mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-11-21 14:44:00 +00:00
d962568e93
This will simplify examining the returned errors such as httpserver.ErrorWithStatusCode . See https://blog.golang.org/go1.13-errors for details.
83 lines
2.3 KiB
Go
83 lines
2.3 KiB
Go
package encoding
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
|
|
)
|
|
|
|
// marshalInt64NearestDelta2 encodes src using `nearest delta2` encoding
|
|
// with the given precisionBits and appends the encoded value to dst.
|
|
//
|
|
// precisionBits must be in the range [1...64], where 1 means 50% precision,
|
|
// while 64 means 100% precision, i.e. lossless encoding.
|
|
func marshalInt64NearestDelta2(dst []byte, src []int64, precisionBits uint8) (result []byte, firstValue int64) {
|
|
if len(src) < 2 {
|
|
logger.Panicf("BUG: src must contain at least 2 items; got %d items", len(src))
|
|
}
|
|
if err := CheckPrecisionBits(precisionBits); err != nil {
|
|
logger.Panicf("BUG: %s", err)
|
|
}
|
|
|
|
firstValue = src[0]
|
|
d1 := src[1] - src[0]
|
|
dst = MarshalVarInt64(dst, d1)
|
|
v := src[1]
|
|
src = src[2:]
|
|
is := GetInt64s(len(src))
|
|
if precisionBits == 64 {
|
|
// Fast path.
|
|
for i, next := range src {
|
|
d2 := next - v - d1
|
|
d1 += d2
|
|
v += d1
|
|
is.A[i] = d2
|
|
}
|
|
} else {
|
|
// Slower path.
|
|
trailingZeros := getTrailingZeros(v, precisionBits)
|
|
for i, next := range src {
|
|
d2, tzs := nearestDelta(next-v, d1, precisionBits, trailingZeros)
|
|
trailingZeros = tzs
|
|
d1 += d2
|
|
v += d1
|
|
is.A[i] = d2
|
|
}
|
|
}
|
|
dst = MarshalVarInt64s(dst, is.A)
|
|
PutInt64s(is)
|
|
return dst, firstValue
|
|
}
|
|
|
|
// unmarshalInt64NearestDelta2 decodes src using `nearest delta2` encoding,
|
|
// appends the result to dst and returns the appended result.
|
|
//
|
|
// firstValue must be the value returned from marshalInt64NearestDelta2.
|
|
func unmarshalInt64NearestDelta2(dst []int64, src []byte, firstValue int64, itemsCount int) ([]int64, error) {
|
|
if itemsCount < 2 {
|
|
logger.Panicf("BUG: itemsCount must be greater than 1; got %d", itemsCount)
|
|
}
|
|
|
|
is := GetInt64s(itemsCount - 1)
|
|
defer PutInt64s(is)
|
|
|
|
tail, err := UnmarshalVarInt64s(is.A, src)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("cannot unmarshal nearest delta from %d bytes; src=%X: %w", len(src), src, err)
|
|
}
|
|
if len(tail) > 0 {
|
|
return nil, fmt.Errorf("unexpected tail left after unmarshaling %d items from %d bytes; tail size=%d; src=%X; tail=%X", itemsCount, len(src), len(tail), src, tail)
|
|
}
|
|
|
|
v := firstValue
|
|
d1 := is.A[0]
|
|
dst = append(dst, v)
|
|
v += d1
|
|
dst = append(dst, v)
|
|
for _, d2 := range is.A[1:] {
|
|
d1 += d2
|
|
v += d1
|
|
dst = append(dst, v)
|
|
}
|
|
return dst, nil
|
|
}
|