Create separate evmc::hex library for hex encoding/decoding

[chfast]

No description provided.

[gumb0]

I'm reading intro to std::error_code at http://blog.think-async.com/2010/04/system-error-support-in-c0x-part-4.html and I think public function const std::error_category& hex_category() is going to be needed, for the user to be able to check e.code().category() == evmc::hex_category().

[gumb0]

Hm why do you want to allow whitespace? If this is to skip extra whitespace from command line, it's better to handle it in command line code.

Also currently it looks to allow "0x12" and " 12" (also "0x 12" and "1 2"), but not " 0x12"

[chfast]

Yes, this is what I want for simplicity. This is useful for loading hex from files to get rid of line breaks.

[gumb0]

Just hex.erase(std::remove_if(hex.begin(), hex.end()), std::isspace), hex.end()) them!

[chfast]

This will not work with input iterators (planned change). In the end we can have hex_decoding_iterator and strip_whitespace_iterator but I think having just one is simpler.

[gumb0]

"valarray helper functions are almost entirely useless" ? http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253

[chfast]

http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#253