/*-*- 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];
}
