mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-22 00:16:23 +01:00
2b55d167d7
The standard Snappy encoder from github.com/golang/snappy shows quite good performance number for compressing the Prometheus remote_write proto messages according to the added benchmarks, so there is no need in switching to github.com/klauspost/compress/s2 yet.
308 lines
7.6 KiB
Go
308 lines
7.6 KiB
Go
//go:build !amd64 || appengine || !gc || noasm
|
|
// +build !amd64 appengine !gc noasm
|
|
|
|
package s2
|
|
|
|
import (
|
|
"math/bits"
|
|
)
|
|
|
|
// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
|
|
// assumes that the varint-encoded length of the decompressed bytes has already
|
|
// been written.
|
|
//
|
|
// It also assumes that:
|
|
// len(dst) >= MaxEncodedLen(len(src))
|
|
func encodeBlock(dst, src []byte) (d int) {
|
|
if len(src) < minNonLiteralBlockSize {
|
|
return 0
|
|
}
|
|
return encodeBlockGo(dst, src)
|
|
}
|
|
|
|
// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
|
|
// assumes that the varint-encoded length of the decompressed bytes has already
|
|
// been written.
|
|
//
|
|
// It also assumes that:
|
|
// len(dst) >= MaxEncodedLen(len(src))
|
|
func encodeBlockBetter(dst, src []byte) (d int) {
|
|
return encodeBlockBetterGo(dst, src)
|
|
}
|
|
|
|
// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
|
|
// assumes that the varint-encoded length of the decompressed bytes has already
|
|
// been written.
|
|
//
|
|
// It also assumes that:
|
|
// len(dst) >= MaxEncodedLen(len(src))
|
|
func encodeBlockBetterSnappy(dst, src []byte) (d int) {
|
|
return encodeBlockBetterSnappyGo(dst, src)
|
|
}
|
|
|
|
// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
|
|
// assumes that the varint-encoded length of the decompressed bytes has already
|
|
// been written.
|
|
//
|
|
// It also assumes that:
|
|
// len(dst) >= MaxEncodedLen(len(src))
|
|
func encodeBlockSnappy(dst, src []byte) (d int) {
|
|
if len(src) < minNonLiteralBlockSize {
|
|
return 0
|
|
}
|
|
return encodeBlockSnappyGo(dst, src)
|
|
}
|
|
|
|
// emitLiteral writes a literal chunk and returns the number of bytes written.
|
|
//
|
|
// It assumes that:
|
|
// dst is long enough to hold the encoded bytes
|
|
// 0 <= len(lit) && len(lit) <= math.MaxUint32
|
|
func emitLiteral(dst, lit []byte) int {
|
|
if len(lit) == 0 {
|
|
return 0
|
|
}
|
|
const num = 63<<2 | tagLiteral
|
|
i, n := 0, uint(len(lit)-1)
|
|
switch {
|
|
case n < 60:
|
|
dst[0] = uint8(n)<<2 | tagLiteral
|
|
i = 1
|
|
case n < 1<<8:
|
|
dst[1] = uint8(n)
|
|
dst[0] = 60<<2 | tagLiteral
|
|
i = 2
|
|
case n < 1<<16:
|
|
dst[2] = uint8(n >> 8)
|
|
dst[1] = uint8(n)
|
|
dst[0] = 61<<2 | tagLiteral
|
|
i = 3
|
|
case n < 1<<24:
|
|
dst[3] = uint8(n >> 16)
|
|
dst[2] = uint8(n >> 8)
|
|
dst[1] = uint8(n)
|
|
dst[0] = 62<<2 | tagLiteral
|
|
i = 4
|
|
default:
|
|
dst[4] = uint8(n >> 24)
|
|
dst[3] = uint8(n >> 16)
|
|
dst[2] = uint8(n >> 8)
|
|
dst[1] = uint8(n)
|
|
dst[0] = 63<<2 | tagLiteral
|
|
i = 5
|
|
}
|
|
return i + copy(dst[i:], lit)
|
|
}
|
|
|
|
// emitRepeat writes a repeat chunk and returns the number of bytes written.
|
|
// Length must be at least 4 and < 1<<24
|
|
func emitRepeat(dst []byte, offset, length int) int {
|
|
// Repeat offset, make length cheaper
|
|
length -= 4
|
|
if length <= 4 {
|
|
dst[0] = uint8(length)<<2 | tagCopy1
|
|
dst[1] = 0
|
|
return 2
|
|
}
|
|
if length < 8 && offset < 2048 {
|
|
// Encode WITH offset
|
|
dst[1] = uint8(offset)
|
|
dst[0] = uint8(offset>>8)<<5 | uint8(length)<<2 | tagCopy1
|
|
return 2
|
|
}
|
|
if length < (1<<8)+4 {
|
|
length -= 4
|
|
dst[2] = uint8(length)
|
|
dst[1] = 0
|
|
dst[0] = 5<<2 | tagCopy1
|
|
return 3
|
|
}
|
|
if length < (1<<16)+(1<<8) {
|
|
length -= 1 << 8
|
|
dst[3] = uint8(length >> 8)
|
|
dst[2] = uint8(length >> 0)
|
|
dst[1] = 0
|
|
dst[0] = 6<<2 | tagCopy1
|
|
return 4
|
|
}
|
|
const maxRepeat = (1 << 24) - 1
|
|
length -= 1 << 16
|
|
left := 0
|
|
if length > maxRepeat {
|
|
left = length - maxRepeat + 4
|
|
length = maxRepeat - 4
|
|
}
|
|
dst[4] = uint8(length >> 16)
|
|
dst[3] = uint8(length >> 8)
|
|
dst[2] = uint8(length >> 0)
|
|
dst[1] = 0
|
|
dst[0] = 7<<2 | tagCopy1
|
|
if left > 0 {
|
|
return 5 + emitRepeat(dst[5:], offset, left)
|
|
}
|
|
return 5
|
|
}
|
|
|
|
// emitCopy writes a copy chunk and returns the number of bytes written.
|
|
//
|
|
// It assumes that:
|
|
// dst is long enough to hold the encoded bytes
|
|
// 1 <= offset && offset <= math.MaxUint32
|
|
// 4 <= length && length <= 1 << 24
|
|
func emitCopy(dst []byte, offset, length int) int {
|
|
if offset >= 65536 {
|
|
i := 0
|
|
if length > 64 {
|
|
// Emit a length 64 copy, encoded as 5 bytes.
|
|
dst[4] = uint8(offset >> 24)
|
|
dst[3] = uint8(offset >> 16)
|
|
dst[2] = uint8(offset >> 8)
|
|
dst[1] = uint8(offset)
|
|
dst[0] = 63<<2 | tagCopy4
|
|
length -= 64
|
|
if length >= 4 {
|
|
// Emit remaining as repeats
|
|
return 5 + emitRepeat(dst[5:], offset, length)
|
|
}
|
|
i = 5
|
|
}
|
|
if length == 0 {
|
|
return i
|
|
}
|
|
// Emit a copy, offset encoded as 4 bytes.
|
|
dst[i+0] = uint8(length-1)<<2 | tagCopy4
|
|
dst[i+1] = uint8(offset)
|
|
dst[i+2] = uint8(offset >> 8)
|
|
dst[i+3] = uint8(offset >> 16)
|
|
dst[i+4] = uint8(offset >> 24)
|
|
return i + 5
|
|
}
|
|
|
|
// Offset no more than 2 bytes.
|
|
if length > 64 {
|
|
off := 3
|
|
if offset < 2048 {
|
|
// emit 8 bytes as tagCopy1, rest as repeats.
|
|
dst[1] = uint8(offset)
|
|
dst[0] = uint8(offset>>8)<<5 | uint8(8-4)<<2 | tagCopy1
|
|
length -= 8
|
|
off = 2
|
|
} else {
|
|
// Emit a length 60 copy, encoded as 3 bytes.
|
|
// Emit remaining as repeat value (minimum 4 bytes).
|
|
dst[2] = uint8(offset >> 8)
|
|
dst[1] = uint8(offset)
|
|
dst[0] = 59<<2 | tagCopy2
|
|
length -= 60
|
|
}
|
|
// Emit remaining as repeats, at least 4 bytes remain.
|
|
return off + emitRepeat(dst[off:], offset, length)
|
|
}
|
|
if length >= 12 || offset >= 2048 {
|
|
// Emit the remaining copy, encoded as 3 bytes.
|
|
dst[2] = uint8(offset >> 8)
|
|
dst[1] = uint8(offset)
|
|
dst[0] = uint8(length-1)<<2 | tagCopy2
|
|
return 3
|
|
}
|
|
// Emit the remaining copy, encoded as 2 bytes.
|
|
dst[1] = uint8(offset)
|
|
dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
|
|
return 2
|
|
}
|
|
|
|
// emitCopyNoRepeat writes a copy chunk and returns the number of bytes written.
|
|
//
|
|
// It assumes that:
|
|
// dst is long enough to hold the encoded bytes
|
|
// 1 <= offset && offset <= math.MaxUint32
|
|
// 4 <= length && length <= 1 << 24
|
|
func emitCopyNoRepeat(dst []byte, offset, length int) int {
|
|
if offset >= 65536 {
|
|
i := 0
|
|
if length > 64 {
|
|
// Emit a length 64 copy, encoded as 5 bytes.
|
|
dst[4] = uint8(offset >> 24)
|
|
dst[3] = uint8(offset >> 16)
|
|
dst[2] = uint8(offset >> 8)
|
|
dst[1] = uint8(offset)
|
|
dst[0] = 63<<2 | tagCopy4
|
|
length -= 64
|
|
if length >= 4 {
|
|
// Emit remaining as repeats
|
|
return 5 + emitCopyNoRepeat(dst[5:], offset, length)
|
|
}
|
|
i = 5
|
|
}
|
|
if length == 0 {
|
|
return i
|
|
}
|
|
// Emit a copy, offset encoded as 4 bytes.
|
|
dst[i+0] = uint8(length-1)<<2 | tagCopy4
|
|
dst[i+1] = uint8(offset)
|
|
dst[i+2] = uint8(offset >> 8)
|
|
dst[i+3] = uint8(offset >> 16)
|
|
dst[i+4] = uint8(offset >> 24)
|
|
return i + 5
|
|
}
|
|
|
|
// Offset no more than 2 bytes.
|
|
if length > 64 {
|
|
// Emit a length 60 copy, encoded as 3 bytes.
|
|
// Emit remaining as repeat value (minimum 4 bytes).
|
|
dst[2] = uint8(offset >> 8)
|
|
dst[1] = uint8(offset)
|
|
dst[0] = 59<<2 | tagCopy2
|
|
length -= 60
|
|
// Emit remaining as repeats, at least 4 bytes remain.
|
|
return 3 + emitCopyNoRepeat(dst[3:], offset, length)
|
|
}
|
|
if length >= 12 || offset >= 2048 {
|
|
// Emit the remaining copy, encoded as 3 bytes.
|
|
dst[2] = uint8(offset >> 8)
|
|
dst[1] = uint8(offset)
|
|
dst[0] = uint8(length-1)<<2 | tagCopy2
|
|
return 3
|
|
}
|
|
// Emit the remaining copy, encoded as 2 bytes.
|
|
dst[1] = uint8(offset)
|
|
dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
|
|
return 2
|
|
}
|
|
|
|
// matchLen returns how many bytes match in a and b
|
|
//
|
|
// It assumes that:
|
|
// len(a) <= len(b)
|
|
//
|
|
func matchLen(a []byte, b []byte) int {
|
|
b = b[:len(a)]
|
|
var checked int
|
|
if len(a) > 4 {
|
|
// Try 4 bytes first
|
|
if diff := load32(a, 0) ^ load32(b, 0); diff != 0 {
|
|
return bits.TrailingZeros32(diff) >> 3
|
|
}
|
|
// Switch to 8 byte matching.
|
|
checked = 4
|
|
a = a[4:]
|
|
b = b[4:]
|
|
for len(a) >= 8 {
|
|
b = b[:len(a)]
|
|
if diff := load64(a, 0) ^ load64(b, 0); diff != 0 {
|
|
return checked + (bits.TrailingZeros64(diff) >> 3)
|
|
}
|
|
checked += 8
|
|
a = a[8:]
|
|
b = b[8:]
|
|
}
|
|
}
|
|
b = b[:len(a)]
|
|
for i := range a {
|
|
if a[i] != b[i] {
|
|
return int(i) + checked
|
|
}
|
|
}
|
|
return len(a) + checked
|
|
}
|