Encode a (timestamp_ms, value) sample.
(&mut self, timestamp_ms: i64, value: f64)
| 56 | |
| 57 | /// Encode a (timestamp_ms, value) sample. |
| 58 | pub fn encode(&mut self, timestamp_ms: i64, value: f64) { |
| 59 | let value_bits = value.to_bits(); |
| 60 | |
| 61 | if self.count == 0 { |
| 62 | self.buf.write_bits(timestamp_ms as u64, 64); |
| 63 | self.buf.write_bits(value_bits, 64); |
| 64 | self.prev_ts = timestamp_ms; |
| 65 | self.prev_value = value_bits; |
| 66 | self.count = 1; |
| 67 | return; |
| 68 | } |
| 69 | |
| 70 | // Timestamp: delta-of-delta. |
| 71 | let delta = timestamp_ms - self.prev_ts; |
| 72 | let dod = delta - self.prev_delta; |
| 73 | self.encode_timestamp_dod(dod); |
| 74 | self.prev_ts = timestamp_ms; |
| 75 | self.prev_delta = delta; |
| 76 | |
| 77 | // Value: XOR. |
| 78 | let xor = self.prev_value ^ value_bits; |
| 79 | self.encode_value_xor(xor); |
| 80 | self.prev_value = value_bits; |
| 81 | |
| 82 | self.count += 1; |
| 83 | } |
| 84 | |
| 85 | fn encode_timestamp_dod(&mut self, dod: i64) { |
| 86 | if dod == 0 { |