[utils] RegEx is slow (can we make faster hex functions?) #10208

Activity

1. davidmurdoch

   changed the title [-]RegEx is slow[/-] [+]RegEx is slow (can we make faster hex functions?)[/+] on Jul 8, 2025
2. davidmurdoch commented on Jul 8, 2025

   

   davidmurdoch

   on Jul 8, 2025

   ContributorAuthor

   More actions

   I got into some further optimizations:

   function isHexAddressCaseInsensitiveFast(str) {
     if (typeof str !== "string" || str.length !== 42) return false;
     if (str[0] !== '0' || str[1] !== 'x') return false;
   
     for (let i = 2; i < 42; i++) {
       // transform the character code for case-insensitivity
       const charCode = str.charCodeAt(i) & 0xDF;
   
       // after transformation, '0'-'9' are in the range 16-25
       const numberRange = (charCode - 16) | (25 - charCode);
       // after transformation, 'a'-'f' are in the range 65-70 ('A'-'F'), `A`-`F` remains unchanged
       const letterRange = (charCode - 65) | (70 - charCode);
   
       // identifies if the charCode is OUTSIDE of both valid ranges.
       if (((numberRange & letterRange) & 0x80000000) !== 0) {
         return false;
       }
     }
   
     return true;
   }
   

   for a 50% spread of 1000000 valid/invalid mix-cased strings the runtimes are:

   isHexAddressCaseInsensitive: 238.701ms (uses `HEX_CHECKSUM_ADDRESS_REGEX`)
   isHexAddressCaseInsensitiveFast: 50.609ms

   Ok, I'm going to stop now. Use bitwise responsibly. :-)
3. mcmire commented on Jul 9, 2025

   

   mcmire

   on Jul 9, 2025

   Collaborator

   More actions

   @davidmurdoch I thought your view was that these changes to the hex functions were in the end micro-optimizations? Do you think it's still worth it to optimize them further?
4. cryptodev-2s

   changed the title [-]RegEx is slow (can we make faster hex functions?)[/-] [+][utils] RegEx is slow (can we make faster hex functions?)[/+] on Sep 11, 2026
5. cryptodev-2s

   transferred this issue fromMetaMask/utilson Sep 11, 2026