text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2012 The Bitcoin developers
  // Distributed under the MIT/X11 software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "constants.h"
  #include "protocol.h"
  #include "util.h"
  #include "netbase.h"
  
  #ifndef WIN32
  # include <arpa/inet.h>
  #endif
  
  void GetMessageStart(unsigned char pchMessageStartStore[], bool fPersistent)
  {
      memcpy(pchMessageStartStore, PROTOCOL_MAGIC_BYTES, sizeof(PROTOCOL_MAGIC_BYTES));
  }
  
  static const char* ppszTypeName[] =
  {
      "ERROR",
      "tx",
      "block",
  };
  
  CMessageHeader::CMessageHeader()
  {
      GetMessageStart(pchMessageStart);
      memset(pchCommand, 0, sizeof(pchCommand));
      pchCommand[1] = 1;
      nMessageSize = -1;
      nChecksum = 0;
  }
  
  CMessageHeader::CMessageHeader(const char* pszCommand, unsigned int nMessageSizeIn)
  {
      GetMessageStart(pchMessageStart);
      strncpy(pchCommand, pszCommand, COMMAND_SIZE);
      nMessageSize = nMessageSizeIn;
      nChecksum = 0;
  }
  
  std::string CMessageHeader::GetCommand() const
  {
      if (pchCommand[COMMAND_SIZE-1] == 0)
          return std::string(pchCommand, pchCommand + strlen(pchCommand));
      else
          return std::string(pchCommand, pchCommand + COMMAND_SIZE);
  }
  
  bool CMessageHeader::IsValid() const
  {
      // Check start string
      unsigned char pchMessageStartProtocol[4];
      GetMessageStart(pchMessageStartProtocol);
      if (memcmp(pchMessageStart, pchMessageStartProtocol, sizeof(pchMessageStart)) != 0)
          return false;
  
      // Check the command string for errors
      for (const char* p1 = pchCommand; p1 < pchCommand + COMMAND_SIZE; p1++)
      {
          if (*p1 == 0)
          {
              // Must be all zeros after the first zero
              for (; p1 < pchCommand + COMMAND_SIZE; p1++)
                  if (*p1 != 0)
                      return false;
          }
          else if (*p1 < ' ' || *p1 > 0x7E)
              return false;
      }
  
      // Message size
      if (nMessageSize > MAX_SIZE)
      {
          printf("CMessageHeader::IsValid() : (%s, %u bytes) nMessageSize > MAX_SIZE\n", GetCommand().c_str(), nMessageSize);
          return false;
      }
  
      return true;
  }
  
  
  
  CAddress::CAddress() : CService()
  {
      Init();
  }
  
  CAddress::CAddress(CService ipIn, uint64 nServicesIn) : CService(ipIn)
  {
      Init();
      nServices = nServicesIn;
  }
  
  void CAddress::Init()
  {
      nServices = NODE_NETWORK;
      nTime = 100000000;
      nLastTry = 0;
  }
  
  CInv::CInv()
  {
      type = 0;
      hash = 0;
  }
  
  CInv::CInv(int typeIn, const uint256& hashIn)
  {
      type = typeIn;
      hash = hashIn;
  }
  
  CInv::CInv(const std::string& strType, const uint256& hashIn)
  {
      unsigned int i;
      for (i = 1; i < ARRAYLEN(ppszTypeName); i++)
      {
          if (strType == ppszTypeName[i])
          {
              type = i;
              break;
          }
      }
      if (i == ARRAYLEN(ppszTypeName))
          throw std::out_of_range(strprintf("CInv::CInv(string, uint256) : unknown type '%s'", strType.c_str()));
      hash = hashIn;
  }
  
  bool operator<(const CInv& a, const CInv& b)
  {
      return (a.type < b.type || (a.type == b.type && a.hash < b.hash));
  }
  
  bool CInv::IsKnownType() const
  {
      return (type >= 1 && type < (int)ARRAYLEN(ppszTypeName));
  }
  
  const char* CInv::GetCommand() const
  {
      if (!IsKnownType())
          throw std::out_of_range(strprintf("CInv::GetCommand() : type=%d unknown type", type));
      return ppszTypeName[type];
  }
  
  std::string CInv::ToString() const
  {
      return strprintf("%s %s", GetCommand(), hash.ToString().substr(0,20).c_str());
  }
  
  void CInv::print() const
  {
      printf("CInv(%s)\n", ToString().c_str());
  }
  