ref: df1f2fb3daa1acd25c88510f259d5535fb482126
dir: /internal/compress/flate/writer_test.go/
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package flate
import (
"archive/zip"
"bytes"
"compress/flate"
"fmt"
"io"
"math"
"math/rand"
"os"
"runtime"
"strconv"
"strings"
"testing"
)
func TestWriterMemUsage(t *testing.T) {
testMem := func(t *testing.T, fn func()) {
var before, after runtime.MemStats
runtime.GC()
runtime.ReadMemStats(&before)
fn()
runtime.GC()
runtime.ReadMemStats(&after)
t.Logf("%s: Memory Used: %dKB, %d allocs", t.Name(), (after.HeapInuse-before.HeapInuse)/1024, after.HeapObjects-before.HeapObjects)
}
data := make([]byte, 100000)
t.Run("stateless", func(t *testing.T) {
testMem(t, func() {
StatelessDeflate(io.Discard, data, false, nil)
})
})
for level := HuffmanOnly; level <= BestCompression; level++ {
t.Run(fmt.Sprint("level-", level), func(t *testing.T) {
var zr *Writer
var err error
testMem(t, func() {
zr, err = NewWriter(io.Discard, level)
if err != nil {
t.Fatal(err)
}
zr.Write(data)
})
zr.Close()
})
}
for level := HuffmanOnly; level <= BestCompression; level++ {
t.Run(fmt.Sprint("stdlib-", level), func(t *testing.T) {
var zr *flate.Writer
var err error
testMem(t, func() {
zr, err = flate.NewWriter(io.Discard, level)
if err != nil {
t.Fatal(err)
}
zr.Write(data)
})
zr.Close()
})
}
}
func TestWriterRegression(t *testing.T) {
data, err := os.ReadFile("testdata/regression.zip")
if err != nil {
t.Fatal(err)
}
for level := HuffmanOnly; level <= BestCompression; level++ {
t.Run(fmt.Sprint("level_", level), func(t *testing.T) {
zr, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
if err != nil {
t.Fatal(err)
}
for _, tt := range zr.File {
if !strings.HasSuffix(t.Name(), "") {
continue
}
t.Run(tt.Name, func(t *testing.T) {
if testing.Short() && tt.FileInfo().Size() > 10000 {
t.SkipNow()
}
r, err := tt.Open()
if err != nil {
t.Error(err)
return
}
in, err := io.ReadAll(r)
if err != nil {
t.Error(err)
}
msg := "level " + strconv.Itoa(level) + ":"
buf := new(bytes.Buffer)
fw, err := NewWriter(buf, level)
if err != nil {
t.Fatal(msg + err.Error())
}
n, err := fw.Write(in)
if n != len(in) {
t.Fatal(msg + "short write")
}
if err != nil {
t.Fatal(msg + err.Error())
}
err = fw.Close()
if err != nil {
t.Fatal(msg + err.Error())
}
fr1 := NewReader(buf)
data2, err := io.ReadAll(fr1)
if err != nil {
t.Fatal(msg + err.Error())
}
if !bytes.Equal(in, data2) {
t.Fatal(msg + "not equal")
}
// Do it again...
msg = "level " + strconv.Itoa(level) + " (reset):"
buf.Reset()
fw.Reset(buf)
n, err = fw.Write(in)
if n != len(in) {
t.Fatal(msg + "short write")
}
if err != nil {
t.Fatal(msg + err.Error())
}
err = fw.Close()
if err != nil {
t.Fatal(msg + err.Error())
}
fr1 = NewReader(buf)
data2, err = io.ReadAll(fr1)
if err != nil {
t.Fatal(msg + err.Error())
}
if !bytes.Equal(in, data2) {
t.Fatal(msg + "not equal")
}
})
}
})
}
}
func benchmarkEncoder(b *testing.B, testfile, level, n int) {
b.SetBytes(int64(n))
buf0, err := os.ReadFile(testfiles[testfile])
if err != nil {
b.Fatal(err)
}
if len(buf0) == 0 {
b.Fatalf("test file %q has no data", testfiles[testfile])
}
buf1 := make([]byte, n)
for i := 0; i < n; i += len(buf0) {
if len(buf0) > n-i {
buf0 = buf0[:n-i]
}
copy(buf1[i:], buf0)
}
buf0 = nil
runtime.GC()
w, err := NewWriter(io.Discard, level)
if err != nil {
b.Fatal(err)
}
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
w.Reset(io.Discard)
_, err = w.Write(buf1)
if err != nil {
b.Fatal(err)
}
err = w.Close()
if err != nil {
b.Fatal(err)
}
}
}
func BenchmarkEncodeDigitsConstant1e4(b *testing.B) { benchmarkEncoder(b, digits, constant, 1e4) }
func BenchmarkEncodeDigitsConstant1e5(b *testing.B) { benchmarkEncoder(b, digits, constant, 1e5) }
func BenchmarkEncodeDigitsConstant1e6(b *testing.B) { benchmarkEncoder(b, digits, constant, 1e6) }
func BenchmarkEncodeDigitsSpeed1e4(b *testing.B) { benchmarkEncoder(b, digits, speed, 1e4) }
func BenchmarkEncodeDigitsSpeed1e5(b *testing.B) { benchmarkEncoder(b, digits, speed, 1e5) }
func BenchmarkEncodeDigitsSpeed1e6(b *testing.B) { benchmarkEncoder(b, digits, speed, 1e6) }
func BenchmarkEncodeDigitsDefault1e4(b *testing.B) { benchmarkEncoder(b, digits, default_, 1e4) }
func BenchmarkEncodeDigitsDefault1e5(b *testing.B) { benchmarkEncoder(b, digits, default_, 1e5) }
func BenchmarkEncodeDigitsDefault1e6(b *testing.B) { benchmarkEncoder(b, digits, default_, 1e6) }
func BenchmarkEncodeDigitsCompress1e4(b *testing.B) { benchmarkEncoder(b, digits, compress, 1e4) }
func BenchmarkEncodeDigitsCompress1e5(b *testing.B) { benchmarkEncoder(b, digits, compress, 1e5) }
func BenchmarkEncodeDigitsCompress1e6(b *testing.B) { benchmarkEncoder(b, digits, compress, 1e6) }
func BenchmarkEncodeDigitsSL1e4(b *testing.B) { benchmarkStatelessEncoder(b, digits, 1e4) }
func BenchmarkEncodeDigitsSL1e5(b *testing.B) { benchmarkStatelessEncoder(b, digits, 1e5) }
func BenchmarkEncodeDigitsSL1e6(b *testing.B) { benchmarkStatelessEncoder(b, digits, 1e6) }
func BenchmarkEncodeTwainConstant1e4(b *testing.B) { benchmarkEncoder(b, twain, constant, 1e4) }
func BenchmarkEncodeTwainConstant1e5(b *testing.B) { benchmarkEncoder(b, twain, constant, 1e5) }
func BenchmarkEncodeTwainConstant1e6(b *testing.B) { benchmarkEncoder(b, twain, constant, 1e6) }
func BenchmarkEncodeTwainSpeed1e4(b *testing.B) { benchmarkEncoder(b, twain, speed, 1e4) }
func BenchmarkEncodeTwainSpeed1e5(b *testing.B) { benchmarkEncoder(b, twain, speed, 1e5) }
func BenchmarkEncodeTwainSpeed1e6(b *testing.B) { benchmarkEncoder(b, twain, speed, 1e6) }
func BenchmarkEncodeTwainDefault1e4(b *testing.B) { benchmarkEncoder(b, twain, default_, 1e4) }
func BenchmarkEncodeTwainDefault1e5(b *testing.B) { benchmarkEncoder(b, twain, default_, 1e5) }
func BenchmarkEncodeTwainDefault1e6(b *testing.B) { benchmarkEncoder(b, twain, default_, 1e6) }
func BenchmarkEncodeTwainCompress1e4(b *testing.B) { benchmarkEncoder(b, twain, compress, 1e4) }
func BenchmarkEncodeTwainCompress1e5(b *testing.B) { benchmarkEncoder(b, twain, compress, 1e5) }
func BenchmarkEncodeTwainCompress1e6(b *testing.B) { benchmarkEncoder(b, twain, compress, 1e6) }
func BenchmarkEncodeTwainSL1e4(b *testing.B) { benchmarkStatelessEncoder(b, twain, 1e4) }
func BenchmarkEncodeTwainSL1e5(b *testing.B) { benchmarkStatelessEncoder(b, twain, 1e5) }
func BenchmarkEncodeTwainSL1e6(b *testing.B) { benchmarkStatelessEncoder(b, twain, 1e6) }
func BenchmarkEncodeTwain1024Win1e4(b *testing.B) { benchmarkEncoder(b, twain, oneK, 1e4) }
func BenchmarkEncodeTwain1024Win1e5(b *testing.B) { benchmarkEncoder(b, twain, oneK, 1e5) }
func BenchmarkEncodeTwain1024Win1e6(b *testing.B) { benchmarkEncoder(b, twain, oneK, 1e6) }
func benchmarkStatelessEncoder(b *testing.B, testfile, n int) {
b.SetBytes(int64(n))
buf0, err := os.ReadFile(testfiles[testfile])
if err != nil {
b.Fatal(err)
}
if len(buf0) == 0 {
b.Fatalf("test file %q has no data", testfiles[testfile])
}
buf1 := make([]byte, n)
for i := 0; i < n; i += len(buf0) {
if len(buf0) > n-i {
buf0 = buf0[:n-i]
}
copy(buf1[i:], buf0)
}
buf0 = nil
runtime.GC()
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
w := NewStatelessWriter(io.Discard)
_, err = w.Write(buf1)
if err != nil {
b.Fatal(err)
}
err = w.Close()
if err != nil {
b.Fatal(err)
}
}
}
// A writer that fails after N writes.
type errorWriter struct {
N int
}
func (e *errorWriter) Write(b []byte) (int, error) {
if e.N <= 0 {
return 0, io.ErrClosedPipe
}
e.N--
return len(b), nil
}
// Test if errors from the underlying writer is passed upwards.
func TestWriteError(t *testing.T) {
buf := new(bytes.Buffer)
n := 65536
if !testing.Short() {
n *= 4
}
for i := 0; i < n; i++ {
fmt.Fprintf(buf, "asdasfasf%d%dfghfgujyut%dyutyu\n", i, i, i)
}
in := buf.Bytes()
// We create our own buffer to control number of writes.
copyBuf := make([]byte, 128)
for l := range 10 {
for fail := 1; fail <= 256; fail *= 2 {
// Fail after 'fail' writes
ew := &errorWriter{N: fail}
w, err := NewWriter(ew, l)
if err != nil {
t.Fatalf("NewWriter: level %d: %v", l, err)
}
n, err := copyBuffer(w, bytes.NewBuffer(in), copyBuf)
if err == nil {
t.Fatalf("Level %d: Expected an error, writer was %#v", l, ew)
}
n2, err := w.Write([]byte{1, 2, 2, 3, 4, 5})
if n2 != 0 {
t.Fatal("Level", l, "Expected 0 length write, got", n)
}
if err == nil {
t.Fatal("Level", l, "Expected an error")
}
err = w.Flush()
if err == nil {
t.Fatal("Level", l, "Expected an error on flush")
}
err = w.Close()
if err == nil {
t.Fatal("Level", l, "Expected an error on close")
}
w.Reset(io.Discard)
n2, err = w.Write([]byte{1, 2, 3, 4, 5, 6})
if err != nil {
t.Fatal("Level", l, "Got unexpected error after reset:", err)
}
if n2 == 0 {
t.Fatal("Level", l, "Got 0 length write, expected > 0")
}
if testing.Short() {
return
}
}
}
}
// Test if errors from the underlying writer is passed upwards.
func TestWriter_Reset(t *testing.T) {
buf := new(bytes.Buffer)
n := 65536
if !testing.Short() {
n *= 4
}
for i := 0; i < n; i++ {
fmt.Fprintf(buf, "asdasfasf%d%dfghfgujyut%dyutyu\n", i, i, i)
}
in := buf.Bytes()
for l := range 10 {
if testing.Short() && l > 1 {
continue
}
t.Run(fmt.Sprintf("level-%d", l), func(t *testing.T) {
t.Parallel()
offset := 1
if testing.Short() {
offset = 256
}
for ; offset <= 256; offset *= 2 {
// Fail after 'fail' writes
w, err := NewWriter(io.Discard, l)
if err != nil {
t.Fatalf("NewWriter: level %d: %v", l, err)
}
if w.d.fast == nil {
t.Skip("Not Fast...")
return
}
for i := 0; i < (bufferReset-len(in)-offset-maxMatchOffset)/maxMatchOffset; i++ {
// skip ahead to where we are close to wrap around...
w.d.fast.Reset()
}
w.d.fast.Reset()
_, err = w.Write(in)
if err != nil {
t.Fatal(err)
}
for range 50 {
// skip ahead again... This should wrap around...
w.d.fast.Reset()
}
w.d.fast.Reset()
_, err = w.Write(in)
if err != nil {
t.Fatal(err)
}
for range (math.MaxUint32 - bufferReset) / maxMatchOffset {
// skip ahead to where we are close to wrap around...
w.d.fast.Reset()
}
_, err = w.Write(in)
if err != nil {
t.Fatal(err)
}
err = w.Close()
if err != nil {
t.Fatal(err)
}
}
})
}
}
func TestDeterministicL1(t *testing.T) { testDeterministic(1, t) }
func TestDeterministicL2(t *testing.T) { testDeterministic(2, t) }
func TestDeterministicL3(t *testing.T) { testDeterministic(3, t) }
func TestDeterministicL4(t *testing.T) { testDeterministic(4, t) }
func TestDeterministicL5(t *testing.T) { testDeterministic(5, t) }
func TestDeterministicL6(t *testing.T) { testDeterministic(6, t) }
func TestDeterministicL7(t *testing.T) { testDeterministic(7, t) }
func TestDeterministicL8(t *testing.T) { testDeterministic(8, t) }
func TestDeterministicL9(t *testing.T) { testDeterministic(9, t) }
func TestDeterministicL0(t *testing.T) { testDeterministic(0, t) }
func TestDeterministicLM2(t *testing.T) { testDeterministic(-2, t) }
func testDeterministic(i int, t *testing.T) {
// Test so much we cross a good number of block boundaries.
length := maxStoreBlockSize*30 + 500
if testing.Short() {
length /= 10
}
// Create a random, but compressible stream.
rng := rand.New(rand.NewSource(1))
t1 := make([]byte, length)
for i := range t1 {
t1[i] = byte(rng.Int63() & 7)
}
// Do our first encode.
var b1 bytes.Buffer
br := bytes.NewBuffer(t1)
w, err := NewWriter(&b1, i)
if err != nil {
t.Fatal(err)
}
// Use a very small prime sized buffer.
cbuf := make([]byte, 787)
_, err = copyBuffer(w, br, cbuf)
if err != nil {
t.Fatal(err)
}
w.Close()
// We choose a different buffer size,
// bigger than a maximum block, and also a prime.
var b2 bytes.Buffer
cbuf = make([]byte, 81761)
br2 := bytes.NewBuffer(t1)
w2, err := NewWriter(&b2, i)
if err != nil {
t.Fatal(err)
}
_, err = copyBuffer(w2, br2, cbuf)
if err != nil {
t.Fatal(err)
}
w2.Close()
b1b := b1.Bytes()
b2b := b2.Bytes()
if !bytes.Equal(b1b, b2b) {
t.Errorf("level %d did not produce deterministic result, result mismatch, len(a) = %d, len(b) = %d", i, len(b1b), len(b2b))
}
// Test using io.WriterTo interface.
var b3 bytes.Buffer
br = bytes.NewBuffer(t1)
w, err = NewWriter(&b3, i)
if err != nil {
t.Fatal(err)
}
_, err = br.WriteTo(w)
if err != nil {
t.Fatal(err)
}
w.Close()
b3b := b3.Bytes()
if !bytes.Equal(b1b, b3b) {
t.Errorf("level %d (io.WriterTo) did not produce deterministic result, result mismatch, len(a) = %d, len(b) = %d", i, len(b1b), len(b3b))
}
}
// copyBuffer is a copy of io.CopyBuffer, since we want to support older go versions.
// This is modified to never use io.WriterTo or io.ReaderFrom interfaces.
func copyBuffer(dst io.Writer, src io.Reader, buf []byte) (written int64, err error) {
if buf == nil {
buf = make([]byte, 32*1024)
}
for {
nr, er := src.Read(buf)
if nr > 0 {
nw, ew := dst.Write(buf[0:nr])
if nw > 0 {
written += int64(nw)
}
if ew != nil {
err = ew
break
}
if nr != nw {
err = io.ErrShortWrite
break
}
}
if er == io.EOF {
break
}
if er != nil {
err = er
break
}
}
return written, err
}
func BenchmarkCompressAllocations(b *testing.B) {
payload := []byte(strings.Repeat("Tiny payload", 20))
for j := -2; j <= 9; j++ {
b.Run("level("+strconv.Itoa(j)+")", func(b *testing.B) {
b.Run("flate", func(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
w, err := NewWriter(io.Discard, j)
if err != nil {
b.Fatal(err)
}
w.Write(payload)
w.Close()
}
})
})
}
}
func BenchmarkCompressAllocationsSingle(b *testing.B) {
payload := []byte(strings.Repeat("Tiny payload", 20))
const level = 2
b.Run("flate", func(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
w, err := NewWriter(io.Discard, level)
if err != nil {
b.Fatal(err)
}
w.Write(payload)
w.Close()
}
})
}