Merging upstream version 1.18~pre2.

Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>

18 files changed, 427 insertions, 220 deletions

diff --git a/ChangeLog b/ChangeLog
index 75abd30..835dec0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2015-09-16  Antonio Diaz Diaz  <antonio@gnu.org>
+
+	* Version 1.18-pre2 released.
+	* main.cc: Added new option '-a, --trailing-error'.
+	* Decompression time has been reduced by 2%.
+	* main.cc (decompress): Print up to 6 bytes of trailing data
+	  when '-tvvvv' is specified.
+	* range_dec.cc (list_file): Show dictionary size and size of
+	  trailing data (if any) with '-lv'.
+	* lzip.texi: Added chapter 'Trailing data'.
+	* testsuite/check.sh: Don't check error messages.
+
 2015-06-30  Antonio Diaz Diaz  <antonio@gnu.org>
 
 	* Version 1.18-pre1 released.
diff --git a/NEWS b/NEWS
index c46157d..4e36544 100644
--- a/NEWS
+++ b/NEWS
@@ -7,5 +7,21 @@ attempting to repair it.
 errors in these bytes sometimes can't be detected until the end of the
 member.
 
+The option "-a, --trailing-error", which makes lzip exit with error
+status 2 if any remaining input is detected after decompressing the last
+member, has been added.
+
 The new option "-x, --show-packets", which shows the LZMA packets
 (coding sequences) coded in a given file, has been added.
+
+Decompression time has been reduced by 2%.
+
+Up to 6 bytes of trailing data are printed when "-tvvvv" is specified.
+
+Dictionary size and size of trailing data (if any) are printed when
+"-lv" is specified.
+
+The new chapter "Trailing data" has been added to the manual.
+
+Fixed a harmless check failure on Windows caused by the failed
+comparison of a message in text mode.
diff --git a/configure b/configure
index aad4fc1..a76d668 100755
--- a/configure
+++ b/configure
@@ -6,7 +6,7 @@
 # to copy, distribute and modify it.
 
 pkgname=lziprecover
-pkgversion=1.18-pre1
+pkgversion=1.18-pre2
 progname=lziprecover
 srctrigger=doc/${pkgname}.texi
 
diff --git a/decoder.cc b/decoder.cc
index 5de3a6f..895bd9c 100644
--- a/decoder.cc
+++ b/decoder.cc
@@ -42,7 +42,7 @@ void Pretty_print::operator()( const char * const msg, FILE * const f ) const
       {
       first_post = false;
       std::fprintf( f, "  %s: ", name_.c_str() );
-      for( unsigned i = 0; i < longest_name - name_.size(); ++i )
+      for( unsigned i = name_.size(); i < longest_name; ++i )
         std::fputc( ' ', f );
       if( !msg ) std::fflush( f );
       }
@@ -62,7 +62,7 @@ long readblock( const int fd, uint8_t * const buf, const long size )
     {
     const int n = read( fd, buf + sz, std::min( 1L << 20, size - sz ) );
     if( n > 0 ) sz += n;
-    else if( n == 0 ) break;				/* EOF */
+    else if( n == 0 ) break;				// EOF
     else if( errno != EINTR ) break;
     errno = 0;
     }
@@ -117,7 +117,7 @@ void LZ_decoder::flush_data()
       if( s > 0 && writeblock( outfd, buffer + stream_pos + i, s ) != s )
         throw Error( "Write error" );
       }
-    if( pos >= buffer_size ) { partial_data_pos += pos; pos = 0; }
+    if( pos >= dictionary_size ) { partial_data_pos += pos; pos = 0; }
     stream_pos = pos;
     }
   }
@@ -206,9 +206,9 @@ int LZ_decoder::decode_member( const Pretty_print & pp )
   Bit_model bm_align[dis_align_size];
   Len_model match_len_model;
   Len_model rep_len_model;
-  unsigned rep0 = 0;		/* rep[0-3] latest four distances */
-  unsigned rep1 = 0;		/* used for efficient coding of */
-  unsigned rep2 = 0;		/* repeated distances */
+  unsigned rep0 = 0;		// rep[0-3] latest four distances
+  unsigned rep1 = 0;		// used for efficient coding of
+  unsigned rep2 = 0;		// repeated distances
   unsigned rep3 = 0;
   State state;
 
@@ -231,7 +231,7 @@ int LZ_decoder::decode_member( const Pretty_print & pp )
                                        peek( rep0 ) ) );
         }
       }
-    else					/* match or repeated match */
+    else					// match or repeated match
       {
       int len;
       if( rdec.decode_bit( bm_rep[state()] ) != 0 )		// 2nd bit
@@ -260,7 +260,7 @@ int LZ_decoder::decode_member( const Pretty_print & pp )
         state.set_rep();
         len = min_match_len + rdec.decode_len( rep_len_model, pos_state );
         }
-      else					/* match */
+      else					// match
         {
         const unsigned rep0_saved = rep0;
         len = min_match_len + rdec.decode_len( match_len_model, pos_state );
@@ -277,16 +277,16 @@ int LZ_decoder::decode_member( const Pretty_print & pp )
             {
             rep0 += rdec.decode( direct_bits - dis_align_bits ) << dis_align_bits;
             rep0 += rdec.decode_tree_reversed4( bm_align );
-            if( rep0 == 0xFFFFFFFFU )		/* marker found */
+            if( rep0 == 0xFFFFFFFFU )		// marker found
               {
               rep0 = rep0_saved;
               rdec.normalize();
               flush_data();
-              if( len == min_match_len )	/* End Of Stream marker */
+              if( len == min_match_len )	// End Of Stream marker
                 {
                 if( verify_trailer( pp ) ) return 0; else return 3;
                 }
-              if( len == min_match_len + 1 )	/* Sync Flush marker */
+              if( len == min_match_len + 1 )	// Sync Flush marker
                 {
                 rdec.load(); continue;
                 }
diff --git a/decoder.h b/decoder.h
index 5e6e16c..5ffc0be 100644
--- a/decoder.h
+++ b/decoder.h
@@ -19,12 +19,12 @@ class Range_decoder
   {
   enum { buffer_size = 16384 };
   unsigned long long partial_member_pos;
-  uint8_t * const buffer;	/* input buffer */
-  int pos;			/* current pos in buffer */
-  int stream_pos;		/* when reached, a new block must be read */
+  uint8_t * const buffer;	// input buffer
+  int pos;			// current pos in buffer
+  int stream_pos;		// when reached, a new block must be read
   uint32_t code;
   uint32_t range;
-  const int infd;		/* input file descriptor */
+  const int infd;		// input file descriptor
   bool at_stream_end;
 
   bool read_block();
@@ -214,12 +214,11 @@ class LZ_decoder
   unsigned long long partial_data_pos;
   Range_decoder & rdec;
   const unsigned dictionary_size;
-  const int buffer_size;
-  uint8_t * const buffer;	/* output buffer */
-  int pos;			/* current pos in buffer */
-  int stream_pos;		/* first byte not yet written to file */
+  uint8_t * const buffer;	// output buffer
+  unsigned pos;			// current pos in buffer
+  unsigned stream_pos;		// first byte not yet written to file
   uint32_t crc_;
-  const int outfd;		/* output file descriptor */
+  const int outfd;		// output file descriptor
 
   unsigned long long stream_position() const
     { return partial_data_pos + stream_pos; }
@@ -228,37 +227,42 @@ class LZ_decoder
 
   uint8_t peek_prev() const
     {
-    const int i = ( ( pos > 0 ) ? pos : buffer_size ) - 1;
+    const unsigned i = ( ( pos > 0 ) ? pos : dictionary_size ) - 1;
     return buffer[i];
     }
 
-  uint8_t peek( const int distance ) const
+  uint8_t peek( const unsigned distance ) const
     {
-    int i = pos - distance - 1;
-    if( i < 0 ) i += buffer_size;
+    unsigned i = pos - distance - 1;
+    if( pos <= distance ) i += dictionary_size;
     return buffer[i];
     }
 
   void put_byte( const uint8_t b )
     {
     buffer[pos] = b;
-    if( ++pos >= buffer_size ) flush_data();
+    if( ++pos >= dictionary_size ) flush_data();
     }
 
-  void copy_block( const int distance, int len )
+  void copy_block( const unsigned distance, unsigned len )
     {
-    int i = pos - distance - 1;
-    if( i < 0 ) i += buffer_size;
-    if( len < buffer_size - std::max( pos, i ) && len <= std::abs( pos - i ) )
+    unsigned i = pos - distance - 1;
+    bool fast;
+    if( pos <= distance )
+      { i += dictionary_size;
+        fast = ( len <= dictionary_size - i && len <= i - pos ); }
+    else
+      fast = ( len < dictionary_size - pos && len <= pos - i );
+    if( fast )					// no wrap, no overlap
       {
-      std::memcpy( buffer + pos, buffer + i, len );	// no wrap, no overlap
+      std::memcpy( buffer + pos, buffer + i, len );
       pos += len;
       }
     else for( ; len > 0; --len )
       {
       buffer[pos] = buffer[i];
-      if( ++pos >= buffer_size ) flush_data();
-      if( ++i >= buffer_size ) i = 0;
+      if( ++pos >= dictionary_size ) flush_data();
+      if( ++i >= dictionary_size ) i = 0;
       }
     }
 
@@ -275,13 +279,12 @@ public:
     partial_data_pos( 0 ),
     rdec( rde ),
     dictionary_size( header.dictionary_size() ),
-    buffer_size( std::max( 65536U, dictionary_size ) ),
-    buffer( new uint8_t[buffer_size] ),
+    buffer( new uint8_t[dictionary_size] ),
     pos( 0 ),
     stream_pos( 0 ),
     crc_( 0xFFFFFFFFU ),
     outfd( ofd )
-    { buffer[buffer_size-1] = 0; }	// prev_byte of first byte
+    { buffer[dictionary_size-1] = 0; }		// prev_byte of first byte
 
   ~LZ_decoder() { delete[] buffer; }
 
diff --git a/doc/lziprecover.1 b/doc/lziprecover.1
index 99b61dd..87c0598 100644
--- a/doc/lziprecover.1
+++ b/doc/lziprecover.1
@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.46.1.
-.TH LZIPRECOVER "1" "June 2015" "lziprecover 1.18-pre1" "User Commands"
+.TH LZIPRECOVER "1" "September 2015" "lziprecover 1.18-pre2" "User Commands"
 .SH NAME
 lziprecover \- recovers data from damaged lzip files
 .SH SYNOPSIS
@@ -23,6 +23,9 @@ display this help and exit
 \fB\-V\fR, \fB\-\-version\fR
 output version information and exit
 .TP
+\fB\-a\fR, \fB\-\-trailing\-error\fR
+exit with error status if trailing data
+.TP
 \fB\-c\fR, \fB\-\-stdout\fR
 send decompressed output to standard output
 .TP
diff --git a/doc/lziprecover.info b/doc/lziprecover.info
index 654e60c..8d7bc66 100644
--- a/doc/lziprecover.info
+++ b/doc/lziprecover.info
@@ -12,7 +12,7 @@ File: lziprecover.info,  Node: Top,  Next: Introduction,  Up: (dir)
 Lziprecover Manual
 ******************
 
-This manual is for Lziprecover (version 1.18-pre1, 30 June 2015).
+This manual is for Lziprecover (version 1.18-pre2, 16 September 2015).
 
 * Menu:
 
@@ -23,6 +23,7 @@ This manual is for Lziprecover (version 1.18-pre1, 30 June 2015).
 * Merging files::          Fixing several damaged copies
 * File names::             Names of the files produced by lziprecover
 * File format::            Detailed format of the compressed file
+* Trailing data::          Extra data appended to the file
 * Examples::               A small tutorial with examples
 * Unzcrash::               Testing the robustness of decompressors
 * Problems::               Reporting bugs
@@ -54,7 +55,7 @@ availability:
      recovery means. The lziprecover program can repair bit-flip errors
      (one of the most common forms of data corruption) in lzip files,
      and provides data recovery capabilities, including error-checked
-     merging of damaged copies of a file.
+     merging of damaged copies of a file. *Note Data safety::.
 
    * The lzip format is as simple as possible (but not simpler). The
      lzip manual provides the code of a simple decompressor along with
@@ -125,6 +126,13 @@ The format for running lziprecover is:
      Print the version number of lziprecover on the standard output and
      exit.
 
+'-a'
+'--trailing-error'
+     Exit with error status 2 if any remaining input is detected after
+     decompressing the last member. Such remaining input is usually
+     trailing garbage that can be safely ignored. *Note
+     concat-example::.
+
 '-c'
 '--stdout'
      Decompress to standard output. Needed when reading from a named
@@ -133,7 +141,9 @@ The format for running lziprecover is:
 
 '-d'
 '--decompress'
-     Decompress.
+     Decompress the specified file(s). If a file fails to decompress,
+     lziprecover exits immediately without decompressing the rest of the
+     files.
 
 '-D RANGE'
 '--range-decompress=RANGE'
@@ -220,7 +230,8 @@ The format for running lziprecover is:
      Check integrity of the specified file(s), but don't decompress
      them.  This really performs a trial decompression and throws away
      the result.  Use it together with '-v' to see information about
-     the file.
+     the file(s). If a file fails the test, lziprecover continues
+     checking the rest of the files.
 
 '-v'
 '--verbose'
@@ -228,7 +239,7 @@ The format for running lziprecover is:
      When decompressing or testing, further -v's (up to 4) increase the
      verbosity level, showing status, compression ratio, dictionary
      size, trailer contents (CRC, data size, member size), and up to 6
-     bytes of trailing garbage (if any).
+     bytes of trailing data (if any).
 
 
    Numbers given as arguments to options may be followed by a multiplier
@@ -387,7 +398,7 @@ original file name ends with one of the extensions '.tar.lz', '.lz' or
 '.tlz', the string '_fixed' is inserted before the extension.
 
 
-File: lziprecover.info,  Node: File format,  Next: Examples,  Prev: File names,  Up: Top
+File: lziprecover.info,  Node: File format,  Next: Trailing data,  Prev: File names,  Up: Top
 
 7 File format
 *************
@@ -421,7 +432,7 @@ additional information before, between, or after them.
 
    All multibyte values are stored in little endian order.
 
-'ID string'
+'ID string (the "magic" bytes)'
      A four byte string, identifying the lzip format, with the value
      "LZIP" (0x4C, 0x5A, 0x49, 0x50).
 
@@ -458,9 +469,42 @@ additional information before, between, or after them.
 
 
 
-File: lziprecover.info,  Node: Examples,  Next: Unzcrash,  Prev: File format,  Up: Top
+File: lziprecover.info,  Node: Trailing data,  Next: Examples,  Prev: File format,  Up: Top
+
+8 Extra data appended to the file
+*********************************
+
+Sometimes extra data is found appended to a lzip file after the last
+member. Such trailing data may be:
+
+   * Padding added to make the file size a multiple of some block size,
+     for example when writing to a tape.
+
+   * Garbage added by some not totally successful copy operation.
+
+   * Useful data added by the user; a cryptographically secure hash, a
+     description of file contents, etc.
+
+   * Malicious data added to the file in order to make its total size
+     and hash value (for a chosen hash) coincide with those of another
+     file.
+
+   * In very rare cases, trailing data could be the corrupt header of
+     another member. In multi-member or concatenated files the
+     probability of corruption happening in the magic bytes is 5 times
+     smaller than the probability of getting a false positive caused by
+     the corruption of the integrity information itself. Therefore it
+     can be considered to be below the noise level.
+
+   Trailing data can be safely ignored in most cases. In some cases,
+like user-added data, it is expected to be ignored. In those cases
+where a file containing trailing data must be rejected, the option
+'--trailing-error' can be used. *Note --trailing-error::.
+
+
+File: lziprecover.info,  Node: Examples,  Next: Unzcrash,  Prev: Trailing data,  Up: Top
 
-8 A small tutorial with examples
+9 A small tutorial with examples
 ********************************
 
 Example 1: Restore a regular file from its compressed version
@@ -475,29 +519,38 @@ show status.
      lziprecover -tv file.lz
 
 
-Example 3: Decompress 'file.lz' partially until 10 KiB of decompressed
+Example 3: The right way of concatenating compressed files.  *Note
+Trailing data::.
+
+     Don't do this
+       cat file1.lz file2.lz file3.lz | lziprecover -d
+     Do this instead
+       lziprecover -cd file1.lz file2.lz file3.lz
+
+
+Example 4: Decompress 'file.lz' partially until 10 KiB of decompressed
 data are produced.
 
      lziprecover -D 0,10KiB file.lz
 
 
-Example 4: Decompress 'file.lz' partially from decompressed byte 10000
+Example 5: Decompress 'file.lz' partially from decompressed byte 10000
 to decompressed byte 15000 (5000 bytes are produced).
 
      lziprecover -D 10000-15000 file.lz
 
 
-Example 5: Repair small errors in the file 'file.lz'. (Indented lines
+Example 6: Repair small errors in the file 'file.lz'. (Indented lines
 are abridged diagnostic messages from lziprecover).
 
      lziprecover -v -R file.lz
        Copy of input file repaired successfully.
      lziprecover -tv file_fixed.lz
-       ok
+       file_fixed.lz: ok
      mv file_fixed.lz file.lz
 
 
-Example 6: Split the multi-member file 'file.lz' and write each member
+Example 7: Split the multi-member file 'file.lz' and write each member
 in its own 'recXXXfile.lz' file. Then use 'lziprecover -t' to test the
 integrity of the resulting files.
 
@@ -505,26 +558,26 @@ integrity of the resulting files.
      lziprecover -tv rec*file.lz
 
 
-Example 7: Recover a compressed backup from two copies on CD-ROM with
-error-checked merging of copies (*Note GNU ddrescue manual:
+Example 8: Recover a compressed backup from two copies on CD-ROM with
+error-checked merging of copies.  (*Note GNU ddrescue manual:
 (ddrescue)Top, for details about ddrescue).
 
-     ddrescue -d -r1 -b2048 /dev/cdrom cdimage1 logfile1
+     ddrescue -d -r1 -b2048 /dev/cdrom cdimage1 mapfile1
      mount -t iso9660 -o loop,ro cdimage1 /mnt/cdimage
      cp /mnt/cdimage/backup.tar.lz rescued1.tar.lz
      umount /mnt/cdimage
        (insert second copy in the CD drive)
-     ddrescue -d -r1 -b2048 /dev/cdrom cdimage2 logfile2
+     ddrescue -d -r1 -b2048 /dev/cdrom cdimage2 mapfile2
      mount -t iso9660 -o loop,ro cdimage2 /mnt/cdimage
      cp /mnt/cdimage/backup.tar.lz rescued2.tar.lz
      umount /mnt/cdimage
      lziprecover -m -v -o backup.tar.lz rescued1.tar.lz rescued2.tar.lz
        Input files merged successfully.
      lziprecover -tv backup.tar.lz
-       ok
+       backup.tar.lz: ok
 
 
-Example 8: Recover the first volume of those created with the command
+Example 9: Recover the first volume of those created with the command
 'lzip -b 32MiB -S 650MB big_db' from two copies, 'big_db1_00001.lz' and
 'big_db2_00001.lz', with member 07 damaged in the first copy, member 18
 damaged in the second copy, and member 12 damaged in both copies. The
@@ -533,13 +586,13 @@ correct file produced is saved in 'big_db_00001.lz'.
      lziprecover -m -v -o big_db_00001.lz big_db1_00001.lz big_db2_00001.lz
        Input files merged successfully.
      lziprecover -tv big_db_00001.lz
-       ok
+       big_db_00001.lz: ok
 
 
 File: lziprecover.info,  Node: Unzcrash,  Next: Problems,  Prev: Examples,  Up: Top
 
-9 Testing the robustness of decompressors
-*****************************************
+10 Testing the robustness of decompressors
+******************************************
 
 The lziprecover package also includes unzcrash, a program written to
 test robustness to decompression of corrupted data, inspired by
@@ -615,7 +668,7 @@ caused unzcrash to panic.
 
 File: lziprecover.info,  Node: Problems,  Next: Concept index,  Prev: Unzcrash,  Up: Top
 
-10 Reporting bugs
+11 Reporting bugs
 *****************
 
 There are probably bugs in lziprecover. There are certainly errors and
@@ -646,24 +699,28 @@ Concept index
 * invoking:                              Invoking lziprecover.  (line 6)
 * merging files:                         Merging files.         (line 6)
 * repairing files:                       Repairing files.       (line 6)
+* trailing data:                         Trailing data.         (line 6)
 * unzcrash:                              Unzcrash.              (line 6)
 
 
 
 Tag Table:
 Node: Top231
-Node: Introduction1214
-Node: Invoking lziprecover4310
-Node: Data safety9743
-Node: Repairing files11667
-Node: Merging files13569
-Node: File names15410
-Node: File format15874
-Node: Examples18278
-Ref: ddrescue-example19524
-Node: Unzcrash20780
-Node: Problems23334
-Node: Concept index23886
+Node: Introduction1278
+Node: Invoking lziprecover4395
+Ref: --trailing-error4860
+Node: Data safety10294
+Node: Repairing files12218
+Node: Merging files14120
+Node: File names15961
+Node: File format16425
+Node: Trailing data18854
+Node: Examples20230
+Ref: concat-example20661
+Ref: ddrescue-example21725
+Node: Unzcrash23015
+Node: Problems25571
+Node: Concept index26123
 
 End Tag Table
 
diff --git a/doc/lziprecover.texi b/doc/lziprecover.texi
index 29045e7..e29a59f 100644
--- a/doc/lziprecover.texi
+++ b/doc/lziprecover.texi
@@ -6,8 +6,8 @@
 @finalout
 @c %**end of header
 
-@set UPDATED 30 June 2015
-@set VERSION 1.18-pre1
+@set UPDATED 16 September 2015
+@set VERSION 1.18-pre2
 
 @dircategory Data Compression
 @direntry
@@ -42,6 +42,7 @@ This manual is for Lziprecover (version @value{VERSION}, @value{UPDATED}).
 * Merging files::          Fixing several damaged copies
 * File names::             Names of the files produced by lziprecover
 * File format::            Detailed format of the compressed file
+* Trailing data::          Extra data appended to the file
 * Examples::               A small tutorial with examples
 * Unzcrash::               Testing the robustness of decompressors
 * Problems::               Reporting bugs
@@ -75,7 +76,7 @@ The lzip format provides very safe integrity checking and some data
 recovery means. The lziprecover program can repair bit-flip errors (one
 of the most common forms of data corruption) in lzip files, and provides
 data recovery capabilities, including error-checked merging of damaged
-copies of a file.
+copies of a file. @xref{Data safety}.
 
 @item
 The lzip format is as simple as possible (but not simpler). The lzip
@@ -152,6 +153,13 @@ Print an informative help message describing the options and exit.
 @itemx --version
 Print the version number of lziprecover on the standard output and exit.
 
+@anchor{--trailing-error}
+@item -a
+@itemx --trailing-error
+Exit with error status 2 if any remaining input is detected after
+decompressing the last member. Such remaining input is usually trailing
+garbage that can be safely ignored. @xref{concat-example}.
+
 @item -c
 @itemx --stdout
 Decompress to standard output. Needed when reading from a named pipe
@@ -160,7 +168,9 @@ data as possible when decompressing a corrupt file.
 
 @item -d
 @itemx --decompress
-Decompress.
+Decompress the specified file(s). If a file fails to decompress,
+lziprecover exits immediately without decompressing the rest of the
+files.
 
 @item -D @var{range}
 @itemx --range-decompress=@var{range}
@@ -246,7 +256,9 @@ on the number of members in @samp{@var{file}}.
 @itemx --test
 Check integrity of the specified file(s), but don't decompress them.
 This really performs a trial decompression and throws away the result.
-Use it together with @samp{-v} to see information about the file.
+Use it together with @samp{-v} to see information about the file(s). If
+a file fails the test, lziprecover continues checking the rest of the
+files.
 
 @item -v
 @itemx --verbose
@@ -254,7 +266,7 @@ Verbose mode.@*
 When decompressing or testing, further -v's (up to 4) increase the
 verbosity level, showing status, compression ratio, dictionary size,
 trailer contents (CRC, data size, member size), and up to 6 bytes of
-trailing garbage (if any).
+trailing data (if any).
 
 @end table
 
@@ -456,7 +468,7 @@ Each member has the following structure:
 All multibyte values are stored in little endian order.
 
 @table @samp
-@item ID string
+@item ID string (the "magic" bytes)
 A four byte string, identifying the lzip format, with the value "LZIP"
 (0x4C, 0x5A, 0x49, 0x50).
 
@@ -499,6 +511,44 @@ facilitates safe recovery of undamaged members from multi-member files.
 @end table
 
 
+@node Trailing data
+@chapter Extra data appended to the file
+@cindex trailing data
+
+Sometimes extra data is found appended to a lzip file after the last
+member. Such trailing data may be:
+
+@itemize @bullet
+@item
+Padding added to make the file size a multiple of some block size, for
+example when writing to a tape.
+
+@item
+Garbage added by some not totally successful copy operation.
+
+@item
+Useful data added by the user; a cryptographically secure hash, a
+description of file contents, etc.
+
+@item
+Malicious data added to the file in order to make its total size and
+hash value (for a chosen hash) coincide with those of another file.
+
+@item
+In very rare cases, trailing data could be the corrupt header of another
+member. In multi-member or concatenated files the probability of
+corruption happening in the magic bytes is 5 times smaller than the
+probability of getting a false positive caused by the corruption of the
+integrity information itself. Therefore it can be considered to be below
+the noise level.
+@end itemize
+
+Trailing data can be safely ignored in most cases. In some cases, like
+user-added data, it is expected to be ignored. In those cases where a
+file containing trailing data must be rejected, the option
+@samp{--trailing-error} can be used. @xref{--trailing-error}.
+
+
 @node Examples
 @chapter A small tutorial with examples
 @cindex examples
@@ -521,8 +571,21 @@ lziprecover -tv file.lz
 @end example
 
 @sp 1
+@anchor{concat-example}
+@noindent
+Example 3: The right way of concatenating compressed files.
+@xref{Trailing data}.
+
+@example
+Don't do this
+  cat file1.lz file2.lz file3.lz | lziprecover -d
+Do this instead
+  lziprecover -cd file1.lz file2.lz file3.lz
+@end example
+
+@sp 1
 @noindent
-Example 3: Decompress @samp{file.lz} partially until 10 KiB of
+Example 4: Decompress @samp{file.lz} partially until 10 KiB of
 decompressed data are produced.
 
 @example
@@ -531,7 +594,7 @@ lziprecover -D 0,10KiB file.lz
 
 @sp 1
 @noindent
-Example 4: Decompress @samp{file.lz} partially from decompressed byte
+Example 5: Decompress @samp{file.lz} partially from decompressed byte
 10000 to decompressed byte 15000 (5000 bytes are produced).
 
 @example
@@ -540,20 +603,20 @@ lziprecover -D 10000-15000 file.lz
 
 @sp 1
 @noindent
-Example 5: Repair small errors in the file @samp{file.lz}. (Indented
+Example 6: Repair small errors in the file @samp{file.lz}. (Indented
 lines are abridged diagnostic messages from lziprecover).
 
 @example
 lziprecover -v -R file.lz
   Copy of input file repaired successfully.
 lziprecover -tv file_fixed.lz
-  ok
+  file_fixed.lz: ok
 mv file_fixed.lz file.lz
 @end example
 
 @sp 1
 @noindent
-Example 6: Split the multi-member file @samp{file.lz} and write each
+Example 7: Split the multi-member file @samp{file.lz} and write each
 member in its own @samp{recXXXfile.lz} file. Then use
 @w{@samp{lziprecover -t}} to test the integrity of the resulting files.
 
@@ -565,8 +628,8 @@ lziprecover -tv rec*file.lz
 @sp 1
 @anchor{ddrescue-example}
 @noindent
-Example 7: Recover a compressed backup from two copies on CD-ROM with
-error-checked merging of copies
+Example 8: Recover a compressed backup from two copies on CD-ROM with
+error-checked merging of copies.
 @ifnothtml
 (@xref{Top,GNU ddrescue manual,,ddrescue},
 @end ifnothtml
@@ -577,24 +640,24 @@ error-checked merging of copies
 for details about ddrescue).
 
 @example
-ddrescue -d -r1 -b2048 /dev/cdrom cdimage1 logfile1
+ddrescue -d -r1 -b2048 /dev/cdrom cdimage1 mapfile1
 mount -t iso9660 -o loop,ro cdimage1 /mnt/cdimage
 cp /mnt/cdimage/backup.tar.lz rescued1.tar.lz
 umount /mnt/cdimage
   (insert second copy in the CD drive)
-ddrescue -d -r1 -b2048 /dev/cdrom cdimage2 logfile2
+ddrescue -d -r1 -b2048 /dev/cdrom cdimage2 mapfile2
 mount -t iso9660 -o loop,ro cdimage2 /mnt/cdimage
 cp /mnt/cdimage/backup.tar.lz rescued2.tar.lz
 umount /mnt/cdimage
 lziprecover -m -v -o backup.tar.lz rescued1.tar.lz rescued2.tar.lz
   Input files merged successfully.
 lziprecover -tv backup.tar.lz
-  ok
+  backup.tar.lz: ok
 @end example
 
 @sp 1
 @noindent
-Example 8: Recover the first volume of those created with the command
+Example 9: Recover the first volume of those created with the command
 @w{@samp{lzip -b 32MiB -S 650MB big_db}} from two copies,
 @samp{big_db1_00001.lz} and @samp{big_db2_00001.lz}, with member 07
 damaged in the first copy, member 18 damaged in the second copy, and
@@ -605,7 +668,7 @@ member 12 damaged in both copies. The correct file produced is saved in
 lziprecover -m -v -o big_db_00001.lz big_db1_00001.lz big_db2_00001.lz
   Input files merged successfully.
 lziprecover -tv big_db_00001.lz
-  ok
+  big_db_00001.lz: ok
 @end example
 
 
diff --git a/file_index.cc b/file_index.cc
index a1a0f30..af55417 100644
--- a/file_index.cc
+++ b/file_index.cc
@@ -86,7 +86,7 @@ File_index::File_index( const int infd )
     if( member_size < min_member_size || member_size > pos )
       {
       if( member_vector.empty() )
-        { --pos; continue; }			// maybe trailing garbage
+        { --pos; continue; }			// maybe trailing data
       set_num_error( "Member size in trailer is corrupt at pos ", pos - 8 );
       break;
       }
@@ -96,10 +96,11 @@ File_index::File_index( const int infd )
     if( !header.verify_magic() || !header.verify_version() )
       {
       if( member_vector.empty() )
-        { --pos; continue; }			// maybe trailing garbage
+        { --pos; continue; }			// maybe trailing data
       set_num_error( "Bad header at pos ", pos - member_size );
       break;
       }
+    const unsigned dictionary_size = header.dictionary_size();
     if( member_vector.empty() && isize - pos > File_header::size &&
         seek_read( infd, header.data, File_header::size, pos ) == File_header::size &&
         header.verify_magic() && header.verify_version() )
@@ -109,7 +110,7 @@ File_index::File_index( const int infd )
       }
     pos -= member_size;
     member_vector.push_back( Member( 0, trailer.data_size(),
-                                     pos, member_size ) );
+                                     pos, member_size, dictionary_size ) );
     }
   if( pos != 0 || member_vector.empty() )
     {
@@ -184,7 +185,7 @@ File_index::File_index( const std::vector< int > & infd_vector,
       }
     if( !done )
       {
-      if( member_vector.empty() )		// maybe trailing garbage
+      if( member_vector.empty() )		// maybe trailing data
         { --pos; continue; }
       set_num_error( "Member size in trailer may be corrupt at pos ", pos - 8 );
       break;
@@ -202,7 +203,7 @@ File_index::File_index( const std::vector< int > & infd_vector,
         }
     pos -= member_size;
     member_vector.push_back( Member( 0, trailer.data_size(),
-                                     pos, member_size ) );
+                                     pos, member_size, 0 ) );
     }
 error:
   if( pos != 0 || member_vector.empty() )
diff --git a/file_index.h b/file_index.h
index eff1157..5084fcb 100644
--- a/file_index.h
+++ b/file_index.h
@@ -20,10 +20,11 @@ class File_index
   struct Member
     {
     Block dblock, mblock;		// data block, member block
+    unsigned dictionary_size;
 
     Member( const long long dp, const long long ds,
-            const long long mp, const long long ms )
-      : dblock( dp, ds ), mblock( mp, ms ) {}
+            const long long mp, const long long ms, const unsigned dict_size )
+      : dblock( dp, ds ), mblock( mp, ms ), dictionary_size( dict_size ) {}
 
     bool operator==( const Member & m ) const { return ( mblock == m.mblock ); }
     bool operator!=( const Member & m ) const { return ( mblock != m.mblock ); }
@@ -36,10 +37,10 @@ class File_index
 
   void set_errno_error( const char * const msg );
   void set_num_error( const char * const msg1, unsigned long long num,
-                      const char * const msg2 = "." );
+                      const char * const msg2 = "" );
 
 public:
-  File_index() : error_( "No index." ), isize( 0 ), retval_( 2 ) {}
+  File_index() : error_( "No index" ), isize( 0 ), retval_( 2 ) {}
   explicit File_index( const int infd );
   File_index( const std::vector< int > & infd_vector, const long long fsize );
 
@@ -65,7 +66,7 @@ public:
     { if( member_vector.size() ) return member_vector.back().mblock.end();
       else return 0; }
 
-  // total size including trailing garbage (if any)
+  // total size including trailing data (if any)
   long long file_size() const
     { if( isize >= 0 ) return isize; else return 0; }
 
@@ -73,4 +74,6 @@ public:
     { return member_vector[i].dblock; }
   const Block & mblock( const long i ) const
     { return member_vector[i].mblock; }
+  unsigned dictionary_size( const long i ) const
+    { return member_vector[i].dictionary_size; }
   };
diff --git a/lzip.h b/lzip.h
index e46b9b8..3bdc27c 100644
--- a/lzip.h
+++ b/lzip.h
@@ -40,7 +40,7 @@ public:
 
 enum {
   min_dictionary_bits = 12,
-  min_dictionary_size = 1 << min_dictionary_bits,	/* >= modeled_distances */
+  min_dictionary_size = 1 << min_dictionary_bits,	// >= modeled_distances
   max_dictionary_bits = 29,
   max_dictionary_size = 1 << max_dictionary_bits,
   min_member_size = 36,
@@ -53,7 +53,7 @@ enum {
   dis_slot_bits = 6,
   start_dis_model = 4,
   end_dis_model = 14,
-  modeled_distances = 1 << (end_dis_model / 2),		/* 128 */
+  modeled_distances = 1 << (end_dis_model / 2),		// 128
   dis_align_bits = 4,
   dis_align_size = 1 << dis_align_bits,
 
@@ -65,8 +65,8 @@ enum {
   len_high_symbols = 1 << len_high_bits,
   max_len_symbols = len_low_symbols + len_mid_symbols + len_high_symbols,
 
-  min_match_len = 2,					/* must be 2 */
-  max_match_len = min_match_len + max_len_symbols - 1,	/* 273 */
+  min_match_len = 2,					// must be 2
+  max_match_len = min_match_len + max_len_symbols - 1,	// 273
   min_match_len_limit = 5 };
 
 inline int get_len_state( const int len )
@@ -109,6 +109,7 @@ public:
     : stdin_name( "(stdin)" ), longest_name( 0 ), verbosity_( v ),
       first_post( false )
     {
+    if( verbosity_ <= 0 ) return;
     const unsigned stdin_name_len = std::strlen( stdin_name );
     for( unsigned i = 0; i < filenames.size(); ++i )
       {
@@ -186,9 +187,9 @@ const uint8_t magic_string[4] = { 0x4C, 0x5A, 0x49, 0x50 };	// "LZIP"
 
 struct File_header
   {
-  uint8_t data[6];			/* 0-3 magic bytes */
-					/*   4 version */
-					/*   5 coded_dict_size */
+  uint8_t data[6];			// 0-3 magic bytes
+					//   4 version
+					//   5 coded_dict_size
   enum { size = 6 };
 
   void set_magic() { std::memcpy( data, magic_string, 4 ); data[4] = 1; }
@@ -228,9 +229,9 @@ struct File_header
 
 struct File_trailer
   {
-  uint8_t data[20];	/*  0-3  CRC32 of the uncompressed data */
-			/*  4-11 size of the uncompressed data */
-			/* 12-19 member size including header and trailer */
+  uint8_t data[20];	//  0-3  CRC32 of the uncompressed data
+			//  4-11 size of the uncompressed data
+			// 12-19 member size including header and trailer
 
   enum { size = 20 };
 
@@ -291,7 +292,7 @@ int open_instream( const char * const name, struct stat * const in_statsp,
                    const bool no_ofile, const bool reg_only = false );
 bool file_exists( const std::string & filename );
 int open_outstream_rw( const std::string & output_filename, const bool force );
-void show_header( const unsigned dictionary_size );
+void show_header( const unsigned dictionary_size, const int vlevel = 3 );
 void show_error( const char * const msg, const int errcode = 0,
                  const bool help = false );
 void internal_error( const char * const msg );
@@ -328,6 +329,7 @@ int debug_show_packets( const std::string & input_filename,
                         const uint8_t bad_value );
 
 // defined in split.cc
+bool verify_header( const File_header & header, const Pretty_print & pp );
 int split_file( const std::string & input_filename,
                 const std::string & default_output_filename,
                 const int verbosity, const bool force );
diff --git a/main.cc b/main.cc
index 9425858..7845d90 100644
--- a/main.cc
+++ b/main.cc
@@ -24,6 +24,7 @@
 #define _FILE_OFFSET_BITS 64
 
 #include <algorithm>
+#include <cctype>
 #include <cerrno>
 #include <climits>
 #include <csignal>
@@ -104,6 +105,7 @@ void show_help()
   std::printf( "\nOptions:\n"
                "  -h, --help                      display this help and exit\n"
                "  -V, --version                   output version information and exit\n"
+               "  -a, --trailing-error            exit with error status if trailing data\n"
                "  -c, --stdout                    send decompressed output to standard output\n"
                "  -d, --decompress                decompress\n"
                "  -D, --range-decompress=<range>  decompress a range of bytes (N-M) to stdout\n"
@@ -146,9 +148,9 @@ void show_version()
 
 } // end namespace
 
-void show_header( const unsigned dictionary_size )
+void show_header( const unsigned dictionary_size, const int vlevel )
   {
-  if( verbosity >= 3 )
+  if( verbosity >= vlevel )
     {
     const char * const prefix[8] =
       { "Ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi", "Yi" };
@@ -309,7 +311,7 @@ int open_instream( const char * const name, struct stat * const in_statsp,
         std::fprintf( stderr, "%s: Input file '%s' is not a regular file%s.\n",
                       program_name, name,
                       ( can_read && !no_ofile ) ?
-                      " and '--stdout' was not specified" : "" );
+                      ",\n             and '--stdout' was not specified" : "" );
       close( infd );
       infd = -1;
       }
@@ -373,14 +375,14 @@ void cleanup_and_fail( const int retval )
   }
 
 
-     /* Set permissions, owner and times. */
+     // Set permissions, owner and times.
 void close_and_set_permissions( const struct stat * const in_statsp )
   {
   bool warning = false;
   if( in_statsp )
     {
     const mode_t mode = in_statsp->st_mode;
-    /* fchown will in many cases return with EPERM, which can be safely ignored. */
+    // fchown will in many cases return with EPERM, which can be safely ignored.
     if( fchown( outfd, in_statsp->st_uid, in_statsp->st_gid ) == 0 )
       { if( fchmod( outfd, mode ) != 0 ) warning = true; }
     else
@@ -424,36 +426,42 @@ unsigned char xdigit( const int value )
   }
 
 
-void show_trailing_garbage( const uint8_t * const data, const int size,
-                            const Pretty_print & pp, const bool all )
+bool show_trailing_data( const uint8_t * const data, const int size,
+                         const Pretty_print & pp, const bool all,
+                         const bool ignore_trailing )
   {
-  std::string garbage_msg;
-  if( !all ) garbage_msg = "first bytes of ";
-  garbage_msg += "trailing garbage found = ";
-  bool text = true;
-  for( int i = 0; i < size; ++i )
-    if( !std::isprint( data[i] ) ) { text = false; break; }
-  if( text )
-    {
-    garbage_msg += '\'';
-    garbage_msg.append( (const char *)data, size );
-    garbage_msg += '\'';
-    }
-  else
+  if( verbosity >= 4 || !ignore_trailing )
     {
+    std::string msg;
+    if( !all ) msg = "first bytes of ";
+    msg += "trailing data = ";
+    bool text = true;
     for( int i = 0; i < size; ++i )
+      if( !std::isprint( data[i] ) ) { text = false; break; }
+    if( text )
+      {
+      msg += '\'';
+      msg.append( (const char *)data, size );
+      msg += '\'';
+      }
+    else
       {
-      if( i > 0 ) garbage_msg += ' ';
-      garbage_msg += xdigit( data[i] >> 4 );
-      garbage_msg += xdigit( data[i] & 0x0F );
+      for( int i = 0; i < size; ++i )
+        {
+        if( i > 0 ) msg += ' ';
+        msg += xdigit( data[i] >> 4 );
+        msg += xdigit( data[i] & 0x0F );
+        }
       }
+    pp( msg.c_str() );
+    if( !ignore_trailing ) show_error( "Trailing data not allowed." );
     }
-  garbage_msg += '.';
-  pp( garbage_msg.c_str() );
+  return ignore_trailing;
   }
 
 
-int decompress( const int infd, const Pretty_print & pp, const bool testing )
+int decompress( const int infd, const Pretty_print & pp,
+                const bool ignore_trailing, const bool testing )
   {
   int retval = 0;
 
@@ -469,16 +477,17 @@ int decompress( const int infd, const Pretty_print & pp, const bool testing )
         {
         if( first_member )
           { pp( "File ends unexpectedly at member header." ); retval = 2; }
-        else if( verbosity >= 4 && size > 0 )
-          show_trailing_garbage( header.data, size, pp, true );
+        else if( size > 0 && !show_trailing_data( header.data, size, pp,
+                                                  true, ignore_trailing ) )
+          retval = 2;
         break;
         }
       if( !header.verify_magic() )
         {
         if( first_member )
           { pp( "Bad magic number (file not in lzip format)." ); retval = 2; }
-        else if( verbosity >= 4 )
-          show_trailing_garbage( header.data, size, pp, false );
+        else if( !show_trailing_data( header.data, size, pp, false, ignore_trailing ) )
+          retval = 2;
         break;
         }
       if( !header.verify_version() )
@@ -620,13 +629,15 @@ int main( const int argc, const char * const argv[] )
   Mode program_mode = m_none;
   uint8_t bad_value = 0;
   bool force = false;
-  bool ignore = false;
+  bool ignore_errors = false;
+  bool ignore_trailing = true;
   bool keep_input_files = false;
   bool to_stdout = false;
   invocation_name = argv[0];
 
   const Arg_parser::Option options[] =
     {
+    { 'a', "trailing-error",   Arg_parser::no  },
     { 'c', "stdout",           Arg_parser::no  },
     { 'd', "decompress",       Arg_parser::no  },
     { 'D', "range-decompress", Arg_parser::yes },
@@ -657,17 +668,18 @@ int main( const int argc, const char * const argv[] )
   for( ; argind < parser.arguments(); ++argind )
     {
     const int code = parser.code( argind );
-    if( !code ) break;					/* no more options */
+    if( !code ) break;					// no more options
     const std::string & arg = parser.argument( argind );
     switch( code )
       {
+      case 'a': ignore_trailing = false; break;
       case 'c': to_stdout = true; break;
       case 'd': set_mode( program_mode, m_decompress ); break;
       case 'D': set_mode( program_mode, m_range_dec );
                 parse_range( arg.c_str(), range ); break;
       case 'f': force = true; break;
       case 'h': show_help(); return 0;
-      case 'i': ignore = true; break;
+      case 'i': ignore_errors = true; break;
       case 'k': keep_input_files = true; break;
       case 'l': set_mode( program_mode, m_list ); break;
       case 'm': set_mode( program_mode, m_merge ); break;
@@ -688,7 +700,7 @@ int main( const int argc, const char * const argv[] )
                 parse_pos_value( arg.c_str(), bad_pos, bad_value ); break;
       default : internal_error( "uncaught option." );
       }
-    } /* end process options */
+    } // end process options
 
 #if defined(__MSVCRT__) || defined(__OS2__)
   setmode( STDIN_FILENO, O_BINARY );
@@ -731,8 +743,8 @@ int main( const int argc, const char * const argv[] )
       return merge_files( filenames, default_output_filename, verbosity, force );
     case m_range_dec:
       one_file( filenames.size() );
-      return range_decompress( filenames[0], default_output_filename,
-                               range, verbosity, force, ignore, to_stdout );
+      return range_decompress( filenames[0], default_output_filename, range,
+                               verbosity, force, ignore_errors, to_stdout );
     case m_repair:
       one_file( filenames.size() );
       if( default_output_filename.empty() )
@@ -823,7 +835,7 @@ int main( const int argc, const char * const argv[] )
       delete_output_on_interrupt = true;
     const struct stat * const in_statsp = input_filename.size() ? &in_stats : 0;
     pp.set_name( input_filename );
-    const int tmp = decompress( infd, pp, program_mode == m_test );
+    const int tmp = decompress( infd, pp, ignore_trailing, program_mode == m_test );
     if( tmp > retval ) retval = tmp;
     if( tmp && program_mode != m_test ) cleanup_and_fail( retval );
 
diff --git a/mtester.cc b/mtester.cc
index a9ac06e..92de2e0 100644
--- a/mtester.cc
+++ b/mtester.cc
@@ -56,7 +56,7 @@ void LZ_mtester::flush_data()
     {
     const int size = pos - stream_pos;
     crc32.update_buf( crc_, buffer + stream_pos, size );
-    if( pos >= buffer_size ) { partial_data_pos += pos; pos = 0; }
+    if( pos >= dictionary_size ) { partial_data_pos += pos; pos = 0; }
     stream_pos = pos;
     }
   }
@@ -89,11 +89,11 @@ void LZ_mtester::print_block( const int len )
 
 void LZ_mtester::duplicate_buffer()
   {
-  uint8_t * const tmp = new uint8_t[buffer_size];
+  uint8_t * const tmp = new uint8_t[dictionary_size];
   if( data_position() > 0 )
     std::memcpy( tmp, buffer, std::min( data_position(),
-                                        (unsigned long long)buffer_size ) );
-  else tmp[buffer_size-1] = 0;		// prev_byte of first byte
+                                        (unsigned long long)dictionary_size ) );
+  else tmp[dictionary_size-1] = 0;		// prev_byte of first byte
   buffer = tmp;
   }
 
@@ -232,7 +232,7 @@ int LZ_mtester::debug_decode_member( const long long dpos, const long long mpos,
                        format_byte( match_byte ) );
         }
       }
-    else					/* match or repeated match */
+    else					// match or repeated match
       {
       int len;
       if( rdec.decode_bit( bm_rep[state()] ) != 0 )		// 2nd bit
@@ -271,7 +271,7 @@ int LZ_mtester::debug_decode_member( const long long dpos, const long long mpos,
           std::printf( "%6llu %6llu  rep%c  %6u,%3d (%6llu)",
                        mp, dp, rep + '0', rep0 + 1, len, dp - rep0 - 1 );
         }
-      else					/* match */
+      else					// match
         {
         const unsigned rep0_saved = rep0;
         len = min_match_len + rdec.decode_len( match_len_model, pos_state );
diff --git a/mtester.h b/mtester.h
index 795d8e4..71df64d 100644
--- a/mtester.h
+++ b/mtester.h
@@ -194,14 +194,13 @@ class LZ_mtester
   unsigned long long partial_data_pos;
   Range_mtester rdec;
   const unsigned dictionary_size;
-  const int buffer_size;
-  uint8_t * buffer;		/* output buffer */
-  int pos;			/* current pos in buffer */
-  int stream_pos;		/* first byte not yet written to file */
+  uint8_t * buffer;		// output buffer
+  unsigned pos;			// current pos in buffer
+  unsigned stream_pos;		// first byte not yet written to file
   uint32_t crc_;
-  unsigned rep0;		/* rep[0-3] latest four distances */
-  unsigned rep1;		/* used for efficient coding of */
-  unsigned rep2;		/* repeated distances */
+  unsigned rep0;		// rep[0-3] latest four distances
+  unsigned rep1;		// used for efficient coding of
+  unsigned rep2;		// repeated distances
   unsigned rep3;
   State state;
 
@@ -225,37 +224,42 @@ class LZ_mtester
 
   uint8_t peek_prev() const
     {
-    const int i = ( ( pos > 0 ) ? pos : buffer_size ) - 1;
+    const unsigned i = ( ( pos > 0 ) ? pos : dictionary_size ) - 1;
     return buffer[i];
     }
 
-  uint8_t peek( const int distance ) const
+  uint8_t peek( const unsigned distance ) const
     {
-    int i = pos - distance - 1;
-    if( i < 0 ) i += buffer_size;
+    unsigned i = pos - distance - 1;
+    if( pos <= distance ) i += dictionary_size;
     return buffer[i];
     }
 
   void put_byte( const uint8_t b )
     {
     buffer[pos] = b;
-    if( ++pos >= buffer_size ) flush_data();
+    if( ++pos >= dictionary_size ) flush_data();
     }
 
-  void copy_block( const int distance, int len )
+  void copy_block( const unsigned distance, unsigned len )
     {
-    int i = pos - distance - 1;
-    if( i < 0 ) i += buffer_size;
-    if( len < buffer_size - std::max( pos, i ) && len <= std::abs( pos - i ) )
+    unsigned i = pos - distance - 1;
+    bool fast;
+    if( pos <= distance )
+      { i += dictionary_size;
+        fast = ( len <= dictionary_size - i && len <= i - pos ); }
+    else
+      fast = ( len < dictionary_size - pos && len <= pos - i );
+    if( fast )					// no wrap, no overlap
       {
-      std::memcpy( buffer + pos, buffer + i, len );	// no wrap, no overlap
+      std::memcpy( buffer + pos, buffer + i, len );
       pos += len;
       }
     else for( ; len > 0; --len )
       {
       buffer[pos] = buffer[i];
-      if( ++pos >= buffer_size ) flush_data();
-      if( ++i >= buffer_size ) i = 0;
+      if( ++pos >= dictionary_size ) flush_data();
+      if( ++i >= dictionary_size ) i = 0;
       }
     }
 
@@ -268,8 +272,7 @@ public:
     partial_data_pos( 0 ),
     rdec( ibuf, ibuf_size ),
     dictionary_size( dict_size ),
-    buffer_size( std::max( 65536U, dictionary_size ) ),
-    buffer( new uint8_t[buffer_size] ),
+    buffer( new uint8_t[dictionary_size] ),
     pos( 0 ),
     stream_pos( 0 ),
     crc_( 0xFFFFFFFFU ),
@@ -277,7 +280,7 @@ public:
     rep1( 0 ),
     rep2( 0 ),
     rep3( 0 )
-    { buffer[buffer_size-1] = 0; }	// prev_byte of first byte
+    { buffer[dictionary_size-1] = 0; }		// prev_byte of first byte
 
   ~LZ_mtester() { delete[] buffer; }
 
diff --git a/range_dec.cc b/range_dec.cc
index d4a2b2c..c6ccb7a 100644
--- a/range_dec.cc
+++ b/range_dec.cc
@@ -48,16 +48,7 @@ int decompress_member( const int infd, const int outfd,
     rdec.read_data( header.data, File_header::size );
     if( rdec.finished() )			// End Of File
       { pp( "File ends unexpectedly at member header." ); return 2; }
-    if( !header.verify_magic() )
-      { pp( "Bad magic number (file not in lzip format)." ); return 2; }
-    if( !header.verify_version() )
-      {
-      if( pp.verbosity() >= 0 )
-        { pp();
-          std::fprintf( stderr, "Version %d member format not supported.\n",
-                        header.version() ); }
-      return 2;
-      }
+    if( !verify_header( header, pp ) ) return 2;
     const unsigned dictionary_size = header.dictionary_size();
     if( dictionary_size < min_dictionary_size ||
         dictionary_size > max_dictionary_size )
@@ -101,7 +92,12 @@ int list_file( const char * const input_filename, const Pretty_print & pp )
     {
     const unsigned long long data_size = file_index.data_end();
     const unsigned long long file_size = file_index.file_end();
+    unsigned dictionary_size = 0;
+    for( long i = 0; i < file_index.members(); ++i )
+      if( dictionary_size < file_index.dictionary_size( i ) )
+        dictionary_size = file_index.dictionary_size( i );
     pp( 0, stdout );
+    show_header( dictionary_size, 1 );
     if( data_size > 0 && file_size > 0 )
       std::printf( "%6.3f:1, %6.3f bits/byte, %5.2f%% saved.  ",
                    (double)data_size / file_size,
@@ -123,6 +119,10 @@ int list_file( const char * const input_filename, const Pretty_print & pp )
                        db.pos(), db.size(), mb.pos(), mb.size() );
           }
       }
+    const long long trailing_size = file_index.file_size() - file_index.file_end();
+    if( pp.verbosity() >= 1 && trailing_size > 0 )
+      std::printf( "    %lld bytes of trailing data at end of file.\n",
+                   trailing_size );
     }
   return 0;
   }
diff --git a/repair.cc b/repair.cc
index e83b843..e8588e3 100644
--- a/repair.cc
+++ b/repair.cc
@@ -41,10 +41,9 @@ bool gross_damage( const long long msize, const uint8_t * const mbuffer )
   enum { maxlen = 6 };		// max number of consecutive identical bytes
   long i = File_header::size;
   const long end = msize - File_trailer::size - maxlen;
-  uint8_t byte;
   while( i < end )
     {
-    byte = mbuffer[i];
+    const uint8_t byte = mbuffer[i];
     int len = 0;			// does not count the first byte
     while( mbuffer[++i] == byte && ++len < maxlen ) {}
     if( len >= maxlen ) return true;
diff --git a/split.cc b/split.cc
index 2ffb359..fc92ea4 100644
--- a/split.cc
+++ b/split.cc
@@ -62,25 +62,6 @@ bool next_filename( std::string & output_filename, const int max_digits )
   }
 
 
-bool verify_header( const File_header & header, const Pretty_print & pp )
-  {
-  if( !header.verify_magic() )
-    {
-    pp( "Bad magic number (file not in lzip format)." );
-    return false;
-    }
-  if( !header.verify_version() )
-    {
-    if( pp.verbosity() >= 0 )
-      { pp();
-        std::fprintf( stderr, "Version %d member format not supported.\n",
-                      header.version() ); }
-    return false;
-    }
-  return true;
-  }
-
-
 // Search forward from 'pos' for "LZIP" (Boyer-Moore algorithm)
 // Returns pos of found string or 'pos+size' if not found.
 //
@@ -205,6 +186,25 @@ int do_split_file( const std::string & input_filename, uint8_t * & base_buffer,
 } // end namespace
 
 
+bool verify_header( const File_header & header, const Pretty_print & pp )
+  {
+  if( !header.verify_magic() )
+    {
+    pp( "Bad magic number (file not in lzip format)." );
+    return false;
+    }
+  if( !header.verify_version() )
+    {
+    if( pp.verbosity() >= 0 )
+      { pp();
+        std::fprintf( stderr, "Version %d member format not supported.\n",
+                      header.version() ); }
+    return false;
+    }
+  return true;
+  }
+
+
 int split_file( const std::string & input_filename,
                 const std::string & default_output_filename,
                 const int verbosity, const bool force )
diff --git a/testsuite/check.sh b/testsuite/check.sh
index 8a9c81d..537f5f0 100755
--- a/testsuite/check.sh
+++ b/testsuite/check.sh
@@ -57,13 +57,10 @@ fail=0
 
 printf "testing lziprecover-%s..." "$2"
 
-printf "  in: Bad magic number (file not in lzip format).\n" > msg
-"${LZIP}" -t in 2> out
-if [ $? = 2 ] && cmp out msg ; then printf . ; else printf - ; fail=1 ; fi
-printf "  (stdin): Bad magic number (file not in lzip format).\n" > msg
-"${LZIP}" -t < in 2> out
-if [ $? = 2 ] && cmp out msg ; then printf . ; else printf - ; fail=1 ; fi
-rm -f out msg
+"${LZIP}" -tq in
+if [ $? = 2 ] ; then printf . ; else printf - ; fail=1 ; fi
+"${LZIP}" -tq < in
+if [ $? = 2 ] ; then printf . ; else printf - ; fail=1 ; fi
 "${LZIP}" -cdq in
 if [ $? = 2 ] ; then printf . ; else printf - ; fail=1 ; fi
 "${LZIP}" -cdq < in
@@ -110,6 +107,15 @@ cmp in2 copy2 || fail=1
 printf .
 
 printf "garbage" >> copy2.lz || framework_failure
+rm -f copy2
+"${LZIP}" -atq copy2.lz
+if [ $? = 2 ] ; then printf . ; else printf - ; fail=1 ; fi
+"${LZIP}" -atq < copy2.lz
+if [ $? = 2 ] ; then printf . ; else printf - ; fail=1 ; fi
+"${LZIP}" -adkq copy2.lz
+if [ $? = 2 ] && [ ! -e copy2 ] ; then printf . ; else printf - ; fail=1 ; fi
+"${LZIP}" -adkq -o copy2 < copy2.lz
+if [ $? = 2 ] && [ ! -e copy2 ] ; then printf . ; else printf - ; fail=1 ; fi
 printf "to be overwritten" > copy2 || framework_failure
 "${LZIP}" -df copy2.lz || fail=1
 cmp in2 copy2 || fail=1
@@ -125,6 +131,8 @@ if [ $? = 2 ] && cmp "${f5b1}" copy ; then printf . ; else printf - ; fail=1 ; f
 "${LZIPRECOVER}" -D0 -iq "${f5b1_lz}" > copy
 if [ $? = 2 ] && cmp "${f5b1}" copy ; then printf . ; else printf - ; fail=1 ; fi
 
+printf "\ntesting --merge  ..."
+
 rm -f copy.lz
 "${LZIPRECOVER}" -m -o copy.lz "${fox5_lz}" "${f5b1_lz}"
 if [ $? = 0 ] && [ ! -e copy.lz ] ; then printf . ; else printf - ; fail=1 ; fi
@@ -144,8 +152,8 @@ for i in "${f5b1_lz}" "${f5b3_lz}" "${f5b4_lz}" "${f5b5_lz}" ; do
 	cmp "${fox5_lz}" copy.lz || fail=1
 	"${LZIPRECOVER}" -mf -o copy.lz "${i}" "${f5b2_lz}" || fail=1
 	cmp "${fox5_lz}" copy.lz || fail=1
+	printf .
 done
-printf .
 
 for i in "${f5b3_lz}" "${f5b4_lz}" "${f5b5_lz}" ; do
 	"${LZIPRECOVER}" -mf -o copy.lz "${f5b1_lz}" "${f5b2_lz}" "${i}" || fail=1
@@ -160,21 +168,25 @@ for i in "${f5b3_lz}" "${f5b4_lz}" "${f5b5_lz}" ; do
 	cmp "${fox5_lz}" copy.lz || fail=1
 	"${LZIPRECOVER}" -mf -o copy.lz "${i}" "${f5b2_lz}" "${f5b1_lz}" || fail=1
 	cmp "${fox5_lz}" copy.lz || fail=1
+	printf .
 done
-printf .
 
 "${LZIPRECOVER}" -mf -o copy.lz "${f5b3_lz}" "${f5b4_lz}" "${f5b5_lz}" || fail=1
 cmp "${fox5_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${f5b1_lz}" "${f5b3_lz}" "${f5b4_lz}" "${f5b5_lz}" || fail=1
 cmp "${fox5_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${f5b2_lz}" "${f5b3_lz}" "${f5b4_lz}" "${f5b5_lz}" || fail=1
 cmp "${fox5_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${f5b1_lz}" "${f5b2_lz}" "${f5b3_lz}" "${f5b4_lz}" "${f5b5_lz}" || fail=1
 cmp "${fox5_lz}" copy.lz || fail=1
 printf .
 
 "${LZIPRECOVER}" -mf -o copy.lz "${bad1_lz}" "${bad2_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${bad2_lz}" "${bad1_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
 printf .
@@ -185,14 +197,19 @@ cat "${bad2_lz}" "${in_lz}" "${bad2_lz}" "${bad2_lz}" > bad22.lz || framework_fa
 cat "${in_lz}" "${in_lz}" "${in_lz}" "${in_lz}" > copy4.lz || framework_failure
 "${LZIPRECOVER}" -mf -o out4.lz bad11.lz bad12.lz bad22.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad11.lz bad22.lz bad12.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad12.lz bad11.lz bad22.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad12.lz bad22.lz bad11.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad22.lz bad11.lz bad12.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad22.lz bad12.lz bad11.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
 printf .
@@ -204,19 +221,24 @@ for i in "${bad1_lz}" "${bad2_lz}" ; do
 		"${LZIPRECOVER}" -mf -o copy.lz "${j}" "${i}" || fail=1
 		cmp "${in_lz}" copy.lz || fail=1
 	done
+	printf .
 done
-printf .
 
 "${LZIPRECOVER}" -mf -o copy.lz "${bad3_lz}" "${bad4_lz}" "${bad5_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${bad3_lz}" "${bad5_lz}" "${bad4_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${bad4_lz}" "${bad3_lz}" "${bad5_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${bad4_lz}" "${bad5_lz}" "${bad3_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${bad5_lz}" "${bad3_lz}" "${bad4_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o copy.lz "${bad5_lz}" "${bad4_lz}" "${bad3_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
 printf .
@@ -227,18 +249,25 @@ cat "${bad5_lz}" "${bad3_lz}" "${bad4_lz}" "${in_lz}" > bad534.lz || framework_f
 cat "${in_lz}" "${in_lz}" "${in_lz}" "${in_lz}" > copy4.lz || framework_failure
 "${LZIPRECOVER}" -mf -o out4.lz bad345.lz bad453.lz bad534.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad345.lz bad534.lz bad453.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad453.lz bad345.lz bad534.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad453.lz bad534.lz bad345.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad534.lz bad345.lz bad453.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
+printf .
 "${LZIPRECOVER}" -mf -o out4.lz bad534.lz bad453.lz bad345.lz || fail=1
 cmp out4.lz copy4.lz || fail=1
 printf .
 
+printf "\ntesting --repair ..."
+
 rm -f copy.lz
 "${LZIPRECOVER}" -R -o copy.lz "${fox5_lz}" || fail=1
 if [ $? = 0 ] && [ ! -e copy.lz ] ; then printf . ; else printf - ; fail=1 ; fi
@@ -250,6 +279,7 @@ if [ $? = 2 ] && [ ! -e copy.lz ] ; then printf . ; else printf - ; fail=1 ; fi
 if [ $? = 2 ] && [ ! -e copy.lz ] ; then printf . ; else printf - ; fail=1 ; fi
 "${LZIPRECOVER}" -Rf -o copy.lz "${f5b1_lz}" || fail=1
 cmp "${fox5_lz}" copy.lz || fail=1
+printf .
 "${LZIPRECOVER}" -Rf -o copy.lz "${bad1_lz}" || fail=1
 cmp "${in_lz}" copy.lz || fail=1
 printf .
@@ -264,14 +294,17 @@ mv copy.lz copy.tlz || framework_failure
 "${LZIPRECOVER}" -R copy.tlz || fail=1
 if [ $? = 0 ] && [ -e copy_fixed.tlz ] ; then printf . ; else printf - ; fail=1 ; fi
 
+printf "\ntesting --split  ..."
+
 cat "${in_lz}" "${in_lz}" "${in_lz}" > copy || framework_failure
 printf "garbage" >> copy || fail=1
 "${LZIPRECOVER}" -s -o copy.lz copy || fail=1
+printf .
 for i in 1 2 3 ; do
 	"${LZIPRECOVER}" -cd rec${i}copy.lz > copy || fail=1
 	cmp in copy || fail=1
+	printf .
 done
-printf .
 
 echo
 if [ ${fail} = 0 ] ; then