source: azure_iot_hub/trunk/musl-1.1.18/src/stdlib/strtol.c@ 388

#include "stdio_impl.h"
#include "intscan.h"
#include "shgetc.h"
#include <inttypes.h>
#include <limits.h>
#include <ctype.h>
#include "libc.h"

static unsigned long long strtox(const char *s, char **p, int base, unsigned long long lim)
{
        /* FIXME: use a helper function or macro to setup the FILE */
        FILE f;
        f.flags = 0;
        f.buf = f.rpos = (void *)s;
        if ((size_t)s > (size_t)-1/2)
                f.rend = (void *)-1;
        else
                f.rend = (unsigned char *)s+(size_t)-1/2;
        f.lock = -1;
        shlim(&f, 0);
        unsigned long long y = __intscan(&f, base, 1, lim);
        if (p) {
                size_t cnt = shcnt(&f);
                *p = (char *)s + cnt;
        }
        return y;
}

unsigned long long strtoull(const char *restrict s, char **restrict p, int base)
{
        return strtox(s, p, base, ULLONG_MAX);
}

long long strtoll(const char *restrict s, char **restrict p, int base)
{
        return strtox(s, p, base, LLONG_MIN);
}

unsigned long strtoul(const char *restrict s, char **restrict p, int base)
{
        return strtox(s, p, base, ULONG_MAX);
}

long strtol(const char *restrict s, char **restrict p, int base)
{
        return strtox(s, p, base, 0UL+LONG_MIN);
}

intmax_t strtoimax(const char *restrict s, char **restrict p, int base)
{
        return strtoll(s, p, base);
}

uintmax_t strtoumax(const char *restrict s, char **restrict p, int base)
{
        return strtoull(s, p, base);
}

weak_alias(strtol, __strtol_internal);
weak_alias(strtoul, __strtoul_internal);
weak_alias(strtoll, __strtoll_internal);
weak_alias(strtoull, __strtoull_internal);
weak_alias(strtoimax, __strtoimax_internal);
weak_alias(strtoumax, __strtoumax_internal);