// Copyright 2009 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 (
"bytes"
"errors"
"fmt"
"internal/testenv"
"io"
"io/ioutil"
"reflect"
"runtime/debug"
"sync"
"testing"
)
type deflateTest struct {
in []byte
level int
out []byte
}
type deflateInflateTest struct {
in []byte
}
type reverseBitsTest struct {
in uint16
bitCount uint8
out uint16
}
var deflateTests = []*deflateTest{
{[]byte{}, 0, []byte{1, 0, 0, 255, 255}},
{[]byte{0x11}, -1, []byte{18, 4, 4, 0, 0, 255, 255}},
{[]byte{0x11}, DefaultCompression, []byte{18, 4, 4, 0, 0, 255, 255}},
{[]byte{0x11}, 4, []byte{18, 4, 4, 0, 0, 255, 255}},
{[]byte{0x11}, 0, []byte{0, 1, 0, 254, 255, 17, 1, 0, 0, 255, 255}},
{[]byte{0x11, 0x12}, 0, []byte{0, 2, 0, 253, 255, 17, 18, 1, 0, 0, 255, 255}},
{[]byte{0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11}, 0,
[]byte{0, 8, 0, 247, 255, 17, 17, 17, 17, 17, 17, 17, 17, 1, 0, 0, 255, 255},
},
{[]byte{}, 2, []byte{1, 0, 0, 255, 255}},
{[]byte{0x11}, 2, []byte{18, 4, 4, 0, 0, 255, 255}},
{[]byte{0x11, 0x12}, 2, []byte{18, 20, 2, 4, 0, 0, 255, 255}},
{[]byte{0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11}, 2, []byte{18, 132, 2, 64, 0, 0, 0, 255, 255}},
{[]byte{}, 9, []byte{1, 0, 0, 255, 255}},
{[]byte{0x11}, 9, []byte{18, 4, 4, 0, 0, 255, 255}},
{[]byte{0x11, 0x12}, 9, []byte{18, 20, 2, 4, 0, 0, 255, 255}},
{[]byte{0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11}, 9, []byte{18, 132, 2, 64, 0, 0, 0, 255, 255}},
}
var deflateInflateTests = []*deflateInflateTest{
{[]byte{}},
{[]byte{0x11}},
{[]byte{0x11, 0x12}},
{[]byte{0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11}},
{[]byte{0x11, 0x10, 0x13, 0x41, 0x21, 0x21, 0x41, 0x13, 0x87, 0x78, 0x13}},
{largeDataChunk()},
}
var reverseBitsTests = []*reverseBitsTest{
{1, 1, 1},
{1, 2, 2},
{1, 3, 4},
{1, 4, 8},
{1, 5, 16},
{17, 5, 17},
{257, 9, 257},
{29, 5, 23},
}
func largeDataChunk() []byte {
result := make([]byte, 100000)
for i := range result {
result[i] = byte(i * i & 0xFF)
}
return result
}
func TestBulkHash4(t *testing.T) {
for _, x := range deflateTests {
y := x.out
if len(y) < minMatchLength {
continue
}
y = append(y, y...)
for j := 4; j < len(y); j++ {
y := y[:j]
dst := make([]uint32, len(y)-minMatchLength+1)
for i := range dst {
dst[i] = uint32(i + 100)
}
bulkHash4(y, dst)
for i, got := range dst {
want := hash4(y[i:])
if got != want && got == uint32(i)+100 {
t.Errorf("Len:%d Index:%d, want 0x%08x but not modified", len(y), i, want)
} else if got != want {
t.Errorf("Len:%d Index:%d, got 0x%08x want:0x%08x", len(y), i, got, want)
}
}
}
}
}
func TestDeflate(t *testing.T) {
for _, h := range deflateTests {
var buf bytes.Buffer
w, err := NewWriter(&buf, h.level)
if err != nil {
t.Errorf("NewWriter: %v", err)
continue
}
w.Write(h.in)
w.Close()
if !bytes.Equal(buf.Bytes(), h.out) {
t.Errorf("Deflate(%d, %x) = \n%#v, want \n%#v", h.level, h.in, buf.Bytes(), h.out)
}
}
}
// A sparseReader returns a stream consisting of 0s followed by 1<<16 1s.
// This tests missing hash references in a very large input.
type sparseReader struct {
l int64
cur int64
}
func (r *sparseReader) Read(b []byte) (n int, err error) {
if r.cur >= r.l {
return 0, io.EOF
}
n = len(b)
cur := r.cur + int64(n)
if cur > r.l {
n -= int(cur - r.l)
cur = r.l
}
for i := range b[0:n] {
if r.cur+int64(i) >= r.l-1<<16 {
b[i] = 1
} else {
b[i] = 0
}
}
r.cur = cur
return
}
func TestVeryLongSparseChunk(t *testing.T) {
if testing.Short() {
t.Skip("skipping sparse chunk during short test")
}
w, err := NewWriter(ioutil.Discard, 1)
if err != nil {
t.Errorf("NewWriter: %v", err)
return
}
if _, err = io.Copy(w, &sparseReader{l: 23e8}); err != nil {
t.Errorf("Compress failed: %v", err)
return
}
}
type syncBuffer struct {
buf bytes.Buffer
mu sync.RWMutex
closed bool
ready chan bool
}
func newSyncBuffer() *syncBuffer {
return &syncBuffer{ready: make(chan bool, 1)}
}
func (b *syncBuffer) Read(p []byte) (n int, err error) {
for {
b.mu.RLock()
n, err = b.buf.Read(p)
b.mu.RUnlock()
if n > 0 || b.closed {
return
}
<-b.ready
}
}
func (b *syncBuffer) signal() {
select {
case b.ready <- true:
default:
}
}
func (b *syncBuffer) Write(p []byte) (n int, err error) {
n, err = b.buf.Write(p)
b.signal()
return
}
func (b *syncBuffer) WriteMode() {
b.mu.Lock()
}
func (b *syncBuffer) ReadMode() {
b.mu.Unlock()
b.signal()
}
func (b *syncBuffer) Close() error {
b.closed = true
b.signal()
return nil
}
func testSync(t *testing.T, level int, input []byte, name string) {
if len(input) == 0 {
return
}
t.Logf("--testSync %d, %d, %s", level, len(input), name)
buf := newSyncBuffer()
buf1 := new(bytes.Buffer)
buf.WriteMode()
w, err := NewWriter(io.MultiWriter(buf, buf1), level)
if err != nil {
t.Errorf("NewWriter: %v", err)
return
}
r := NewReader(buf)
// Write half the input and read back.
for i := 0; i < 2; i++ {
var lo, hi int
if i == 0 {
lo, hi = 0, (len(input)+1)/2
} else {
lo, hi = (len(input)+1)/2, len(input)
}
t.Logf("#%d: write %d-%d", i, lo, hi)
if _, err := w.Write(input[lo:hi]); err != nil {
t.Errorf("testSync: write: %v", err)
return
}
if i == 0 {
if err := w.Flush(); err != nil {
t.Errorf("testSync: flush: %v", err)
return
}
} else {
if err := w.Close(); err != nil {
t.Errorf("testSync: close: %v", err)
}
}
buf.ReadMode()
out := make([]byte, hi-lo+1)
m, err := io.ReadAtLeast(r, out, hi-lo)
t.Logf("#%d: read %d", i, m)
if m != hi-lo || err != nil {
t.Errorf("testSync/%d (%d, %d, %s): read %d: %d, %v (%d left)", i, level, len(input), name, hi-lo, m, err, buf.buf.Len())
return
}
if !bytes.Equal(input[lo:hi], out[:hi-lo]) {
t.Errorf("testSync/%d: read wrong bytes: %x vs %x", i, input[lo:hi], out[:hi-lo])
return
}
// This test originally checked that after reading
// the first half of the input, there was nothing left
// in the read buffer (buf.buf.Len() != 0) but that is
// not necessarily the case: the write Flush may emit
// some extra framing bits that are not necessary
// to process to obtain the first half of the uncompressed
// data. The test ran correctly most of the time, because
// the background goroutine had usually read even
// those extra bits by now, but it's not a useful thing to
// check.
buf.WriteMode()
}
buf.ReadMode()
out := make([]byte, 10)
if n, err := r.Read(out); n > 0 || err != io.EOF {
t.Errorf("testSync (%d, %d, %s): final Read: %d, %v (hex: %x)", level, len(input), name, n, err, out[0:n])
}
if buf.buf.Len() != 0 {
t.Errorf("testSync (%d, %d, %s): extra data at end", level, len(input), name)
}
r.Close()
// stream should work for ordinary reader too
r = NewReader(buf1)
out, err = ioutil.ReadAll(r)
if err != nil {
t.Errorf("testSync: read: %s", err)
return
}
r.Close()
if !bytes.Equal(input, out) {
t.Errorf("testSync: decompress(compress(data)) != data: level=%d input=%s", level, name)
}
}
func testToFromWithLevelAndLimit(t *testing.T, level int, input []byte, name string, limit int) {
var buffer bytes.Buffer
w, err := NewWriter(&buffer, level)
if err != nil {
t.Errorf("NewWriter: %v", err)
return
}
w.Write(input)
w.Close()
if limit > 0 && buffer.Len() > limit {
t.Errorf("level: %d, len(compress(data)) = %d > limit = %d", level, buffer.Len(), limit)
return
}
if limit > 0 {
t.Logf("level: %d, size:%.2f%%, %d b\n", level, float64(buffer.Len()*100)/float64(limit), buffer.Len())
}
r := NewReader(&buffer)
out, err := ioutil.ReadAll(r)
if err != nil {
t.Errorf("read: %s", err)
return
}
r.Close()
if !bytes.Equal(input, out) {
t.Errorf("decompress(compress(data)) != data: level=%d input=%s", level, name)
return
}
testSync(t, level, input, name)
}
func testToFromWithLimit(t *testing.T, input []byte, name string, limit [11]int) {
for i := 0; i < 10; i++ {
testToFromWithLevelAndLimit(t, i, input, name, limit[i])
}
// Test HuffmanCompression
testToFromWithLevelAndLimit(t, -2, input, name, limit[10])
}
func TestDeflateInflate(t *testing.T) {
t.Parallel()
for i, h := range deflateInflateTests {
if testing.Short() && len(h.in) > 10000 {
continue
}
testToFromWithLimit(t, h.in, fmt.Sprintf("#%d", i), [11]int{})
}
}
func TestReverseBits(t *testing.T) {
for _, h := range reverseBitsTests {
if v := reverseBits(h.in, h.bitCount); v != h.out {
t.Errorf("reverseBits(%v,%v) = %v, want %v",
h.in, h.bitCount, v, h.out)
}
}
}
type deflateInflateStringTest struct {
filename string
label string
limit [11]int
}
var deflateInflateStringTests = []deflateInflateStringTest{
{
"../testdata/e.txt",
"2.718281828...",
[...]int{100018, 50650, 50960, 51150, 50930, 50790, 50790, 50790, 50790, 50790, 43683},
},
{
"../../testdata/Isaac.Newton-Opticks.txt",
"Isaac.Newton-Opticks",
[...]int{567248, 218338, 198211, 193152, 181100, 175427, 175427, 173597, 173422, 173422, 325240},
},
}
func TestDeflateInflateString(t *testing.T) {
t.Parallel()
if testing.Short() && testenv.Builder() == "" {
t.Skip("skipping in short mode")
}
for _, test := range deflateInflateStringTests {
gold, err := ioutil.ReadFile(test.filename)
if err != nil {
t.Error(err)
}
testToFromWithLimit(t, gold, test.label, test.limit)
if testing.Short() {
break
}
}
}
func TestReaderDict(t *testing.T) {
const (
dict = "hello world"
text = "hello again world"
)
var b bytes.Buffer
w, err := NewWriter(&b, 5)
if err != nil {
t.Fatalf("NewWriter: %v", err)
}
w.Write([]byte(dict))
w.Flush()
b.Reset()
w.Write([]byte(text))
w.Close()
r := NewReaderDict(&b, []byte(dict))
data, err := ioutil.ReadAll(r)
if err != nil {
t.Fatal(err)
}
if string(data) != "hello again world" {
t.Fatalf("read returned %q want %q", string(data), text)
}
}
func TestWriterDict(t *testing.T) {
const (
dict = "hello world"
text = "hello again world"
)
var b bytes.Buffer
w, err := NewWriter(&b, 5)
if err != nil {
t.Fatalf("NewWriter: %v", err)
}
w.Write([]byte(dict))
w.Flush()
b.Reset()
w.Write([]byte(text))
w.Close()
var b1 bytes.Buffer
w, _ = NewWriterDict(&b1, 5, []byte(dict))
w.Write([]byte(text))
w.Close()
if !bytes.Equal(b1.Bytes(), b.Bytes()) {
t.Fatalf("writer wrote %q want %q", b1.Bytes(), b.Bytes())
}
}
// See https://golang.org/issue/2508
func TestRegression2508(t *testing.T) {
if testing.Short() {
t.Logf("test disabled with -short")
return
}
w, err := NewWriter(ioutil.Discard, 1)
if err != nil {
t.Fatalf("NewWriter: %v", err)
}
buf := make([]byte, 1024)
for i := 0; i < 131072; i++ {
if _, err := w.Write(buf); err != nil {
t.Fatalf("writer failed: %v", err)
}
}
w.Close()
}
func TestWriterReset(t *testing.T) {
t.Parallel()
for level := 0; level <= 9; level++ {
if testing.Short() && level > 1 {
break
}
w, err := NewWriter(ioutil.Discard, level)
if err != nil {
t.Fatalf("NewWriter: %v", err)
}
buf := []byte("hello world")
n := 1024
if testing.Short() {
n = 10
}
for i := 0; i < n; i++ {
w.Write(buf)
}
w.Reset(ioutil.Discard)
wref, err := NewWriter(ioutil.Discard, level)
if err != nil {
t.Fatalf("NewWriter: %v", err)
}
// DeepEqual doesn't compare functions.
w.d.fill, wref.d.fill = nil, nil
w.d.step, wref.d.step = nil, nil
w.d.bulkHasher, wref.d.bulkHasher = nil, nil
w.d.bestSpeed, wref.d.bestSpeed = nil, nil
// hashMatch is always overwritten when used.
copy(w.d.hashMatch[:], wref.d.hashMatch[:])
if len(w.d.tokens) != 0 {
t.Errorf("level %d Writer not reset after Reset. %d tokens were present", level, len(w.d.tokens))
}
// As long as the length is 0, we don't care about the content.
w.d.tokens = wref.d.tokens
// We don't care if there are values in the window, as long as it is at d.index is 0
w.d.window = wref.d.window
if !reflect.DeepEqual(w, wref) {
t.Errorf("level %d Writer not reset after Reset", level)
}
}
testResetOutput(t, func(w io.Writer) (*Writer, error) { return NewWriter(w, NoCompression) })
testResetOutput(t, func(w io.Writer) (*Writer, error) { return NewWriter(w, DefaultCompression) })
testResetOutput(t, func(w io.Writer) (*Writer, error) { return NewWriter(w, BestCompression) })
dict := []byte("we are the world")
testResetOutput(t, func(w io.Writer) (*Writer, error) { return NewWriterDict(w, NoCompression, dict) })
testResetOutput(t, func(w io.Writer) (*Writer, error) { return NewWriterDict(w, DefaultCompression, dict) })
testResetOutput(t, func(w io.Writer) (*Writer, error) { return NewWriterDict(w, BestCompression, dict) })
}
func testResetOutput(t *testing.T, newWriter func(w io.Writer) (*Writer, error)) {
buf := new(bytes.Buffer)
w, err := newWriter(buf)
if err != nil {
t.Fatalf("NewWriter: %v", err)
}
b := []byte("hello world")
for i := 0; i < 1024; i++ {
w.Write(b)
}
w.Close()
out1 := buf.Bytes()
buf2 := new(bytes.Buffer)
w.Reset(buf2)
for i := 0; i < 1024; i++ {
w.Write(b)
}
w.Close()
out2 := buf2.Bytes()
if len(out1) != len(out2) {
t.Errorf("got %d, expected %d bytes", len(out2), len(out1))
return
}
if !bytes.Equal(out1, out2) {
mm := 0
for i, b := range out1[:len(out2)] {
if b != out2[i] {
t.Errorf("mismatch index %d: %#02x, expected %#02x", i, out2[i], b)
}
mm++
if mm == 10 {
t.Fatal("Stopping")
}
}
}
t.Logf("got %d bytes", len(out1))
}
// TestBestSpeed tests that round-tripping through deflate and then inflate
// recovers the original input. The Write sizes are near the thresholds in the
// compressor.encSpeed method (0, 16, 128), as well as near maxStoreBlockSize
// (65535).
func TestBestSpeed(t *testing.T) {
t.Parallel()
abc := make([]byte, 128)
for i := range abc {
abc[i] = byte(i)
}
abcabc := bytes.Repeat(abc, 131072/len(abc))
var want []byte
testCases := [][]int{
{65536, 0},
{65536, 1},
{65536, 1, 256},
{65536, 1, 65536},
{65536, 14},
{65536, 15},
{65536, 16},
{65536, 16, 256},
{65536, 16, 65536},
{65536, 127},
{65536, 128},
{65536, 128, 256},
{65536, 128, 65536},
{65536, 129},
{65536, 65536, 256},
{65536, 65536, 65536},
}
for i, tc := range testCases {
if i >= 3 && testing.Short() {
break
}
for _, firstN := range []int{1, 65534, 65535, 65536, 65537, 131072} {
tc[0] = firstN
outer:
for _, flush := range []bool{false, true} {
buf := new(bytes.Buffer)
want = want[:0]
w, err := NewWriter(buf, BestSpeed)
if err != nil {
t.Errorf("i=%d, firstN=%d, flush=%t: NewWriter: %v", i, firstN, flush, err)
continue
}
for _, n := range tc {
want = append(want, abcabc[:n]...)
if _, err := w.Write(abcabc[:n]); err != nil {
t.Errorf("i=%d, firstN=%d, flush=%t: Write: %v", i, firstN, flush, err)
continue outer
}
if !flush {
continue
}
if err := w.Flush(); err != nil {
t.Errorf("i=%d, firstN=%d, flush=%t: Flush: %v", i, firstN, flush, err)
continue outer
}
}
if err := w.Close(); err != nil {
t.Errorf("i=%d, firstN=%d, flush=%t: Close: %v", i, firstN, flush, err)
continue
}
r := NewReader(buf)
got, err := ioutil.ReadAll(r)
if err != nil {
t.Errorf("i=%d, firstN=%d, flush=%t: ReadAll: %v", i, firstN, flush, err)
continue
}
r.Close()
if !bytes.Equal(got, want) {
t.Errorf("i=%d, firstN=%d, flush=%t: corruption during deflate-then-inflate", i, firstN, flush)
continue
}
}
}
}
}
var errIO = errors.New("IO error")
// failWriter fails with errIO exactly at the nth call to Write.
type failWriter struct{ n int }
func (w *failWriter) Write(b []byte) (int, error) {
w.n--
if w.n == -1 {
return 0, errIO
}
return len(b), nil
}
func TestWriterPersistentError(t *testing.T) {
t.Parallel()
d, err := ioutil.ReadFile("../../testdata/Isaac.Newton-Opticks.txt")
if err != nil {
t.Fatalf("ReadFile: %v", err)
}
d = d[:10000] // Keep this test short
zw, err := NewWriter(nil, DefaultCompression)
if err != nil {
t.Fatalf("NewWriter: %v", err)
}
// Sweep over the threshold at which an error is returned.
// The variable i makes it such that the ith call to failWriter.Write will
// return errIO. Since failWriter errors are not persistent, we must ensure
// that flate.Writer errors are persistent.
for i := 0; i < 1000; i++ {
fw := &failWriter{i}
zw.Reset(fw)
_, werr := zw.Write(d)
cerr := zw.Close()
if werr != errIO && werr != nil {
t.Errorf("test %d, mismatching Write error: got %v, want %v", i, werr, errIO)
}
if cerr != errIO && fw.n < 0 {
t.Errorf("test %d, mismatching Close error: got %v, want %v", i, cerr, errIO)
}
if fw.n >= 0 {
// At this point, the failure threshold was sufficiently high enough
// that we wrote the whole stream without any errors.
return
}
}
}
func TestBestSpeedMatch(t *testing.T) {
t.Parallel()
cases := []struct {
previous, current []byte
t, s, want int32
}{{
previous: []byte{0, 0, 0, 1, 2},
current: []byte{3, 4, 5, 0, 1, 2, 3, 4, 5},
t: -3,
s: 3,
want: 6,
}, {
previous: []byte{0, 0, 0, 1, 2},
current: []byte{2, 4, 5, 0, 1, 2, 3, 4, 5},
t: -3,
s: 3,
want: 3,
}, {
previous: []byte{0, 0, 0, 1, 1},
current: []byte{3, 4, 5, 0, 1, 2, 3, 4, 5},
t: -3,
s: 3,
want: 2,
}, {
previous: []byte{0, 0, 0, 1, 2},
current: []byte{2, 2, 2, 2, 1, 2, 3, 4, 5},
t: -1,
s: 0,
want: 4,
}, {
previous: []byte{0, 0, 0, 1, 2, 3, 4, 5, 2, 2},
current: []byte{2, 2, 2, 2, 1, 2, 3, 4, 5},
t: -7,
s: 4,
want: 5,
}, {
previous: []byte{9, 9, 9, 9, 9},
current: []byte{2, 2, 2, 2, 1, 2, 3, 4, 5},
t: -1,
s: 0,
want: 0,
}, {
previous: []byte{9, 9, 9, 9, 9},
current: []byte{9, 2, 2, 2, 1, 2, 3, 4, 5},
t: 0,
s: 1,
want: 0,
}, {
previous: []byte{},
current: []byte{9, 2, 2, 2, 1, 2, 3, 4, 5},
t: -5,
s: 1,
want: 0,
}, {
previous: []byte{},
current: []byte{9, 2, 2, 2, 1, 2, 3, 4, 5},
t: -1,
s: 1,
want: 0,
}, {
previous: []byte{},
current: []byte{2, 2, 2, 2, 1, 2, 3, 4, 5},
t: 0,
s: 1,
want: 3,
}, {
previous: []byte{3, 4, 5},
current: []byte{3, 4, 5},
t: -3,
s: 0,
want: 3,
}, {
previous: make([]byte, 1000),
current: make([]byte, 1000),
t: -1000,
s: 0,
want: maxMatchLength - 4,
}, {
previous: make([]byte, 200),
current: make([]byte, 500),
t: -200,
s: 0,
want: maxMatchLength - 4,
}, {
previous: make([]byte, 200),
current: make([]byte, 500),
t: 0,
s: 1,
want: maxMatchLength - 4,
}, {
previous: make([]byte, maxMatchLength-4),
current: make([]byte, 500),
t: -(maxMatchLength - 4),
s: 0,
want: maxMatchLength - 4,
}, {
previous: make([]byte, 200),
current: make([]byte, 500),
t: -200,
s: 400,
want: 100,
}, {
previous: make([]byte, 10),
current: make([]byte, 500),
t: 200,
s: 400,
want: 100,
}}
for i, c := range cases {
e := deflateFast{prev: c.previous}
got := e.matchLen(c.s, c.t, c.current)
if got != c.want {
t.Errorf("Test %d: match length, want %d, got %d", i, c.want, got)
}
}
}
func TestBestSpeedMaxMatchOffset(t *testing.T) {
t.Parallel()
const abc, xyz = "abcdefgh", "stuvwxyz"
for _, matchBefore := range []bool{false, true} {
for _, extra := range []int{0, inputMargin - 1, inputMargin, inputMargin + 1, 2 * inputMargin} {
for offsetAdj := -5; offsetAdj <= +5; offsetAdj++ {
report := func(desc string, err error) {
t.Errorf("matchBefore=%t, extra=%d, offsetAdj=%d: %s%v",
matchBefore, extra, offsetAdj, desc, err)
}
offset := maxMatchOffset + offsetAdj
// Make src to be a []byte of the form
// "%s%s%s%s%s" % (abc, zeros0, xyzMaybe, abc, zeros1)
// where:
// zeros0 is approximately maxMatchOffset zeros.
// xyzMaybe is either xyz or the empty string.
// zeros1 is between 0 and 30 zeros.
// The difference between the two abc's will be offset, which
// is maxMatchOffset plus or minus a small adjustment.
src := make([]byte, offset+len(abc)+extra)
copy(src, abc)
if !matchBefore {
copy(src[offset-len(xyz):], xyz)
}
copy(src[offset:], abc)
buf := new(bytes.Buffer)
w, err := NewWriter(buf, BestSpeed)
if err != nil {
report("NewWriter: ", err)
continue
}
if _, err := w.Write(src); err != nil {
report("Write: ", err)
continue
}
if err := w.Close(); err != nil {
report("Writer.Close: ", err)
continue
}
r := NewReader(buf)
dst, err := ioutil.ReadAll(r)
r.Close()
if err != nil {
report("ReadAll: ", err)
continue
}
if !bytes.Equal(dst, src) {
report("", fmt.Errorf("bytes differ after round-tripping"))
continue
}
}
}
}
}
func TestMaxStackSize(t *testing.T) {
// This test must not run in parallel with other tests as debug.SetMaxStack
// affects all goroutines.
n := debug.SetMaxStack(1 << 16)
defer debug.SetMaxStack(n)
var wg sync.WaitGroup
defer wg.Wait()
b := make([]byte, 1<<20)
for level := HuffmanOnly; level <= BestCompression; level++ {
// Run in separate goroutine to increase probability of stack regrowth.
wg.Add(1)
go func(level int) {
defer wg.Done()
zw, err := NewWriter(ioutil.Discard, level)
if err != nil {
t.Errorf("level %d, NewWriter() = %v, want nil", level, err)
}
if n, err := zw.Write(b); n != len(b) || err != nil {
t.Errorf("level %d, Write() = (%d, %v), want (%d, nil)", level, n, err, len(b))
}
if err := zw.Close(); err != nil {
t.Errorf("level %d, Close() = %v, want nil", level, err)
}
zw.Reset(ioutil.Discard)
}(level)
}
}
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