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Parsing Integers in C

42 points by 8organicbits

by piker

5 subcomments

"I think we in the curl project as well as more or less the entire world has learned through the years that it is usually better to be strict when parsing protocols and data, rather than be lenient and try to accept many things and guess what it otherwise maybe meant."
Found this explicit rejection of the Robustness principle[1] fascinating. It comes after decades of cURL operating in the environment that was an ostensible poster child for the benefits of the principle--i.e., HTML over HTTP.
[1] https://en.wikipedia.org/wiki/Robustness_principle

by johnisgood

0 subcomment

Quick link to the code: https://github.com/curl/curl/blob/3d42510118a9eba12a0d3cd4e2...

by Joker_vD

1 subcomments

The strtoul()/strtoull() also have a somewhat strange semantics regarding the leading '-': it will apply it to the (unsigned) result, so e.g strtoul("-40", ...) happily returns 18446744073709551576.
Also, the wording of the standard suggests that using strtol()/strtoll() to parse the string representation of LONG_MIN/LLONG_MIN is UB, since it kinda has to go through un-negated LONG_MAX+1/LLONG_MAX+1 which can't be represented in the return type?