* extended_sections) { string guid = GetGUID(buffer); // Increment by 1 for the null byte in the middle. const int header_length = static_cast(strlen(XmpConst::ExtensionHeader()) + 1 + guid.length()); const int buffer_length = static_cast(buffer.length()); const int overhead = header_length + XmpConst::ExtensionHeaderOffset(); const int num_sections = buffer_length / (XmpConst::ExtendedMaxBufferSize() - overhead) + 1; for (int i = 0, position = 0; i < num_sections; ++i) { const int section_size = std::min(static_cast(buffer_length - position + overhead), XmpConst::ExtendedMaxBufferSize()); const int bytes_from_buffer = section_size - overhead; // Header and GUID. std::ostringstream data_stream; data_stream.write(XmpConst::ExtensionHeader(), strlen(XmpConst::ExtensionHeader())); data_stream.write(kCEmptyString, 1); data_stream.write(guid.c_str(), guid.length()); // Total buffer length. WriteIntTo4Bytes(buffer_length, &data_stream); // Current position. WriteIntTo4Bytes(position, &data_stream); // Data data_stream.write(&buffer[position], bytes_from_buffer); position += bytes_from_buffer; extended_sections->push_back(Section(data_stream.str())); } } int InsertStandardXMPSection(const string& buffer, std::vector

* sections) { if (buffer.length() > XmpConst::MaxBufferSize()) { LOG(WARNING) << "The standard XMP section (at size " << buffer.length() << ") cannot have a size larger than " << XmpConst::MaxBufferSize() << " bytes"; return kInvalidIndex; } string value; CreateStandardSectionXmpString(buffer, &value); Section xmp_section(value); // If we can find the old XMP section, replace it with the new one for (int index = 0; index < sections->size(); ++index) { if (sections->at(index).IsMarkerApp1() && StartsWith(sections->at(index).data, XmpConst::Header())) { // Replace with the new XMP data. sections->at(index) = xmp_section; return index; } } // If the first section is EXIF, insert XMP data after it. // Otherwise, make XMP data the first section. const int position = (!sections->empty() && sections->at(0).IsMarkerApp1()) ? 1 : 0; sections->emplace(sections->begin() + position, xmp_section); return position; } // Position is the index in the Section vector where the extended sections // will be inserted. void InsertExtendedXMPSections(const string& buffer, int position, std::vector

* sections) { std::vector

extended_sections; CreateExtendedSections(buffer, &extended_sections); sections->insert(sections->begin() + position, extended_sections.begin(), extended_sections.end()); } // Returns true if the respective sections in xmp_data and their serialized // counterparts are (correspondingly) not null and not empty. bool XmpSectionsAndSerializedDataValid(const XmpData& xmp_data, const string& main_buffer, const string& extended_buffer) { // Standard section and its serialized counterpart cannot be null/empty. // Extended section can be null XOR the extended buffer can be empty. const bool extended_is_consistent = ((xmp_data.ExtendedSection() == nullptr) == extended_buffer.empty()); const bool is_valid = (xmp_data.StandardSection() != nullptr) && !main_buffer.empty() && extended_is_consistent; if (!is_valid) { LOG(ERROR) << "XMP sections Xor their serialized counterparts are empty"; } return is_valid; } // Updates a list of JPEG sections with serialized XMP data. bool UpdateSections(const string& main_buffer, const string& extended_buffer, std::vector

* sections) { if (main_buffer.empty()) { LOG(WARNING) << "Main section was empty"; return false; } // Update the list of sections with the new standard XMP section. const int main_index = InsertStandardXMPSection(main_buffer, sections); if (main_index < 0) { LOG(WARNING) << "Could not find a valid index for inserting the " << "standard sections"; return false; } // Insert the extended section right after the main section. if (!extended_buffer.empty()) { InsertExtendedXMPSections(extended_buffer, main_index + 1, sections); } return true; } void LinkXmpStandardAndExtendedSections(const string& extended_buffer, xmlDocPtr standard_section) { xmlNodePtr description_node = GetFirstDescriptionElement(standard_section); xmlNsPtr xmp_note_ns_ptr = xmlNewNs(description_node, ToXmlChar(XmpConst::NoteNamespace()), ToXmlChar(XmpConst::HasExtensionPrefix())); const string extended_id = GetGUID(extended_buffer); xmlSetNsProp(description_node, xmp_note_ns_ptr, ToXmlChar(XmpConst::HasExtension()), ToXmlChar(extended_id.c_str())); xmlUnsetProp(description_node, ToXmlChar(XmpConst::HasExtension())); } } // namespace std::unique_ptr CreateXmpData(bool create_extended) { std::unique_ptr xmp_data(new XmpData()); *xmp_data->MutableStandardSection() = CreateXmpSection(); if (create_extended) { *xmp_data->MutableExtendedSection() = CreateXmpSection(); } return xmp_data; } bool WriteLeftEyeAndXmpMeta(const string& left_data, const string& filename, const XmpData& xmp_data) { std::istringstream input_jpeg_stream(left_data); std::ofstream output_jpeg_stream; output_jpeg_stream.open(filename, std::ostream::out); bool success = WriteLeftEyeAndXmpMeta(xmp_data, &input_jpeg_stream, &output_jpeg_stream); output_jpeg_stream.close(); return success; } bool WriteLeftEyeAndXmpMeta(const XmpData& xmp_data, std::istream* input_jpeg_stream, std::ostream* output_jpeg_stream) { if (input_jpeg_stream == nullptr || output_jpeg_stream == nullptr) { LOG(ERROR) << "Input and output streams must both be non-null"; return false; } // Get a list of sections from the input stream. ParseOptions parse_options; std::vector

sections = Parse(parse_options, input_jpeg_stream); string extended_buffer; if (xmp_data.ExtendedSection() != nullptr) { SerializeMeta(xmp_data.ExtendedSection(), &extended_buffer); LinkXmpStandardAndExtendedSections(extended_buffer, xmp_data.StandardSection()); } string main_buffer; SerializeMeta(xmp_data.StandardSection(), &main_buffer); // Update the input sections with the XMP data. if (!XmpSectionsAndSerializedDataValid(xmp_data, main_buffer, extended_buffer) || !UpdateSections(main_buffer, extended_buffer, §ions)) { return false; } WriteSections(sections, output_jpeg_stream); return true; } } // namespace xmpmeta } // namespace dynamic_depth