1 files changed, 160 insertions, 0 deletions
diff --git a/src/jpeg/jpeg_segment_builder.cc b/src/jpeg/jpeg_segment_builder.cc
new file mode 100644
index 0000000..aafb525
--- /dev/null
+++ b/src/jpeg/jpeg_segment_builder.cc
@@ -0,0 +1,160 @@
+#include "image_io/jpeg/jpeg_segment_builder.h"
+
+#include "image_io/jpeg/jpeg_marker.h"
+
+namespace photos_editing_formats {
+namespace image_io {
+
+using std::string;
+
+// The strings needed to build the xml data associated with XMP data. See
+// https://wwwimages2.adobe.com/content/dam/acom/en/devnet/xmp/pdfs/
+//   XMP%20SDK%20Release%20cc-2016-08/XMPSpecificationPart1.pdf
+const char kXmpMetaPrefix[] = "<x:xmpmeta xmlns:x=\"adobe:ns:meta/\">";
+const char kXmpMetaSuffix[] = "</x:xmpmeta>";
+const char kRdfPrefix[] =
+    "<rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\""
+    "xmlns:xmp=\"http://ns.adobe.com/xap/1.0/\">";
+const char kRdfSuffix[] = "</rdf:RDF>";
+const char kRdfDescriptionPrefix[] = "<rdf:Description rdf:about=\"\"";
+const char kRdfDescriptionSuffix[] = "/>";
+
+bool JpegSegmentBuilder::SetPayloadSize(ByteBuffer* byte_buffer) {
+  std::uint16_t size = byte_buffer->GetSize();
+  if (size == byte_buffer->GetSize() && size >= 4) {
+    return byte_buffer->SetBigEndianValue(2, size - 2);
+  }
+  return false;
+}
+
+string JpegSegmentBuilder::GetByteDataValues() const {
+  string values;
+  for (const auto& byte_datum : byte_data_) {
+    if (!byte_datum.IsValid()) {
+      return "";
+    }
+    values += byte_datum.GetValue();
+    if (byte_datum.GetType() == ByteData::kAscii0) {
+      values.append(1, 0);
+    }
+  }
+  return values;
+}
+
+void JpegSegmentBuilder::AddMarkerAndSize(Byte marker_type, size_t size) {
+  JpegMarker marker(marker_type);
+  string hex_string = marker.GetHexString("FF");
+  if (marker.HasVariablePayloadSize()) {
+    hex_string += ByteData::Byte2Hex((size >> 8) & 0xFF);
+    hex_string += ByteData::Byte2Hex(size & 0xFF);
+  }
+  byte_data_.emplace_back(ByteData::kHex, hex_string);
+}
+
+size_t JpegSegmentBuilder::AddMarkerAndSizePlaceholder(Byte marker_type) {
+  JpegMarker marker(marker_type);
+  string hex_string = marker.GetHexString("FF");
+  if (marker.HasVariablePayloadSize()) {
+    hex_string += "0000";
+  }
+  byte_data_.emplace_back(ByteData::kHex, hex_string);
+  return byte_data_.size() - 1;
+}
+
+bool JpegSegmentBuilder::ReplaceSizePlaceholder(size_t index, size_t size) {
+  if (index >= byte_data_.size() || size < 2 || size > 0xFFFF) {
+    return false;
+  }
+  const ByteData& byte_datum = byte_data_[index];
+  if (byte_datum.GetType() != ByteData::kHex) {
+    return false;
+  }
+  string value = byte_datum.GetValue();
+  if (value.length() < 4) {
+    return false;
+  }
+  Byte flag, type;
+  if (!ByteData::Hex2Byte(value[0], value[1], &flag) ||
+      !ByteData::Hex2Byte(value[2], value[3], &type)) {
+    return false;
+  }
+  JpegMarker marker(type);
+  if (flag != JpegMarker::kStart || !marker.IsValid() ||
+      !marker.HasVariablePayloadSize()) {
+    return false;
+  }
+  value.replace(2, 2, ByteData::Byte2Hex((size >> 8) & 0xFF));
+  value.replace(4, 2, ByteData::Byte2Hex(size & 0xFF));
+  byte_data_[index] = ByteData(ByteData::kHex, value);
+  return true;
+}
+
+void JpegSegmentBuilder::AddExtendedXmpHeader(const std::string& xmp_guid) {
+  string guid_value(xmp_guid);
+  guid_value.resize(kXmpGuidSize, '0');
+  byte_data_.emplace_back(ByteData::kAscii0, kXmpExtendedId);
+  byte_data_.emplace_back(ByteData::kAscii, guid_value);
+  byte_data_.emplace_back(ByteData::kAscii, string(8, '0'));
+}
+
+void JpegSegmentBuilder::AddXmpMetaPrefix() {
+  byte_data_.emplace_back(ByteData::kAscii, kXmpMetaPrefix);
+}
+
+void JpegSegmentBuilder::AddXmpMetaSuffix() {
+  byte_data_.emplace_back(ByteData::kAscii, kXmpMetaSuffix);
+}
+
+void JpegSegmentBuilder::AddRdfPrefix() {
+  byte_data_.emplace_back(ByteData::kAscii, kRdfPrefix);
+}
+
+void JpegSegmentBuilder::AddRdfSuffix() {
+  byte_data_.emplace_back(ByteData::kAscii, kRdfSuffix);
+}
+
+void JpegSegmentBuilder::AddRdfDescriptionPrefix() {
+  byte_data_.emplace_back(ByteData::kAscii, kRdfDescriptionPrefix);
+}
+
+void JpegSegmentBuilder::AddRdfDescriptionSuffix() {
+  byte_data_.emplace_back(ByteData::kAscii, kRdfDescriptionSuffix);
+}
+
+void JpegSegmentBuilder::AddXmpPropertyPrefix(
+    const std::string& property_name) {
+  string property_name_equals_quote = property_name + "=\"";
+  byte_data_.emplace_back(ByteData::kAscii, property_name_equals_quote);
+}
+
+void JpegSegmentBuilder::AddXmpPropertySuffix() {
+  byte_data_.emplace_back(ByteData::kAscii, "\"");
+}
+
+void JpegSegmentBuilder::AddXmpPropertyNameAndValue(
+    const std::string& property_name, const std::string& property_value) {
+  AddXmpPropertyPrefix(property_name);
+  byte_data_.emplace_back(ByteData::kAscii, property_value);
+  AddXmpPropertySuffix();
+}
+
+void JpegSegmentBuilder::AddApp1XmpMarkerAndXmpExtendedHeader(
+    const std::string& xmp_guid) {
+  AddMarkerAndSizePlaceholder(JpegMarker::kAPP1);
+  AddExtendedXmpHeader(xmp_guid);
+}
+
+void JpegSegmentBuilder::AddXmpAndRdfPrefixes() {
+  AddXmpMetaPrefix();
+  AddRdfPrefix();
+  AddRdfDescriptionPrefix();
+}
+
+void JpegSegmentBuilder::AddXmpAndRdfSuffixes() {
+  AddRdfDescriptionSuffix();
+  AddRdfSuffix();
+  AddXmpMetaSuffix();
+}
+
+}  // namespace image_io
+}  // namespace photos_editing_formats