direct initialize some structs

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/epsimage.cpp

@@ -759,33 +759,16 @@ void readWriteEpsMetadata(BasicIo& io, std::string& xmpPacket, NativePreviewList
       }
     }
     if (posEndPhotoshop != posEndEps) {
-      NativePreview nativePreview;
-      nativePreview.position_ = static_cast<long>(posBeginPhotoshop);
-      nativePreview.size_ = static_cast<uint32_t>(posEndPhotoshop - posBeginPhotoshop);
-      nativePreview.width_ = 0;
-      nativePreview.height_ = 0;
-      nativePreview.filter_ = "hex-irb";
-      nativePreview.mimeType_ = "image/jpeg";
+      auto sizePhotoshop = posEndPhotoshop - posBeginPhotoshop;
+      NativePreview nativePreview{posBeginPhotoshop, sizePhotoshop, 0, 0, "hex-irb", "image/jpeg"};
       nativePreviews.push_back(std::move(nativePreview));
     }
     if (sizeWmf != 0) {
-      NativePreview nativePreview;
-      nativePreview.position_ = static_cast<long>(posWmf);
-      nativePreview.size_ = sizeWmf;
-      nativePreview.width_ = 0;
-      nativePreview.height_ = 0;
-      nativePreview.filter_ = "";
-      nativePreview.mimeType_ = "image/x-wmf";
+      NativePreview nativePreview{posWmf, sizeWmf, 0, 0, "", "image/x-wmf"};
       nativePreviews.push_back(std::move(nativePreview));
     }
     if (sizeTiff != 0) {
-      NativePreview nativePreview;
-      nativePreview.position_ = static_cast<long>(posTiff);
-      nativePreview.size_ = sizeTiff;
-      nativePreview.width_ = 0;
-      nativePreview.height_ = 0;
-      nativePreview.filter_ = "";
-      nativePreview.mimeType_ = "image/tiff";
+      NativePreview nativePreview{posTiff, sizeTiff, 0, 0, "", "image/tiff"};
       nativePreviews.push_back(std::move(nativePreview));
     }
   } else {

src/psdimage.cpp

@@ -292,13 +292,12 @@ void PsdImage::readResourceBlock(uint16_t resourceId, uint32_t resourceSize) {
         if (io_->error() || io_->eof())
           throw Error(ErrorCode::kerFailedToReadImageData);
 
-        if (format == 1) {
+        // unsupported format of native preview
+        if (format != 1)
+          break;
         nativePreview.filter_ = "";
         nativePreview.mimeType_ = "image/jpeg";
         nativePreviews_.push_back(std::move(nativePreview));
-        } else {
-          // unsupported format of native preview
-        }
       }
       break;
     }

src/xmp.cpp

@@ -422,7 +422,7 @@ Xmpdatum& XmpData::operator[](const std::string& key) {
   XmpKey xmpKey(key);
   auto pos = findKey(xmpKey);
   if (pos == end()) {
-    xmpMetadata_.push_back(Xmpdatum(xmpKey));
+    xmpMetadata_.emplace_back(xmpKey);
     return xmpMetadata_.back();
   }
   return *pos;