1 files changed, 270 insertions, 0 deletions
diff --git a/src/image/jpeg/reader_test.go b/src/image/jpeg/reader_test.go
new file mode 100644
index 000000000..4de2e8ee7
--- /dev/null
+++ b/src/image/jpeg/reader_test.go
@@ -0,0 +1,270 @@
+// 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"
+)
+
+// 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.q50.420",
+		"../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 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")
+}