7zip tar pax header patch

TarUpdate.diff

*** old/TarUpdate.cpp
--- new/TarUpdate.cpp
***************
*** 13,25 ****
  namespace NArchive {
  namespace NTar {
  
  HRESULT UpdateArchive(IInStream *inStream, ISequentialOutStream *outStream,
      const CObjectVector<NArchive::NTar::CItemEx> &inputItems,
!     const CObjectVector<CUpdateItem> &updateItems,
      IArchiveUpdateCallback *updateCallback)
  {
    COutArchive outArchive;
    outArchive.Create(outStream);
  
    UInt64 complexity = 0;
  
--- 13,44 ----
  namespace NArchive {
  namespace NTar {
  
+ static int CompareTarUpdateItems(void *const *x, void *const *y, void *)
+ {
+     const CUpdateItem* p1 = *((const CUpdateItem**)x);
+     const CUpdateItem* p2 = *((const CUpdateItem**)y);
+     
+     if(!(p1->NewProps || p2->NewProps)) //Both are existing files
+         return MyCompare(p1->IndexInArchive, p2->IndexInArchive);
+     
+     if(p1->NewProps!=p2->NewProps)
+         return p1->NewProps?1:-1; //We want the existing file on the top
+     
+     return 0;
+ }
+ 
  HRESULT UpdateArchive(IInStream *inStream, ISequentialOutStream *outStream,
      const CObjectVector<NArchive::NTar::CItemEx> &inputItems,
!     const CObjectVector<CUpdateItem> &updateItemsUnsorted,
      IArchiveUpdateCallback *updateCallback)
  {
    COutArchive outArchive;
    outArchive.Create(outStream);
+   
+   //Sort the update items to make sure that the existing files
+   //are handled first. This preserves the ordering of pax headers.
+   CObjectVector<CUpdateItem> updateItems(updateItemsUnsorted);
+   updateItems.Sort(CompareTarUpdateItems, (void*)NULL);
  
    UInt64 complexity = 0;