This file is indexed.

/usr/bin/vcf-merge is in vcftools 0.1.15-1.

This file is owned by root:root, with mode 0o755.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
#!/usr/bin/env perl
#
# Author: petr.danecek@sanger
#

use strict;
use warnings;
use Carp;
use Vcf;

my $opts = parse_params();
merge_vcf_files($opts);

exit;

#--------------------------------

sub error
{
    my (@msg) = @_;
    if ( scalar @msg ) { croak join('',@msg); }
    die
        "About: Merges VCF files by position, creating multi-sample VCFs from fewer-sample VCFs.\n",
        "   The tool requires bgzipped and tabix indexed VCF files on input. (E.g. bgzip file.vcf; tabix -p vcf file.vcf.gz)\n",
        "   If you need to concatenate VCFs (e.g. files split by chromosome), look at vcf-concat instead.\n",
        "Usage: vcf-merge [OPTIONS] file1.vcf file2.vcf.gz ... > out.vcf\n",
        "Options:\n",
        "   -c, --collapse <snps|indels|both|any|none>      treat as identical sites with differing alleles [any]\n",
        "   -d, --remove-duplicates                         If there should be two consecutive rows with the same chr:pos, print only the first one.\n",
        "   -H, --vcf-header <file>                         Use the provided VCF header\n",
        "   -h, -?, --help                                  This help message.\n",
        "   -r, --regions <list|file>                       Do only the given regions (comma-separated list or one region per line in a file).\n",
        "   -R, --ref-for-missing <string>                  Use the REF allele instead of the default missing genotype. Because it is not obvious\n",
        "                                                       what ploidy should be used, a user-defined string is used instead (e.g. 0/0).\n",
        "   -s, --silent                                    Try to be a bit more silent, no warnings about duplicate lines.\n",
        "   -t, --trim-ALTs                                 If set, redundant ALTs will be removed\n",
        "\n";
}


sub parse_params
{
    $0 =~ s{^.+/}{}; $0 .= "($Vcf::VERSION)";
    my $opts = 
    { 
        args => [$0, @ARGV],
        joiner => 
        {
            'I16' => \&joiner_dp4,
            'DP4' => \&joiner_dp4,
            'MQ0'  => \&joiner_sum,
            'DP'  => \&joiner_sum,
        },
        trim_redundant_ALTs => 0,
        collapse_any => 1,
    };
    while (my $arg=shift(@ARGV))
    {
        if ( $arg eq '-d' || $arg eq '--remove-duplicates' ) { $$opts{rm_dups}=1; next; }
        if ( $arg eq '-R' || $arg eq '--ref-for-missing' ) { $$opts{ref_for_missing}=shift(@ARGV); next; }
        if ( $arg eq '-t' || $arg eq '--trim-ALTs' ) { $$opts{trim_redundant_ALTs}=1; next; }
        if ( $arg eq '-s' || $arg eq '--silent' ) { $$opts{silent_dups}=1; next; }
        if ( $arg eq '-H' || $arg eq '--vcf-header' ) { $$opts{vcf_header}=shift(@ARGV); next; }
        if ( $arg eq '-c' || $arg eq '--collapse' ) 
        {
            $$opts{collapse_any} = 0;
            my $c = shift(@ARGV);
            if ( $c eq 'snps' ) { $$opts{collapse_snps}=1; }
            elsif ( $c eq 'indels' ) { $$opts{collapse_indels}=1; }
            elsif ( $c eq 'both' ) { $$opts{collapse_snps}=1; $$opts{collapse_indels}=1; }
            elsif ( $c eq 'any' ) { $$opts{collapse_any}=1; }
            elsif ( $c eq 'none' ) { $$opts{collapse_any}=0; $$opts{collapse_snps}=0; $$opts{collapse_indels}=0; }
            else { error("Expected one of <snps|indels|both|any> with -c"); }
            next; 
        }
        if ( $arg eq '-r' || $arg eq '--regions' ) { $$opts{regions_list}=shift(@ARGV); next; }
        if ( $arg eq '-?' || $arg eq '-h' || $arg eq '--help' ) { error(); }
        if ( -e $arg ) { push @{$$opts{files}},$arg; next; }
        error("Unknown parameter or non-existent file \"$arg\". Run -? for help.\n");
    }
    if ( !exists($$opts{files}) ) { error() }
    return $opts;
}


# Returns the common prefix of the files.
sub common_prefix
{
    my ($files) = @_;
    my @paths;
    my $len = -1;
    for my $file (@$files)
    {
        my @path = split(m{/+},$file);
        if ( $len<0 || $len>scalar @path ) { $len=scalar @path; }
        push @paths, \@path;
    }
    my @common;
    for (my $i=0; $i<$len; $i++)
    {
        my $identical=1;
        for (my $ifile=1; $ifile<scalar @paths; $ifile++)
        {
            if ( $paths[$ifile]->[$i] ne $paths[0]->[$i] ) { $identical=0; last; }
        }
        if ( !$identical ) { last; }
        push @common, $paths[0]->[$i];
    }
    return join('/+',@common);
}


sub read_region_list
{
    my ($opts) = @_;

    my @regions = ();
    if ( exists($$opts{regions_list}) ) 
    { 
        if ( -e $$opts{regions_list} )
        {
            open(my $rgs,'<',$$opts{regions_list}) or error("$$opts{regions_list}: $!");
            while (my $line=<$rgs>)
            {
                chomp($line);
                push @regions, $line;
            }
            close($rgs);
        }
        else
        {
            @regions = split(/,/,$$opts{regions_list}); 
        }
    }
    return (@regions);
}

sub check_AGtags_definition
{
    my ($vcf) = @_;
    if ( $$vcf{version} >= 4.1 ) { return; }

    # Whatever is the value set to, the user takes the responsibility for the merging strategy used
    if ( exists($ENV{DONT_FIX_VCF40_AG_TAGS}) ) { return; }

    my @tags;
    if ( exists($$vcf{header}{INFO}{PL}) && $$vcf{header}{INFO}{PL}{Number} != -1  ) { push @tags, 'PL'; }
    if ( exists($$vcf{header}{INFO}{GL}) && $$vcf{header}{INFO}{GL}{Number} != -1  ) { push @tags, 'GL'; }
    if ( exists($$vcf{header}{INFO}{AC}) && $$vcf{header}{INFO}{AC}{Number} != -1  ) { push @tags, 'AC'; }
    if ( exists($$vcf{header}{INFO}{AF}) && $$vcf{header}{INFO}{AF}{Number} != -1  ) { push @tags, 'AF'; }

    if ( !@tags ) { return; }

    $ENV{DONT_FIX_VCF40_AG_TAGS} = 1;
    my $tags = join(',',@tags);
    print STDERR 
        "Warning: The $tags tag(s) will not be merged correctly for multiallelic sites.\n",
        "   To be handled correctly, please redefine with Number=. or set the environment\n",
        "   variable DONT_FIX_VCF40_AG_TAGS=0.\n";
}

sub init_cols
{
    my ($opts,$vcf_out) = @_;

    my $prefix;
    my @regions = read_region_list($opts);
    my @vcfs;
    my @cols;
    my %has_chrom;
    my %col_names;
    my $icol = 9;
    my $ncols_total = 0;

    if ( !$$opts{has_col_names} ) { $prefix = common_prefix($$opts{files}); }

    # Go through all files and read header, obtain list of chromosomes. The file names will be used for columns, unless
    #   they were read from the header.
    for my $file (@{$$opts{files}})
    {
        my $vcf = Vcf->new(file=>$file);
        $$vcf{line_buffer} = [];
        $vcf->parse_header();
        check_AGtags_definition($vcf);
        $vcf->close();
        push @vcfs, $vcf;

        # Precompute the weighting factor for the QUAL column
        my $ncols = scalar @{$$vcf{columns}} - 9;
        if ( $ncols<=0 ) { $ncols = 1; }
        $$vcf{qual_weight} = 1.0*$ncols;
        $ncols_total += $ncols;

        # Update the list of known chromosomes
        if ( !exists($$opts{regions_list}) )
        {
            my $chrms = $vcf->get_chromosomes();
            for my $chr (@$chrms)
            {
                if ( exists($has_chrom{$chr}) ) { next; }
                $has_chrom{$chr} = 1;
                push @regions, $chr;
            }
        }

        my $col_prefix = '';
        if ( !$$opts{has_col_names} )
        {
            # Make the column names nice - strip common prefix and the suffix .vcf.gz
            $col_prefix = $file; 
            $col_prefix =~ s{^/*$prefix/*}{};
            $col_prefix =~ s/\.gz$//i;
            $col_prefix =~ s/\.vcf$//i;
            $col_prefix .= '_';
        }

        if ( !exists($$vcf{columns}) ) { error("No header present? $file\n"); }

        # Create good names for the columns in the merged vcf file
        my @vcf_cols = @{$$vcf{columns}};
        $$vcf{__col_names} = [];
        for my $col (@vcf_cols[9..$#vcf_cols])
        {
            my $col_name = $col;
            if ( $$opts{has_col_names} ) 
            {
                if ( $icol >= @{$$vcf_out{columns}} ) { error("Fewer columns in the header than in the VCF files total.\n"); }
                $col_name = $$vcf_out{columns}[$icol];
                $icol++;

                if ( exists($col_names{$col_name}) ) { error("The column names not unique in the header: $col_name\n"); }
            }
            else
            {
                if ( exists($col_names{$col_name}) ) { $col_name = $col_prefix.$col; }
                if ( exists($col_names{$col_name}) ) { warn("FIXME: the column name [$col_name] not unique.\n"); }
            }
            warn("Using column name '$col_name' for $file:$col\n");
            $col_names{$col_name} = 1;

            push @cols, $col_name;
            push @{$$vcf{__col_names}}, $col_name;
        }
    }

    if ( $$opts{has_col_names} && $icol!=@{$$vcf_out{columns}} ) { error("More columns in the header than in the VCF files total.\n"); }

    # QUAL weighting
    for my $vcf (@vcfs)
    {
        $$vcf{qual_weight} /= $ncols_total;
    }

    $$opts{vcfs} = \@vcfs;
    $$opts{cols} = \@cols;
    $$opts{regions} = \@regions;
}


sub merge_vcf_files
{
    my ($opts) = @_;

    # Create output VCF
    my $vcf_out;
    if ( $$opts{vcf_header} )
    {
        $vcf_out = Vcf->new(file=>$$opts{vcf_header});
        $vcf_out->parse_header();
        if ( $$vcf_out{columns} && @{$$vcf_out{columns}} ) { $$opts{has_col_names}=1; }
    }
    else
    {
        $vcf_out = Vcf->new();
    }

    $$vcf_out{trim_redundant_ALTs} = $$opts{trim_redundant_ALTs};

    init_cols($opts,$vcf_out);
    my @regions = @{$$opts{regions}};
    my @cols    = @{$$opts{cols}};
    my @vcfs    = @{$$opts{vcfs}};

    # Get the header of the output VCF ready
    $vcf_out->add_columns(@cols);
    if ( !$$vcf_out{has_header} )
    {
        for my $vcf (@vcfs)
        {
            # To get the missig fields filled by the default values
            for my $hline (@{$$vcf{header_lines}})
            {
                if ( $$hline{key} eq 'fileformat' ) { next; }
                $vcf_out->add_header_line($hline,silent=>1);
            }
        }
    }

    # List source files
    my $source;
    for (my $i=0; $i<@vcfs; $i++)
    {
        if ( $i ) { $source .= ','; }
        $source .= "$i:$vcfs[$i]{file}";
    }
    $vcf_out->add_header_line({key=>'source',value=>join(' ',@{$$opts{args}})},append=>'timestamp');
    $vcf_out->add_header_line({key=>'sourceFiles',value=>$source},append=>'timestamp');
    $vcf_out->add_header_line({key=>'INFO',ID=>'SF',Number=>-1,Type=>'String',Description=>'Source File (index to sourceFiles, f when filtered)'});

    my $have_samples = @{$$vcf_out{columns}}>9 ? 1 : 0; 

    $vcf_out->recalc_ac_an($have_samples ? 2 : 0);
    $vcf_out->add_header_line({key=>'INFO',ID=>'AC',Number=>-1,Type=>'Integer',Description=>'Allele count in genotypes'});
    $vcf_out->add_header_line({key=>'INFO',ID=>'AN',Number=>1,Type=>'Integer',Description=>'Total number of alleles in called genotypes'});
    print $vcf_out->format_header();

    # Go through all VCF files simultaneously and output each line, one region at a time.
    for my $region (@regions)
    {
        # Open files
        for my $vcf (@vcfs) 
        { 
            delete($$vcf{done});
            $vcf->open(region=>$region); 
        }

        while ( my $pos=advance_position($opts,\@vcfs) )
        {
            my %out;
            $out{POS}    = $pos;
            $out{ID}     = '.';
            $out{ALT}    = [];
            $out{FORMAT} = [];
            my %format;
            my %info;
            my @src_files;
            my %filters;
            my (@quals,@qual_weights,$qual_weights_sum,%ac,$an);

            my %ref_alt_map = ();
            # Find out the REFs and ALTs: in VCFv4.0, the REFs can differ and ALTs must be converted
            for my $vcf (@vcfs)
            {
                my $line = $$vcf{last_line};
                if ( !$line ) { next; }
                if ( !exists($out{CHROM}) ) { $out{CHROM} = $$line{CHROM}; }
                my $ref = $$line{REF};
                for my $alt (@{$$line{ALT}}) { $ref_alt_map{$ref}{$alt}=$alt; }
            }
            # Do the REF,ALT conversion only when necessary
            my $new_ref; 
            if ( scalar keys %ref_alt_map > 1 ) 
            { 
                $new_ref = $vcf_out->fill_ref_alt_mapping(\%ref_alt_map); 
                if ( !defined $new_ref ) { error("Failed on line $out{CHROM}:$out{POS}\n"); }
            }
            if ( !$have_samples or !$$opts{trim_redundant_ALTs} )
            {
                # Do not loose information from the ALT column when samples are not present
                my %alts;
                for my $vcf (@vcfs)
                {
                    my $line = $$vcf{last_line};
                    if ( !$line ) { next; }
                    my $ref = $$line{REF};
                    for my $alt (@{$$line{ALT}}) { $alts{$ref_alt_map{$ref}{$alt}}=1; }
                    delete($alts{'.'});
                    $out{ALT} = [ keys %alts ];
                }
            }
            for (my $ivcf=0; $ivcf<@vcfs; $ivcf++)
            {
                my $vcf  = $vcfs[$ivcf];
                my $line = $$vcf{last_line};

                # If this file does not have a record for this position, then for all its columns output undef gtype
                if ( !$line )
                {
                    for (my $i=0; $i<@{$$vcf{__col_names}}; $i++)
                    {
                        my $name = $$vcf{__col_names}->[$i];
                        $out{gtypes}{$name}{GT} = exists($$opts{ref_for_missing}) ? $$opts{ref_for_missing} : $$vcf_out{defaults}{GT};
                    }
                    next;
                }

                # Check if the site has been filtered
                if ( scalar @{$$line{FILTER}}>1 or ($$line{FILTER}[0] ne $$vcf{filter_passed} && $$line{FILTER}[0] ne $$vcf{defaults}{default}) )
                {
                    push @src_files,$ivcf.'f';
                }
                else
                {
                    push @src_files,$ivcf;
                }

                # Collect information for the FILTER field
                for my $flt (@{$$line{FILTER}})
                {
                    if ( $flt eq $$vcf{filter_passed} )
                    {
                        $filters{$$vcf_out{filter_passed}} = 1;
                    }
                    elsif ( $flt ne $$vcf{defaults}{default} )
                    {
                        $filters{$flt} = 1;
                    }
                }

                # Collect information for the QUAL field
                if ( $$line{QUAL} ne $$vcf{defaults}{QUAL} && $$line{QUAL} ne $$vcf{defaults}{default} && $$line{QUAL}>0 )
                {
                    push @quals,$$line{QUAL};
                    push @qual_weights,$$vcf{qual_weight};
                    $qual_weights_sum += $$vcf{qual_weight};
                }

                if ( $$line{ID} ne '.' && $out{ID} eq '.' ) { $out{ID}=$$line{ID}; }

                # Remember the FORMAT fields
                for my $field (@{$$line{FORMAT}}) { $format{$field} = 1; }

                # VCF without genotypes: calculate AC,AN if present
                if ( !$have_samples )
                {
                    if ( exists($$line{INFO}{AN}) ) { $an += $$line{INFO}{AN}; }
                    if ( exists($$line{INFO}{AC}) ) 
                    { 
                        my (@acs) = split(/,/,$$line{INFO}{AC});
                        for (my $i=0; $i<@acs; $i++) 
                        { 
                            my $alt = $ref_alt_map{$$line{REF}}{$$line{ALT}[$i]};
                            $ac{$alt} += $acs[$i];
                        }
                    }
                }

                # Join the INFO field
                for my $inf (keys %{$$line{INFO}}) 
                {
                    # When conflicting INFO fields are present, use the first one, unless a joining method exists
                    if ( exists($info{$inf}) )
                    {
                        if ( exists($$opts{joiner}{$inf}) )
                        {
                            &{$$opts{joiner}{$inf}}(\$info{$inf},$$line{INFO}{$inf});
                        }
                        next;
                    }
                    $info{$inf} = $$line{INFO}{$inf};
                }

                my $ref = $$line{REF};

                # The ALT column may change after the merge, take care of ALT dependent tags such as GL.
                if ( $have_samples )
                {
                    if ( defined $new_ref )
                    {
                        $vcf->parse_AGtags($line,\%ref_alt_map,$$line{REF});
                    }
                    else
                    {
                        $vcf->parse_AGtags($line);
                    }
                }

                # Now fill in the genotype information for each column
                for (my $i=0; $i<@{$$vcf{__col_names}}; $i++)
                {
                    my $ori_name = $$vcf{columns}->[$i+9];
                    my $out_name = $$vcf{__col_names}->[$i];

                    $out{gtypes}{$out_name} = $$line{gtypes}{$ori_name};

                    # This is to convert 0/1 to G/C
                    my ($alleles,$seps,$is_phased,$is_empty) = $vcf->parse_haplotype($line,$ori_name);
                    if ( defined $new_ref )
                    {
                        my @als;
                        for my $al (@$alleles) 
                        { 
                            push @als, exists($ref_alt_map{$ref}{$al}) ? $ref_alt_map{$ref}{$al} : '.';
                        }
                        $out{gtypes}{$out_name}{GT} = $vcf->format_haplotype(\@als,$seps);
                    }
                    else
                    {
                        $out{gtypes}{$out_name}{GT} = $vcf->format_haplotype($alleles,$seps);
                    }
                }
                $out{REF} = defined $new_ref ? $new_ref : $ref;
            }

            $out{INFO} = { %info }; 
            $out{INFO}{SF} = join(',',@src_files);

            # Output the QUAL information
            my $qual;
            for (my $i=0; $i<@quals; $i++)
            {
                $qual += $quals[$i] * $qual_weights[$i] * (1.0 / $qual_weights_sum);
            }
            $out{QUAL} = defined $qual ? sprintf("%.2f",$qual) : $$vcf_out{defaults}{QUAL};

            # Output the FILTER information: remove PASS or missing value if some other information
            #   is present.
            delete($filters{$$vcf_out{defaults}{default}});
            if ( exists($filters{$$vcf_out{filter_passed}}) && scalar keys %filters > 1 )
            {
                delete($filters{$$vcf_out{filter_passed}});
            }
            $out{FILTER} = [ keys %filters ];
            if ( !@{$out{FILTER}} ) { push @{$out{FILTER}},$$vcf_out{defaults}{default}; }

            # The GT field must come as first
            delete($format{GT});
            $out{FORMAT} = ['GT'];
            for my $key (keys %format) { push @{$out{FORMAT}},$key; }

            if ( $have_samples )
            {
                $vcf_out->format_genotype_strings(\%out);
            }
            else
            {
                if ( defined $an ) { $out{INFO}{AN}=$an; }
                if ( scalar keys %ac ) 
                { 
                    my @acs;
                    for my $alt (@{$out{ALT}})
                    {
                        # Some of the files may not have AC, the AC count can be undefined in such a case.
                        push @acs, exists($ac{$alt}) ? $ac{$alt} : 0; 
                    }
                    $out{INFO}{AC} = join(',',@acs);
                }
            }
            print $vcf_out->format_line(\%out);
        }
    }
    for my $vcf (@vcfs) 
    { 
        $vcf->close() or error("close failed: $$vcf{file}\n"); 
    }
}


sub advance_position
{
    my ($opts,$vcfs) = @_;

    my $min_pos;
    for my $vcf (@$vcfs)
    {
        fill_buffer($opts,$vcf) unless $$vcf{done};
        if ( @{$$vcf{line_buffer}} && (!defined $min_pos or $min_pos>$$vcf{line_buffer}[0]{POS}) ) { $min_pos = $$vcf{line_buffer}[0]{POS}; }
    }
    if ( !defined $min_pos ) { return undef; }

    my ($first,$has_snp,$has_indel);
    for my $vcf (@$vcfs)
    {
        delete($$vcf{last_line});

        if ( @{$$vcf{line_buffer}} && $min_pos ne $$vcf{line_buffer}[0]{POS} ) { next; }
        if ( !defined $first ) 
        { 
            $$vcf{last_line} = shift @{$$vcf{line_buffer}};
            $first = $$vcf{last_line};
            next;
        }
        my $irec;
        for (my $i=0; $i<@{$$vcf{line_buffer}}; $i++)
        {
            my $line = $$vcf{line_buffer}[$i];
            if ( $$line{POS} ne $$first{POS} ) { last; }

            if ( $$opts{collapse_any} ) { $irec=$i; last; }  # checking position only
            if ( $$opts{collapse_snps} && $$first{variant_type}&1 && $$line{variant_type}&1 ) { $irec=$i; last; }
            if ( $$opts{collapse_indels} && $$first{variant_type}&2 && $$line{variant_type}&2 ) { $irec=$i; last; }

            if ( $$vcf{line_buffer}[$i]{REF} ne $$first{REF} ) { next; } # refs do not match
            for my $al1 (@{$$line{ALT}})
            {
                for my $al2 (@{$$first{ALT}})
                {
                    if ( $al1 eq $al2 ) { $irec=$i; last; }
                }
                if ( defined $irec ) { last; }
            }
            if ( defined $irec ) { last; }
        }
        if ( defined $irec )
        {
            $$vcf{last_line} = splice(@{$$vcf{line_buffer}},$irec,1);
        }
    }
    return $min_pos;
}

sub fill_buffer
{
    my ($opts,$vcf) = @_;
    if ( @{$$vcf{line_buffer}} && $$vcf{line_buffer}[0]{POS}!=$$vcf{line_buffer}[-1]{POS} ) { return; }
    while ( 1 )
    {
        my $line = $vcf->next_data_hash();
        if ( !$line ) { $$vcf{done} = 1; return; }
        if ( !$$opts{collapse_any} ) 
        {
            for my $al (@{$$line{ALT}})
            {
                my ($type,$len,$ht) = $vcf->event_type($$line{REF},$al);
                if ( $type eq 's' or $type eq 'r' ) { $$line{variant_type} |= 1; }
                if ( $type eq 'i' or $type eq 'o' ) { $$line{variant_type} |= 2; }
            }
        }
        push @{$$vcf{line_buffer}}, $line;
        if ( $$vcf{line_buffer}[0]{POS} != $$vcf{line_buffer}[-1]{POS} ) { return; }
    }
}


# Field joiner methods
sub joiner_sum
{
    my ($ori,$new) = @_;
    $$ori += $new;
}

sub joiner_dp4
{
    my ($ori,$new) = @_;
    my @vals1 = split(/,/,$$ori);
    my @vals2 = split(/,/,$new);
    if ( @vals1 != @vals2 ) { error("Cannot join: $$ori vs $new\n"); }
    for (my $i=0; $i<@vals1; $i++)
    {
        $vals1[$i] += $vals2[$i];
    }
    $$ori = join(',',@vals1);
}