Bio::SeqIO strider
SummaryIncluded librariesPackage variablesSynopsisDescriptionGeneral documentationMethods
Bio::SeqIO::strider - DNA strider sequence input/output stream
Package variables
Privates (from "my" definitions)
%type2alphabet = reverse %alphabet2type
$size_F_HEADER = 112
%alphabet2type = ( dna => 1, rna => 3, protein => 4, )
$c = new Convert::Binary::C ( ByteOrder => 'BigEndian', Alignment => 2 )
Included modules
Do not use this module directly. Use it via the Bio::SeqIO class.
This object can transform Bio::Seq objects to and from strider
'binary' format, as documented in the strider manual, in which the
first 112 bytes are a header, following by the sequence, followed by a
sequence description.
Note: it does NOT assign any sequence identifier, since they are not
contained in the byte stream of the file; the Strider application
simply displays the name of the file on disk as the name of the
sequence. The caller should set the id, probably based on the name of
the file (after possibly cleaning up whitespace, which ought not to be
used as the id in most applications).
Note: the strider 'comment' is mapped to the BioPerl 'description'
(since there is no other text field, and description maps to defline
No description
Methods description
next_seqcode    nextTop
 Title   : next_seq
Usage : $seq = $stream->next_seq()
Function: returns the next sequence in the stream
Returns : Bio::Seq object
Args : NONE
 Title   : write_seq
Usage : $stream->write_seq(@seq)
Function: writes the $seq object into the stream
Returns : 1 for success and 0 for error
Args : array of 1 to n Bio::PrimarySeqI objects
Methods code
sub _initialize {
  my($self,@args) = @_;
  unless ( defined $self->sequence_factory ) {
    $self->sequence_factory(Bio::Seq::SeqFactory->new(-verbose => $self->verbose(), 
						      -type => 'Bio::Seq::RichSeq'));
sub next_seq {
  my( $self ) = @_;
  my $fh =  $self->_fh;
  my ($header,$sequence,$fulldesc);
  eval {read $fh,$header,$size_F_HEADER};
  $self->throw ("$@  while attempting to reading strider header from " . $self->{'_file'}) if $@; 
  $self->throw("required $size_F_HEADER bytes while reading strider header in " . $self->{'_file'} . " but found: " . length($header))  
    unless $size_F_HEADER == length($header);
  my $headerdata = $c->unpack('F_HEADER',$header) or return;
  read $fh,$sequence,$headerdata->{nLength};
  read $fh,$fulldesc,$headerdata->{com_length};
  $fulldesc =~ s/\cM/ /g;	# gratuitous replacement of mac
# linefeed with space.
my $seq = $self->sequence_factory->create( # -id => $main::ARGV, #might want to set this in caller to $ARGV.
-seq => $sequence, -desc => $fulldesc, -alphabet => $type2alphabet{$headerdata->{type}} || 'dna', ); return $seq;
sub write_seq {
  my ($self,@seq) = @_;
  my $fh =  $self->_fh() || *STDOUT; #die "could not determine filehandle in";
foreach my $seq (@seq) { $self->throw("Did not provide a valid Bio::PrimarySeqI object") unless defined $seq && ref($seq) && $seq->isa('Bio::PrimarySeqI'); my $headerdata = $c->pack('F_HEADER',{ versionNb => 0, type => $alphabet2type{$seq->alphabet} || $alphabet2type{dna}, topology => $seq->is_circular ? 1 : 0, nLength => $seq->length, nMinus => 0, com_length => length($seq->desc || ""), }); print $fh $headerdata, $seq->seq() || "" , $seq->desc || ""; } } 1; __DATA__ //The following was taken from the strider 1.4 release notes Appendix (with //some comments gleaned from other parts of manual) struct F_HEADER { char versionNb; // the format version number, currently it is set to 0 char type; // 1=DNA, 2=DNA Degenerate, 3=RNA or 4=Protein char topology; // linear or circular - 0 for a linear sequence, 1 for a circular one char reserved1; int reserved2; int reserved3; int reserved4; char reserved5; char filler1; short filler2; int filler3; int reserved6; int nLength; // Sequence length - the length the Sequence field (the number of char in the text, each being a base or an aa) int nMinus; // nb of "negative" bases, i.e. the number of bases numbered with negative numbers int reserved7; int reserved8; int reserved9; int reserved10; int reserved11; char reserved12[32]; short reserved13; short filler4; char reserved14; char reserved15; char reserved16; char filler5; int com_length; // the length the Comment field (the number of char in the text). int reserved17; int filler6; int filler7; };
General documentation
Mailing ListsTop
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Support Top
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rather than to the module maintainer directly. Many experienced and
reponsive experts will be able look at the problem and quickly
address it. Please include a thorough description of the problem
with code and data examples if at all possible.
Reporting BugsTop
Report bugs to the Bioperl bug tracking system to help us keep track
the bugs and their resolution. Bug reports can be submitted via the
AUTHORS - Malcolm CookTop
Modelled after Bio::SeqIO::fasta by Ewan Birney <> and
Lincoln Stein <>
The rest of the documentation details each of the object
methods. Internal methods are usually preceded with a _