use strict;
use warnings;
use bytes;

use Test::More ;

use IO::Handle qw(SEEK_SET SEEK_CUR SEEK_END);
use CompTestUtils;

our ($UncompressClass);
BEGIN 
{ 
    # use Test::NoWarnings, if available
    my $extra = 0 ;

    my $st = eval { require Test::NoWarnings ;  import Test::NoWarnings; 1; };
    $extra = 1
        if $st ;

    plan(tests => 799 + $extra) ;
}

sub myGZreadFile
{
    my $filename = shift ;
    my $init = shift ;


    my $fil = new $UncompressClass $filename,
                                    -Strict   => 0,
                                    -Append   => 1
                                    ;

    my $data = '';
    $data = $init if defined $init ;
    1 while $fil->read($data) > 0;

    $fil->close ;
    return $data ;
}

sub run
{
    my $CompressClass   = identify();
    $UncompressClass    = getInverse($CompressClass);
    my $Error           = getErrorRef($CompressClass);
    my $UnError         = getErrorRef($UncompressClass);

    if(1)
    {

        title "Testing $CompressClass Errors";

        # Buffer not writable
        eval qq[\$a = new $CompressClass(\\1) ;] ;
        like $@, mkEvalErr("^$CompressClass: output buffer is read-only") ;
            
        my($out, $gz);
            
        my $x ;
        $gz = new $CompressClass(\$x); 

        foreach my $name (qw(read readline getc))
        {
            eval " \$gz->$name() " ;
            like $@, mkEvalErr("^$name Not Available: File opened only for output");
        }

        eval ' $gz->write({})' ;
        like $@, mkEvalErr("^${CompressClass}::write: not a scalar reference");

        eval ' $gz->syswrite("abc", 1, 5)' ;
        like $@, mkEvalErr("^${CompressClass}::write: offset outside string");

        eval ' $gz->syswrite("abc", 1, -4)' ;
        like $@, mkEvalErr("^${CompressClass}::write: offset outside string"), "write outside string";
    }


    {
        title "Testing $UncompressClass Errors";

        my $out = "" ;

        my $lex = new LexFile my $name ;

        ok ! -e $name, "  $name does not exist";
        
        $a = new $UncompressClass "$name" ;
        is $a, undef;

        my $gc ;
        my $guz = new $CompressClass(\$gc); 
        $guz->write("abc") ;
        $guz->close();

        my $x ;
        my $gz = new $UncompressClass(\$gc); 

        foreach my $name (qw(print printf write))
        {
            eval " \$gz->$name() " ;
            like $@, mkEvalErr("^$name Not Available: File opened only for intput");
        }

    }


    {
        title "Testing $CompressClass and $UncompressClass";

        {
            my ($a, $x, @x) = ("","","") ;

            # Buffer not a scalar reference
            eval qq[\$a = new $CompressClass \\\@x ;] ;
            like $@, mkEvalErr("^$CompressClass: output parameter not a filename, filehandle or scalar ref");
                
            # Buffer not a scalar reference
            eval qq[\$a = new $UncompressClass \\\@x ;] ;
            like $@, mkEvalErr("^$UncompressClass: input parameter not a filename, filehandle, array ref or scalar ref");
        }
            
        foreach my $Type ( $CompressClass, $UncompressClass)
        {
            # Check error handling with IO::Compress::Deflate and IO::Uncompress::Inflate

            my ($a, $x, @x) = ("","","") ;

            # Odd number of parameters
            eval qq[\$a = new $Type "abc", -Output ] ;
            like $@, mkEvalErr("^$Type: Expected even number of parameters, got 1");

            # Unknown parameter
            eval qq[\$a = new $Type  "anc", -Fred => 123 ;] ;
            like $@, mkEvalErr("^$Type: unknown key value\\(s\\) Fred");

            # no in or out param
            eval qq[\$a = new $Type ;] ;
            like $@, mkEvalErr("^$Type: Missing (Input|Output) parameter");

        }    


        {
            # write a very simple compressed file 
            # and read back 
            #========================================


            my $lex = new LexFile my $name ;

            my $hello = <<EOM ;
hello world
this is a test
EOM

            {
              my $x ;
              ok $x = new $CompressClass $name  ;
              is $x->autoflush(1), 0, "autoflush";
              is $x->autoflush(1), 1, "autoflush";
              ok $x->opened(), "opened";

              ok $x->write($hello), "write" ;
              ok $x->flush(), "flush";
              ok $x->close, "close" ;
              ok ! $x->opened(), "! opened";
            }

            {
              my $uncomp;
              ok my $x = new $UncompressClass $name, -Append => 1  ;
              ok $x->opened(), "opened";

              my $len ;
              1 while ($len = $x->read($uncomp)) > 0 ;

              is $len, 0, "read returned 0"
                or diag $$UnError ;

              ok $x->close ;
              is $uncomp, $hello ;
              ok !$x->opened(), "! opened";
            }
        }

        {
            # write a very simple compressed file 
            # and read back 
            #========================================


            my $lex = new LexFile my $name ;

            my $hello = <<EOM ;
hello world
this is a test
EOM

            {
              my $x ;
              ok $x = new $CompressClass $name  ;

              is $x->write(''), 0, "Write empty string is ok";
              is $x->write(undef), 0, "Write undef is ok";
              ok $x->write($hello), "Write ok" ;
              ok $x->close, "Close ok" ;
            }

            {
              my $uncomp;
              my $x = new $UncompressClass $name  ;
              ok $x, "creates $UncompressClass $name"  ;

              my $data = '';
              $data .= $uncomp while $x->read($uncomp) > 0 ;

              ok $x->close, "close ok" ;
              is $data, $hello, "expected output" ;
            }
        }


        {
            # write a very simple file with using an IO filehandle
            # and read back 
            #========================================


            my $lex = new LexFile my $name ;

            my $hello = <<EOM ;
hello world
this is a test
EOM

            {
              my $fh = new IO::File ">$name" ;
              ok $fh, "opened file $name ok";
              my $x = new $CompressClass $fh  ;
              ok $x, " created $CompressClass $fh"  ;

              is $x->fileno(), fileno($fh), "fileno match" ;
              is $x->write(''), 0, "Write empty string is ok";
              is $x->write(undef), 0, "Write undef is ok";
              ok $x->write($hello), "write ok" ;
              ok $x->flush(), "flush";
              ok $x->close,"close" ;
              $fh->close() ;
            }

            my $uncomp;
            {
              my $x ;
              ok my $fh1 = new IO::File "<$name" ;
              ok $x = new $UncompressClass $fh1, -Append => 1  ;
              ok $x->fileno() == fileno $fh1 ;

              1 while $x->read($uncomp) > 0 ;

              ok $x->close ;
            }

            ok $hello eq $uncomp ;
        }

        {
            # write a very simple file with using a glob filehandle
            # and read back 
            #========================================


            my $lex = new LexFile my $name ;
            #my $name  = "/tmp/fred";

            my $hello = <<EOM ;
hello world
this is a test
EOM

            {
              title "$CompressClass: Input from typeglob filehandle";  
              ok open FH, ">$name" ;
     
              my $x = new $CompressClass *FH  ;
              ok $x, "  create $CompressClass"  ;

              is $x->fileno(), fileno(*FH), "  fileno" ;
              is $x->write(''), 0, "  Write empty string is ok";
              is $x->write(undef), 0, "  Write undef is ok";
              ok $x->write($hello), "  Write ok" ;
              ok $x->flush(), "  Flush";
              ok $x->close, "  Close" ;
              close FH;
            }


            my $uncomp;
            {
              title "$UncompressClass: Input from typeglob filehandle, append output";  
              my $x ;
              ok open FH, "<$name" ;
              ok $x = new $UncompressClass *FH, -Append => 1, Transparent => 0
                or diag $$UnError ;
              is $x->fileno(), fileno FH, "  fileno ok" ;

              1 while $x->read($uncomp) > 0 ;

              ok $x->close, "  close" ;
              close FH;
            }

            is $uncomp, $hello, "  expected output" ;
        }

        {
            my $lex = new LexFile my $name ;
            #my $name = "/tmp/fred";

            my $hello = <<EOM ;
hello world
this is a test
EOM

            {
              title "Outout to stdout via '-'" ;

              open(SAVEOUT, ">&STDOUT");
              my $dummy = fileno SAVEOUT;
              open STDOUT, ">$name" ;
     
              my $x = new $CompressClass '-'  ;
              $x->write($hello);
              $x->close;

              open(STDOUT, ">&SAVEOUT");

              ok 1, "  wrote to stdout" ;
            }
            is myGZreadFile($name), $hello, "  wrote OK";
            #hexDump($name);

            {
              title "Input from stdin via filename '-'";  

              my $x ;
              my $uncomp ;
              my $stdinFileno = fileno(STDIN);
              # open below doesn't return 1 sometimes on XP
                 open(SAVEIN, "<&STDIN");
              ok open(STDIN, "<$name"), "  redirect STDIN";
              my $dummy = fileno SAVEIN;
              $x = new $UncompressClass '-', Append => 1, Transparent => 0
                    or diag $$UnError ;
              ok $x, "  created object" ;
              is $x->fileno(), $stdinFileno, "  fileno ok" ;

              1 while $x->read($uncomp) > 0 ;

              ok $x->close, "  close" ;
                 open(STDIN, "<&SAVEIN");
              is $uncomp, $hello, "  expected output" ;
            }
        }

        {
            # write a compressed file to memory 
            # and read back 
            #========================================

            #my $name = "test.gz" ;
            my $lex = new LexFile my $name ;

            my $hello = <<EOM ;
hello world
this is a test
EOM

            my $buffer ;
            {
              my $x ;
              ok $x = new $CompressClass(\$buffer) ;
          
              ok ! defined $x->autoflush(1) ;
              ok ! defined $x->autoflush(1) ;
              ok ! defined $x->fileno() ;
              is $x->write(''), 0, "Write empty string is ok";
              is $x->write(undef), 0, "Write undef is ok";
              ok $x->write($hello) ;
              ok $x->flush();
              ok $x->close ;
          
              writeFile($name, $buffer) ;
              #is anyUncompress(\$buffer), $hello, "  any ok";
            }

            my $keep = $buffer ;
            my $uncomp;
            {
              my $x ;
              ok $x = new $UncompressClass(\$buffer, Append => 1)  ;

              ok ! defined $x->autoflush(1) ;
              ok ! defined $x->autoflush(1) ;
              ok ! defined $x->fileno() ;
              1 while $x->read($uncomp) > 0  ;

              ok $x->close, "closed" ;
            }

            is $uncomp, $hello, "got expected uncompressed data" ;
            ok $buffer eq $keep, "compressed input not changed" ;
        }

        if ($CompressClass ne 'RawDeflate')
        {
            # write empty file
            #========================================

            my $buffer = '';
            {
              my $x ;
              $x = new $CompressClass(\$buffer);
              ok $x, "new $CompressClass" ;
              ok $x->close, "close ok" ;
          
            }

            my $keep = $buffer ;
            my $uncomp= '';
            {
              my $x ;
              ok $x = new $UncompressClass(\$buffer, Append => 1)  ;

              1 while $x->read($uncomp) > 0  ;

              ok $x->close ;
            }

            ok $uncomp eq '' ;
            ok $buffer eq $keep ;

        }

        {
            # write a larger file
            #========================================


            my $lex = new LexFile my $name ;

            my $hello = <<EOM ;
hello world
this is a test
EOM

            my $input    = '' ;
            my $contents = '' ;

            {
              my $x = new $CompressClass $name  ;
              ok $x, "  created $CompressClass object";

              ok $x->write($hello), "  write ok" ;
              $input .= $hello ;
              ok $x->write("another line"), "  write ok" ;
              $input .= "another line" ;
              # all characters
              foreach (0 .. 255)
                { $contents .= chr int $_ }
              # generate a long random string
              foreach (1 .. 5000)
                { $contents .= chr int rand 256 }

              ok $x->write($contents), "  write ok" ;
              $input .= $contents ;
              ok $x->close, "  close ok" ;
            }

            ok myGZreadFile($name) eq $input ;
            my $x =  readFile($name) ;
            #print "length " . length($x) . " \n";
        }

        SKIP:
        {
            # embed a compressed file in another file
            #================================

            skip "zstd doesn't support trailing data", 11
                if $CompressClass =~ /zstd/i ;

            my $lex = new LexFile my $name ;

            my $hello = <<EOM ;
hello world
this is a test
EOM

            my $header = "header info\n" ;
            my $trailer = "trailer data\n" ;

            {
              my $fh ;
              ok $fh = new IO::File ">$name" ;
              print $fh $header ;
              my $x ;
              ok $x = new $CompressClass $fh,
                                         -AutoClose => 0   ;

              ok $x->binmode();
              ok $x->write($hello) ;
              ok $x->close ;
              print $fh $trailer ;
              $fh->close() ;
            }

            my ($fil, $uncomp) ;
            my $fh1 ;
            ok $fh1 = new IO::File "<$name" ;
            # skip leading junk
            my $line = <$fh1> ;
            ok $line eq $header ;

            ok my $x = new $UncompressClass $fh1, Append => 1  ;
            ok $x->binmode();
            1 while $x->read($uncomp) > 0 ;

            is $uncomp, $hello ;
            my $rest ;
            read($fh1, $rest, 5000);
            is $x->trailingData() . $rest, $trailer ;
            #print "# [".$x->trailingData() . "][$rest]\n" ;

        }

        SKIP:
        {
            # embed a compressed file in another buffer
            #================================

            skip "zstd doesn't support trailing data", 6
                if $CompressClass =~ /zstd/i ;

            my $hello = <<EOM ;
hello world
this is a test
EOM

            my $trailer = "trailer data" ;

            my $compressed ;

            {
              ok my $x = new $CompressClass(\$compressed);

              ok $x->write($hello) ;
              ok $x->close ;
              $compressed .= $trailer ;
            }

            my $uncomp;
            ok my $x = new $UncompressClass(\$compressed, Append => 1)  ;
            1 while $x->read($uncomp) > 0 ;

            ok $uncomp eq $hello ;
            is $x->trailingData(), $trailer ;

        }

        {
            # Write
            # these tests come almost 100% from IO::String

            my $lex = new LexFile my $name ;

            my $io = $CompressClass->new($name);

            is $io->tell(), 0, " tell returns 0"; ;

            my $heisan = "Heisan\n";
            $io->print($heisan) ;

            ok ! $io->eof(), "  ! eof";

            is $io->tell(), length($heisan), "  tell is " . length($heisan) ;

            $io->print("a", "b", "c");

            {
                local($\) = "\n";
                $io->print("d", "e");
                local($,) = ",";
                $io->print("f", "g", "h");
            }

            {
                local($\) ;
                $io->print("D", "E");
                local($,) = ".";
                $io->print("F", "G", "H");
            }

            my $foo = "1234567890";
            
            is $io->syswrite($foo, length($foo)), length($foo), "  syswrite ok" ;
            if ( $] < 5.6 )
              { is $io->syswrite($foo, length $foo), length $foo, "  syswrite ok" }
            else
              { is $io->syswrite($foo), length $foo, "  syswrite ok" }
            is $io->syswrite($foo, length($foo)), length $foo, "  syswrite ok";
            is $io->write($foo, length($foo), 5), 5,   " write 5";
            is $io->write("xxx\n", 100, -1), 1, "  write 1";

            for (1..3) {
                $io->printf("i(%d)", $_);
                $io->printf("[%d]\n", $_);
            }
            $io->print("\n");

            $io->close ;

            ok $io->eof(), "  eof";

            is myGZreadFile($name), "Heisan\nabcde\nf,g,h\nDEF.G.H" .
                                    ("1234567890" x 3) . "67890\n" .
                                        "i(1)[1]\ni(2)[2]\ni(3)[3]\n\n",
                                        "myGZreadFile ok";


        }

        {
            # Read
            my $str = <<EOT;
This is an example
of a paragraph


and a single line.

EOT

            my $lex = new LexFile my $name ;

            my %opts = () ;
            my $iow = new $CompressClass $name, %opts;
            is $iow->input_line_number, undef; 
            $iow->print($str) ;
            is $iow->input_line_number, undef; 
            $iow->close ;

            my @tmp;
            my $buf;
            {
                my $io = new $UncompressClass $name ;
            
                is $., 0; 
                is $io->input_line_number, 0; 
                ok ! $io->eof, "eof";
                is $io->tell(), 0, "tell 0" ;
                #my @lines = <$io>;
                my @lines = $io->getlines();
                is @lines, 6
                    or print "# Got " . scalar(@lines) . " lines, expected 6\n" ;
                is $lines[1], "of a paragraph\n" ;
                is join('', @lines), $str ;
                is $., 6; 
                is $io->input_line_number, 6; 
                is $io->tell(), length($str) ;
            
                ok $io->eof;

                ok ! ( defined($io->getline)  ||
                          (@tmp = $io->getlines) ||
                          defined($io->getline)         ||
                          defined($io->getc)     ||
                          $io->read($buf, 100)   != 0) ;
            }
            
            
            {
                local $/;  # slurp mode
                my $io = $UncompressClass->new($name);
                is $., 0, "line 0"; 
                is $io->input_line_number, 0; 
                ok ! $io->eof, "eof";
                my @lines = $io->getlines;
                is $., 1, "line 1"; 
                is $io->input_line_number, 1, "line number 1"; 
                ok $io->eof, "eof" ;
                ok @lines == 1 && $lines[0] eq $str;
            
                $io = $UncompressClass->new($name);
                ok ! $io->eof;
                my $line = $io->getline();
                ok $line eq $str;
                ok $io->eof;
            }
            
            {
                local $/ = "";  # paragraph mode
                my $io = $UncompressClass->new($name);
                is $., 0; 
                is $io->input_line_number, 0; 
                ok ! $io->eof;
                my @lines = $io->getlines();
                is $., 2; 
                is $io->input_line_number, 2; 
                ok $io->eof;
                ok @lines == 2 
                    or print "# Got " . scalar(@lines) . " lines, expected 2\n" ;
                ok $lines[0] eq "This is an example\nof a paragraph\n\n\n"
                    or print "# $lines[0]\n";
                ok $lines[1] eq "and a single line.\n\n";
            }
            
            {
                # Record mode
                my $reclen = 7 ;
                my $expected_records = int(length($str) / $reclen)
                                        + (length($str) % $reclen ? 1 : 0);
                local $/ = \$reclen;

                my $io = $UncompressClass->new($name);
                is $., 0; 
                is $io->input_line_number, 0; 

                ok ! $io->eof;
                my @lines = $io->getlines();
                is $., $expected_records; 
                is $io->input_line_number, $expected_records; 
                ok $io->eof;
                is @lines, $expected_records, 
                    "Got $expected_records records\n" ;
                ok $lines[0] eq substr($str, 0, $reclen)
                    or print "# $lines[0]\n";
                ok $lines[1] eq substr($str, $reclen, $reclen);
            }

            {
                local $/ = "is";
                my $io = $UncompressClass->new($name);
                my @lines = ();
                my $no = 0;
                my $err = 0;
                ok ! $io->eof;
                while (my $a = $io->getline()) {
                    push(@lines, $a);
                    $err++ if $. != ++$no;
                }
            
                ok $err == 0 ;
                ok $io->eof;
            
                is $., 3; 
                is $io->input_line_number, 3; 
                ok @lines == 3 
                    or print "# Got " . scalar(@lines) . " lines, expected 3\n" ;
                ok join("-", @lines) eq
                                 "This- is- an example\n" .
                                "of a paragraph\n\n\n" .
                                "and a single line.\n\n";
            }
            
            
            # Test read
            
            {
                my $io = $UncompressClass->new($name);
            

                eval { $io->read(1) } ;
                like $@, mkErr("buffer parameter is read-only");

                $buf = "abcd";
                is $io->read($buf, 0), 0, "Requested 0 bytes" ;
                is $buf, "", "Buffer empty";

                is $io->read($buf, 3), 3 ;
                is $buf, "Thi";
            
                is $io->sysread($buf, 3, 2), 3 ;
                is $buf, "Ths i"
                    or print "# [$buf]\n" ;;
                ok ! $io->eof;
            
                $buf = "ab" ;
                is $io->read($buf, 3, 4), 3 ;
                is $buf, "ab" . "\x00" x 2 . "s a"
                    or print "# [$buf]\n" ;;
                ok ! $io->eof;
            
                # read the rest of the file
                $buf = '';
                my $remain = length($str) - 9;
                is $io->read($buf, $remain+1), $remain ;
                is $buf, substr($str, 9);
                ok $io->eof;

                $buf = "hello";
                is $io->read($buf, 10), 0 ;
                is $buf, "", "Buffer empty";
                ok $io->eof;

                ok $io->close();
                $buf = "hello";
                is $io->read($buf, 10), 0 ;
                is $buf, "hello", "Buffer not empty";
                ok $io->eof;

        #        $io->seek(-4, 2);
        #    
        #        ok ! $io->eof;
        #    
        #        ok read($io, $buf, 20) == 4 ;
        #        ok $buf eq "e.\n\n";
        #    
        #        ok read($io, $buf, 20) == 0 ;
        #        ok $buf eq "";
        #   
        #        ok ! $io->eof;
            }

        }

        {
            # Read from non-compressed file

            my $str = <<EOT;
This is an example
of a paragraph


and a single line.

EOT
            my $lex = new LexFile my $name ;

            writeFile($name, $str);
            my @tmp;
            my $buf;
            {
                my $io = new $UncompressClass $name, -Transparent => 1 ;
            
                isa_ok $io, $UncompressClass ;
                ok ! $io->eof, "eof";
                is $io->tell(), 0, "tell == 0" ;
                my @lines = $io->getlines();
                is @lines, 6, "got 6 lines"; 
                ok $lines[1] eq "of a paragraph\n" ;
                ok join('', @lines) eq $str ;
                is $., 6; 
                is $io->input_line_number, 6; 
                ok $io->tell() == length($str) ;
            
                ok $io->eof;

                ok ! ( defined($io->getline)  ||
                          (@tmp = $io->getlines) ||
                          defined($io->getline)         ||
                          defined($io->getc)     ||
                          $io->read($buf, 100)   != 0) ;
            }
            
            
            {
                local $/;  # slurp mode
                my $io = $UncompressClass->new($name);
                ok ! $io->eof;
                my @lines = $io->getlines;
                is $., 1; 
                is $io->input_line_number, 1; 
                ok $io->eof;
                ok @lines == 1 && $lines[0] eq $str;
            
                $io = $UncompressClass->new($name);
                ok ! $io->eof;
                my $line = $io->getline;
                is $., 1; 
                is $io->input_line_number, 1; 
                is $line, $str;
                ok $io->eof;
            }
            
            {
                local $/ = "";  # paragraph mode
                my $io = $UncompressClass->new($name);
                ok ! $io->eof;
                my @lines = $io->getlines;
                is $., 2; 
                is $io->input_line_number, 2; 
                ok $io->eof;
                ok @lines == 2 
                    or print "# expected 2 lines, got " . scalar(@lines) . "\n";
                ok $lines[0] eq "This is an example\nof a paragraph\n\n\n"
                    or print "# [$lines[0]]\n" ;
                ok $lines[1] eq "and a single line.\n\n";
            }
            
            {
                # Record mode
                my $reclen = 7 ;
                my $expected_records = int(length($str) / $reclen)
                                        + (length($str) % $reclen ? 1 : 0);
                local $/ = \$reclen;

                my $io = $UncompressClass->new($name);
                is $., 0; 
                is $io->input_line_number, 0; 

                ok ! $io->eof;
                my @lines = $io->getlines();
                is $., $expected_records; 
                is $io->input_line_number, $expected_records; 
                ok $io->eof;
                is @lines, $expected_records, 
                    "Got $expected_records records\n" ;
                ok $lines[0] eq substr($str, 0, $reclen)
                    or print "# $lines[0]\n";
                ok $lines[1] eq substr($str, $reclen, $reclen);
            }

            {
                local $/ = "is";
                my $io = $UncompressClass->new($name);
                my @lines = ();
                my $no = 0;
                my $err = 0;
                ok ! $io->eof;
                while (my $a = $io->getline) {
                    push(@lines, $a);
                    $err++ if $. != ++$no;
                }
            
                is $., 3; 
                is $io->input_line_number, 3; 
                ok $err == 0 ;
                ok $io->eof;
            

                ok @lines == 3 ;
                ok join("-", @lines) eq
                                 "This- is- an example\n" .
                                "of a paragraph\n\n\n" .
                                "and a single line.\n\n";
            }
            
            
            # Test Read
            
            {
                my $io = $UncompressClass->new($name);
            
                $buf = "abcd";
                is $io->read($buf, 0), 0, "Requested 0 bytes" ;
                is $buf, "", "Buffer empty";

                ok $io->read($buf, 3) == 3 ;
                ok $buf eq "Thi";
            
                ok $io->sysread($buf, 3, 2) == 3 ;
                ok $buf eq "Ths i";
                ok ! $io->eof;
            
                $buf = "ab" ;
                is $io->read($buf, 3, 4), 3 ;
                is $buf, "ab" . "\x00" x 2 . "s a"
                    or print "# [$buf]\n" ;;
                ok ! $io->eof;
            
                # read the rest of the file
                $buf = '';
                my $remain = length($str) - 9;
                is $io->read($buf, $remain), $remain ;
                is $buf, substr($str, 9);
                ok $io->eof;

                $buf = "hello";
                is $io->read($buf, 10), 0 ;
                is $buf, "", "Buffer empty";
                ok $io->eof;

                ok $io->close();
                $buf = "hello";
                is $io->read($buf, 10), 0 ;
                is $buf, "hello", "Buffer not empty";
                ok $io->eof;

        #        $io->seek(-4, 2);
        #    
        #        ok ! $io->eof;
        #    
        #        ok read($io, $buf, 20) == 4 ;
        #        ok $buf eq "e.\n\n";
        #    
        #        ok read($io, $buf, 20) == 0 ;
        #        ok $buf eq "";
        #    
        #        ok ! $io->eof;
            }


        }

        {
            # Vary the length parameter in a read

            my $str = <<EOT;
x
x
This is an example
of a paragraph


and a single line.

EOT
            $str = $str x 100 ;


            foreach my $bufsize (1, 3, 512, 4096, length($str)-1, length($str), length($str)+1)
            {
                foreach my $trans (0, 1)
                {
                    foreach my $append (0, 1)
                    {
                        title "Read Tests - buf length $bufsize, Transparent $trans, Append $append" ;

                        my $lex = new LexFile my $name ;

                        if ($trans) {
                            writeFile($name, $str) ;
                        }
                        else {
                            my $iow = new $CompressClass $name;
                            $iow->print($str) ;
                            $iow->close ;
                        }

                        
                        my $io = $UncompressClass->new($name, 
                                                       -Append => $append,
                                                       -Transparent  => $trans);
                    
                        my $buf;
                        
                        is $io->tell(), 0;

                        if ($append) {
                            1 while $io->read($buf, $bufsize) > 0;
                        }
                        else {
                            my $tmp ;
                            $buf .= $tmp while $io->read($tmp, $bufsize) > 0 ;
                        }
                        is length $buf, length $str;
                        ok $buf eq $str ;
                        ok ! $io->error() ;
                        ok $io->eof;
                    }
                }
            }
        }

        foreach my $file (0, 1)
        {
            foreach my $trans (0, 1)
            {
                title "seek tests - file $file trans $trans" ;

                my $buffer ;
                my $buff ;
                my $lex = new LexFile my $name ;

                my $first = "beginning" ;
                my $last  = "the end" ;

                if ($trans)
                {
                    $buffer = $first . "\x00" x 10 . $last;
                    writeFile($name, $buffer);
                }
                else
                {
                    my $output ;
                    if ($file)
                    {
                        $output = $name ;
                    }
                    else
                    {
                        $output = \$buffer;
                    }

                    my $iow = new $CompressClass $output ;
                    $iow->print($first) ;
                    ok $iow->seek(5, SEEK_CUR) ;
                    ok $iow->tell() == length($first)+5;
                    ok $iow->seek(0, SEEK_CUR) ;
                    ok $iow->tell() == length($first)+5;
                    ok $iow->seek(length($first)+10, SEEK_SET) ;
                    ok $iow->tell() == length($first)+10;

                    $iow->print($last) ;
                    $iow->close ;
                }

                my $input ;
                if ($file)
                {
                    $input = $name ;
                }
                else
                {
                    $input = \$buffer ;
                }

                ok myGZreadFile($input) eq $first . "\x00" x 10 . $last ;

                my $io = $UncompressClass->new($input, Strict => 1);
                ok $io->seek(length($first), SEEK_CUR) 
                    or diag $$UnError ;
                ok ! $io->eof;
                is $io->tell(), length($first);

                ok $io->read($buff, 5) ;
                is $buff, "\x00" x 5 ;
                is $io->tell(), length($first) + 5;

                ok $io->seek(0, SEEK_CUR) ;
                my $here = $io->tell() ;
                is $here, length($first)+5;

                ok $io->seek($here+5, SEEK_SET) ;
                is $io->tell(), $here+5 ;
                ok $io->read($buff, 100) ;
                ok $buff eq $last ;
                ok $io->eof;
            }
        }

        {
            title "seek error cases" ;

            my $b ;
            my $a = new $CompressClass(\$b)  ;

            ok ! $a->error() 
                or die $a->error() ;
            eval { $a->seek(-1, 10) ; };
            like $@, mkErr("^${CompressClass}::seek: unknown value, 10, for whence parameter");

            eval { $a->seek(-1, SEEK_END) ; };
            like $@, mkErr("^${CompressClass}::seek: cannot seek backwards");

            $a->write("fred");
            $a->close ;


            my $u = new $UncompressClass(\$b)  ;

            eval { $u->seek(-1, 10) ; };
            like $@, mkErr("^${UncompressClass}::seek: unknown value, 10, for whence parameter");

            eval { $u->seek(-1, SEEK_END) ; };
            like $@, mkErr("^${UncompressClass}::seek: SEEK_END not allowed");

            eval { $u->seek(-1, SEEK_CUR) ; };
            like $@, mkErr("^${UncompressClass}::seek: cannot seek backwards");
        }
        
        foreach my $fb (qw(filename buffer filehandle))
        {
            foreach my $append (0, 1)
            {
                {
                    title "$CompressClass -- Append $append, Output to $fb" ;

                    my $lex = new LexFile my $name ;

                    my $already = 'already';
                    my $buffer = $already;
                    my $output;

                    if ($fb eq 'buffer')
                      { $output = \$buffer }
                    elsif ($fb eq 'filename')
                    {
                        $output = $name ;
                        writeFile($name, $buffer);
                    }
                    elsif ($fb eq 'filehandle')
                    {
                        $output = new IO::File ">$name" ;
                        print $output $buffer;
                    }

                    my $a = new $CompressClass($output, Append => $append)  ;
                    ok $a, "  Created $CompressClass";
                    my $string = "appended";
                    $a->write($string);
                    $a->close ;

                    my $data ; 
                    if ($fb eq 'buffer')
                    {
                        $data = $buffer;
                    }
                    else
                    {
                        $output->close
                            if $fb eq 'filehandle';
                        $data = readFile($name);
                    }

                    if ($append || $fb eq 'filehandle')
                    {
                        is substr($data, 0, length($already)), $already, "  got prefix";
                        substr($data, 0, length($already)) = '';
                    }


                    my $uncomp;
                    my $x = new $UncompressClass(\$data, Append => 1)  ;
                    ok $x, "  created $UncompressClass";

                    my $len ;
                    1 while ($len = $x->read($uncomp)) > 0 ;

                    $x->close ;
                    is $uncomp, $string, '  Got uncompressed data' ;
                    
                }
            }
        }

        foreach my $type (qw(buffer filename filehandle))
        {
            foreach my $good (0, 1)
            {
                title "$UncompressClass -- InputLength, read from $type, good data => $good";

                my $compressed ; 
                my $string = "some data";
                my $appended = "append";

                if ($good)
                {
                    my $c = new $CompressClass(\$compressed);
                    $c->write($string);
                    $c->close();
                }
                else
                {
                    $compressed = $string ;
                }

                my $comp_len = length $compressed;
                $compressed .= $appended;

                my $lex = new LexFile my $name ;
                my $input ;
                writeFile ($name, $compressed);

                if ($type eq 'buffer')
                {
                    $input = \$compressed;
                }
                if ($type eq 'filename')
                {
                    $input = $name;
                }
                elsif ($type eq 'filehandle')
                {
                    my $fh = new IO::File "<$name" ;
                    ok $fh, "opened file $name ok";
                    $input = $fh ;
                }

                my $x = new $UncompressClass($input, 
                                             InputLength => $comp_len,
                                             Transparent => 1)  ;
                ok $x, "  created $UncompressClass";

                my $len ;
                my $output;
                $len = $x->read($output, 100);

                is $len, length($string);
                is $output, $string;

                if ($type eq 'filehandle')
                {
                    my $rest ;
                    $input->read($rest, 1000);
                    is $rest, $appended;
                }
            }


        }
        
        foreach my $append (0, 1)
        {
            title "$UncompressClass -- Append $append" ;

            my $lex = new LexFile my $name ;

            my $string = "appended";
            my $compressed ; 
            my $c = new $CompressClass(\$compressed);
            $c->write($string);
            $c->close();

            my $x = new $UncompressClass(\$compressed, Append => $append)  ;
            ok $x, "  created $UncompressClass";

            my $already = 'already';
            my $output = $already;

            my $len ;
            $len = $x->read($output, 100);
            is $len, length($string);

            $x->close ;

            if ($append)
            {
                is substr($output, 0, length($already)), $already, "  got prefix";
                substr($output, 0, length($already)) = '';
            }
            is $output, $string, '  Got uncompressed data' ;
        }
        

        foreach my $file (0, 1)
        {
            foreach my $trans (0, 1)
            {
                title "ungetc, File $file, Transparent $trans" ;

                my $lex = new LexFile my $name ;

                my $string = 'abcdeABCDE';
                my $b ;
                if ($trans)
                {
                    $b = $string ;
                }
                else
                {
                    my $a = new $CompressClass(\$b)  ;
                    $a->write($string);
                    $a->close ;
                }

                my $from ;
                if ($file)
                {
                    writeFile($name, $b);
                    $from = $name ;
                }
                else
                {
                    $from = \$b ;
                }

                my $u = $UncompressClass->new($from, Transparent => 1)  ;
                my $first;
                my $buff ;

                # do an ungetc before reading
                $u->ungetc("X");
                $first = $u->getc();
                is $first, 'X';

                $first = $u->getc();
                is $first, substr($string, 0,1);
                $u->ungetc($first);
                $first = $u->getc();
                is $first, substr($string, 0,1);
                $u->ungetc($first);

                is $u->read($buff, 5), 5 ;
                is $buff, substr($string, 0, 5);

                $u->ungetc($buff) ;
                is $u->read($buff, length($string)), length($string) ;
                is $buff, $string;

                is $u->read($buff, 1), 0;
                ok $u->eof() ;

                my $extra = 'extra';
                $u->ungetc($extra);
                ok ! $u->eof();
                is $u->read($buff), length($extra) ;
                is $buff, $extra;
                
                is $u->read($buff, 1), 0;
                ok $u->eof() ;

                # getc returns undef on eof
                is $u->getc(), undef;
                $u->close();

            }
        }

        {
            title "write tests - invalid data" ;

            #my $lex = new LexFile my $name1 ;
            my($Answer);

            #ok ! -e $name1, "  File $name1 does not exist";

            my @data = (
                [ '{ }',         "${CompressClass}::write: input parameter not a filename, filehandle, array ref or scalar ref" ], 
                [ '[ { } ]',     "${CompressClass}::write: input parameter not a filename, filehandle, array ref or scalar ref" ], 
                [ '[ [ { } ] ]', "${CompressClass}::write: input parameter not a filename, filehandle, array ref or scalar ref" ], 
                [ '[ "" ]',      "${CompressClass}::write: input filename is undef or null string" ], 
                [ '[ undef ]',   "${CompressClass}::write: input filename is undef or null string" ], 
                [ '[ \$Answer ]',"${CompressClass}::write: input and output buffer are identical" ], 
                #[ "not readable", 'xx' ], 
                # same filehandle twice, 'xx'
               ) ;

            foreach my $data (@data)
            {
                my ($send, $get) = @$data ;
                title "${CompressClass}::write( $send )";
                my($copy);
                eval "\$copy = $send";
                my $x = new $CompressClass(\$Answer);
                ok $x, "  Created $CompressClass object";
                eval { $x->write($copy) } ;
                #like $@, "/^$get/", "  error - $get";
                like $@, "/not a scalar reference /", "  error - not a scalar reference";
            }

    #        @data = (
    #            [ '[ $name1 ]',  "input file '$name1' does not exist" ], 
    #            #[ "not readable", 'xx' ], 
    #            # same filehandle twice, 'xx'
    #           ) ;
    #
    #        foreach my $data (@data)
    #        {
    #            my ($send, $get) = @$data ;
    #            title "${CompressClass}::write( $send )";
    #            my $copy;
    #            eval "\$copy = $send";
    #            my $x = new $CompressClass(\$Answer);
    #            ok $x, "  Created $CompressClass object";
    #            ok ! $x->write($copy), "  write fails"  ;
    #            like $$Error, "/^$get/", "  error - $get";
    #        }

            #exit;
            
        }


    #    sub deepCopy
    #    {
    #        if (! ref $_[0] || ref $_[0] eq 'SCALAR')
    #        {
    #            return $_[0] ;
    #        }
    #
    #        if (ref $_[0] eq 'ARRAY')
    #        {
    #            my @a ;
    #            for my $x ( @{ $_[0] })
    #            {
    #                push @a, deepCopy($x);
    #            }
    #
    #            return \@a ;
    #        }
    #
    #        croak "bad! $_[0]";
    #
    #    }
    #
    #    sub deepSubst
    #    {
    #        #my $data = shift ;
    #        my $from = $_[1] ;
    #        my $to   = $_[2] ;
    #
    #        if (! ref $_[0])
    #        {
    #            $_[0] = $to 
    #                if $_[0] eq $from ;
    #            return ;    
    #
    #        }
    #
    #        if (ref $_[0] eq 'SCALAR')
    #        {
    #            $_[0] = \$to 
    #                if defined ${ $_[0] } && ${ $_[0] } eq $from ;
    #            return ;    
    #
    #        }
    #
    #        if (ref $_[0] eq 'ARRAY')
    #        {
    #            for my $x ( @{ $_[0] })
    #            {
    #                deepSubst($x, $from, $to);
    #            }
    #            return ;
    #        }
    #        #croak "bad! $_[0]";
    #    }

    #    {
    #        title "More write tests" ;
    #
    #        my $file1 = "file1" ;
    #        my $file2 = "file2" ;
    #        my $file3 = "file3" ;
    #        my $lex = new LexFile $file1, $file2, $file3 ;
    #
    #        writeFile($file1, "F1");
    #        writeFile($file2, "F2");
    #        writeFile($file3, "F3");
    #
    #        my @data = (
    #              [ '""',                                   ""      ],
    #              [ 'undef',                                ""      ],
    #              [ '"abcd"',                               "abcd"  ],
    #
    #              [ '\""',                                   ""     ],
    #              [ '\undef',                                ""     ],
    #              [ '\"abcd"',                               "abcd" ],
    #
    #              [ '[]',                                    ""     ],
    #              [ '[[]]',                                  ""     ],
    #              [ '[[[]]]',                                ""     ],
    #              [ '[\""]',                                 ""     ],
    #              [ '[\undef]',                              ""     ],
    #              [ '[\"abcd"]',                             "abcd" ],
    #              [ '[\"ab", \"cd"]',                        "abcd" ],
    #              [ '[[\"ab"], [\"cd"]]',                    "abcd" ],
    #
    #              [ '$file1',                                $file1 ],
    #              [ '$fh2',                                  "F2"   ],
    #              [ '[$file1, \"abc"]',                      "F1abc"],
    #              [ '[\"a", $file1, \"bc"]',                 "aF1bc"],
    #              [ '[\"a", $fh1, \"bc"]',                   "aF1bc"],
    #              [ '[\"a", $fh1, \"bc", $file2]',           "aF1bcF2"],
    #              [ '[\"a", $fh1, \"bc", $file2, $fh3]',     "aF1bcF2F3"],
    #            ) ;
    #
    #
    #        foreach my $data (@data)
    #        {
    #            my ($send, $get) = @$data ;
    #
    #            my $fh1 = new IO::File "< $file1" ;
    #            my $fh2 = new IO::File "< $file2" ;
    #            my $fh3 = new IO::File "< $file3" ;
    #
    #            title "${CompressClass}::write( $send )";
    #            my $copy;
    #            eval "\$copy = $send";
    #            my $Answer ;
    #            my $x = new $CompressClass(\$Answer);
    #            ok $x, "  Created $CompressClass object";
    #            my $len = length $get;
    #            is $x->write($copy), length($get), "  write $len bytes";
    #            ok $x->close(), "  close ok" ;
    #
    #            is myGZreadFile(\$Answer), $get, "  got expected output" ;
    #            cmp_ok $$Error, '==', 0, "  no error";
    #
    #
    #        }
    #        
    #    }
    }

    {
        # Check can handle empty compressed files
        # Test is for rt.cpan #67554

        foreach my $type (qw(filename filehandle buffer ))
        {
            foreach my $append (0, 1)
            {
                title "$UncompressClass -- empty file read from $type, Append => $append";

                my $appended = "append";
                my $string = "some data";
                my $compressed ; 

                my $c = new $CompressClass(\$compressed);
                $c->close();

                my $comp_len = length $compressed;
                $compressed .= $appended if $append && $CompressClass !~ /zstd/i;

                my $lex = new LexFile my $name ;
                my $input ;
                writeFile ($name, $compressed);

                if ($type eq 'buffer')
                {
                    $input = \$compressed;
                }
                elsif ($type eq 'filename')
                {
                    $input = $name;
                }
                elsif ($type eq 'filehandle')
                {
                    my $fh = new IO::File "<$name" ;
                    ok $fh, "opened file $name ok";
                    $input = $fh ;
                }

                {
                    # Check that eof is true immediately after creating the
                    # uncompression object.

                    # Check that readline returns undef

                    my $x = new $UncompressClass $input, Transparent => 0
                        or diag "$$UnError" ;
                    isa_ok $x, $UncompressClass;

                    # should be EOF immediately
                    is $x->eof(), 1, "eof true";

                    is <$x>, undef, "getline is undef";

                    is $x->eof(), 1, "eof true";
                }

                {
                    # Check that read returns an empty string
                    if ($type eq 'filehandle')
                    {
                        my $fh = new IO::File "<$name" ;
                        ok $fh, "opened file $name ok";
                        $input = $fh ;
                    }

                    my $x = new $UncompressClass $input, Transparent => 0 
                        or diag "$$UnError" ;
                    isa_ok $x, $UncompressClass;

                    my $buffer;
                    is $x->read($buffer), 0, "read 0 bytes"
                        or diag "read returned $$UnError";
                    ok defined $buffer, "buffer is defined";
                    is $buffer, "", "buffer is empty string";

                    is $x->eof(), 1, "eof true";
                }

                {
                    # Check that read return an empty string in Append Mode
                    # to empty string

                    if ($type eq 'filehandle')
                    {
                        my $fh = new IO::File "<$name" ;
                        ok $fh, "opened file $name ok";
                        $input = $fh ;
                    }
                    my $x = new $UncompressClass $input, Transparent => 0,
                                                         Append => 1 
                        or diag "$$UnError" ;
                    isa_ok $x, $UncompressClass;

                    my $buffer;
                    is $x->read($buffer), 0, "read 0 bytes";
                    ok defined $buffer, "buffer is defined";
                    is $buffer, "", "buffer is empty string";

                    is $x->eof(), 1, "eof true";
                }
                {
                    # Check that read return an empty string in Append Mode
                    # to non-empty string

                    if ($type eq 'filehandle')
                    {
                        my $fh = new IO::File "<$name" ;
                        ok $fh, "opened file $name ok";
                        $input = $fh ;
                    }
                    my $x = new $UncompressClass($input, Append => 1 );
                    isa_ok $x, $UncompressClass;

                    my $buffer = "123";
                    is $x->read($buffer), 0, "read 0 bytes";
                    ok defined $buffer, "buffer is defined";
                    is $buffer, "123", "buffer orig string";

                    is $x->eof(), 1, "eof true";
                }
            }
        }
    }

    {
        # Round trip binary data that happens to contain \r\n
        # via the filesystem

        my $original = join '', map { chr } 0x00 .. 0xff ;
        $original .= "data1\r\ndata2\r\ndata3\r\n" ;
        
   
        title "$UncompressClass -- round trip test";

        my $string = $original;

        my $lex = new LexFile( my $name, my $compressed) ;
        my $input ;
        writeFile ($name, $original);

        my $c = new $CompressClass($compressed);
        isa_ok $c, $CompressClass;
        $c->print($string);
        $c->close();

        my $u = new $UncompressClass $compressed, Transparent => 0
            or diag "$$UnError" ;
        isa_ok $u, $UncompressClass;
        my $buffer;
        is $u->read($buffer), length($original), "read bytes";
        is $buffer, $original, "  round tripped ok";

        
    }    
}

1;