C++ string::assign方法代码示例

void ExecuteStatement::getString(thread_db* tdbb,
                                 Firebird::string& sql,
                                 const dsc* desc,
                                 const jrd_req* request)
{
    MoveBuffer buffer;

    UCHAR* ptr = NULL;

    const SSHORT len = (desc && !(request->req_flags & req_null)) ?
                       MOV_make_string2(tdbb, desc, desc->getTextType(), &ptr, buffer) : 0; // !!! How call Msgs ?

    if (!ptr)
    {
        ERR_post(Arg::Gds(isc_exec_sql_invalid_arg));
    }

    sql.assign((const char*) ptr, len);
}

//***************
// r e a d e n v
//***************
// Goes to read directly the environment variables from the operating system on Windows
// and provides a stub for UNIX.
bool readenv(const char* env_name, Firebird::string& env_value)
{
#ifdef WIN_NT
	const DWORD rc = GetEnvironmentVariable(env_name, NULL, 0);
	if (rc)
	{
		env_value.reserve(rc - 1);
		DWORD rc2 = GetEnvironmentVariable(env_name, env_value.begin(), rc);
		if (rc2 < rc && rc2 != 0)
		{
			env_value.recalculate_length();
			return true;
		}
	}
#else
	const char* p = getenv(env_name);
	if (p)
		return env_value.assign(p).length() != 0;
#endif
	// Not found, clear the output var.
	env_value.begin()[0] = 0;
	env_value.recalculate_length();
	return false;
}

void exactNumericToStr(SINT64 value, int scale, Firebird::string& target, bool append)
{
	if (value == 0)
	{
		if (append)
			target.append("0", 1);
		else
			target.assign("0", 1);
		return;
	}

	const int MAX_SCALE = 25;
	const int MAX_BUFFER = 50;

	if (scale < -MAX_SCALE || scale > MAX_SCALE)
	{
		fb_assert(false);
		return; // throw exception here?
	}

	const bool neg = value < 0;
	const bool dot = scale < 0; // Need the decimal separator or not?
	char buffer[MAX_BUFFER];
	int iter = MAX_BUFFER;

	buffer[--iter] = '\0';

	if (scale > 0)
	{
		while (scale-- > 0)
			buffer[--iter] = '0';
	}

	bool dot_used = false;
	FB_UINT64 uval = neg ? FB_UINT64(-(value + 1)) + 1 : value; // avoid problems with MIN_SINT64

	while (uval != 0)
	{
		buffer[--iter] = static_cast<char>(uval % 10) + '0';
		uval /= 10;

		if (dot && !++scale)
		{
			buffer[--iter] = '.';
			dot_used = true;
		}
	}

	if (dot)
	{
		// if scale > 0 we have N.M
		// if scale == 0 we have .M and we need 0.M
		// if scale < 0 we have pending zeroes and need 0.{0+}M
		if (!dot_used)
		{
			while (scale++ < 0)
				buffer[--iter] = '0';

			buffer[--iter] = '.';
			buffer[--iter] = '0';
		}
		else if (!scale)
			buffer[--iter] = '0';
	}

	if (neg)
		buffer[--iter] = '-';

	const FB_SIZE_T len = MAX_BUFFER - iter - 1;

	if (append)
		target.append(buffer + iter, len);
	else
		target.assign(buffer + iter, len);
}

/**

	typeBuffer

	@brief	Prints data, returned by service, using outputFunction


	@param status
	@param buf
	@param offset
	@param uData
	@param outputFunction
	@param functionArg
	@param text

 **/
static int typeBuffer(ISC_STATUS* status, char* buf, int offset,
					   Auth::UserData& uData, Firebird::IListUsers* callback,
					   Firebird::string& text)
{
	const char* p = &buf[offset];

	// Sanity checks
	if (*p++ != isc_info_svc_get_users)
	{
	    status[0] = isc_arg_gds;
	    status[1] = isc_gsec_params_not_allowed;
		status[2] = isc_arg_end;
		return -1;
	}
	FB_SIZE_T loop = static_cast<FB_SIZE_T>(isc_vax_integer (p, sizeof (USHORT)));
	p += sizeof (USHORT);
    if (p[loop] != isc_info_end)
	{
	    status[0] = isc_arg_gds;
	    status[1] = isc_gsec_params_not_allowed;
		status[2] = isc_arg_end;
		return -1;
	}

	// No data - stop processing
	if (! loop)
	{
		return -1;
	}

	// Old data left - use them
	if (offset)
	{
		memmove(&buf[offset], p, loop + 1);
		p = buf;
		loop += offset;
		offset = 0;
	}

	while (*p != isc_info_end)
	{
		fb_assert(p[loop] == isc_info_end);
		try
		{
			switch (*p++)
			{
			case isc_spb_sec_username:
				if (uData.user.get()[0])
				{
					LocalStatus status;
					CheckStatusWrapper statusWrapper(&status);

					if (callback)
					{
						setAttr(&statusWrapper, &uData);
						check(&statusWrapper);
						callback->list(&statusWrapper, &uData);
						check(&statusWrapper);
					}
					uData.clear(&statusWrapper);
					check(&statusWrapper);
				}
				parseString2(p, uData.user, loop);
				break;
			case isc_spb_sec_firstname:
				parseString2(p, uData.first, loop);
				break;
			case isc_spb_sec_middlename:
				parseString2(p, uData.middle, loop);
				break;
			case isc_spb_sec_lastname:
				parseString2(p, uData.last, loop);
				break;
			case isc_spb_sec_groupid:
				parseLong(p, uData.g, loop);
				break;
			case isc_spb_sec_userid:
				parseLong(p, uData.u, loop);
				break;
			case isc_spb_sec_admin:
				parseLong(p, uData.adm, loop);
				break;
			default:	// give up - treat it as gsec error
				text.assign(p - 1, loop + 1);
//.........这里部分代码省略.........