function computeIndexChunks(buffer) {
  var BLOCK_SIZE = 65536;
  var view = new jDataView(buffer, 0, buffer.byteLength, true /* little endian */);

  var minBlockIndex = Infinity;
  var contigStartOffsets = [];
  view.getInt32();  // magic
  var n_ref = view.getInt32();
  for (var j = 0; j < n_ref; j++) {
    contigStartOffsets.push(view.tell());
    var n_bin = view.getInt32();
    for (var i = 0; i < n_bin; i++) {
      view.getUint32();  // bin ID
      var n_chunk = view.getInt32();
      view.skip(n_chunk * 16);
    }
    var n_intv = view.getInt32();
    if (n_intv) {
      var offset = VirtualOffset.fromBlob(view.getBytes(8), 0),
          coffset = offset.coffset + (offset.uoffset ? BLOCK_SIZE : 0);
      minBlockIndex = coffset ? Math.min(coffset, minBlockIndex) : BLOCK_SIZE;
      view.skip((n_intv - 1) * 8);
    }
  }
  contigStartOffsets.push(view.tell());

  // At this point, `minBlockIndex` should be non-Infinity (see #405 & #406)
  return {
    chunks: _.zip(_.initial(contigStartOffsets), _.rest(contigStartOffsets)),
    minBlockIndex
  };
}
function computeIndexChunks(buffer) {
  var BLOCK_SIZE = 65536;
  var view = new jDataView(buffer, 0, buffer.byteLength, true );

  var minBlockIndex = Infinity;
  var contigStartOffsets = [];
  view.getInt32();  
  var n_ref = view.getInt32();
  for (var j = 0; j < n_ref; j++) {
    contigStartOffsets.push(view.tell());
    var n_bin = view.getInt32();
    for (var i = 0; i < n_bin; i++) {
      view.getUint32();  
      var n_chunk = view.getInt32();
      view.skip(n_chunk * 16);
    }
    var n_intv = view.getInt32();
    if (n_intv) {
      var offset = VirtualOffset.fromBlob(view.getBytes(8), 0),
          coffset = offset.coffset + (offset.uoffset ? BLOCK_SIZE : 0);
      minBlockIndex = coffset ? Math.min(coffset, minBlockIndex) : BLOCK_SIZE;
      view.skip((n_intv - 1) * 8);
    }
  }
  contigStartOffsets.push(view.tell());

  
  return {
    chunks: _.zip(_.initial(contigStartOffsets), _.rest(contigStartOffsets)),
    minBlockIndex
  };
}
function computeIndexChunks ( buffer ) { var BLOCK_SIZE = 65536 ; var view = new jDataView ( buffer , 0 , buffer . byteLength , true /* little endian */ ) ; var minBlockIndex = Infinity ; var contigStartOffsets = [ ] ; view . getInt32 ( ) ; // magic var n_ref = view . getInt32 ( ) ; for ( var j = 0 ; j < n_ref ; j ++ ) { contigStartOffsets . push ( view . tell ( ) ) ; var n_bin = view . getInt32 ( ) ; for ( var i = 0 ; i < n_bin ; i ++ ) { view . getUint32 ( ) ; // bin ID var n_chunk = view . getInt32 ( ) ; view . skip ( n_chunk * 16 ) ; } var n_intv = view . getInt32 ( ) ; if ( n_intv ) { var offset = VirtualOffset . fromBlob ( view . getBytes ( 8 ) , 0 ) , coffset = offset . coffset + ( offset . uoffset ? BLOCK_SIZE : 0 ) ; minBlockIndex = coffset ? Math . min ( coffset , minBlockIndex ) : BLOCK_SIZE ; view . skip ( ( n_intv - 1 ) * 8 ) ; } } contigStartOffsets . push ( view . tell ( ) ) ; // At this point, `minBlockIndex` should be non-Infinity (see #405 & #406) return { chunks : _ . zip ( _ . initial ( contigStartOffsets ) , _ . rest ( contigStartOffsets ) ) , minBlockIndex } ; }
In the event that index chunks aren't available from an external source, it winds up saving time to do a fast pass over the data to compute them. This allows us to parse a single contig at a time using jBinary.
In the event that index chunks aren t available from an external source it winds up saving time to do a fast pass over the data to compute them . This allows us to parse a single contig at a time using jBinary .