ref: 8eca9474c47d3898aa44e8e1879eda8a77fa6194 dir: /libkern/toupper.c/
toupper(int c) { if(c < 'a' || c > 'z') return c; return (c-'a'+'A'); } tolower(int c) { if(c < 'A' || c > 'Z') return c; return (c-'A'+'a'); }