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Replace <sys/param.h> with <limits.h> and other less dirty headers where
possible.  Annotate <sys/param.h> lines with their current reasons.  Switch
to PATH_MAX, NGROUPS_MAX, HOST_NAME_MAX+1, LOGIN_NAME_MAX, etc.  Change
MIN() and MAX() to local definitions of MINIMUM() and MAXIMUM() where
sensible to avoid pulling in the pollution.  These are the files confirmed
through binary verification.
ok guenther, millert, doug (helped with the verification protocol)

/*	$OpenBSD: rcsnum.c,v 1.56 2015/01/16 06:40:07 deraadt Exp $	*/
/*
 * Copyright (c) 2004 Jean-Francois Brousseau <jfb@openbsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL  DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <ctype.h>
#include <string.h>

#include "cvs.h"

#define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))

static void	 rcsnum_setsize(RCSNUM *, u_int);
static char	*rcsnum_itoa(u_int16_t, char *, size_t);

/*
 * rcsnum_alloc()
 *
 * Allocate an RCS number structure and return a pointer to it.
 */
RCSNUM *
rcsnum_alloc(void)
{
	RCSNUM *rnp;

	rnp = xcalloc(1, sizeof(*rnp));
	rnp->rn_len = 0;

	return (rnp);
}

/*
 * rcsnum_addmagic()
 *
 * Adds a magic branch number to an RCS number.
 * Returns 0 on success, or -1 on failure.
 */
int
rcsnum_addmagic(RCSNUM *rn)
{
	if (!rn->rn_len || rn->rn_len > RCSNUM_MAXLEN - 1)
		return -1;
	rcsnum_setsize(rn, rn->rn_len + 1);
	rn->rn_id[rn->rn_len - 1] = rn->rn_id[rn->rn_len - 2];
	rn->rn_id[rn->rn_len - 2] = 0;

	return 0;
}

/*
 * rcsnum_parse()
 *
 * Parse a string specifying an RCS number and return the corresponding RCSNUM.
 */
RCSNUM *
rcsnum_parse(const char *str)
{
	char *ep;
	RCSNUM *num;

	num = rcsnum_alloc();
	if (rcsnum_aton(str, &ep, num) < 0 || *ep != '\0') {
		rcsnum_free(num);
		num = NULL;
	}

	return (num);
}

/*
 * rcsnum_free()
 *
 * Free an RCSNUM structure previously allocated with rcsnum_alloc().
 */
void
rcsnum_free(RCSNUM *rn)
{
	xfree(rn);
}

/*
 * rcsnum_tostr()
 *
 * Format the RCS number <nump> into a human-readable dot-separated
 * representation and store the resulting string in <buf>, which is of size
 * <blen>.
 * Returns a pointer to the start of <buf>.  On failure <buf> is set to
 * an empty string.
 */
char *
rcsnum_tostr(const RCSNUM *nump, char *buf, size_t blen)
{
	u_int i;
	char tmp[8];

	if (nump == NULL || nump->rn_len == 0) {
		buf[0] = '\0';
		return (buf);
	}

	if (strlcpy(buf, rcsnum_itoa(nump->rn_id[0], buf, blen), blen) >= blen)
		fatal("rcsnum_tostr: truncation");
	for (i = 1; i < nump->rn_len; i++) {
		const char *str;

		str = rcsnum_itoa(nump->rn_id[i], tmp, sizeof(tmp));
		if (strlcat(buf, ".", blen) >= blen ||
		    strlcat(buf, str, blen) >= blen)
			fatal("rcsnum_tostr: truncation");
	}
	return (buf);
}

static char *
rcsnum_itoa(u_int16_t num, char *buf, size_t len)
{
	u_int16_t i;
	char *p;

	if (num == 0)
		return "0";

	p = buf + len - 1;
	i = num;
	bzero(buf, len);
	while (i) {
		*--p = '0' + (i % 10);
		i  /= 10;
	}
	return (p);
}

/*
 * rcsnum_cpy()
 *
 * Copy the number stored in <nsrc> in the destination <ndst> up to <depth>
 * numbers deep.  If <depth> is 0, there is no depth limit.
 */
void
rcsnum_cpy(const RCSNUM *nsrc, RCSNUM *ndst, u_int depth)
{
	u_int len;

	len = nsrc->rn_len;
	if (depth != 0 && len > depth)
		len = depth;

	rcsnum_setsize(ndst, len);
	memcpy(ndst->rn_id, nsrc->rn_id, len * sizeof(*(nsrc->rn_id)));
}

/*
 * rcsnum_cmp()
 *
 * Compare the two numbers <n1> and <n2>. Returns -1 if <n1> is larger than
 * <n2>, 0 if they are both the same, and 1 if <n2> is larger than <n1>.
 * The <depth> argument specifies how many numbers deep should be checked for
 * the result.  A value of 0 means that the depth will be the maximum of the
 * two numbers, so that a longer number is considered greater than a shorter
 * number if they are equal up to the minimum length.
 */
int
rcsnum_cmp(RCSNUM *n1, RCSNUM *n2, u_int depth)
{
	int res;
	u_int i;
	size_t slen;

	if (!rcsnum_differ(n1, n2))
		return (0);

	slen = MINIMUM(n1->rn_len, n2->rn_len);
	if (depth != 0 && slen > depth)
		slen = depth;

	for (i = 0; i < slen; i++) {
		res = n1->rn_id[i] - n2->rn_id[i];
		if (res < 0)
			return (1);
		else if (res > 0)
			return (-1);
	}

	/* If an explicit depth was specified, and we've
	 * already checked up to depth, consider the
	 * revision numbers equal. */
	if (depth != 0 && slen == depth)
		return (0);
	else if (n1->rn_len > n2->rn_len)
		return (-1);
	else if (n2->rn_len > n1->rn_len)
		return (1);

	return (0);
}

/*
 * rcsnum_aton()
 *
 * Translate the string <str> containing a sequence of digits and periods into
 * its binary representation, which is stored in <nump>.  The address of the
 * first byte not part of the number is stored in <ep> on return, if it is not
 * NULL.
 * Returns 0 on success, or -1 on failure.
 */
int
rcsnum_aton(const char *str, char **ep, RCSNUM *nump)
{
	u_int32_t val;
	const char *sp;
	char *s;

	nump->rn_len = 0;
	nump->rn_id[0] = 0;

	for (sp = str;; sp++) {
		if (!isdigit((unsigned char)*sp) && (*sp != '.'))
			break;

		if (*sp == '.') {
			if (nump->rn_len >= RCSNUM_MAXLEN - 1)
				goto rcsnum_aton_failed;

			nump->rn_len++;
			nump->rn_id[nump->rn_len] = 0;
			continue;
		}

		val = (nump->rn_id[nump->rn_len] * 10) + (*sp - '0');
		if (val > RCSNUM_MAXNUM)
			fatal("RCSNUM overflow!");

		nump->rn_id[nump->rn_len] = val;
	}

	if (ep != NULL)
		*(const char **)ep = sp;

	/*
	 * Handle "magic" RCS branch numbers.
	 *
	 * What are they?
	 *
	 * Magic branch numbers have an extra .0. at the second farmost
	 * rightside of the branch number, so instead of having an odd
	 * number of dot-separated decimals, it will have an even number.
	 *
	 * Now, according to all the documentation I've found on the net
	 * about this, cvs does this for "efficiency reasons", I'd like
	 * to hear one.
	 *
	 * We just make sure we remove the .0. from in the branch number.
	 *
	 * XXX - for compatibility reasons with GNU cvs we _need_
	 * to skip this part for the 'log' command, apparently it does
	 * show the magic branches for an unknown and probably
	 * completely insane and not understandable reason in that output.
	 *
	 */
	if (nump->rn_len > 2 && nump->rn_id[nump->rn_len - 1] == 0) {
		/*
		 * Look for ".0.x" at the end of the branch number.
		 */
		if ((s = strrchr(str, '.')) != NULL) {
			s--;
			while (*s != '.')
				s--;

			/*
			 * If we have a "magic" branch, adjust it
			 * so the .0. is removed.
			 */
			if (!strncmp(s, RCS_MAGIC_BRANCH,
			    sizeof(RCS_MAGIC_BRANCH) - 1)) {
				nump->rn_id[nump->rn_len - 1] =
				    nump->rn_id[nump->rn_len];
				nump->rn_len--;
			}
		}
	}

	/* We can't have a single-digit rcs number. */
	if (nump->rn_len == 0) {
		nump->rn_len++;
		nump->rn_id[nump->rn_len] = 0;
	}

	nump->rn_len++;
	return (nump->rn_len);

rcsnum_aton_failed:
	nump->rn_len = 0;
	return (-1);
}

/*
 * rcsnum_inc()
 *
 * Increment the revision number specified in <num>.
 * Returns a pointer to the <num> on success, or NULL on failure.
 */
RCSNUM *
rcsnum_inc(RCSNUM *num)
{
	if (num->rn_id[num->rn_len - 1] == RCSNUM_MAXNUM)
		return (NULL);
	num->rn_id[num->rn_len - 1]++;
	return (num);
}

/*
 * rcsnum_dec()
 *
 * Decreases the revision number specified in <num>, if doing so will not
 * result in an ending value below 1. E.g. 4.2 will go to 4.1 but 4.1 will
 * be returned as 4.1.
 */
RCSNUM *
rcsnum_dec(RCSNUM *num)
{
	/* XXX - Is it an error for the number to be 0? */
	if (num->rn_id[num->rn_len - 1] <= 1)
		return (num);
	num->rn_id[num->rn_len - 1]--;
	return (num);
}

/*
 * rcsnum_revtobr()
 *
 * Retrieve the branch number associated with the revision number <num>.
 * If <num> is a branch revision, the returned value will be the same
 * number as the argument.
 */
RCSNUM *
rcsnum_revtobr(const RCSNUM *num)
{
	RCSNUM *brnum;

	if (num->rn_len < 2)
		return (NULL);

	brnum = rcsnum_alloc();
	rcsnum_cpy(num, brnum, 0);

	if (!RCSNUM_ISBRANCH(brnum))
		brnum->rn_len--;

	return (brnum);
}

/*
 * rcsnum_brtorev()
 *
 * Retrieve the initial revision number associated with the branch number <num>.
 * If <num> is a revision number, an error will be returned.
 */
RCSNUM *
rcsnum_brtorev(const RCSNUM *brnum)
{
	RCSNUM *num;

	if (!RCSNUM_ISBRANCH(brnum)) {
		return (NULL);
	}

	num = rcsnum_alloc();
	rcsnum_setsize(num, brnum->rn_len + 1);
	rcsnum_cpy(brnum, num, brnum->rn_len);
	num->rn_id[num->rn_len++] = 1;

	return (num);
}

RCSNUM *
rcsnum_new_branch(RCSNUM *rev)
{
	RCSNUM *branch;

	if (rev->rn_len > RCSNUM_MAXLEN - 1)
		return NULL;

	branch = rcsnum_alloc();
	rcsnum_cpy(rev, branch, 0);
	rcsnum_setsize(branch, rev->rn_len + 1);
	branch->rn_id[branch->rn_len - 1] = 2;

	return branch;
}

RCSNUM *
rcsnum_branch_root(RCSNUM *brev)
{
	RCSNUM *root;

	if (!RCSNUM_ISBRANCHREV(brev))
		fatal("rcsnum_branch_root: no revision on branch specified");

	root = rcsnum_alloc();
	rcsnum_cpy(brev, root, 0);
	root->rn_len -= 2;
	return (root);
}

static void
rcsnum_setsize(RCSNUM *num, u_int len)
{
	num->rn_len = len;
}

int
rcsnum_differ(RCSNUM *r1, RCSNUM *r2)
{
	int i, len;

	if (r1->rn_len != r2->rn_len)
		return (1);

	len = MINIMUM(r1->rn_len, r2->rn_len);
	for (i = 0; i < len; i++) {
		if (r1->rn_id[i] != r2->rn_id[i])
			return (1);
	}

	return (0);
}