JXR: Fixed image reading on sequential devices

The following changes are done:
- Fixed an error when copying image from sequential device
- Return error when the image exceed 4GB size on writing*
- Enabled JXR tests

(*) Note that when writing an image larger than 4GiB, the JXRLib does not give any error but the resulting saved image id wrong.

.kde-ci.yml

@@ -7,3 +7,4 @@ Dependencies:
 Options:
   test-before-installing: True
   require-passing-tests-on: [ 'Linux', 'FreeBSD', 'Windows' ]
+  cmake-options: "-DKIMAGEFORMATS_JXR=ON"

README.md

@@ -117,7 +117,7 @@ plugin ('n/a' means no limit, i.e. the limit depends on the format encoding).
 - HDR: n/a (large image)
 - HEIF: n/a
 - JXL: 65,535 x 65,535 pixels, in any case no larger than 256 megapixels
-- JXR: n/a
+- JXR: n/a, in any case no larger than 4 GB
 - PCX: 65,535 x 65,535 pixels
 - PFM: n/a (large image)
 - PIC: 65,535 x 65,535 pixels

src/imageformats/jxr.cpp

@@ -484,11 +484,13 @@ public:
                 qi = qi.convertToFormat(alpha ? QImage::Format_RGBA8888 : QImage::Format_RGB888);
             }
 #ifndef JXR_DENY_FLOAT_IMAGE
-        } else if(qi.format() == QImage::Format_RGBA16FPx4 ||
+            // clang-format off
-                  qi.format() == QImage::Format_RGBX16FPx4 ||
+        } else if (qi.format() == QImage::Format_RGBA16FPx4 ||
-                  qi.format() == QImage::Format_RGBA32FPx4 ||
+                   qi.format() == QImage::Format_RGBX16FPx4 ||
-                  qi.format() == QImage::Format_RGBA32FPx4_Premultiplied ||
+                   qi.format() == QImage::Format_RGBA32FPx4 ||
-                  qi.format() == QImage::Format_RGBX32FPx4) {
+                   qi.format() == QImage::Format_RGBA32FPx4_Premultiplied ||
+                   qi.format() == QImage::Format_RGBX32FPx4) {
+            // clang-format on
             auto cs = qi.colorSpace();
             if (cs.isValid() && cs.transferFunction() != QColorSpace::TransferFunction::Linear) {
                 qi = qi.convertedToColorSpace(QColorSpace(QColorSpace::SRgbLinear));
@@ -670,9 +672,12 @@ private:
             return false;
         }
         QByteArray buff(32768 * 4, char());
-        for (; !source->atEnd();) {
+        for (;;) {
             auto read = source->read(buff.data(), buff.size());
-            if (read < 1) {
+            if (read == 0) {
+                break;
+            }
+            if (read < 0) {
                 return false;
             }
             if (target->write(buff.data(), read) != read) {
@@ -868,7 +873,7 @@ bool JXRHandler::read(QImage *outImage)
                     line[x + 3] = hasAlpha ? std::clamp(line[x + 3], float(0), float(1)) : float(1);
             }
         }
-        if(!img.colorSpace().isValid()) {
+        if (!img.colorSpace().isValid()) {
             img.setColorSpace(QColorSpace(QColorSpace::SRgbLinear));
         }
     }
@@ -880,6 +885,13 @@ bool JXRHandler::read(QImage *outImage)
 
 bool JXRHandler::write(const QImage &image)
 {
+    // JXR is stored in a TIFF V6 container that is limited to 4GiB. The size
+    // is limited to 4GB to leave room for IFDs, Metadata, etc...
+    if (qint64(image.sizeInBytes()) > 4000000000ll) {
+        qCWarning(LOG_JXRPLUGIN) << "JXRHandler::write() image too large: the image cannot exceed 4GB.";
+        return false;
+    }
+
     if (!d->initForWriting()) {
         return false;
     }
@@ -1064,11 +1076,6 @@ bool JXRHandler::canRead(QIODevice *device)
         return false;
     }
 
-    // Some tests on sequential devices fail: I reject them for now
-    if (device->isSequential()) {
-        return false;
-    }
-
     // JPEG XR image data is stored in TIFF-like container format (II and 0xBC01 version)
     if (device->peek(4) == QByteArray::fromRawData("\x49\x49\xbc\x01", 4)) {
         return true;