1/*	$OpenBSD: rcsnum.c,v 1.59 2017/08/28 19:33:20 otto Exp $	*/
2/*
3 * Copyright (c) 2004 Jean-Francois Brousseau <jfb@openbsd.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. The name of the author may not be used to endorse or promote products
13 *    derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
16 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
17 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
18 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL  DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
21 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
23 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <ctype.h>
28#include <stdlib.h>
29#include <string.h>
30
31#include "cvs.h"
32
33#define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
34
35static void	 rcsnum_setsize(RCSNUM *, u_int);
36static char	*rcsnum_itoa(u_int16_t, char *, size_t);
37
38/*
39 * rcsnum_alloc()
40 *
41 * Allocate an RCS number structure and return a pointer to it.
42 */
43RCSNUM *
44rcsnum_alloc(void)
45{
46	RCSNUM *rnp;
47
48	rnp = xcalloc(1, sizeof(*rnp));
49	rnp->rn_len = 0;
50
51	return (rnp);
52}
53
54/*
55 * rcsnum_addmagic()
56 *
57 * Adds a magic branch number to an RCS number.
58 * Returns 0 on success, or -1 on failure.
59 */
60int
61rcsnum_addmagic(RCSNUM *rn)
62{
63	if (!rn->rn_len || rn->rn_len > RCSNUM_MAXLEN - 1)
64		return -1;
65	rcsnum_setsize(rn, rn->rn_len + 1);
66	rn->rn_id[rn->rn_len - 1] = rn->rn_id[rn->rn_len - 2];
67	rn->rn_id[rn->rn_len - 2] = 0;
68
69	return 0;
70}
71
72/*
73 * rcsnum_parse()
74 *
75 * Parse a string specifying an RCS number and return the corresponding RCSNUM.
76 */
77RCSNUM *
78rcsnum_parse(const char *str)
79{
80	const char *ep;
81	RCSNUM *num;
82
83	num = rcsnum_alloc();
84	if (rcsnum_aton(str, &ep, num) < 0 || *ep != '\0') {
85		free(num);
86		num = NULL;
87	}
88
89	return (num);
90}
91
92/*
93 * rcsnum_tostr()
94 *
95 * Format the RCS number <nump> into a human-readable dot-separated
96 * representation and store the resulting string in <buf>, which is of size
97 * <blen>.
98 * Returns a pointer to the start of <buf>.  On failure <buf> is set to
99 * an empty string.
100 */
101char *
102rcsnum_tostr(const RCSNUM *nump, char *buf, size_t blen)
103{
104	u_int i;
105	char tmp[8];
106
107	if (nump == NULL || nump->rn_len == 0) {
108		buf[0] = '\0';
109		return (buf);
110	}
111
112	if (strlcpy(buf, rcsnum_itoa(nump->rn_id[0], buf, blen), blen) >= blen)
113		fatal("rcsnum_tostr: truncation");
114	for (i = 1; i < nump->rn_len; i++) {
115		const char *str;
116
117		str = rcsnum_itoa(nump->rn_id[i], tmp, sizeof(tmp));
118		if (strlcat(buf, ".", blen) >= blen ||
119		    strlcat(buf, str, blen) >= blen)
120			fatal("rcsnum_tostr: truncation");
121	}
122	return (buf);
123}
124
125static char *
126rcsnum_itoa(u_int16_t num, char *buf, size_t len)
127{
128	u_int16_t i;
129	char *p;
130
131	if (num == 0)
132		return "0";
133
134	p = buf + len - 1;
135	i = num;
136	bzero(buf, len);
137	while (i) {
138		*--p = '0' + (i % 10);
139		i  /= 10;
140	}
141	return (p);
142}
143
144/*
145 * rcsnum_cpy()
146 *
147 * Copy the number stored in <nsrc> in the destination <ndst> up to <depth>
148 * numbers deep.  If <depth> is 0, there is no depth limit.
149 */
150void
151rcsnum_cpy(const RCSNUM *nsrc, RCSNUM *ndst, u_int depth)
152{
153	u_int len;
154
155	len = nsrc->rn_len;
156	if (depth != 0 && len > depth)
157		len = depth;
158
159	rcsnum_setsize(ndst, len);
160	memcpy(ndst->rn_id, nsrc->rn_id, len * sizeof(*(nsrc->rn_id)));
161}
162
163/*
164 * rcsnum_cmp()
165 *
166 * Compare the two numbers <n1> and <n2>. Returns -1 if <n1> is larger than
167 * <n2>, 0 if they are both the same, and 1 if <n2> is larger than <n1>.
168 * The <depth> argument specifies how many numbers deep should be checked for
169 * the result.  A value of 0 means that the depth will be the maximum of the
170 * two numbers, so that a longer number is considered greater than a shorter
171 * number if they are equal up to the minimum length.
172 */
173int
174rcsnum_cmp(RCSNUM *n1, RCSNUM *n2, u_int depth)
175{
176	int res;
177	u_int i;
178	size_t slen;
179
180	if (!rcsnum_differ(n1, n2))
181		return (0);
182
183	slen = MINIMUM(n1->rn_len, n2->rn_len);
184	if (depth != 0 && slen > depth)
185		slen = depth;
186
187	for (i = 0; i < slen; i++) {
188		res = n1->rn_id[i] - n2->rn_id[i];
189		if (res < 0)
190			return (1);
191		else if (res > 0)
192			return (-1);
193	}
194
195	/* If an explicit depth was specified, and we've
196	 * already checked up to depth, consider the
197	 * revision numbers equal. */
198	if (depth != 0 && slen == depth)
199		return (0);
200	else if (n1->rn_len > n2->rn_len)
201		return (-1);
202	else if (n2->rn_len > n1->rn_len)
203		return (1);
204
205	return (0);
206}
207
208/*
209 * rcsnum_aton()
210 *
211 * Translate the string <str> containing a sequence of digits and periods into
212 * its binary representation, which is stored in <nump>.  The address of the
213 * first byte not part of the number is stored in <ep> on return, if it is not
214 * NULL.
215 * Returns 0 on success, or -1 on failure.
216 */
217int
218rcsnum_aton(const char *str, const char **ep, RCSNUM *nump)
219{
220	u_int32_t val;
221	const char *sp;
222	char *s;
223
224	nump->rn_len = 0;
225	nump->rn_id[0] = 0;
226
227	for (sp = str;; sp++) {
228		if (!isdigit((unsigned char)*sp) && (*sp != '.'))
229			break;
230
231		if (*sp == '.') {
232			if (nump->rn_len >= RCSNUM_MAXLEN - 1)
233				goto rcsnum_aton_failed;
234
235			nump->rn_len++;
236			nump->rn_id[nump->rn_len] = 0;
237			continue;
238		}
239
240		val = (nump->rn_id[nump->rn_len] * 10) + (*sp - '0');
241		if (val > RCSNUM_MAXNUM)
242			fatal("RCSNUM overflow!");
243
244		nump->rn_id[nump->rn_len] = val;
245	}
246
247	if (ep != NULL)
248		*ep = sp;
249
250	/*
251	 * Handle "magic" RCS branch numbers.
252	 *
253	 * What are they?
254	 *
255	 * Magic branch numbers have an extra .0. at the second farmost
256	 * rightside of the branch number, so instead of having an odd
257	 * number of dot-separated decimals, it will have an even number.
258	 *
259	 * Now, according to all the documentation I've found on the net
260	 * about this, cvs does this for "efficiency reasons", I'd like
261	 * to hear one.
262	 *
263	 * We just make sure we remove the .0. from in the branch number.
264	 *
265	 * XXX - for compatibility reasons with GNU cvs we _need_
266	 * to skip this part for the 'log' command, apparently it does
267	 * show the magic branches for an unknown and probably
268	 * completely insane and not understandable reason in that output.
269	 *
270	 */
271	if (nump->rn_len > 2 && nump->rn_id[nump->rn_len - 1] == 0) {
272		/*
273		 * Look for ".0.x" at the end of the branch number.
274		 */
275		if ((s = strrchr(str, '.')) != NULL) {
276			s--;
277			while (*s != '.')
278				s--;
279
280			/*
281			 * If we have a "magic" branch, adjust it
282			 * so the .0. is removed.
283			 */
284			if (!strncmp(s, RCS_MAGIC_BRANCH,
285			    sizeof(RCS_MAGIC_BRANCH) - 1)) {
286				nump->rn_id[nump->rn_len - 1] =
287				    nump->rn_id[nump->rn_len];
288				nump->rn_len--;
289			}
290		}
291	}
292
293	/* We can't have a single-digit rcs number. */
294	if (nump->rn_len == 0) {
295		nump->rn_len++;
296		nump->rn_id[nump->rn_len] = 0;
297	}
298
299	nump->rn_len++;
300	return (nump->rn_len);
301
302rcsnum_aton_failed:
303	nump->rn_len = 0;
304	return (-1);
305}
306
307/*
308 * rcsnum_inc()
309 *
310 * Increment the revision number specified in <num>.
311 * Returns a pointer to the <num> on success, or NULL on failure.
312 */
313RCSNUM *
314rcsnum_inc(RCSNUM *num)
315{
316	if (num->rn_id[num->rn_len - 1] == RCSNUM_MAXNUM)
317		return (NULL);
318	num->rn_id[num->rn_len - 1]++;
319	return (num);
320}
321
322/*
323 * rcsnum_dec()
324 *
325 * Decreases the revision number specified in <num>, if doing so will not
326 * result in an ending value below 1. E.g. 4.2 will go to 4.1 but 4.1 will
327 * be returned as 4.1.
328 */
329RCSNUM *
330rcsnum_dec(RCSNUM *num)
331{
332	/* XXX - Is it an error for the number to be 0? */
333	if (num->rn_id[num->rn_len - 1] <= 1)
334		return (num);
335	num->rn_id[num->rn_len - 1]--;
336	return (num);
337}
338
339/*
340 * rcsnum_revtobr()
341 *
342 * Retrieve the branch number associated with the revision number <num>.
343 * If <num> is a branch revision, the returned value will be the same
344 * number as the argument.
345 */
346RCSNUM *
347rcsnum_revtobr(const RCSNUM *num)
348{
349	RCSNUM *brnum;
350
351	if (num->rn_len < 2)
352		return (NULL);
353
354	brnum = rcsnum_alloc();
355	rcsnum_cpy(num, brnum, 0);
356
357	if (!RCSNUM_ISBRANCH(brnum))
358		brnum->rn_len--;
359
360	return (brnum);
361}
362
363/*
364 * rcsnum_brtorev()
365 *
366 * Retrieve the initial revision number associated with the branch number <num>.
367 * If <num> is a revision number, an error will be returned.
368 */
369RCSNUM *
370rcsnum_brtorev(const RCSNUM *brnum)
371{
372	RCSNUM *num;
373
374	if (!RCSNUM_ISBRANCH(brnum)) {
375		return (NULL);
376	}
377
378	num = rcsnum_alloc();
379	rcsnum_setsize(num, brnum->rn_len + 1);
380	rcsnum_cpy(brnum, num, brnum->rn_len);
381	num->rn_id[num->rn_len++] = 1;
382
383	return (num);
384}
385
386RCSNUM *
387rcsnum_new_branch(RCSNUM *rev)
388{
389	RCSNUM *branch;
390
391	if (rev->rn_len > RCSNUM_MAXLEN - 1)
392		return NULL;
393
394	branch = rcsnum_alloc();
395	rcsnum_cpy(rev, branch, 0);
396	rcsnum_setsize(branch, rev->rn_len + 1);
397	branch->rn_id[branch->rn_len - 1] = 2;
398
399	return branch;
400}
401
402RCSNUM *
403rcsnum_branch_root(RCSNUM *brev)
404{
405	RCSNUM *root;
406
407	if (!RCSNUM_ISBRANCHREV(brev))
408		fatal("rcsnum_branch_root: no revision on branch specified");
409
410	root = rcsnum_alloc();
411	rcsnum_cpy(brev, root, 0);
412	root->rn_len -= 2;
413	return (root);
414}
415
416static void
417rcsnum_setsize(RCSNUM *num, u_int len)
418{
419	num->rn_len = len;
420}
421
422int
423rcsnum_differ(RCSNUM *r1, RCSNUM *r2)
424{
425	int i, len;
426
427	if (r1->rn_len != r2->rn_len)
428		return (1);
429
430	len = MINIMUM(r1->rn_len, r2->rn_len);
431	for (i = 0; i < len; i++) {
432		if (r1->rn_id[i] != r2->rn_id[i])
433			return (1);
434	}
435
436	return (0);
437}
438