rcsnum.c revision 1.56 
1/*	$OpenBSD: rcsnum.c,v 1.56 2015/01/16 06:40:07 deraadt 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 <string.h>
29
30#include "cvs.h"
31
32#define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
33
34static void	 rcsnum_setsize(RCSNUM *, u_int);
35static char	*rcsnum_itoa(u_int16_t, char *, size_t);
36
37/*
38 * rcsnum_alloc()
39 *
40 * Allocate an RCS number structure and return a pointer to it.
41 */
42RCSNUM *
43rcsnum_alloc(void)
44{
45	RCSNUM *rnp;
46
47	rnp = xcalloc(1, sizeof(*rnp));
48	rnp->rn_len = 0;
49
50	return (rnp);
51}
52
53/*
54 * rcsnum_addmagic()
55 *
56 * Adds a magic branch number to an RCS number.
57 * Returns 0 on success, or -1 on failure.
58 */
59int
60rcsnum_addmagic(RCSNUM *rn)
61{
62	if (!rn->rn_len || rn->rn_len > RCSNUM_MAXLEN - 1)
63		return -1;
64	rcsnum_setsize(rn, rn->rn_len + 1);
65	rn->rn_id[rn->rn_len - 1] = rn->rn_id[rn->rn_len - 2];
66	rn->rn_id[rn->rn_len - 2] = 0;
67
68	return 0;
69}
70
71/*
72 * rcsnum_parse()
73 *
74 * Parse a string specifying an RCS number and return the corresponding RCSNUM.
75 */
76RCSNUM *
77rcsnum_parse(const char *str)
78{
79	char *ep;
80	RCSNUM *num;
81
82	num = rcsnum_alloc();
83	if (rcsnum_aton(str, &ep, num) < 0 || *ep != '\0') {
84		rcsnum_free(num);
85		num = NULL;
86	}
87
88	return (num);
89}
90
91/*
92 * rcsnum_free()
93 *
94 * Free an RCSNUM structure previously allocated with rcsnum_alloc().
95 */
96void
97rcsnum_free(RCSNUM *rn)
98{
99	xfree(rn);
100}
101
102/*
103 * rcsnum_tostr()
104 *
105 * Format the RCS number <nump> into a human-readable dot-separated
106 * representation and store the resulting string in <buf>, which is of size
107 * <blen>.
108 * Returns a pointer to the start of <buf>.  On failure <buf> is set to
109 * an empty string.
110 */
111char *
112rcsnum_tostr(const RCSNUM *nump, char *buf, size_t blen)
113{
114	u_int i;
115	char tmp[8];
116
117	if (nump == NULL || nump->rn_len == 0) {
118		buf[0] = '\0';
119		return (buf);
120	}
121
122	if (strlcpy(buf, rcsnum_itoa(nump->rn_id[0], buf, blen), blen) >= blen)
123		fatal("rcsnum_tostr: truncation");
124	for (i = 1; i < nump->rn_len; i++) {
125		const char *str;
126
127		str = rcsnum_itoa(nump->rn_id[i], tmp, sizeof(tmp));
128		if (strlcat(buf, ".", blen) >= blen ||
129		    strlcat(buf, str, blen) >= blen)
130			fatal("rcsnum_tostr: truncation");
131	}
132	return (buf);
133}
134
135static char *
136rcsnum_itoa(u_int16_t num, char *buf, size_t len)
137{
138	u_int16_t i;
139	char *p;
140
141	if (num == 0)
142		return "0";
143
144	p = buf + len - 1;
145	i = num;
146	bzero(buf, len);
147	while (i) {
148		*--p = '0' + (i % 10);
149		i  /= 10;
150	}
151	return (p);
152}
153
154/*
155 * rcsnum_cpy()
156 *
157 * Copy the number stored in <nsrc> in the destination <ndst> up to <depth>
158 * numbers deep.  If <depth> is 0, there is no depth limit.
159 */
160void
161rcsnum_cpy(const RCSNUM *nsrc, RCSNUM *ndst, u_int depth)
162{
163	u_int len;
164
165	len = nsrc->rn_len;
166	if (depth != 0 && len > depth)
167		len = depth;
168
169	rcsnum_setsize(ndst, len);
170	memcpy(ndst->rn_id, nsrc->rn_id, len * sizeof(*(nsrc->rn_id)));
171}
172
173/*
174 * rcsnum_cmp()
175 *
176 * Compare the two numbers <n1> and <n2>. Returns -1 if <n1> is larger than
177 * <n2>, 0 if they are both the same, and 1 if <n2> is larger than <n1>.
178 * The <depth> argument specifies how many numbers deep should be checked for
179 * the result.  A value of 0 means that the depth will be the maximum of the
180 * two numbers, so that a longer number is considered greater than a shorter
181 * number if they are equal up to the minimum length.
182 */
183int
184rcsnum_cmp(RCSNUM *n1, RCSNUM *n2, u_int depth)
185{
186	int res;
187	u_int i;
188	size_t slen;
189
190	if (!rcsnum_differ(n1, n2))
191		return (0);
192
193	slen = MINIMUM(n1->rn_len, n2->rn_len);
194	if (depth != 0 && slen > depth)
195		slen = depth;
196
197	for (i = 0; i < slen; i++) {
198		res = n1->rn_id[i] - n2->rn_id[i];
199		if (res < 0)
200			return (1);
201		else if (res > 0)
202			return (-1);
203	}
204
205	/* If an explicit depth was specified, and we've
206	 * already checked up to depth, consider the
207	 * revision numbers equal. */
208	if (depth != 0 && slen == depth)
209		return (0);
210	else if (n1->rn_len > n2->rn_len)
211		return (-1);
212	else if (n2->rn_len > n1->rn_len)
213		return (1);
214
215	return (0);
216}
217
218/*
219 * rcsnum_aton()
220 *
221 * Translate the string <str> containing a sequence of digits and periods into
222 * its binary representation, which is stored in <nump>.  The address of the
223 * first byte not part of the number is stored in <ep> on return, if it is not
224 * NULL.
225 * Returns 0 on success, or -1 on failure.
226 */
227int
228rcsnum_aton(const char *str, char **ep, RCSNUM *nump)
229{
230	u_int32_t val;
231	const char *sp;
232	char *s;
233
234	nump->rn_len = 0;
235	nump->rn_id[0] = 0;
236
237	for (sp = str;; sp++) {
238		if (!isdigit((unsigned char)*sp) && (*sp != '.'))
239			break;
240
241		if (*sp == '.') {
242			if (nump->rn_len >= RCSNUM_MAXLEN - 1)
243				goto rcsnum_aton_failed;
244
245			nump->rn_len++;
246			nump->rn_id[nump->rn_len] = 0;
247			continue;
248		}
249
250		val = (nump->rn_id[nump->rn_len] * 10) + (*sp - '0');
251		if (val > RCSNUM_MAXNUM)
252			fatal("RCSNUM overflow!");
253
254		nump->rn_id[nump->rn_len] = val;
255	}
256
257	if (ep != NULL)
258		*(const char **)ep = sp;
259
260	/*
261	 * Handle "magic" RCS branch numbers.
262	 *
263	 * What are they?
264	 *
265	 * Magic branch numbers have an extra .0. at the second farmost
266	 * rightside of the branch number, so instead of having an odd
267	 * number of dot-separated decimals, it will have an even number.
268	 *
269	 * Now, according to all the documentation I've found on the net
270	 * about this, cvs does this for "efficiency reasons", I'd like
271	 * to hear one.
272	 *
273	 * We just make sure we remove the .0. from in the branch number.
274	 *
275	 * XXX - for compatibility reasons with GNU cvs we _need_
276	 * to skip this part for the 'log' command, apparently it does
277	 * show the magic branches for an unknown and probably
278	 * completely insane and not understandable reason in that output.
279	 *
280	 */
281	if (nump->rn_len > 2 && nump->rn_id[nump->rn_len - 1] == 0) {
282		/*
283		 * Look for ".0.x" at the end of the branch number.
284		 */
285		if ((s = strrchr(str, '.')) != NULL) {
286			s--;
287			while (*s != '.')
288				s--;
289
290			/*
291			 * If we have a "magic" branch, adjust it
292			 * so the .0. is removed.
293			 */
294			if (!strncmp(s, RCS_MAGIC_BRANCH,
295			    sizeof(RCS_MAGIC_BRANCH) - 1)) {
296				nump->rn_id[nump->rn_len - 1] =
297				    nump->rn_id[nump->rn_len];
298				nump->rn_len--;
299			}
300		}
301	}
302
303	/* We can't have a single-digit rcs number. */
304	if (nump->rn_len == 0) {
305		nump->rn_len++;
306		nump->rn_id[nump->rn_len] = 0;
307	}
308
309	nump->rn_len++;
310	return (nump->rn_len);
311
312rcsnum_aton_failed:
313	nump->rn_len = 0;
314	return (-1);
315}
316
317/*
318 * rcsnum_inc()
319 *
320 * Increment the revision number specified in <num>.
321 * Returns a pointer to the <num> on success, or NULL on failure.
322 */
323RCSNUM *
324rcsnum_inc(RCSNUM *num)
325{
326	if (num->rn_id[num->rn_len - 1] == RCSNUM_MAXNUM)
327		return (NULL);
328	num->rn_id[num->rn_len - 1]++;
329	return (num);
330}
331
332/*
333 * rcsnum_dec()
334 *
335 * Decreases the revision number specified in <num>, if doing so will not
336 * result in an ending value below 1. E.g. 4.2 will go to 4.1 but 4.1 will
337 * be returned as 4.1.
338 */
339RCSNUM *
340rcsnum_dec(RCSNUM *num)
341{
342	/* XXX - Is it an error for the number to be 0? */
343	if (num->rn_id[num->rn_len - 1] <= 1)
344		return (num);
345	num->rn_id[num->rn_len - 1]--;
346	return (num);
347}
348
349/*
350 * rcsnum_revtobr()
351 *
352 * Retrieve the branch number associated with the revision number <num>.
353 * If <num> is a branch revision, the returned value will be the same
354 * number as the argument.
355 */
356RCSNUM *
357rcsnum_revtobr(const RCSNUM *num)
358{
359	RCSNUM *brnum;
360
361	if (num->rn_len < 2)
362		return (NULL);
363
364	brnum = rcsnum_alloc();
365	rcsnum_cpy(num, brnum, 0);
366
367	if (!RCSNUM_ISBRANCH(brnum))
368		brnum->rn_len--;
369
370	return (brnum);
371}
372
373/*
374 * rcsnum_brtorev()
375 *
376 * Retrieve the initial revision number associated with the branch number <num>.
377 * If <num> is a revision number, an error will be returned.
378 */
379RCSNUM *
380rcsnum_brtorev(const RCSNUM *brnum)
381{
382	RCSNUM *num;
383
384	if (!RCSNUM_ISBRANCH(brnum)) {
385		return (NULL);
386	}
387
388	num = rcsnum_alloc();
389	rcsnum_setsize(num, brnum->rn_len + 1);
390	rcsnum_cpy(brnum, num, brnum->rn_len);
391	num->rn_id[num->rn_len++] = 1;
392
393	return (num);
394}
395
396RCSNUM *
397rcsnum_new_branch(RCSNUM *rev)
398{
399	RCSNUM *branch;
400
401	if (rev->rn_len > RCSNUM_MAXLEN - 1)
402		return NULL;
403
404	branch = rcsnum_alloc();
405	rcsnum_cpy(rev, branch, 0);
406	rcsnum_setsize(branch, rev->rn_len + 1);
407	branch->rn_id[branch->rn_len - 1] = 2;
408
409	return branch;
410}
411
412RCSNUM *
413rcsnum_branch_root(RCSNUM *brev)
414{
415	RCSNUM *root;
416
417	if (!RCSNUM_ISBRANCHREV(brev))
418		fatal("rcsnum_branch_root: no revision on branch specified");
419
420	root = rcsnum_alloc();
421	rcsnum_cpy(brev, root, 0);
422	root->rn_len -= 2;
423	return (root);
424}
425
426static void
427rcsnum_setsize(RCSNUM *num, u_int len)
428{
429	num->rn_len = len;
430}
431
432int
433rcsnum_differ(RCSNUM *r1, RCSNUM *r2)
434{
435	int i, len;
436
437	if (r1->rn_len != r2->rn_len)
438		return (1);
439
440	len = MINIMUM(r1->rn_len, r2->rn_len);
441	for (i = 0; i < len; i++) {
442		if (r1->rn_id[i] != r2->rn_id[i])
443			return (1);
444	}
445
446	return (0);
447}
448