diffh.c revision 236:cc3576010d16 
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22
23/*
24 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
25 * Use is subject to license terms.
26 */
27
28/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
29/*	  All Rights Reserved  	*/
30
31#pragma ident	"%Z%%M%	%I%	%E% SMI"
32
33#include <stdio.h>
34#include <stdlib.h>
35#include <unistd.h>
36#include <ctype.h>
37#include <locale.h>
38#include <sys/types.h>
39#include <sys/stat.h>
40#include <limits.h>
41#include <stdarg.h>
42
43#define	C		3
44#define	RANGE		30
45#define	LEN		255
46#define	INF		16384
47
48char *text[2][RANGE];
49long lineno[2] = {1, 1};	/* no. of 1st stored line in each file */
50int ntext[2];		/* number of stored lines in each */
51long n0, n1;		/* scan pointer in each */
52int bflag;
53int debug = 0;
54FILE *file[2];
55static int diffFound = 0;
56
57static char *getl(int f, long n);
58static void clrl(int f, long n);
59static void movstr(char *s, char *t);
60static int easysynch(void);
61static int output(int a, int b);
62static void change(long a, int b, long c, int d, char *s);
63static void range(long a, int b);
64static int cmp(char *s, char *t);
65static FILE *dopen(char *f1, char *f2);
66static void progerr(char *s);
67static void error(char *err, ...);
68static int hardsynch(void);
69
70	/* return pointer to line n of file f */
71static char *
72getl(int f, long n)
73{
74	char *t;
75	int delta, nt;
76
77again:
78	delta = n - lineno[f];
79	nt = ntext[f];
80	if (delta < 0)
81		progerr("1");
82	if (delta < nt)
83		return (text[f][delta]);
84	if (delta > nt)
85		progerr("2");
86	if (nt >= RANGE)
87		progerr("3");
88	if (feof(file[f]))
89		return (NULL);
90	t = text[f][nt];
91	if (t == 0) {
92		t = text[f][nt] = (char *)malloc(LEN+1);
93		if (t == NULL)
94			if (hardsynch())
95				goto again;
96			else
97				progerr("5");
98	}
99	t = fgets(t, LEN, file[f]);
100	if (t != NULL)
101		ntext[f]++;
102	return (t);
103}
104
105	/* remove thru line n of file f from storage */
106static void
107clrl(int f, long n)
108{
109	int i, j;
110
111	j = n-lineno[f]+1;
112	for (i = 0; i+j < ntext[f]; i++)
113		movstr(text[f][i+j], text[f][i]);
114	lineno[f] = n+1;
115	ntext[f] -= j;
116}
117
118static void
119movstr(char *s, char *t)
120{
121	while (*t++ = *s++)
122		continue;
123}
124
125int
126main(int argc, char **argv)
127{
128	char *s0, *s1;
129
130	if ((argc > 1) && (*argv[1] == '-')) {
131		argc--;
132		argv++;
133		while (*++argv[0])
134			if (*argv[0] == 'b')
135				bflag++;
136	}
137
138	(void) setlocale(LC_ALL, "");
139#if !defined(TEXT_DOMAIN)		/* Should be defined by cc -D */
140#define	TEXT_DOMAIN	"SYS_TEST"	/* Use this only if it weren't */
141#endif
142	(void) textdomain(TEXT_DOMAIN);
143
144	if (argc != 3)
145		error(gettext("must have 2 file arguments"));
146	file[0] = dopen(argv[1], argv[2]);
147	file[1] = dopen(argv[2], argv[1]);
148	for (;;) {
149		s0 = getl(0, ++n0);
150		s1 = getl(1, ++n1);
151		if (s0 == NULL || s1 == NULL)
152			break;
153		if (cmp(s0, s1) != 0) {
154			if (!easysynch() && !hardsynch())
155				progerr("5");
156		} else {
157			clrl(0, n0);
158			clrl(1, n1);
159		}
160	}
161	/* diff is expected to return 1 if the files differ */
162	if (s0 == NULL && s1 == NULL)
163		return (diffFound);
164	if (s0 == NULL) {
165		(void) output(-1, INF);
166		return (1);
167	}
168	if (s1 == NULL) {
169		(void) output(INF, -1);
170		return (1);
171	}
172	/* NOTREACHED */
173	return (0);
174}
175
176	/* synch on C successive matches */
177static int
178easysynch()
179{
180	int i, j;
181	int k, m;
182	char *s0, *s1;
183
184	for (i = j = 1; i < RANGE && j < RANGE; i++, j++) {
185		s0 = getl(0, n0+i);
186		if (s0 == NULL)
187			return (output(INF, INF));
188		for (k = C-1; k < j; k++) {
189			for (m = 0; m < C; m++)
190				if (cmp(getl(0, n0+i-m),
191					getl(1, n1+k-m)) != 0)
192					goto cont1;
193			return (output(i-C, k-C));
194cont1:
195			;
196		}
197		s1 = getl(1, n1+j);
198		if (s1 == NULL)
199			return (output(INF, INF));
200		for (k = C-1; k <= i; k++) {
201			for (m = 0; m < C; m++)
202				if (cmp(getl(0, n0+k-m),
203					getl(1, n1+j-m)) != 0)
204					goto cont2;
205			return (output(k-C, j-C));
206cont2:
207			;
208		}
209	}
210	return (0);
211}
212
213static int
214output(int a, int b)
215{
216	int i;
217	char *s;
218
219	if (a < 0)
220		change(n0-1, 0, n1, b, "a");
221	else if (b < 0)
222		change(n0, a, n1-1, 0, "d");
223	else
224		change(n0, a, n1, b, "c");
225	for (i = 0; i <= a; i++) {
226		s = getl(0, n0+i);
227		if (s == NULL)
228			break;
229		(void) printf("< %s", s);
230		clrl(0, n0+i);
231	}
232	n0 += i-1;
233	if (a >= 0 && b >= 0)
234		(void) printf("---\n");
235	for (i = 0; i <= b; i++) {
236		s = getl(1, n1+i);
237		if (s == NULL)
238			break;
239		(void) printf("> %s", s);
240		clrl(1, n1+i);
241	}
242	diffFound = 1;
243	n1 += i-1;
244	return (1);
245}
246
247static void
248change(long a, int b, long c, int d, char *s)
249{
250	range(a, b);
251	(void) printf("%s", s);
252	range(c, d);
253	(void) printf("\n");
254}
255
256static void
257range(long a, int b)
258{
259	if (b == INF)
260		(void) printf("%ld,$", a);
261	else if (b == 0)
262		(void) printf("%ld", a);
263	else
264		(void) printf("%ld,%ld", a, a+b);
265}
266
267static int
268cmp(char *s, char *t)
269{
270	if (debug)
271		(void) printf("%s:%s\n", s, t);
272	for (;;) {
273		if (bflag && isspace(*s) && isspace(*t)) {
274			while (isspace(*++s))
275				;
276			while (isspace(*++t))
277				;
278		}
279		if (*s != *t || *s == 0)
280			break;
281		s++;
282		t++;
283	}
284	return (*s-*t);
285}
286
287static FILE *
288dopen(char *f1, char *f2)
289{
290	FILE *f;
291	char b[PATH_MAX], *bptr, *eptr;
292	struct stat statbuf;
293
294	if (cmp(f1, "-") == 0) {
295		if (cmp(f2, "-") == 0)
296			error(gettext("can't do - -"));
297		else {
298			if (fstat(fileno(stdin), &statbuf) == -1)
299				error(gettext("can't access stdin"));
300			else
301				return (stdin);
302		}
303	}
304	if (stat(f1, &statbuf) == -1)
305		error(gettext("can't access %s"), f1);
306	if ((statbuf.st_mode & S_IFMT) == S_IFDIR) {
307		for (bptr = b; *bptr = *f1++; bptr++)
308			;
309		*bptr++ = '/';
310		for (eptr = f2; *eptr; eptr++)
311			if (*eptr == '/' && eptr[1] != 0 && eptr[1] != '/')
312				f2 = eptr+1;
313		while (*bptr++ = *f2++)
314			;
315		f1 = b;
316	}
317	f = fopen(f1, "r");
318	if (f == NULL)
319		error(gettext("can't open %s"), f1);
320	return (f);
321}
322
323
324static void
325progerr(char *s)
326{
327	error(gettext("program error %s"), s);
328}
329
330static void
331error(char *err, ...)
332{
333	va_list	ap;
334
335	va_start(ap, err);
336	(void) fprintf(stderr, "diffh: ");
337	(void) vfprintf(stderr, err, ap);
338	(void) fprintf(stderr, "\n");
339	va_end(ap);
340	exit(2);
341}
342
343	/* stub for resychronization beyond limits of text buf */
344static int
345hardsynch()
346{
347	change(n0, INF, n1, INF, "c");
348	(void) printf(gettext("---change record omitted\n"));
349	error(gettext("can't resynchronize"));
350	return (0);
351}
352