83 lines
2.3 KiB
Go
83 lines
2.3 KiB
Go
// Copyright 2021 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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// The code in this file was largely written by Damian Gryski as part of
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// https://github.com/dgryski/go-tsz and published under the license below.
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// It was modified to accommodate reading from byte slices without modifying
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// the underlying bytes, which would panic when reading from mmap'd
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// read-only byte slices.
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package chunkenc
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import "github.com/prometheus/prometheus/pkg/histogram"
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func writeHistoChunkMeta(b *bstream, schema int32, posSpans, negSpans []histogram.Span) {
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putInt64VBBucket(b, int64(schema))
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putHistoChunkMetaSpans(b, posSpans)
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putHistoChunkMetaSpans(b, negSpans)
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}
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func putHistoChunkMetaSpans(b *bstream, spans []histogram.Span) {
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putInt64VBBucket(b, int64(len(spans)))
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for _, s := range spans {
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putInt64VBBucket(b, int64(s.Length))
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putInt64VBBucket(b, int64(s.Offset))
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}
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}
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func readHistoChunkMeta(b *bstreamReader) (int32, []histogram.Span, []histogram.Span, error) {
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v, err := readInt64VBBucket(b)
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if err != nil {
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return 0, nil, nil, err
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}
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schema := int32(v)
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posSpans, err := readHistoChunkMetaSpans(b)
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if err != nil {
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return 0, nil, nil, err
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}
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negSpans, err := readHistoChunkMetaSpans(b)
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if err != nil {
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return 0, nil, nil, err
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}
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return schema, posSpans, negSpans, nil
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}
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func readHistoChunkMetaSpans(b *bstreamReader) ([]histogram.Span, error) {
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var spans []histogram.Span
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num, err := readInt64VBBucket(b)
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if err != nil {
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return nil, err
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}
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for i := 0; i < int(num); i++ {
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length, err := readInt64VBBucket(b)
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if err != nil {
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return nil, err
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}
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offset, err := readInt64VBBucket(b)
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if err != nil {
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return nil, err
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}
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spans = append(spans, histogram.Span{
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Length: uint32(length),
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Offset: int32(offset),
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})
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}
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return spans, nil
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}
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