// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2011 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file license.txt or http://www.opensource.org/licenses/mit-license.php.

#include "protocol.h"

CMessageHeader::CMessageHeader()
{
    memcpy(pchMessageStart, ::pchMessageStart, sizeof(pchMessageStart));
    memset(pchCommand, 0, sizeof(pchCommand));
    pchCommand[1] = 1;
    nMessageSize = -1;
    nChecksum = 0;
}

CMessageHeader::CMessageHeader(const char* pszCommand, unsigned int nMessageSizeIn)
{
    memcpy(pchMessageStart, ::pchMessageStart, sizeof(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
    if (memcmp(pchMessageStart, ::pchMessageStart, 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;
}