[OT] parsing with sscanf is accidentally quadratic due to strlen

[Patrick Schluter]

On Wednesday, 3 March 2021 at 09:12:19 UTC, Kagamin wrote:
> Parsers based on sscanf choke on big strings: 
> https://nee.lv/2021/02/28/How-I-cut-GTA-Online-loading-times-by-70/
> Source: 
> https://github.com/chakra-core/ChakraCore/blob/master/pal/src/safecrt/sscanf.c#L47

Yes, sscanf() calls strlen(). I got bitten by it also some years 
ago when I memory mapped some log files to parse and had the my 
program hog the CPU when I went in production. On my test files 
that were not that big, memory mapping and changing fscanf() to 
sscanf() was a no brainer. When it went in production and started 
to map megabytes or gigabyte sized files, I rediscovered what a 
O(n²) algorithm looked like...