78 lines
1.5 KiB
Go
78 lines
1.5 KiB
Go
package chunks
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import (
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"encoding/binary"
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"math"
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"github.com/prometheus/common/model"
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)
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// XORChunk holds XOR encoded sample data.
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type XORChunk struct {
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rawChunk
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}
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// NewXORChunk returns a new chunk with XOR encoding of the given size.
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func NewXORChunk(sz int) *XORChunk {
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return &XORChunk{rawChunk: newRawChunk(sz, EncXOR)}
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}
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// Appender implements the Chunk interface.
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func (c *XORChunk) Appender() Appender {
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return &xorAppender{c: &c.rawChunk}
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}
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// Iterator implements the Chunk interface.
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func (c *XORChunk) Iterator() Iterator {
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return &xorIterator{d: c.d[1:c.l]}
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}
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type xorAppender struct {
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c *rawChunk
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num int
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buf [16]byte
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lastV float64
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lastT int64
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lastTDelta uint64
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}
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func (a *xorAppender) Append(ts model.Time, v model.SampleValue) error {
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if a.num == 0 {
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n := binary.PutVarint(a.buf[:], int64(ts))
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binary.BigEndian.PutUint64(a.buf[n:], math.Float64bits(float64(v)))
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if err := a.c.append(a.buf[:n+8]); err != nil {
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return err
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}
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a.lastT, a.lastV = int64(ts), float64(v)
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a.num++
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return nil
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}
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if a.num == 1 {
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a.lastTDelta = uint64(int64(ts) - a.lastT)
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}
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a.num++
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return nil
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}
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type xorIterator struct {
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d []byte
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}
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func (it *xorIterator) First() (model.SamplePair, bool) {
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return model.SamplePair{}, false
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}
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func (it *xorIterator) Seek(ts model.Time) (model.SamplePair, bool) {
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return model.SamplePair{}, false
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}
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func (it *xorIterator) Next() (model.SamplePair, bool) {
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return model.SamplePair{}, false
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}
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func (it *xorIterator) Err() error {
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return nil
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}
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