From cbb54d5aebe6fa7b7077ba29e729149d40d5fb72 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Tue, 20 Mar 2018 21:41:05 +0100
Subject: [PATCH] Allow custom writing application

---
 matroska/matroskacontainer.cpp | 21 ++++++++++++++-------
 mediafileinfo.h                | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/matroska/matroskacontainer.cpp b/matroska/matroskacontainer.cpp
index 8a90f98..5f0f679 100644
--- a/matroska/matroskacontainer.cpp
+++ b/matroska/matroskacontainer.cpp
@@ -33,10 +33,6 @@ using namespace ChronoUtilities;
 
 namespace TagParser {
 
-constexpr const char appInfo[] = APP_NAME " v" APP_VERSION;
-constexpr uint64 appInfoElementDataSize = sizeof(appInfo) - 1;
-constexpr uint64 appInfoElementTotalSize = 2 + 1 + appInfoElementDataSize;
-
 /*!
  * \class Media::MatroskaContainer
  * \brief Implementation of GenericContainer<MediaFileInfo, MatroskaTag, MatroskaTrack, EbmlElement>.
@@ -931,6 +927,16 @@ void MatroskaContainer::internalMakeFile(Diagnostics &diag, AbortableProgressFee
     ebmlHeaderDataSize += EbmlElement::calculateSizeDenotationLength(m_doctype.size());
     const uint64 ebmlHeaderSize = 4 + EbmlElement::calculateSizeDenotationLength(ebmlHeaderDataSize) + ebmlHeaderDataSize;
 
+    // calculate size of "WritingLib"-element
+    constexpr const char muxingAppName[] = APP_NAME " v" APP_VERSION;
+    constexpr uint64 muxingAppElementDataSize = sizeof(muxingAppName) - 1;
+    constexpr uint64 muxingAppElementTotalSize = 2 + 1 + muxingAppElementDataSize;
+
+    // calculate size of "WritingApp"-element
+    const uint64 writingAppElementDataSize
+        = fileInfo().writingApplication().empty() ? muxingAppElementDataSize : fileInfo().writingApplication().size() - 1;
+    const uint64 writingAppElementTotalSize = 2 + 1 + writingAppElementDataSize;
+
     try {
         // calculate size of "Tags"-element
         for (auto &tag : tags()) {
@@ -1103,7 +1109,7 @@ void MatroskaContainer::internalMakeFile(Diagnostics &diag, AbortableProgressFee
                     } else {
                         // add size of "SegmentInfo"-element
                         // -> size of "MuxingApp"- and "WritingApp"-element
-                        segment.infoDataSize = 2 * appInfoElementTotalSize;
+                        segment.infoDataSize = muxingAppElementTotalSize + writingAppElementTotalSize;
                         // -> add size of "Title"-element
                         if (segmentIndex < m_titles.size()) {
                             const auto &title = m_titles[segmentIndex];
@@ -1617,8 +1623,9 @@ void MatroskaContainer::internalMakeFile(Diagnostics &diag, AbortableProgressFee
                         }
                     }
                     // -> write "MuxingApp"- and "WritingApp"-element
-                    EbmlElement::makeSimpleElement(outputStream, MatroskaIds::MuxingApp, appInfo, appInfoElementDataSize);
-                    EbmlElement::makeSimpleElement(outputStream, MatroskaIds::WrittingApp, appInfo, appInfoElementDataSize);
+                    EbmlElement::makeSimpleElement(outputStream, MatroskaIds::MuxingApp, muxingAppName, muxingAppElementDataSize);
+                    EbmlElement::makeSimpleElement(outputStream, MatroskaIds::WrittingApp,
+                        fileInfo().writingApplication().empty() ? muxingAppName : fileInfo().writingApplication().data(), writingAppElementDataSize);
                 }
 
                 // write "Tracks"-element
diff --git a/mediafileinfo.h b/mediafileinfo.h
index 37f2bfc..58d2715 100644
--- a/mediafileinfo.h
+++ b/mediafileinfo.h
@@ -122,6 +122,9 @@ public:
     // methods to get, set object behaviour
     const std::string &saveFilePath() const;
     void setSaveFilePath(const std::string &saveFilePath);
+    const std::string writingApplication() const;
+    void setWritingApplication(const std::string &writingApplication);
+    void setWritingApplication(const char *writingApplication);
     bool isForcingFullParse() const;
     void setForceFullParse(bool forceFullParse);
     bool isForcingRewrite() const;
@@ -174,6 +177,7 @@ private:
 
     // fields specifying object behaviour
     std::string m_saveFilePath;
+    std::string m_writingApplication;
     size_t m_minPadding;
     size_t m_maxPadding;
     size_t m_preferredPadding;
@@ -363,6 +367,34 @@ inline void MediaFileInfo::setSaveFilePath(const std::string &saveFilePath)
     m_saveFilePath = saveFilePath;
 }
 
+/*!
+ * \brief Sets the writing application as container-level meta-data.
+ * \remarks This is not read from the file when parsing and only used when saving changes.
+ * \sa setWritingApplication() for more details
+ */
+inline const std::string MediaFileInfo::writingApplication() const
+{
+    return m_writingApplication;
+}
+
+/*!
+ * \brief Sets the writing application as container-level meta-data. Put the name of your application here.
+ * \remarks Might not be used (depends on the format).
+ */
+inline void MediaFileInfo::setWritingApplication(const std::string &writingApplication)
+{
+    m_writingApplication = writingApplication;
+}
+
+/*!
+ * \brief Sets the writing application as container-level meta-data. Put the name of your application here.
+ * \remarks Might not be used (depends on the format).
+ */
+inline void MediaFileInfo::setWritingApplication(const char *writingApplication)
+{
+    m_writingApplication = writingApplication;
+}
+
 /*!
  * \brief Returns the container for the current file.
  *