remove endian handling

There's std::endian now.

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

include/exiv2/config.h

@@ -31,20 +31,6 @@
 #endif
 #endif
 
-#ifndef __LITTLE_ENDIAN__
-#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__)
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-#define __LITTLE_ENDIAN__ 1
-#endif
-#endif
-#endif
-
-#ifndef __LITTLE_ENDIAN__
-#if defined(_WIN32) || defined(__CYGWIN__)
-#define __LITTLE_ENDIAN__ 1
-#endif
-#endif
-
 /*
   If you're using Solaris and the Solaris Studio compiler
   you must -library=stdcxx4 along with these inclusions below

include/exiv2/image.hpp

@@ -301,16 +301,6 @@ class EXIV2API Image {
   void printIFDStructure(BasicIo& io, std::ostream& out, Exiv2::PrintStructureOption option, size_t start, bool bSwap,
                          char c, size_t depth);
 
-  /*!
-    @brief is the host platform bigEndian
-   */
-  static bool isBigEndianPlatform();
-
-  /*!
-    @brief is the host platform littleEndian
-   */
-  static bool isLittleEndianPlatform();
-
   static bool isStringType(uint16_t type);
   static bool isShortType(uint16_t type);
   static bool isLongType(uint16_t type);

include/exiv2/pgfimage.hpp

@@ -55,7 +55,6 @@ class EXIV2API PgfImage : public Image {
   //@}
 
  private:
-  bool bSwap_;  // true for bigEndian hardware, else false
   /*!
     @brief Provides the main implementation of writeMetadata() by
           writing all buffered metadata to the provided BasicIo.
@@ -71,7 +70,6 @@ class EXIV2API PgfImage : public Image {
   //! Read header structure.
   DataBuf readPgfHeaderStructure(BasicIo& iIo, uint32_t& width, uint32_t& height) const;
   //@}
-
 };  // class PgfImage
 
 // *****************************************************************************

src/asfvideo.cpp

@@ -2,6 +2,7 @@
 // included header files
 #include "asfvideo.hpp"
 
+#include <bit>
 #include <cstring>
 #include <iostream>
 #include <sstream>
@@ -55,11 +56,9 @@ AsfVideo::GUIDTag::GUIDTag(const uint8_t* bytes) {
   std::copy_n(bytes + DWORD, WORD, reinterpret_cast<uint8_t*>(&data2_));
   std::copy_n(bytes + DWORD + WORD, WORD, reinterpret_cast<uint8_t*>(&data3_));
   std::copy(bytes + QWORD, bytes + 2 * QWORD, data4_.begin());
-  if (isBigEndianPlatform()) {
-    data1_ = byteSwap(data1_, true);
-    data2_ = byteSwap(data2_, true);
-    data3_ = byteSwap(data3_, true);
-  }
+  data1_ = byteSwap(data1_, std::endian::native == std::endian::big);
+  data2_ = byteSwap(data2_, std::endian::native == std::endian::big);
+  data3_ = byteSwap(data3_, std::endian::native == std::endian::big);
 }
 
 std::string AsfVideo::GUIDTag::to_string() {

src/bmffimage.cpp

@@ -21,6 +21,7 @@
 #endif
 
 // + standard includes
+#include <bit>
 #include <cinttypes>
 #include <cstdio>
 #include <cstring>
@@ -91,7 +92,7 @@ BmffImage::BmffImage(BasicIo::UniquePtr io, bool /* create */) :
 std::string BmffImage::toAscii(uint32_t n) {
   const auto p = reinterpret_cast<const char*>(&n);
   std::string result(p, p + 4);
-  if (!isBigEndianPlatform())
+  if constexpr (std::endian::native == std::endian::little)
     std::reverse(result.begin(), result.end());
   // show 0 as _
   std::replace(result.begin(), result.end(), '\0', '_');

src/image.cpp

@@ -171,38 +171,6 @@ bool Image::isPrintICC(uint16_t type, Exiv2::PrintStructureOption option) {
   return type == 0x8773 && option == kpsIccProfile;
 }
 
-bool Image::isBigEndianPlatform() {
-#ifdef __cpp_lib_endian
-  return std::endian::native == std::endian::big;
-#elif defined(__LITTLE_ENDIAN__)
-  return false;
-#elif defined(__BIG_ENDIAN__)
-  return true;
-#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__)
-#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-  return true;
-#else
-  return false;
-#endif
-#else
-  union {
-    uint32_t i;
-    char c[4];
-  } e = {0x01000000};
-
-  return e.c[0] != 0;
-#endif
-}
-bool Image::isLittleEndianPlatform() {
-#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;
@@ -548,7 +516,8 @@ void Image::printTiffStructure(BasicIo& io, std::ostream& out, Exiv2::PrintStruc
     // read header (we already know for certain that we have a Tiff file)
     io.readOrThrow(dir.data(), 8, ErrorCode::kerCorruptedMetadata);
     auto c = dir.read_uint8(0);
-    bool bSwap = (c == 'M' && isLittleEndianPlatform()) || (c == 'I' && isBigEndianPlatform());
+    bool bSwap = (c == 'M' && std::endian::native == std::endian::little) ||
+                 (c == 'I' && std::endian::native == std::endian::big);
     size_t start = byteSwap4(dir, 4, bSwap);
     printIFDStructure(io, out, option, start + offset, bSwap, c, depth);
   }

src/jp2image.cpp

@@ -18,6 +18,7 @@
 
 #include <algorithm>
 #include <array>
+#include <bit>
 #include <iostream>
 
 namespace Exiv2 {
@@ -100,7 +101,7 @@ Jp2Image::Jp2Image(BasicIo::UniquePtr io, bool create) : Image(ImageType::jp2, m
 // Obtains the ascii version from the box.type
 std::string Jp2Image::toAscii(uint32_t n) {
   const auto p = reinterpret_cast<const char*>(&n);
-  if (isBigEndianPlatform())
+  if constexpr (std::endian::native == std::endian::big)
     return std::string(p, p + 4);
   std::string result(p, p + 4);
   std::reverse(result.begin(), result.end());

src/pgfimage.cpp

@@ -10,6 +10,7 @@
 #include "futils.hpp"
 #include "image.hpp"
 
+#include <bit>
 #include <iostream>
 
 // Signature from front of PGF file
@@ -54,7 +55,7 @@ static uint32_t byteSwap_(Exiv2::DataBuf& buf, size_t offset, bool bSwap) {
 }
 
 PgfImage::PgfImage(BasicIo::UniquePtr io, bool create) :
-    Image(ImageType::pgf, mdExif | mdIptc | mdXmp | mdComment, std::move(io)), bSwap_(isBigEndianPlatform()) {
+    Image(ImageType::pgf, mdExif | mdIptc | mdXmp | mdComment, std::move(io)) {
   if (create && io_->open() == 0) {
 #ifdef EXIV2_DEBUG_MESSAGES
     std::cerr << "Exiv2::PgfImage:: Creating PGF image to memory\n";
@@ -184,7 +185,7 @@ void PgfImage::doWriteMetadata(BasicIo& outIo) {
   auto newHeaderSize = static_cast<uint32_t>(header.size() + imgSize);
   DataBuf buffer(4);
   std::copy_n(&newHeaderSize, sizeof(uint32_t), buffer.data());
-  byteSwap_(buffer, 0, bSwap_);
+  byteSwap_(buffer, 0, std::endian::native == std::endian::big);
   if (outIo.write(buffer.c_data(), 4) != 4)
     throw Error(ErrorCode::kerImageWriteFailed);
 
@@ -243,7 +244,7 @@ size_t PgfImage::readPgfHeaderSize(BasicIo& iIo) const {
   if (bufRead != buffer.size())
     throw Error(ErrorCode::kerInputDataReadFailed);
 
-  auto headerSize = static_cast<size_t>(byteSwap_(buffer, 0, bSwap_));
+  auto headerSize = static_cast<size_t>(byteSwap_(buffer, 0, std::endian::native == std::endian::big));
   if (headerSize == 0)
     throw Error(ErrorCode::kerNoImageInInputData);
 
@@ -264,8 +265,8 @@ DataBuf PgfImage::readPgfHeaderStructure(BasicIo& iIo, uint32_t& width, uint32_t
 
   DataBuf work(8);  // don't disturb the binary data - doWriteMetadata reuses it
   std::copy_n(header.c_data(), 8, work.begin());
-  width = byteSwap_(work, 0, bSwap_);
-  height = byteSwap_(work, 4, bSwap_);
+  width = byteSwap_(work, 0, std::endian::native == std::endian::big);
+  height = byteSwap_(work, 4, std::endian::native == std::endian::big);
 
   /* NOTE: properties not yet used
   byte nLevels  = buffer.pData_[8];