read NCBI Blast seqdb sequence database .nin file metadata

index.js

// $ node read.js nt.00.nin
var fs = require('fs')
var int53 = require('int53')
f = process.argv[2]

function read (fd, start, end, cb) {
  var len = end - start + 1
  var buf = new Buffer(len)
  fs.read(fd, buf, 0, len, start, function (err) {
    cb(err, buf)
  })
}

fs.open(f, 'r', function (err, fd) {
  read(fd, 0, 1024, function (err, buf) {
    var offset = 8
    var titlen = buf.readUInt32BE(offset)
    offset += 4
    var title = buf.slice(offset, offset + titlen)
    offset = offset + titlen
    var datelen = buf.readUInt32BE(offset)
    offset += 4
    var date = buf.slice(offset, offset + datelen)
    offset = offset + datelen
    var oidlen = buf.readUInt32BE(offset)
    offset += 4
    var baselen = buf.slice(offset, offset + 8)
    baselen = int53.readUInt64LE(baselen)

    console.log(oidlen)
//    console.log(baselen)
  })
})