ref: 12ccbe2af48585937a4bc80c6e559b9617c6aac6
dir: /src/libc/stdlib/strtol.c/
#include <ctype.h> #include <errno.h> #include <limits.h> #include <stdlib.h> #include <string.h> #include "../libc.h" #undef strtol long strtol(const char * restrict s, char ** restrict end, int base) { int d, sign = -1; 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; /* Compute n as a negative number to avoid overflow on LONG_MIN */ for (t = s; (d = _dtoi(*t)) < base; ++t) { if (n < LONG_MIN/base) goto overflow; n *= base; if (-d < LONG_MIN - n) goto overflow; n -= d; if (n == LONG_MIN && sign < 0) goto overflow; } if (end && t != s) *end = t; return n*sign; overflow: if (end) *end = t; errno = ERANGE; return sign < 0 ? LONG_MAX : LONG_MIN; }