ref: db565b93a3e8db0e72be663d3cb6560ab96fc64f
dir: /src/libc/stdlib/strtoull.c/
#include <ctype.h> #include <errno.h> #include <limits.h> #include <stdlib.h> #include <string.h> #include "../libc.h" #undef strtoull unsigned long long strtoull(const char * restrict s, char ** restrict end, int base) { int d, sign = 1; unsigned long long n; const char *t; if (end) *end = s; while (isspace(*s)) ++s; switch (*s) { case '-': sign = -1; case '+': ++s; } if (base == 0) { if (*s == '0') base = toupper(s[1]) == 'X' ? 16 : 8; else base = 10; } if (base == 16 && *s == '0' && toupper(s[1]) == 'X') s += 2; n = 0; for (t = s; (d = _dtoi(*t)) < base; ++t) { if (n > ULLONG_MAX/base) goto overflow; n *= base; if (d > ULLONG_MAX - n) goto overflow; n += d; } if (end && t != s) *end = t; return n*sign; overflow: if (end) *end = t; errno = ERANGE; return ULLONG_MAX; }