cosmopolitan/libc/str/strverscmp.c
2021-01-27 19:34:02 -08:00

71 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│
╚──────────────────────────────────────────────────────────────────────────────╝
│ │
│ Musl Libc │
│ Copyright © 2005-2014 Rich Felker, et al. │
│ │
│ Permission is hereby granted, free of charge, to any person obtaining │
│ a copy of this software and associated documentation files (the │
│ "Software"), to deal in the Software without restriction, including │
│ without limitation the rights to use, copy, modify, merge, publish, │
│ distribute, sublicense, and/or sell copies of the Software, and to │
│ permit persons to whom the Software is furnished to do so, subject to │
│ the following conditions: │
│ │
│ The above copyright notice and this permission notice shall be │
│ included in all copies or substantial portions of the Software. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
│ │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/str/str.h"
asm(".ident\t\"\\n\\n\
Musl libc (MIT License)\\n\
Copyright 2005-2014 Rich Felker, et. al.\"");
asm(".include \"libc/disclaimer.inc\"");
/**
* Compares two version strings.
*/
int strverscmp(const char *l0, const char *r0) {
const unsigned char *l = (const void *)l0;
const unsigned char *r = (const void *)r0;
size_t i, dp, j;
int z = 1;
/* Find maximal matching prefix and track its maximal digit
* suffix and whether those digits are all zeros. */
for (dp = i = 0; l[i] == r[i]; i++) {
int c = l[i];
if (!c) return 0;
if (!isdigit(c)) {
dp = i + 1, z = 1;
} else if (c != '0') {
z = 0;
}
}
if (l[dp] != '0' && r[dp] != '0') {
/* If we're not looking at a digit sequence that began
* with a zero, longest digit string is greater. */
for (j = i; isdigit(l[j]); j++) {
if (!isdigit(r[j])) {
return 1;
}
}
if (isdigit(r[j])) {
return -1;
}
} else if (z && dp < i && (isdigit(l[i]) || isdigit(r[i]))) {
/* Otherwise, if common prefix of digit sequence is
* all zeros, digits order less than non-digits. */
return (unsigned char)(l[i] - '0') - (unsigned char)(r[i] - '0');
}
return l[i] - r[i];
}