Shouldn't you use tokSuper here?

[martinus]

jsmn/jsmn.c

Line 209 in 3508659

for (i = parser->toknext - 1; i >= 0; i--) {

I think at this position you can use tokSuper, which should save you from iterating the array at this point:

for (i = parser->tokSuper; i >= 0; i--) {

This should speed the parser up a bit.