rarin.cpp

著名的7zip的压缩算法,压缩比最高,但是压缩时间也比较长!

    item.Name = buffer;

    if(item.HasUnicodeName())
    {
      if(mainLen < nameSize)
      {
        int unicodeNameSizeMax = MyMin(nameSize, (0x400));
        _unicodeNameBuffer.EnsureCapacity(unicodeNameSizeMax + 1);
        DecodeUnicodeFileName(buffer, (const Byte *)buffer + mainLen + 1, 
            nameSize - (mainLen + 1), _unicodeNameBuffer, unicodeNameSizeMax);
        item.UnicodeName = _unicodeNameBuffer;
      }
      else if (!ConvertUTF8ToUnicode(item.Name, item.UnicodeName))
        item.UnicodeName.Empty();
    }
  }
  else
    item.Name.Empty();
}

Byte CInArchive::ReadByte()
{
  if (m_CurPos >= m_PosLimit)
    throw CInArchiveException(CInArchiveException::kIncorrectArchive);
  return m_CurData[m_CurPos++];
}

UInt16 CInArchive::ReadUInt16()
{
  UInt16 value = 0;
  for (int i = 0; i < 2; i++)
  {
    Byte b = ReadByte();
    value |= (UInt16(b) << (8 * i));
  }
  return value;
}

UInt32 CInArchive::ReadUInt32()
{
  UInt32 value = 0;
  for (int i = 0; i < 4; i++)
  {
    Byte b = ReadByte();
    value |= (UInt32(b) << (8 * i));
  }
  return value;
}

void CInArchive::ReadTime(Byte mask, CRarTime &rarTime)
{
  rarTime.LowSecond = ((mask & 4) != 0) ? 1 : 0;
  int numDigits = (mask & 3);
  rarTime.SubTime[0] = rarTime.SubTime[1] = rarTime.SubTime[2] = 0;
  for (int i = 0; i < numDigits; i++)
    rarTime.SubTime[3 - numDigits + i] = ReadByte();
}

void CInArchive::ReadHeaderReal(CItemEx &item)
{
  item.Flags = m_BlockHeader.Flags; 
  item.PackSize = ReadUInt32();
  item.UnPackSize = ReadUInt32();
  item.HostOS = ReadByte();
  item.FileCRC = ReadUInt32();
  item.LastWriteTime.DosTime = ReadUInt32();
  item.UnPackVersion = ReadByte();
  item.Method = ReadByte();
  int nameSize = ReadUInt16();
  item.Attributes = ReadUInt32();

  item.LastWriteTime.LowSecond = 0;
  item.LastWriteTime.SubTime[0] = 
      item.LastWriteTime.SubTime[1] = 
      item.LastWriteTime.SubTime[2] = 0;

  if((item.Flags & NHeader::NFile::kSize64Bits) != 0)
  {
    item.PackSize |= ((UInt64)ReadUInt32() << 32);
    item.UnPackSize |= ((UInt64)ReadUInt32() << 32);
  }

  ReadName(item, nameSize);

  if (item.HasSalt())
    for (int i = 0; i < sizeof(item.Salt); i++)
      item.Salt[i] = ReadByte();

  if (item.HasExtTime())
  {
    Byte accessMask = ReadByte() >> 4;
    Byte b = ReadByte();
    Byte modifMask = b >> 4;
    Byte createMask = b & 0xF;
    if ((modifMask & 8) != 0)
      ReadTime(modifMask, item.LastWriteTime);
    if (item.IsCreationTimeDefined = ((createMask & 8) != 0))
    {
      item.CreationTime.DosTime = ReadUInt32();
      ReadTime(createMask, item.CreationTime);
    }
    if (item.IsLastAccessTimeDefined = ((accessMask & 8) != 0))
    {
      item.LastAccessTime.DosTime = ReadUInt32();
      ReadTime(accessMask, item.LastAccessTime);
    }
  }

  UInt16 fileHeaderWithNameSize = (UInt16)m_CurPos;
  
  item.Position = m_Position;
  item.MainPartSize = fileHeaderWithNameSize;
  item.CommentSize = m_BlockHeader.HeadSize - fileHeaderWithNameSize;

  if (m_CryptoMode)
    item.AlignSize = (16 - ((m_BlockHeader.HeadSize) & 0xF)) & 0xF;
  else
    item.AlignSize = 0;
  AddToSeekValue(m_BlockHeader.HeadSize);
}

void CInArchive::AddToSeekValue(UInt64 addValue)
{
  m_Position += addValue;
}

HRESULT CInArchive::GetNextItem(CItemEx &item, ICryptoGetTextPassword *getTextPassword)
{
  if (m_SeekOnArchiveComment)
    SkipArchiveComment();
  while (true)
  {
    if(!SeekInArchive(m_Position))
      return S_FALSE;
    if (!m_CryptoMode && (m_ArchiveHeader.Flags & 
        NHeader::NArchive::kBlockHeadersAreEncrypted) != 0)
    {
      m_CryptoMode = false;
      if (getTextPassword == 0)
        return S_FALSE;
      if(!SeekInArchive(m_Position))
        return S_FALSE;
      if (!m_RarAES)
      {
        m_RarAESSpec = new NCrypto::NRar29::CDecoder;
        m_RarAES = m_RarAESSpec;
      }
      m_RarAESSpec->SetRar350Mode(m_ArchiveHeader.IsEncryptOld());

      // Salt
      const UInt32 kSaltSize = 8;
      Byte salt[kSaltSize];
      if(!ReadBytesAndTestSize(salt, kSaltSize))
        return false;
      m_Position += kSaltSize;
      RINOK(m_RarAESSpec->SetDecoderProperties2(salt, kSaltSize))
      // Password
      CMyComBSTR password;
      RINOK(getTextPassword->CryptoGetTextPassword(&password))
      UString unicodePassword(password);

      CByteBuffer buffer;
      const UInt32 sizeInBytes = unicodePassword.Length() * 2;
      buffer.SetCapacity(sizeInBytes);
      for (int i = 0; i < unicodePassword.Length(); i++)
      {
        wchar_t c = unicodePassword[i];
        ((Byte *)buffer)[i * 2] = (Byte)c;
        ((Byte *)buffer)[i * 2 + 1] = (Byte)(c >> 8);
      }

      RINOK(m_RarAESSpec->CryptoSetPassword((const Byte *)buffer, sizeInBytes));

      const UInt32 kDecryptedBufferSize = (1 << 12);
      if (m_DecryptedData.GetCapacity() == 0)
      {
        m_DecryptedData.SetCapacity(kDecryptedBufferSize);
      }
      RINOK(m_RarAES->Init());
      RINOK(ReadStream(m_Stream, (Byte *)m_DecryptedData, kDecryptedBufferSize, &m_DecryptedDataSize));
      m_DecryptedDataSize = m_RarAES->Filter((Byte *)m_DecryptedData, m_DecryptedDataSize);

      m_CryptoMode = true;
      m_CryptoPos = 0;
    }

    m_FileHeaderData.EnsureCapacity(7);
    if(!ReadBytesAndTestSize((Byte *)m_FileHeaderData, 7))
      return S_FALSE;

    m_CurData = (Byte *)m_FileHeaderData;
    m_CurPos = 0;
    m_PosLimit = 7;
    m_BlockHeader.CRC = ReadUInt16();
    m_BlockHeader.Type = ReadByte();
    m_BlockHeader.Flags = ReadUInt16();
    m_BlockHeader.HeadSize = ReadUInt16();

    if (m_BlockHeader.HeadSize < 7)
      ThrowExceptionWithCode(CInArchiveException::kIncorrectArchive);

    if (m_BlockHeader.Type == NHeader::NBlockType::kEndOfArchive) 
      return S_FALSE;

    if (m_BlockHeader.Type == NHeader::NBlockType::kFileHeader) 
    {
      m_FileHeaderData.EnsureCapacity(m_BlockHeader.HeadSize);
      m_CurData = (Byte *)m_FileHeaderData;
      m_PosLimit = m_BlockHeader.HeadSize;
      ReadBytesAndTestResult(m_CurData + m_CurPos, m_BlockHeader.HeadSize - 7);
      ReadHeaderReal(item); 
      if ((CCRC::CalculateDigest(m_CurData + 2, 
          m_BlockHeader.HeadSize - item.CommentSize - 2) & 0xFFFF) != m_BlockHeader.CRC)
        ThrowExceptionWithCode(CInArchiveException::kFileHeaderCRCError);

      FinishCryptoBlock();
      m_CryptoMode = false;
      SeekInArchive(m_Position); // Move Position to compressed Data;    
      AddToSeekValue(item.PackSize);  // m_Position points to next header;
      return S_OK;
    }
    if (m_CryptoMode && m_BlockHeader.HeadSize > (1 << 12))
      return E_FAIL; // it's for bad passwords
    if ((m_BlockHeader.Flags & NHeader::NBlock::kLongBlock) != 0)
    {
      m_FileHeaderData.EnsureCapacity(7 + 4);
      m_CurData = (Byte *)m_FileHeaderData;
      ReadBytesAndTestResult(m_CurData + m_CurPos, 4); // test it
      m_PosLimit = 7 + 4;
      UInt32 dataSize = ReadUInt32();
      AddToSeekValue(dataSize);
      if (m_CryptoMode && dataSize > (1 << 27))
        return E_FAIL; // it's for bad passwords
      m_CryptoPos = m_BlockHeader.HeadSize;
    }
    else
      m_CryptoPos = 0;
    AddToSeekValue(m_BlockHeader.HeadSize);
    FinishCryptoBlock();
    m_CryptoMode = false;
  }
}

void CInArchive::DirectGetBytes(void *data, UInt32 size)
{  
  ReadStream(m_Stream, data, size, NULL);
}

bool CInArchive::SeekInArchive(UInt64 position)
{
  UInt64 newPosition;
  m_Stream->Seek(position, STREAM_SEEK_SET, &newPosition);
  return newPosition == position;
}

ISequentialInStream* CInArchive::CreateLimitedStream(UInt64 position, UInt64 size)
{
  CLimitedSequentialInStream *streamSpec = new CLimitedSequentialInStream;
  CMyComPtr<ISequentialInStream> inStream(streamSpec);
  SeekInArchive(position);
  streamSpec->Init(m_Stream, size);
  return inStream.Detach();
}

}}