Initial commit

lib/nal.cpp

@@ -0,0 +1,71 @@
+#include "nal.h"
+
+NAL_Unit::NAL_Unit( ) {
+  
+}
+
+NAL_Unit::NAL_Unit( std::string & InputData ) {
+  ReadData( InputData );
+}
+
+bool NAL_Unit::ReadData( std::string & InputData ) {
+  std::string FullAnnexB;
+  FullAnnexB += (char)0x00;
+  FullAnnexB += (char)0x00;
+  FullAnnexB += (char)0x00;
+  FullAnnexB += (char)0x01;
+  std::string ShortAnnexB;
+  ShortAnnexB += (char)0x00;
+  ShortAnnexB += (char)0x00;
+  ShortAnnexB += (char)0x01;
+//  fprintf( stderr, "NAL_Unit::ReadData --- DataSize: %d\n", InputData.size() );
+  if( InputData.size() < 3 ) { return false; }
+  bool AnnexB = false;
+  if( InputData.substr(0,3) == ShortAnnexB ) { AnnexB = true; }
+  if( InputData.substr(0,4) == FullAnnexB ) { InputData.erase(0,1); AnnexB = true; }
+  if( AnnexB ) {
+    MyData = "";
+    InputData.erase(0,3);//Intro Bytes
+    bool FinalByteRead = false;
+    int Location = std::min( InputData.find( ShortAnnexB ), InputData.find( FullAnnexB ) );
+    MyData = InputData.substr(0,Location);
+    InputData.erase(0,Location);
+  } else {
+    if( InputData.size() < 4 ) { return false; }
+    int UnitLen = (InputData[0] << 24) + (InputData[1] << 16) + (InputData[2] << 8) + InputData[3];
+    if( InputData.size() < 4+UnitLen ) { return false; }
+    InputData.erase(0,4);//Remove Length
+    MyData = InputData.substr(0,UnitLen);
+    InputData.erase(0,UnitLen);//Remove this unit from the string
+  }
+  return true;
+}
+
+std::string NAL_Unit::AnnexB( bool LongIntro ) {
+  std::string Result;
+  if( MyData.size() ) {
+    if( LongIntro ) { Result += (char)0x00; }
+    Result += (char)0x00;
+    Result += (char)0x00;
+    Result += (char)0x01;//Annex B Lead-In
+    Result += MyData;
+  }
+  return Result;
+}
+
+std::string NAL_Unit::SizePrepended( ) {
+  std::string Result;
+  if( MyData.size() ) {
+    int DataSize = MyData.size();
+    Result += (char)( ( DataSize & 0xFF000000 ) >> 24 );
+    Result += (char)( ( DataSize & 0x00FF0000 ) >> 16 );
+    Result += (char)( ( DataSize & 0x0000FF00 ) >> 8 );
+    Result += (char)(   DataSize & 0x000000FF );//Size Lead-In
+    Result += MyData;
+  }
+  return Result;
+}
+
+int NAL_Unit::Type( ) {
+  return ( MyData[0] & 0x1F );
+}