. If you have gcc, set
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# both CC and MAY_NEED_GCC to gcc.
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#
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# If you do not have gcc, set CC to the name of your ANSI compiler, and
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# set MAY_NEED_GCC to either ${CC} (and hope for the best) or to just :
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# to disable such programs.
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# C compiler to use
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#
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CC= cc
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MAY_NEED_GCC= gcc
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#CC=clang
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#CC=gcc
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# winners that compile under ANSI C
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# Compiler add-ons or replacements for clang only
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#
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WINNERS= anderson schneiderwent primenum bellard bmeyer briddlebane dhyang \
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dmy2jd jarijyrki dlowe natori rince robison thadgavin tomx
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ALT_NAMES= schneiderwent.orig briddlebane.orig thadgavin.orig
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DATA_FILES= schneiderwent_files bmeyer_files jarijyrki_files
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all: ${WINNERS}
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# Best use of flags
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ifeq ($(CC),clang)
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#
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anderson: anderson.c
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${CC} ${CFLAGS} $? -o $@
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# Most Timely Output
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CSILENCE+= -Wno-comma -Wno-disabled-macro-expansion -Wno-float-conversion \
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-Wno-format-nonliteral -Wno-missing-prototypes \
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-Wno-missing-variable-declarations -Wno-poison-system-directories \
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-Wno-shadow -Wno-shorten-64-to-32 -Wno-sign-conversion \
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-Wno-strict-prototypes
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#
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schneiderwent: schneiderwent.c
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${CC} ${CFLAGS} $? -o $@
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schneiderwent_files: schneiderwent.data
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schneiderwent.orig: schneiderwent.orig.c
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${CC} ${CFLAGS} $? -o $@
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# Best Abuse of CPP
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CWARN+= -Weverything
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#
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primenum: primenum.c
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${CC} ${CFLAGS} $? -o $@
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endif
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# Most Specific Output
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# Specific add-ons or replacements for gcc only
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#
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bellard: bellard.c
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${CC} ${CFLAGS} $? -o $@
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ifeq ($(CC),gcc)
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#
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#CSILENCE+=
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#
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#CWARN+=
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#
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endif
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# Best Utility
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#
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# machines operating in 64 bit mode:
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#
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bmeyer: bmeyer.c
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${CC} -DY= -O6 $? -o $@ -lm
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#
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# linux/x86, glibc 2.0, libc4/5:
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#
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# bmeyer: bmeyer.c
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# ${CC} -DY="__setfpucw(0x127f)" -O6 $? -o $@ -lm
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#
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# linux/x86, glibc 2.1:
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#
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# bmeyer: bmeyer.c
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# ${MAY_NEED_GCC} -DY='int x=0x127f; __asm__ ("fldcw %0" : : "m" (*&x))' \
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# -O6 $? -o $@ -lm
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bmeyer_files: lavabus.pgm lenna.glic michael.pgm
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# Best Abuse of User
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##############################
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# Special flags for this entry
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##############################
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#
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briddlebane: briddlebane.c
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${CC} ${CFLAGS} $? -o $@ -lm
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briddlebane.orig: briddlebane.orig.c
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${CC} ${CFLAGS} $? -o $@ -lm
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# Best Layout
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ENTRY= bmeyer
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PROG= ${ENTRY}
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#
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dhyang: dhyang.c
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${CC} ${CFLAGS} $? -o $@
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dmy2jd: dmy2jd.c
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${CC} ${CFLAGS} $? -o $@
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# Best of Show
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OBJ= ${PROG}.o
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DATA= lavabus.pgm lenna.glic michael.pgm
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TARGET= ${PROG}
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#
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jarijyrki: jarijyrki.c
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${CC} ${X11CCFLAGS} ${CFLAGS} -DNeedFunctionPrototypes \
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-DU=40 -DT=98 '-Dz=(T+1)*U*U' -DQ=80 -DS=20 -DN=10 -DB=5 -DG=23 \
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-Dp=7 '-DM=((p+1)*Q)+S' '-DH=(G*S)+S+S' -DC=XK_Up -DL=XK_Down \
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-DO=XK_Left -DV=XK_Right -DR=XK_Escape -D_=XK_BackSpace \
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$? -o $@ ${X11LDFLAGS} -lX11
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ALT_OBJ=
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ALT_TARGET=
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jarijyrki_files: sheet1.info
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# Worst Abuse of the Rules
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#################
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# build the entry
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#################
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#
|
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# NOTE: You will need to adjust this path to the place where Perl has been
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# installed on your system. Running "perl -V" may help you locate
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# this place.
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#
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# The following bit of perl may help determining the values you need:
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#
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# perl -MConfig -e 'print "$Config{archlibexp}/CORE\n"'
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#
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#
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dlowe: dlowe.c
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${CC} ${NO_ANSI_CFLAGS} -DPERL_POLLUTE \
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`${PERL} -MExtUtils::Embed -e ccopts` $? -o $@ \
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`${PERL} -MExtUtils::Embed -e ldopts`
|
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# Best Small Program
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||||
#
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natori: natori.c
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${CC} ${CFLAGS} $? -o $@ -lm
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|
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# Astronomically Obfuscated
|
||||
#
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||||
rince: rince.c
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${CC} ${X11CCFLAGS} ${CFLAGS} -DM_PI=3.14159265358979323846 \
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$? -o $@ -lm ${X11LDFLAGS} -lX11
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# Best game
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#
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robison: robison.c
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${CC} ${CFLAGS} $? -o $@
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# Most Portable Output
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||||
#
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thadgavin: thadgavin.c
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${CC} ${CFLAGS} $? -o $@ -lcurses -lm
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thadgavin.orig: thadgavin.orig.c
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${CC} ${CFLAGS} $? -o $@ -lncurses -lm
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# Most Complete Program
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#
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tomx: tomx.c
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${CC} ${CFLAGS} $? -o $@
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everything: ${WINNERS} ${ALT_NAMES} ${DATA_FILES}
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|
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clean:
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||||
${RM} -f *.o a.out core ${WINNERS}
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||||
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clobber: clean
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||||
${RM} -f ${WINNERS}
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${RM} -f ${ALT_NAMES}
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nuke: clobber
|
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all: data ${TARGET}
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@${TRUE}
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||||
|
||||
install: all
|
||||
${CAT} ${WINNERS} ${ALT_NAMES} > /dev/null
|
||||
.PHONY: all alt data everything clean clobber install \
|
||||
love haste waste maker easter_egg sandwich \
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supernova deep_magic magic charon pluto
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|
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${PROG}: ${PROG}.c
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||||
${CC} ${CFLAGS} $< -o $@ ${LIBS}
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|
||||
# alternative executable
|
||||
#
|
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alt: data ${ALT_TARGET}
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@${TRUE}
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||||
|
||||
# data files
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||||
#
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||||
data: ${DATA}
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||||
@${TRUE}
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||||
|
||||
# both all and alt
|
||||
#
|
||||
everything: all alt
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||||
|
||||
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###############
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||||
# 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 $${RANDOM} magic"
|
||||
@echo "chongo '<was here>' /\\oo/\\"
|
||||
@echo "Eggy"
|
||||
|
||||
sandwich: easter_egg
|
||||
@if [ `id -u` -eq 0 ]; then \
|
||||
echo 'Okay.'; \
|
||||
echo "$${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"
|
||||
+315
-268
@@ -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.pgm >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.pgm >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.)
|
||||
Reference in new issue
Block a user