Memory leaks

[ptoomey3]

I'm not terribly familiar with the uthash library, but it looks like the way UT_string is being used is leaking memory in several locations. For example, there are a number of places that call ustring_new and never call ustring_free to free the underlying struct:

• https://github.com/gjtorikian/mtex2MML/blob/a9b1517f46dfda7922e2d2d955c95f23c22b5c5f/src/parse_extras.c#L266 - This calls ustring_new without ever calling ustring_free. The underlying char * is returned to the caller and the actual UT_string is left to leak memory. For example, in https://github.com/gjtorikian/mtex2MML/blob/a9b1517f46dfda7922e2d2d955c95f23c22b5c5f/src/parse_extras.c#L286 the underlying char * is returned to the caller. The caller then frees that string in https://github.com/gjtorikian/mtex2MML/blob/a9b1517f46dfda7922e2d2d955c95f23c22b5c5f/src/mtex2MML.y#L2514. But, that doesn't free the entire UT_string struct. The actual struct is composed of the underlying char * data as well as some additional metadata: https://github.com/gjtorikian/mtex2MML/blob/a9b1517f46dfda7922e2d2d955c95f23c22b5c5f/src/deps/uthash/utstring.h#L43-L47. ustring_free makes sure to free the char * as well as the memory allocated for the struct itself.
• https://github.com/gjtorikian/mtex2MML/blob/a9b1517f46dfda7922e2d2d955c95f23c22b5c5f/src/parse_extras.c#L305 - ustring_new without ustring_free. This one does a dupe, so it should be safe to free the original string.
• https://github.com/gjtorikian/mtex2MML/blob/a9b1517f46dfda7922e2d2d955c95f23c22b5c5f/src/parse_extras.c#L208 - usring_new without ustring_free. This one is similar to the original example, where the underling char * is returned without ever deleting the original UT_string.

So, it seems like all of these locations should dupe the char* returned from ustring_body so that the actual UT_string can be freed using ustring_free before the function returns.

[ptoomey3]

Nice.