/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8   -*-│
│vi: set et ft=c ts=8 tw=8 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\"");
// clang-format off

/**
 * 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]-'1'<9U && r[dp]-'1'<9U) {
		/* If we're looking at non-degenerate digit sequences starting
		 * with nonzero digits, 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];
}