Buffer header = new Buffer(512);
mappedFileFactory.getMemoryMappedFile().read(0, header);
DataByteArrayInputStream his = new DataByteArrayInputStream(header);
Buffer magic = new Buffer(HAWT_DB_PAGE_FILE_MAGIC.length());
his.readFully(magic.data, magic.offset, magic.length());
if( !magic.ascii().equals(HAWT_DB_PAGE_FILE_MAGIC)) {
throw new IOPagingException("File's magic does not match expected value");
}
freePageExtent = his.readInt();
headerSize = his.readInt();