I'm not completely sure about that. The string does not have to be zero-terminated unless c_str() was called. At least I think so. It's a bit hot here.
According to cplusplus.com: "If pos is equal to the string length, the function returns a reference to a null character ('\0')."
Which seems like a sane definition.
Dude your code is an eye sore.
Eddie -- criticism is welcome if you're able to offer helpful advice on how a user might improve, or lacking that even if you can point out specific problems to be examined and improved upon. Posting just to insult someone's code without taking the time to help is neither helpful nor friendly, and even wastes the time of people reading the response. Please don't respond unless you actually have something to contribute.
Just a suggestion: If your goal is not to build a model parser, but just to load a model into memory so you can accomplish your actual goal, consider using: http://assimp.sourceforge.net/
