Imported Upstream version 0.1.7~dfsg

[samtools.git] / misc / sam2vcf.pl

diff --git a/misc/sam2vcf.pl b/misc/sam2vcf.pl
new file mode 100755 (executable)
index 0000000..ede7bd8
--- /dev/null
+++ b/misc/sam2vcf.pl
@@ -0,0 +1,217 @@
+#!/usr/bin/perl -w
+# 
+# VCF specs: http://www.1000genomes.org/wiki/doku.php?id=1000_genomes:analysis:vcfv3.2
+
+# Contact: pd3@sanger
+# Version: 2009-10-08
+
+use strict;
+use warnings;
+use Carp;
+
+my $opts = parse_params();
+do_pileup_to_vcf($opts);
+
+exit;
+
+#---------------
+
+sub error
+{
+    my (@msg) = @_;
+    if ( scalar @msg ) { croak(@msg); }
+    die
+        "Usage: sam2vcf.pl [OPTIONS] < in.pileup > out.vcf\n",
+        "Options:\n",
+        "   -r, -refseq <file.fa>            The reference sequence, required when indels are present.\n",
+        "   -h, -?, --help                   This help message.\n",
+        "\n";
+}
+
+
+sub parse_params
+{
+    my %opts = ();
+
+    $opts{fh_in}  = *STDIN;
+    $opts{fh_out} = *STDOUT;
+
+    while (my $arg=shift(@ARGV))
+    {
+        if ( $arg eq '-r' || $arg eq '--refseq' ) { $opts{refseq}=shift(@ARGV); next; }
+        if ( $arg eq '-?' || $arg eq '-h' || $arg eq '--help' ) { error(); }
+
+        error("Unknown parameter \"$arg\". Run -h for help.\n");
+    }
+    return \%opts;
+}
+
+sub iupac_to_gtype
+{
+    my ($ref,$base) = @_;
+    my %iupac = (
+            'K' => ['G','T'],
+            'M' => ['A','C'],
+            'S' => ['C','G'],
+            'R' => ['A','G'],
+            'W' => ['A','T'],
+            'Y' => ['C','T'],
+            );
+    if ( !exists($iupac{$base}) ) 
+    { 
+        if ( $ref eq $base ) { return ('.','0|0'); }
+        return ($base,'1|1');
+    }
+    my $gt = $iupac{$base};
+    if ( $$gt[0] eq $ref  ) { return ($$gt[1],'0|1'); }
+    elsif ( $$gt[1] eq $ref ) { return ($$gt[0],'0|1'); }
+    return ("$$gt[0],$$gt[1]",'1|2');
+}
+
+
+sub parse_indel
+{
+    my ($cons) = @_;
+    if ( $cons=~/^-/ ) 
+    { 
+        my $len = length($');
+        return "D$len"; 
+    }
+    elsif ( $cons=~/^\+/ ) { return "I$'"; }
+    elsif ( $cons eq '*' ) { return undef; }
+    error("FIXME: could not parse [$cons]\n");
+}
+
+
+# An example of the pileup format:
+#   1       3000011 C       C       32      0       98      1       ^~,     A
+#   1       3002155 *       +T/+T   53      119     52      5       +T      *       4       1       0
+#   1       3003094 *       -TT/-TT 31      164     60      11      -TT     *       5       6       0
+#   1       3073986 *       */-AAAAAAAAAAAAAA       3       3       45      9       *       -AAAAAAAAAAAAAA 7       2       0
+#
+sub do_pileup_to_vcf
+{
+    my ($opts) = @_;
+
+    my $fh_in  = $$opts{fh_in};
+    my $fh_out = $$opts{fh_out};
+    my ($prev_chr,$prev_pos,$prev_ref);
+    my $refseq;
+
+    while (my $line=<$fh_in>)
+    {
+        chomp($line);
+        my ($chr,$pos,$ref,$cons,$cons_qual,$snp_qual,$rms_qual,$depth,@items) = split(/\t/,$line);
+
+        my ($alt,$gt);
+        if ( $ref eq '*' )
+        {
+            # An indel is involved.
+            if ($chr ne $prev_chr || $pos ne $prev_pos) 
+            {
+                if ( !$$opts{refseq} ) { error("Cannot do indels without the reference.\n"); }
+                if ( !$refseq ) { $refseq = Fasta->new(file=>$$opts{refseq}); }
+                $ref = $refseq->get_base($chr,$pos);
+            }
+            else { $ref = $prev_ref; }
+
+            # One of the alleles can be a reference and it can come in arbitrary order
+            my ($al1,$al2) = split(m{/},$cons);
+            my $alt1 = parse_indel($al1);
+            my $alt2 = parse_indel($al2);
+            if ( !$alt1 && !$alt2 ) { error("FIXME: could not parse indel:\n", $line); }
+            if ( $alt1 && $alt2 && $alt1 eq $alt2 ) { $alt2=''; }
+            if ( !$alt1 ) 
+            { 
+                $alt=$alt2; 
+                $gt='0|1'; 
+            }
+            elsif ( !$alt2 ) 
+            { 
+                $alt=$alt1; 
+                $gt='0|1'; 
+            }
+            else 
+            { 
+                $alt="$alt1,$alt2"; 
+                $gt='1|2'; 
+            }
+        }
+        else
+        {
+            # SNP
+            ($alt,$gt) = iupac_to_gtype($ref,$cons);
+        }
+
+        print $fh_out "$chr\t$pos\t.\t$ref\t$alt\t$snp_qual\t0\t\tGT:GQ:DP\t$gt:$cons_qual:$depth\n";
+
+        $prev_ref = $ref;
+        $prev_pos = $pos;
+        $prev_chr = $chr;
+    }
+}
+
+
+#------------- Fasta --------------------
+#
+# Uses samtools to get a requested base from a fasta file. For efficiency, preloads
+#   a chunk to memory. The size of the cached sequence can be controlled by the 'size'
+#   parameter.
+#
+package Fasta;
+
+use strict;
+use warnings;
+use Carp;
+
+sub Fasta::new
+{
+    my ($class,@args) = @_;
+    my $self = @args ? {@args} : {};
+    if ( !$$self{file} ) { $self->throw(qq[Missing the parameter "file"\n]); }
+    $$self{chr}  = undef;
+    $$self{from} = undef;
+    $$self{to}   = undef;
+    if ( !$$self{size} ) { $$self{size}=10_000_000; }
+    bless $self, ref($class) || $class;
+    return $self;
+}
+
+sub read_chunk
+{
+    my ($self,$chr,$pos) = @_;
+    my $to = $pos + $$self{size};
+    my $cmd = "samtools faidx $$self{file} $chr:$pos-$to";
+    my @out = `$cmd`;
+    if ( $? ) { $self->throw("$cmd: $!"); }
+    my $line = shift(@out);
+    if ( !($line=~/^>$chr:(\d+)-(\d+)/) ) { $self->throw("Could not parse: $line"); }
+    $$self{chr}  = $chr;
+    $$self{from} = $1;
+    $$self{to}   = $2;
+    my $chunk = '';
+    while ($line=shift(@out))
+    {
+        chomp($line);
+        $chunk .= $line;
+    }
+    $$self{chunk} = $chunk;
+    return;
+}
+
+sub get_base
+{
+    my ($self,$chr,$pos) = @_;
+    if ( !$$self{chr} || $chr ne $$self{chr} || $pos<$$self{from} || $pos>$$self{to} )
+    {
+        $self->read_chunk($chr,$pos);
+    }
+    my $idx = $pos - $$self{from};
+    return substr($$self{chunk},$idx,1);
+}
+
+sub throw
+{
+    my ($self,@msg) = @_;
+    croak(@msg);
+}