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70 lines
1.5 KiB
70 lines
1.5 KiB
// Copyright 2019 The Prometheus Authors |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// http://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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package index |
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import ( |
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"math" |
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"sort" |
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) |
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// Stat holds values for a single cardinality statistic. |
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type Stat struct { |
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Name string |
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Count uint64 |
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} |
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type maxHeap struct { |
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maxLength int |
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minValue uint64 |
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minIndex int |
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Items []Stat |
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} |
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func (m *maxHeap) init(len int) { |
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m.maxLength = len |
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m.minValue = math.MaxUint64 |
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m.Items = make([]Stat, 0, len) |
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} |
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func (m *maxHeap) push(item Stat) { |
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if len(m.Items) < m.maxLength { |
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if item.Count < m.minValue { |
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m.minValue = item.Count |
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m.minIndex = len(m.Items) |
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} |
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m.Items = append(m.Items, item) |
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return |
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} |
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if item.Count < m.minValue { |
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return |
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} |
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m.Items[m.minIndex] = item |
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m.minValue = item.Count |
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for i, stat := range m.Items { |
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if stat.Count < m.minValue { |
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m.minValue = stat.Count |
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m.minIndex = i |
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} |
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} |
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} |
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func (m *maxHeap) get() []Stat { |
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sort.Slice(m.Items, func(i, j int) bool { |
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return m.Items[i].Count > m.Items[j].Count |
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}) |
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return m.Items |
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}
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