exifprint.cpp

Sample program to print Exif data from an image.

// SPDX-License-Identifier: GPL-2.0-or-later
 
#include <exiv2/exiv2.hpp>
#include <iostream>
#include <regex>
 
// copied from src/tiffvisitor_int.cpp
static const Exiv2::TagInfo* findTag(const Exiv2::TagInfo* pList, uint16_t tag) {
  while (pList->tag_ != 0xffff && pList->tag_ != tag)
    pList++;
  return pList->tag_ != 0xffff ? pList : nullptr;
}
 
int main(int argc, char* const argv[]) {
  try {
    setlocale(LC_CTYPE, ".utf8");
    Exiv2::XmpParser::initialize();
    ::atexit(Exiv2::XmpParser::terminate);
 
    const char* prog = argv[0];
    if (argc == 1) {
      std::cout << "Usage: " << prog << " [ [--lint] path | --version | --version-test ]" << std::endl;
      return EXIT_FAILURE;
    }
 
    int rc = EXIT_SUCCESS;
    const char* file = argv[1];
    bool bLint = strcmp(file, "--lint") == 0 && argc == 3;
    if (bLint)
      file = argv[2];
 
    if (strcmp(file, "--version") == 0) {
      std::vector<std::regex> keys;
      Exiv2::dumpLibraryInfo(std::cout, keys);
      return rc;
    }
    if (strcmp(file, "--version-test") == 0) {
      // verifies/test macro EXIV2_TEST_VERSION
      // described in include/exiv2/version.hpp
      std::cout << "EXV_PACKAGE_VERSION             " << EXV_PACKAGE_VERSION << std::endl
                << "Exiv2::version()                " << Exiv2::version() << std::endl
                << "strlen(Exiv2::version())        " << ::strlen(Exiv2::version()) << std::endl
                << "Exiv2::versionNumber()          " << Exiv2::versionNumber() << std::endl
                << "Exiv2::versionString()          " << Exiv2::versionString() << std::endl
                << "Exiv2::versionNumberHexString() " << Exiv2::versionNumberHexString() << std::endl;
 
// Test the Exiv2 version available at runtime but compile the if-clause only if
// the compile-time version is at least 0.15. Earlier versions didn't have a
// testVersion() function:
#if EXIV2_TEST_VERSION(0, 15, 0)
      if (Exiv2::testVersion(0, 13, 0)) {
        std::cout << "Available Exiv2 version is equal to or greater than 0.13\n";
      } else {
        std::cout << "Installed Exiv2 version is less than 0.13\n";
      }
#else
      std::cout << "Compile-time Exiv2 version doesn't have Exiv2::testVersion()\n";
#endif
      return rc;
    }
 
    auto image = Exiv2::ImageFactory::open(file);
    image->readMetadata();
 
    Exiv2::ExifData& exifData = image->exifData();
    if (exifData.empty()) {
      std::string error("No Exif data found in file");
      throw Exiv2::Error(Exiv2::ErrorCode::kerErrorMessage, error);
    }
 
    std::set<std::string> shortLong;
    shortLong.insert("Exif.Photo.PixelXDimension");
    shortLong.insert("Exif.Photo.PixelYDimension");
    shortLong.insert("Exif.Photo.ImageLength");
    shortLong.insert("Exif.Photo.ImageWidth");
    shortLong.insert("Exif.Photo.RowsPerStrip");
    shortLong.insert("Exif.Photo.StripOffsets");
    shortLong.insert("Exif.Photo.StripByteCounts");
 
    auto end = exifData.end();
    for (auto i = exifData.begin(); i != end; ++i) {
      if (!bLint) {
        const char* tn = i->typeName();
        std::cout << std::setw(44) << std::setfill(' ') << std::left << i->key() << " "
                  << "0x" << std::setw(4) << std::setfill('0') << std::right << std::hex << i->tag() << " "
                  << std::setw(9) << std::setfill(' ') << std::left << (tn ? tn : "Unknown") << " " << std::dec
                  << std::setw(3) << std::setfill(' ') << std::right << i->count() << "  " << std::dec << i->toString()
                  << "\n";
      } else {
        const Exiv2::TagInfo* tagInfo = findTag(Exiv2::ExifTags::tagList(i->groupName()), i->tag());
        if (tagInfo) {
          Exiv2::TypeId type = i->typeId();
          if (type != tagInfo->typeId_ &&
              (tagInfo->typeId_ != Exiv2::comment || type != Exiv2::undefined)  // comment is stored as undefined
              && (shortLong.find(i->key()) == shortLong.end() ||
                  (type != Exiv2::unsignedShort && type != Exiv2::unsignedLong))  // can be short or long!
          ) {
            std::cerr << i->key() << " type " << i->typeName() << " (" << type << ")"
                      << " expected " << Exiv2::TypeInfo::typeName(tagInfo->typeId_) << " (" << tagInfo->typeId_ << ")"
                      << std::endl;
            rc = 2;
          }
        }
      }
    }
 
    return rc;
  } catch (Exiv2::Error& e) {
    std::cout << "Caught Exiv2 exception '" << e.what() << "'\n";
    return EXIT_FAILURE;
  }
}