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-rw-r--r--src/compress/flate/deflate_test.go984
1 files changed, 984 insertions, 0 deletions
diff --git a/src/compress/flate/deflate_test.go b/src/compress/flate/deflate_test.go
new file mode 100644
index 0000000..ff56712
--- /dev/null
+++ b/src/compress/flate/deflate_test.go
@@ -0,0 +1,984 @@
+// 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"
+ "math/rand"
+ "os"
+ "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(io.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 = io.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 := io.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 := os.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 := io.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(io.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(io.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(io.Discard)
+
+ wref, err := NewWriter(io.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)
+ }
+ }
+
+ levels := []int{0, 1, 2, 5, 9}
+ for _, level := range levels {
+ t.Run(fmt.Sprint(level), func(t *testing.T) {
+ testResetOutput(t, level, nil)
+ })
+ }
+
+ t.Run("dict", func(t *testing.T) {
+ for _, level := range levels {
+ t.Run(fmt.Sprint(level), func(t *testing.T) {
+ testResetOutput(t, level, nil)
+ })
+ }
+ })
+}
+
+func testResetOutput(t *testing.T, level int, dict []byte) {
+ writeData := func(w *Writer) {
+ msg := []byte("now is the time for all good gophers")
+ w.Write(msg)
+ w.Flush()
+
+ hello := []byte("hello world")
+ for i := 0; i < 1024; i++ {
+ w.Write(hello)
+ }
+
+ fill := bytes.Repeat([]byte("x"), 65000)
+ w.Write(fill)
+ }
+
+ buf := new(bytes.Buffer)
+ var w *Writer
+ var err error
+ if dict == nil {
+ w, err = NewWriter(buf, level)
+ } else {
+ w, err = NewWriterDict(buf, level, dict)
+ }
+ if err != nil {
+ t.Fatalf("NewWriter: %v", err)
+ }
+
+ writeData(w)
+ w.Close()
+ out1 := buf.Bytes()
+
+ buf2 := new(bytes.Buffer)
+ w.Reset(buf2)
+ writeData(w)
+ 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 := io.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 := os.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 := io.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 TestBestSpeedShiftOffsets(t *testing.T) {
+ // Test if shiftoffsets properly preserves matches and resets out-of-range matches
+ // seen in https://github.com/golang/go/issues/4142
+ enc := newDeflateFast()
+
+ // testData may not generate internal matches.
+ testData := make([]byte, 32)
+ rng := rand.New(rand.NewSource(0))
+ for i := range testData {
+ testData[i] = byte(rng.Uint32())
+ }
+
+ // Encode the testdata with clean state.
+ // Second part should pick up matches from the first block.
+ wantFirstTokens := len(enc.encode(nil, testData))
+ wantSecondTokens := len(enc.encode(nil, testData))
+
+ if wantFirstTokens <= wantSecondTokens {
+ t.Fatalf("test needs matches between inputs to be generated")
+ }
+ // Forward the current indicator to before wraparound.
+ enc.cur = bufferReset - int32(len(testData))
+
+ // Part 1 before wrap, should match clean state.
+ got := len(enc.encode(nil, testData))
+ if wantFirstTokens != got {
+ t.Errorf("got %d, want %d tokens", got, wantFirstTokens)
+ }
+
+ // Verify we are about to wrap.
+ if enc.cur != bufferReset {
+ t.Errorf("got %d, want e.cur to be at bufferReset (%d)", enc.cur, bufferReset)
+ }
+
+ // Part 2 should match clean state as well even if wrapped.
+ got = len(enc.encode(nil, testData))
+ if wantSecondTokens != got {
+ t.Errorf("got %d, want %d token", got, wantSecondTokens)
+ }
+
+ // Verify that we wrapped.
+ if enc.cur >= bufferReset {
+ t.Errorf("want e.cur to be < bufferReset (%d), got %d", bufferReset, enc.cur)
+ }
+
+ // Forward the current buffer, leaving the matches at the bottom.
+ enc.cur = bufferReset
+ enc.shiftOffsets()
+
+ // Ensure that no matches were picked up.
+ got = len(enc.encode(nil, testData))
+ if wantFirstTokens != got {
+ t.Errorf("got %d, want %d tokens", got, wantFirstTokens)
+ }
+}
+
+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(io.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(io.Discard)
+ }(level)
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 07:24:36 +0000