4.44 beta

CPP/7zip/Archive/Cab/CabBlockInStream.cpp

@@ -0,0 +1,194 @@
+// CabBlockInStream.cpp
+
+#include "StdAfx.h"
+
+#include "Common/Alloc.h"
+#include "Common/Defs.h"
+
+#include "../../Common/StreamUtils.h"
+
+#include "CabBlockInStream.h"
+
+namespace NArchive {
+namespace NCab {
+
+static const UInt32 kBlockSize = (1 << 16);
+
+bool CCabBlockInStream::Create()
+{
+  if (!_buffer)
+    _buffer = (Byte *)::MyAlloc(kBlockSize);
+  return (_buffer != 0);
+}
+
+CCabBlockInStream::~CCabBlockInStream()
+{
+  MyFree(_buffer);
+}
+
+class CCheckSum2
+{
+  UInt32 m_Value;
+  int m_Pos;
+  Byte m_Hist[4];
+public:
+  CCheckSum2(): m_Value(0){};
+  void Init() { m_Value = 0;  m_Pos = 0; }
+  void Update(const void *data, UInt32 size);
+  void FinishDataUpdate()
+  {
+    for (int i = 0; i < m_Pos; i++)
+      m_Value ^= ((UInt32)(m_Hist[i])) << (8 * (m_Pos - i - 1));
+  }
+  void UpdateUInt32(UInt32 v) { m_Value ^= v; }
+  UInt32 GetResult() const {  return m_Value; } 
+};
+
+void CCheckSum2::Update(const void *data, UInt32 size)
+{
+  UInt32 checkSum = m_Value;
+  const Byte *dataPointer = (const Byte *)data;
+
+  while (size != 0 && m_Pos != 0)
+  {
+    m_Hist[m_Pos] = *dataPointer++;
+    m_Pos = (m_Pos + 1) & 3;
+    size--;
+    if (m_Pos == 0)
+      for (int i = 0; i < 4; i++)
+        checkSum ^= ((UInt32)m_Hist[i]) << (8 * i);
+  }
+
+  int numWords = size / 4;
+  
+  while (numWords-- != 0) 
+  {
+    UInt32 temp = *dataPointer++;
+    temp |= ((UInt32)(*dataPointer++)) <<  8;
+    temp |= ((UInt32)(*dataPointer++)) << 16;
+    temp |= ((UInt32)(*dataPointer++)) << 24;
+    checkSum ^= temp;
+  }
+  m_Value = checkSum;
+
+  size &= 3;
+  
+  while (size != 0)
+  {
+    m_Hist[m_Pos] = *dataPointer++;
+    m_Pos = (m_Pos + 1) & 3;
+    size--;
+  }
+}
+
+static const UInt32 kDataBlockHeaderSize = 8;
+
+class CTempCabInBuffer2
+{
+public:
+  Byte Buffer[kDataBlockHeaderSize];
+  UInt32 Pos;
+  Byte ReadByte()
+  {
+    return Buffer[Pos++];
+  }
+  UInt32 ReadUInt32()
+  {
+    UInt32 value = 0;
+    for (int i = 0; i < 4; i++)
+      value |= (((UInt32)ReadByte()) << (8 * i));
+    return value;
+  }
+  UInt16 ReadUInt16()
+  {
+    UInt16 value = 0;
+    for (int i = 0; i < 2; i++)
+      value |= (((UInt16)ReadByte()) << (8 * i));
+    return value;
+  }
+};
+
+HRESULT CCabBlockInStream::PreRead(UInt32 &packSize, UInt32 &unpackSize)
+{
+  CTempCabInBuffer2 inBuffer;
+  inBuffer.Pos = 0;
+  UInt32 processedSizeLoc; 
+  RINOK(ReadStream(_stream, inBuffer.Buffer, kDataBlockHeaderSize, &processedSizeLoc))
+  if (processedSizeLoc != kDataBlockHeaderSize)
+    return S_FALSE;  // bad block
+
+  UInt32 checkSum = inBuffer.ReadUInt32();
+  packSize = inBuffer.ReadUInt16();
+  unpackSize = inBuffer.ReadUInt16();
+  if (ReservedSize != 0)
+  {
+    RINOK(ReadStream(_stream, _buffer, ReservedSize, &processedSizeLoc));
+    if(ReservedSize != processedSizeLoc)
+      return S_FALSE; // bad block;
+  }
+  _pos = 0;
+  CCheckSum2 checkSumCalc;
+  checkSumCalc.Init();
+  UInt32 packSize2 = packSize;
+  if (MsZip && _size == 0)
+  {
+    if (packSize < 2)
+      return S_FALSE; // bad block;
+    Byte sig[2];
+    RINOK(ReadStream(_stream, sig, 2, &processedSizeLoc));
+    if(processedSizeLoc != 2)
+      return S_FALSE;
+    if (sig[0] != 0x43 || sig[1] != 0x4B)
+      return S_FALSE;
+    packSize2 -= 2;
+    checkSumCalc.Update(sig, 2);
+  }
+
+  if (kBlockSize - _size < packSize2)
+    return S_FALSE;
+
+  UInt32 curSize = packSize2;
+  if (curSize != 0)
+  {
+    RINOK(ReadStream(_stream, _buffer + _size, curSize, &processedSizeLoc));
+    checkSumCalc.Update(_buffer + _size, processedSizeLoc);
+    _size += processedSizeLoc;
+    if (processedSizeLoc != curSize)
+      return S_FALSE;
+  }
+  TotalPackSize = _size;
+
+  checkSumCalc.FinishDataUpdate();
+  
+  bool dataError;
+  if (checkSum == 0)
+    dataError = false;
+  else
+  {
+    checkSumCalc.UpdateUInt32(packSize | (((UInt32)unpackSize) << 16));
+    dataError = (checkSumCalc.GetResult() != checkSum);
+  }
+  DataError |= dataError;
+  return dataError ? S_FALSE : S_OK;
+}
+
+STDMETHODIMP CCabBlockInStream::Read(void *data, UInt32 size, UInt32 *processedSize)
+{
+  if (processedSize != 0)
+    *processedSize = 0;
+  if (size == 0)
+    return S_OK;
+  if (_size != 0)
+  {
+    size = MyMin(_size, size);
+    memmove(data, _buffer + _pos, size);
+    _pos += size;
+    _size -= size;
+    if (processedSize != 0)
+      *processedSize = size;
+    return S_OK;
+  }
+  return S_OK; // no blocks data
+}
+
+}}