cosmopolitan/libc/fmt/sizetol.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

106 lines
3.8 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 2021 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/fmt/conv.h"
#include "libc/stdckdint.h"
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"
static int GetExponent(int c) {
switch (c) {
case '\0':
case ' ':
case '\t':
return 0;
case 'k':
case 'K':
return 1;
case 'm':
case 'M':
return 2;
case 'g':
case 'G':
return 3;
case 't':
case 'T':
return 4;
case 'p':
case 'P':
return 5;
case 'e':
case 'E':
return 6;
default:
return -1;
}
}
/**
* Converts size string to long.
*
* The following unit suffixes may be used
*
* - `k` or `K` for kilo (multiply by 𝑏¹)
* - `m` or `M` for mega (multiply by 𝑏²)
* - `g` or `G` for giga (multiply by 𝑏³)
* - `t` or `T` for tera (multiply by 𝑏⁴)
* - `p` or `P` for peta (multiply by 𝑏⁵)
* - `e` or `E` for exa (multiply by 𝑏⁶)
*
* If a permitted alpha character is supplied, then any additional
* characters after it (e.g. kbit, Mibit, TiB) are ignored. Spaces
* before the integer are ignored, and overflows will be detected.
*
* Negative numbers are permissible, as well as a leading `+` sign. To
* tell the difference between an error return and `-1` you must clear
* `errno` before calling and test whether it changed.
*
* @param s is non-null nul-terminated input string
* @param b is multiplier which should be 1000 or 1024
* @return size greater than or equal 0 or -1 on error
* @error EINVAL if error is due to bad syntax
* @error EOVERFLOW if error is due to overflow
*/
long sizetol(const char *s, long b) {
long x;
int c, e, d;
do {
c = *s++;
} while (c == ' ' || c == '\t');
d = c == '-' ? -1 : 1;
if (c == '-' || c == '+') c = *s++;
if (!isdigit(c)) {
return einval();
}
x = 0;
do {
if (ckd_mul(&x, x, 10) || ckd_add(&x, x, (c - '0') * d)) {
return eoverflow();
}
} while (isdigit((c = *s++)));
if ((e = GetExponent(c)) == -1) {
return einval();
}
while (e--) {
if (ckd_mul(&x, x, b)) {
return eoverflow();
}
}
return x;
}