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 https://opensource.org/licenses/mit-license.php.
  
  #include "chainparams.h"
  #include "netbase.h"
  #include "protocol.h"
  #include "util.h"
  
  #ifndef WIN32
  # include <arpa/inet.h>
  #endif
  
  static const char* ppszTypeName[] =
  {
      "ERROR",
      "tx",
      "block",
      "part",
      "scraperindex",
  };
  
  CMessageHeader::CMessageHeader(const char* pszCommand, unsigned int nMessageSizeIn)
  {
      memcpy(pchMessageStart, Params().MessageStart(), CMessageHeader::MESSAGE_START_SIZE);
  
      // Copy the command name
      size_t i = 0;
      for (; i < COMMAND_SIZE && pszCommand[i] != 0; ++i) pchCommand[i] = pszCommand[i];
      assert(pszCommand[i] == 0); // Assert that the command name passed in is not longer than COMMAND_SIZE
  
      nMessageSize = nMessageSizeIn;
  }
  
  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
      if (memcmp(pchMessageStart, Params().MessageStart(), CMessageHeader::MESSAGE_START_SIZE) != 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)
      {
          LogPrintf("CMessageHeader::IsValid() : (%s, %u bytes) nMessageSize > MAX_SIZE", GetCommand(), nMessageSize);
          return false;
      }
  
      return true;
  }
  
  CInv::CInv()
  {
      type = 0;
      hash.SetNull();
  }
  
  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 < std::size(ppszTypeName); i++)
      {
          if (strType == ppszTypeName[i])
          {
              type = i;
              break;
          }
      }
      if (i == std::size(ppszTypeName))
          throw std::out_of_range(strprintf("CInv::CInv(string, uint256) : unknown type '%s'", strType));
      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)std::size(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));
  }
  
  void CInv::print() const
  {
      LogPrintf("CInv(%s)", ToString());
  }
  
  