Description
What version of Go are you using (go version)?
$ go version go version go1.14.4 linux/amd64
Does this issue reproduce with the latest release?
With last master branch.
What operating system and processor architecture are you using (go env)?
go env Output
$ go env GO111MODULE="on" GOARCH="amd64" GOBIN="/home/x/go/bin" GOCACHE="/home/x/.cache/go-build" GOENV="/home/x/.config/go/env" GOEXE="" GOFLAGS="" GOHOSTARCH="amd64" GOHOSTOS="linux" GOOS="linux" GOPATH="/home/x/go" GOPROXY="https://proxy.golang.org,direct" GOROOT="/usr/lib/go" GOSUMDB="sum.golang.org" GOTMPDIR="" GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64" GCCGO="gccgo" AR="ar" CC="gcc" CXX="g++" CGO_ENABLED="1" CGO_CFLAGS="-g -O2" CGO_CPPFLAGS="" CGO_CXXFLAGS="-g -O2" CGO_FFLAGS="-g -O2" CGO_LDFLAGS="-g -O2" PKG_CONFIG="pkg-config" GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build670162663=/tmp/go-build -gno-record-gcc-switches"
What did you do?
Tiff file used to get an error debug_26428.zip (compressed with zip, extract it for usage). Length of tiff file is: 26428 bytes.
I've created test cases that can be used for tiff and ccitt package. Because it is called with tiff.Decode(), but error is in ccitt.decodeEOL().
tiff
Copy extracted tiff to root testdata and copy this test case to tiff.reader_test.go
func TestTiffDecodeOfCCITTEndOfLine(t *testing.T) {
b, err := ioutil.ReadFile("../testdata/debug_26428.tiff")
if err != nil {
t.Fatalf("Read File: %v", err)
}
if _, err = Decode(bytes.NewReader(b)); err != nil {
t.Errorf("Shouldn't error, but got err: %v", err)
}
}Output:
--- FAIL: TestTiffDecodeOfCCITTEndOfLine (0.02s)
reader_test.go:68: Shouldn't error, but got err: ccitt: missing End-of-Line
ccitt
Copy extracted tiff to ccitt testdata and copy this test to ccitt.reader_test.go
Data taken from actual debugging for this file, when called with tiff.Decode().
func TestReadEndOfLineError(t *testing.T) {
f, err := os.Open("testdata/debug_26428.tiff")
if err != nil {
t.Fatalf("Open: %v", err)
}
defer f.Close()
const width, height = 2481, 3508
opts := &Options{
Align: false,
Invert: true,
}
offset := 160
n := 26268
if _, err := ioutil.ReadAll(NewReader(io.NewSectionReader(f, int64(offset), int64(n)), MSB, Group4, width, height, opts)); err != nil {
t.Fatalf("Shouldn't error but got error: %v", err)
}
}Output:
--- FAIL: TestReadEndOfLineError (0.03s)
reader_test.go:411: Shouldn't error but got error: ccitt: missing End-of-Line
What works for this case
I'm not even remotely expert on specs for TIFF and ccitt, but I've changed last return from return errMissingEOL to return nil and I'm getting correct image and everything works fine and tried in many files (mostly all scanned textual with images, and all B/W) and I've see no problems with this fix/hack.
// decodeEOL decodes the 12-bit EOL code 0000_0000_0001.
func decodeEOL(b *bitReader) error {
nBitsRead, bitsRead := uint32(0), uint64(0)
for {
bit, err := b.nextBit()
if err != nil {
if err == io.EOF {
err = errMissingEOL
}
return err
}
bitsRead |= bit << (63 - nBitsRead)
nBitsRead++
if nBitsRead < 12 {
if bit&1 == 0 {
continue
}
} else if bit&1 != 0 {
return nil
}
// Unread the bits we've read, then return errMissingEOL.
b.bits = (b.bits >> nBitsRead) | bitsRead
b.nBits += nBitsRead
// Changing from errMissingEOL to nil works for this case
// return errMissingEOL
return nil
}
}Request
Can anybody see in TIFF provided, run this tests, maybe do better "fix". Because with this applied ccitt test TestRead fails with output:
--- FAIL: TestRead (0.00s)
reader_test.go:437: AutoDetectHeight produced different output.
Thanks