1 files changed, 64 insertions, 0 deletions
diff --git a/other-licenses/7zstub/src/C/Delta.c b/other-licenses/7zstub/src/C/Delta.c
new file mode 100644
index 000000000..6cbbe4601
--- /dev/null
+++ b/other-licenses/7zstub/src/C/Delta.c
@@ -0,0 +1,64 @@
+/* Delta.c -- Delta converter
+2009-05-26 : Igor Pavlov : Public domain */
+
+#include "Precomp.h"
+
+#include "Delta.h"
+
+void Delta_Init(Byte *state)
+{
+  unsigned i;
+  for (i = 0; i < DELTA_STATE_SIZE; i++)
+    state[i] = 0;
+}
+
+static void MyMemCpy(Byte *dest, const Byte *src, unsigned size)
+{
+  unsigned i;
+  for (i = 0; i < size; i++)
+    dest[i] = src[i];
+}
+
+void Delta_Encode(Byte *state, unsigned delta, Byte *data, SizeT size)
+{
+  Byte buf[DELTA_STATE_SIZE];
+  unsigned j = 0;
+  MyMemCpy(buf, state, delta);
+  {
+    SizeT i;
+    for (i = 0; i < size;)
+    {
+      for (j = 0; j < delta && i < size; i++, j++)
+      {
+        Byte b = data[i];
+        data[i] = (Byte)(b - buf[j]);
+        buf[j] = b;
+      }
+    }
+  }
+  if (j == delta)
+    j = 0;
+  MyMemCpy(state, buf + j, delta - j);
+  MyMemCpy(state + delta - j, buf, j);
+}
+
+void Delta_Decode(Byte *state, unsigned delta, Byte *data, SizeT size)
+{
+  Byte buf[DELTA_STATE_SIZE];
+  unsigned j = 0;
+  MyMemCpy(buf, state, delta);
+  {
+    SizeT i;
+    for (i = 0; i < size;)
+    {
+      for (j = 0; j < delta && i < size; i++, j++)
+      {
+        buf[j] = data[i] = (Byte)(buf[j] + data[i]);
+      }
+    }
+  }
+  if (j == delta)
+    j = 0;
+  MyMemCpy(state, buf + j, delta - j);
+  MyMemCpy(state + delta - j, buf, j);
+}