ref: 36af8405521be371605e4658ec8f4b133f3c7d6f dir: /sys/src/ape/lib/ap/gen/toupper.c/
#include <ctype.h> 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'); }