// NewRW function reads or creates a block on given directory.
// It will automatically load all existing block files.
func NewRW(dir string, rsz int64) (b *RWBlock, err error) {
rbs := rsz * pointsz
sfp := path.Join(dir, prefix)
sfs := segsz - (segsz % rbs)
ssz := sfs / rbs
m, err := segmmap.New(sfp, sfs, false)
if err != nil {
return nil, err
}
b = &RWBlock{
records: [][]protocol.Point{},
recsMtx: new(sync.RWMutex),
segments: m,
recLength: rsz,
recBytes: rbs,
segRecs: ssz,
emptyRec: make([]protocol.Point, rsz),
}
// This will use the segment.Read method until it reaches the EOF
// Make sure no other operation uses segment.Read/Write methods.
// If it becomes necessary, save the offset value in this struct.
if err := b.readRecords(); err != nil {
return nil, err
}
return b, nil
}
// NewLogs creates a log type index persister.
func NewLogs(dir string) (l *Logs, err error) {
sfpath := path.Join(dir, prefixlogs)
f, err := segmmap.New(sfpath, segszlogs, false)
if err != nil {
return nil, err
}
l = &Logs{
logFile: f,
nextID: 0,
nextOff: 0,
iomutex: &sync.Mutex{},
}
return l, nil
}