我正在开发一个客户端服务器应用程序,其中客户端压缩发送到服务器的 2MB 数据,服务器接收数据将其解压缩并将其写入文件。
对于某些数据包解压缩失败,我将 MD5 和添加到客户端和服务器端代码,并在压缩数据后在客户端使用解压缩进行调试。在客户端传递给解压缩函数的相同参数在服务器端失败并出现 Z_DATA_ERROR。数据的 MD5sum 似乎相同。我完全不知道接下来我能做什么。
服务器端鳕鱼看起来像这样:
int ret = uncompress((Bytef*)unCompressedBuffer, &dwUncompressedBytes, (const Bytef*) receivedBuffer+525, dwBlockLength);
if (ret == Z_OK)
{
}
else
{
std::cout << " Uncompression failed for Block: " << iBlock << std::endl;
std::cout << " PacketType: 4" << " Block Number:" << iBlock << " Length:" << dwBlockLength << "Error:" << ret << std::endl;
PrintMD5SumResult((PBYTE)receivedBuffer+525, compressedSize-525);
std::cout << " Uncompressed MD5 Checksum:0";
PrintMD5SumResult((PBYTE)unCompressedBuffer, dwUncompressedBytes);
}
}
客户端代码如下所示:
int ret = compress2(l_pCompressData + 4, &destLen,
(const Bytef*) pBlockData, dwBlockSize, 6);
memcpy(m_pWriteBuffer+525, l_pCompressData, destLen);
m_dwWriteBytes = destLen+525;
std::cout << " \n Compressed MD5 Sum:0";
PrintMD5SumResult(m_pWriteBuffer, m_dwWriteBytes);
PrintMD5SumResult(m_pWriteBuffer+525, m_dwWriteBytes-525);
int ret = uncompress(m_pUnCompressData, &uncomLen, (const Bytef*)m_pWriteBuffer+525, destLen);
if(ret != Z_OK)
{
std::cout << " Uncompression has failed." << std::endl;
}
else
{
//std::cout << " UnCompressed MD5 Sum:0";
//PrintMD5SumResult((PBYTE)m_pUnCompressData, md5Output, dwBlockSize);
}
// Write the 2MB to the network
WriteDataOverNetwork(m_NetworkStream, m_pWriteBuffer, m_dwWriteBytes, &dwNumBytes, TRUE);
我将问题缩小到 zlib 中的以下代码段 - 但很难理解它。在 inflate() 函数中,(ZSWAP32(hold)) != state->check) 此语句失败。有人可以帮我吗?此处使用的 MD5sum 来自 Boton C++ 库。
case CHECK:
if (state->wrap) {
NEEDBITS(32);
out -= left;
strm->total_out += out;
state->total += out;
if (out)
strm->adler = state->check =
UPDATE(state->check, put - out, out);
out = left;
if ((
#ifdef GUNZIP
state->flags ? hold :
#endif
ZSWAP32(hold)) != state->check) {
strm->msg = (char *)"incorrect data check";
state->mode = BAD;
break;
}