...
Run Format

Source file src/image/jpeg/reader_test.go

Documentation: image/jpeg

  // 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 jpeg
  
  import (
  	"bytes"
  	"fmt"
  	"image"
  	"image/color"
  	"io"
  	"io/ioutil"
  	"math/rand"
  	"os"
  	"strings"
  	"testing"
  	"time"
  )
  
  // TestDecodeProgressive tests that decoding the baseline and progressive
  // versions of the same image result in exactly the same pixel data, in YCbCr
  // space for color images, and Y space for grayscale images.
  func TestDecodeProgressive(t *testing.T) {
  	testCases := []string{
  		"../testdata/video-001",
  		"../testdata/video-001.q50.410",
  		"../testdata/video-001.q50.411",
  		"../testdata/video-001.q50.420",
  		"../testdata/video-001.q50.422",
  		"../testdata/video-001.q50.440",
  		"../testdata/video-001.q50.444",
  		"../testdata/video-005.gray.q50",
  		"../testdata/video-005.gray.q50.2x2",
  		"../testdata/video-001.separate.dc.progression",
  	}
  	for _, tc := range testCases {
  		m0, err := decodeFile(tc + ".jpeg")
  		if err != nil {
  			t.Errorf("%s: %v", tc+".jpeg", err)
  			continue
  		}
  		m1, err := decodeFile(tc + ".progressive.jpeg")
  		if err != nil {
  			t.Errorf("%s: %v", tc+".progressive.jpeg", err)
  			continue
  		}
  		if m0.Bounds() != m1.Bounds() {
  			t.Errorf("%s: bounds differ: %v and %v", tc, m0.Bounds(), m1.Bounds())
  			continue
  		}
  		// All of the video-*.jpeg files are 150x103.
  		if m0.Bounds() != image.Rect(0, 0, 150, 103) {
  			t.Errorf("%s: bad bounds: %v", tc, m0.Bounds())
  			continue
  		}
  
  		switch m0 := m0.(type) {
  		case *image.YCbCr:
  			m1 := m1.(*image.YCbCr)
  			if err := check(m0.Bounds(), m0.Y, m1.Y, m0.YStride, m1.YStride); err != nil {
  				t.Errorf("%s (Y): %v", tc, err)
  				continue
  			}
  			if err := check(m0.Bounds(), m0.Cb, m1.Cb, m0.CStride, m1.CStride); err != nil {
  				t.Errorf("%s (Cb): %v", tc, err)
  				continue
  			}
  			if err := check(m0.Bounds(), m0.Cr, m1.Cr, m0.CStride, m1.CStride); err != nil {
  				t.Errorf("%s (Cr): %v", tc, err)
  				continue
  			}
  		case *image.Gray:
  			m1 := m1.(*image.Gray)
  			if err := check(m0.Bounds(), m0.Pix, m1.Pix, m0.Stride, m1.Stride); err != nil {
  				t.Errorf("%s: %v", tc, err)
  				continue
  			}
  		default:
  			t.Errorf("%s: unexpected image type %T", tc, m0)
  			continue
  		}
  	}
  }
  
  func decodeFile(filename string) (image.Image, error) {
  	f, err := os.Open(filename)
  	if err != nil {
  		return nil, err
  	}
  	defer f.Close()
  	return Decode(f)
  }
  
  type eofReader struct {
  	data     []byte // deliver from Read without EOF
  	dataEOF  []byte // then deliver from Read with EOF on last chunk
  	lenAtEOF int
  }
  
  func (r *eofReader) Read(b []byte) (n int, err error) {
  	if len(r.data) > 0 {
  		n = copy(b, r.data)
  		r.data = r.data[n:]
  	} else {
  		n = copy(b, r.dataEOF)
  		r.dataEOF = r.dataEOF[n:]
  		if len(r.dataEOF) == 0 {
  			err = io.EOF
  			if r.lenAtEOF == -1 {
  				r.lenAtEOF = n
  			}
  		}
  	}
  	return
  }
  
  func TestDecodeEOF(t *testing.T) {
  	// Check that if reader returns final data and EOF at same time, jpeg handles it.
  	data, err := ioutil.ReadFile("../testdata/video-001.jpeg")
  	if err != nil {
  		t.Fatal(err)
  	}
  
  	n := len(data)
  	for i := 0; i < n; {
  		r := &eofReader{data[:n-i], data[n-i:], -1}
  		_, err := Decode(r)
  		if err != nil {
  			t.Errorf("Decode with Read() = %d, EOF: %v", r.lenAtEOF, err)
  		}
  		if i == 0 {
  			i = 1
  		} else {
  			i *= 2
  		}
  	}
  }
  
  // check checks that the two pix data are equal, within the given bounds.
  func check(bounds image.Rectangle, pix0, pix1 []byte, stride0, stride1 int) error {
  	if stride0 <= 0 || stride0%8 != 0 {
  		return fmt.Errorf("bad stride %d", stride0)
  	}
  	if stride1 <= 0 || stride1%8 != 0 {
  		return fmt.Errorf("bad stride %d", stride1)
  	}
  	// Compare the two pix data, one 8x8 block at a time.
  	for y := 0; y < len(pix0)/stride0 && y < len(pix1)/stride1; y += 8 {
  		for x := 0; x < stride0 && x < stride1; x += 8 {
  			if x >= bounds.Max.X || y >= bounds.Max.Y {
  				// We don't care if the two pix data differ if the 8x8 block is
  				// entirely outside of the image's bounds. For example, this can
  				// occur with a 4:2:0 chroma subsampling and a 1x1 image. Baseline
  				// decoding works on the one 16x16 MCU as a whole; progressive
  				// decoding's first pass works on that 16x16 MCU as a whole but
  				// refinement passes only process one 8x8 block within the MCU.
  				continue
  			}
  
  			for j := 0; j < 8; j++ {
  				for i := 0; i < 8; i++ {
  					index0 := (y+j)*stride0 + (x + i)
  					index1 := (y+j)*stride1 + (x + i)
  					if pix0[index0] != pix1[index1] {
  						return fmt.Errorf("blocks at (%d, %d) differ:\n%sand\n%s", x, y,
  							pixString(pix0, stride0, x, y),
  							pixString(pix1, stride1, x, y),
  						)
  					}
  				}
  			}
  		}
  	}
  	return nil
  }
  
  func pixString(pix []byte, stride, x, y int) string {
  	s := bytes.NewBuffer(nil)
  	for j := 0; j < 8; j++ {
  		fmt.Fprintf(s, "\t")
  		for i := 0; i < 8; i++ {
  			fmt.Fprintf(s, "%02x ", pix[(y+j)*stride+(x+i)])
  		}
  		fmt.Fprintf(s, "\n")
  	}
  	return s.String()
  }
  
  func TestTruncatedSOSDataDoesntPanic(t *testing.T) {
  	b, err := ioutil.ReadFile("../testdata/video-005.gray.q50.jpeg")
  	if err != nil {
  		t.Fatal(err)
  	}
  	sosMarker := []byte{0xff, 0xda}
  	i := bytes.Index(b, sosMarker)
  	if i < 0 {
  		t.Fatal("SOS marker not found")
  	}
  	i += len(sosMarker)
  	j := i + 10
  	if j > len(b) {
  		j = len(b)
  	}
  	for ; i < j; i++ {
  		Decode(bytes.NewReader(b[:i]))
  	}
  }
  
  func TestLargeImageWithShortData(t *testing.T) {
  	// This input is an invalid JPEG image, based on the fuzzer-generated image
  	// in issue 10413. It is only 504 bytes, and shouldn't take long for Decode
  	// to return an error. The Start Of Frame marker gives the image dimensions
  	// as 8192 wide and 8192 high, so even if an unreadByteStuffedByte bug
  	// doesn't technically lead to an infinite loop, such a bug can still cause
  	// an unreasonably long loop for such a short input.
  	const input = "" +
  		"\xff\xd8\xff\xe0\x00\x10\x4a\x46\x49\x46\x00\x01\x01\x00\x00\x01" +
  		"\x00\x01\x00\x00\xff\xdb\x00\x43\x00\x10\x0b\x0c\x0e\x0c\x0a\x10" +
  		"\x0e\x89\x0e\x12\x11\x10\x13\x18\xff\xd8\xff\xe0\x00\x10\x4a\x46" +
  		"\x49\x46\x00\x01\x01\x00\x00\x01\x00\x01\x00\x00\xff\xdb\x00\x43" +
  		"\x00\x10\x0b\x0c\x0e\x0c\x0a\x10\x0e\x0d\x0e\x12\x11\x10\x13\x18" +
  		"\x28\x1a\x18\x16\x16\x18\x31\x23\x25\x1d\x28\x3a\x33\x3d\x3c\x39" +
  		"\x33\x38\x37\x40\x48\x5c\x4e\x40\x44\x57\x45\x37\x38\x50\x6d\x51" +
  		"\x57\x5f\x62\x67\x68\x67\x3e\x4d\x71\x79\x70\x64\x78\x5c\x65\x67" +
  		"\x63\xff\xc0\x00\x0b\x08\x20\x00\x20\x00\x01\x01\x11\x00\xff\xc4" +
  		"\x00\x1f\x00\x00\x01\x05\x01\x01\x01\x01\x01\x01\x00\x00\x00\x00" +
  		"\x00\x00\x00\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\xff" +
  		"\xc4\x00\xb5\x10\x00\x02\x01\x03\x03\x02\x04\x03\x05\x05\x04\x04" +
  		"\x00\x00\x01\x7d\x01\x02\x03\x00\x04\x11\x05\x12\x21\x31\x01\x06" +
  		"\x13\x51\x61\x07\x22\x71\x14\x32\x81\x91\xa1\x08\x23\xd8\xff\xdd" +
  		"\x42\xb1\xc1\x15\x52\xd1\xf0\x24\x33\x62\x72\x82\x09\x0a\x16\x17" +
  		"\x18\x19\x1a\x25\x26\x27\x28\x29\x2a\x34\x35\x36\x37\x38\x39\x3a" +
  		"\x43\x44\x45\x46\x47\x48\x49\x4a\x53\x54\x55\x56\x57\x58\x59\x5a" +
  		"\x00\x63\x64\x65\x66\x67\x68\x69\x6a\x73\x74\x75\x76\x77\x78\x79" +
  		"\x7a\x83\x84\x85\x86\x87\x88\x89\x8a\x92\x93\x94\x95\x96\x97\x98" +
  		"\x99\x9a\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xb2\xb3\xb4\xb5\xb6" +
  		"\xb7\xb8\xb9\xba\xc2\xc3\xc4\xc5\xc6\xc7\xff\xd8\xff\xe0\x00\x10" +
  		"\x4a\x46\x49\x46\x00\x01\x01\x00\x00\x01\x00\x01\x00\x00\xff\xdb" +
  		"\x00\x43\x00\x10\x0b\x0c\x0e\x0c\x0a\x10\x0e\x0d\x0e\x12\x11\x10" +
  		"\x13\x18\x28\x1a\x18\x16\x16\x18\x31\x23\x25\x1d\xc8\xc9\xca\xd2" +
  		"\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8" +
  		"\xe9\xea\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xff\xda\x00\x08" +
  		"\x01\x01\x00\x00\x3f\x00\xb9\xeb\x50\xb0\xdb\xc8\xa8\xe4\x63\x80" +
  		"\xdd\x31\xd6\x9d\xbb\xf2\xc5\x42\x1f\x6c\x6f\xf4\x34\xdd\x3c\xfc" +
  		"\xac\xe7\x3d\x80\xa9\xcc\x87\x34\xb3\x37\xfa\x2b\x9f\x6a\xad\x63" +
  		"\x20\x36\x9f\x78\x64\x75\xe6\xab\x7d\xb2\xde\x29\x70\xd3\x20\x27" +
  		"\xde\xaf\xa4\xf0\xca\x9f\x24\xa8\xdf\x46\xa8\x24\x84\x96\xe3\x77" +
  		"\xf9\x2e\xe0\x0a\x62\x7f\xdf\xd9"
  	c := make(chan error, 1)
  	go func() {
  		_, err := Decode(strings.NewReader(input))
  		c <- err
  	}()
  	select {
  	case err := <-c:
  		if err == nil {
  			t.Fatalf("got nil error, want non-nil")
  		}
  	case <-time.After(3 * time.Second):
  		t.Fatalf("timed out")
  	}
  }
  
  func TestExtraneousData(t *testing.T) {
  	// Encode a 1x1 red image.
  	src := image.NewRGBA(image.Rect(0, 0, 1, 1))
  	src.Set(0, 0, color.RGBA{0xff, 0x00, 0x00, 0xff})
  	buf := new(bytes.Buffer)
  	if err := Encode(buf, src, nil); err != nil {
  		t.Fatalf("encode: %v", err)
  	}
  	enc := buf.String()
  	// Sanity check that the encoded JPEG is long enough, that it ends in a
  	// "\xff\xd9" EOI marker, and that it contains a "\xff\xda" SOS marker
  	// somewhere in the final 64 bytes.
  	if len(enc) < 64 {
  		t.Fatalf("encoded JPEG is too short: %d bytes", len(enc))
  	}
  	if got, want := enc[len(enc)-2:], "\xff\xd9"; got != want {
  		t.Fatalf("encoded JPEG ends with %q, want %q", got, want)
  	}
  	if s := enc[len(enc)-64:]; !strings.Contains(s, "\xff\xda") {
  		t.Fatalf("encoded JPEG does not contain a SOS marker (ff da) near the end: % x", s)
  	}
  	// Test that adding some random junk between the SOS marker and the
  	// EOI marker does not affect the decoding.
  	rnd := rand.New(rand.NewSource(1))
  	for i, nerr := 0, 0; i < 1000 && nerr < 10; i++ {
  		buf.Reset()
  		// Write all but the trailing "\xff\xd9" EOI marker.
  		buf.WriteString(enc[:len(enc)-2])
  		// Write some random extraneous data.
  		for n := rnd.Intn(10); n > 0; n-- {
  			if x := byte(rnd.Intn(256)); x != 0xff {
  				buf.WriteByte(x)
  			} else {
  				// The JPEG format escapes a SOS 0xff data byte as "\xff\x00".
  				buf.WriteString("\xff\x00")
  			}
  		}
  		// Write the "\xff\xd9" EOI marker.
  		buf.WriteString("\xff\xd9")
  
  		// Check that we can still decode the resultant image.
  		got, err := Decode(buf)
  		if err != nil {
  			t.Errorf("could not decode image #%d: %v", i, err)
  			nerr++
  			continue
  		}
  		if got.Bounds() != src.Bounds() {
  			t.Errorf("image #%d, bounds differ: %v and %v", i, got.Bounds(), src.Bounds())
  			nerr++
  			continue
  		}
  		if averageDelta(got, src) > 2<<8 {
  			t.Errorf("image #%d changed too much after a round trip", i)
  			nerr++
  			continue
  		}
  	}
  }
  
  func benchmarkDecode(b *testing.B, filename string) {
  	b.StopTimer()
  	data, err := ioutil.ReadFile(filename)
  	if err != nil {
  		b.Fatal(err)
  	}
  	cfg, err := DecodeConfig(bytes.NewReader(data))
  	if err != nil {
  		b.Fatal(err)
  	}
  	b.SetBytes(int64(cfg.Width * cfg.Height * 4))
  	b.StartTimer()
  	for i := 0; i < b.N; i++ {
  		Decode(bytes.NewReader(data))
  	}
  }
  
  func BenchmarkDecodeBaseline(b *testing.B) {
  	benchmarkDecode(b, "../testdata/video-001.jpeg")
  }
  
  func BenchmarkDecodeProgressive(b *testing.B) {
  	benchmarkDecode(b, "../testdata/video-001.progressive.jpeg")
  }
  

View as plain text