Infinite loop in makeobj.

Topic: Infinite loop in makeobj. (Read 5890 times) previous topic - next topic

Infinite loop in makeobj.

September 18, 2010, 11:15:42 am

Something wrong with folowing code (besch/writer/vehicle_writer.cc)

        uint8 upgrades = 0;
        do {
                char buf[40];
                sprintf(buf, "upgrade[%d]", upgrades);
                str = obj.get(buf);
                found = str.size() > 0;
                if (found)
                {
                        if (upgrades == 0 && !STRICMP(str.c_str(), "none"))
                        {
                                if (!STRICMP(str.c_str(), "none"))
                                {
                                        str = "";
                                }
                                xref_writer_t::instance()->write_obj(fp, node, obj_vehicle, str.c_str(), false);
                                upgrades++;
                        }
                }
        } while (found);

!STRICMP(str.c_str(), "none") == false for first iteration so upgrades never incremented and we have infinite loop.

Re: Infinite loop in makeobj.

Reply #1 – September 18, 2010, 09:18:48 pm

Thank you for pointing this out. Would this be an appropriate fix, do you think?

Code: [Select]

// Upgrades: these are the vehicle types to which this vehicle
	// can be upgraded. "None" means that it cannot be upgraded. 
	// @author: jamespetts
	uint8 upgrades = 0;
	do {
		char buf[40];
		sprintf(buf, "upgrade[%d]", upgrades);
		str = obj.get(buf);
		found = str.size() > 0;
		if (found) 
		{
			if (upgrades == 0 && !STRICMP(str.c_str(), "none")) 
			{
				if (!STRICMP(str.c_str(), "none")) 
				{
					str = "";
				}
				xref_writer_t::instance()->write_obj(fp, node, obj_vehicle, str.c_str(), false);
			}
			upgrades++;
		}
	} while (found);

Re: Infinite loop in makeobj.

Reply #2 – September 18, 2010, 09:27:07 pm

It is merge error, i think.
I don't really understand why we need check for upgrades == 0 and why !STRICMP(str.c_str(), "none") checked twice.

just

Code: [Select]

        uint8 upgrades = 0;
        do {
                char buf[40];
                sprintf(buf, "upgrade[%d]", upgrades);
                str = obj.get(buf);
                found = str.size() > 0;
                if (found)
                {
                        if (!STRICMP(str.c_str(), "none"))
                        {
                                str = "";
                        }
                        else
                        {   
                                xref_writer_t::instance()->write_obj(fp, node, obj_vehicle, str.c_str(), false);
                                upgrades++;
                        }
                }
        } while (found);

will be fine?

Re: Infinite loop in makeobj.

Reply #3 – September 18, 2010, 09:34:20 pm

That looks very different - I must confess, I can't remember precisely how the code was intended now (and, yes, I think that you're right that it was a merge error). Have you tested your version?

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Infinite loop in makeobj.

September 18, 2010, 11:15:42 am

Re: Infinite loop in makeobj.

Reply #1 – September 18, 2010, 09:18:48 pm

Re: Infinite loop in makeobj.

Reply #2 – September 18, 2010, 09:27:07 pm

Re: Infinite loop in makeobj.

Reply #3 – September 18, 2010, 09:34:20 pm

Re: Infinite loop in makeobj.

Reply #4 – September 18, 2010, 09:35:41 pm

Re: Infinite loop in makeobj.

Reply #5 – September 18, 2010, 10:15:15 pm