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author | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
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committer | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
commit | a031b83a09a8628435317a03f199cdc18b78262f (patch) | |
tree | bc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/github.com/prometheus/common/model/signature.go | |
parent | 2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff) | |
download | podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.gz podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.bz2 podman-a031b83a09a8628435317a03f199cdc18b78262f.zip |
Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/github.com/prometheus/common/model/signature.go')
-rw-r--r-- | vendor/github.com/prometheus/common/model/signature.go | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/common/model/signature.go b/vendor/github.com/prometheus/common/model/signature.go new file mode 100644 index 000000000..8762b13c6 --- /dev/null +++ b/vendor/github.com/prometheus/common/model/signature.go @@ -0,0 +1,144 @@ +// Copyright 2014 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 ( + "sort" +) + +// SeparatorByte is a byte that cannot occur in valid UTF-8 sequences and is +// used to separate label names, label values, and other strings from each other +// when calculating their combined hash value (aka signature aka fingerprint). +const SeparatorByte byte = 255 + +var ( + // cache the signature of an empty label set. + emptyLabelSignature = hashNew() +) + +// LabelsToSignature returns a quasi-unique signature (i.e., fingerprint) for a +// given label set. (Collisions are possible but unlikely if the number of label +// sets the function is applied to is small.) +func LabelsToSignature(labels map[string]string) uint64 { + if len(labels) == 0 { + return emptyLabelSignature + } + + labelNames := make([]string, 0, len(labels)) + for labelName := range labels { + labelNames = append(labelNames, labelName) + } + sort.Strings(labelNames) + + sum := hashNew() + for _, labelName := range labelNames { + sum = hashAdd(sum, labelName) + sum = hashAddByte(sum, SeparatorByte) + sum = hashAdd(sum, labels[labelName]) + sum = hashAddByte(sum, SeparatorByte) + } + return sum +} + +// labelSetToFingerprint works exactly as LabelsToSignature but takes a LabelSet as +// parameter (rather than a label map) and returns a Fingerprint. +func labelSetToFingerprint(ls LabelSet) Fingerprint { + if len(ls) == 0 { + return Fingerprint(emptyLabelSignature) + } + + labelNames := make(LabelNames, 0, len(ls)) + for labelName := range ls { + labelNames = append(labelNames, labelName) + } + sort.Sort(labelNames) + + sum := hashNew() + for _, labelName := range labelNames { + sum = hashAdd(sum, string(labelName)) + sum = hashAddByte(sum, SeparatorByte) + sum = hashAdd(sum, string(ls[labelName])) + sum = hashAddByte(sum, SeparatorByte) + } + return Fingerprint(sum) +} + +// labelSetToFastFingerprint works similar to labelSetToFingerprint but uses a +// faster and less allocation-heavy hash function, which is more susceptible to +// create hash collisions. Therefore, collision detection should be applied. +func labelSetToFastFingerprint(ls LabelSet) Fingerprint { + if len(ls) == 0 { + return Fingerprint(emptyLabelSignature) + } + + var result uint64 + for labelName, labelValue := range ls { + sum := hashNew() + sum = hashAdd(sum, string(labelName)) + sum = hashAddByte(sum, SeparatorByte) + sum = hashAdd(sum, string(labelValue)) + result ^= sum + } + return Fingerprint(result) +} + +// SignatureForLabels works like LabelsToSignature but takes a Metric as +// parameter (rather than a label map) and only includes the labels with the +// specified LabelNames into the signature calculation. The labels passed in +// will be sorted by this function. +func SignatureForLabels(m Metric, labels ...LabelName) uint64 { + if len(labels) == 0 { + return emptyLabelSignature + } + + sort.Sort(LabelNames(labels)) + + sum := hashNew() + for _, label := range labels { + sum = hashAdd(sum, string(label)) + sum = hashAddByte(sum, SeparatorByte) + sum = hashAdd(sum, string(m[label])) + sum = hashAddByte(sum, SeparatorByte) + } + return sum +} + +// SignatureWithoutLabels works like LabelsToSignature but takes a Metric as +// parameter (rather than a label map) and excludes the labels with any of the +// specified LabelNames from the signature calculation. +func SignatureWithoutLabels(m Metric, labels map[LabelName]struct{}) uint64 { + if len(m) == 0 { + return emptyLabelSignature + } + + labelNames := make(LabelNames, 0, len(m)) + for labelName := range m { + if _, exclude := labels[labelName]; !exclude { + labelNames = append(labelNames, labelName) + } + } + if len(labelNames) == 0 { + return emptyLabelSignature + } + sort.Sort(labelNames) + + sum := hashNew() + for _, labelName := range labelNames { + sum = hashAdd(sum, string(labelName)) + sum = hashAddByte(sum, SeparatorByte) + sum = hashAdd(sum, string(m[labelName])) + sum = hashAddByte(sum, SeparatorByte) + } + return sum +} |