1HEADmaster

1 files changed, 94 insertions, 0 deletions

diff --git a/tier1/undiff.cpp b/tier1/undiff.cpp
new file mode 100644
index 0000000..c39d8d4
--- /dev/null
+++ b/tier1/undiff.cpp
@@ -0,0 +1,94 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// UnDiff - Apply difference block
+//
+//=============================================================================//
+
+#include "tier0/platform.h"
+#include "tier0/dbg.h"
+#include "tier1/diff.h"
+#include "mathlib/mathlib.h"
+
+// memdbgon must be the last include file in a .cpp file!!!
+#include "tier0/memdbgon.h"
+
+void ApplyDiffs(uint8 const *OldBlock, uint8 const *DiffList,
+                int OldSize, int DiffListSize, int &ResultListSize,uint8 *Output,uint32 OutSize)
+{
+  uint8 const *copy_src=OldBlock;
+  uint8 const *end_of_diff_list=DiffList+DiffListSize;
+  uint8 const *obuf=Output;
+  while(DiffList<end_of_diff_list)
+  {
+    //  printf("dptr=%x ",DiffList-d);
+    uint8 op=*(DiffList++);
+    if (op==0)
+    {
+      uint16 copy_sz=DiffList[0]+256*DiffList[1];
+      int copy_ofs=DiffList[2]+DiffList[3]*256;
+      if (copy_ofs>32767)
+        copy_ofs|=0xffff0000;
+    //    printf("long cp from %x to %x len=%d\n", copy_src+copy_ofs-OldBlock,Output-obuf,copy_sz);
+      
+      memcpy(Output,copy_src+copy_ofs,copy_sz);
+      Output+=copy_sz;
+      copy_src=copy_src+copy_ofs+copy_sz;
+      DiffList+=4;
+    }
+    else
+    {
+      if (op & 0x80)
+      {
+        int copy_sz=op & 0x7f;
+        int copy_ofs;
+        if (copy_sz==0)
+        {
+          copy_sz=DiffList[0];
+          if (copy_sz==0)
+          {
+            // big raw copy
+            copy_sz=DiffList[1]+256*DiffList[2]+65536*DiffList[3];
+            memcpy(Output,DiffList+4,copy_sz);
+    //          printf("big rawcopy to %x len=%d\n", Output-obuf,copy_sz);
+            
+            DiffList+=copy_sz+4;
+            Output+=copy_sz;
+          }
+          else
+          {
+            copy_ofs=DiffList[1]+(DiffList[2]*256);
+            if (copy_ofs>32767)
+              copy_ofs|=0xffff0000;
+    //          printf("long ofs cp from %x to %x len=%d\n", copy_src+copy_ofs-OldBlock,Output-obuf,copy_sz);
+            
+            memcpy(Output,copy_src+copy_ofs,copy_sz);
+            Output+=copy_sz;
+            copy_src=copy_src+copy_ofs+copy_sz;
+            DiffList+=3;
+          }
+        }
+        else
+        {
+          copy_ofs=DiffList[0];
+          if (copy_ofs>127)
+            copy_ofs|=0xffffff80;
+    //        printf("cp from %x to %x len=%d\n", copy_src+copy_ofs-OldBlock,Output-obuf,copy_sz);
+          
+          memcpy(Output,copy_src+copy_ofs,copy_sz);
+          Output+=copy_sz;
+          copy_src=copy_src+copy_ofs+copy_sz;
+          DiffList++;
+        }
+      }
+      else
+      {
+    //      printf("raw copy %d to %x\n",op & 127,Output-obuf);
+        memcpy(Output,DiffList,op & 127);
+        Output+=op & 127;
+        DiffList+=(op & 127);
+      }
+    }
+  }
+  ResultListSize=Output-obuf;
+  
+}