rcsnum.c revision 1.46 
1/*	$OpenBSD: rcsnum.c,v 1.46 2007/09/04 17:57:41 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_parse()
56 *
57 * Parse a string specifying an RCS number and return the corresponding RCSNUM.
58 */
59RCSNUM *
60rcsnum_parse(const char *str)
61{
62	char *ep;
63	RCSNUM *num;
64
65	num = rcsnum_alloc();
66	if (rcsnum_aton(str, &ep, num) < 0 || *ep != '\0') {
67		rcsnum_free(num);
68		num = NULL;
69		if (*ep != '\0')
70			rcs_errno = RCS_ERR_BADNUM;
71	}
72
73	return (num);
74}
75
76/*
77 * rcsnum_free()
78 *
79 * Free an RCSNUM structure previously allocated with rcsnum_alloc().
80 */
81void
82rcsnum_free(RCSNUM *rn)
83{
84	if (rn->rn_id != NULL)
85		xfree(rn->rn_id);
86	xfree(rn);
87}
88
89/*
90 * rcsnum_tostr()
91 *
92 * Format the RCS number <nump> into a human-readable dot-separated
93 * representation and store the resulting string in <buf>, which is of size
94 * <blen>.
95 * Returns a pointer to the start of <buf>.  On failure <buf> is set to
96 * an empty string.
97 */
98char *
99rcsnum_tostr(const RCSNUM *nump, char *buf, size_t blen)
100{
101	u_int i;
102	char tmp[8];
103
104	if (nump == NULL || nump->rn_len == 0) {
105		buf[0] = '\0';
106		return (buf);
107	}
108
109	if (strlcpy(buf, rcsnum_itoa(nump->rn_id[0], buf, blen), blen) >= blen)
110		fatal("rcsnum_tostr: truncation");
111	for (i = 1; i < nump->rn_len; i++) {
112		const char *str;
113
114		str = rcsnum_itoa(nump->rn_id[i], tmp, sizeof(tmp));
115		if (strlcat(buf, ".", blen) >= blen ||
116		    strlcat(buf, str, blen) >= blen)
117			fatal("rcsnum_tostr: truncation");
118	}
119
120	return (buf);
121}
122
123static char *
124rcsnum_itoa(u_int16_t num, char *buf, size_t len)
125{
126	u_int16_t i;
127	char *p;
128
129	if (num == 0)
130		return "0";
131
132	p = buf + len - 1;
133	i = num;
134	bzero(buf, len);
135	while (i) {
136		*--p = '0' + (i % 10);
137		i  /= 10;
138	}
139	return (p);
140}
141
142/*
143 * rcsnum_cpy()
144 *
145 * Copy the number stored in <nsrc> in the destination <ndst> up to <depth>
146 * numbers deep.  If <depth> is 0, there is no depth limit.
147 */
148void
149rcsnum_cpy(const RCSNUM *nsrc, RCSNUM *ndst, u_int depth)
150{
151	u_int len;
152
153	len = nsrc->rn_len;
154	if (depth != 0 && len > depth)
155		len = depth;
156
157	rcsnum_setsize(ndst, len);
158	/* Overflow checked in rcsnum_setsize(). */
159	(void)memcpy(ndst->rn_id, nsrc->rn_id,
160	    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 minimum of the
170 * two numbers.
171 */
172int
173rcsnum_cmp(RCSNUM *n1, RCSNUM *n2, u_int depth)
174{
175	int res;
176	u_int i;
177	size_t slen;
178
179	if (!rcsnum_differ(n1, n2))
180		return (0);
181
182	slen = MIN(n1->rn_len, n2->rn_len);
183	if (depth != 0 && slen > depth)
184		slen = depth;
185
186	for (i = 0; i < slen; i++) {
187		res = n1->rn_id[i] - n2->rn_id[i];
188		if (res < 0)
189			return (1);
190		else if (res > 0)
191			return (-1);
192	}
193
194	if (n1->rn_len > n2->rn_len)
195		return (-1);
196	else if (n2->rn_len > n1->rn_len)
197		return (1);
198
199	return (0);
200}
201
202/*
203 * rcsnum_aton()
204 *
205 * Translate the string <str> containing a sequence of digits and periods into
206 * its binary representation, which is stored in <nump>.  The address of the
207 * first byte not part of the number is stored in <ep> on return, if it is not
208 * NULL.
209 * Returns 0 on success, or -1 on failure.
210 */
211int
212rcsnum_aton(const char *str, char **ep, RCSNUM *nump)
213{
214	u_int32_t val;
215	const char *sp;
216	char *s;
217
218	if (nump->rn_id == NULL)
219		nump->rn_id = xmalloc(sizeof(*(nump->rn_id)));
220
221	nump->rn_len = 0;
222	nump->rn_id[0] = 0;
223
224	for (sp = str;; sp++) {
225		if (!isdigit(*sp) && (*sp != '.'))
226			break;
227
228		if (*sp == '.') {
229			if (nump->rn_len >= RCSNUM_MAXLEN - 1) {
230				rcs_errno = RCS_ERR_BADNUM;
231				goto rcsnum_aton_failed;
232			}
233
234			nump->rn_len++;
235			nump->rn_id = xrealloc(nump->rn_id,
236			    nump->rn_len + 1, sizeof(*(nump->rn_id)));
237			nump->rn_id[nump->rn_len] = 0;
238			continue;
239		}
240
241		val = (nump->rn_id[nump->rn_len] * 10) + (*sp - '0');
242		if (val > RCSNUM_MAXNUM)
243			fatal("RCSNUM overflow!");
244
245		nump->rn_id[nump->rn_len] = val;
246	}
247
248	if (ep != NULL)
249		*(const char **)ep = sp;
250
251	/*
252	 * Handle "magic" RCS branch numbers.
253	 *
254	 * What are they?
255	 *
256	 * Magic branch numbers have an extra .0. at the second farmost
257	 * rightside of the branch number, so instead of having an odd
258	 * number of dot-separated decimals, it will have an even number.
259	 *
260	 * Now, according to all the documentation I've found on the net
261	 * about this, cvs does this for "efficiency reasons", I'd like
262	 * to hear one.
263	 *
264	 * We just make sure we remove the .0. from in the branch number.
265	 *
266	 * XXX - for compatibility reasons with GNU cvs we _need_
267	 * to skip this part for the 'log' command, apparently it does
268	 * show the magic branches for an unknown and probably
269	 * completely insane and not understandable reason in that output.
270	 *
271	 */
272	if (nump->rn_len > 2 && nump->rn_id[nump->rn_len - 1] == 0
273	    && !(rcsnum_flags & RCSNUM_NO_MAGIC)) {
274		/*
275		 * Look for ".0.x" at the end of the branch number.
276		 */
277		if ((s = strrchr(str, '.')) != NULL) {
278			s--;
279			while (*s != '.')
280				s--;
281
282			/*
283			 * If we have a "magic" branch, adjust it
284			 * so the .0. is removed.
285			 */
286			if (!strncmp(s, RCS_MAGIC_BRANCH,
287			    sizeof(RCS_MAGIC_BRANCH) - 1)) {
288				nump->rn_id[nump->rn_len - 1] =
289				    nump->rn_id[nump->rn_len];
290				nump->rn_len--;
291			}
292		}
293	}
294
295	/* We can't have a single-digit rcs number. */
296	if (nump->rn_len == 0) {
297		nump->rn_id = xrealloc(nump->rn_id,
298		    nump->rn_len + 1, sizeof(*(nump->rn_id)));
299		nump->rn_id[nump->rn_len + 1] = 0;
300		nump->rn_len++;
301	}
302
303	nump->rn_len++;
304	return (nump->rn_len);
305
306rcsnum_aton_failed:
307	nump->rn_len = 0;
308	xfree(nump->rn_id);
309	nump->rn_id = NULL;
310	return (-1);
311}
312
313/*
314 * rcsnum_inc()
315 *
316 * Increment the revision number specified in <num>.
317 * Returns a pointer to the <num> on success, or NULL on failure.
318 */
319RCSNUM *
320rcsnum_inc(RCSNUM *num)
321{
322	if (num->rn_id[num->rn_len - 1] == RCSNUM_MAXNUM)
323		return (NULL);
324	num->rn_id[num->rn_len - 1]++;
325	return (num);
326}
327
328/*
329 * rcsnum_dec()
330 *
331 * Decreases the revision number specified in <num>, if doing so will not
332 * result in an ending value below 1. E.g. 4.2 will go to 4.1 but 4.1 will
333 * be returned as 4.1.
334 */
335RCSNUM *
336rcsnum_dec(RCSNUM *num)
337{
338	/* XXX - Is it an error for the number to be 0? */
339	if (num->rn_id[num->rn_len - 1] <= 1)
340		return (num);
341	num->rn_id[num->rn_len - 1]--;
342	return (num);
343}
344
345/*
346 * rcsnum_revtobr()
347 *
348 * Retrieve the branch number associated with the revision number <num>.
349 * If <num> is a branch revision, the returned value will be the same
350 * number as the argument.
351 */
352RCSNUM *
353rcsnum_revtobr(const RCSNUM *num)
354{
355	RCSNUM *brnum;
356
357	if (num->rn_len < 2)
358		return (NULL);
359
360	brnum = rcsnum_alloc();
361	rcsnum_cpy(num, brnum, 0);
362
363	if (!RCSNUM_ISBRANCH(brnum))
364		brnum->rn_len--;
365
366	return (brnum);
367}
368
369/*
370 * rcsnum_brtorev()
371 *
372 * Retrieve the initial revision number associated with the branch number <num>.
373 * If <num> is a revision number, an error will be returned.
374 */
375RCSNUM *
376rcsnum_brtorev(const RCSNUM *brnum)
377{
378	RCSNUM *num;
379
380	if (!RCSNUM_ISBRANCH(brnum)) {
381		return (NULL);
382	}
383
384	num = rcsnum_alloc();
385	rcsnum_setsize(num, brnum->rn_len + 1);
386	rcsnum_cpy(brnum, num, brnum->rn_len);
387	num->rn_id[num->rn_len++] = 1;
388
389	return (num);
390}
391
392static void
393rcsnum_setsize(RCSNUM *num, u_int len)
394{
395	num->rn_id = xrealloc(num->rn_id, len, sizeof(*(num->rn_id)));
396	num->rn_len = len;
397}
398
399int
400rcsnum_differ(RCSNUM *r1, RCSNUM *r2)
401{
402	int i, len;
403
404	if (r1->rn_len != r2->rn_len)
405		return (1);
406
407	len = MIN(r1->rn_len, r2->rn_len);
408	for (i = 0; i < len; i++) {
409		if (r1->rn_id[i] != r2->rn_id[i])
410			return (1);
411	}
412
413	return (0);
414}
415