add std::endian support if available

src/asfvideo.cpp

@@ -276,16 +276,14 @@ void AsfVideo::decodeBlock() {
       extendedStreamProperties();
     else if (tag->second == "Degradable_JPEG_Media")
       DegradableJPEGMedia();
-    else  // tag found but not processed
-    {
+    else {  // tag found but not processed
       // Make sure that the remaining size is non-zero, so that we won't
       // keep revisiting the same location in the file.
       const uint64_t remaining_size = objectHeader.getRemainingSize();
       Internal::enforce(remaining_size > 0, Exiv2::ErrorCode::kerCorruptedMetadata);
       io_->seekOrThrow(io_->tell() + remaining_size, BasicIo::beg, ErrorCode::kerFailedToReadImageData);
     }
-  } else  // tag not found
-  {
+  } else {  // tag not found
     // Make sure that the remaining size is non-zero, so that we won't keep
     // revisiting the same location in the file.
     const uint64_t remaining_size = objectHeader.getRemainingSize();

src/bmffimage.cpp

@@ -66,7 +66,13 @@ enum {
 
 // *****************************************************************************
 // class member definitions
-#ifdef EXV_ENABLE_BMFF
+#ifndef EXV_ENABLE_BMFF
+namespace Exiv2 {
+bool enableBMFF(bool) {
+  return false;
+}
+}  // namespace Exiv2
+#else
 namespace Exiv2 {
 static bool enabled = false;
 bool enableBMFF(bool enable) {
@@ -801,10 +807,4 @@ bool isBmffType(BasicIo& iIo, bool advance) {
   return matched;
 }
 }  // namespace Exiv2
-#else  // ifdef EXV_ENABLE_BMFF
-namespace Exiv2 {
-bool enableBMFF(bool) {
-  return false;
-}
-}  // namespace Exiv2
 #endif

src/image.cpp

@@ -51,6 +51,10 @@
 #include <limits>
 #include <set>
 
+#ifdef __cpp_lib_endian
+#include <bit>
+#endif
+
 // *****************************************************************************
 namespace {
 using namespace Exiv2;
@@ -168,7 +172,9 @@ bool Image::isPrintICC(uint16_t type, Exiv2::PrintStructureOption option) {
 }
 
 bool Image::isBigEndianPlatform() {
-#ifdef __LITTLE_ENDIAN__
+#ifdef __cpp_lib_endian
+  return std::endian::native == std::endian::big;
+#elif defined(__LITTLE_ENDIAN__)
   return false;
 #elif defined(__BIG_ENDIAN__)
   return true;
@@ -188,14 +194,19 @@ bool Image::isBigEndianPlatform() {
 #endif
 }
 bool Image::isLittleEndianPlatform() {
-#ifdef __LITTLE_ENDIAN__
+#ifdef __cpp_lib_endian
+  return std::endian::native == std::endian::little;
+#elif defined(__LITTLE_ENDIAN__)
   return true;
 #else
   return !isBigEndianPlatform();
 #endif
 }
 
 uint64_t Image::byteSwap(uint64_t value, bool bSwap) {
+#ifdef __cpp_lib_byteswap
+  return bSwap ? std::byteswap(value) : value;
+#else
   uint64_t result = 0;
   auto source_value = reinterpret_cast<byte*>(&value);
   auto destination_value = reinterpret_cast<byte*>(&result);
@@ -204,22 +215,31 @@ uint64_t Image::byteSwap(uint64_t value, bool bSwap) {
     destination_value[i] = source_value[8 - i - 1];
 
   return bSwap ? result : value;
+#endif
 }
 
 uint32_t Image::byteSwap(uint32_t value, bool bSwap) {
+#ifdef __cpp_lib_byteswap
+  return bSwap ? std::byteswap(value) : value;
+#else
   uint32_t result = 0;
   result |= (value & 0x000000FFU) << 24;
   result |= (value & 0x0000FF00U) << 8;
   result |= (value & 0x00FF0000U) >> 8;
   result |= (value & 0xFF000000U) >> 24;
   return bSwap ? result : value;
+#endif
 }
 
 uint16_t Image::byteSwap(uint16_t value, bool bSwap) {
+#ifdef __cpp_lib_byteswap
+  return bSwap ? std::byteswap(value) : value;
+#else
   uint16_t result = 0;
   result |= (value & 0x00FFU) << 8;
   result |= (value & 0xFF00U) >> 8;
   return bSwap ? result : value;
+#endif
 }
 
 uint16_t Image::byteSwap2(const DataBuf& buf, size_t offset, bool bSwap) {

src/pgfimage.cpp

@@ -28,12 +28,16 @@ const unsigned char pgfBlank[] = {
 
 namespace Exiv2 {
 static uint32_t byteSwap_(uint32_t value, bool bSwap) {
+#ifdef __cpp_lib_byteswap
+  return bSwap ? std::byteswap(value) : value;
+#else
   uint32_t result = 0;
   result |= (value & 0x000000FF) << 24;
   result |= (value & 0x0000FF00) << 8;
   result |= (value & 0x00FF0000) >> 8;
   result |= (value & 0xFF000000) >> 24;
   return bSwap ? result : value;
+#endif
 }
 
 static uint32_t byteSwap_(Exiv2::DataBuf& buf, size_t offset, bool bSwap) {

src/tags.cpp

@@ -52,15 +52,17 @@ bool TagVocabulary::operator==(const std::string& key) const {
 }
 
 // Unknown Tag
-static const TagInfo unknownTag{0xffff,
-                                "Unknown tag",
-                                N_("Unknown tag"),
-                                N_("Unknown tag"),
-                                IfdId::ifdIdNotSet,
-                                SectionId::sectionIdNotSet,
-                                asciiString,
-                                -1,
-                                printValue};
+static constexpr TagInfo unknownTag{
+    0xffff,
+    "Unknown tag",
+    N_("Unknown tag"),
+    N_("Unknown tag"),
+    IfdId::ifdIdNotSet,
+    SectionId::sectionIdNotSet,
+    asciiString,
+    -1,
+    printValue,
+};
 
 }  // namespace Exiv2::Internal
 
@@ -259,7 +261,7 @@ ExifKey::ExifKey(const std::string& key) : p_(std::make_unique<Impl>()) {
   p_->decomposeKey(key);
 }
 
-ExifKey::ExifKey(const ExifKey& rhs) : p_(std::make_unique<Impl>(*rhs.p_)) {
+ExifKey::ExifKey(const ExifKey& rhs) : Key(rhs), p_(std::make_unique<Impl>(*rhs.p_)) {
 }
 
 ExifKey::~ExifKey() = default;