Source: fingerprinting.go in package github.com/prometheus/common/model

Copyright 2013 The Prometheus Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.


package model

import (
	"fmt"
	"strconv"
)

Fingerprint provides a hash-capable representation of a Metric. For our purposes, FNV-1A 64-bit is used.

type Fingerprint uint64

FingerprintFromString transforms a string representation into a Fingerprint.

func FingerprintFromString(s string) (Fingerprint, error) {
	num, err := strconv.ParseUint(s, 16, 64)
	return Fingerprint(num), err
}

ParseFingerprint parses the input string into a fingerprint.

func ParseFingerprint(s string) (Fingerprint, error) {
	num, err := strconv.ParseUint(s, 16, 64)
	if err != nil {
		return 0, err
	}
	return Fingerprint(num), nil
}

func (f Fingerprint) String() string {
	return fmt.Sprintf("%016x", uint64(f))
}

Fingerprints represents a collection of Fingerprint subject to a given natural sorting scheme. It implements sort.Interface.

type Fingerprints []Fingerprint

Len implements sort.Interface.

func (f Fingerprints) Len() int {
	return len(f)
}

Less implements sort.Interface.

func (f Fingerprints) Less(i, j int) bool {
	return f[i] < f[j]
}

Swap implements sort.Interface.

func (f Fingerprints) Swap(i, j int) {
	f[i], f[j] = f[j], f[i]
}

FingerprintSet is a set of Fingerprints.

type FingerprintSet map[Fingerprint]struct{}

Equal returns true if both sets contain the same elements (and not more).

func (s FingerprintSet) Equal(o FingerprintSet) bool {
	if len(s) != len(o) {
		return false
	}

	for k := range s {
		if _, ok := o[k]; !ok {
			return false
		}
	}

	return true
}

Intersection returns the elements contained in both sets.

func (s FingerprintSet) Intersection(o FingerprintSet) FingerprintSet {
	myLength, otherLength := len(s), len(o)
	if myLength == 0 || otherLength == 0 {
		return FingerprintSet{}
	}

	subSet := s
	superSet := o

	if otherLength < myLength {
		subSet = o
		superSet = s
	}

	out := FingerprintSet{}

	for k := range subSet {
		if _, ok := superSet[k]; ok {
			out[k] = struct{}{}
		}
	}

	return out