ref: b02b5fd160095f12c706e8b731bcc1feb6855d58
dir: /src/libc/stdlib/_dtoi.c/
#include <ctype.h> #include <limits.h> #include <string.h> int _dtoi(char c) { static const char digits[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; char *p; if (p = strchr(digits, toupper(c))) return p - digits; return INT_MAX; }