diff --git a/pigz/Android.mk b/pigz/Android.mk
new file mode 100644
index 0000000..6ff50b8
--- /dev/null
+++ b/pigz/Android.mk
@@ -0,0 +1,32 @@
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := pigz
+LOCAL_MODULE_TAGS := eng
+LOCAL_MODULE_CLASS := RECOVERY_EXECUTABLES
+LOCAL_MODULE_PATH := $(TARGET_RECOVERY_ROOT_OUT)/sbin
+LOCAL_MODULES_TAGS = optional
+LOCAL_CFLAGS = 
+LOCAL_SRC_FILES = pigz.c yarn.c
+LOCAL_C_INCLUDES += $(LOCAL_PATH) \
+					external/zlib
+LOCAL_SHARED_LIBRARIES += libz libc
+
+include $(BUILD_EXECUTABLE)
+
+PIGZ_TOOLS := unpigz
+SYMLINKS := $(addprefix $(TARGET_RECOVERY_ROOT_OUT)/sbin/,$(PIGZ_TOOLS))
+$(SYMLINKS): PIGZ_BINARY := $(LOCAL_MODULE)
+$(SYMLINKS): $(LOCAL_INSTALLED_MODULE)
+	@echo "Symlink: $@ -> $(PIGZ_BINARY)"
+	@mkdir -p $(dir $@)
+	@rm -rf $@
+	$(hide) ln -sf $(PIGZ_BINARY) $@
+
+ALL_DEFAULT_INSTALLED_MODULES += $(SYMLINKS)
+
+# We need this so that the installed files could be picked up based on the
+# local module name
+ALL_MODULES.$(LOCAL_MODULE).INSTALLED := \
+    $(ALL_MODULES.$(LOCAL_MODULE).INSTALLED) $(SYMLINKS)
diff --git a/pigz/Makefile b/pigz/Makefile
new file mode 100644
index 0000000..fa47e2b
--- /dev/null
+++ b/pigz/Makefile
@@ -0,0 +1,47 @@
+CFLAGS=-O3
+
+pigz: pigz.o yarn.o
+	cc -o pigz pigz.o yarn.o -lpthread -lz
+	ln -f pigz unpigz
+
+pigz.o: pigz.c yarn.h
+
+yarn.o: yarn.c yarn.h
+
+dev: pigz pigzt pigzn
+
+pigzt: pigzt.o yarnt.o
+	cc -o pigzt pigzt.o yarnt.o -lpthread -lz
+
+pigzt.o: pigz.c yarn.h
+	cc -Wall -O3 -DDEBUG -g -c -o pigzt.o pigz.c
+
+yarnt.o: yarn.c yarn.h
+	cc -Wall -O3 -DDEBUG -g -c -o yarnt.o yarn.c
+
+pigzn: pigzn.o
+	cc -o pigzn pigzn.o -lz
+
+pigzn.o: pigz.c
+	cc -Wall -O3 -DDEBUG -DNOTHREAD -g -c -o pigzn.o pigz.c
+
+test: pigz
+	./pigz -kf pigz.c ; ./pigz -t pigz.c.gz
+	./pigz -kfb 32 pigz.c ; ./pigz -t pigz.c.gz
+	./pigz -kfp 1 pigz.c ; ./pigz -t pigz.c.gz
+	./pigz -kfz pigz.c ; ./pigz -t pigz.c.zz
+	./pigz -kfK pigz.c ; ./pigz -t pigz.c.zip
+	compress -f < pigz.c | ./unpigz | cmp - pigz.c
+	rm -f pigz.c.gz pigz.c.zz pigz.c.zip
+
+tests: dev test
+	./pigzn -kf pigz.c ; ./pigz -t pigz.c.gz
+	rm -f pigz.c.gz
+
+docs: pigz.pdf
+
+pigz.pdf: pigz.1
+	groff -mandoc -f H -T ps pigz.1 | ps2pdf - pigz.pdf
+
+clean:
+	rm -f *.o pigz unpigz pigzn pigzt pigz.c.gz pigz.c.zz pigz.c.zip
diff --git a/pigz/README b/pigz/README
new file mode 100644
index 0000000..bad49da
--- /dev/null
+++ b/pigz/README
@@ -0,0 +1,48 @@
+pigz 2.1.6 (17 Jan 2010) by Mark Adler
+
+pigz, which stands for Parallel Implementation of GZip, is a fully functional
+replacement for gzip that exploits multiple processors and multiple cores to
+the hilt when compressing data.
+
+pigz was written by Mark Adler, and uses the zlib and pthread libraries.
+
+This version of pigz is written to be portable across Unix-style operating
+systems that provide the zlib and pthread libraries.
+
+Type "make" in this directory to build the "pigz" executable.  You can then
+install the executable wherever you like in your path (e.g. /usr/local/bin/).
+Type "pigz" to see the command help and all of the command options.
+
+The latest version of pigz can be found at http://zlib.net/pigz/ .  You need
+zlib version 1.2.3 or later to compile pigz.  You can find the latest version
+of zlib at http://zlib.net/ .  You can look in pigz.c for the change history.
+
+Questions, comments, bug reports, fixes, etc. can be emailed to Mark at his
+address in the license below.
+
+The license from pigz.c is copied here:
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the author be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+
+  Mark Adler
+  madler@alumni.caltech.edu
+
+  Mark accepts donations for providing this software.  Donations are not
+  required or expected.  Any amount that you feel is appropriate would be
+  appreciated.  You can use this link:
+
+  https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=536055
diff --git a/pigz/pigz.1 b/pigz/pigz.1
new file mode 100644
index 0000000..567c6ca
--- /dev/null
+++ b/pigz/pigz.1
@@ -0,0 +1,187 @@
+.TH PIGZ 1 local
+.SH NAME
+pigz, unpigz \- compress or expand files
+.SH SYNOPSIS
+.ll +8
+.B pigz
+.RB [ " \-cdfhikKlLnNqrRtTz0..9 " ]
+[
+.B -b
+.I blocksize
+]
+[
+.B -p
+.I threads
+]
+[
+.B -S
+.I suffix
+]
+[
+.I "name \&..."
+]
+.ll -8
+.br
+.B unpigz
+.RB [ " \-cfhikKlLnNqrRtTz " ]
+[
+.B -b
+.I blocksize
+]
+[
+.B -p
+.I threads
+]
+[
+.B -S
+.I suffix
+]
+[
+.I "name \&..."
+]
+.SH DESCRIPTION
+.I Pigz
+compresses using threads to make use of multiple processors and cores.
+The input is broken up into 128 KB chunks with each compressed in parallel.
+The individual check value for each chunk is also calculated in parallel.
+The compressed data is written in order to the output, and a combined check
+value is calculated from the individual check values.
+.PP
+The compressed data format generated is in the gzip, zlib, or single-entry
+zip format using the deflate compression method.  The compression produces
+partial raw deflate streams which are concatenated by a single write thread
+and wrapped with the appropriate header and trailer, where the trailer
+contains the combined check value.
+.PP
+Each partial raw deflate stream is terminated by an empty stored block
+(using the Z_SYNC_FLUSH option of zlib), in order to end that partial bit
+stream at a byte boundary.  That allows the partial streams to be
+concatenated simply as sequences of bytes.  This adds a very small four to
+five byte overhead to the output for each input chunk.
+.PP
+The default input block size is 128K, but can be changed with the
+.B -b
+option.  The number of compress threads is set by default to the number
+of online processors,
+which can be changed using the 
+.B -p
+option.  Specifying
+.B -p 1
+avoids the use of threads entirely.
+.PP
+The input blocks, while compressed independently, have the last 32K of the
+previous block loaded as a preset dictionary to preserve the compression
+effectiveness of deflating in a single thread.  This can be turned off using
+the
+.B -i
+or
+.B --independent
+option, so that the blocks can be decompressed
+independently for partial error recovery or for random access.
+.PP
+Decompression can't be parallelized, at least not without specially prepared
+deflate streams for that purpose.  As a result,
+.I pigz
+uses a single thread
+(the main thread) for decompression, but will create three other threads for
+reading, writing, and check calculation, which can speed up decompression
+under some circumstances.  Parallel decompression can be turned off by
+specifying one process 
+(
+.B -dp 1
+or
+.B -tp 1
+).
+.PP
+Compressed files can be restored to their original form using
+.I pigz -d
+or
+.I unpigz.
+
+.SH OPTIONS
+.TP
+.B -# --fast --best
+Regulate the speed of compression using the specified digit
+.IR # ,
+where
+.B \-1
+or
+.B \-\-fast
+indicates the fastest compression method (less compression)
+and
+.B \-9
+or
+.B \-\-best
+indicates the slowest compression method (best compression).
+Level 0 is no compression.
+.TP
+.B -b --blocksize mmm
+Set compression block size to mmmK (default 128KiB).
+.TP
+.B -c --stdout --to-stdout
+Write all processed output to stdout (won't delete).
+.TP
+.B -d --decompress --uncompress
+Decompress the compressed input.
+.TP
+.B -f --force
+Force overwrite, compress .gz, links, and to terminal.
+.TP
+.B -h --help
+Display a help screen and quit.
+.TP
+.B -i --independent
+Compress blocks independently for damage recovery.
+.TP
+.B -k --keep
+Do not delete original file after processing.
+.TP
+.B -K --zip
+Compress to PKWare zip (.zip) single entry format.
+.TP
+.B -l --list
+List the contents of the compressed input.
+.TP
+.B -L --license
+Display the
+.I pigz
+license and quit.
+.TP
+.B -n --no-name
+Do not store or restore file name in/from header.
+.TP
+.B -N --name
+Store/restore file name and mod time in/from header.
+.TP
+.B -p --processes n
+Allow up to n processes (default is the number of online processors)
+.TP
+.B -q --quiet --silent
+Print no messages, even on error.
+.TP
+.B -r --recursive
+Process the contents of all subdirectories.
+.TP
+.B -S --suffix .sss
+Use suffix .sss instead of .gz (for compression).
+.TP
+.B -t --test
+Test the integrity of the compressed input.
+.TP
+.B -T --no-time
+Do not store or restore mod time in/from header.
+.TP
+.B -v --verbose
+Provide more verbose output.
+.TP
+.B -V --version
+Show the version of pigz.
+.TP
+.B -z --zlib
+Compress to zlib (.zz) instead of gzip format.
+.SH "COPYRIGHT NOTICE"
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the author be held liable for any damages
+arising from the use of this software.
+.PP
+Copyright (C) 2007, 2008, 2009, 2010 Mark Adler <madler@alumni.caltech.edu>
diff --git a/pigz/pigz.c b/pigz/pigz.c
new file mode 100644
index 0000000..97e6faa
--- /dev/null
+++ b/pigz/pigz.c
@@ -0,0 +1,3128 @@
+/* pigz.c -- parallel implementation of gzip
+ * Copyright (C) 2007, 2008, 2009, 2010 Mark Adler
+ * Version 2.1.6  17 Jan 2010  Mark Adler
+ */
+
+/*
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the author be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+
+  Mark Adler
+  madler@alumni.caltech.edu
+
+  Mark accepts donations for providing this software.  Donations are not
+  required or expected.  Any amount that you feel is appropriate would be
+  appreciated.  You can use this link:
+
+  https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=536055
+
+ */
+
+/* Version history:
+   1.0    17 Jan 2007  First version, pipe only
+   1.1    28 Jan 2007  Avoid void * arithmetic (some compilers don't get that)
+                       Add note about requiring zlib 1.2.3
+                       Allow compression level 0 (no compression)
+                       Completely rewrite parallelism -- add a write thread
+                       Use deflateSetDictionary() to make use of history
+                       Tune argument defaults to best performance on four cores
+   1.2.1   1 Feb 2007  Add long command line options, add all gzip options
+                       Add debugging options
+   1.2.2  19 Feb 2007  Add list (--list) function
+                       Process file names on command line, write .gz output
+                       Write name and time in gzip header, set output file time
+                       Implement all command line options except --recursive
+                       Add --keep option to prevent deleting input files
+                       Add thread tracing information with -vv used
+                       Copy crc32_combine() from zlib (possible thread issue)
+   1.3    25 Feb 2007  Implement --recursive
+                       Expand help to show all options
+                       Show help if no arguments or output piping are provided
+                       Process options in GZIP environment variable
+                       Add progress indicator to write thread if --verbose
+   1.4     4 Mar 2007  Add --independent to facilitate damaged file recovery
+                       Reallocate jobs for new --blocksize or --processes
+                       Do not delete original if writing to stdout
+                       Allow --processes 1, which does no threading
+                       Add NOTHREAD define to compile without threads
+                       Incorporate license text from zlib in source code
+   1.5    25 Mar 2007  Reinitialize jobs for new compression level
+                       Copy attributes and owner from input file to output file
+                       Add decompression and testing
+                       Add -lt (or -ltv) to show all entries and proper lengths
+                       Add decompression, testing, listing of LZW (.Z) files
+                       Only generate and show trace log if DEBUG defined
+                       Take "-" argument to mean read file from stdin
+   1.6    30 Mar 2007  Add zlib stream compression (--zlib), and decompression
+   1.7    29 Apr 2007  Decompress first entry of a zip file (if deflated)
+                       Avoid empty deflate blocks at end of deflate stream
+                       Show zlib check value (Adler-32) when listing
+                       Don't complain when decompressing empty file
+                       Warn about trailing junk for gzip and zlib streams
+                       Make listings consistent, ignore gzip extra flags
+                       Add zip stream compression (--zip)
+   1.8    13 May 2007  Document --zip option in help output
+   2.0    19 Oct 2008  Complete rewrite of thread usage and synchronization
+                       Use polling threads and a pool of memory buffers
+                       Remove direct pthread library use, hide in yarn.c
+   2.0.1  20 Oct 2008  Check version of zlib at compile time, need >= 1.2.3
+   2.1    24 Oct 2008  Decompress with read, write, inflate, and check threads
+                       Remove spurious use of ctime_r(), ctime() more portable
+                       Change application of job->calc lock to be a semaphore
+                       Detect size of off_t at run time to select %lu vs. %llu
+                       #define large file support macro even if not __linux__
+                       Remove _LARGEFILE64_SOURCE, _FILE_OFFSET_BITS is enough
+                       Detect file-too-large error and report, blame build
+                       Replace check combination routines with those from zlib
+   2.1.1  28 Oct 2008  Fix a leak for files with an integer number of blocks
+                       Update for yarn 1.1 (yarn_prefix and yarn_abort)
+   2.1.2  30 Oct 2008  Work around use of beta zlib in production systems
+   2.1.3   8 Nov 2008  Don't use zlib combination routines, put back in pigz
+   2.1.4   9 Nov 2008  Fix bug when decompressing very short files
+   2.1.5  20 Jul 2009  Added 2008, 2009 to --license statement
+                       Allow numeric parameter immediately after -p or -b
+                       Enforce parameter after -p, -b, -s, before other options
+                       Enforce numeric parameters to have only numeric digits
+                       Try to determine the number of processors for -p default
+                       Fix --suffix short option to be -S to match gzip [Bloch]
+                       Decompress if executable named "unpigz" [Amundsen]
+                       Add a little bit of testing to Makefile
+   2.1.6  17 Jan 2010  Added pigz.spec to distribution for RPM systems [Brown]
+                       Avoid some compiler warnings
+                       Process symbolic links if piping to stdout [Hoffstätte]
+                       Decompress if executable named "gunzip" [Hoffstätte]
+                       Allow ".tgz" suffix [Chernookiy]
+                       Fix adler32 comparison on .zz files
+ */
+
+#define VERSION "pigz 2.1.6\n"
+
+/* To-do:
+    - add --rsyncable (or -R) [use my own algorithm, set min/max block size]
+    - make source portable for Windows, VMS, etc. (see gzip source code)
+    - make build portable (currently good for Unixish)
+    - add bzip2 decompression
+ */
+
+/*
+   pigz compresses using threads to make use of multiple processors and cores.
+   The input is broken up into 128 KB chunks with each compressed in parallel.
+   The individual check value for each chunk is also calculated in parallel.
+   The compressed data is written in order to the output, and a combined check
+   value is calculated from the individual check values.
+
+   The compressed data format generated is in the gzip, zlib, or single-entry
+   zip format using the deflate compression method.  The compression produces
+   partial raw deflate streams which are concatenated by a single write thread
+   and wrapped with the appropriate header and trailer, where the trailer
+   contains the combined check value.
+
+   Each partial raw deflate stream is terminated by an empty stored block
+   (using the Z_SYNC_FLUSH option of zlib), in order to end that partial bit
+   stream at a byte boundary.  That allows the partial streams to be
+   concatenated simply as sequences of bytes.  This adds a very small four to
+   five byte overhead to the output for each input chunk.
+
+   The default input block size is 128K, but can be changed with the -b option.
+   The number of compress threads is set by default to 8, which can be changed
+   using the -p option.  Specifying -p 1 avoids the use of threads entirely.
+   pigz will try to determine the number of processors in the machine, in which
+   case if that number is two or greater, pigz will use that as the default for
+   -p instead of 8.
+
+   The input blocks, while compressed independently, have the last 32K of the
+   previous block loaded as a preset dictionary to preserve the compression
+   effectiveness of deflating in a single thread.  This can be turned off using
+   the --independent or -i option, so that the blocks can be decompressed
+   independently for partial error recovery or for random access.
+
+   Decompression can't be parallelized, at least not without specially prepared
+   deflate streams for that purpose.  As a result, pigz uses a single thread
+   (the main thread) for decompression, but will create three other threads for
+   reading, writing, and check calculation, which can speed up decompression
+   under some circumstances.  Parallel decompression can be turned off by
+   specifying one process (-dp 1 or -tp 1).
+
+   pigz requires zlib 1.2.1 or later to allow setting the dictionary when doing
+   raw deflate.  Since zlib 1.2.3 corrects security vulnerabilities in zlib
+   version 1.2.1 and 1.2.2, conditionals check for zlib 1.2.3 or later during
+   the compilation of pigz.c.  zlib 1.2.4 includes some improvements to
+   Z_FULL_FLUSH and deflateSetDictionary() that permit identical output for
+   pigz with and without threads, which is not possible with zlib 1.2.3.  This
+   may be important for uses of pigz -R where small changes in the contents
+   should result in small changes in the archive for rsync.  Note that due to
+   the details of how the lower levels of compression result in greater speed,
+   compression level 3 and below does not permit identical pigz output with
+   and without threads.
+
+   pigz uses the POSIX pthread library for thread control and communication,
+   through the yarn.h interface to yarn.c.  yarn.c can be replaced with
+   equivalent implementations using other thread libraries.  pigz can be
+   compiled with NOTHREAD #defined to not use threads at all (in which case
+   pigz will not be able to live up to the "parallel" in its name).
+ */
+
+/*
+   Details of parallel compression implementation:
+
+   When doing parallel compression, pigz uses the main thread to read the input
+   in 'size' sized chunks (see -b), and puts those in a compression job list,
+   each with a sequence number to keep track of the ordering.  If it is not the
+   first chunk, then that job also points to the previous input buffer, from
+   which the last 32K will be used as a dictionary (unless -i is specified).
+   This sets a lower limit of 32K on 'size'.
+
+   pigz launches up to 'procs' compression threads (see -p).  Each compression
+   thread continues to look for jobs in the compression list and perform those
+   jobs until instructed to return.  When a job is pulled, the dictionary, if
+   provided, will be loaded into the deflate engine and then that input buffer
+   is dropped for reuse.  Then the input data is compressed into an output
+   buffer sized to assure that it can contain maximally expanded deflate data.
+   The job is then put into the write job list, sorted by the sequence number.
+   The compress thread however continues to calculate the check value on the
+   input data, either a CRC-32 or Adler-32, possibly in parallel with the write
+   thread writing the output data.  Once that's done, the compress thread drops
+   the input buffer and also releases the lock on the check value so that the
+   write thread can combine it with the previous check values.  The compress
+   thread has then completed that job, and goes to look for another.
+
+   All of the compress threads are left running and waiting even after the last
+   chunk is processed, so that they can support the next input to be compressed
+   (more than one input file on the command line).  Once pigz is done, it will
+   call all the compress threads home (that'll do pig, that'll do).
+
+   Before starting to read the input, the main thread launches the write thread
+   so that it is ready pick up jobs immediately.  The compress thread puts the
+   write jobs in the list in sequence sorted order, so that the first job in
+   the list is always has the lowest sequence number.  The write thread waits
+   for the next write job in sequence, and then gets that job.  The job still
+   holds its input buffer, from which the write thread gets the input buffer
+   length for use in check value combination.  Then the write thread drops that
+   input buffer to allow its reuse.  Holding on to the input buffer until the
+   write thread starts also has the benefit that the read and compress threads
+   can't get way ahead of the write thread and build up a large backlog of
+   unwritten compressed data.  The write thread will write the compressed data,
+   drop the output buffer, and then wait for the check value to be unlocked
+   by the compress thread.  Then the write thread combines the check value for
+   this chunk with the total check value for eventual use in the trailer.  If
+   this is not the last chunk, the write thread then goes back to look for the
+   next output chunk in sequence.  After the last chunk, the write thread
+   returns and joins the main thread.  Unlike the compress threads, a new write
+   thread is launched for each input stream.  The write thread writes the
+   appropriate header and trailer around the compressed data.
+
+   The input and output buffers are reused through their collection in pools.
+   Each buffer has a use count, which when decremented to zero returns the
+   buffer to the respective pool.  Each input buffer has up to three parallel
+   uses: as the input for compression, as the data for the check value
+   calculation, and as a dictionary for compression.  Each output buffer has
+   only one use, which is as the output of compression followed serially as
+   data to be written.  The input pool is limited in the number of buffers, so
+   that reading does not get way ahead of compression and eat up memory with
+   more input than can be used.  The limit is approximately two times the
+   number of compression threads.  In the case that reading is fast as compared
+   to compression, that number allows a second set of buffers to be read while
+   the first set of compressions are being performed.  The number of output
+   buffers is not directly limited, but is indirectly limited by the release of
+   input buffers to the same number.
+ */
+
+/* use large file functions if available */
+#define _FILE_OFFSET_BITS 64
+
+/* included headers and what is expected from each */
+#include <stdio.h>      /* fflush(), fprintf(), fputs(), getchar(), putc(), */
+                        /* puts(), printf(), vasprintf(), stderr, EOF, NULL,
+                           SEEK_END, size_t, off_t */
+#include <stdlib.h>     /* exit(), malloc(), free(), realloc(), atol(), */
+                        /* atoi(), getenv() */
+#include <stdarg.h>     /* va_start(), va_end(), va_list */
+#include <string.h>     /* memset(), memchr(), memcpy(), strcmp(), strcpy() */
+                        /* strncpy(), strlen(), strcat(), strrchr() */
+#include <errno.h>      /* errno, EEXIST */
+#include <assert.h>     /* assert() */
+#include <time.h>       /* ctime(), time(), time_t, mktime() */
+#include <signal.h>     /* signal(), SIGINT */
+#include <sys/types.h>  /* ssize_t */
+#include <sys/stat.h>   /* chmod(), stat(), fstat(), lstat(), struct stat, */
+                        /* S_IFDIR, S_IFLNK, S_IFMT, S_IFREG */
+#include <sys/time.h>   /* utimes(), gettimeofday(), struct timeval */
+#include <unistd.h>     /* unlink(), _exit(), read(), write(), close(), */
+                        /* lseek(), isatty(), chown() */
+#include <fcntl.h>      /* open(), O_CREAT, O_EXCL, O_RDONLY, O_TRUNC, */
+                        /* O_WRONLY */
+#include <dirent.h>     /* opendir(), readdir(), closedir(), DIR, */
+                        /* struct dirent */
+#include <limits.h>     /* PATH_MAX */
+
+#include "zlib.h"       /* deflateInit2(), deflateReset(), deflate(), */
+                        /* deflateEnd(), deflateSetDictionary(), crc32(),
+                           inflateBackInit(), inflateBack(), inflateBackEnd(),
+                           Z_DEFAULT_COMPRESSION, Z_DEFAULT_STRATEGY,
+                           Z_DEFLATED, Z_NO_FLUSH, Z_NULL, Z_OK,
+                           Z_SYNC_FLUSH, z_stream */
+#if !defined(ZLIB_VERNUM) || ZLIB_VERNUM < 0x1230
+#  error Need zlib version 1.2.3 or later
+#endif
+
+#ifndef NOTHREAD
+#  include "yarn.h"     /* thread, launch(), join(), join_all(), */
+                        /* lock, new_lock(), possess(), twist(), wait_for(),
+                           release(), peek_lock(), free_lock(), yarn_name */
+#endif
+
+/* for local functions and globals */
+#define local static
+
+/* prevent end-of-line conversions on MSDOSish operating systems */
+#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
+#  include <io.h>       /* setmode(), O_BINARY */
+#  define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
+#else
+#  define SET_BINARY_MODE(fd)
+#endif
+
+/* release an allocated pointer, if allocated, and mark as unallocated */
+#define RELEASE(ptr) \
+    do { \
+        if ((ptr) != NULL) { \
+            free(ptr); \
+            ptr = NULL; \
+        } \
+    } while (0)
+
+/* globals (modified by main thread only when it's the only thread) */
+local int ind;              /* input file descriptor */
+local int outd;             /* output file descriptor */
+local char in[PATH_MAX+1];  /* input file name (accommodate recursion) */
+local char *out = NULL;     /* output file name (allocated if not NULL) */
+local int verbosity;        /* 0 = quiet, 1 = normal, 2 = verbose, 3 = trace */
+local int headis;           /* 1 to store name, 2 to store date, 3 both */
+local int pipeout;          /* write output to stdout even if file */
+local int keep;             /* true to prevent deletion of input file */
+local int force;            /* true to overwrite, compress links */
+local int form;             /* gzip = 0, zlib = 1, zip = 2 or 3 */
+local int recurse;          /* true to dive down into directory structure */
+local char *sufx;           /* suffix to use (".gz" or user supplied) */
+local char *name;           /* name for gzip header */
+local time_t mtime;         /* time stamp from input file for gzip header */
+local int list;             /* true to list files instead of compress */
+local int first = 1;        /* true if we need to print listing header */
+local int decode;           /* 0 to compress, 1 to decompress, 2 to test */
+local int level;            /* compression level */
+local int rsync;            /* true for rsync blocking */
+local int procs;            /* maximum number of compression threads (>= 1) */
+local int dict;             /* true to initialize dictionary in each thread */
+local size_t size;          /* uncompressed input size per thread (>= 32K) */
+
+/* saved gzip/zip header data for decompression, testing, and listing */
+local time_t stamp;                 /* time stamp from gzip header */
+local char *hname = NULL;           /* name from header (allocated) */
+local unsigned long zip_crc;        /* local header crc */
+local unsigned long zip_clen;       /* local header compressed length */
+local unsigned long zip_ulen;       /* local header uncompressed length */
+
+/* exit with error, delete output file if in the middle of writing it */
+local int bail(char *why, char *what)
+{
+    if (outd != -1 && out != NULL)
+        unlink(out);
+    if (verbosity > 0)
+        fprintf(stderr, "pigz abort: %s%s\n", why, what);
+    exit(1);
+    return 0;
+}
+
+#ifdef DEBUG
+
+/* starting time of day for tracing */
+local struct timeval start;
+
+/* trace log */
+local struct log {
+    struct timeval when;    /* time of entry */
+    char *msg;              /* message */
+    struct log *next;       /* next entry */
+} *log_head, **log_tail = NULL;
+#ifndef NOTHREAD
+  local lock *log_lock = NULL;
+#endif
+
+/* maximum log entry length */
+#define MAXMSG 256
+
+/* set up log (call from main thread before other threads launched) */
+local void log_init(void)
+{
+    if (log_tail == NULL) {
+#ifndef NOTHREAD
+        log_lock = new_lock(0);
+#endif
+        log_head = NULL;
+        log_tail = &log_head;
+    }
+}
+
+/* add entry to trace log */
+local void log_add(char *fmt, ...)
+{
+    struct timeval now;
+    struct log *me;
+    va_list ap;
+    char msg[MAXMSG];
+
+    gettimeofday(&now, NULL);
+    me = malloc(sizeof(struct log));
+    if (me == NULL)
+        bail("not enough memory", "");
+    me->when = now;
+    va_start(ap, fmt);
+    vsnprintf(msg, MAXMSG, fmt, ap);
+    va_end(ap);
+    me->msg = malloc(strlen(msg) + 1);
+    if (me->msg == NULL) {
+        free(me);
+        bail("not enough memory", "");
+    }
+    strcpy(me->msg, msg);
+    me->next = NULL;
+#ifndef NOTHREAD
+    assert(log_lock != NULL);
+    possess(log_lock);
+#endif
+    *log_tail = me;
+    log_tail = &(me->next);
+#ifndef NOTHREAD
+    twist(log_lock, BY, +1);
+#endif
+}
+
+/* pull entry from trace log and print it, return false if empty */
+local int log_show(void)
+{
+    struct log *me;
+    struct timeval diff;
+
+    if (log_tail == NULL)
+        return 0;
+#ifndef NOTHREAD
+    possess(log_lock);
+#endif
+    me = log_head;
+    if (me == NULL) {
+#ifndef NOTHREAD
+        release(log_lock);
+#endif
+        return 0;
+    }
+    log_head = me->next;
+    if (me->next == NULL)
+        log_tail = &log_head;
+#ifndef NOTHREAD
+    twist(log_lock, BY, -1);
+#endif
+    diff.tv_usec = me->when.tv_usec - start.tv_usec;
+    diff.tv_sec = me->when.tv_sec - start.tv_sec;
+    if (diff.tv_usec < 0) {
+        diff.tv_usec += 1000000L;
+        diff.tv_sec--;
+    }
+    fprintf(stderr, "trace %ld.%06ld %s\n",
+            (long)diff.tv_sec, (long)diff.tv_usec, me->msg);
+    fflush(stderr);
+    free(me->msg);
+    free(me);
+    return 1;
+}
+
+/* release log resources (need to do log_init() to use again) */
+local void log_free(void)
+{
+    struct log *me;
+
+    if (log_tail != NULL) {
+#ifndef NOTHREAD
+        possess(log_lock);
+#endif
+        while ((me = log_head) != NULL) {
+            log_head = me->next;
+            free(me->msg);
+            free(me);
+        }
+#ifndef NOTHREAD
+        twist(log_lock, TO, 0);
+        free_lock(log_lock);
+        log_lock = NULL;
+#endif
+        log_tail = NULL;
+    }
+}
+
+/* show entries until no more, free log */
+local void log_dump(void)
+{
+    if (log_tail == NULL)
+        return;
+    while (log_show())
+        ;
+    log_free();
+}
+
+/* debugging macro */
+#define Trace(x) \
+    do { \
+        if (verbosity > 2) { \
+            log_add x; \
+        } \
+    } while (0)
+
+#else /* !DEBUG */
+
+#define log_dump()
+#define Trace(x)
+
+#endif
+
+/* read up to len bytes into buf, repeating read() calls as needed */
+local size_t readn(int desc, unsigned char *buf, size_t len)
+{
+    ssize_t ret;
+    size_t got;
+
+    got = 0;
+    while (len) {
+        ret = read(desc, buf, len);
+        if (ret < 0)
+            bail("read error on ", in);
+        if (ret == 0)
+            break;
+        buf += ret;
+        len -= ret;
+        got += ret;
+    }
+    return got;
+}
+
+/* write len bytes, repeating write() calls as needed */
+local void writen(int desc, unsigned char *buf, size_t len)
+{
+    ssize_t ret;
+
+    while (len) {
+        ret = write(desc, buf, len);
+        if (ret < 1)
+            fprintf(stderr, "write error code %d\n", errno);
+        if (ret < 1)
+            bail("write error on ", out);
+        buf += ret;
+        len -= ret;
+    }
+}
+
+/* sliding dictionary size for deflate */
+#define DICT 32768U
+
+/* largest power of 2 that fits in an unsigned int -- used to limit requests
+   to zlib functions that use unsigned int lengths */
+#define MAX ((((unsigned)0 - 1) >> 1) + 1)
+
+/* convert Unix time to MS-DOS date and time, assuming current timezone
+   (you got a better idea?) */
+local unsigned long time2dos(time_t t)
+{
+    struct tm *tm;
+    unsigned long dos;
+
+    if (t == 0)
+        t = time(NULL);
+    tm = localtime(&t);
+    if (tm->tm_year < 80 || tm->tm_year > 207)
+        return 0;
+    dos = (tm->tm_year - 80) << 25;
+    dos += (tm->tm_mon + 1) << 21;
+    dos += tm->tm_mday << 16;
+    dos += tm->tm_hour << 11;
+    dos += tm->tm_min << 5;
+    dos += (tm->tm_sec + 1) >> 1;   /* round to double-seconds */
+    return dos;
+}
+
+/* put a 4-byte integer into a byte array in LSB order or MSB order */
+#define PUT2L(a,b) (*(a)=(b)&0xff,(a)[1]=(b)>>8)
+#define PUT4L(a,b) (PUT2L(a,(b)&0xffff),PUT2L((a)+2,(b)>>16))
+#define PUT4M(a,b) (*(a)=(b)>>24,(a)[1]=(b)>>16,(a)[2]=(b)>>8,(a)[3]=(b))
+
+/* write a gzip, zlib, or zip header using the information in the globals */
+local unsigned long put_header(void)
+{
+    unsigned long len;
+    unsigned char head[30];
+
+    if (form > 1) {                 /* zip */
+        /* write local header */
+        PUT4L(head, 0x04034b50UL);  /* local header signature */
+        PUT2L(head + 4, 20);        /* version needed to extract (2.0) */
+        PUT2L(head + 6, 8);         /* flags: data descriptor follows data */
+        PUT2L(head + 8, 8);         /* deflate */
+        PUT4L(head + 10, time2dos(mtime));
+        PUT4L(head + 14, 0);        /* crc (not here) */
+        PUT4L(head + 18, 0);        /* compressed length (not here) */
+        PUT4L(head + 22, 0);        /* uncompressed length (not here) */
+        PUT2L(head + 26, name == NULL ? 1 : strlen(name));  /* name length */
+        PUT2L(head + 28, 9);        /* length of extra field (see below) */
+        writen(outd, head, 30);     /* write local header */
+        len = 30;
+
+        /* write file name (use "-" for stdin) */
+        if (name == NULL)
+            writen(outd, (unsigned char *)"-", 1);
+        else
+            writen(outd, (unsigned char *)name, strlen(name));
+        len += name == NULL ? 1 : strlen(name);
+
+        /* write extended timestamp extra field block (9 bytes) */
+        PUT2L(head, 0x5455);        /* extended timestamp signature */
+        PUT2L(head + 2, 5);         /* number of data bytes in this block */
+        head[4] = 1;                /* flag presence of mod time */
+        PUT4L(head + 5, mtime);     /* mod time */
+        writen(outd, head, 9);      /* write extra field block */
+        len += 9;
+    }
+    else if (form) {                /* zlib */
+        head[0] = 0x78;             /* deflate, 32K window */
+        head[1] = (level == 9 ? 3 : (level == 1 ? 0 :
+            (level >= 6 || level == Z_DEFAULT_COMPRESSION ? 1 :  2))) << 6;
+        head[1] += 31 - (((head[0] << 8) + head[1]) % 31);
+        writen(outd, head, 2);
+        len = 2;
+    }
+    else {                          /* gzip */
+        head[0] = 31;
+        head[1] = 139;
+        head[2] = 8;                /* deflate */
+        head[3] = name != NULL ? 8 : 0;
+        PUT4L(head + 4, mtime);
+        head[8] = level == 9 ? 2 : (level == 1 ? 4 : 0);
+        head[9] = 3;                /* unix */
+        writen(outd, head, 10);
+        len = 10;
+        if (name != NULL)
+            writen(outd, (unsigned char *)name, strlen(name) + 1);
+        if (name != NULL)
+            len += strlen(name) + 1;
+    }
+    return len;
+}
+
+/* write a gzip, zlib, or zip trailer */
+local void put_trailer(unsigned long ulen, unsigned long clen,
+                       unsigned long check, unsigned long head)
+{
+    unsigned char tail[46];
+
+    if (form > 1) {                 /* zip */
+        unsigned long cent;
+
+        /* write data descriptor (as promised in local header) */
+        PUT4L(tail, check);
+        PUT4L(tail + 4, clen);
+        PUT4L(tail + 8, ulen);
+        writen(outd, tail, 12);
+
+        /* write central file header */
+        PUT4L(tail, 0x02014b50UL);  /* central header signature */
+        tail[4] = 63;               /* obeyed version 6.3 of the zip spec */
+        tail[5] = 255;              /* ignore external attributes */
+        PUT2L(tail + 6, 20);        /* version needed to extract (2.0) */
+        PUT2L(tail + 8, 8);         /* data descriptor is present */
+        PUT2L(tail + 10, 8);        /* deflate */
+        PUT4L(tail + 12, time2dos(mtime));
+        PUT4L(tail + 16, check);    /* crc */
+        PUT4L(tail + 20, clen);     /* compressed length */
+        PUT4L(tail + 24, ulen);     /* uncompressed length */
+        PUT2L(tail + 28, name == NULL ? 1 : strlen(name));  /* name length */
+        PUT2L(tail + 30, 9);        /* length of extra field (see below) */
+        PUT2L(tail + 32, 0);        /* no file comment */
+        PUT2L(tail + 34, 0);        /* disk number 0 */
+        PUT2L(tail + 36, 0);        /* internal file attributes */
+        PUT4L(tail + 38, 0);        /* external file attributes (ignored) */
+        PUT4L(tail + 42, 0);        /* offset of local header */
+        writen(outd, tail, 46);     /* write central file header */
+        cent = 46;
+
+        /* write file name (use "-" for stdin) */
+        if (name == NULL)
+            writen(outd, (unsigned char *)"-", 1);
+        else
+            writen(outd, (unsigned char *)name, strlen(name));
+        cent += name == NULL ? 1 : strlen(name);
+
+        /* write extended timestamp extra field block (9 bytes) */
+        PUT2L(tail, 0x5455);        /* extended timestamp signature */
+        PUT2L(tail + 2, 5);         /* number of data bytes in this block */
+        tail[4] = 1;                /* flag presence of mod time */
+        PUT4L(tail + 5, mtime);     /* mod time */
+        writen(outd, tail, 9);      /* write extra field block */
+        cent += 9;
+
+        /* write end of central directory record */
+        PUT4L(tail, 0x06054b50UL);  /* end of central directory signature */
+        PUT2L(tail + 4, 0);         /* number of this disk */
+        PUT2L(tail + 6, 0);         /* disk with start of central directory */
+        PUT2L(tail + 8, 1);         /* number of entries on this disk */
+        PUT2L(tail + 10, 1);        /* total number of entries */
+        PUT4L(tail + 12, cent);     /* size of central directory */
+        PUT4L(tail + 16, head + clen + 12); /* offset of central directory */
+        PUT2L(tail + 20, 0);        /* no zip file comment */
+        writen(outd, tail, 22);     /* write end of central directory record */
+    }
+    else if (form) {                /* zlib */
+        PUT4M(tail, check);
+        writen(outd, tail, 4);
+    }
+    else {                          /* gzip */
+        PUT4L(tail, check);
+        PUT4L(tail + 4, ulen);
+        writen(outd, tail, 8);
+    }
+}
+
+/* compute check value depending on format */
+#define CHECK(a,b,c) (form == 1 ? adler32(a,b,c) : crc32(a,b,c))
+
+#ifndef NOTHREAD
+/* -- threaded portions of pigz -- */
+
+/* -- check value combination routines for parallel calculation -- */
+
+#define COMB(a,b,c) (form == 1 ? adler32_comb(a,b,c) : crc32_comb(a,b,c))
+/* combine two crc-32's or two adler-32's (copied from zlib 1.2.3 so that pigz
+   can be compatible with older versions of zlib) */
+
+/* we copy the combination routines from zlib here, in order to avoid
+   linkage issues with the zlib 1.2.3 builds on Sun, Ubuntu, and others */
+
+local unsigned long gf2_matrix_times(unsigned long *mat, unsigned long vec)
+{
+    unsigned long sum;
+
+    sum = 0;
+    while (vec) {
+        if (vec & 1)
+            sum ^= *mat;
+        vec >>= 1;
+        mat++;
+    }
+    return sum;
+}
+
+local void gf2_matrix_square(unsigned long *square, unsigned long *mat)
+{
+    int n;
+
+    for (n = 0; n < 32; n++)
+        square[n] = gf2_matrix_times(mat, mat[n]);
+}
+
+local unsigned long crc32_comb(unsigned long crc1, unsigned long crc2,
+                               size_t len2)
+{
+    int n;
+    unsigned long row;
+    unsigned long even[32];     /* even-power-of-two zeros operator */
+    unsigned long odd[32];      /* odd-power-of-two zeros operator */
+
+    /* degenerate case */
+    if (len2 == 0)
+        return crc1;
+
+    /* put operator for one zero bit in odd */
+    odd[0] = 0xedb88320UL;          /* CRC-32 polynomial */
+    row = 1;
+    for (n = 1; n < 32; n++) {
+        odd[n] = row;
+        row <<= 1;
+    }
+
+    /* put operator for two zero bits in even */
+    gf2_matrix_square(even, odd);
+
+    /* put operator for four zero bits in odd */
+    gf2_matrix_square(odd, even);
+
+    /* apply len2 zeros to crc1 (first square will put the operator for one
+       zero byte, eight zero bits, in even) */
+    do {
+        /* apply zeros operator for this bit of len2 */
+        gf2_matrix_square(even, odd);
+        if (len2 & 1)
+            crc1 = gf2_matrix_times(even, crc1);
+        len2 >>= 1;
+
+        /* if no more bits set, then done */
+        if (len2 == 0)
+            break;
+
+        /* another iteration of the loop with odd and even swapped */
+        gf2_matrix_square(odd, even);
+        if (len2 & 1)
+            crc1 = gf2_matrix_times(odd, crc1);
+        len2 >>= 1;
+
+        /* if no more bits set, then done */
+    } while (len2 != 0);
+
+    /* return combined crc */
+    crc1 ^= crc2;
+    return crc1;
+}
+
+#define BASE 65521U     /* largest prime smaller than 65536 */
+#define LOW16 0xffff    /* mask lower 16 bits */
+
+local unsigned long adler32_comb(unsigned long adler1, unsigned long adler2,
+                                 size_t len2)
+{
+    unsigned long sum1;
+    unsigned long sum2;
+    unsigned rem;
+
+    /* the derivation of this formula is left as an exercise for the reader */
+    rem = (unsigned)(len2 % BASE);
+    sum1 = adler1 & LOW16;
+    sum2 = (rem * sum1) % BASE;
+    sum1 += (adler2 & LOW16) + BASE - 1;
+    sum2 += ((adler1 >> 16) & LOW16) + ((adler2 >> 16) & LOW16) + BASE - rem;
+    if (sum1 >= BASE) sum1 -= BASE;
+    if (sum1 >= BASE) sum1 -= BASE;
+    if (sum2 >= (BASE << 1)) sum2 -= (BASE << 1);
+    if (sum2 >= BASE) sum2 -= BASE;
+    return sum1 | (sum2 << 16);
+}
+
+/* -- pool of spaces for buffer management -- */
+
+/* These routines manage a pool of spaces.  Each pool specifies a fixed size
+   buffer to be contained in each space.  Each space has a use count, which
+   when decremented to zero returns the space to the pool.  If a space is
+   requested from the pool and the pool is empty, a space is immediately
+   created unless a specified limit on the number of spaces has been reached.
+   Only if the limit is reached will it wait for a space to be returned to the
+   pool.  Each space knows what pool it belongs to, so that it can be returned.
+ */
+
+/* a space (one buffer for each space) */
+struct space {
+    lock *use;              /* use count -- return to pool when zero */
+    void *buf;              /* buffer of size pool->size */
+    size_t len;             /* for application usage */
+    struct pool *pool;      /* pool to return to */
+    struct space *next;     /* for pool linked list */
+};
+
+/* pool of spaces (one pool for each size needed) */
+struct pool {
+    lock *have;             /* unused spaces available, lock for list */
+    struct space *head;     /* linked list of available buffers */
+    size_t size;            /* size of all buffers in this pool */
+    int limit;              /* number of new spaces allowed, or -1 */
+    int made;               /* number of buffers made */
+};
+
+/* initialize a pool (pool structure itself provided, not allocated) -- the
+   limit is the maximum number of spaces in the pool, or -1 to indicate no
+   limit, i.e., to never wait for a buffer to return to the pool */
+local void new_pool(struct pool *pool, size_t size, int limit)
+{
+    pool->have = new_lock(0);
+    pool->head = NULL;
+    pool->size = size;
+    pool->limit = limit;
+    pool->made = 0;
+}
+
+/* get a space from a pool -- the use count is initially set to one, so there
+   is no need to call use_space() for the first use */
+local struct space *get_space(struct pool *pool)
+{
+    struct space *space;
+
+    /* if can't create any more, wait for a space to show up */
+    possess(pool->have);
+    if (pool->limit == 0)
+        wait_for(pool->have, NOT_TO_BE, 0);
+
+    /* if a space is available, pull it from the list and return it */
+    if (pool->head != NULL) {
+        space = pool->head;
+        possess(space->use);
+        pool->head = space->next;
+        twist(pool->have, BY, -1);      /* one less in pool */
+        twist(space->use, TO, 1);       /* initially one user */
+        return space;
+    }
+
+    /* nothing available, don't want to wait, make a new space */
+    assert(pool->limit != 0);
+    if (pool->limit > 0)
+        pool->limit--;
+    pool->made++;
+    release(pool->have);
+    space = malloc(sizeof(struct space));
+    if (space == NULL)
+        bail("not enough memory", "");
+    space->use = new_lock(1);           /* initially one user */
+    space->buf = malloc(pool->size);
+    if (space->buf == NULL)
+        bail("not enough memory", "");
+    space->pool = pool;                 /* remember the pool this belongs to */
+    return space;
+}
+
+/* increment the use count to require one more drop before returning this space
+   to the pool */
+local void use_space(struct space *space)
+{
+    possess(space->use);
+    twist(space->use, BY, +1);
+}
+
+/* drop a space, returning it to the pool if the use count is zero */
+local void drop_space(struct space *space)
+{
+    int use;
+    struct pool *pool;
+
+    possess(space->use);
+    use = peek_lock(space->use);
+    assert(use != 0);
+    if (use == 1) {
+        pool = space->pool;
+        possess(pool->have);
+        space->next = pool->head;
+        pool->head = space;
+        twist(pool->have, BY, +1);
+    }
+    twist(space->use, BY, -1);
+}
+
+/* free the memory and lock resources of a pool -- return number of spaces for
+   debugging and resource usage measurement */
+local int free_pool(struct pool *pool)
+{
+    int count;
+    struct space *space;
+
+    possess(pool->have);
+    count = 0;
+    while ((space = pool->head) != NULL) {
+        pool->head = space->next;
+        free(space->buf);
+        free_lock(space->use);
+        free(space);
+        count++;
+    }
+    release(pool->have);
+    free_lock(pool->have);
+    assert(count == pool->made);
+    return count;
+}
+
+/* input and output buffer pools */
+local struct pool in_pool;
+local struct pool out_pool;
+
+/* -- parallel compression -- */
+
+/* compress or write job (passed from compress list to write list) -- if seq is
+   equal to -1, compress_thread is instructed to return; if more is false then
+   this is the last chunk, which after writing tells write_thread to return */
+struct job {
+    long seq;                   /* sequence number */
+    int more;                   /* true if this is not the last chunk */
+    struct space *in;           /* input data to compress */
+    struct space *out;          /* dictionary or resulting compressed data */
+    unsigned long check;        /* check value for input data */
+    lock *calc;                 /* released when check calculation complete */
+    struct job *next;           /* next job in the list (either list) */
+};
+
+/* list of compress jobs (with tail for appending to list) */
+local lock *compress_have = NULL;   /* number of compress jobs waiting */
+local struct job *compress_head, **compress_tail;
+
+/* list of write jobs */
+local lock *write_first;            /* lowest sequence number in list */
+local struct job *write_head;
+
+/* number of compression threads running */
+local int cthreads = 0;
+
+/* write thread if running */
+local thread *writeth = NULL;
+
+/* setup job lists (call from main thread) */
+local void setup_jobs(void)
+{
+    /* set up only if not already set up*/
+    if (compress_have != NULL)
+        return;
+
+    /* allocate locks and initialize lists */
+    compress_have = new_lock(0);
+    compress_head = NULL;
+    compress_tail = &compress_head;
+    write_first = new_lock(-1);
+    write_head = NULL;
+
+    /* initialize buffer pools */
+    new_pool(&in_pool, size, (procs << 1) + 2);
+    new_pool(&out_pool, size + (size >> 11) + 10, -1);
+}
+
+/* command the compress threads to all return, then join them all (call from
+   main thread), free all the thread-related resources */
+local void finish_jobs(void)
+{
+    struct job job;
+    int caught;
+
+    /* only do this once */
+    if (compress_have == NULL)
+        return;
+
+    /* command all of the extant compress threads to return */
+    possess(compress_have);
+    job.seq = -1;
+    job.next = NULL;
+    compress_head = &job;
+    compress_tail = &(job.next);
+    twist(compress_have, BY, +1);       /* will wake them all up */
+
+    /* join all of the compress threads, verify they all came back */
+    caught = join_all();
+    Trace(("-- joined %d compress threads", caught));
+    assert(caught == cthreads);
+    cthreads = 0;
+
+    /* free the resources */
+    caught = free_pool(&out_pool);
+    Trace(("-- freed %d output buffers", caught));
+    caught = free_pool(&in_pool);
+    Trace(("-- freed %d input buffers", caught));
+    free_lock(write_first);
+    free_lock(compress_have);
+    compress_have = NULL;
+}
+
+/* get the next compression job from the head of the list, compress and compute
+   the check value on the input, and put a job in the write list with the
+   results -- keep looking for more jobs, returning when a job is found with a
+   sequence number of -1 (leave that job in the list for other incarnations to
+   find) */
+local void compress_thread(void *dummy)
+{
+    struct job *job;                /* job pulled and working on */ 
+    struct job *here, **prior;      /* pointers for inserting in write list */ 
+    unsigned long check;            /* check value of input */
+    unsigned char *next;            /* pointer for check value data */
+    size_t len;                     /* remaining bytes to compress/check */
+    z_stream strm;                  /* deflate stream */
+
+    (void)dummy;
+
+    /* initialize the deflate stream for this thread */
+    strm.zfree = Z_NULL;
+    strm.zalloc = Z_NULL;
+    strm.opaque = Z_NULL;
+    if (deflateInit2(&strm, level, Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY) !=
+            Z_OK)
+        bail("not enough memory", "");
+
+    /* keep looking for work */
+    for (;;) {
+        /* get a job (like I tell my son) */
+        possess(compress_have);
+        wait_for(compress_have, NOT_TO_BE, 0);
+        job = compress_head;
+        assert(job != NULL);
+        if (job->seq == -1)
+            break;
+        compress_head = job->next;
+        if (job->next == NULL)
+            compress_tail = &compress_head;
+        twist(compress_have, BY, -1);
+
+        /* got a job -- initialize and set the compression level (note that if
+           deflateParams() is called immediately after deflateReset(), there is
+           no need to initialize the input/output for the stream) */
+        Trace(("-- compressing #%ld", job->seq));
+        (void)deflateReset(&strm);
+        (void)deflateParams(&strm, level, Z_DEFAULT_STRATEGY);
+
+        /* set dictionary if provided, release that input buffer (only provided
+           if dict is true and if this is not the first work unit) -- the
+           amount of data in the buffer is assured to be >= DICT */
+        if (job->out != NULL) {
+            len = job->out->len;
+            deflateSetDictionary(&strm,
+                (unsigned char *)(job->out->buf) + (len - DICT), DICT);
+            drop_space(job->out);
+        }
+
+        /* set up input and output (the output size is assured to be big enough
+           for the worst case expansion of the input buffer size, plus five
+           bytes for the terminating stored block) */
+        job->out = get_space(&out_pool);
+        strm.next_in = job->in->buf;
+        strm.next_out = job->out->buf;
+
+        /* run MAX-sized amounts of input through deflate -- this loop is
+           needed for those cases where the integer type is smaller than the
+           size_t type, or when len is close to the limit of the size_t type */
+        len = job->in->len;
+        while (len > MAX) {
+            strm.avail_in = MAX;
+            strm.avail_out = (unsigned)-1;
+            (void)deflate(&strm, Z_NO_FLUSH);
+            assert(strm.avail_in == 0 && strm.avail_out != 0);
+            len -= MAX;
+        }
+
+        /* run the last piece through deflate -- terminate with a sync marker,
+           or finish deflate stream if this is the last block */
+        strm.avail_in = (unsigned)len;
+        strm.avail_out = (unsigned)-1;
+        (void)deflate(&strm, job->more ? Z_SYNC_FLUSH :  Z_FINISH);
+        assert(strm.avail_in == 0 && strm.avail_out != 0);
+        job->out->len = strm.next_out - (unsigned char *)(job->out->buf);
+        Trace(("-- compressed #%ld%s", job->seq, job->more ? "" : " (last)"));
+
+        /* reserve input buffer until check value has been calculated */
+        use_space(job->in);
+
+        /* insert write job in list in sorted order, alert write thread */
+        possess(write_first);
+        prior = &write_head;
+        while ((here = *prior) != NULL) {
+            if (here->seq > job->seq)
+                break;
+            prior = &(here->next);
+        }
+        job->next = here;
+        *prior = job;
+        twist(write_first, TO, write_head->seq);
+
+        /* calculate the check value in parallel with writing, alert the write
+           thread that the calculation is complete, and drop this usage of the
+           input buffer */
+        len = job->in->len;
+        next = job->in->buf;
+        check = CHECK(0L, Z_NULL, 0);
+        while (len > MAX) {
+            check = CHECK(check, next, MAX);
+            len -= MAX;
+            next += MAX;
+        }
+        check = CHECK(check, next, (unsigned)len);
+        drop_space(job->in);
+        job->check = check;
+        possess(job->calc);
+        twist(job->calc, TO, 1);
+        Trace(("-- checked #%ld%s", job->seq, job->more ? "" : " (last)"));
+
+        /* done with that one -- go find another job */
+    }
+
+    /* found job with seq == -1 -- free deflate memory and return to join */
+    release(compress_have);
+    deflateEnd(&strm);
+}
+
+/* collect the write jobs off of the list in sequence order and write out the
+   compressed data until the last chunk is written -- also write the header and
+   trailer and combine the individual check values of the input buffers */
+local void write_thread(void *dummy)
+{
+    long seq;                       /* next sequence number looking for */
+    struct job *job;                /* job pulled and working on */
+    size_t len;                     /* input length */
+    int more;                       /* true if more chunks to write */
+    unsigned long head;             /* header length */
+    unsigned long ulen;             /* total uncompressed size (overflow ok) */
+    unsigned long clen;             /* total compressed size (overflow ok) */
+    unsigned long check;            /* check value of uncompressed data */
+
+    (void)dummy;
+
+    /* build and write header */
+    Trace(("-- write thread running"));
+    head = put_header();
+
+    /* process output of compress threads until end of input */    
+    ulen = clen = 0;
+    check = CHECK(0L, Z_NULL, 0);
+    seq = 0;
+    do {
+        /* get next write job in order */
+        possess(write_first);
+        wait_for(write_first, TO_BE, seq);
+        job = write_head;
+        write_head = job->next;
+        twist(write_first, TO, write_head == NULL ? -1 : write_head->seq);
+
+        /* update lengths, save uncompressed length for COMB */
+        more = job->more;
+        len = job->in->len;
+        drop_space(job->in);
+        ulen += (unsigned long)len;
+        clen += (unsigned long)(job->out->len);
+
+        /* write the compressed data and drop the output buffer */
+        Trace(("-- writing #%ld", seq));
+        writen(outd, job->out->buf, job->out->len);
+        drop_space(job->out);
+        Trace(("-- wrote #%ld%s", seq, more ? "" : " (last)"));
+
+        /* wait for check calculation to complete, then combine, once
+           the compress thread is done with the input, release it */
+        possess(job->calc);
+        wait_for(job->calc, TO_BE, 1);
+        release(job->calc);
+        check = COMB(check, job->check, len);
+
+        /* free the job */
+        free_lock(job->calc);
+        free(job);
+
+        /* get the next buffer in sequence */
+        seq++;
+    } while (more);
+
+    /* write trailer */
+    put_trailer(ulen, clen, check, head);
+
+    /* verify no more jobs, prepare for next use */
+    possess(compress_have);
+    assert(compress_head == NULL && peek_lock(compress_have) == 0);
+    release(compress_have);
+    possess(write_first);
+    assert(write_head == NULL);
+    twist(write_first, TO, -1);
+}
+
+/* compress ind to outd, using multiple threads for the compression and check
+   value calculations and one other thread for writing the output -- compress
+   threads will be launched and left running (waiting actually) to support
+   subsequent calls of parallel_compress() */
+local void parallel_compress(void)
+{
+    long seq;                       /* sequence number */
+    struct space *prev;             /* previous input space */
+    struct space *next;             /* next input space */
+    struct job *job;                /* job for compress, then write */
+    int more;                       /* true if more input to read */
+
+    /* if first time or after an option change, setup the job lists */
+    setup_jobs();
+
+    /* start write thread */
+    writeth = launch(write_thread, NULL);
+
+    /* read from input and start compress threads (write thread will pick up
+       the output of the compress threads) */
+    seq = 0;
+    prev = NULL;
+    next = get_space(&in_pool);
+    next->len = readn(ind, next->buf, next->pool->size);
+    do {
+        /* create a new job, use next input chunk, previous as dictionary */
+        job = malloc(sizeof(struct job));
+        if (job == NULL)
+            bail("not enough memory", "");
+        job->seq = seq;
+        job->in = next;
+        job->out = dict ? prev : NULL;  /* dictionary for compression */
+        job->calc = new_lock(0);
+
+        /* check for end of file, reading next chunk if not sure */
+        if (next->len < next->pool->size)
+            more = 0;
+        else {
+            next = get_space(&in_pool);
+            next->len = readn(ind, next->buf, next->pool->size);
+            more = next->len != 0;
+            if (!more)
+                drop_space(next);       /* won't be using it */
+            if (dict && more) {
+                use_space(job->in);     /* hold as dictionary for next loop */
+                prev = job->in;
+            }
+        }
+        job->more = more;
+        Trace(("-- read #%ld%s", seq, more ? "" : " (last)"));
+        if (++seq < 1)
+            bail("input too long: ", in);
+
+        /* start another compress thread if needed */
+        if (cthreads < seq && cthreads < procs) {
+            (void)launch(compress_thread, NULL);
+            cthreads++;
+        }
+
+        /* put job at end of compress list, let all the compressors know */
+        possess(compress_have);
+        job->next = NULL;
+        *compress_tail = job;
+        compress_tail = &(job->next);
+        twist(compress_have, BY, +1);
+
+        /* do until end of input */
+    } while (more);
+
+    /* wait for the write thread to complete (we leave the compress threads out
+       there and waiting in case there is another stream to compress) */
+    join(writeth);
+    writeth = NULL;
+    Trace(("-- write thread joined"));
+}
+
+#endif
+
+/* do a simple compression in a single thread from ind to outd -- if reset is
+   true, instead free the memory that was allocated and retained for input,
+   output, and deflate */
+local void single_compress(int reset)
+{
+    size_t got;                     /* amount read */
+    size_t more;                    /* amount of next read (0 if eof) */
+    unsigned long head;             /* header length */
+    unsigned long ulen;             /* total uncompressed size (overflow ok) */
+    unsigned long clen;             /* total compressed size (overflow ok) */
+    unsigned long check;            /* check value of uncompressed data */
+    static unsigned out_size;       /* size of output buffer */
+    static unsigned char *in, *next, *out;  /* reused i/o buffers */
+    static z_stream *strm = NULL;   /* reused deflate structure */
+
+    /* if requested, just release the allocations and return */
+    if (reset) {
+        if (strm != NULL) {
+            deflateEnd(strm);
+            free(strm);
+            free(out);
+            free(next);
+            free(in);
+            strm = NULL;
+        }
+        return;
+    }
+
+    /* initialize the deflate structure if this is the first time */
+    if (strm == NULL) {
+        out_size = size > MAX ? MAX : (unsigned)size;
+        if ((in = malloc(size)) == NULL ||
+            (next = malloc(size)) == NULL ||
+            (out = malloc(out_size)) == NULL ||
+            (strm = malloc(sizeof(z_stream))) == NULL)
+            bail("not enough memory", "");
+        strm->zfree = Z_NULL;
+        strm->zalloc = Z_NULL;
+        strm->opaque = Z_NULL;
+        if (deflateInit2(strm, level, Z_DEFLATED, -15, 8,
+                         Z_DEFAULT_STRATEGY) != Z_OK)
+            bail("not enough memory", "");
+    }
+
+    /* write header */
+    head = put_header();
+
+    /* set compression level in case it changed */
+    (void)deflateReset(strm);
+    (void)deflateParams(strm, level, Z_DEFAULT_STRATEGY);
+
+    /* do raw deflate and calculate check value */
+    ulen = clen = 0;
+    check = CHECK(0L, Z_NULL, 0);
+    more = readn(ind, next, size);
+    do {
+        /* get data to compress, see if there is any more input */
+        got = more;
+        { unsigned char *temp; temp = in; in = next; next = temp; }
+        more = got < size ? 0 : readn(ind, next, size);
+        ulen += (unsigned long)got;
+        strm->next_in = in;
+
+        /* compress MAX-size chunks in case unsigned type is small */
+        while (got > MAX) {
+            strm->avail_in = MAX;
+            check = CHECK(check, strm->next_in, strm->avail_in);
+            do {
+                strm->avail_out = out_size;
+                strm->next_out = out;
+                (void)deflate(strm, Z_NO_FLUSH);
+                writen(outd, out, out_size - strm->avail_out);
+                clen += out_size - strm->avail_out;
+            } while (strm->avail_out == 0);
+            assert(strm->avail_in == 0);
+            got -= MAX;
+        }
+
+        /* compress the remainder, finishing if end of input -- when not -i,
+           use a Z_SYNC_FLUSH so that this and parallel compression produce the
+           same output */
+        strm->avail_in = (unsigned)got;
+        check = CHECK(check, strm->next_in, strm->avail_in);
+        do {
+            strm->avail_out = out_size;
+            strm->next_out = out;
+            (void)deflate(strm,
+                more ? (dict ? Z_SYNC_FLUSH : Z_FULL_FLUSH) : Z_FINISH);
+            writen(outd, out, out_size - strm->avail_out);
+            clen += out_size - strm->avail_out;
+        } while (strm->avail_out == 0);
+        assert(strm->avail_in == 0);
+
+        /* do until no more input */
+    } while (more);
+
+    /* write trailer */
+    put_trailer(ulen, clen, check, head);
+}
+
+/* --- decompression --- */
+
+/* globals for decompression and listing buffered reading */
+#define BUF 32768U                  /* input buffer size */
+local unsigned char in_buf[BUF];    /* input buffer */
+local unsigned char *in_next;       /* next unused byte in buffer */
+local size_t in_left;               /* number of unused bytes in buffer */
+local int in_eof;                   /* true if reached end of file on input */
+local int in_short;                 /* true if last read didn't fill buffer */
+local off_t in_tot;                 /* total bytes read from input */
+local off_t out_tot;                /* total bytes written to output */
+local unsigned long out_check;      /* check value of output */
+
+#ifndef NOTHREAD
+/* parallel reading */
+
+local unsigned char in_buf2[BUF];   /* second buffer for parallel reads */
+local size_t in_len;                /* data waiting in next buffer */
+local int in_which;                 /* -1: start, 0: in_buf2, 1: in_buf */
+local lock *load_state;             /* value = 0 to wait, 1 to read a buffer */
+local thread *load_thread;          /* load_read() thread for joining */
+
+/* parallel read thread */
+local void load_read(void *dummy)
+{
+    size_t len;
+
+    (void)dummy;
+
+    Trace(("-- launched decompress read thread"));
+    do {
+        possess(load_state);
+        wait_for(load_state, TO_BE, 1);
+        in_len = len = readn(ind, in_which ? in_buf : in_buf2, BUF);
+        Trace(("-- decompress read thread read %lu bytes", len));
+        twist(load_state, TO, 0);
+    } while (len == BUF);
+    Trace(("-- exited decompress read thread"));
+}
+
+#endif
+
+/* load() is called when in_left has gone to zero in order to provide more
+   input data: load the input buffer with BUF or less bytes (less if at end of
+   file) from the file ind, set in_next to point to the in_left bytes read,
+   update in_tot, and return in_left -- in_eof is set to true when in_left has
+   gone to zero and there is no more data left to read from ind */
+local size_t load(void)
+{
+    /* if already detected end of file, do nothing */
+    if (in_short) {
+        in_eof = 1;
+        return 0;
+    }
+
+#ifndef NOTHREAD
+    /* if first time in or procs == 1, read a buffer to have something to
+       return, otherwise wait for the previous read job to complete */
+    if (procs > 1) {
+        /* if first time, fire up the read thread, ask for a read */
+        if (in_which == -1) {
+            in_which = 1;
+            load_state = new_lock(1);
+            load_thread = launch(load_read, NULL);
+        }
+
+        /* wait for the previously requested read to complete */
+        possess(load_state);
+        wait_for(load_state, TO_BE, 0);
+        release(load_state);
+
+        /* set up input buffer with the data just read */
+        in_next = in_which ? in_buf : in_buf2;
+        in_left = in_len;
+
+        /* if not at end of file, alert read thread to load next buffer,
+           alternate between in_buf and in_buf2 */
+        if (in_len == BUF) {
+            in_which = 1 - in_which;
+            possess(load_state);
+            twist(load_state, TO, 1);
+        }
+
+        /* at end of file -- join read thread (already exited), clean up */
+        else {
+            join(load_thread);
+            free_lock(load_state);
+            in_which = -1;
+        }
+    }
+    else
+#endif
+    {
+        /* don't use threads -- simply read a buffer into in_buf */
+        in_left = readn(ind, in_next = in_buf, BUF);
+    }
+
+    /* note end of file */
+    if (in_left < BUF) {
+        in_short = 1;
+
+        /* if we got bupkis, now is the time to mark eof */
+        if (in_left == 0)
+            in_eof = 1;
+    }
+
+    /* update the total and return the available bytes */
+    in_tot += in_left;
+    return in_left;
+}
+
+/* initialize for reading new input */
+local void in_init(void)
+{
+    in_left = 0;
+    in_eof = 0;
+    in_short = 0;
+    in_tot = 0;
+#ifndef NOTHREAD
+    in_which = -1;
+#endif
+}
+
+/* buffered reading macros for decompression and listing */
+#define GET() (in_eof || (in_left == 0 && load() == 0) ? EOF : \
+               (in_left--, *in_next++))
+#define GET2() (tmp2 = GET(), tmp2 + (GET() << 8))
+#define GET4() (tmp4 = GET2(), tmp4 + ((unsigned long)(GET2()) << 16))
+#define SKIP(dist) \
+    do { \
+        size_t togo = (dist); \
+        while (togo > in_left) { \
+            togo -= in_left; \
+            if (load() == 0) \
+                return -1; \
+        } \
+        in_left -= togo; \
+        in_next += togo; \
+    } while (0)
+
+/* convert MS-DOS date and time to a Unix time, assuming current timezone
+   (you got a better idea?) */
+local time_t dos2time(unsigned long dos)
+{
+    struct tm tm;
+
+    if (dos == 0)
+        return time(NULL);
+    tm.tm_year = ((int)(dos >> 25) & 0x7f) + 80;
+    tm.tm_mon  = ((int)(dos >> 21) & 0xf) - 1;
+    tm.tm_mday = (int)(dos >> 16) & 0x1f;
+    tm.tm_hour = (int)(dos >> 11) & 0x1f;
+    tm.tm_min  = (int)(dos >> 5) & 0x3f;
+    tm.tm_sec  = (int)(dos << 1) & 0x3e;
+    tm.tm_isdst = -1;           /* figure out if DST or not */
+    return mktime(&tm);
+}
+
+/* convert an unsigned 32-bit integer to signed, even if long > 32 bits */
+local long tolong(unsigned long val)
+{
+    return (long)(val & 0x7fffffffUL) - (long)(val & 0x80000000UL);
+}
+
+#define LOW32 0xffffffffUL
+
+/* process zip extra field to extract zip64 lengths and Unix mod time */
+local int read_extra(unsigned len, int save)
+{
+    unsigned id, size, tmp2;
+    unsigned long tmp4;
+
+    /* process extra blocks */
+    while (len >= 4) {
+        id = GET2();
+        size = GET2();
+        if (in_eof)
+            return -1;
+        len -= 4;
+        if (size > len)
+            break;
+        len -= size;
+        if (id == 0x0001) {
+            /* Zip64 Extended Information Extra Field */
+            if (zip_ulen == LOW32 && size >= 8) {
+                zip_ulen = GET4();
+                SKIP(4);
+                size -= 8;
+            }
+            if (zip_clen == LOW32 && size >= 8) {
+                zip_clen = GET4();
+                SKIP(4);
+                size -= 8;
+            }
+        }
+        if (save) {
+            if ((id == 0x000d || id == 0x5855) && size >= 8) {
+                /* PKWare Unix or Info-ZIP Type 1 Unix block */
+                SKIP(4);
+                stamp = tolong(GET4());
+                size -= 8;
+            }
+            if (id == 0x5455 && size >= 5) {
+                /* Extended Timestamp block */
+                size--;
+                if (GET() & 1) {
+                    stamp = tolong(GET4());
+                    size -= 4;
+                }
+            }
+        }
+        SKIP(size);
+    }
+    SKIP(len);
+    return 0;
+}
+
+/* read a gzip, zip, zlib, or lzw header from ind and extract useful
+   information, return the method -- or on error return negative: -1 is
+   immediate EOF, -2 is not a recognized compressed format, -3 is premature EOF
+   within the header, -4 is unexpected header flag values; a method of 256 is
+   lzw -- set form to indicate gzip, zlib, or zip */
+local int get_header(int save)
+{
+    unsigned magic;             /* magic header */
+    int method;                 /* compression method */
+    int flags;                  /* header flags */
+    unsigned fname, extra;      /* name and extra field lengths */
+    unsigned tmp2;              /* for macro */
+    unsigned long tmp4;         /* for macro */
+
+    /* clear return information */
+    if (save) {
+        stamp = 0;
+        RELEASE(hname);
+    }
+
+    /* see if it's a gzip, zlib, or lzw file */
+    form = 0;
+    magic = GET() << 8;
+    if (in_eof)
+        return -1;
+    magic += GET();
+    if (in_eof)
+        return -2;
+    if (magic % 31 == 0) {          /* it's zlib */
+        form = 1;
+        return (int)((magic >> 8) & 0xf);
+    }
+    if (magic == 0x1f9d)            /* it's lzw */
+        return 256;
+    if (magic == 0x504b) {          /* it's zip */
+        if (GET() != 3 || GET() != 4)
+            return -3;
+        SKIP(2);
+        flags = GET2();
+        if (in_eof)
+            return -3;
+        if (flags & 0xfff0)
+            return -4;
+        method = GET2();
+        if (flags & 1)              /* encrypted */
+            method = 255;           /* mark as unknown method */
+        if (in_eof)
+            return -3;
+        if (save)
+            stamp = dos2time(GET4());
+        else
+            SKIP(4);
+        zip_crc = GET4();
+        zip_clen = GET4();
+        zip_ulen = GET4();
+        fname = GET2();
+        extra = GET2();
+        if (save) {
+            char *next = hname = malloc(fname + 1);
+            if (hname == NULL)
+                bail("not enough memory", "");
+            while (fname > in_left) {
+                memcpy(next, in_next, in_left);
+                fname -= in_left;
+                next += in_left;
+                if (load() == 0)
+                    return -3;
+            }
+            memcpy(next, in_next, fname);
+            in_left -= fname;
+            in_next += fname;
+            next += fname;
+            *next = 0;
+        }
+        else
+            SKIP(fname);
+        read_extra(extra, save);
+        form = 2 + ((flags & 8) >> 3);
+        return in_eof ? -3 : method;
+    }
+    if (magic != 0x1f8b)            /* not gzip */
+        return -2;
+
+    /* it's gzip -- get method and flags */
+    method = GET();
+    flags = GET();
+    if (in_eof)
+        return -1;
+    if (flags & 0xe0)
+        return -4;
+
+    /* get time stamp */
+    if (save)
+        stamp = tolong(GET4());
+    else
+        SKIP(4);
+
+    /* skip extra field and OS */
+    SKIP(2);
+
+    /* skip extra field, if present */
+    if (flags & 4) {
+        extra = GET2();
+        if (in_eof)
+            return -3;
+        SKIP(extra);
+    }
+
+    /* read file name, if present, into allocated memory */
+    if ((flags & 8) && save) {
+        unsigned char *end;
+        size_t copy, have, size = 128;
+        hname = malloc(size);
+        if (hname == NULL)
+            bail("not enough memory", "");
+        have = 0;
+        do {
+            if (in_left == 0 && load() == 0)
+                return -3;
+            end = memchr(in_next, 0, in_left);
+            copy = end == NULL ? in_left : (size_t)(end - in_next) + 1;
+            if (have + copy > size) {
+                while (have + copy > (size <<= 1))
+                    ;
+                hname = realloc(hname, size);
+                if (hname == NULL)
+                    bail("not enough memory", "");
+            }
+            memcpy(hname + have, in_next, copy);
+            have += copy;
+            in_left -= copy;
+            in_next += copy;
+        } while (end == NULL);
+    }
+    else if (flags & 8)
+        while (GET() != 0)
+            if (in_eof)
+                return -3;
+
+    /* skip comment */
+    if (flags & 16)
+        while (GET() != 0)
+            if (in_eof)
+                return -3;
+
+    /* skip header crc */
+    if (flags & 2)
+        SKIP(2);
+
+    /* return compression method */
+    return method;
+}
+
+/* --- list contents of compressed input (gzip, zlib, or lzw) */
+
+/* find standard compressed file suffix, return length of suffix */
+local size_t compressed_suffix(char *nm)
+{
+    size_t len;
+
+    len = strlen(nm);
+    if (len > 4) {
+        nm += len - 4;
+        len = 4;
+        if (strcmp(nm, ".zip") == 0 || strcmp(nm, ".ZIP") == 0 ||
+            strcmp(nm, ".tgz") == 0)
+            return 4;
+    }
+    if (len > 3) {
+        nm += len - 3;
+        len = 3;
+        if (strcmp(nm, ".gz") == 0 || strcmp(nm, "-gz") == 0 ||
+            strcmp(nm, ".zz") == 0 || strcmp(nm, "-zz") == 0)
+            return 3;
+    }
+    if (len > 2) {
+        nm += len - 2;
+        if (strcmp(nm, ".z") == 0 || strcmp(nm, "-z") == 0 ||
+            strcmp(nm, "_z") == 0 || strcmp(nm, ".Z") == 0)
+            return 2;
+    }
+    return 0;
+}
+
+/* listing file name lengths for -l and -lv */
+#define NAMEMAX1 48     /* name display limit at verbosity 1 */
+#define NAMEMAX2 16     /* name display limit at verbosity 2 */
+
+/* print gzip or lzw file information */
+local void show_info(int method, unsigned long check, off_t len, int cont)
+{
+    size_t max;             /* maximum name length for current verbosity */
+    size_t n;               /* name length without suffix */
+    time_t now;             /* for getting current year */
+    char mod[26];           /* modification time in text */
+    char name[NAMEMAX1+1];  /* header or file name, possibly truncated */
+
+    /* create abbreviated name from header file name or actual file name */
+    max = verbosity > 1 ? NAMEMAX2 : NAMEMAX1;
+    memset(name, 0, max + 1);
+    if (cont)
+        strncpy(name, "<...>", max + 1);
+    else if (hname == NULL) {
+        n = strlen(in) - compressed_suffix(in);
+        strncpy(name, in, n > max + 1 ? max + 1 : n);
+    }
+    else
+        strncpy(name, hname, max + 1);
+    if (name[max])
+        strcpy(name + max - 3, "...");
+
+    /* convert time stamp to text */
+    if (stamp) {
+        strcpy(mod, ctime(&stamp));
+        now = time(NULL);
+        if (strcmp(mod + 20, ctime(&now) + 20) != 0)
+            strcpy(mod + 11, mod + 19);
+    }
+    else
+        strcpy(mod + 4, "------ -----");
+    mod[16] = 0;
+
+    /* if first time, print header */
+    if (first) {
+        if (verbosity > 1)
+            fputs("method    check    timestamp    ", stdout);
+        if (verbosity > 0)
+            puts("compressed   original reduced  name");
+        first = 0;
+    }
+
+    /* print information */
+    if (verbosity > 1) {
+        if (form == 3 && !decode)
+            printf("zip%3d  --------  %s  ", method, mod + 4);
+        else if (form > 1)
+            printf("zip%3d  %08lx  %s  ", method, check, mod + 4);
+        else if (form)
+            printf("zlib%2d  %08lx  %s  ", method, check, mod + 4);
+        else if (method == 256)
+            printf("lzw     --------  %s  ", mod + 4);
+        else
+            printf("gzip%2d  %08lx  %s  ", method, check, mod + 4);
+    }
+    if (verbosity > 0) {
+        if ((form == 3 && !decode) ||
+            (method == 8 && in_tot > (len + (len >> 10) + 12)) ||
+            (method == 256 && in_tot > len + (len >> 1) + 3))
+            printf(sizeof(off_t) == 4 ? "%10lu %10lu?  unk    %s\n" :
+                                        "%10llu %10llu?  unk    %s\n",
+                   in_tot, len, name);
+        else
+            printf(sizeof(off_t) == 4 ? "%10lu %10lu %6.1f%%  %s\n" :
+                                        "%10llu %10llu %6.1f%%  %s\n",
+                   in_tot, len,
+                   len == 0 ? 0 : 100 * (len - in_tot)/(double)len,
+                   name);
+    }
+}
+
+/* list content information about the gzip file at ind (only works if the gzip
+   file contains a single gzip stream with no junk at the end, and only works
+   well if the uncompressed length is less than 4 GB) */
+local void list_info(void)
+{
+    int method;             /* get_header() return value */
+    size_t n;               /* available trailer bytes */
+    off_t at;               /* used to calculate compressed length */
+    unsigned char tail[8];  /* trailer containing check and length */
+    unsigned long check, len;   /* check value and length from trailer */
+
+    /* initialize input buffer */
+    in_init();
+
+    /* read header information and position input after header */
+    method = get_header(1);
+    if (method < 0) {
+        RELEASE(hname);
+        if (method != -1 && verbosity > 1)
+            fprintf(stderr, "%s not a compressed file -- skipping\n", in);
+        return;
+    }
+
+    /* list zip file */
+    if (form > 1) {
+        in_tot = zip_clen;
+        show_info(method, zip_crc, zip_ulen, 0);
+        return;
+    }
+
+    /* list zlib file */
+    if (form) {
+        at = lseek(ind, 0, SEEK_END);
+        if (at == -1) {
+            check = 0;
+            do {
+                len = in_left < 4 ? in_left : 4;
+                in_next += in_left - len;
+                while (len--)
+                    check = (check << 8) + *in_next++;
+            } while (load() != 0);
+            check &= LOW32;
+        }
+        else {
+            in_tot = at;
+            lseek(ind, -4, SEEK_END);
+            readn(ind, tail, 4);
+            check = (*tail << 24) + (tail[1] << 16) + (tail[2] << 8) + tail[3];
+        }
+        in_tot -= 6;
+        show_info(method, check, 0, 0);
+        return;
+    }
+
+    /* list lzw file */
+    if (method == 256) {
+        at = lseek(ind, 0, SEEK_END);
+        if (at == -1)
+            while (load() != 0)
+                ;
+        else
+            in_tot = at;
+        in_tot -= 3;
+        show_info(method, 0, 0, 0);
+        return;
+    }
+
+    /* skip to end to get trailer (8 bytes), compute compressed length */
+    if (in_short) {                     /* whole thing already read */
+        if (in_left < 8) {
+            if (verbosity > 0)
+                fprintf(stderr, "%s not a valid gzip file -- skipping\n",
+                        in);
+            return;
+        }
+        in_tot = in_left - 8;           /* compressed size */
+        memcpy(tail, in_next + (in_left - 8), 8);
+    }
+    else if ((at = lseek(ind, -8, SEEK_END)) != -1) {
+        in_tot = at - in_tot + in_left; /* compressed size */
+        readn(ind, tail, 8);            /* get trailer */
+    }
+    else {                              /* can't seek */
+        at = in_tot - in_left;          /* save header size */
+        do {
+            n = in_left < 8 ? in_left : 8;
+            memcpy(tail, in_next + (in_left - n), n);
+            load();
+        } while (in_left == BUF);       /* read until end */
+        if (in_left < 8) {
+            if (n + in_left < 8) {
+                if (verbosity > 0)
+                    fprintf(stderr, "%s not a valid gzip file -- skipping\n",
+                            in);
+                return;
+            }
+            if (in_left) {
+                if (n + in_left > 8)
+                    memcpy(tail, tail + n - (8 - in_left), 8 - in_left);
+                memcpy(tail + 8 - in_left, in_next, in_left);
+            }
+        }
+        else
+            memcpy(tail, in_next + (in_left - 8), 8);
+        in_tot -= at + 8;
+    }
+    if (in_tot < 2) {
+        if (verbosity > 0)
+            fprintf(stderr, "%s not a valid gzip file -- skipping\n", in);
+        return;
+    }
+
+    /* convert trailer to check and uncompressed length (modulo 2^32) */
+    check = tail[0] + (tail[1] << 8) + (tail[2] << 16) + (tail[3] << 24);
+    len = tail[4] + (tail[5] << 8) + (tail[6] << 16) + (tail[7] << 24);
+
+    /* list information about contents */
+    show_info(method, check, len, 0);
+    RELEASE(hname);
+}
+
+/* --- decompress deflate input --- */
+
+/* call-back input function for inflateBack() */
+local unsigned inb(void *desc, unsigned char **buf)
+{
+    (void)desc;
+    load();
+    *buf = in_next;
+    return in_left;
+}
+
+/* output buffers and window for infchk() and unlzw() */
+#define OUTSIZE 32768U      /* must be at least 32K for inflateBack() window */
+local unsigned char out_buf[OUTSIZE];
+
+#ifndef NOTHREAD
+/* output data for parallel write and check */
+local unsigned char out_copy[OUTSIZE];
+local size_t out_len;
+
+/* outb threads states */
+local lock *outb_write_more = NULL;
+local lock *outb_check_more;
+
+/* output write thread */
+local void outb_write(void *dummy)
+{
+    size_t len;
+
+    (void)dummy;
+
+    Trace(("-- launched decompress write thread"));
+    do {
+        possess(outb_write_more);
+        wait_for(outb_write_more, TO_BE, 1);
+        len = out_len;
+        if (len && decode == 1)
+            writen(outd, out_copy, len);
+        Trace(("-- decompress wrote %lu bytes", len));
+        twist(outb_write_more, TO, 0);
+    } while (len);
+    Trace(("-- exited decompress write thread"));
+}
+
+/* output check thread */
+local void outb_check(void *dummy)
+{
+    size_t len;
+
+    (void)dummy;
+
+    Trace(("-- launched decompress check thread"));
+    do {
+        possess(outb_check_more);
+        wait_for(outb_check_more, TO_BE, 1);
+        len = out_len;
+        out_check = CHECK(out_check, out_copy, len);
+        Trace(("-- decompress checked %lu bytes", len));
+        twist(outb_check_more, TO, 0);
+    } while (len);
+    Trace(("-- exited decompress check thread"));
+}
+#endif
+
+/* call-back output function for inflateBack() -- wait for the last write and
+   check calculation to complete, copy the write buffer, and then alert the
+   write and check threads and return for more decompression while that's
+   going on (or just write and check if no threads or if proc == 1) */
+local int outb(void *desc, unsigned char *buf, unsigned len)
+{
+#ifndef NOTHREAD
+    static thread *wr, *ch;
+
+    (void)desc;
+
+    if (procs > 1) {
+        /* if first time, initialize state and launch threads */
+        if (outb_write_more == NULL) {
+            outb_write_more = new_lock(0);
+            outb_check_more = new_lock(0);
+            wr = launch(outb_write, NULL);
+            ch = launch(outb_check, NULL);
+        }
+
+        /* wait for previous write and check threads to complete */
+        possess(outb_check_more);
+        wait_for(outb_check_more, TO_BE, 0);
+        possess(outb_write_more);
+        wait_for(outb_write_more, TO_BE, 0);
+
+        /* copy the output and alert the worker bees */
+        out_len = len;
+        out_tot += len;
+        memcpy(out_copy, buf, len);
+        twist(outb_write_more, TO, 1);
+        twist(outb_check_more, TO, 1);
+
+        /* if requested with len == 0, clean up -- terminate and join write and
+           check threads, free lock */
+        if (len == 0) {
+            join(ch);
+            join(wr);
+            free_lock(outb_check_more);
+            free_lock(outb_write_more);
+            outb_write_more = NULL;
+        }
+
+        /* return for more decompression while last buffer is being written
+           and having its check value calculated -- we wait for those to finish
+           the next time this function is called */
+        return 0;
+    }
+#endif
+
+    /* if just one process or no threads, then do it without threads */
+    if (len) {
+        if (decode == 1)
+            writen(outd, buf, len);
+        out_check = CHECK(out_check, buf, len);
+        out_tot += len;
+    }
+    return 0;
+}
+
+/* inflate for decompression or testing -- decompress from ind to outd unless
+   decode != 1, in which case just test ind, and then also list if list != 0;
+   look for and decode multiple, concatenated gzip and/or zlib streams;
+   read and check the gzip, zlib, or zip trailer */
+local void infchk(void)
+{
+    int ret, cont;
+    unsigned long check, len;
+    z_stream strm;
+    unsigned tmp2;
+    unsigned long tmp4;
+    off_t clen;
+
+    cont = 0;
+    do {
+        /* header already read -- set up for decompression */
+        in_tot = in_left;               /* track compressed data length */
+        out_tot = 0;
+        out_check = CHECK(0L, Z_NULL, 0);
+        strm.zalloc = Z_NULL;
+        strm.zfree = Z_NULL;
+        strm.opaque = Z_NULL;
+        ret = inflateBackInit(&strm, 15, out_buf);
+        if (ret != Z_OK)
+            bail("not enough memory", "");
+
+        /* decompress, compute lengths and check value */
+        strm.avail_in = in_left;
+        strm.next_in = in_next;
+        ret = inflateBack(&strm, inb, NULL, outb, NULL);
+        if (ret != Z_STREAM_END)
+            bail("corrupted input -- invalid deflate data: ", in);
+        in_left = strm.avail_in;
+        in_next = strm.next_in;
+        inflateBackEnd(&strm);
+        outb(NULL, NULL, 0);        /* finish off final write and check */
+
+        /* compute compressed data length */
+        clen = in_tot - in_left;
+
+        /* read and check trailer */
+        if (form > 1) {             /* zip local trailer (if any) */
+            if (form == 3) {        /* data descriptor follows */
+                /* read original version of data descriptor*/
+                zip_crc = GET4();
+                zip_clen = GET4();
+                zip_ulen = GET4();
+                if (in_eof)
+                    bail("corrupted zip entry -- missing trailer: ", in);
+
+                /* if crc doesn't match, try info-zip variant with sig */
+                if (zip_crc != out_check) {
+                    if (zip_crc != 0x08074b50UL || zip_clen != out_check)
+                        bail("corrupted zip entry -- crc32 mismatch: ", in);
+                    zip_crc = zip_clen;
+                    zip_clen = zip_ulen;
+                    zip_ulen = GET4();
+                }
+
+                /* if second length doesn't match, try 64-bit lengths */
+                if (zip_ulen != (out_tot & LOW32)) {
+                    zip_ulen = GET4();
+                    (void)GET4();
+                }
+                if (in_eof)
+                    bail("corrupted zip entry -- missing trailer: ", in);
+            }
+            if (zip_clen != (clen & LOW32) || zip_ulen != (out_tot & LOW32))
+                bail("corrupted zip entry -- length mismatch: ", in);
+            check = zip_crc;
+        }
+        else if (form == 1) {       /* zlib (big-endian) trailer */
+            check = (unsigned long)(GET()) << 24;
+            check += (unsigned long)(GET()) << 16;
+            check += GET() << 8;
+            check += GET();
+            if (in_eof)
+                bail("corrupted zlib stream -- missing trailer: ", in);
+            if (check != out_check)
+                bail("corrupted zlib stream -- adler32 mismatch: ", in);
+        }
+        else {                      /* gzip trailer */
+            check = GET4();
+            len = GET4();
+            if (in_eof)
+                bail("corrupted gzip stream -- missing trailer: ", in);
+            if (check != out_check)
+                bail("corrupted gzip stream -- crc32 mismatch: ", in);
+            if (len != (out_tot & LOW32))
+                bail("corrupted gzip stream -- length mismatch: ", in);
+        }
+
+        /* show file information if requested */
+        if (list) {
+            in_tot = clen;
+            show_info(8, check, out_tot, cont);
+            cont = 1;
+        }
+
+        /* if a gzip or zlib entry follows a gzip or zlib entry, decompress it
+           (don't replace saved header information from first entry) */
+    } while (form < 2 && (ret = get_header(0)) == 8 && form < 2);
+    if (ret != -1 && form < 2)
+        fprintf(stderr, "%s OK, has trailing junk which was ignored\n", in);
+}
+
+/* --- decompress Unix compress (LZW) input --- */
+
+/* memory for unlzw() --
+   the first 256 entries of prefix[] and suffix[] are never used, could
+   have offset the index, but it's faster to waste the memory */
+unsigned short prefix[65536];           /* index to LZW prefix string */
+unsigned char suffix[65536];            /* one-character LZW suffix */
+unsigned char match[65280 + 2];         /* buffer for reversed match */
+
+/* throw out what's left in the current bits byte buffer (this is a vestigial
+   aspect of the compressed data format derived from an implementation that
+   made use of a special VAX machine instruction!) */
+#define FLUSHCODE() \
+    do { \
+        left = 0; \
+        rem = 0; \
+        if (chunk > in_left) { \
+            chunk -= in_left; \
+            if (load() == 0) \
+                break; \
+            if (chunk > in_left) { \
+                chunk = in_left = 0; \
+                break; \
+            } \
+        } \
+        in_left -= chunk; \
+        in_next += chunk; \
+        chunk = 0; \
+    } while (0)
+
+/* Decompress a compress (LZW) file from ind to outd.  The compress magic
+   header (two bytes) has already been read and verified. */
+local void unlzw(void)
+{
+    int got;                    /* byte just read by GET() */
+    unsigned chunk;             /* bytes left in current chunk */
+    int left;                   /* bits left in rem */
+    unsigned rem;               /* unused bits from input */
+    int bits;                   /* current bits per code */
+    unsigned code;              /* code, table traversal index */
+    unsigned mask;              /* mask for current bits codes */
+    int max;                    /* maximum bits per code for this stream */
+    int flags;                  /* compress flags, then block compress flag */
+    unsigned end;               /* last valid entry in prefix/suffix tables */
+    unsigned temp;              /* current code */
+    unsigned prev;              /* previous code */
+    unsigned final;             /* last character written for previous code */
+    unsigned stack;             /* next position for reversed string */
+    unsigned outcnt;            /* bytes in output buffer */
+    unsigned char *p;
+
+    /* process remainder of compress header -- a flags byte */
+    out_tot = 0;
+    flags = GET();
+    if (in_eof)
+        bail("missing lzw data: ", in);
+    if (flags & 0x60)
+        bail("unknown lzw flags set: ", in);
+    max = flags & 0x1f;
+    if (max < 9 || max > 16)
+        bail("lzw bits out of range: ", in);
+    if (max == 9)                           /* 9 doesn't really mean 9 */
+        max = 10;
+    flags &= 0x80;                          /* true if block compress */
+
+    /* clear table */
+    bits = 9;
+    mask = 0x1ff;
+    end = flags ? 256 : 255;
+
+    /* set up: get first 9-bit code, which is the first decompressed byte, but
+       don't create a table entry until the next code */
+    got = GET();
+    if (in_eof)                             /* no compressed data is ok */
+        return;
+    final = prev = (unsigned)got;           /* low 8 bits of code */
+    got = GET();
+    if (in_eof || (got & 1) != 0)           /* missing a bit or code >= 256 */
+        bail("invalid lzw code: ", in);
+    rem = (unsigned)got >> 1;               /* remaining 7 bits */
+    left = 7;
+    chunk = bits - 2;                       /* 7 bytes left in this chunk */
+    out_buf[0] = (unsigned char)final;      /* write first decompressed byte */
+    outcnt = 1;
+
+    /* decode codes */
+    stack = 0;
+    for (;;) {
+        /* if the table will be full after this, increment the code size */
+        if (end >= mask && bits < max) {
+            FLUSHCODE();
+            bits++;
+            mask <<= 1;
+            mask++;
+        }
+
+        /* get a code of length bits */
+        if (chunk == 0)                     /* decrement chunk modulo bits */
+            chunk = bits;
+        code = rem;                         /* low bits of code */
+        got = GET();
+        if (in_eof) {                       /* EOF is end of compressed data */
+            /* write remaining buffered output */
+            out_tot += outcnt;
+            if (outcnt && decode == 1)
+                writen(outd, out_buf, outcnt);
+            return;
+        }
+        code += (unsigned)got << left;      /* middle (or high) bits of code */
+        left += 8;
+        chunk--;
+        if (bits > left) {                  /* need more bits */
+            got = GET();
+            if (in_eof)                     /* can't end in middle of code */
+                bail("invalid lzw code: ", in);
+            code += (unsigned)got << left;  /* high bits of code */
+            left += 8;
+            chunk--;
+        }
+        code &= mask;                       /* mask to current code length */
+        left -= bits;                       /* number of unused bits */
+        rem = (unsigned)got >> (8 - left);  /* unused bits from last byte */
+
+        /* process clear code (256) */
+        if (code == 256 && flags) {
+            FLUSHCODE();
+            bits = 9;                       /* initialize bits and mask */
+            mask = 0x1ff;
+            end = 255;                      /* empty table */
+            continue;                       /* get next code */
+        }
+
+        /* special code to reuse last match */
+        temp = code;                        /* save the current code */
+        if (code > end) {
+            /* Be picky on the allowed code here, and make sure that the code
+               we drop through (prev) will be a valid index so that random
+               input does not cause an exception.  The code != end + 1 check is
+               empirically derived, and not checked in the original uncompress
+               code.  If this ever causes a problem, that check could be safely
+               removed.  Leaving this check in greatly improves pigz's ability
+               to detect random or corrupted input after a compress header.
+               In any case, the prev > end check must be retained. */
+            if (code != end + 1 || prev > end)
+                bail("invalid lzw code: ", in);
+            match[stack++] = (unsigned char)final;
+            code = prev;
+        }
+
+        /* walk through linked list to generate output in reverse order */
+        p = match + stack;
+        while (code >= 256) {
+            *p++ = suffix[code];
+            code = prefix[code];
+        }
+        stack = p - match;
+        match[stack++] = (unsigned char)code;
+        final = code;
+
+        /* link new table entry */
+        if (end < mask) {
+            end++;
+            prefix[end] = (unsigned short)prev;
+            suffix[end] = (unsigned char)final;
+        }
+
+        /* set previous code for next iteration */
+        prev = temp;
+
+        /* write output in forward order */
+        while (stack > OUTSIZE - outcnt) {
+            while (outcnt < OUTSIZE)
+                out_buf[outcnt++] = match[--stack];
+            out_tot += outcnt;
+            if (decode == 1)
+                writen(outd, out_buf, outcnt);
+            outcnt = 0;
+        }
+        p = match + stack;
+        do {
+            out_buf[outcnt++] = *--p;
+        } while (p > match);
+        stack = 0;
+
+        /* loop for next code with final and prev as the last match, rem and
+           left provide the first 0..7 bits of the next code, end is the last
+           valid table entry */
+    }
+}
+
+/* --- file processing --- */
+
+/* extract file name from path */
+local char *justname(char *path)
+{
+    char *p;
+
+    p = path + strlen(path);
+    while (--p >= path)
+        if (*p == '/')
+            break;
+    return p + 1;
+}
+
+/* Copy file attributes, from -> to, as best we can.  This is best effort, so
+   no errors are reported.  The mode bits, including suid, sgid, and the sticky
+   bit are copied (if allowed), the owner's user id and group id are copied
+   (again if allowed), and the access and modify times are copied. */
+local void copymeta(char *from, char *to)
+{
+    struct stat st;
+    struct timeval times[2];
+
+    /* get all of from's Unix meta data, return if not a regular file */
+    if (stat(from, &st) != 0 || (st.st_mode & S_IFMT) != S_IFREG)
+        return;
+
+    /* set to's mode bits, ignore errors */
+    chmod(to, st.st_mode & 07777);
+
+    /* copy owner's user and group, ignore errors */
+    chown(to, st.st_uid, st.st_gid);
+
+    /* copy access and modify times, ignore errors */
+    times[0].tv_sec = st.st_atime;
+    times[0].tv_usec = 0;
+    times[1].tv_sec = st.st_mtime;
+    times[1].tv_usec = 0;
+    utimes(to, times);
+}
+
+/* set the access and modify times of fd to t */
+local void touch(char *path, time_t t)
+{
+    struct timeval times[2];
+
+    times[0].tv_sec = t;
+    times[0].tv_usec = 0;
+    times[1].tv_sec = t;
+    times[1].tv_usec = 0;
+    utimes(path, times);
+}
+
+/* process provided input file, or stdin if path is NULL -- process() can
+   call itself for recursive directory processing */
+local void process(char *path)
+{
+    int method = -1;                /* get_header() return value */
+    size_t len;                     /* length of base name (minus suffix) */
+    struct stat st;                 /* to get file type and mod time */
+
+    /* open input file with name in, descriptor ind -- set name and mtime */
+    if (path == NULL) {
+        strcpy(in, "<stdin>");
+        ind = 0;
+        name = NULL;
+        mtime = headis & 2 ?
+                (fstat(ind, &st) ? time(NULL) : st.st_mtime) : 0;
+        len = 0;
+    }
+    else {
+        /* set input file name (already set if recursed here) */
+        if (path != in) {
+            strncpy(in, path, sizeof(in));
+            if (in[sizeof(in) - 1])
+                bail("name too long: ", path);
+        }
+        len = strlen(in);
+
+        /* only process regular files, but allow symbolic links if -f,
+           recurse into directory if -r */
+        if (lstat(in, &st)) {
+#ifdef EOVERFLOW
+            if (errno == EOVERFLOW || errno == EFBIG)
+                bail(in,
+                    " too large -- pigz not compiled with large file support");
+#endif
+            if (verbosity > 0)
+                fprintf(stderr, "%s does not exist -- skipping\n", in);
+            return;
+        }
+        if ((st.st_mode & S_IFMT) != S_IFREG &&
+            (st.st_mode & S_IFMT) != S_IFLNK &&
+            (st.st_mode & S_IFMT) != S_IFDIR) {
+            if (verbosity > 0)
+                fprintf(stderr, "%s is a special file or device -- skipping\n",
+                        in);
+            return;
+        }
+        if ((st.st_mode & S_IFMT) == S_IFLNK && !force && !pipeout) {
+            if (verbosity > 0)
+                fprintf(stderr, "%s is a symbolic link -- skipping\n", in);
+            return;
+        }
+        if ((st.st_mode & S_IFMT) == S_IFDIR && !recurse) {
+            if (verbosity > 0)
+                fprintf(stderr, "%s is a directory -- skipping\n", in);
+            return;
+        }
+
+        /* recurse into directory (assumes Unix) */
+        if ((st.st_mode & S_IFMT) == S_IFDIR) {
+            char *roll, *item, *cut, *base, *bigger;
+            size_t len, hold;
+            DIR *here;
+            struct dirent *next;
+
+            /* accumulate list of entries (need to do this, since readdir()
+               behavior not defined if directory modified between calls) */
+            here = opendir(in);
+            if (here == NULL)
+                return;
+            hold = 512;
+            roll = malloc(hold);
+            if (roll == NULL)
+                bail("not enough memory", "");
+            *roll = 0;
+            item = roll;
+            while ((next = readdir(here)) != NULL) {
+                if (next->d_name[0] == 0 ||
+                    (next->d_name[0] == '.' && (next->d_name[1] == 0 ||
+                     (next->d_name[1] == '.' && next->d_name[2] == 0))))
+                    continue;
+                len = strlen(next->d_name) + 1;
+                if (item + len + 1 > roll + hold) {
+                    do {                    /* make roll bigger */
+                        hold <<= 1;
+                    } while (item + len + 1 > roll + hold);
+                    bigger = realloc(roll, hold);
+                    if (bigger == NULL) {
+                        free(roll);
+                        bail("not enough memory", "");
+                    }
+                    item = bigger + (item - roll);
+                    roll = bigger;
+                }
+                strcpy(item, next->d_name);
+                item += len;
+                *item = 0;
+            }
+            closedir(here);
+
+            /* run process() for each entry in the directory */
+            cut = base = in + strlen(in);
+            if (base > in && base[-1] != (unsigned char)'/') {
+                if ((size_t)(base - in) >= sizeof(in))
+                    bail("path too long", in);
+                *base++ = '/';
+            }
+            item = roll;
+            while (*item) {
+                strncpy(base, item, sizeof(in) - (base - in));
+                if (in[sizeof(in) - 1]) {
+                    strcpy(in + (sizeof(in) - 4), "...");
+                    bail("path too long: ", in);
+                }
+                process(in);
+                item += strlen(item) + 1;
+            }
+            *cut = 0;
+
+            /* release list of entries */
+            free(roll);
+            return;
+        }
+
+        /* don't compress .gz (or provided suffix) files, unless -f */
+        if (!(force || list || decode) && len >= strlen(sufx) &&
+                strcmp(in + len - strlen(sufx), sufx) == 0) {
+            if (verbosity > 0)
+                fprintf(stderr, "%s ends with %s -- skipping\n", in, sufx);
+            return;
+        }
+
+        /* only decompress or list files with compressed suffix */
+        if (list || decode) {
+            int suf = compressed_suffix(in);
+            if (suf == 0) {
+                if (verbosity > 0)
+                    fprintf(stderr,
+                            "%s does not have compressed suffix -- skipping\n",
+                            in);
+                return;
+            }
+            len -= suf;
+        }
+
+        /* open input file */
+        ind = open(in, O_RDONLY, 0);
+        if (ind < 0)
+            bail("read error on ", in);
+
+        /* prepare gzip header information for compression */
+        name = headis & 1 ? justname(in) : NULL;
+        mtime = headis & 2 ? st.st_mtime : 0;
+    }
+    SET_BINARY_MODE(ind);
+
+    /* if decoding or testing, try to read gzip header */
+    hname = NULL;
+    if (decode) {
+        in_init();
+        method = get_header(1);
+        if (method != 8 && method != 256) {
+            RELEASE(hname);
+            if (ind != 0)
+                close(ind);
+            if (method != -1 && verbosity > 0)
+                fprintf(stderr,
+                    method < 0 ? "%s is not compressed -- skipping\n" :
+                        "%s has unknown compression method -- skipping\n",
+                    in);
+            return;
+        }
+
+        /* if requested, test input file (possibly a special list) */
+        if (decode == 2) {
+            if (method == 8)
+                infchk();
+            else {
+                unlzw();
+                if (list) {
+                    in_tot -= 3;
+                    show_info(method, 0, out_tot, 0);
+                }
+            }
+            RELEASE(hname);
+            if (ind != 0)
+                close(ind);
+            return;
+        }
+    }
+
+    /* if requested, just list information about input file */
+    if (list) {
+        list_info();
+        RELEASE(hname);
+        if (ind != 0)
+            close(ind);
+        return;
+    }
+
+    /* create output file out, descriptor outd */
+    if (path == NULL || pipeout) {
+        /* write to stdout */
+        out = malloc(strlen("<stdout>") + 1);
+        if (out == NULL)
+            bail("not enough memory", "");
+        strcpy(out, "<stdout>");
+        outd = 1;
+        if (!decode && !force && isatty(outd))
+            bail("trying to write compressed data to a terminal",
+                 " (use -f to force)");
+    }
+    else {
+        char *to;
+
+        /* use header name for output when decompressing with -N */
+        to = in;
+        if (decode && (headis & 1) != 0 && hname != NULL) {
+            to = hname;
+            len = strlen(hname);
+        }
+
+        /* create output file and open to write */
+        out = malloc(len + (decode ? 0 : strlen(sufx)) + 1);
+        if (out == NULL)
+            bail("not enough memory", "");
+        memcpy(out, to, len);
+        strcpy(out + len, decode ? "" : sufx);
+        outd = open(out, O_CREAT | O_TRUNC | O_WRONLY |
+                         (force ? 0 : O_EXCL), 0666);
+
+        /* if exists and not -f, give user a chance to overwrite */
+        if (outd < 0 && errno == EEXIST && isatty(0) && verbosity) {
+            int ch, reply;
+
+            fprintf(stderr, "%s exists -- overwrite (y/n)? ", out);
+            fflush(stderr);
+            reply = -1;
+            do {
+                ch = getchar();
+                if (reply < 0 && ch != ' ' && ch != '\t')
+                    reply = ch == 'y' || ch == 'Y' ? 1 : 0;
+            } while (ch != EOF && ch != '\n' && ch != '\r');
+            if (reply == 1)
+                outd = open(out, O_CREAT | O_TRUNC | O_WRONLY,
+                            0666);
+        }
+
+        /* if exists and no overwrite, report and go on to next */
+        if (outd < 0 && errno == EEXIST) {
+            if (verbosity > 0)
+                fprintf(stderr, "%s exists -- skipping\n", out);
+            RELEASE(out);
+            RELEASE(hname);
+            if (ind != 0)
+                close(ind);
+            return;
+        }
+
+        /* if some other error, give up */
+        if (outd < 0)
+            bail("write error on ", out);
+    }
+    SET_BINARY_MODE(outd);
+    RELEASE(hname);
+
+    /* process ind to outd */
+    if (verbosity > 1)
+        fprintf(stderr, "%s to %s ", in, out);
+    if (decode) {
+        if (method == 8)
+            infchk();
+        else
+            unlzw();
+    }
+#ifndef NOTHREAD
+    else if (procs > 1)
+        parallel_compress();
+#endif
+    else
+        single_compress(0);
+    if (verbosity > 1) {
+        putc('\n', stderr);
+        fflush(stderr);
+    }
+
+    /* finish up, copy attributes, set times, delete original */
+    if (ind != 0)
+        close(ind);
+    if (outd != 1) {
+        if (close(outd))
+            bail("write error on ", out);
+        outd = -1;              /* now prevent deletion on interrupt */
+        if (ind != 0) {
+            copymeta(in, out);
+            if (!keep)
+                unlink(in);
+        }
+        if (decode && (headis & 2) != 0 && stamp)
+            touch(out, stamp);
+    }
+    RELEASE(out);
+}
+
+local char *helptext[] = {
+"Usage: pigz [options] [files ...]",
+"  will compress files in place, adding the suffix '.gz'.  If no files are",
+#ifdef NOTHREAD
+"  specified, stdin will be compressed to stdout.  pigz does what gzip does.",
+#else
+"  specified, stdin will be compressed to stdout.  pigz does what gzip does,",
+"  but spreads the work over multiple processors and cores when compressing.",
+#endif
+"",
+"Options:",
+"  -0 to -9, --fast, --best   Compression levels, --fast is -1, --best is -9",
+"  -b, --blocksize mmm  Set compression block size to mmmK (default 128K)",
+#ifndef NOTHREAD
+"  -p, --processes n    Allow up to n compression threads (default is the",
+"                       number of online processors, or 8 if unknown)",
+#endif
+"  -i, --independent    Compress blocks independently for damage recovery",
+"  -R, --rsyncable      Input-determined block locations for rsync",
+"  -d, --decompress     Decompress the compressed input",
+"  -t, --test           Test the integrity of the compressed input",
+"  -l, --list           List the contents of the compressed input",
+"  -f, --force          Force overwrite, compress .gz, links, and to terminal",
+"  -r, --recursive      Process the contents of all subdirectories",
+"  -S, --suffix .sss    Use suffix .sss instead of .gz (for compression)",
+"  -z, --zlib           Compress to zlib (.zz) instead of gzip format",
+"  -K, --zip            Compress to PKWare zip (.zip) single entry format",
+"  -k, --keep           Do not delete original file after processing",
+"  -c, --stdout         Write all processed output to stdout (won't delete)",
+"  -N, --name           Store/restore file name and mod time in/from header",
+"  -n, --no-name        Do not store or restore file name in/from header",
+"  -T, --no-time        Do not store or restore mod time in/from header",
+"  -q, --quiet          Print no messages, even on error",
+#ifdef DEBUG
+"  -v, --verbose        Provide more verbose output (-vv to debug)"
+#else
+"  -v, --verbose        Provide more verbose output"
+#endif
+};
+
+/* display the help text above */
+local void help(void)
+{
+    int n;
+
+    if (verbosity == 0)
+        return;
+    for (n = 0; n < (int)(sizeof(helptext) / sizeof(char *)); n++)
+        fprintf(stderr, "%s\n", helptext[n]);
+    fflush(stderr);
+    exit(0);
+}
+
+#ifndef NOTHREAD
+
+/* try to determine the number of processors */
+local int nprocs(int n)
+{
+#  ifdef _SC_NPROCESSORS_ONLN
+    n = (int)sysconf(_SC_NPROCESSORS_ONLN);
+#  else
+#    ifdef _SC_NPROC_ONLN
+    n = (int)sysconf(_SC_NPROC_ONLN);
+#    endif
+#  endif
+    return n;
+}
+
+#endif
+
+/* set option defaults */
+local void defaults(void)
+{
+    level = Z_DEFAULT_COMPRESSION;
+#ifdef NOTHREAD
+    procs = 1;
+#else
+    procs = nprocs(8);
+#endif
+    size = 131072UL;
+    rsync = 0;                      /* don't do rsync blocking */
+    dict = 1;                       /* initialize dictionary each thread */
+    verbosity = 1;                  /* normal message level */
+    headis = 3;                     /* store/restore name and timestamp */
+    pipeout = 0;                    /* don't force output to stdout */
+    sufx = ".gz";                   /* compressed file suffix */
+    decode = 0;                     /* compress */
+    list = 0;                       /* compress */
+    keep = 0;                       /* delete input file once compressed */
+    force = 0;                      /* don't overwrite, don't compress links */
+    recurse = 0;                    /* don't go into directories */
+    form = 0;                       /* use gzip format */
+}
+
+/* long options conversion to short options */
+local char *longopts[][2] = {
+    {"LZW", "Z"}, {"ascii", "a"}, {"best", "9"}, {"bits", "Z"},
+    {"blocksize", "b"}, {"decompress", "d"}, {"fast", "1"}, {"force", "f"},
+    {"help", "h"}, {"independent", "i"}, {"keep", "k"}, {"license", "L"},
+    {"list", "l"}, {"name", "N"}, {"no-name", "n"}, {"no-time", "T"},
+    {"processes", "p"}, {"quiet", "q"}, {"recursive", "r"}, {"rsyncable", "R"},
+    {"silent", "q"}, {"stdout", "c"}, {"suffix", "S"}, {"test", "t"},
+    {"to-stdout", "c"}, {"uncompress", "d"}, {"verbose", "v"},
+    {"version", "V"}, {"zip", "K"}, {"zlib", "z"}};
+#define NLOPTS (sizeof(longopts) / (sizeof(char *) << 1))
+
+/* either new buffer size, new compression level, or new number of processes --
+   get rid of old buffers and threads to force the creation of new ones with
+   the new settings */
+local void new_opts(void)
+{
+    single_compress(1);
+#ifndef NOTHREAD
+    finish_jobs();
+#endif
+}
+
+/* verify that arg is only digits, and if so, return the decimal value */
+local size_t num(char *arg)
+{
+    char *str = arg;
+    size_t val = 0;
+
+    if (*str == 0)
+        bail("internal error: empty parameter", "");
+    do {
+        if (*str < '0' || *str > '9')
+            bail("invalid numeric parameter: ", arg);
+        val = val * 10 + (*str - '0');
+        /* %% need to detect overflow here */
+    } while (*++str);
+    return val;
+}
+
+/* process an option, return true if a file name and not an option */
+local int option(char *arg)
+{
+    static int get = 0;     /* if not zero, look for option parameter */
+    char bad[3] = "-X";     /* for error messages (X is replaced) */
+
+    /* if no argument or dash option, check status of get */
+    if (get && (arg == NULL || *arg == '-')) {
+        bad[1] = "bps"[get - 1];
+        bail("missing parameter after ", bad);
+    }
+    if (arg == NULL)
+        return 0;
+
+    /* process long option or short options */
+    if (*arg == '-') {
+        /* a single dash will be interpreted as stdin */
+        if (*++arg == 0)
+            return 1;
+
+        /* process long option (fall through with equivalent short option) */
+        if (*arg == '-') {
+            int j;
+
+            arg++;
+            for (j = NLOPTS - 1; j >= 0; j--)
+                if (strcmp(arg, longopts[j][0]) == 0) {
+                    arg = longopts[j][1];
+                    break;
+                }
+            if (j < 0)
+                bail("invalid option: ", arg - 2);
+        }
+
+        /* process short options (more than one allowed after dash) */
+        do {
+            /* if looking for a parameter, don't process more single character
+               options until we have the parameter */
+            if (get) {
+                if (get == 3)
+                    bail("invalid usage: -s must be followed by space", "");
+                break;      /* allow -pnnn and -bnnn, fall to parameter code */
+            }
+
+            /* process next single character option */
+            bad[1] = *arg;
+            switch (*arg) {
+            case '0': case '1': case '2': case '3': case '4':
+            case '5': case '6': case '7': case '8': case '9':
+                level = *arg - '0';
+                new_opts();
+                break;
+            case 'K':  form = 2;  sufx = ".zip";  break;
+            case 'L':
+                fputs(VERSION, stderr);
+                fputs("Copyright (C) 2007, 2008, 2009, 2010 Mark Adler\n",
+                      stderr);
+                fputs("Subject to the terms of the zlib license.\n",
+                      stderr);
+                fputs("No warranty is provided or implied.\n", stderr);
+                exit(0);
+            case 'N':  headis = 3;  break;
+            case 'T':  headis &= ~2;  break;
+            case 'R':  rsync = 1;
+                bail("invalid option: rsyncable not implemented yet: ", bad);
+            case 'S':  get = 3;  break;
+            case 'V':  fputs(VERSION, stderr);  exit(0);
+            case 'Z':
+                bail("invalid option: LZW output not supported: ", bad);
+            case 'a':
+                bail("invalid option: ascii conversion not supported: ", bad);
+            case 'b':  get = 1;  break;
+            case 'c':  pipeout = 1;  break;
+            case 'd':  decode = 1;  headis = 0;  break;
+            case 'f':  force = 1;  break;
+            case 'h':  help();  break;
+            case 'i':  dict = 0;  break;
+            case 'k':  keep = 1;  break;
+            case 'l':  list = 1;  break;
+            case 'n':  headis &= ~1;  break;
+            case 'p':  get = 2;  break;
+            case 'q':  verbosity = 0;  break;
+            case 'r':  recurse = 1;  break;
+            case 't':  decode = 2;  break;
+            case 'v':  verbosity++;  break;
+            case 'z':  form = 1;  sufx = ".zz";  break;
+            default:
+                bail("invalid option: ", bad);
+            }
+        } while (*++arg);
+        if (*arg == 0)
+            return 0;
+    }
+
+    /* process option parameter for -b, -p, or -s */
+    if (get) {
+        size_t n;
+
+        if (get == 1) {
+            n = num(arg);
+            size = n << 10;                     /* chunk size */
+            if (size < DICT)
+                bail("block size too small (must be >= 32K)", "");
+            if (n != size >> 10 ||
+                size + (size >> 11) + 10 < size ||
+                (ssize_t)(size + (size >> 11) + 10) < 0)
+                bail("block size too large: ", arg);
+            new_opts();
+        }
+        else if (get == 2) {
+            n = num(arg);
+            procs = (int)n;                     /* # processes */
+            if (procs < 1)
+                bail("invalid number of processes: ", arg);
+            if ((size_t)procs != n || ((procs << 1) + 2) < 1)
+                bail("too many processes: ", arg);
+#ifdef NOTHREAD
+            if (procs > 1)
+                bail("this pigz compiled without threads", "");
+#endif
+            new_opts();
+        }
+        else if (get == 3)
+            sufx = arg;                         /* gz suffix */
+        get = 0;
+        return 0;
+    }
+
+    /* neither an option nor parameter */
+    return 1;
+}
+
+/* catch termination signal */
+local void cut_short(int sig)
+{
+    (void)sig;
+    Trace(("termination by user"));
+    if (outd != -1 && out != NULL)
+        unlink(out);
+    log_dump();
+    _exit(1);
+}
+
+/* Process arguments, compress in the gzip format.  Note that procs must be at
+   least two in order to provide a dictionary in one work unit for the other
+   work unit, and that size must be at least 32K to store a full dictionary. */
+int main(int argc, char **argv)
+{
+    int n;                          /* general index */
+    unsigned long done;             /* number of named files processed */
+    char *opts, *p;                 /* environment default options, marker */
+
+    /* prepare for interrupts and logging */
+    signal(SIGINT, cut_short);
+#ifndef NOTHREAD
+    yarn_prefix = "pigz";           /* prefix for yarn error messages */
+    yarn_abort = cut_short;         /* call on thread error */
+#endif
+#ifdef DEBUG
+    gettimeofday(&start, NULL);     /* starting time for log entries */
+    log_init();                     /* initialize logging */
+#endif
+
+    /* set all options to defaults */
+    defaults();
+
+    /* process user environment variable defaults */
+    opts = getenv("GZIP");
+    if (opts != NULL) {
+        while (*opts) {
+            while (*opts == ' ' || *opts == '\t')
+                opts++;
+            p = opts;
+            while (*p && *p != ' ' && *p != '\t')
+                p++;
+            n = *p;
+            *p = 0;
+            if (option(opts))
+                bail("cannot provide files in GZIP environment variable", "");
+            opts = p + (n ? 1 : 0);
+        }
+        option(NULL);
+    }
+
+    /* if no command line arguments and stdout is a terminal, show help */
+    if (argc < 2 && isatty(1))
+        help();
+
+    /* decompress if named "unpigz" or "gunzip" */
+    p = strrchr(argv[0], '/');
+    p = p == NULL ? argv[0] : p + 1;
+    if (strcmp(p, "unpigz") == 0 || strcmp(p, "gunzip") == 0)
+        decode = 1, headis = 0;
+
+    /* process command-line arguments */
+    done = 0;
+    for (n = 1; n < argc; n++)
+        if (option(argv[n])) {          /* true if file name, process it */
+            if (done == 1 && pipeout && !decode && !list && form > 1) {
+                fprintf(stderr, "warning: output is concatenated zip files ");
+                fprintf(stderr, "-- pigz will not be able to extract\n");
+            }
+            process(strcmp(argv[n], "-") ? argv[n] : NULL);
+            done++;
+        }
+    option(NULL);
+
+    /* list stdin or compress stdin to stdout if no file names provided */
+    if (done == 0)
+        process(NULL);
+
+    /* done -- release resources, show log */
+    new_opts();
+    log_dump();
+    return 0;
+}
diff --git a/pigz/pigz.spec b/pigz/pigz.spec
new file mode 100644
index 0000000..a29c202
--- /dev/null
+++ b/pigz/pigz.spec
@@ -0,0 +1,26 @@
+Summary: pigz is a parallel implementation of gzip which utilizes multiple cores
+Name: pigz
+Version: 2.1.6
+Release: 1
+Source0: %{name}-%{version}.tar.gz
+License: GPL
+Group: Applications/Tools
+Packager: Duncan Brown <duncan@duncanbrown.org>
+BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
+URL: http://www.zlib.net/pigz
+
+%description
+pigz, which stands for parallel implementation of gzip, is a fully functional replacement for gzip that exploits multiple processors and multiple cores to the hilt when compressing data. pigz was written by Mark Adler, and uses the zlib and pthread libraries.
+
+%clean
+rm -rf $RPM_BUILD_ROOT
+%prep
+mkdir -p $RPM_BUILD_ROOT
+%setup -q
+%build
+make
+mkdir -p ${RPM_BUILD_ROOT}/usr/bin
+mv pigz ${RPM_BUILD_ROOT}/usr/bin
+%files
+%defattr(-,root,root)
+/usr/bin/pigz
diff --git a/pigz/yarn.c b/pigz/yarn.c
new file mode 100644
index 0000000..0562e70
--- /dev/null
+++ b/pigz/yarn.c
@@ -0,0 +1,365 @@
+/* yarn.c -- generic thread operations implemented using pthread functions
+ * Copyright (C) 2008 Mark Adler
+ * Version 1.1  26 Oct 2008  Mark Adler
+ * For conditions of distribution and use, see copyright notice in yarn.h
+ */
+
+/* Basic thread operations implemented using the POSIX pthread library.  All
+   pthread references are isolated within this module to allow alternate
+   implementations with other thread libraries.  See yarn.h for the description
+   of these operations. */
+
+/* Version history:
+   1.0    19 Oct 2008  First version
+   1.1    26 Oct 2008  No need to set the stack size -- remove
+                       Add yarn_abort() function for clean-up on error exit
+ */
+
+/* for thread portability */
+#define _POSIX_PTHREAD_SEMANTICS
+#define _REENTRANT
+
+/* external libraries and entities referenced */
+#include <stdio.h>      /* fprintf(), stderr */
+#include <stdlib.h>     /* exit(), malloc(), free(), NULL */
+#include <pthread.h>    /* pthread_t, pthread_create(), pthread_join(), */
+    /* pthread_attr_t, pthread_attr_init(), pthread_attr_destroy(),
+       PTHREAD_CREATE_JOINABLE, pthread_attr_setdetachstate(),
+       pthread_self(), pthread_equal(),
+       pthread_mutex_t, PTHREAD_MUTEX_INITIALIZER, pthread_mutex_init(),
+       pthread_mutex_lock(), pthread_mutex_unlock(), pthread_mutex_destroy(),
+       pthread_cond_t, PTHREAD_COND_INITIALIZER, pthread_cond_init(),
+       pthread_cond_broadcast(), pthread_cond_wait(), pthread_cond_destroy() */
+#include <errno.h>      /* ENOMEM, EAGAIN, EINVAL */
+
+/* interface definition */
+#include "yarn.h"
+
+/* constants */
+#define local static            /* for non-exported functions and globals */
+
+/* error handling external globals, resettable by application */
+char *yarn_prefix = "yarn";
+void (*yarn_abort)(int) = NULL;
+
+
+/* immediately exit -- use for errors that shouldn't ever happen */
+local void fail(int err)
+{
+    fprintf(stderr, "%s: %s (%d) -- aborting\n", yarn_prefix,
+            err == ENOMEM ? "out of memory" : "internal pthread error", err);
+    if (yarn_abort != NULL)
+        yarn_abort(err);
+    exit(err == ENOMEM || err == EAGAIN ? err : EINVAL);
+}
+
+/* memory handling routines provided by user -- if none are provided, malloc()
+   and free() are used, which are therefore assumed to be thread-safe */
+typedef void *(*malloc_t)(size_t);
+typedef void (*free_t)(void *);
+local malloc_t my_malloc_f = malloc;
+local free_t my_free = free;
+
+/* use user-supplied allocation routines instead of malloc() and free() */
+void yarn_mem(malloc_t lease, free_t vacate)
+{
+    my_malloc_f = lease;
+    my_free = vacate;
+}
+
+/* memory allocation that cannot fail (from the point of view of the caller) */
+local void *my_malloc(size_t size)
+{
+    void *block;
+
+    if ((block = my_malloc_f(size)) == NULL)
+        fail(ENOMEM);
+    return block;
+}
+
+/* -- lock functions -- */
+
+struct lock_s {
+    pthread_mutex_t mutex;
+    pthread_cond_t cond;
+    long value;
+};
+
+lock *new_lock(long initial)
+{
+    int ret;
+    lock *bolt;
+
+    bolt = my_malloc(sizeof(struct lock_s));
+    if ((ret = pthread_mutex_init(&(bolt->mutex), NULL)) ||
+        (ret = pthread_cond_init(&(bolt->cond), NULL)))
+        fail(ret);
+    bolt->value = initial;
+    return bolt;
+}
+
+void possess(lock *bolt)
+{
+    int ret;
+
+    if ((ret = pthread_mutex_lock(&(bolt->mutex))) != 0)
+        fail(ret);
+}
+
+void release(lock *bolt)
+{
+    int ret;
+
+    if ((ret = pthread_mutex_unlock(&(bolt->mutex))) != 0)
+        fail(ret);
+}
+
+void twist(lock *bolt, enum twist_op op, long val)
+{
+    int ret;
+
+    if (op == TO)
+        bolt->value = val;
+    else if (op == BY)
+        bolt->value += val;
+    if ((ret = pthread_cond_broadcast(&(bolt->cond))) ||
+        (ret = pthread_mutex_unlock(&(bolt->mutex))))
+        fail(ret);
+}
+
+#define until(a) while(!(a))
+
+void wait_for(lock *bolt, enum wait_op op, long val)
+{
+    int ret;
+
+    switch (op) {
+    case TO_BE:
+        until (bolt->value == val)
+            if ((ret = pthread_cond_wait(&(bolt->cond), &(bolt->mutex))) != 0)
+                fail(ret);
+        break;
+    case NOT_TO_BE:
+        until (bolt->value != val)
+            if ((ret = pthread_cond_wait(&(bolt->cond), &(bolt->mutex))) != 0)
+                fail(ret);
+        break;
+    case TO_BE_MORE_THAN:
+        until (bolt->value > val)
+            if ((ret = pthread_cond_wait(&(bolt->cond), &(bolt->mutex))) != 0)
+                fail(ret);
+        break;
+    case TO_BE_LESS_THAN:
+        until (bolt->value < val)
+            if ((ret = pthread_cond_wait(&(bolt->cond), &(bolt->mutex))) != 0)
+                fail(ret);
+    }
+}
+
+long peek_lock(lock *bolt)
+{
+    return bolt->value;
+}
+
+void free_lock(lock *bolt)
+{
+    int ret;
+    if ((ret = pthread_cond_destroy(&(bolt->cond))) ||
+        (ret = pthread_mutex_destroy(&(bolt->mutex))))
+        fail(ret);
+    my_free(bolt);
+}
+
+/* -- thread functions (uses lock functions above) -- */
+
+struct thread_s {
+    pthread_t id;
+    int done;                   /* true if this thread has exited */
+    thread *next;               /* for list of all launched threads */
+};
+
+/* list of threads launched but not joined, count of threads exited but not
+   joined (incremented by ignition() just before exiting) */
+local lock threads_lock = {
+    PTHREAD_MUTEX_INITIALIZER,
+    PTHREAD_COND_INITIALIZER,
+    0                           /* number of threads exited but not joined */
+};
+local thread *threads = NULL;       /* list of extant threads */
+
+/* structure in which to pass the probe and its payload to ignition() */
+struct capsule {
+    void (*probe)(void *);
+    void *payload;
+};
+
+/* mark the calling thread as done and alert join_all() */
+local void reenter(void *dummy)
+{
+    thread *match, **prior;
+    pthread_t me;
+
+    /* find this thread in the threads list by matching the thread id */
+    me = pthread_self();
+    possess(&(threads_lock));
+    prior = &(threads);
+    while ((match = *prior) != NULL) {
+        if (pthread_equal(match->id, me))
+            break;
+        prior = &(match->next);
+    }
+    if (match == NULL)
+        fail(EINVAL);
+
+    /* mark this thread as done and move it to the head of the list */
+    match->done = 1;
+    if (threads != match) {
+        *prior = match->next;
+        match->next = threads;
+        threads = match;
+    }
+
+    /* update the count of threads to be joined and alert join_all() */
+    twist(&(threads_lock), BY, +1);
+}
+
+/* all threads go through this routine so that just before the thread exits,
+   it marks itself as done in the threads list and alerts join_all() so that
+   the thread resources can be released -- use cleanup stack so that the
+   marking occurs even if the thread is cancelled */
+local void *ignition(void *arg)
+{
+    struct capsule *capsule = arg;
+
+    /* run reenter() before leaving */
+    pthread_cleanup_push(reenter, NULL);
+
+    /* execute the requested function with argument */
+    capsule->probe(capsule->payload);
+    my_free(capsule);
+
+    /* mark this thread as done and let join_all() know */
+    pthread_cleanup_pop(1);
+
+    /* exit thread */
+    return NULL;
+}
+
+/* not all POSIX implementations create threads as joinable by default, so that
+   is made explicit here */
+thread *launch(void (*probe)(void *), void *payload)
+{
+    int ret;
+    thread *th;
+    struct capsule *capsule;
+    pthread_attr_t attr;
+
+    /* construct the requested call and argument for the ignition() routine
+       (allocated instead of automatic so that we're sure this will still be
+       there when ignition() actually starts up -- ignition() will free this
+       allocation) */
+    capsule = my_malloc(sizeof(struct capsule));
+    capsule->probe = probe;
+    capsule->payload = payload;
+
+    /* assure this thread is in the list before join_all() or ignition() looks
+       for it */
+    possess(&(threads_lock));
+
+    /* create the thread and call ignition() from that thread */
+    th = my_malloc(sizeof(struct thread_s));
+    if ((ret = pthread_attr_init(&attr)) ||
+        (ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE)) ||
+        (ret = pthread_create(&(th->id), &attr, ignition, capsule)) ||
+        (ret = pthread_attr_destroy(&attr)))
+        fail(ret);
+
+    /* put the thread in the threads list for join_all() */
+    th->done = 0;
+    th->next = threads;
+    threads = th;
+    release(&(threads_lock));
+    return th;
+}
+
+void join(thread *ally)
+{
+    int ret;
+    thread *match, **prior;
+
+    /* wait for thread to exit and return its resources */
+    if ((ret = pthread_join(ally->id, NULL)) != 0)
+        fail(ret);
+
+    /* find the thread in the threads list */
+    possess(&(threads_lock));
+    prior = &(threads);
+    while ((match = *prior) != NULL) {
+        if (match == ally)
+            break;
+        prior = &(match->next);
+    }
+    if (match == NULL)
+        fail(EINVAL);
+
+    /* remove thread from list and update exited count, free thread */
+    if (match->done)
+        threads_lock.value--;
+    *prior = match->next;
+    release(&(threads_lock));
+    my_free(ally);
+}
+
+/* This implementation of join_all() only attempts to join threads that have
+   announced that they have exited (see ignition()).  When there are many
+   threads, this is faster than waiting for some random thread to exit while a
+   bunch of other threads have already exited. */
+int join_all(void)
+{
+    int ret, count;
+    thread *match, **prior;
+
+    /* grab the threads list and initialize the joined count */
+    count = 0;
+    possess(&(threads_lock));
+
+    /* do until threads list is empty */
+    while (threads != NULL) {
+        /* wait until at least one thread has reentered */
+        wait_for(&(threads_lock), NOT_TO_BE, 0);
+
+        /* find the first thread marked done (should be at or near the top) */
+        prior = &(threads);
+        while ((match = *prior) != NULL) {
+            if (match->done)
+                break;
+            prior = &(match->next);
+        }
+        if (match == NULL)
+            fail(EINVAL);
+
+        /* join the thread (will be almost immediate), remove from the threads
+           list, update the reenter count, and free the thread */
+        if ((ret = pthread_join(match->id, NULL)) != 0)
+            fail(ret);
+        threads_lock.value--;
+        *prior = match->next;
+        my_free(match);
+        count++;
+    }
+
+    /* let go of the threads list and return the number of threads joined */
+    release(&(threads_lock));
+    return count;
+}
+
+/* cancel and join the thread -- the thread will cancel when it gets to a file
+   operation, a sleep or pause, or a condition wait */
+void destruct(thread *off_course)
+{
+    int ret;
+
+    if ((ret = pthread_cancel(off_course->id)) != 0)
+        fail(ret);
+    join(off_course);
+}
diff --git a/pigz/yarn.h b/pigz/yarn.h
new file mode 100644
index 0000000..7d99c7a
--- /dev/null
+++ b/pigz/yarn.h
@@ -0,0 +1,134 @@
+/* yarn.h -- generic interface for thread operations
+ * Copyright (C) 2008 Mark Adler
+ * Version 1.1  26 Oct 2008  Mark Adler
+ */
+
+/*
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the author be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+
+  Mark Adler
+  madler@alumni.caltech.edu
+ */
+
+/* Basic thread operations
+
+   This interface isolates the local operating system implementation of threads
+   from the application in order to facilitate platform independent use of
+   threads.  All of the implementation details are deliberately hidden.
+
+   Assuming adequate system resources and proper use, none of these functions
+   can fail.  As a result, any errors encountered will cause an exit() to be
+   executed.
+
+   These functions allow the simple launching and joining of threads, and the
+   locking of objects and synchronization of changes of objects.  The latter is
+   implemented with a single lock type that contains an integer value.  The
+   value can be ignored for simple exclusive access to an object, or the value
+   can be used to signal and wait for changes to an object.
+
+   -- Arguments --
+
+   thread *thread;          identifier for launched thread, used by join
+   void probe(void *);      pointer to function "probe", run when thread starts
+   void *payload;           single argument passed to the probe function
+   lock *lock;              a lock with a value -- used for exclusive access to
+                            an object and to synchronize threads waiting for
+                            changes to an object
+   long val;                value to set lock, increment lock, or wait for
+   int n;                   number of threads joined
+
+   -- Thread functions --
+
+   thread = launch(probe, payload) - launch a thread -- exit via probe() return
+   join(thread) - join a thread and by joining end it, waiting for the thread
+        to exit if it hasn't already -- will free the resources allocated by
+        launch() (don't try to join the same thread more than once)
+   n = join_all() - join all threads launched by launch() that are not joined
+        yet and free the resources allocated by the launches, usually to clean
+        up when the thread processing is done -- join_all() returns an int with
+        the count of the number of threads joined (join_all() should only be
+        called from the main thread, and should only be called after any calls
+        of join() have completed)
+   destruct(thread) - terminate the thread in mid-execution and join it
+        (depending on the implementation, the termination may not be immediate,
+        but may wait for the thread to execute certain thread or file i/o
+        operations)
+
+   -- Lock functions --
+
+   lock = new_lock(val) - create a new lock with initial value val (lock is
+        created in the released state)
+   possess(lock) - acquire exclusive possession of a lock, waiting if necessary
+   twist(lock, [TO | BY], val) - set lock to or increment lock by val, signal
+        all threads waiting on this lock and then release the lock -- must
+        possess the lock before calling (twist releases, so don't do a
+        release() after a twist() on the same lock)
+   wait_for(lock, [TO_BE | NOT_TO_BE | TO_BE_MORE_THAN | TO_BE_LESS_THAN], val)
+        - wait on lock value to be, not to be, be greater than, or be less than
+        val -- must possess the lock before calling, will possess the lock on
+        return but the lock is released while waiting to permit other threads
+        to use twist() to change the value and signal the change (so make sure
+        that the object is in a usable state when waiting)
+   release(lock) - release a possessed lock (do not try to release a lock that
+        the current thread does not possess)
+   val = peek_lock(lock) - return the value of the lock (assumes that lock is
+        already possessed, no possess or release is done by peek_lock())
+   free_lock(lock) - free the resources allocated by new_lock() (application
+        must assure that the lock is released before calling free_lock())
+
+   -- Memory allocation ---
+
+   yarn_mem(better_malloc, better_free) - set the memory allocation and free
+        routines for use by the yarn routines where the supplied routines have
+        the same interface and operation as malloc() and free(), and may be
+        provided in order to supply thread-safe memory allocation routines or
+        for any other reason -- by default malloc() and free() will be used
+
+   -- Error control --
+
+   yarn_name - a char pointer to a string that will be the prefix for any error
+        messages that these routines generate before exiting -- if not changed
+        by the application, "yarn" will be used
+   yarn_abort - an external function that will be executed when there is an
+        internal yarn error, due to out of memory or misuse -- this function
+        may exit to abort the application, or if it returns, the yarn error
+        handler will exit (set to NULL by default for no action)
+ */
+
+extern char *yarn_prefix;
+extern void (*yarn_abort)(int);
+
+void yarn_mem(void *(*)(size_t), void (*)(void *));
+
+typedef struct thread_s thread;
+thread *launch(void (*)(void *), void *);
+void join(thread *);
+int join_all(void);
+void destruct(thread *);
+
+typedef struct lock_s lock;
+lock *new_lock(long);
+void possess(lock *);
+void release(lock *);
+enum twist_op { TO, BY };
+void twist(lock *, enum twist_op, long);
+enum wait_op {
+    TO_BE, /* or */ NOT_TO_BE, /* that is the question */
+    TO_BE_MORE_THAN, TO_BE_LESS_THAN };
+void wait_for(lock *, enum wait_op, long);
+long peek_lock(lock *);
+void free_lock(lock *);