cosmopolitan/libc/fmt/strtoul.c
Justine Tunney 68c7c9c1e0
Clean up some code
- Use good ELF technique in cosmo_dlopen()
- Make strerror() conform more to other libc impls
- Introduce __clear_cache() and use it in cosmo_dlopen()
- Remove libc/fmt/fmt.h header (trying to kill off LIBC_FMT)
2023-11-16 17:31:07 -08:00

69 lines
3.3 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/errno.h"
#include "libc/fmt/conv.h"
#include "libc/fmt/internal.h"
#include "libc/limits.h"
#include "libc/stdckdint.h"
#include "libc/str/str.h"
#include "libc/str/tab.internal.h"
/**
* Decodes unsigned integer from ASCII string.
*
* @param s is a non-null nul-terminated string
* @param endptr if non-null will always receive a pointer to the char
* following the last one this function processed, which is usually
* the NUL byte, or in the case of invalid strings, would point to
* the first invalid character
* @param base can be anywhere between [2,36] or 0 to auto-detect based
* on the the prefixes 0 (octal), 0x (hexadecimal), 0b (binary), or
* decimal (base 10) by default
* @return decoded integer mod 2⁶⁴ negated if leading `-`
* @raise ERANGE on overflow
*/
unsigned long strtoul(const char *s, char **endptr, int base) {
char t = 0;
int d, c = *s;
unsigned long x = 0;
CONSUME_SPACES(char, s, c);
GET_SIGN(s, c, d);
GET_RADIX(s, c, base);
if ((c = kBase36[c & 255]) && --c < base) {
t |= 1;
do {
if (ckd_mul(&x, x, base) || ckd_add(&x, x, c)) {
if (endptr) {
*endptr = (char *)(s + 1);
}
errno = ERANGE;
return ULONG_MAX;
}
} while ((c = kBase36[*++s & 255]) && --c < base);
}
if (t && endptr) {
*endptr = (char *)s;
}
return d > 0 ? x : -x;
}
__weak_reference(strtoul, strtoumax);
__weak_reference(strtoul, strtoull);
__weak_reference(strtoul, strtoull_l);