4.58 beta

CPP/7zip/Archive/Lzma/LzmaIn.cpp

@@ -0,0 +1,56 @@
+// Archive/LzmaIn.cpp
+
+#include "StdAfx.h"
+
+#include "LzmaIn.h"
+
+#include "../../Common/StreamUtils.h"
+
+namespace NArchive {
+namespace NLzma {
+ 
+static bool CheckDictSize(const Byte *p)
+{
+  UInt32 dicSize = GetUi32(p);
+  int i;
+  for (i = 1; i <= 30; i++)
+    if (dicSize == ((UInt32)2 << i) || dicSize == ((UInt32)3 << i))
+      return true;
+  return false;
+}
+
+HRESULT ReadStreamHeader(ISequentialInStream *inStream, CHeader &block)
+{
+  Byte sig[5 + 9];
+  RINOK(ReadStream_FALSE(inStream, sig, 5 + 8));
+
+  const Byte kMaxProp0Val = 5 * 5 * 9 - 1;
+  if (sig[0] > kMaxProp0Val)
+    return S_FALSE;
+
+  for (int i = 0; i < 5; i++)
+    block.LzmaProps[i] = sig[i];
+  
+  block.IsThereFilter = false;
+  block.FilterMethod = 0;
+
+  if (!CheckDictSize(sig + 1))
+  {
+    if (sig[0] > 1 || sig[1] > kMaxProp0Val)
+      return S_FALSE;
+    block.IsThereFilter = true;
+    block.FilterMethod = sig[0];
+    for (int i = 0; i < 5; i++)
+      block.LzmaProps[i] = sig[i + 1];
+    if (!CheckDictSize(block.LzmaProps + 1))
+      return S_FALSE;
+    RINOK(ReadStream_FALSE(inStream, sig + 5 + 8, 1));
+  }
+  UInt32 unpOffset = 5 + (block.IsThereFilter ? 1 : 0);
+  block.UnpackSize = GetUi64(sig + unpOffset);
+  if (block.HasUnpackSize() && block.UnpackSize >= ((UInt64)1 << 56))
+    return S_FALSE;
+  return S_OK;
+}
+
+}}