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-rw-r--r--AUTHORS7
-rw-r--r--ChangeLog10
-rw-r--r--INSTALL60
-rw-r--r--Makefile.in104
-rw-r--r--NEWS3
-rw-r--r--README29
-rwxr-xr-xconfigure175
-rw-r--r--decoder.cc363
-rw-r--r--main.cc114
-rwxr-xr-xtestsuite/check.sh43
-rw-r--r--testsuite/test.txt676
-rw-r--r--testsuite/test.txt.lzbin0 -> 11518 bytes
12 files changed, 1584 insertions, 0 deletions
diff --git a/AUTHORS b/AUTHORS
new file mode 100644
index 0000000..a7b5945
--- /dev/null
+++ b/AUTHORS
@@ -0,0 +1,7 @@
+Lzd was written by Antonio Diaz Diaz.
+
+The ideas embodied in lzd are due to (at least) the following people:
+Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrey Markov (for
+the definition of Markov chains), G.N.N. Martin (for the definition of
+range encoding), and Igor Pavlov (for putting all the above together in
+LZMA).
diff --git a/ChangeLog b/ChangeLog
new file mode 100644
index 0000000..3a64682
--- /dev/null
+++ b/ChangeLog
@@ -0,0 +1,10 @@
+2013-03-21 Antonio Diaz Diaz <ant_diaz@teleline.es>
+
+ * Version 0.1 released.
+
+
+Copyright (C) 2013 Antonio Diaz Diaz.
+
+This file is a collection of facts, and thus it is not copyrightable,
+but just in case, you have unlimited permission to copy, distribute and
+modify it.
diff --git a/INSTALL b/INSTALL
new file mode 100644
index 0000000..54406be
--- /dev/null
+++ b/INSTALL
@@ -0,0 +1,60 @@
+Requirements
+------------
+You will need a C++ compiler.
+I use gcc 4.7.2 and 3.3.6, but the code should compile with any
+standards compliant compiler.
+Gcc is available at http://gcc.gnu.org.
+
+
+Procedure
+---------
+1. Unpack the archive if you have not done so already:
+
+ lzip -cd lzip[version].tar.lz | tar -xf -
+or
+ gzip -cd lzip[version].tar.gz | tar -xf -
+
+This creates the directory ./lzip[version] containing the source from
+the main archive.
+
+2. Change to lzip directory and run configure.
+ (Try 'configure --help' for usage instructions).
+
+ cd lzip[version]
+ ./configure
+
+3. Run make.
+
+ make
+
+4. Optionally, type 'make check' to run the tests that come with lzip.
+
+5. Type 'make install' to install the program and any data files and
+ documentation.
+
+ You can install only the program, the info manual or the man page
+ typing 'make install-bin', 'make install-info' or 'make install-man'
+ respectively.
+
+
+Another way
+-----------
+You can also compile lzip into a separate directory. To do this, you
+must use a version of 'make' that supports the 'VPATH' variable, such
+as GNU 'make'. 'cd' to the directory where you want the object files
+and executables to go and run the 'configure' script. 'configure'
+automatically checks for the source code in '.', in '..' and in the
+directory that 'configure' is in.
+
+'configure' recognizes the option '--srcdir=DIR' to control where to
+look for the sources. Usually 'configure' can determine that directory
+automatically.
+
+After running 'configure', you can run 'make' and 'make install' as
+explained above.
+
+
+Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013 Antonio Diaz Diaz.
+
+This file is free documentation: you have unlimited permission to copy,
+distribute and modify it.
diff --git a/Makefile.in b/Makefile.in
new file mode 100644
index 0000000..d313f51
--- /dev/null
+++ b/Makefile.in
@@ -0,0 +1,104 @@
+
+DISTNAME = $(pkgname)-$(pkgversion)
+INSTALL = install
+INSTALL_PROGRAM = $(INSTALL) -p -m 755
+INSTALL_DATA = $(INSTALL) -p -m 644
+INSTALL_DIR = $(INSTALL) -d -m 755
+SHELL = /bin/sh
+
+objs = main.o
+
+
+.PHONY : all install install-bin install-info install-man install-strip \
+ uninstall uninstall-bin uninstall-info uninstall-man \
+ doc info man check dist clean distclean
+
+all : $(progname)
+
+$(progname) : $(objs)
+ $(CXX) $(LDFLAGS) -o $@ $(objs)
+
+$(progname)_profiled : $(objs)
+ $(CXX) $(LDFLAGS) -pg -o $@ $(objs)
+
+main.o : main.cc
+ $(CXX) $(CPPFLAGS) $(CXXFLAGS) -DPROGVERSION=\"$(pkgversion)\" -c -o $@ $<
+
+%.o : %.cc
+ $(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<
+
+$(objs) : Makefile
+main.o : decoder.cc
+
+
+doc :
+
+info : $(VPATH)/doc/$(pkgname).info
+
+$(VPATH)/doc/$(pkgname).info : $(VPATH)/doc/$(pkgname).texinfo
+ cd $(VPATH)/doc && makeinfo $(pkgname).texinfo
+
+man : $(VPATH)/doc/$(progname).1
+
+$(VPATH)/doc/$(progname).1 : $(progname)
+ help2man -n 'educational decompressor for lzip files' \
+ -o $@ --no-info ./$(progname)
+
+Makefile : $(VPATH)/configure $(VPATH)/Makefile.in
+ ./config.status
+
+check : all
+ @$(VPATH)/testsuite/check.sh $(VPATH)/testsuite $(pkgversion)
+
+install : install-bin
+
+install-bin : all
+ if [ ! -d "$(DESTDIR)$(bindir)" ] ; then $(INSTALL_DIR) "$(DESTDIR)$(bindir)" ; fi
+ $(INSTALL_PROGRAM) ./$(progname) "$(DESTDIR)$(bindir)/$(progname)"
+
+install-info :
+ if [ ! -d "$(DESTDIR)$(infodir)" ] ; then $(INSTALL_DIR) "$(DESTDIR)$(infodir)" ; fi
+ $(INSTALL_DATA) $(VPATH)/doc/$(pkgname).info "$(DESTDIR)$(infodir)/$(pkgname).info"
+ -install-info --info-dir="$(DESTDIR)$(infodir)" "$(DESTDIR)$(infodir)/$(pkgname).info"
+
+install-man :
+ if [ ! -d "$(DESTDIR)$(mandir)/man1" ] ; then $(INSTALL_DIR) "$(DESTDIR)$(mandir)/man1" ; fi
+ $(INSTALL_DATA) $(VPATH)/doc/$(progname).1 "$(DESTDIR)$(mandir)/man1/$(progname).1"
+
+install-strip : all
+ $(MAKE) INSTALL_PROGRAM='$(INSTALL_PROGRAM) -s' install
+
+uninstall : uninstall-bin uninstall-info uninstall-man
+
+uninstall-bin :
+ -rm -f "$(DESTDIR)$(bindir)/$(progname)"
+
+uninstall-info :
+ -install-info --info-dir="$(DESTDIR)$(infodir)" --remove "$(DESTDIR)$(infodir)/$(pkgname).info"
+ -rm -f "$(DESTDIR)$(infodir)/$(pkgname).info"
+
+uninstall-man :
+ -rm -f "$(DESTDIR)$(mandir)/man1/$(progname).1"
+
+dist : doc
+ ln -sf $(VPATH) $(DISTNAME)
+ tar -cvf $(DISTNAME).tar \
+ $(DISTNAME)/AUTHORS \
+ $(DISTNAME)/ChangeLog \
+ $(DISTNAME)/INSTALL \
+ $(DISTNAME)/Makefile.in \
+ $(DISTNAME)/NEWS \
+ $(DISTNAME)/README \
+ $(DISTNAME)/configure \
+ $(DISTNAME)/testsuite/check.sh \
+ $(DISTNAME)/testsuite/test.txt \
+ $(DISTNAME)/testsuite/test.txt.lz \
+ $(DISTNAME)/*.cc
+ rm -f $(DISTNAME)
+ lzip -v -9 $(DISTNAME).tar
+
+clean :
+ -rm -f $(progname) $(progname)_profiled $(objs)
+
+distclean : clean
+ -rm -f Makefile config.status *.tar *.tar.lz
diff --git a/NEWS b/NEWS
new file mode 100644
index 0000000..5f057ce
--- /dev/null
+++ b/NEWS
@@ -0,0 +1,3 @@
+Changes in version 0.1:
+
+Initial release.
diff --git a/README b/README
new file mode 100644
index 0000000..c7546a7
--- /dev/null
+++ b/README
@@ -0,0 +1,29 @@
+Description
+
+Lzd is a very simplified decompressor for lzip files with an educational
+purpose. Studying its source is a good first step to understand how lzip
+works. It is not safe to use lzd for any real work.
+
+The source of lzd is also used in the lzip manual as a reference
+decompressor in the description of the lzip file format.
+
+Lzd decompresses from standard input to standard output. Lzd will
+correctly decompress the concatenation of two or more compressed files.
+The result is the concatenation of the corresponding decompressed data.
+Integrity of such concatenated compressed input is also verified.
+
+The ideas embodied in lzd are due to (at least) the following people:
+Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrey Markov (for
+the definition of Markov chains), G.N.N. Martin (for the definition of
+range encoding), and Igor Pavlov (for putting all the above together in
+LZMA).
+
+
+Copyright (C) 2013 Antonio Diaz Diaz.
+
+This file is free documentation: you have unlimited permission to copy,
+distribute and modify it.
+
+The file Makefile.in is a data file used by configure to produce the
+Makefile. It has the same copyright owner and permissions that configure
+itself.
diff --git a/configure b/configure
new file mode 100755
index 0000000..e2b6a47
--- /dev/null
+++ b/configure
@@ -0,0 +1,175 @@
+#! /bin/sh
+# configure script for Lzd - Educational decompressor for lzip files
+# Copyright (C) 2013 Antonio Diaz Diaz.
+#
+# This configure script is free software: you have unlimited permission
+# to copy, distribute and modify it.
+
+args=
+no_create=
+pkgname=lzd
+pkgversion=0.1
+progname=lzd
+srctrigger=decoder.cc
+
+# clear some things potentially inherited from environment.
+LC_ALL=C
+export LC_ALL
+srcdir=
+prefix=/usr/local
+exec_prefix='$(prefix)'
+bindir='$(exec_prefix)/bin'
+datarootdir='$(prefix)/share'
+infodir='$(datarootdir)/info'
+mandir='$(datarootdir)/man'
+CXX=g++
+CPPFLAGS=
+CXXFLAGS='-Wall -W -O2'
+LDFLAGS=
+
+# checking whether we are using GNU C++.
+if [ ! -x /bin/g++ ] &&
+ [ ! -x /usr/bin/g++ ] &&
+ [ ! -x /usr/local/bin/g++ ] ; then
+ CXX=c++
+ CXXFLAGS='-W -O2'
+fi
+
+# Loop over all args
+while [ -n "$1" ] ; do
+
+ # Get the first arg, and shuffle
+ option=$1
+ shift
+
+ # Add the argument quoted to args
+ args="${args} \"${option}\""
+
+ # Split out the argument for options that take them
+ case ${option} in
+ *=*) optarg=`echo ${option} | sed -e 's,^[^=]*=,,;s,/$,,'` ;;
+ esac
+
+ # Process the options
+ case ${option} in
+ --help | -h)
+ echo "Usage: configure [options]"
+ echo
+ echo "Options: [defaults in brackets]"
+ echo " -h, --help display this help and exit"
+ echo " -V, --version output version information and exit"
+ echo " --srcdir=DIR find the sources in DIR [. or ..]"
+ echo " --prefix=DIR install into DIR [${prefix}]"
+ echo " --exec-prefix=DIR base directory for arch-dependent files [${exec_prefix}]"
+ echo " --bindir=DIR user executables directory [${bindir}]"
+ echo " --datarootdir=DIR base directory for doc and data [${datarootdir}]"
+ echo " --infodir=DIR info files directory [${infodir}]"
+ echo " --mandir=DIR man pages directory [${mandir}]"
+ echo " CXX=COMPILER C++ compiler to use [g++]"
+ echo " CPPFLAGS=OPTIONS command line options for the preprocessor [${CPPFLAGS}]"
+ echo " CXXFLAGS=OPTIONS command line options for the C++ compiler [${CXXFLAGS}]"
+ echo " LDFLAGS=OPTIONS command line options for the linker [${LDFLAGS}]"
+ echo
+ exit 0 ;;
+ --version | -V)
+ echo "Configure script for ${pkgname} version ${pkgversion}"
+ exit 0 ;;
+ --srcdir=*) srcdir=${optarg} ;;
+ --prefix=*) prefix=${optarg} ;;
+ --exec-prefix=*) exec_prefix=${optarg} ;;
+ --bindir=*) bindir=${optarg} ;;
+ --datarootdir=*) datarootdir=${optarg} ;;
+ --infodir=*) infodir=${optarg} ;;
+ --mandir=*) mandir=${optarg} ;;
+ --no-create) no_create=yes ;;
+
+ CXX=*) CXX=${optarg} ;;
+ CPPFLAGS=*) CPPFLAGS=${optarg} ;;
+ CXXFLAGS=*) CXXFLAGS=${optarg} ;;
+ LDFLAGS=*) LDFLAGS=${optarg} ;;
+
+ --* | *=* | *-*-*) ;;
+ *)
+ echo "configure: Unrecognized option: \"${option}\"; use --help for usage." 1>&2
+ exit 1 ;;
+ esac
+done
+
+# Find the source files, if location was not specified.
+srcdirtext=
+if [ -z "${srcdir}" ] ; then
+ srcdirtext="or . or .." ; srcdir=.
+ if [ ! -r "${srcdir}/${srctrigger}" ] ; then srcdir=.. ; fi
+ if [ ! -r "${srcdir}/${srctrigger}" ] ; then
+ ## the sed command below emulates the dirname command
+ srcdir=`echo $0 | sed -e 's,[^/]*$,,;s,/$,,;s,^$,.,'`
+ fi
+fi
+
+if [ ! -r "${srcdir}/${srctrigger}" ] ; then
+ exec 1>&2
+ echo
+ echo "configure: Can't find sources in ${srcdir} ${srcdirtext}"
+ echo "configure: (At least ${srctrigger} is missing)."
+ exit 1
+fi
+
+# Set srcdir to . if that's what it is.
+if [ "`pwd`" = "`cd "${srcdir}" ; pwd`" ] ; then srcdir=. ; fi
+
+echo
+if [ -z "${no_create}" ] ; then
+ echo "creating config.status"
+ rm -f config.status
+ cat > config.status << EOF
+#! /bin/sh
+# This file was generated automatically by configure. Do not edit.
+# Run this file to recreate the current configuration.
+#
+# This script is free software: you have unlimited permission
+# to copy, distribute and modify it.
+
+exec /bin/sh $0 ${args} --no-create
+EOF
+ chmod +x config.status
+fi
+
+echo "creating Makefile"
+echo "VPATH = ${srcdir}"
+echo "prefix = ${prefix}"
+echo "exec_prefix = ${exec_prefix}"
+echo "bindir = ${bindir}"
+echo "datarootdir = ${datarootdir}"
+echo "infodir = ${infodir}"
+echo "mandir = ${mandir}"
+echo "CXX = ${CXX}"
+echo "CPPFLAGS = ${CPPFLAGS}"
+echo "CXXFLAGS = ${CXXFLAGS}"
+echo "LDFLAGS = ${LDFLAGS}"
+rm -f Makefile
+cat > Makefile << EOF
+# Makefile for Lzd - Educational decompressor for lzip files
+# Copyright (C) 2013 Antonio Diaz Diaz.
+# This file was generated automatically by configure. Do not edit.
+#
+# This Makefile is free software: you have unlimited permission
+# to copy, distribute and modify it.
+
+pkgname = ${pkgname}
+pkgversion = ${pkgversion}
+progname = ${progname}
+VPATH = ${srcdir}
+prefix = ${prefix}
+exec_prefix = ${exec_prefix}
+bindir = ${bindir}
+datarootdir = ${datarootdir}
+infodir = ${infodir}
+mandir = ${mandir}
+CXX = ${CXX}
+CPPFLAGS = ${CPPFLAGS}
+CXXFLAGS = ${CXXFLAGS}
+LDFLAGS = ${LDFLAGS}
+EOF
+cat "${srcdir}/Makefile.in" >> Makefile
+
+echo "OK. Now you can run make."
diff --git a/decoder.cc b/decoder.cc
new file mode 100644
index 0000000..fbfcdb3
--- /dev/null
+++ b/decoder.cc
@@ -0,0 +1,363 @@
+/* Lzd - Educational decompressor for lzip files
+ Copyright (C) 2013 Antonio Diaz Diaz.
+
+ This program is free software: you have unlimited permission
+ to copy, distribute and modify it.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+*/
+
+class State
+ {
+ int st;
+
+public:
+ enum { states = 12 };
+ State() : st( 0 ) {}
+ int operator()() const { return st; }
+ bool is_char() const { return st < 7; }
+
+ void set_char()
+ {
+ static const int next[states] = { 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5 };
+ st = next[st];
+ }
+
+ void set_match() { st = ( ( st < 7 ) ? 7 : 10 ); }
+ void set_rep() { st = ( ( st < 7 ) ? 8 : 11 ); }
+ void set_short_rep() { st = ( ( st < 7 ) ? 9 : 11 ); }
+ };
+
+
+enum {
+ literal_context_bits = 3,
+ pos_state_bits = 2,
+ pos_states = 1 << pos_state_bits,
+ pos_state_mask = pos_states - 1,
+
+ max_dis_states = 4,
+ dis_slot_bits = 6,
+ start_dis_model = 4,
+ end_dis_model = 14,
+ modeled_distances = 1 << (end_dis_model / 2), // 128
+ dis_align_bits = 4,
+ dis_align_size = 1 << dis_align_bits,
+
+ len_low_bits = 3,
+ len_mid_bits = 3,
+ len_high_bits = 8,
+ len_low_symbols = 1 << len_low_bits,
+ len_mid_symbols = 1 << len_mid_bits,
+ len_high_symbols = 1 << len_high_bits,
+ max_len_symbols = len_low_symbols + len_mid_symbols + len_high_symbols,
+ min_match_len = 2, // must be 2
+
+ bit_model_move_bits = 5,
+ bit_model_total_bits = 11,
+ bit_model_total = 1 << bit_model_total_bits };
+
+
+struct Bit_model
+ {
+ int probability;
+ Bit_model() : probability( bit_model_total / 2 ) {}
+ };
+
+struct Len_model
+ {
+ Bit_model choice1;
+ Bit_model choice2;
+ Bit_model bm_low[pos_states][len_low_symbols];
+ Bit_model bm_mid[pos_states][len_mid_symbols];
+ Bit_model bm_high[len_high_symbols];
+ };
+
+
+class Range_decoder
+ {
+ uint32_t code;
+ uint32_t range;
+
+public:
+ Range_decoder() : code( 0 ), range( 0xFFFFFFFFU )
+ {
+ for( int i = 0; i < 5; ++i ) code = (code << 8) | std::getc( stdin );
+ }
+
+ int decode( const int num_bits )
+ {
+ int symbol = 0;
+ for( int i = 0; i < num_bits; ++i )
+ {
+ range >>= 1;
+ symbol <<= 1;
+ if( code >= range ) { code -= range; symbol |= 1; }
+ if( range <= 0x00FFFFFFU ) // normalize
+ { range <<= 8; code = (code << 8) | std::getc( stdin ); }
+ }
+ return symbol;
+ }
+
+ int decode_bit( Bit_model & bm )
+ {
+ int symbol;
+ const uint32_t bound = ( range >> bit_model_total_bits ) * bm.probability;
+ if( code < bound )
+ {
+ range = bound;
+ bm.probability += (bit_model_total - bm.probability) >> bit_model_move_bits;
+ symbol = 0;
+ }
+ else
+ {
+ range -= bound;
+ code -= bound;
+ bm.probability -= bm.probability >> bit_model_move_bits;
+ symbol = 1;
+ }
+ if( range <= 0x00FFFFFFU ) // normalize
+ { range <<= 8; code = (code << 8) | std::getc( stdin ); }
+ return symbol;
+ }
+
+ int decode_tree( Bit_model bm[], const int num_bits )
+ {
+ int symbol = 1;
+ for( int i = 0; i < num_bits; ++i )
+ symbol = ( symbol << 1 ) | decode_bit( bm[symbol] );
+ return symbol - (1 << num_bits);
+ }
+
+ int decode_tree_reversed( Bit_model bm[], const int num_bits )
+ {
+ int symbol = decode_tree( bm, num_bits );
+ int reversed_symbol = 0;
+ for( int i = 0; i < num_bits; ++i )
+ {
+ reversed_symbol = ( reversed_symbol << 1 ) | ( symbol & 1 );
+ symbol >>= 1;
+ }
+ return reversed_symbol;
+ }
+
+ int decode_matched( Bit_model bm[], const int match_byte )
+ {
+ Bit_model * const bm1 = bm + 0x100;
+ int symbol = 1;
+ for( int i = 7; i >= 0; --i )
+ {
+ const int match_bit = ( match_byte >> i ) & 1;
+ const int bit = decode_bit( bm1[(match_bit<<8)+symbol] );
+ symbol = ( symbol << 1 ) | bit;
+ if( match_bit != bit )
+ {
+ while( symbol < 0x100 )
+ symbol = ( symbol << 1 ) | decode_bit( bm[symbol] );
+ break;
+ }
+ }
+ return symbol - 0x100;
+ }
+
+ int decode_len( Len_model & lm, const int pos_state )
+ {
+ if( decode_bit( lm.choice1 ) == 0 )
+ return min_match_len +
+ decode_tree( lm.bm_low[pos_state], len_low_bits );
+ if( decode_bit( lm.choice2 ) == 0 )
+ return min_match_len + len_low_symbols +
+ decode_tree( lm.bm_mid[pos_state], len_mid_bits );
+ return min_match_len + len_low_symbols + len_mid_symbols +
+ decode_tree( lm.bm_high, len_high_bits );
+ }
+ };
+
+
+class LZ_decoder
+ {
+ unsigned long long partial_data_pos;
+ Range_decoder rdec;
+ const unsigned dictionary_size;
+ uint8_t * const buffer; // output buffer
+ unsigned pos; // current pos in buffer
+ unsigned stream_pos; // first byte not yet written to stdout
+ uint32_t crc_;
+
+ void flush_data();
+
+ uint8_t get_byte( const unsigned distance ) const
+ {
+ int i = pos - distance - 1;
+ if( i < 0 ) i += dictionary_size;
+ return buffer[i];
+ }
+
+ void put_byte( const uint8_t b )
+ {
+ buffer[pos] = b;
+ if( ++pos >= dictionary_size ) flush_data();
+ }
+
+public:
+ LZ_decoder( const unsigned dict_size )
+ :
+ partial_data_pos( 0 ),
+ dictionary_size( dict_size ),
+ buffer( new uint8_t[dictionary_size] ),
+ pos( 0 ),
+ stream_pos( 0 ),
+ crc_( 0xFFFFFFFFU )
+ { buffer[dictionary_size-1] = 0; } // prev_byte of first_byte
+
+ ~LZ_decoder() { delete[] buffer; }
+
+ unsigned crc() const { return crc_ ^ 0xFFFFFFFFU; }
+ unsigned long long data_position() const { return partial_data_pos + pos; }
+
+ bool decode_member();
+ };
+
+
+class CRC32
+ {
+ uint32_t data[256]; // Table of CRCs of all 8-bit messages.
+
+public:
+ CRC32()
+ {
+ for( unsigned n = 0; n < 256; ++n )
+ {
+ unsigned c = n;
+ for( int k = 0; k < 8; ++k )
+ { if( c & 1 ) c = 0xEDB88320U ^ ( c >> 1 ); else c >>= 1; }
+ data[n] = c;
+ }
+ }
+
+ void update( uint32_t & crc, const uint8_t * buffer, const int size ) const
+ {
+ for( int i = 0; i < size; ++i )
+ crc = data[(crc^buffer[i])&0xFF] ^ ( crc >> 8 );
+ }
+ };
+
+const CRC32 crc32;
+
+
+void LZ_decoder::flush_data()
+ {
+ if( pos > stream_pos )
+ {
+ const unsigned size = pos - stream_pos;
+ crc32.update( crc_, buffer + stream_pos, size );
+ errno = 0;
+ if( std::fwrite( buffer + stream_pos, 1, size, stdout ) != size )
+ { std::fprintf( stderr, "Write error: %s\n", std::strerror( errno ) );
+ std::exit( 1 ); }
+ if( pos >= dictionary_size ) { partial_data_pos += pos; pos = 0; }
+ stream_pos = pos;
+ }
+ }
+
+
+bool LZ_decoder::decode_member() // Returns false if error
+ {
+ Bit_model bm_literal[1<<literal_context_bits][0x300];
+ Bit_model bm_match[State::states][pos_states];
+ Bit_model bm_rep[State::states];
+ Bit_model bm_rep0[State::states];
+ Bit_model bm_rep1[State::states];
+ Bit_model bm_rep2[State::states];
+ Bit_model bm_len[State::states][pos_states];
+ Bit_model bm_dis_slot[max_dis_states][1<<dis_slot_bits];
+ Bit_model bm_dis[modeled_distances-end_dis_model];
+ Bit_model bm_align[dis_align_size];
+ Len_model match_len_model;
+ Len_model rep_len_model;
+ unsigned rep0 = 0; // rep[0-3] latest four distances
+ unsigned rep1 = 0; // used for efficient coding of
+ unsigned rep2 = 0; // repeated distances
+ unsigned rep3 = 0;
+ State state;
+
+ while( !std::feof( stdin ) && !std::ferror( stdin ) )
+ {
+ const int pos_state = data_position() & pos_state_mask;
+ if( rdec.decode_bit( bm_match[state()][pos_state] ) == 0 ) // 1st bit
+ {
+ const uint8_t prev_byte = get_byte( 0 );
+ const int literal_state = prev_byte >> ( 8 - literal_context_bits );
+ Bit_model * const bm = bm_literal[literal_state];
+ if( state.is_char() )
+ put_byte( rdec.decode_tree( bm, 8 ) );
+ else
+ put_byte( rdec.decode_matched( bm, get_byte( rep0 ) ) );
+ state.set_char();
+ }
+ else
+ {
+ int len;
+ if( rdec.decode_bit( bm_rep[state()] ) == 1 ) // 2nd bit
+ {
+ if( rdec.decode_bit( bm_rep0[state()] ) == 0 ) // 3rd bit
+ {
+ if( rdec.decode_bit( bm_len[state()][pos_state] ) == 0 ) // 4th bit
+ { state.set_short_rep(); put_byte( get_byte( rep0 ) ); continue; }
+ }
+ else
+ {
+ unsigned distance;
+ if( rdec.decode_bit( bm_rep1[state()] ) == 0 ) // 4th bit
+ distance = rep1;
+ else
+ {
+ if( rdec.decode_bit( bm_rep2[state()] ) == 0 ) // 5th bit
+ distance = rep2;
+ else
+ { distance = rep3; rep3 = rep2; }
+ rep2 = rep1;
+ }
+ rep1 = rep0;
+ rep0 = distance;
+ }
+ len = rdec.decode_len( rep_len_model, pos_state );
+ state.set_rep();
+ }
+ else
+ {
+ rep3 = rep2; rep2 = rep1; rep1 = rep0;
+ len = rdec.decode_len( match_len_model, pos_state );
+ const int dis_state = std::min( len - min_match_len, max_dis_states - 1 );
+ const int dis_slot =
+ rdec.decode_tree( bm_dis_slot[dis_state], dis_slot_bits );
+ if( dis_slot < start_dis_model ) rep0 = dis_slot;
+ else
+ {
+ const int direct_bits = ( dis_slot >> 1 ) - 1;
+ rep0 = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
+ if( dis_slot < end_dis_model )
+ rep0 += rdec.decode_tree_reversed( bm_dis + rep0 - dis_slot - 1,
+ direct_bits );
+ else
+ {
+ rep0 += rdec.decode( direct_bits - dis_align_bits ) << dis_align_bits;
+ rep0 += rdec.decode_tree_reversed( bm_align, dis_align_bits );
+ if( rep0 == 0xFFFFFFFFU ) // Marker found
+ {
+ flush_data();
+ return ( len == min_match_len ); // End Of Stream marker
+ }
+ }
+ }
+ state.set_match();
+ if( rep0 >= dictionary_size || ( rep0 >= pos && !partial_data_pos ) )
+ return false;
+ }
+ for( int i = 0; i < len; ++i )
+ put_byte( get_byte( rep0 ) );
+ }
+ }
+ return false;
+ }
diff --git a/main.cc b/main.cc
new file mode 100644
index 0000000..e9c16a9
--- /dev/null
+++ b/main.cc
@@ -0,0 +1,114 @@
+/* Lzd - Educational decompressor for lzip files
+ Copyright (C) 2013 Antonio Diaz Diaz.
+
+ This program is free software: you have unlimited permission
+ to copy, distribute and modify it.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+*/
+/*
+ Return values: 0 for a normal exit, 1 for environmental problems
+ (file not found, invalid flags, I/O errors, etc), 2 to indicate a
+ corrupt or invalid input file.
+*/
+
+#include <algorithm>
+#include <cerrno>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <stdint.h>
+#include <unistd.h>
+#if defined(__MSVCRT__) || defined(__OS2__)
+#include <io.h>
+#endif
+
+#include "decoder.cc"
+
+
+enum { min_dictionary_size = 1 << 12,
+ max_dictionary_size = 1 << 29 };
+
+typedef uint8_t File_header[6]; // 0-3 magic, 4 version, 5 coded_dict_size
+
+typedef uint8_t File_trailer[20];
+ // 0-3 CRC32 of the uncompressed data
+ // 4-11 size of the uncompressed data
+ // 12-19 member size including header and trailer
+
+
+int main( const int argc, const char * const argv[] )
+ {
+ if( argc > 1 )
+ {
+ std::printf( "Lzd %s - Educational decompressor for lzip files.\n",
+ PROGVERSION );
+ std::printf( "Study the source to learn how a simple lzip decompressor works.\n"
+ "It is not safe to use it for any real work.\n"
+ "\nUsage: %s < file.lz > file\n", argv[0] );
+ std::printf( "Lzd decompresses from standard input to standard output.\n"
+ "\nCopyright (C) 2013 Antonio Diaz Diaz.\n"
+ "This is free software: you are free to change and redistribute it.\n"
+ "There is NO WARRANTY, to the extent permitted by law.\n"
+ "Report bugs to lzip-bug@nongnu.org\n"
+ "Lzip home page: http://www.nongnu.org/lzip/lzip.html\n" );
+ return 0;
+ }
+
+#if defined(__MSVCRT__) || defined(__OS2__)
+ setmode( STDIN_FILENO, O_BINARY );
+ setmode( STDOUT_FILENO, O_BINARY );
+#endif
+
+ if( isatty( STDIN_FILENO ) )
+ {
+ std::fprintf( stderr, "I won't read compressed data from a terminal.\n"
+ "Try '%s --help' for more information.\n", argv[0] );
+ return 1;
+ }
+
+ for( bool first_member = true; ; first_member = false )
+ {
+ File_header header;
+ for( int i = 0; i < 6; ++i )
+ header[i] = std::getc( stdin );
+ if( std::feof( stdin ) || std::memcmp( header, "LZIP", 4 ) != 0 )
+ {
+ if( first_member )
+ { std::fprintf( stderr, "Bad magic number (file not in lzip format)\n" );
+ return 2; }
+ break;
+ }
+ if( header[4] != 1 )
+ {
+ std::fprintf( stderr, "Version %d member format not supported.\n",
+ header[4] );
+ return 2;
+ }
+ unsigned dict_size = 1 << ( header[5] & 0x1F );
+ dict_size -= ( dict_size / 16 ) * ( ( header[5] >> 5 ) & 7 );
+ if( dict_size < min_dictionary_size || dict_size > max_dictionary_size )
+ { std::fprintf( stderr, "Invalid dictionary size in member header\n" );
+ return 2; }
+
+ LZ_decoder decoder( dict_size );
+ if( !decoder.decode_member() )
+ { std::fprintf( stderr, "Data error\n" ); return 2; }
+
+ File_trailer trailer;
+ for( int i = 0; i < 20; ++i ) trailer[i] = std::getc( stdin );
+ unsigned crc = 0;
+ for( int i = 3; i >= 0; --i ) { crc <<= 8; crc += trailer[i]; }
+ unsigned long long data_size = 0;
+ for( int i = 11; i >= 4; --i ) { data_size <<= 8; data_size += trailer[i]; }
+ if( crc != decoder.crc() || data_size != decoder.data_position() )
+ { std::fprintf( stderr, "CRC error\n" ); return 2; }
+ }
+
+ if( std::fclose( stdout ) != 0 )
+ { std::fprintf( stderr, "Can't close stdout: %s\n", std::strerror( errno ) );
+ return 1; }
+ return 0;
+ }
diff --git a/testsuite/check.sh b/testsuite/check.sh
new file mode 100755
index 0000000..6dd7bb8
--- /dev/null
+++ b/testsuite/check.sh
@@ -0,0 +1,43 @@
+#! /bin/sh
+# check script for Lzd - Educational decompressor for lzip files
+# Copyright (C) 2013 Antonio Diaz Diaz.
+#
+# This script is free software: you have unlimited permission
+# to copy, distribute and modify it.
+
+LC_ALL=C
+export LC_ALL
+objdir=`pwd`
+testdir=`cd "$1" ; pwd`
+LZIP="${objdir}"/lzd
+framework_failure() { echo "failure in testing framework" ; exit 1 ; }
+
+if [ ! -x "${LZIP}" ] ; then
+ echo "${LZIP}: cannot execute"
+ exit 1
+fi
+
+if [ -d tmp ] ; then rm -rf tmp ; fi
+mkdir tmp
+cd "${objdir}"/tmp
+
+in="${testdir}"/test.txt
+in_lz="${testdir}"/test.txt.lz
+fail=0
+
+printf "testing lzd-%s..." "$2"
+
+"${LZIP}" < "${in_lz}" | cmp "${in}" - || fail=1
+printf .
+cat "${in_lz}" "${in_lz}" | "${LZIP}" > copy2 || fail=1
+cat "${in}" "${in}" | cmp copy2 - || fail=1
+printf .
+
+echo
+if [ ${fail} = 0 ] ; then
+ echo "tests completed successfully."
+ cd "${objdir}" && rm -r tmp
+else
+ echo "tests failed."
+fi
+exit ${fail}
diff --git a/testsuite/test.txt b/testsuite/test.txt
new file mode 100644
index 0000000..5b244d5
--- /dev/null
+++ b/testsuite/test.txt
@@ -0,0 +1,676 @@
+
+ GNU GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
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+software and other kinds of works.
+
+ The licenses for most software and other practical works are designed
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+share and change all versions of a program--to make sure it remains free
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+any other work released this way by its authors. You can apply it to
+your programs, too.
+
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+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
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+you modify it: responsibilities to respect the freedom of others.
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+ Developers that use the GNU GPL protect your rights with two steps:
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