rcsnum.c revision 1.57 
1/*	$OpenBSD: rcsnum.c,v 1.57 2015/11/05 09:48:21 nicm 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	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	}
88
89	return (num);
90}
91
92/*
93 * rcsnum_free()
94 *
95 * Free an RCSNUM structure previously allocated with rcsnum_alloc().
96 */
97void
98rcsnum_free(RCSNUM *rn)
99{
100	free(rn);
101}
102
103/*
104 * rcsnum_tostr()
105 *
106 * Format the RCS number <nump> into a human-readable dot-separated
107 * representation and store the resulting string in <buf>, which is of size
108 * <blen>.
109 * Returns a pointer to the start of <buf>.  On failure <buf> is set to
110 * an empty string.
111 */
112char *
113rcsnum_tostr(const RCSNUM *nump, char *buf, size_t blen)
114{
115	u_int i;
116	char tmp[8];
117
118	if (nump == NULL || nump->rn_len == 0) {
119		buf[0] = '\0';
120		return (buf);
121	}
122
123	if (strlcpy(buf, rcsnum_itoa(nump->rn_id[0], buf, blen), blen) >= blen)
124		fatal("rcsnum_tostr: truncation");
125	for (i = 1; i < nump->rn_len; i++) {
126		const char *str;
127
128		str = rcsnum_itoa(nump->rn_id[i], tmp, sizeof(tmp));
129		if (strlcat(buf, ".", blen) >= blen ||
130		    strlcat(buf, str, blen) >= blen)
131			fatal("rcsnum_tostr: truncation");
132	}
133	return (buf);
134}
135
136static char *
137rcsnum_itoa(u_int16_t num, char *buf, size_t len)
138{
139	u_int16_t i;
140	char *p;
141
142	if (num == 0)
143		return "0";
144
145	p = buf + len - 1;
146	i = num;
147	bzero(buf, len);
148	while (i) {
149		*--p = '0' + (i % 10);
150		i  /= 10;
151	}
152	return (p);
153}
154
155/*
156 * rcsnum_cpy()
157 *
158 * Copy the number stored in <nsrc> in the destination <ndst> up to <depth>
159 * numbers deep.  If <depth> is 0, there is no depth limit.
160 */
161void
162rcsnum_cpy(const RCSNUM *nsrc, RCSNUM *ndst, u_int depth)
163{
164	u_int len;
165
166	len = nsrc->rn_len;
167	if (depth != 0 && len > depth)
168		len = depth;
169
170	rcsnum_setsize(ndst, len);
171	memcpy(ndst->rn_id, nsrc->rn_id, len * sizeof(*(nsrc->rn_id)));
172}
173
174/*
175 * rcsnum_cmp()
176 *
177 * Compare the two numbers <n1> and <n2>. Returns -1 if <n1> is larger than
178 * <n2>, 0 if they are both the same, and 1 if <n2> is larger than <n1>.
179 * The <depth> argument specifies how many numbers deep should be checked for
180 * the result.  A value of 0 means that the depth will be the maximum of the
181 * two numbers, so that a longer number is considered greater than a shorter
182 * number if they are equal up to the minimum length.
183 */
184int
185rcsnum_cmp(RCSNUM *n1, RCSNUM *n2, u_int depth)
186{
187	int res;
188	u_int i;
189	size_t slen;
190
191	if (!rcsnum_differ(n1, n2))
192		return (0);
193
194	slen = MINIMUM(n1->rn_len, n2->rn_len);
195	if (depth != 0 && slen > depth)
196		slen = depth;
197
198	for (i = 0; i < slen; i++) {
199		res = n1->rn_id[i] - n2->rn_id[i];
200		if (res < 0)
201			return (1);
202		else if (res > 0)
203			return (-1);
204	}
205
206	/* If an explicit depth was specified, and we've
207	 * already checked up to depth, consider the
208	 * revision numbers equal. */
209	if (depth != 0 && slen == depth)
210		return (0);
211	else if (n1->rn_len > n2->rn_len)
212		return (-1);
213	else if (n2->rn_len > n1->rn_len)
214		return (1);
215
216	return (0);
217}
218
219/*
220 * rcsnum_aton()
221 *
222 * Translate the string <str> containing a sequence of digits and periods into
223 * its binary representation, which is stored in <nump>.  The address of the
224 * first byte not part of the number is stored in <ep> on return, if it is not
225 * NULL.
226 * Returns 0 on success, or -1 on failure.
227 */
228int
229rcsnum_aton(const char *str, char **ep, RCSNUM *nump)
230{
231	u_int32_t val;
232	const char *sp;
233	char *s;
234
235	nump->rn_len = 0;
236	nump->rn_id[0] = 0;
237
238	for (sp = str;; sp++) {
239		if (!isdigit((unsigned char)*sp) && (*sp != '.'))
240			break;
241
242		if (*sp == '.') {
243			if (nump->rn_len >= RCSNUM_MAXLEN - 1)
244				goto rcsnum_aton_failed;
245
246			nump->rn_len++;
247			nump->rn_id[nump->rn_len] = 0;
248			continue;
249		}
250
251		val = (nump->rn_id[nump->rn_len] * 10) + (*sp - '0');
252		if (val > RCSNUM_MAXNUM)
253			fatal("RCSNUM overflow!");
254
255		nump->rn_id[nump->rn_len] = val;
256	}
257
258	if (ep != NULL)
259		*(const char **)ep = sp;
260
261	/*
262	 * Handle "magic" RCS branch numbers.
263	 *
264	 * What are they?
265	 *
266	 * Magic branch numbers have an extra .0. at the second farmost
267	 * rightside of the branch number, so instead of having an odd
268	 * number of dot-separated decimals, it will have an even number.
269	 *
270	 * Now, according to all the documentation I've found on the net
271	 * about this, cvs does this for "efficiency reasons", I'd like
272	 * to hear one.
273	 *
274	 * We just make sure we remove the .0. from in the branch number.
275	 *
276	 * XXX - for compatibility reasons with GNU cvs we _need_
277	 * to skip this part for the 'log' command, apparently it does
278	 * show the magic branches for an unknown and probably
279	 * completely insane and not understandable reason in that output.
280	 *
281	 */
282	if (nump->rn_len > 2 && nump->rn_id[nump->rn_len - 1] == 0) {
283		/*
284		 * Look for ".0.x" at the end of the branch number.
285		 */
286		if ((s = strrchr(str, '.')) != NULL) {
287			s--;
288			while (*s != '.')
289				s--;
290
291			/*
292			 * If we have a "magic" branch, adjust it
293			 * so the .0. is removed.
294			 */
295			if (!strncmp(s, RCS_MAGIC_BRANCH,
296			    sizeof(RCS_MAGIC_BRANCH) - 1)) {
297				nump->rn_id[nump->rn_len - 1] =
298				    nump->rn_id[nump->rn_len];
299				nump->rn_len--;
300			}
301		}
302	}
303
304	/* We can't have a single-digit rcs number. */
305	if (nump->rn_len == 0) {
306		nump->rn_len++;
307		nump->rn_id[nump->rn_len] = 0;
308	}
309
310	nump->rn_len++;
311	return (nump->rn_len);
312
313rcsnum_aton_failed:
314	nump->rn_len = 0;
315	return (-1);
316}
317
318/*
319 * rcsnum_inc()
320 *
321 * Increment the revision number specified in <num>.
322 * Returns a pointer to the <num> on success, or NULL on failure.
323 */
324RCSNUM *
325rcsnum_inc(RCSNUM *num)
326{
327	if (num->rn_id[num->rn_len - 1] == RCSNUM_MAXNUM)
328		return (NULL);
329	num->rn_id[num->rn_len - 1]++;
330	return (num);
331}
332
333/*
334 * rcsnum_dec()
335 *
336 * Decreases the revision number specified in <num>, if doing so will not
337 * result in an ending value below 1. E.g. 4.2 will go to 4.1 but 4.1 will
338 * be returned as 4.1.
339 */
340RCSNUM *
341rcsnum_dec(RCSNUM *num)
342{
343	/* XXX - Is it an error for the number to be 0? */
344	if (num->rn_id[num->rn_len - 1] <= 1)
345		return (num);
346	num->rn_id[num->rn_len - 1]--;
347	return (num);
348}
349
350/*
351 * rcsnum_revtobr()
352 *
353 * Retrieve the branch number associated with the revision number <num>.
354 * If <num> is a branch revision, the returned value will be the same
355 * number as the argument.
356 */
357RCSNUM *
358rcsnum_revtobr(const RCSNUM *num)
359{
360	RCSNUM *brnum;
361
362	if (num->rn_len < 2)
363		return (NULL);
364
365	brnum = rcsnum_alloc();
366	rcsnum_cpy(num, brnum, 0);
367
368	if (!RCSNUM_ISBRANCH(brnum))
369		brnum->rn_len--;
370
371	return (brnum);
372}
373
374/*
375 * rcsnum_brtorev()
376 *
377 * Retrieve the initial revision number associated with the branch number <num>.
378 * If <num> is a revision number, an error will be returned.
379 */
380RCSNUM *
381rcsnum_brtorev(const RCSNUM *brnum)
382{
383	RCSNUM *num;
384
385	if (!RCSNUM_ISBRANCH(brnum)) {
386		return (NULL);
387	}
388
389	num = rcsnum_alloc();
390	rcsnum_setsize(num, brnum->rn_len + 1);
391	rcsnum_cpy(brnum, num, brnum->rn_len);
392	num->rn_id[num->rn_len++] = 1;
393
394	return (num);
395}
396
397RCSNUM *
398rcsnum_new_branch(RCSNUM *rev)
399{
400	RCSNUM *branch;
401
402	if (rev->rn_len > RCSNUM_MAXLEN - 1)
403		return NULL;
404
405	branch = rcsnum_alloc();
406	rcsnum_cpy(rev, branch, 0);
407	rcsnum_setsize(branch, rev->rn_len + 1);
408	branch->rn_id[branch->rn_len - 1] = 2;
409
410	return branch;
411}
412
413RCSNUM *
414rcsnum_branch_root(RCSNUM *brev)
415{
416	RCSNUM *root;
417
418	if (!RCSNUM_ISBRANCHREV(brev))
419		fatal("rcsnum_branch_root: no revision on branch specified");
420
421	root = rcsnum_alloc();
422	rcsnum_cpy(brev, root, 0);
423	root->rn_len -= 2;
424	return (root);
425}
426
427static void
428rcsnum_setsize(RCSNUM *num, u_int len)
429{
430	num->rn_len = len;
431}
432
433int
434rcsnum_differ(RCSNUM *r1, RCSNUM *r2)
435{
436	int i, len;
437
438	if (r1->rn_len != r2->rn_len)
439		return (1);
440
441	len = MINIMUM(r1->rn_len, r2->rn_len);
442	for (i = 0; i < len; i++) {
443		if (r1->rn_id[i] != r2->rn_id[i])
444			return (1);
445	}
446
447	return (0);
448}
449