rcsnum.c revision 1.50 
1/*	$OpenBSD: rcsnum.c,v 1.50 2008/01/31 22:19:36 tobias 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
32static void	 rcsnum_setsize(RCSNUM *, u_int);
33static char	*rcsnum_itoa(u_int16_t, char *, size_t);
34
35int rcsnum_flags;
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 = xmalloc(sizeof(*rnp));
48	rnp->rn_len = 0;
49	rnp->rn_id = NULL;
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	char *ep;
81	RCSNUM *num;
82
83	num = rcsnum_alloc();
84	if (rcsnum_aton(str, &ep, num) < 0 || *ep != '\0') {
85		rcsnum_free(num);
86		num = NULL;
87		if (*ep != '\0')
88			rcs_errno = RCS_ERR_BADNUM;
89	}
90
91	return (num);
92}
93
94/*
95 * rcsnum_free()
96 *
97 * Free an RCSNUM structure previously allocated with rcsnum_alloc().
98 */
99void
100rcsnum_free(RCSNUM *rn)
101{
102	if (rn->rn_id != NULL)
103		xfree(rn->rn_id);
104	xfree(rn);
105}
106
107/*
108 * rcsnum_tostr()
109 *
110 * Format the RCS number <nump> into a human-readable dot-separated
111 * representation and store the resulting string in <buf>, which is of size
112 * <blen>.
113 * Returns a pointer to the start of <buf>.  On failure <buf> is set to
114 * an empty string.
115 */
116char *
117rcsnum_tostr(const RCSNUM *nump, char *buf, size_t blen)
118{
119	u_int i;
120	char tmp[8];
121
122	if (nump == NULL || nump->rn_len == 0) {
123		buf[0] = '\0';
124		return (buf);
125	}
126
127	if (strlcpy(buf, rcsnum_itoa(nump->rn_id[0], buf, blen), blen) >= blen)
128		fatal("rcsnum_tostr: truncation");
129	for (i = 1; i < nump->rn_len; i++) {
130		const char *str;
131
132		str = rcsnum_itoa(nump->rn_id[i], tmp, sizeof(tmp));
133		if (strlcat(buf, ".", blen) >= blen ||
134		    strlcat(buf, str, blen) >= blen)
135			fatal("rcsnum_tostr: truncation");
136	}
137
138	return (buf);
139}
140
141static char *
142rcsnum_itoa(u_int16_t num, char *buf, size_t len)
143{
144	u_int16_t i;
145	char *p;
146
147	if (num == 0)
148		return "0";
149
150	p = buf + len - 1;
151	i = num;
152	bzero(buf, len);
153	while (i) {
154		*--p = '0' + (i % 10);
155		i  /= 10;
156	}
157	return (p);
158}
159
160/*
161 * rcsnum_cpy()
162 *
163 * Copy the number stored in <nsrc> in the destination <ndst> up to <depth>
164 * numbers deep.  If <depth> is 0, there is no depth limit.
165 */
166void
167rcsnum_cpy(const RCSNUM *nsrc, RCSNUM *ndst, u_int depth)
168{
169	u_int len;
170
171	len = nsrc->rn_len;
172	if (depth != 0 && len > depth)
173		len = depth;
174
175	rcsnum_setsize(ndst, len);
176	/* Overflow checked in rcsnum_setsize(). */
177	(void)memcpy(ndst->rn_id, nsrc->rn_id,
178	    len * sizeof(*(nsrc->rn_id)));
179}
180
181/*
182 * rcsnum_cmp()
183 *
184 * Compare the two numbers <n1> and <n2>. Returns -1 if <n1> is larger than
185 * <n2>, 0 if they are both the same, and 1 if <n2> is larger than <n1>.
186 * The <depth> argument specifies how many numbers deep should be checked for
187 * the result.  A value of 0 means that the depth will be the minimum of the
188 * two numbers.
189 */
190int
191rcsnum_cmp(RCSNUM *n1, RCSNUM *n2, u_int depth)
192{
193	int res;
194	u_int i;
195	size_t slen;
196
197	if (!rcsnum_differ(n1, n2))
198		return (0);
199
200	slen = MIN(n1->rn_len, n2->rn_len);
201	if (depth != 0 && slen > depth)
202		slen = depth;
203
204	for (i = 0; i < slen; i++) {
205		res = n1->rn_id[i] - n2->rn_id[i];
206		if (res < 0)
207			return (1);
208		else if (res > 0)
209			return (-1);
210	}
211
212	if (n1->rn_len > n2->rn_len)
213		return (-1);
214	else if (n2->rn_len > n1->rn_len)
215		return (1);
216
217	return (0);
218}
219
220/*
221 * rcsnum_aton()
222 *
223 * Translate the string <str> containing a sequence of digits and periods into
224 * its binary representation, which is stored in <nump>.  The address of the
225 * first byte not part of the number is stored in <ep> on return, if it is not
226 * NULL.
227 * Returns 0 on success, or -1 on failure.
228 */
229int
230rcsnum_aton(const char *str, char **ep, RCSNUM *nump)
231{
232	u_int32_t val;
233	const char *sp;
234	char *s;
235
236	if (nump->rn_id == NULL)
237		nump->rn_id = xmalloc(sizeof(*(nump->rn_id)));
238
239	nump->rn_len = 0;
240	nump->rn_id[0] = 0;
241
242	for (sp = str;; sp++) {
243		if (!isdigit(*sp) && (*sp != '.'))
244			break;
245
246		if (*sp == '.') {
247			if (nump->rn_len >= RCSNUM_MAXLEN - 1) {
248				rcs_errno = RCS_ERR_BADNUM;
249				goto rcsnum_aton_failed;
250			}
251
252			nump->rn_len++;
253			nump->rn_id = xrealloc(nump->rn_id,
254			    nump->rn_len + 1, sizeof(*(nump->rn_id)));
255			nump->rn_id[nump->rn_len] = 0;
256			continue;
257		}
258
259		val = (nump->rn_id[nump->rn_len] * 10) + (*sp - '0');
260		if (val > RCSNUM_MAXNUM)
261			fatal("RCSNUM overflow!");
262
263		nump->rn_id[nump->rn_len] = val;
264	}
265
266	if (ep != NULL)
267		*(const char **)ep = sp;
268
269	/*
270	 * Handle "magic" RCS branch numbers.
271	 *
272	 * What are they?
273	 *
274	 * Magic branch numbers have an extra .0. at the second farmost
275	 * rightside of the branch number, so instead of having an odd
276	 * number of dot-separated decimals, it will have an even number.
277	 *
278	 * Now, according to all the documentation I've found on the net
279	 * about this, cvs does this for "efficiency reasons", I'd like
280	 * to hear one.
281	 *
282	 * We just make sure we remove the .0. from in the branch number.
283	 *
284	 * XXX - for compatibility reasons with GNU cvs we _need_
285	 * to skip this part for the 'log' command, apparently it does
286	 * show the magic branches for an unknown and probably
287	 * completely insane and not understandable reason in that output.
288	 *
289	 */
290	if (nump->rn_len > 2 && nump->rn_id[nump->rn_len - 1] == 0
291	    && !(rcsnum_flags & RCSNUM_NO_MAGIC)) {
292		/*
293		 * Look for ".0.x" at the end of the branch number.
294		 */
295		if ((s = strrchr(str, '.')) != NULL) {
296			s--;
297			while (*s != '.')
298				s--;
299
300			/*
301			 * If we have a "magic" branch, adjust it
302			 * so the .0. is removed.
303			 */
304			if (!strncmp(s, RCS_MAGIC_BRANCH,
305			    sizeof(RCS_MAGIC_BRANCH) - 1)) {
306				nump->rn_id[nump->rn_len - 1] =
307				    nump->rn_id[nump->rn_len];
308				nump->rn_len--;
309			}
310		}
311	}
312
313	/* We can't have a single-digit rcs number. */
314	if (nump->rn_len == 0) {
315		nump->rn_len++;
316		nump->rn_id = xrealloc(nump->rn_id,
317		    nump->rn_len + 1, sizeof(*(nump->rn_id)));
318		nump->rn_id[nump->rn_len] = 0;
319	}
320
321	nump->rn_len++;
322	return (nump->rn_len);
323
324rcsnum_aton_failed:
325	nump->rn_len = 0;
326	xfree(nump->rn_id);
327	nump->rn_id = NULL;
328	return (-1);
329}
330
331/*
332 * rcsnum_inc()
333 *
334 * Increment the revision number specified in <num>.
335 * Returns a pointer to the <num> on success, or NULL on failure.
336 */
337RCSNUM *
338rcsnum_inc(RCSNUM *num)
339{
340	if (num->rn_id[num->rn_len - 1] == RCSNUM_MAXNUM)
341		return (NULL);
342	num->rn_id[num->rn_len - 1]++;
343	return (num);
344}
345
346/*
347 * rcsnum_dec()
348 *
349 * Decreases the revision number specified in <num>, if doing so will not
350 * result in an ending value below 1. E.g. 4.2 will go to 4.1 but 4.1 will
351 * be returned as 4.1.
352 */
353RCSNUM *
354rcsnum_dec(RCSNUM *num)
355{
356	/* XXX - Is it an error for the number to be 0? */
357	if (num->rn_id[num->rn_len - 1] <= 1)
358		return (num);
359	num->rn_id[num->rn_len - 1]--;
360	return (num);
361}
362
363/*
364 * rcsnum_revtobr()
365 *
366 * Retrieve the branch number associated with the revision number <num>.
367 * If <num> is a branch revision, the returned value will be the same
368 * number as the argument.
369 */
370RCSNUM *
371rcsnum_revtobr(const RCSNUM *num)
372{
373	RCSNUM *brnum;
374
375	if (num->rn_len < 2)
376		return (NULL);
377
378	brnum = rcsnum_alloc();
379	rcsnum_cpy(num, brnum, 0);
380
381	if (!RCSNUM_ISBRANCH(brnum))
382		brnum->rn_len--;
383
384	return (brnum);
385}
386
387/*
388 * rcsnum_brtorev()
389 *
390 * Retrieve the initial revision number associated with the branch number <num>.
391 * If <num> is a revision number, an error will be returned.
392 */
393RCSNUM *
394rcsnum_brtorev(const RCSNUM *brnum)
395{
396	RCSNUM *num;
397
398	if (!RCSNUM_ISBRANCH(brnum)) {
399		return (NULL);
400	}
401
402	num = rcsnum_alloc();
403	rcsnum_setsize(num, brnum->rn_len + 1);
404	rcsnum_cpy(brnum, num, brnum->rn_len);
405	num->rn_id[num->rn_len++] = 1;
406
407	return (num);
408}
409
410RCSNUM *
411rcsnum_new_branch(RCSNUM *rev)
412{
413	RCSNUM *branch;
414
415	if (rev->rn_len > RCSNUM_MAXLEN - 1)
416		return NULL;
417
418	branch = rcsnum_alloc();
419	rcsnum_cpy(rev, branch, 0);
420	rcsnum_setsize(branch, rev->rn_len + 1);
421	branch->rn_id[branch->rn_len - 1] = 2;
422
423	return branch;
424}
425
426RCSNUM *
427rcsnum_branch_root(RCSNUM *brev)
428{
429	RCSNUM *root;
430
431	if (!RCSNUM_ISBRANCHREV(brev))
432		fatal("rcsnum_branch_root: no revision on branch specified");
433
434	root = rcsnum_alloc();
435	rcsnum_cpy(brev, root, 0);
436	root->rn_len -= 2;
437	return (root);
438}
439
440static void
441rcsnum_setsize(RCSNUM *num, u_int len)
442{
443	num->rn_id = xrealloc(num->rn_id, len, sizeof(*(num->rn_id)));
444	num->rn_len = len;
445}
446
447int
448rcsnum_differ(RCSNUM *r1, RCSNUM *r2)
449{
450	int i, len;
451
452	if (r1->rn_len != r2->rn_len)
453		return (1);
454
455	len = MIN(r1->rn_len, r2->rn_len);
456	for (i = 0; i < len; i++) {
457		if (r1->rn_id[i] != r2->rn_id[i])
458			return (1);
459	}
460
461	return (0);
462}
463