// read reads the current key and value from the current block.
func (c *cursor) read() (key int64, value interface{}) {
// Return nil if the offset is at the end of the buffer.
if c.off >= len(c.buf) {
return -1, nil
}
// Otherwise read the current entry.
buf := c.buf[c.off:]
dataSize := entryDataSize(buf)
return tsdb.DecodeKeyValue(c.field, c.dec, buf[0:8], buf[entryHeaderSize:entryHeaderSize+dataSize])
}
// Next returns the next key/value pair from the cursor.
func (c *cursor) Next() (key int64, value interface{}) {
for {
k, v := func() (int64, interface{}) {
if c.keyBuf != -2 {
k, v := c.keyBuf, c.valBuf
c.keyBuf = -2
return k, v
}
k, v := c.cursor.Next()
if k == nil {
return -1, nil
}
return tsdb.DecodeKeyValue(c.field, c.dec, k, v)
}()
if k != -1 && v == nil {
// There is a point in the series at the next timestamp,
// but not for this cursor's field. Go to the next point.
continue
}
return k, v
}
}
// Seek moves the cursor to a position.
func (c *cursor) SeekTo(seek int64) {
var seekBytes [8]byte
binary.BigEndian.PutUint64(seekBytes[:], uint64(seek))
k, v := c.cursor.Seek(seekBytes[:])
c.keyBuf, c.valBuf = tsdb.DecodeKeyValue(c.field, c.dec, k, v)
}