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// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package zstdframe
import (
"math/bits"
"math/rand/v2"
"os"
"runtime"
"strings"
"sync"
"testing"
"github.com/klauspost/compress/zstd"
"tailscale.com/util/must"
)
// Use the concatenation of all Go source files in zstdframe as testdata.
var src = func() (out []byte) {
for _, de := range must.Get(os.ReadDir(".")) {
if strings.HasSuffix(de.Name(), ".go") {
out = append(out, must.Get(os.ReadFile(de.Name()))...)
}
}
return out
}()
var dst []byte
var dsts [][]byte
// zstdEnc is identical to getEncoder without options,
// except it relies on concurrency managed by the zstd package itself.
var zstdEnc = must.Get(zstd.NewWriter(nil,
zstd.WithEncoderConcurrency(runtime.NumCPU()),
zstd.WithSingleSegment(true),
zstd.WithZeroFrames(true),
zstd.WithEncoderLevel(zstd.SpeedDefault),
zstd.WithEncoderCRC(true),
zstd.WithLowerEncoderMem(false)))
// zstdDec is identical to getDecoder without options,
// except it relies on concurrency managed by the zstd package itself.
var zstdDec = must.Get(zstd.NewReader(nil,
zstd.WithDecoderConcurrency(runtime.NumCPU()),
zstd.WithDecoderMaxMemory(1<<63),
zstd.IgnoreChecksum(false),
zstd.WithDecoderLowmem(false)))
var coders = []struct {
name string
appendEncode func([]byte, []byte) []byte
appendDecode func([]byte, []byte) ([]byte, error)
}{{
name: "zstd",
appendEncode: func(dst, src []byte) []byte { return zstdEnc.EncodeAll(src, dst) },
appendDecode: func(dst, src []byte) ([]byte, error) { return zstdDec.DecodeAll(src, dst) },
}, {
name: "zstdframe",
appendEncode: func(dst, src []byte) []byte { return AppendEncode(dst, src) },
appendDecode: func(dst, src []byte) ([]byte, error) { return AppendDecode(dst, src) },
}}
func TestDecodeMaxSize(t *testing.T) {
var enc, dec []byte
zeros := make([]byte, 1<<16, 2<<16)
check := func(encSize, maxDecSize int) {
var gotErr, wantErr error
enc = AppendEncode(enc[:0], zeros[:encSize])
// Directly calling zstd.Decoder.DecodeAll may not trigger size check
// since it only operates on closest power-of-two.
dec, gotErr = func() ([]byte, error) {
d := getDecoder(MaxDecodedSize(uint64(maxDecSize)))
defer putDecoder(d)
return d.Decoder.DecodeAll(enc, dec[:0]) // directly call zstd.Decoder.DecodeAll
}()
if encSize > 1<<(64-bits.LeadingZeros64(uint64(maxDecSize)-1)) {
wantErr = zstd.ErrDecoderSizeExceeded
}
if gotErr != wantErr {
t.Errorf("DecodeAll(AppendEncode(%d), %d) error = %v, want %v", encSize, maxDecSize, gotErr, wantErr)
}
// Calling AppendDecode should perform the exact size check.
dec, gotErr = AppendDecode(dec[:0], enc, MaxDecodedSize(uint64(maxDecSize)))
if encSize > maxDecSize {
wantErr = zstd.ErrDecoderSizeExceeded
}
if gotErr != wantErr {
t.Errorf("AppendDecode(AppendEncode(%d), %d) error = %v, want %v", encSize, maxDecSize, gotErr, wantErr)
}
}
rn := rand.New(rand.NewPCG(0, 0))
for n := 1 << 10; n <= len(zeros); n <<= 1 {
nl := rn.IntN(n + 1)
check(nl, nl)
check(nl, nl-1)
check(nl, (n+nl)/2)
check(nl, n)
check((n+nl)/2, n)
check(n-1, n-1)
check(n-1, n)
check(n-1, n+1)
check(n, n-1)
check(n, n)
check(n, n+1)
check(n+1, n-1)
check(n+1, n)
check(n+1, n+1)
}
}
func BenchmarkEncode(b *testing.B) {
options := []struct {
name string
opts []Option
}{
{name: "Best", opts: []Option{BestCompression}},
{name: "Better", opts: []Option{BetterCompression}},
{name: "Default", opts: []Option{DefaultCompression}},
{name: "Fastest", opts: []Option{FastestCompression}},
{name: "FastestLowMemory", opts: []Option{FastestCompression, LowMemory(true)}},
{name: "FastestWindowSize", opts: []Option{FastestCompression, MaxWindowSize(1 << 10)}},
{name: "FastestNoChecksum", opts: []Option{FastestCompression, WithChecksum(false)}},
}
for _, bb := range options {
b.Run(bb.name, func(b *testing.B) {
b.ReportAllocs()
b.SetBytes(int64(len(src)))
for b.Loop() {
dst = AppendEncode(dst[:0], src, bb.opts...)
}
})
if testing.Verbose() {
ratio := float64(len(src)) / float64(len(dst))
b.Logf("ratio: %0.3fx", ratio)
}
}
}
func BenchmarkDecode(b *testing.B) {
options := []struct {
name string
opts []Option
}{
{name: "Checksum", opts: []Option{WithChecksum(true)}},
{name: "NoChecksum", opts: []Option{WithChecksum(false)}},
{name: "LowMemory", opts: []Option{LowMemory(true)}},
}
src := AppendEncode(nil, src)
for _, bb := range options {
b.Run(bb.name, func(b *testing.B) {
b.ReportAllocs()
b.SetBytes(int64(len(src)))
for b.Loop() {
dst = must.Get(AppendDecode(dst[:0], src, bb.opts...))
}
})
}
}
func BenchmarkEncodeParallel(b *testing.B) {
numCPU := runtime.NumCPU()
for _, coder := range coders {
dsts = dsts[:0]
for range numCPU {
dsts = append(dsts, coder.appendEncode(nil, src))
}
b.Run(coder.name, func(b *testing.B) {
b.ReportAllocs()
for b.Loop() {
var wg sync.WaitGroup
for j := range numCPU {
wg.Go(func() {
dsts[j] = coder.appendEncode(dsts[j][:0], src)
})
}
wg.Wait()
}
})
}
}
func BenchmarkDecodeParallel(b *testing.B) {
numCPU := runtime.NumCPU()
for _, coder := range coders {
dsts = dsts[:0]
src := AppendEncode(nil, src)
for range numCPU {
dsts = append(dsts, must.Get(coder.appendDecode(nil, src)))
}
b.Run(coder.name, func(b *testing.B) {
b.ReportAllocs()
for b.Loop() {
var wg sync.WaitGroup
for j := range numCPU {
wg.Go(func() {
dsts[j] = must.Get(coder.appendDecode(dsts[j][:0], src))
})
}
wg.Wait()
}
})
}
}
var opt Option
func TestOptionAllocs(t *testing.T) {
t.Run("EncoderLevel", func(t *testing.T) {
t.Log(testing.AllocsPerRun(1e3, func() { opt = EncoderLevel(zstd.SpeedFastest) }))
})
t.Run("MaxDecodedSize/PowerOfTwo", func(t *testing.T) {
t.Log(testing.AllocsPerRun(1e3, func() { opt = MaxDecodedSize(1024) }))
})
t.Run("MaxDecodedSize/Prime", func(t *testing.T) {
t.Log(testing.AllocsPerRun(1e3, func() { opt = MaxDecodedSize(1021) }))
})
t.Run("MaxWindowSize", func(t *testing.T) {
t.Log(testing.AllocsPerRun(1e3, func() { opt = MaxWindowSize(1024) }))
})
t.Run("LowMemory", func(t *testing.T) {
t.Log(testing.AllocsPerRun(1e3, func() { opt = LowMemory(true) }))
})
}
func TestGetDecoderAllocs(t *testing.T) {
t.Log(testing.AllocsPerRun(1e3, func() { getDecoder() }))
}
func TestGetEncoderAllocs(t *testing.T) {
t.Log(testing.AllocsPerRun(1e3, func() { getEncoder() }))
}
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