From c7816c42f0d863ac57c3c29c1d8d8108369bea21 Mon Sep 17 00:00:00 2001
From: Ramkoemar <rbhoera@gmail.com>
Date: Mon, 26 Jun 2017 14:44:09 +0200
Subject: [PATCH] updated appendNal and added upgradeNal in DTSC lib, nal lib
 speedup

---
 lib/dtsc.h       |  6 ++++--
 lib/dtscmeta.cpp | 38 +++++++++++++++++++++++++-------------
 lib/nal.cpp      |  4 ++--
 3 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/lib/dtsc.h b/lib/dtsc.h
index 534a3876..84517c28 100644
--- a/lib/dtsc.h
+++ b/lib/dtsc.h
@@ -118,7 +118,6 @@ namespace DTSC {
       void reInit(Socket::Connection & src);
       void reInit(const char * data_, unsigned int len, bool noCopy = false);
       void genericFill(long long packTime, long long packOffset, long long packTrack, const char * packData, long long packDataSize, uint64_t packBytePos, bool isKeyframe);
-      void appendData(const char * appendData, uint32_t appendLen);
       void getString(const char * identifier, char *& result, unsigned int & len) const;
       void getString(const char * identifier, std::string & result) const;
       void getInt(const char * identifier, int & result) const;
@@ -126,7 +125,8 @@ namespace DTSC {
       void getFlag(const char * identifier, bool & result) const;
       bool getFlag(const char * identifier) const;
       bool hasMember(const char * identifier) const;
-      void appendNal(const char * appendData, uint32_t appendLen, uint32_t totalLen);
+      void appendNal(const char * appendData, uint32_t appendLen);
+      void upgradeNal(const char * appendData, uint32_t appendLen);
       void setKeyFrame(bool kf);
       long long unsigned int getTime() const;
       long int getTrackId() const;
@@ -145,6 +145,8 @@ namespace DTSC {
       char * data;
       unsigned int bufferLen;
       unsigned int dataLen;
+
+      uint64_t prevNalSize;
   };
 
   /// A simple structure used for ordering byte seek positions.
diff --git a/lib/dtscmeta.cpp b/lib/dtscmeta.cpp
index c8ac3ef6..985fc732 100644
--- a/lib/dtscmeta.cpp
+++ b/lib/dtscmeta.cpp
@@ -291,30 +291,42 @@ namespace DTSC {
     }
   }
 
-  void Packet::appendData(const char * appendData, uint32_t appendLen){
-    resize(dataLen + appendLen);
-    memcpy(data + dataLen-3, appendData, appendLen);
-    memcpy(data + dataLen-3 + appendLen, "\000\000\356", 3);  //end container
-    dataLen += appendLen;
-    Bit::htobl(data+4, Bit::btohl(data +4)+appendLen);
-    uint32_t offset = getDataStringLenOffset();
-    Bit::htobl(data+offset, Bit::btohl(data+offset)+appendLen);
-  }
-
-  void Packet::appendNal(const char * appendData, uint32_t appendLen, uint32_t totalLen){
-    if(totalLen ==0){
+  void Packet::appendNal(const char * appendData, uint32_t appendLen){
+    if(appendLen ==0){
       return;
     }
 
 //    INFO_MSG("totallen: %d, appendLen: %d",totalLen,appendLen);
     resize(dataLen + appendLen +4);
-    Bit::htobl(data+dataLen -3, totalLen);
+    Bit::htobl(data+dataLen -3, appendLen);
     memcpy(data + dataLen-3+4, appendData, appendLen);
     memcpy(data + dataLen-3+4 + appendLen, "\000\000\356", 3);  //end container
     dataLen += appendLen +4;
     Bit::htobl(data+4, Bit::btohl(data +4)+appendLen+4);
     uint32_t offset = getDataStringLenOffset();
     Bit::htobl(data+offset, Bit::btohl(data+offset)+appendLen+4);
+
+    prevNalSize = appendLen;
+  }
+
+  void Packet::upgradeNal(const char * appendData, uint32_t appendLen){
+    if(appendLen ==0){
+      return;
+    }
+    uint64_t sizeOffset = dataLen - 3 - 4 - prevNalSize;
+    if (Bit::btohl(data + sizeOffset) != prevNalSize){
+      FAIL_MSG("PrevNalSize state not correct");
+      return;
+    }
+    resize(dataLen + appendLen);//Not + 4 as size bytes have already been written here.
+    Bit::htobl(data+sizeOffset, prevNalSize + appendLen);
+    prevNalSize += appendLen;
+    memcpy(data + dataLen - 3, appendData, appendLen);
+    memcpy(data + dataLen - 3 + appendLen, "\000\000\356", 3);  //end container
+    dataLen += appendLen;
+    Bit::htobl(data+4, Bit::btohl(data +4)+appendLen);
+    uint32_t offset = getDataStringLenOffset();
+    Bit::htobl(data+offset, Bit::btohl(data+offset)+appendLen);
   }
 
   uint32_t Packet::getDataStringLen(){
diff --git a/lib/nal.cpp b/lib/nal.cpp
index 4a502005..379a03f5 100644
--- a/lib/nal.cpp
+++ b/lib/nal.cpp
@@ -82,8 +82,8 @@ namespace nalu {
     int offset = 0;
     while(offset+2 < dataSize){
       const char * begin = data + offset;
-      int t = (int)((begin[0] << 8)|((begin[1]) << 8)|(begin[2])); 
-      if(t != 1){
+      bool t = (begin[2] == 1 && !begin[0] && !begin[1]);
+      if(!t){
         if (begin[2]){//skip three bytes if the last one isn't zero
           offset +=3;
         }else if (begin[1]){//skip two bytes if the second one isn't zero