use strict;
use warnings;

use Benchmark  qw{ cmpthese };
use Test::More qw{ no_plan };

open my $inFH, q{<}, \ <<__EOD__ or die $!;
TATCGC.TGCCC.ATTAAGCCATACTTCAAGGATCCCCCCG.GA.GGGCA
GGAGTCGTC.ACACATCTTCACTAC.CATATCTTGCTACGGCCACTGACA
CGA.A.CAATTTTCGAATGGAGGGCGAATGCCGTTGTGCGCTGCGTGACG
TCT.AGCCT.CGAA.A.GCAGGCGTGGGGCGTACCACGGCTTGGCCTAT.
ATGCACTT.AA.CCCTCGTAT.CTCTACTCT.ACAACCTTGGGCAG.T.T
TAGGGC.CCGCG.TAAACTGCAGATAGTACTCCAAGAATCGCTCCGACCC
.CGTCTAAACAATTAGCGGAGGTCGTC.CTGCAA.CAATGATCTTAACAC
AG.AAGAAGT.CAAAGT.GTAGTGGCTGGGTACTTGATCA.TCAATTTCA
ACC.TTCCAG.AAATGAGGTCTC.AAAAG.AGTT.CCTG.GGCTGTGTAG
ACAT.A.TGTTAACACCACCTATAATAGAAGC.TTATATTCACC.TTAAC
GAATTGT.TTCAATGCCACATA.GCTGGGCCAC.GCCTTAGGCTATTT.A
AGCTTTACAGATGT.ACCAAA.CCAG.GACTAGATGGGGGGG.ATATGCC
AGAAAGCCC.TCCCTGCGAAT.TGGGGGAGTACT.ATAGACTA.GGCCAG
.CACTCCGG.CTAACACTACTTCCTGTAACAAA.CTGAAGAGA.CGTTTG
CAGTCCTGAGCGTGCTAC..GTTCT.CTGTCG.TTAGATGGGCGC..GTA
AGCAAGAAAACACGTACAGAAAAAGCCGACGGC.GGGGTTC.GTCAACC.
T.ACTTATCGACATTAGCATCTGG.TGCCGCCTTT.GAACCCATTACTCG
TAAACGA.CACCGCTTAGGGCTGACCTCCGAA.TTATCAGAGTACCGGGC
ACGGATATCCTA.ATAGA.TACCTATGTAGGAAG.TCGAACTC.TAAACT
ACCCCCGTCC.TATCCTC.CGA.ATTGCCCCCGGCCGTACTCCA.AAACC
T..TC.AGCCGGG.TTG.TGTGGATCAGAAGTGATTGAGACTGG.GCCTA
TCAACCTTGAAGTTGAAACTCCGAGAGT.CGCGGTCAACC.AGCCTGCGC
GATCAGTGAGGAGCTGT.C.AAAGC.TC.AG.GCC.G.GA.GTGAGATT.
G.C.AGTTTGCCACTT.CATCCAGAGTTCATCCAGCAGG.ATTGAAGTTA
GCGCTGCA.CTGT.CATTTTTTATTCCCACCCGGTCTCCCCAACCCCGAT
TGTATAGCCAGG.CGGAG.TTTCTT.TAGATCTAGTAAGACATT.CCCGA
AC.CCCCT.G.TAGCTAAATCGACGGG..GTCAATATACACGGAT.CTTT
AAGC.GGGCTGATGCTTATCTCCTAGCCCGC.CCTCGATGAT.ATTATTG
TCACCC.ACCGC..T.CGGAACGAAAACT..AT.CCTATTAGAACATCCT
.GCGTGAACC.TG.G.TACACCG.GATGGTCCCGAC.GGCTACCGAT.CA
.CGCTGCCCCCATCTCCAGCTATC.AAA.AGGGACGCGATATGCGGAAGC
CGTTCAGACAATCCTTTTGGGGTGTAAATGTCTCC.ACCTC.GAGA.CTG
AAGACATAGGAG.CCAGAAT.A.CGTCATACAGAGGCACTC.TAT..TCT
AGGCCTGCCTACTT.TTGGCTAA.C.AGACTTGG.AAG.ATGTAGAAC.G
GTCAACCCGTGCTAACTGGGGTGAGGAATCTTCCGAGCC.TGCTCGTCGC
TCG.TGGCAGCTC.AACTGGTGCGCGGCAG.CCTCCTGCCAAGTATTCAG
CGGGGGCTAC..GTT.TCATCGAACACGGCACACTAACAAACTCCTGTGT
TTCCGGGGTCGACCCTTTGGCCCAAGAGTGA.AGGGCTTCG.ACTGCG..
AA.CGTGCGGGTAGCCTAGACACGTAGC.TTGTGCGC.CG.CGCA.CAAG
AT.TATGTCA.ACTTCCGCCGGG.CTTCTGTGTACATT.AA.GAGAATAA
CGGCAAGGATTGCTCGACGTAGGAGTCCGTGGAGCTCGTGC.GACC.ACC
.GTTAA.CACGCCTTAACTTTTCGGAACAGAGTAAC.AATCCCGG.TA.C
CAGGTAATGTGTCACCAGGTTCGGGCCCT.CACCGTCCCAGCTAC.TGTT
TAGCCCCTCTTTT.GAT.GGCCC.AGCGACATCAA.TGATC..CTGTAGG
CGATCATATTTCATTGTTCCGC.TG.AGCGGT.A.TG.GCAAT.CAGCCG
ATCGATGTTCTGATATG..GTGTGAATAC.AGAAACCGGCTTTGTCGGGG
CCTTT.AGGAA.AC.TAGGT.TT.CTCAATGAAC.GACATCAAC.T.AGC
AAGGAGGTACACAGCGTTCAGCGGATCC.CT.AAGC.TAGCATCTGCTGA
GCAGATA.A.TCTGCTTCAACTGTGAAAGGGTTG.CTAATCAG.GCGTAG
GGTACGATC.GCAAC.AGTCCACAAGTACACGGTGGAATT.CC..C.TTG
__EOD__

my $fileStart = tell $inFH;

my $offset = 9;    # Column 10 if numbering from 1

my $testOK = q{C.T.AGCTGTTG..GAGACCCAGGCAGTCCCAGTTGCCGATCTTTCAC..};

my %methods = (
   rsubstr => sub { # BrowserUk's method
       seek $inFH, 0, 0;

       my $buffer;
       my $rsWanted = \ substr $buffer, $offset, 1;
       my $retStr;
       while ( $buffer = <$inFH> )
       {
           $retStr .= ${ $rsWanted };
       }

       return \ $retStr;
   },
   brutish => sub { # Adapted from Anonymonk's brute force method
       seek $inFH, 0, 0;

       my $retStr;
       while ( <$inFH> )
       {
           my @split = split m{};
           $retStr .= $split[ $offset ];
       }

       return \ $retStr;
   },
   seek    => sub { # Suggested by vr
       seek $inFH, 0, 0;

       my $retStr;
       my $char;
       my $len = length( <$inFH> ) - 1;
       seek $inFH, $offset, 0;
       while ( read $inFH, $char, 1 )
       {
           $retStr .= $char;
           seek $inFH, $len, 1
       }

       return \ $retStr;
   },
   substr  => sub { # Suggested by pryrt and Laurent_R
       seek $inFH, 0, 0;

       my $retStr;
       while ( <$inFH> )
       {
           $retStr .= substr $_, $offset, 1;
       }

       return \ $retStr;
   },
   regex   => sub { # Another of pryrt's solutions
       seek $inFH, 0, 0;

       my $retStr;
       while ( <$inFH> )
       {
           $retStr .= $1 if m{^.{$offset}(.)};
       }

       return \ $retStr;
   },
   unpack  => sub { # Suggested but not implemented by LanX & pryrt
       seek $inFH, 0, 0;

       my $retStr;
       my $fmt = qq{x${offset}a};
       while ( <$inFH> )
       {
           $retStr .= unpack $fmt, $_;
       }

       return \ $retStr;
   },
   unpackM => sub { # Multi-line unpack suggested by LanX
       seek $inFH, 0, 0;

       my $buffer     = <$inFH>;
       my $lineLen    = length $buffer;
       my $nLines     = 500;
       my $chunkSize  = $lineLen * $nLines;

       seek $inFH, 0, 0;

       my $retStr;
       my $fmt = qq{(x${offset}ax@{ [ $lineLen - $offset - 1 ] })*};
       while ( my $bytesRead = read $inFH, $buffer, $chunkSize )
       {
           $retStr .= join q{}, unpack $fmt, $buffer;
       }

       return \ $retStr;
   },
   split   => sub { # Simple split from thanos1983
       seek $inFH, 0, 0;

       my $retStr;
       my $fmt = qq{x${offset}a};
       while ( <$inFH> )
       {
           $retStr .= ( split m{} )[ $offset ];
       }

       return \ $retStr;
   },
   pushAoA => sub { # In memory solution from Discipulus
       seek $inFH, 0, 0;

       my @aoa;
       while ( <$inFH> )
       {
           chomp;
           push @aoa, [ split m{} ];
       }
       my $retStr = join q{}, map { $aoa[ $_ ]->[ $offset ] } 0 .. $#aoa;

       return \ $retStr;
   },
   ANDmask => sub { # Multi-line AND mask by johngg
       seek $inFH, 0, 0;

       my $buffer     = <$inFH>;
       my $lineLen    = length $buffer;
       my $nLines     = 500;
       my $chunkSize  = $lineLen * $nLines;

       seek $inFH, 0, 0;

       my $retStr;
       my $mask
          = qq{\x00} x ${offset}
          . qq{\xff}
          . qq{\x00} x ( $lineLen - $offset - 1 );
       $mask x= $nLines;
       while ( my $bytesRead = read $inFH, $buffer, $chunkSize )
       {
           ( my $anded = $buffer & $mask ) =~ tr{\x00}{}d;
           $retStr .= $anded;
       }

       return \ $retStr;
   },
   );

foreach my $method ( sort keys %methods )
{
    ok( ${ $methods{ $method }->() } eq $testOK, $method );
}

close $inFH or die $!;

my $filename = q{spw1202693.txt};
open $inFH, q{<}, $filename
   or die qq{open: < $filename: $!\n};

cmpthese(
   -3,
   {
       map
       {
           my $codeStr
              = q[sub { my $col = $methods{ ]
              . $_
              . q[ }->(); }];
           $_ => eval $codeStr;
       }
       keys %methods
   }
   );

close $inFH
   or die qq{close: < $filename: $!\n};