Merging upstream version 0.6.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

13 files changed, 383 insertions, 280 deletions

diff --git a/ChangeLog b/ChangeLog
index 127eba9..218c806 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2020-06-24  Antonio Diaz Diaz  <antonio@gnu.org>
+
+	* Version 0.6 released.
+	* Make '-o' behave like '-c', but writing to file instead of stdout.
+	* in_place.c: Multimember decompression should now work for any file
+	  that fits in memory and is smaller than (LONG_MAX - extra_bytes).
+	* README: Add an analysis of the in-place decompression.
+
 2020-04-27  Antonio Diaz Diaz  <antonio@gnu.org>
 
 	* Version 0.5 released.
diff --git a/INSTALL b/INSTALL
index c4b56f1..d6f1bc5 100644
--- a/INSTALL
+++ b/INSTALL
@@ -1,6 +1,6 @@
 Requirements
 ------------
-You will need a C compiler.
+You will need a C99 compiler. (gcc 2.95 or newer is recommended).
 I use gcc 6.1.0 and 4.1.2, but the code should compile with any standards
 compliant compiler.
 Gcc is available at http://gcc.gnu.org.
@@ -41,8 +41,8 @@ the main archive.
    documentation.
 
    Or type 'make install-compress', which additionally compresses the
-   man page after installation. (Installing compressed docs may become
-   the default in the future).
+   man page after installation.
+   (Installing compressed docs may become the default in the future).
 
    You can install only the program or the man page by typing
    'make install-bin' or 'make install-man' respectively.
diff --git a/Makefile.in b/Makefile.in
index 7bf71b7..1270170 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -71,7 +71,7 @@ install-info :
 	-rm -f "$(DESTDIR)$(infodir)/$(pkgname).info"*
 	$(INSTALL_DATA) $(VPATH)/doc/$(pkgname).info "$(DESTDIR)$(infodir)/$(pkgname).info"
 	-if $(CAN_RUN_INSTALLINFO) ; then \
-		install-info --info-dir="$(DESTDIR)$(infodir)" "$(DESTDIR)$(infodir)/$(pkgname).info" ; \
+	  install-info --info-dir="$(DESTDIR)$(infodir)" "$(DESTDIR)$(infodir)/$(pkgname).info" ; \
 	fi
 
 install-info-compress : install-info
@@ -96,7 +96,7 @@ uninstall-bin :
 
 uninstall-info :
 	-if $(CAN_RUN_INSTALLINFO) ; then \
-		install-info --info-dir="$(DESTDIR)$(infodir)" --remove "$(DESTDIR)$(infodir)/$(pkgname).info" ; \
+	  install-info --info-dir="$(DESTDIR)$(infodir)" --remove "$(DESTDIR)$(infodir)/$(pkgname).info" ; \
 	fi
 	-rm -f "$(DESTDIR)$(infodir)/$(pkgname).info"*
 
diff --git a/NEWS b/NEWS
index abe699b..e78dfd5 100644
--- a/NEWS
+++ b/NEWS
@@ -1,22 +1,19 @@
-Changes in version 0.5:
-
-The lzip_decompress module has been updated to version 5.4.18.
-
-Xlunzip now reports an error if a file name is empty (xlunzip -t "").
-
-The words 'decompressed' and 'compressed' have been replaced with the
-shorter 'out' and 'in' in the verbose output when decompressing or testing.
-
-Decompression speed has been slightly increased.
-
-A compilation error with GCC 10 has been fixed. (Reported by Daniel Baumann).
-
-The commands needed to extract files from a tar.lz archive have been
-documented in the output of '--help' and in the man page.
-
-Xlunzip now compiles on DOS with DJGPP. (Patch from Robert Riebisch).
-
-The configure script now accepts appending options to CFLAGS using the
-syntax 'CFLAGS+=OPTIONS'.
-
-9 new test files have been added to the testsuite.
+Changes in version 0.6:
+
+Option '-o, --output' now behaves like '-c, --stdout', but sending the
+output unconditionally to a file instead of to standard output. See the new
+description of '-o' in the manual. This change is not backwards compatible.
+Therefore commands like:
+  xlunzip -d -o foo - bar.lz < foo.lz
+must now be split into:
+  xlunzip -d -o foo - < foo.lz
+  xlunzip -d bar.lz
+or rewritten as:
+  xlunzip -d - bar.lz < foo.lz > foo
+
+In-place decompression of concatenated files should now work for any
+combination of files as long as they fit in memory and their total
+decompressed size is smaller than LONG_MAX minus a small extra space.
+
+The README file now includes an analysis of the amount of memory required
+for in-place decompression.
diff --git a/README b/README
index c5ebbf3..3e26a40 100644
--- a/README
+++ b/README
@@ -1,25 +1,23 @@
 Description
 
-Xlunzip is a test tool for the lzip decompression code of my lzip patch
-for linux. Xlunzip is similar to lunzip, but it uses the lzip_decompress
-linux module as a backend. Xlunzip tests the module for stream,
-buffer-to-buffer and mixed decompression modes, including in-place
-decompression (using the same buffer for input and output). You can use
-xlunzip to verify that the module produces correct results when
-decompressing single member files, multimember files, or the
-concatenation of two or more compressed files. Xlunzip can be used with
-unzcrash to test the robustness of the module to the decompression of
-corrupted data.
-
-Note that the in-place decompression of concatenated files can't be
-guaranteed to work because an arbitrarily low compression ratio of the
-last part of the data can be achieved by appending enough empty
-compressed members to a file, masking a high compression ratio at the
-beginning of the data.
-
-The xlunzip tarball contains a copy of the lzip_decompress module and
-can be compiled and tested without downloading or applying the patch to
-the kernel.
+Xlunzip is a test tool for the lzip decompression code of my lzip patch for
+linux. Xlunzip is similar to lunzip, but it uses the lzip_decompress linux
+module as a backend. Xlunzip tests the module for stream, buffer-to-buffer,
+and mixed decompression modes, including in-place decompression (using the
+same buffer for input and output). You can use xlunzip to verify that the
+module produces correct results when decompressing single member files,
+multimember files, or the concatenation of two or more compressed files.
+Xlunzip can be used with unzcrash to test the robustness of the module to
+the decompression of corrupted data.
+
+The distributed index feature of the lzip format allows xlunzip to
+decompress concatenated files in place. This can't be guaranteed to work
+with formats like gzip or bzip2 because they can't detect whether a high
+compression ratio in the first members of the multimember data is being
+masked by a low compression ratio in the last members.
+
+The xlunzip tarball contains a copy of the lzip_decompress module and can be
+compiled and tested without downloading or applying the patch to the kernel.
  
 My lzip patch for linux can be found at
 http://download.savannah.gnu.org/releases/lzip/kernel/
@@ -29,14 +27,72 @@ Lzip related components in the kernel
 
 The lzip_decompress module in lib/lzip_decompress.c provides a versatile
 lzip decompression function able to do buffer to buffer decompression or
-stream decompression with fill and flush callback functions. The usage
-of the function is documented in include/linux/lzip.h.
+stream decompression with fill and flush callback functions. The usage of
+the function is documented in include/linux/lzip.h.
 
 For decompressing the kernel image, initramfs, and initrd, there is a
 wrapper function in lib/decompress_lunzip.c providing the same common
 interface as the other decompress_*.c files, which is defined in
 include/linux/decompress/generic.h.
 
+Analysis of the in-place decompression
+======================================
+
+In order to decompress the kernel in place (using the same buffer for input
+and output), the compressed data is placed at the end of the buffer used to
+hold the decompressed data. The buffer must be large enough to contain after
+the decompressed data extra space for a marker, a trailer, the maximum
+possible data expansion, and (if the compressed data consists of more than
+one member) N-1 empty members.
+
+                 |------ compressed data ------|
+                 V                             V
+|----------------|-------------------|---------|
+^                                    ^  extra
+|-------- decompressed data ---------|
+
+The input pointer initially points to the beginning of the compressed data
+and the output pointer initially points to the beginning of the buffer.
+Decompressing compressible data reduces the distance between the pointers,
+while decompressing uncompressible data increases the distance. The extra
+space must be large enough that the output pointer does not overrun the
+input pointer even if all the overlap between compressed and decompressed
+data is uncompressible. The worst case is very compressible data followed by
+uncompressible data because in this case the output pointer increases faster
+when the input pointer is smaller.
+
+        |                        *   <-- input pointer
+        |                    *   ,   <-- output pointer
+        |                * ,  '
+        |            x  '            <-- overrun (x)
+memory  |        * ,'
+address |    *   ,'
+        |*     ,'
+        |    ,'
+        |  ,'
+        |,'
+        `--------------------------
+                    time
+
+All we need to know to calculate the minimum required extra space is:
+  The maximum expansion ratio.
+  The size of the last part of a member required to verify integrity.
+  For multimember data, the overhead per member. (36 bytes for lzip).
+
+The maximum expansion ratio of LZMA data is of about 1.4%. Rounding this up
+to 1/64 (1.5625%) and adding 36 bytes per input member, the extra space
+required to decompress lzip data in place is:
+  extra_bytes = ( compressed_size >> 6 ) + members * 36
+
+Using the compressed size to calculate the extra_bytes (as in the equation
+above) may slightly overestimate the amount of space required in the worst
+case. But calculating the extra_bytes from the uncompressed size (as does
+linux) is wrong (and inefficient for high compression ratios). The formula
+used in arch/x86/boot/header.S
+  extra_bytes = (uncompressed_size >> 8) + 65536
+fails with 1 MB of zeros followed by 8 MB of random data, and wastes memory
+for compression ratios > 4:1.
+
 
 Copyright (C) 2016-2020 Antonio Diaz Diaz.
 
diff --git a/carg_parser.c b/carg_parser.c
index 27d1a71..0f60878 100644
--- a/carg_parser.c
+++ b/carg_parser.c
@@ -1,20 +1,20 @@
-/*  Arg_parser - POSIX/GNU command line argument parser. (C version)
-    Copyright (C) 2006-2020 Antonio Diaz Diaz.
+/* Arg_parser - POSIX/GNU command line argument parser. (C version)
+   Copyright (C) 2006-2020 Antonio Diaz Diaz.
 
-    This library is free software. Redistribution and use in source and
-    binary forms, with or without modification, are permitted provided
-    that the following conditions are met:
+   This library is free software. Redistribution and use in source and
+   binary forms, with or without modification, are permitted provided
+   that the following conditions are met:
 
-    1. Redistributions of source code must retain the above copyright
-    notice, this list of conditions, and the following disclaimer.
+   1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions, and the following disclaimer.
 
-    2. Redistributions in binary form must reproduce the above copyright
-    notice, this list of conditions, and the following disclaimer in the
-    documentation and/or other materials provided with the distribution.
+   2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions, and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
 
-    This library is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 */
 
 #include <stdlib.h>
diff --git a/carg_parser.h b/carg_parser.h
index 60472ef..a442b7b 100644
--- a/carg_parser.h
+++ b/carg_parser.h
@@ -1,44 +1,44 @@
-/*  Arg_parser - POSIX/GNU command line argument parser. (C version)
-    Copyright (C) 2006-2020 Antonio Diaz Diaz.
+/* Arg_parser - POSIX/GNU command line argument parser. (C version)
+   Copyright (C) 2006-2020 Antonio Diaz Diaz.
 
-    This library is free software. Redistribution and use in source and
-    binary forms, with or without modification, are permitted provided
-    that the following conditions are met:
+   This library is free software. Redistribution and use in source and
+   binary forms, with or without modification, are permitted provided
+   that the following conditions are met:
 
-    1. Redistributions of source code must retain the above copyright
-    notice, this list of conditions, and the following disclaimer.
+   1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions, and the following disclaimer.
 
-    2. Redistributions in binary form must reproduce the above copyright
-    notice, this list of conditions, and the following disclaimer in the
-    documentation and/or other materials provided with the distribution.
+   2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions, and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
 
-    This library is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 */
 
-/*  Arg_parser reads the arguments in 'argv' and creates a number of
-    option codes, option arguments, and non-option arguments.
+/* Arg_parser reads the arguments in 'argv' and creates a number of
+   option codes, option arguments, and non-option arguments.
 
-    In case of error, 'ap_error' returns a non-null pointer to an error
-    message.
+   In case of error, 'ap_error' returns a non-null pointer to an error
+   message.
 
-    'options' is an array of 'struct ap_Option' terminated by an element
-    containing a code which is zero. A null name means a short-only
-    option. A code value outside the unsigned char range means a
-    long-only option.
+   'options' is an array of 'struct ap_Option' terminated by an element
+   containing a code which is zero. A null name means a short-only
+   option. A code value outside the unsigned char range means a
+   long-only option.
 
-    Arg_parser normally makes it appear as if all the option arguments
-    were specified before all the non-option arguments for the purposes
-    of parsing, even if the user of your program intermixed option and
-    non-option arguments. If you want the arguments in the exact order
-    the user typed them, call 'ap_init' with 'in_order' = true.
+   Arg_parser normally makes it appear as if all the option arguments
+   were specified before all the non-option arguments for the purposes
+   of parsing, even if the user of your program intermixed option and
+   non-option arguments. If you want the arguments in the exact order
+   the user typed them, call 'ap_init' with 'in_order' = true.
 
-    The argument '--' terminates all options; any following arguments are
-    treated as non-option arguments, even if they begin with a hyphen.
+   The argument '--' terminates all options; any following arguments are
+   treated as non-option arguments, even if they begin with a hyphen.
 
-    The syntax for optional option arguments is '-<short_option><argument>'
-    (without whitespace), or '--<long_option>=<argument>'.
+   The syntax for optional option arguments is '-<short_option><argument>'
+   (without whitespace), or '--<long_option>=<argument>'.
 */
 
 #ifdef __cplusplus
@@ -79,11 +79,11 @@ void ap_free( struct Arg_parser * const ap );
 
 const char * ap_error( const struct Arg_parser * const ap );
 
-    /* The number of arguments parsed (may be different from argc) */
+/* The number of arguments parsed. May be different from argc. */
 int ap_arguments( const struct Arg_parser * const ap );
 
-    /* If ap_code( i ) is 0, ap_argument( i ) is a non-option.
-       Else ap_argument( i ) is the option's argument (or empty). */
+/* If ap_code( i ) is 0, ap_argument( i ) is a non-option.
+   Else ap_argument( i ) is the option's argument (or empty). */
 int ap_code( const struct Arg_parser * const ap, const int i );
 
 const char * ap_argument( const struct Arg_parser * const ap, const int i );
diff --git a/configure b/configure
index 94a1ec9..da06771 100755
--- a/configure
+++ b/configure
@@ -6,7 +6,7 @@
 # to copy, distribute, and modify it.
 
 pkgname=xlunzip
-pkgversion=0.5
+pkgversion=0.6
 progname=xlunzip
 srctrigger=doc/${progname}.1
 
@@ -26,11 +26,7 @@ CFLAGS='-Wall -W -O2'
 LDFLAGS=
 
 # checking whether we are using GNU C.
-/bin/sh -c "${CC} --version" > /dev/null 2>&1 ||
-	{
-	CC=cc
-	CFLAGS=-O2
-	}
+/bin/sh -c "${CC} --version" > /dev/null 2>&1 || { CC=cc ; CFLAGS=-O2 ; }
 
 # Loop over all args
 args=
@@ -42,7 +38,8 @@ while [ $# != 0 ] ; do
 	shift
 
 	# Add the argument quoted to args
-	args="${args} \"${option}\""
+	if [ -z "${args}" ] ; then args="\"${option}\""
+	else args="${args} \"${option}\"" ; fi
 
 	# Split out the argument for options that take them
 	case ${option} in
diff --git a/doc/xlunzip.1 b/doc/xlunzip.1
index ea83510..2f7ccb1 100644
--- a/doc/xlunzip.1
+++ b/doc/xlunzip.1
@@ -1,27 +1,26 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.46.1.
-.TH XLUNZIP "1" "April 2020" "xlunzip 0.5" "User Commands"
+.TH XLUNZIP "1" "June 2020" "xlunzip 0.6" "User Commands"
 .SH NAME
 xlunzip \- test tool for the lzip_decompress linux module
 .SH SYNOPSIS
 .B xlunzip
 [\fI\,options\/\fR] [\fI\,files\/\fR]
 .SH DESCRIPTION
-Xlunzip is a test tool for the lzip decompression code of my lzip patch
-for linux. Xlunzip is similar to lunzip, but it uses the lzip_decompress
-linux module as a backend. Xlunzip tests the module for stream,
-buffer\-to\-buffer and mixed decompression modes, including in\-place
-decompression (using the same buffer for input and output). You can use
-xlunzip to verify that the module produces correct results when
-decompressing single member files, multimember files, or the
-concatenation of two or more compressed files. Xlunzip can be used with
-unzcrash to test the robustness of the module to the decompression of
-corrupted data.
+Xlunzip is a test tool for the lzip decompression code of my lzip patch for
+linux. Xlunzip is similar to lunzip, but it uses the lzip_decompress linux
+module as a backend. Xlunzip tests the module for stream, buffer\-to\-buffer,
+and mixed decompression modes, including in\-place decompression (using the
+same buffer for input and output). You can use xlunzip to verify that the
+module produces correct results when decompressing single member files,
+multimember files, or the concatenation of two or more compressed files.
+Xlunzip can be used with unzcrash to test the robustness of the module to
+the decompression of corrupted data.
 .PP
-Note that the in\-place decompression of concatenated files can't be
-guaranteed to work because an arbitrarily low compression ratio of the
-last part of the data can be achieved by appending enough empty
-compressed members to a file, masking a high compression ratio at the
-beginning of the data.
+The distributed index feature of the lzip format allows xlunzip to
+decompress concatenated files in place. This can't be guaranteed to work
+with formats like gzip or bzip2 because they can't detect whether a high
+compression ratio in the first members of the multimember data is being
+masked by a low compression ratio in the last members.
 .SH OPTIONS
 .TP
 \fB\-h\fR, \fB\-\-help\fR
@@ -46,7 +45,7 @@ decompress or test using only one buffer
 keep (don't delete) input files
 .TP
 \fB\-o\fR, \fB\-\-output=\fR<file>
-if reading standard input, write to <file>
+write to <file>, keep input files
 .TP
 \fB\-q\fR, \fB\-\-quiet\fR
 suppress all messages
diff --git a/in_place.c b/in_place.c
index 1ada24e..7f00933 100644
--- a/in_place.c
+++ b/in_place.c
@@ -1,18 +1,18 @@
-/*  Xlunzip - Test tool for the lzip_decompress linux module
-    Copyright (C) 2016-2020 Antonio Diaz Diaz.
+/* Xlunzip - Test tool for the lzip_decompress linux module
+   Copyright (C) 2016-2020 Antonio Diaz Diaz.
 
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 2 of the License, or
-    (at your option) any later version.
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 2 of the License, or
+   (at your option) any later version.
 
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
 
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #define _FILE_OFFSET_BITS 64
@@ -58,8 +58,7 @@ static uint8_t * read_file( const int infd, long * const buffer_sizep,
   {
   long buffer_size = 1 << 20;
   uint8_t * buffer = (uint8_t *)malloc( buffer_size );
-  if( !buffer )
-    { show_file_error( filename, "Not enough memory.", 0 ); return 0; }
+  if( !buffer ) { show_file_error( filename, mem_msg, 0 ); return 0; }
 
   long file_size = readblock( infd, buffer, buffer_size );
   while( file_size >= buffer_size && !errno )
@@ -70,8 +69,7 @@ static uint8_t * read_file( const int infd, long * const buffer_sizep,
     buffer_size = ( buffer_size <= LONG_MAX / 2 ) ? 2 * buffer_size : LONG_MAX;
     uint8_t * const tmp = (uint8_t *)realloc( buffer, buffer_size );
     if( !tmp )
-      { show_file_error( filename, "Not enough memory.", 0 ); free( buffer );
-        return 0; }
+      { show_file_error( filename, mem_msg, 0 ); free( buffer ); return 0; }
     buffer = tmp;
     file_size += readblock( infd, buffer + file_size, buffer_size - file_size );
     }
@@ -88,6 +86,7 @@ struct File_sizes
   {
   unsigned long long csize;
   unsigned long long dsize;
+  long members;
   long trailing;
   };
 
@@ -102,7 +101,8 @@ static const char * set_file_sizes( struct File_sizes * const file_sizes,
   if( !Lh_verify_version( *header ) )
     return "Version of lzip member format not supported.";
 
-  file_sizes->csize = file_sizes->dsize = file_sizes->trailing = 0;
+  file_sizes->csize = file_sizes->dsize = 0;
+  file_sizes->members = file_sizes->trailing = 0;
   unsigned long pos = file_size;	/* always points to a header or to EOF */
   while( pos >= min_member_size )
     {
@@ -137,6 +137,7 @@ static const char * set_file_sizes( struct File_sizes * const file_sizes,
     pos -= member_size;
     file_sizes->csize += member_size;
     file_sizes->dsize += Lt_get_data_size( *trailer );
+    ++file_sizes->members;
     }
   if( pos != 0 || file_sizes->csize == 0 ) return "Can't get file sizes.";
   if( file_sizes->csize + file_sizes->trailing != (unsigned long)file_size )
@@ -154,13 +155,15 @@ static void error(char *x) { show_file_error( global_name, x, 0 ); }
 /*
  * Load the compressed file at the end of the buffer used to hold the
  * decompressed data. Verify that the in-place decompression does not
- * overwrite the compressed data.
+ * overwrite the compressed data. The buffer must be large enough to contain
+ * after the decompressed data extra space for a marker, a trailer, the
+ * maximum possible data expansion, and (if multimember) N-1 empty members.
  *
- *                 |----- compressed data ------|
- *                 V                            V
- * |---------------|-------------------|--------|
- * ^                                   ^
- * |------- decompressed data ---------|
+ *                  |------ compressed data ------|
+ *                  V                             V
+ * |----------------|-------------------|---------|
+ * ^                                    ^  extra
+ * |-------- decompressed data ---------|
  */
 
 int decompress_in_place( const int infd, struct Pretty_print * const pp,
@@ -175,19 +178,22 @@ int decompress_in_place( const int infd, struct Pretty_print * const pp,
 
   const long csize = file_sizes.csize;
   const long dsize = file_sizes.dsize;
-  /* const long trailing = file_sizes.trailing; */
-  /* ( (csize-36+63) >> 6 ) + 36 never failed with single member */
-  const long rextra = ( csize >> 5 ) + 72;
-  if( buffer_size < dsize + rextra )	/* avoid realloc if big enough */
+/*  const long extra_bytes = ( dsize >> 8 ) + 65536; wrong linux formula */
+  const long extra_bytes = ( csize >> 6 ) + file_sizes.members * 36;
+  const long long target_buffer_size = max( dsize, csize ) + extra_bytes;
+  if( target_buffer_size > LONG_MAX )
+    { show_file_error( pp->name, "Buffer is larger than LONG_MAX.", 0 );
+      return 1; }
+  if( buffer_size < target_buffer_size )  /* avoid realloc if big enough */
     {
-    buffer_size = dsize + rextra;
-    buffer = (uint8_t *)realloc( buffer, buffer_size );
-    if( !buffer )
-      { show_file_error( pp->name, "Not enough memory.", 0 ); return 1; }
+    buffer = (uint8_t *)realloc( buffer, target_buffer_size );
+    if( !buffer ) { show_file_error( pp->name, mem_msg, 0 ); return 1; }
     }
-  else buffer_size = max( dsize + rextra, csize );
-  const long cbegin = buffer_size - csize;
+  buffer_size = target_buffer_size;
+  const long cbegin = buffer_size - csize;	/* overwrite trailing data */
   if( cbegin > 0 ) memmove( buffer + cbegin, buffer, csize );
+/*fprintf( stderr, "buffer_size = %ld, cbegin = %ld, extra_bytes = %ld\n",
+         buffer_size, cbegin, extra_bytes );*/
 
   long in_pos, out_pos;
   int retval;
diff --git a/lzip.h b/lzip.h
index 0840e35..f06c084 100644
--- a/lzip.h
+++ b/lzip.h
@@ -1,18 +1,18 @@
-/*  Xlunzip - Test tool for the lzip_decompress linux module
-    Copyright (C) 2016-2020 Antonio Diaz Diaz.
+/* Xlunzip - Test tool for the lzip_decompress linux module
+   Copyright (C) 2016-2020 Antonio Diaz Diaz.
 
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 2 of the License, or
-    (at your option) any later version.
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 2 of the License, or
+   (at your option) any later version.
 
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
 
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #ifndef max
@@ -75,6 +75,8 @@ static inline unsigned long long Lt_get_member_size( const Lzip_trailer data )
   }
 
 
+static const char * const mem_msg = "Not enough memory.";
+
 /* defined in in_place.c */
 int decompress_in_place( const int infd, struct Pretty_print * const pp,
                          const bool testing );
diff --git a/main.c b/main.c
index f267c15..0dc02c7 100644
--- a/main.c
+++ b/main.c
@@ -1,24 +1,24 @@
-/*  Xlunzip - Test tool for the lzip_decompress linux module
-    Copyright (C) 2016-2020 Antonio Diaz Diaz.
+/* Xlunzip - Test tool for the lzip_decompress linux module
+   Copyright (C) 2016-2020 Antonio Diaz Diaz.
 
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 2 of the License, or
-    (at your option) any later version.
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 2 of the License, or
+   (at your option) any later version.
 
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
 
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 /*
-    Exit status: 0 for a normal exit, 1 for environmental problems
-    (file not found, invalid flags, I/O errors, etc), 2 to indicate a
-    corrupt or invalid input file, 3 for an internal consistency error
-    (eg, bug) which caused xlunzip to panic.
+   Exit status: 0 for a normal exit, 1 for environmental problems
+   (file not found, invalid flags, I/O errors, etc), 2 to indicate a
+   corrupt or invalid input file, 3 for an internal consistency error
+   (eg, bug) which caused xlunzip to panic.
 */
 
 #define _FILE_OFFSET_BITS 64
@@ -94,21 +94,20 @@ static bool delete_output_on_interrupt = false;
 
 static void show_help( void )
   {
-  printf( "Xlunzip is a test tool for the lzip decompression code of my lzip patch\n"
-          "for linux. Xlunzip is similar to lunzip, but it uses the lzip_decompress\n"
-          "linux module as a backend. Xlunzip tests the module for stream,\n"
-          "buffer-to-buffer and mixed decompression modes, including in-place\n"
-          "decompression (using the same buffer for input and output). You can use\n"
-          "xlunzip to verify that the module produces correct results when\n"
-          "decompressing single member files, multimember files, or the\n"
-          "concatenation of two or more compressed files. Xlunzip can be used with\n"
-          "unzcrash to test the robustness of the module to the decompression of\n"
-          "corrupted data.\n"
-          "\nNote that the in-place decompression of concatenated files can't be\n"
-          "guaranteed to work because an arbitrarily low compression ratio of the\n"
-          "last part of the data can be achieved by appending enough empty\n"
-          "compressed members to a file, masking a high compression ratio at the\n"
-          "beginning of the data.\n"
+  printf( "Xlunzip is a test tool for the lzip decompression code of my lzip patch for\n"
+          "linux. Xlunzip is similar to lunzip, but it uses the lzip_decompress linux\n"
+          "module as a backend. Xlunzip tests the module for stream, buffer-to-buffer,\n"
+          "and mixed decompression modes, including in-place decompression (using the\n"
+          "same buffer for input and output). You can use xlunzip to verify that the\n"
+          "module produces correct results when decompressing single member files,\n"
+          "multimember files, or the concatenation of two or more compressed files.\n"
+          "Xlunzip can be used with unzcrash to test the robustness of the module to\n"
+          "the decompression of corrupted data.\n"
+          "\nThe distributed index feature of the lzip format allows xlunzip to\n"
+          "decompress concatenated files in place. This can't be guaranteed to work\n"
+          "with formats like gzip or bzip2 because they can't detect whether a high\n"
+          "compression ratio in the first members of the multimember data is being\n"
+          "masked by a low compression ratio in the last members.\n"
           "\nUsage: %s [options] [files]\n", invocation_name );
   printf( "\nOptions:\n"
           "  -h, --help                 display this help and exit\n"
@@ -118,7 +117,7 @@ static void show_help( void )
           "  -f, --force                overwrite existing output files\n"
           "  -I, --in-place             decompress or test using only one buffer\n"
           "  -k, --keep                 keep (don't delete) input files\n"
-          "  -o, --output=<file>        if reading standard input, write to <file>\n"
+          "  -o, --output=<file>        write to <file>, keep input files\n"
           "  -q, --quiet                suppress all messages\n"
           "  -t, --test                 test compressed file integrity\n"
           "  -v, --verbose              be verbose (a 2nd -v gives more)\n"
@@ -157,11 +156,7 @@ static void * resize_buffer( void * buf, const unsigned min_size )
   {
   if( buf ) buf = realloc( buf, min_size );
   else buf = malloc( min_size );
-  if( !buf )
-    {
-    show_error( "Not enough memory.", 0, false );
-    cleanup_and_fail( 1 );
-    }
+  if( !buf ) { show_error( mem_msg, 0, false ); cleanup_and_fail( 1 ); }
   return buf;
   }
 
@@ -316,7 +311,7 @@ static void set_d_outname( const char * const name, const int eindex )
 
 
 static int open_instream( const char * const name, struct stat * const in_statsp,
-                          const bool no_ofile )
+                          const bool one_to_one )
   {
   int infd = open( name, O_RDONLY | O_BINARY );
   if( infd < 0 )
@@ -328,13 +323,12 @@ static int open_instream( const char * const name, struct stat * const in_statsp
     const bool can_read = ( i == 0 &&
                             ( S_ISBLK( mode ) || S_ISCHR( mode ) ||
                               S_ISFIFO( mode ) || S_ISSOCK( mode ) ) );
-    if( i != 0 || ( !S_ISREG( mode ) && ( !can_read || !no_ofile ) ) )
+    if( i != 0 || ( !S_ISREG( mode ) && ( !can_read || one_to_one ) ) )
       {
       if( verbosity >= 0 )
         fprintf( stderr, "%s: Input file '%s' is not a regular file%s.\n",
-                 program_name, name,
-                 ( can_read && !no_ofile ) ?
-                 ",\n         and '--stdout' was not specified" : "" );
+                 program_name, name, ( can_read && one_to_one ) ?
+                 ",\n         and neither '-c' nor '-o' were specified" : "" );
       close( infd );
       infd = -1;
       }
@@ -343,11 +337,11 @@ static int open_instream( const char * const name, struct stat * const in_statsp
   }
 
 
-static bool open_outstream( const bool force, const bool from_stdin )
+static bool open_outstream( const bool force, const bool protect )
   {
   const mode_t usr_rw = S_IRUSR | S_IWUSR;
   const mode_t all_rw = usr_rw | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
-  const mode_t outfd_mode = from_stdin ? all_rw : usr_rw;
+  const mode_t outfd_mode = protect ? usr_rw : all_rw;
   int flags = O_APPEND | O_CREAT | O_RDWR | O_BINARY;
   if( force ) flags |= O_TRUNC; else flags |= O_EXCL;
 
@@ -399,7 +393,7 @@ static void signal_handler( int sig )
   }
 
 
-     /* Set permissions, owner, and times. */
+/* Set permissions, owner, and times. */
 static void close_and_set_permissions( const struct stat * const in_statsp )
   {
   bool warning = false;
@@ -499,7 +493,7 @@ static int decompress( struct Pretty_print * const pp, const long cl_insize,
   long in_pos, out_pos;
   int retval;
   if( ( in_len > 0 && !inbuf ) || ( out_size > 0 && !outbuf ) )
-    { show_error( "Not enough memory.", 0, false ); return 1; }
+    { show_error( mem_msg, 0, false ); return 1; }
 
   if( inbuf )
     {
@@ -544,6 +538,9 @@ void show_results( struct Pretty_print * const pp, const long in_pos,
   }
 
 
+static inline void set_retval( int * retval, const int new_val )
+  { if( *retval < new_val ) *retval = new_val; }
+
 static void show_error( const char * const msg, const int errcode,
                         const bool help )
   {
@@ -623,7 +620,7 @@ int main( const int argc, const char * const argv[] )
   if( argc > 0 ) invocation_name = argv[0];
 
   if( !ap_init( &parser, argc, argv, options, 0 ) )
-    { show_error( "Not enough memory.", 0, false ); return 1; }
+    { show_error( mem_msg, 0, false ); return 1; }
   if( ap_error( &parser ) )				/* bad option */
     { show_error( ap_error( &parser ), 0, true ); return 1; }
 
@@ -641,7 +638,8 @@ int main( const int argc, const char * const argv[] )
       case 'I': in_place = true; break;
       case 'k': keep_input_files = true; break;
       case 'n': break;
-      case 'o': default_output_filename = arg; break;
+      case 'o': if( strcmp( arg, "-" ) == 0 ) to_stdout = true;
+                else { default_output_filename = arg; } break;
       case 'q': verbosity = -1; break;
       case 't': testing = true; break;
       case 'v': if( verbosity < 4 ) ++verbosity; break;
@@ -672,64 +670,44 @@ int main( const int argc, const char * const argv[] )
     if( strcmp( filenames[i], "-" ) != 0 ) filenames_given = true;
     }
 
-  if( testing )
-    outfd = -1;
+  if( testing ) to_stdout = false;			/* apply overrides */
+  if( testing || to_stdout ) default_output_filename = "";
 
-  if( !to_stdout && !testing &&
-      ( filenames_given || default_output_filename[0] ) )
+  output_filename = resize_buffer( output_filename, 1 );
+  output_filename[0] = 0;
+  if( to_stdout && !testing ) outfd = STDOUT_FILENO;
+  else outfd = -1;
+
+  const bool to_file = !to_stdout && !testing && default_output_filename[0];
+  if( !to_stdout && !testing && ( filenames_given || to_file ) )
     set_signals( signal_handler );
 
   Pp_init( &pp, filenames, num_filenames );
 
-  output_filename = resize_buffer( output_filename, 1 );
+  const bool one_to_one = !to_stdout && !testing && !to_file;
   for( i = 0; i < num_filenames; ++i )
     {
     const char * input_filename = "";
     int tmp;
     struct stat in_stats;
     const struct stat * in_statsp;
-    output_filename[0] = 0;
 
     if( strcmp( filenames[i], "-" ) == 0 )
       {
       if( stdin_used ) continue; else stdin_used = true;
       infd = STDIN_FILENO;
-      if( !testing )
-        {
-        if( to_stdout || !default_output_filename[0] )
-          outfd = STDOUT_FILENO;
-        else
-          {
-          output_filename = resize_buffer( output_filename,
-                              strlen( default_output_filename ) + 1 );
-          strcpy( output_filename, default_output_filename );
-          if( !open_outstream( force, true ) )
-            {
-            if( retval < 1 ) retval = 1;
-            close( infd ); infd = -1;
-            continue;
-            }
-          }
-        }
+      if( one_to_one ) { outfd = STDOUT_FILENO; output_filename[0] = 0; }
       }
     else
       {
       input_filename = filenames[i];
-      infd = open_instream( input_filename, &in_stats, to_stdout || testing );
-      if( infd < 0 ) { if( retval < 1 ) retval = 1; continue; }
-      if( !testing )
+      infd = open_instream( input_filename, &in_stats, one_to_one );
+      if( infd < 0 ) { set_retval( &retval, 1 ); continue; }
+      if( one_to_one )
         {
-        if( to_stdout ) outfd = STDOUT_FILENO;
-        else
-          {
-          set_d_outname( input_filename, extension_index( input_filename ) );
-          if( !open_outstream( force, false ) )
-            {
-            if( retval < 1 ) retval = 1;
-            close( infd ); infd = -1;
-            continue;
-            }
-          }
+        set_d_outname( input_filename, extension_index( input_filename ) );
+        if( !open_outstream( force, true ) )
+          { set_retval( &retval, 1 ); close( infd ); infd = -1; continue; }
         }
       }
 
@@ -738,37 +716,43 @@ int main( const int argc, const char * const argv[] )
       {
       show_file_error( pp.name,
                        "I won't read compressed data from a terminal.", 0 );
-      if( retval < 1 ) retval = 1;
+      set_retval( &retval, 1 );
       if( testing ) { close( infd ); infd = -1; continue; }
       cleanup_and_fail( retval );
       }
 
-    in_statsp = input_filename[0] ? &in_stats : 0;
+    if( to_file && outfd < 0 )		/* open outfd after verifying infd */
+      {
+      output_filename = resize_buffer( output_filename,
+                        strlen( default_output_filename ) + 1 );
+      strcpy( output_filename, default_output_filename );
+      if( !open_outstream( force, false ) ) return 1;
+      }
+
+    in_statsp = ( input_filename[0] && one_to_one ) ? &in_stats : 0;
     if( in_place )
       tmp = decompress_in_place( infd, &pp, testing );
     else
       tmp = decompress( &pp, cl_insize, cl_outsize, nofill, noflush, testing );
     if( close( infd ) != 0 )
-      {
-      show_error( input_filename[0] ? "Error closing input file" :
-                                      "Error closing stdin", errno, false );
-      if( tmp < 1 ) tmp = 1;
-      }
+      { show_file_error( pp.name, "Error closing input file", errno );
+        set_retval( &tmp, 1 ); }
     infd = -1;
-    if( tmp > retval ) retval = tmp;
+    set_retval( &retval, tmp );
     if( tmp )
       { if( !testing ) cleanup_and_fail( retval );
         else ++failed_tests; }
 
-    if( delete_output_on_interrupt )
+    if( delete_output_on_interrupt && one_to_one )
       close_and_set_permissions( in_statsp );
-    if( input_filename[0] && !keep_input_files && !to_stdout && !testing )
+    if( input_filename[0] && !keep_input_files && one_to_one )
       remove( input_filename );
     }
-  if( outfd >= 0 && close( outfd ) != 0 )
+  if( delete_output_on_interrupt ) close_and_set_permissions( 0 );	/* -o */
+  else if( outfd >= 0 && close( outfd ) != 0 )				/* -c */
     {
     show_error( "Error closing stdout", errno, false );
-    if( retval < 1 ) retval = 1;
+    set_retval( &retval, 1 );
     }
   if( failed_tests > 0 && verbosity >= 1 && num_filenames > 1 )
     fprintf( stderr, "%s: warning: %d %s failed the test.\n",
diff --git a/testsuite/check.sh b/testsuite/check.sh
index 853deda..5625ac2 100755
--- a/testsuite/check.sh
+++ b/testsuite/check.sh
@@ -48,8 +48,13 @@ printf "testing xlunzip-%s..." "$2"
 [ $? = 2 ] || test_failed $LINENO
 "${LZIP}" -dq -o in < "${in_lz}"
 [ $? = 1 ] || test_failed $LINENO
+"${LZIP}" -dq -o in "${in_lz}"
+[ $? = 1 ] || test_failed $LINENO
+"${LZIP}" -dq -o out nx_file.lz
+[ $? = 1 ] || test_failed $LINENO
+[ ! -e out ] || test_failed $LINENO
 # these are for code coverage
-"${LZIP}" -t -- nx_file 2> /dev/null
+"${LZIP}" -t -- nx_file.lz 2> /dev/null
 [ $? = 1 ] || test_failed $LINENO
 "${LZIP}" -t "" < /dev/null 2> /dev/null
 [ $? = 1 ] || test_failed $LINENO
@@ -77,11 +82,17 @@ printf "\ntesting decompression..."
 
 for i in "${in_lz}" "${in_em}" ; do
 	"${LZIP}" -t "$i" || test_failed $LINENO "$i"
+	"${LZIP}" -d "$i" -o copy || test_failed $LINENO "$i"
+	cmp in copy || test_failed $LINENO "$i"
 	"${LZIP}" -cd "$i" > copy || test_failed $LINENO "$i"
 	cmp in copy || test_failed $LINENO "$i"
+	"${LZIP}" -d "$i" -o - > copy || test_failed $LINENO "$i"
+	cmp in copy || test_failed $LINENO "$i"
+	"${LZIP}" -d < "$i" > copy || test_failed $LINENO "$i"
+	cmp in copy || test_failed $LINENO "$i"
+	rm -f copy || framework_failure
 done
 
-rm -f copy || framework_failure
 cat "${in_lz}" > copy.lz || framework_failure
 "${LZIP}" -dk copy.lz || test_failed $LINENO
 cmp in copy || test_failed $LINENO
@@ -95,10 +106,16 @@ cmp in copy || test_failed $LINENO
 printf "to be overwritten" > copy || framework_failure
 "${LZIP}" -df -o copy < "${in_lz}" || test_failed $LINENO
 cmp in copy || test_failed $LINENO
+rm -f out copy || framework_failure
+"${LZIP}" -d -o ./- "${in_lz}" || test_failed $LINENO
+cmp in ./- || test_failed $LINENO
+rm -f ./- || framework_failure
+"${LZIP}" -d -o ./- < "${in_lz}" || test_failed $LINENO
+cmp in ./- || test_failed $LINENO
+rm -f ./- || framework_failure
 
-rm -f copy || framework_failure
 cat "${in_lz}" > anyothername || framework_failure
-"${LZIP}" -dv --output copy - anyothername - < "${in_lz}" 2> /dev/null ||
+"${LZIP}" -dv - anyothername - < "${in_lz}" > copy 2> /dev/null ||
 	test_failed $LINENO
 cmp in copy || test_failed $LINENO
 cmp in anyothername.out || test_failed $LINENO
@@ -128,12 +145,16 @@ cat "${in_lz}" > copy.lz || framework_failure
 cmp in copy || test_failed $LINENO
 
 cat in in > in2 || framework_failure
-cat "${in_lz}" "${in_lz}" > in2.lz || framework_failure
-"${LZIP}" -t in2.lz || test_failed $LINENO
-"${LZIP}" -cd in2.lz > copy2 || test_failed $LINENO
+"${LZIP}" -t "${in_lz}" "${in_lz}" || test_failed $LINENO
+"${LZIP}" -cd "${in_lz}" "${in_lz}" -o out > copy2 || test_failed $LINENO
+[ ! -e out ] || test_failed $LINENO			# override -o
+cmp in2 copy2 || test_failed $LINENO
+rm -f copy2 || framework_failure
+"${LZIP}" -d "${in_lz}" "${in_lz}" -o copy2 || test_failed $LINENO
 cmp in2 copy2 || test_failed $LINENO
+rm -f copy2 || framework_failure
 
-cat in2.lz > copy2.lz || framework_failure
+cat "${in_lz}" "${in_lz}" > copy2.lz || framework_failure
 printf "\ngarbage" >> copy2.lz || framework_failure
 "${LZIP}" -tvvvv copy2.lz 2> /dev/null || test_failed $LINENO
 printf "to be overwritten" > copy2 || framework_failure
@@ -183,6 +204,7 @@ for i in fox_bcrc.lz fox_crc0.lz fox_das46.lz fox_mes81.lz ; do
 done
 rm -f fox out || framework_failure
 
+cat "${in_lz}" "${in_lz}" > in2.lz || framework_failure
 cat "${in_lz}" "${in_lz}" "${in_lz}" > in3.lz || framework_failure
 if dd if=in3.lz of=trunc.lz bs=14752 count=1 2> /dev/null &&
    [ -e trunc.lz ] && cmp in2.lz trunc.lz > /dev/null 2>&1 ; then
@@ -283,30 +305,62 @@ cmp -s in copy && test_failed $LINENO
 [ $? = 1 ] || test_failed $LINENO
 cmp -s in copy && test_failed $LINENO
 
+# decompress in place
+rm -f copy copy2 || framework_failure
 "${LZIP}" -t --in-place "${in_lz}" || test_failed $LINENO
+"${LZIP}" -t --in-place < "${in_lz}" || test_failed $LINENO
+"${LZIP}" -d --in-place "${in_lz}" -o copy || test_failed $LINENO
+cmp in copy || test_failed $LINENO
+rm -f copy || framework_failure
+"${LZIP}" -d --in-place < "${in_lz}" -o copy || test_failed $LINENO
+cmp in copy || test_failed $LINENO
 "${LZIP}" -cd --in-place "${in_lz}" > copy || test_failed $LINENO
 cmp in copy || test_failed $LINENO
+"${LZIP}" -cd --in-place < "${in_lz}" > copy || test_failed $LINENO
+cmp in copy || test_failed $LINENO
+"${LZIP}" -t --in-place "${in_lz}" "${in_lz}" || test_failed $LINENO
+"${LZIP}" -d --in-place "${in_lz}" "${in_lz}" -o copy2 || test_failed $LINENO
+cmp in2 copy2 || test_failed $LINENO
+"${LZIP}" -cd --in-place "${in_lz}" "${in_lz}" > copy2 || test_failed $LINENO
+cmp in2 copy2 || test_failed $LINENO
+
+# decompress multimember in place
 cat in in in > in3 || framework_failure
 for i in in2 in3 ; do
 	"${LZIP}" -t --in-place $i.lz || test_failed $LINENO
+	"${LZIP}" -t --in-place < $i.lz || test_failed $LINENO
+	rm -f copy || framework_failure
+	"${LZIP}" -d --in-place $i.lz -o copy || test_failed $LINENO
+	cmp $i copy || test_failed $LINENO
+	rm -f copy || framework_failure
+	"${LZIP}" -d --in-place < $i.lz -o copy || test_failed $LINENO
+	cmp $i copy || test_failed $LINENO
 	"${LZIP}" -cd --in-place $i.lz > copy || test_failed $LINENO
 	cmp $i copy || test_failed $LINENO
+	"${LZIP}" -cd --in-place < $i.lz > copy || test_failed $LINENO
+	cmp $i copy || test_failed $LINENO
 done
 "${LZIP}" -tq --in-place ingin.lz
 [ $? = 2 ] || test_failed $LINENO
+rm -f copy copy2 ingin.lz in2 in2.lz in3 in3.lz || framework_failure
+
+cat "${in_lz}" > inz.lz || framework_failure
+counter=0
+while [ ${counter} -lt 20 ] ; do
+	cat "${zero_lz}" >> inz.lz || framework_failure
+	"${LZIP}" -t --in-place inz.lz || test_failed $LINENO
+	"${LZIP}" -cd --in-place inz.lz > copy || test_failed $LINENO
+	cmp in copy || test_failed $LINENO
+	counter=$((counter+1))
+done
+rm -f copy inz.lz || framework_failure
 
-cat "${in_lz}" "${zero_lz}" "${zero_lz}" "${zero_lz}" "${zero_lz}" \
-    "${zero_lz}" "${zero_lz}" "${zero_lz}" > inz.lz || framework_failure
-"${LZIP}" -t --in-place inz.lz || test_failed $LINENO
-"${LZIP}" -cd --in-place inz.lz > copy || test_failed $LINENO
+# decompress with trailing data in place
+cat "${in_lz}" in in in in > int.lz || framework_failure
+"${LZIP}" -t --in-place int.lz || test_failed $LINENO
+"${LZIP}" -cd --in-place int.lz > copy || test_failed $LINENO
 cmp in copy || test_failed $LINENO
-cat "${zero_lz}" >> inz.lz || framework_failure
-"${LZIP}" -tq --in-place inz.lz
-[ $? = 2 ] || test_failed $LINENO
-"${LZIP}" -cdq --in-place inz.lz > copy
-[ $? = 2 ] || test_failed $LINENO
-cmp -s in copy && test_failed $LINENO
-rm -f copy ingin.lz in2 in2.lz in3 in3.lz || framework_failure
+rm -f copy int.lz || framework_failure
 
 echo
 if [ ${fail} = 0 ] ; then