common_query/
prometheus.rs

1// Copyright 2023 Greptime Team
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15/// Canonical Prometheus stale-marker NaN bit pattern.
16pub const PROMETHEUS_STALE_NAN_BITS: u64 = 0x7ff0_0000_0000_0002;
17
18/// Returns whether `value` is the canonical Prometheus stale-marker NaN.
19#[inline]
20pub fn is_prometheus_stale_nan(value: f64) -> bool {
21    value.to_bits() == PROMETHEUS_STALE_NAN_BITS
22}
23
24#[cfg(test)]
25mod tests {
26    use super::*;
27
28    #[test]
29    fn recognizes_only_the_canonical_stale_marker() {
30        assert!(is_prometheus_stale_nan(f64::from_bits(
31            0x7ff0_0000_0000_0002
32        )));
33        assert!(!is_prometheus_stale_nan(f64::from_bits(
34            0x7ff8_0000_0000_0000
35        )));
36    }
37}
common_query/prometheus.rs

common_query/
prometheus.rs
