1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
23*0Sstevel@tonic-gate /*	  All Rights Reserved  	*/
24*0Sstevel@tonic-gate 
25*0Sstevel@tonic-gate 
26*0Sstevel@tonic-gate /*
27*0Sstevel@tonic-gate  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
28*0Sstevel@tonic-gate  * Use is subject to license terms.
29*0Sstevel@tonic-gate  */
30*0Sstevel@tonic-gate 
31*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
32*0Sstevel@tonic-gate 
33*0Sstevel@tonic-gate #include <stdio.h>
34*0Sstevel@tonic-gate #include <stdlib.h>
35*0Sstevel@tonic-gate #include <unistd.h>
36*0Sstevel@tonic-gate #include <limits.h>
37*0Sstevel@tonic-gate #include <sys/param.h>
38*0Sstevel@tonic-gate #include <errno.h>
39*0Sstevel@tonic-gate #
40*0Sstevel@tonic-gate 
41*0Sstevel@tonic-gate /*
42*0Sstevel@tonic-gate  * diff3 - 3-way differential file comparison
43*0Sstevel@tonic-gate  */
44*0Sstevel@tonic-gate 
45*0Sstevel@tonic-gate /*
46*0Sstevel@tonic-gate  * diff3 [-ex3EX] d13 d23 f1 f2 f3 [m1 m3]
47*0Sstevel@tonic-gate  *
48*0Sstevel@tonic-gate  * d13 = diff report on f1 vs f3
49*0Sstevel@tonic-gate  * d23 = diff report on f2 vs f3
50*0Sstevel@tonic-gate  * f1, f2, f3 the 3 files
51*0Sstevel@tonic-gate  * if changes in f1 overlap with changes in f3, m1 and m3 are used
52*0Sstevel@tonic-gate  * to mark the overlaps; otherwise, the file names f1 and f3 are used
53*0Sstevel@tonic-gate  * (only for options E and X).
54*0Sstevel@tonic-gate  */
55*0Sstevel@tonic-gate 
56*0Sstevel@tonic-gate struct  range {int from, to; };
57*0Sstevel@tonic-gate 	/*
58*0Sstevel@tonic-gate 	 * from is first in range of changed lines
59*0Sstevel@tonic-gate 	 * to is last+1
60*0Sstevel@tonic-gate 	 * from = to = line after point of insertion
61*0Sstevel@tonic-gate 	 * for added lines
62*0Sstevel@tonic-gate 	 */
63*0Sstevel@tonic-gate struct diff {struct range old, new; };
64*0Sstevel@tonic-gate 
65*0Sstevel@tonic-gate #define	NC 4096
66*0Sstevel@tonic-gate /*
67*0Sstevel@tonic-gate  * de is used to gather editing scripts,
68*0Sstevel@tonic-gate  * that are later spewed out in reverse order.
69*0Sstevel@tonic-gate  * its first element must be all zero
70*0Sstevel@tonic-gate  * the "new" component of de contains line positions
71*0Sstevel@tonic-gate  * or byte positions depending on when you look(!?)
72*0Sstevel@tonic-gate  */
73*0Sstevel@tonic-gate static struct diff d13[NC];
74*0Sstevel@tonic-gate static struct diff d23[NC];
75*0Sstevel@tonic-gate 
76*0Sstevel@tonic-gate /*
77*0Sstevel@tonic-gate  * array overlap indicates which sections in de correspond to
78*0Sstevel@tonic-gate  * lines that are different in all three files.
79*0Sstevel@tonic-gate  */
80*0Sstevel@tonic-gate 
81*0Sstevel@tonic-gate static struct diff de[NC];
82*0Sstevel@tonic-gate static char overlap[NC];
83*0Sstevel@tonic-gate static int  overlapcnt = 0;
84*0Sstevel@tonic-gate 
85*0Sstevel@tonic-gate static char line[LINE_MAX+1];
86*0Sstevel@tonic-gate static FILE *fp[3];
87*0Sstevel@tonic-gate /*
88*0Sstevel@tonic-gate  *	the number of the last-read line in each file
89*0Sstevel@tonic-gate  *	is kept in cline[0-2]
90*0Sstevel@tonic-gate  */
91*0Sstevel@tonic-gate static int cline[3];
92*0Sstevel@tonic-gate /*
93*0Sstevel@tonic-gate  *	the latest known correspondence between line
94*0Sstevel@tonic-gate  *	numbers of the 3 files is stored in last[1-3]
95*0Sstevel@tonic-gate  */
96*0Sstevel@tonic-gate static int last[4];
97*0Sstevel@tonic-gate static int eflag;
98*0Sstevel@tonic-gate static int oflag;	/* indicates whether to mark overlaps (-E or -X) */
99*0Sstevel@tonic-gate static int debug  = 0;
100*0Sstevel@tonic-gate /* markers for -E and -X: */
101*0Sstevel@tonic-gate static char f1mark[8+MAXPATHLEN], f3mark[8+MAXPATHLEN];
102*0Sstevel@tonic-gate 		/* Need space for "<<<<<<< " or ">>>>>>> " plus filename   */
103*0Sstevel@tonic-gate static int save_err;	/* saves errno */
104*0Sstevel@tonic-gate 
105*0Sstevel@tonic-gate static int readin(char *name, struct diff *dd);
106*0Sstevel@tonic-gate static int number(char **lc);
107*0Sstevel@tonic-gate static int digit(int c);
108*0Sstevel@tonic-gate static int getchange(FILE *b);
109*0Sstevel@tonic-gate static int getline(FILE *b);
110*0Sstevel@tonic-gate static void merge(int m1, int m2);
111*0Sstevel@tonic-gate static void separate(char *s);
112*0Sstevel@tonic-gate static void change(int i, struct range *rold, int dup);
113*0Sstevel@tonic-gate static void prange(struct range *rold);
114*0Sstevel@tonic-gate static void keep(int i, struct range *rnew);
115*0Sstevel@tonic-gate static int skip(int i, int from, char *pr);
116*0Sstevel@tonic-gate static int duplicate(struct range *r1, struct range *r2);
117*0Sstevel@tonic-gate static void repos(int nchar);
118*0Sstevel@tonic-gate static void trouble();
119*0Sstevel@tonic-gate static int edit(struct diff *diff, int dup, int j);
120*0Sstevel@tonic-gate static void edscript(int n);
121*0Sstevel@tonic-gate 
122*0Sstevel@tonic-gate int
123*0Sstevel@tonic-gate main(int argc, char **argv)
124*0Sstevel@tonic-gate {
125*0Sstevel@tonic-gate 	int i, m, n;
126*0Sstevel@tonic-gate 	eflag  = 0;
127*0Sstevel@tonic-gate 	oflag  = 0;
128*0Sstevel@tonic-gate 	if (*argv[1] == '-') {
129*0Sstevel@tonic-gate 		switch (argv[1][1]) {
130*0Sstevel@tonic-gate 		default:
131*0Sstevel@tonic-gate 			eflag = 3;
132*0Sstevel@tonic-gate 			break;
133*0Sstevel@tonic-gate 		case '3':
134*0Sstevel@tonic-gate 			eflag = 2;
135*0Sstevel@tonic-gate 			break;
136*0Sstevel@tonic-gate 		case 'x':
137*0Sstevel@tonic-gate 			eflag = 1;
138*0Sstevel@tonic-gate 			break;
139*0Sstevel@tonic-gate 		case 'E':
140*0Sstevel@tonic-gate 			eflag = 3;
141*0Sstevel@tonic-gate 			oflag = 1;
142*0Sstevel@tonic-gate 			break;
143*0Sstevel@tonic-gate 		case 'X':
144*0Sstevel@tonic-gate 			oflag = eflag = 1;
145*0Sstevel@tonic-gate 			break;
146*0Sstevel@tonic-gate 		}
147*0Sstevel@tonic-gate 		argv++;
148*0Sstevel@tonic-gate 		argc--;
149*0Sstevel@tonic-gate 	}
150*0Sstevel@tonic-gate 	if (argc < 6) {
151*0Sstevel@tonic-gate 		(void) fprintf(stderr, "diff3: arg count\n");
152*0Sstevel@tonic-gate 		exit(1);
153*0Sstevel@tonic-gate 	}
154*0Sstevel@tonic-gate 
155*0Sstevel@tonic-gate 	if (oflag) {
156*0Sstevel@tonic-gate 		(void) snprintf(f1mark, sizeof (f1mark), "<<<<<<< %s",
157*0Sstevel@tonic-gate 						argc >= 7 ? argv[6] : argv[3]);
158*0Sstevel@tonic-gate 		(void) snprintf(f3mark, sizeof (f3mark), ">>>>>>> %s",
159*0Sstevel@tonic-gate 						argc >= 8 ? argv[7] : argv[5]);
160*0Sstevel@tonic-gate 	}
161*0Sstevel@tonic-gate 
162*0Sstevel@tonic-gate 	m = readin(argv[1], d13);
163*0Sstevel@tonic-gate 	n = readin(argv[2], d23);
164*0Sstevel@tonic-gate 	for (i = 0; i <= 2; i++)
165*0Sstevel@tonic-gate 		if ((fp[i] = fopen(argv[i+3], "r")) == NULL) {
166*0Sstevel@tonic-gate 			save_err = errno;
167*0Sstevel@tonic-gate 			(void) fprintf(stderr, "diff3: can't open %s: ",
168*0Sstevel@tonic-gate 				argv[i+3]);
169*0Sstevel@tonic-gate 			errno = save_err;
170*0Sstevel@tonic-gate 			perror("");
171*0Sstevel@tonic-gate 			exit(1);
172*0Sstevel@tonic-gate 		}
173*0Sstevel@tonic-gate 	merge(m, n);
174*0Sstevel@tonic-gate 	return (0);
175*0Sstevel@tonic-gate }
176*0Sstevel@tonic-gate 
177*0Sstevel@tonic-gate /*
178*0Sstevel@tonic-gate  * pick up the line numbers of all changes from
179*0Sstevel@tonic-gate  * one change file
180*0Sstevel@tonic-gate  * (this puts the numbers in a vector, which is not
181*0Sstevel@tonic-gate  * strictly necessary, since the vector is processed
182*0Sstevel@tonic-gate  * in one sequential pass. The vector could be optimized
183*0Sstevel@tonic-gate  * out of existence)
184*0Sstevel@tonic-gate  */
185*0Sstevel@tonic-gate 
186*0Sstevel@tonic-gate static int
187*0Sstevel@tonic-gate readin(char *name, struct diff *dd)
188*0Sstevel@tonic-gate {
189*0Sstevel@tonic-gate 	int i;
190*0Sstevel@tonic-gate 	int a, b, c, d;
191*0Sstevel@tonic-gate 	char kind;
192*0Sstevel@tonic-gate 	char *p;
193*0Sstevel@tonic-gate 	if ((fp[0] = fopen(name, "r")) == NULL) {
194*0Sstevel@tonic-gate 		save_err = errno;
195*0Sstevel@tonic-gate 		(void) fprintf(stderr, "diff3: can't open %s: ", name);
196*0Sstevel@tonic-gate 		errno = save_err;
197*0Sstevel@tonic-gate 		perror("");
198*0Sstevel@tonic-gate 		exit(1);
199*0Sstevel@tonic-gate 	}
200*0Sstevel@tonic-gate 	for (i = 0; getchange(fp[0]); i++) {
201*0Sstevel@tonic-gate 		if (i >= NC) {
202*0Sstevel@tonic-gate 			(void) fprintf(stderr, "diff3: too many changes\n");
203*0Sstevel@tonic-gate 			exit(0);
204*0Sstevel@tonic-gate 		}
205*0Sstevel@tonic-gate 		p = line;
206*0Sstevel@tonic-gate 		a = b = number(&p);
207*0Sstevel@tonic-gate 		if (*p == ',') {
208*0Sstevel@tonic-gate 			p++;
209*0Sstevel@tonic-gate 			b = number(&p);
210*0Sstevel@tonic-gate 		}
211*0Sstevel@tonic-gate 		kind = *p++;
212*0Sstevel@tonic-gate 		c = d = number(&p);
213*0Sstevel@tonic-gate 		if (*p == ',') {
214*0Sstevel@tonic-gate 			p++;
215*0Sstevel@tonic-gate 			d = number(&p);
216*0Sstevel@tonic-gate 		}
217*0Sstevel@tonic-gate 		if (kind == 'a')
218*0Sstevel@tonic-gate 			a++;
219*0Sstevel@tonic-gate 		if (kind == 'd')
220*0Sstevel@tonic-gate 			c++;
221*0Sstevel@tonic-gate 		b++;
222*0Sstevel@tonic-gate 		d++;
223*0Sstevel@tonic-gate 		dd[i].old.from = a;
224*0Sstevel@tonic-gate 		dd[i].old.to = b;
225*0Sstevel@tonic-gate 		dd[i].new.from = c;
226*0Sstevel@tonic-gate 		dd[i].new.to = d;
227*0Sstevel@tonic-gate 	}
228*0Sstevel@tonic-gate 	dd[i].old.from = dd[i-1].old.to;
229*0Sstevel@tonic-gate 	dd[i].new.from = dd[i-1].new.to;
230*0Sstevel@tonic-gate 	(void) fclose(fp[0]);
231*0Sstevel@tonic-gate 	return (i);
232*0Sstevel@tonic-gate }
233*0Sstevel@tonic-gate 
234*0Sstevel@tonic-gate static int
235*0Sstevel@tonic-gate number(char **lc)
236*0Sstevel@tonic-gate {
237*0Sstevel@tonic-gate 	int nn;
238*0Sstevel@tonic-gate 	nn = 0;
239*0Sstevel@tonic-gate 	while (digit(**lc))
240*0Sstevel@tonic-gate 		nn = nn*10 + *(*lc)++ - '0';
241*0Sstevel@tonic-gate 	return (nn);
242*0Sstevel@tonic-gate }
243*0Sstevel@tonic-gate 
244*0Sstevel@tonic-gate static int
245*0Sstevel@tonic-gate digit(int c)
246*0Sstevel@tonic-gate {
247*0Sstevel@tonic-gate 	return (c >= '0' && c <= '9');
248*0Sstevel@tonic-gate }
249*0Sstevel@tonic-gate 
250*0Sstevel@tonic-gate static int
251*0Sstevel@tonic-gate getchange(FILE *b)
252*0Sstevel@tonic-gate {
253*0Sstevel@tonic-gate 	while (getline(b))
254*0Sstevel@tonic-gate 		if (digit(line[0]))
255*0Sstevel@tonic-gate 			return (1);
256*0Sstevel@tonic-gate 	return (0);
257*0Sstevel@tonic-gate }
258*0Sstevel@tonic-gate 
259*0Sstevel@tonic-gate static int
260*0Sstevel@tonic-gate getline(FILE *b)
261*0Sstevel@tonic-gate {
262*0Sstevel@tonic-gate 	int i, c;
263*0Sstevel@tonic-gate 	for (i = 0; i < sizeof (line)-1; i++) {
264*0Sstevel@tonic-gate 		c = getc(b);
265*0Sstevel@tonic-gate 		if (c == EOF) {
266*0Sstevel@tonic-gate 			line[i] = 0;
267*0Sstevel@tonic-gate 			return (i);
268*0Sstevel@tonic-gate 		}
269*0Sstevel@tonic-gate 		line[i] = c;
270*0Sstevel@tonic-gate 		if (c == '\n') {
271*0Sstevel@tonic-gate 			line[++i] = 0;
272*0Sstevel@tonic-gate 			return (i);
273*0Sstevel@tonic-gate 		}
274*0Sstevel@tonic-gate 	}
275*0Sstevel@tonic-gate 	return (0);
276*0Sstevel@tonic-gate }
277*0Sstevel@tonic-gate 
278*0Sstevel@tonic-gate static void
279*0Sstevel@tonic-gate merge(int m1, int m2)
280*0Sstevel@tonic-gate {
281*0Sstevel@tonic-gate 	struct diff *d1, *d2, *d3;
282*0Sstevel@tonic-gate 	int dup;
283*0Sstevel@tonic-gate 	int j;
284*0Sstevel@tonic-gate 	int t1, t2;
285*0Sstevel@tonic-gate 	d1 = d13;
286*0Sstevel@tonic-gate 	d2 = d23;
287*0Sstevel@tonic-gate 	j = 0;
288*0Sstevel@tonic-gate 	for (; (t1 = d1 < d13+m1) | (t2 = d2 < d23+m2); ) {
289*0Sstevel@tonic-gate 		if (debug) {
290*0Sstevel@tonic-gate 			(void) printf("%d,%d=%d,%d %d,%d=%d,%d\n",
291*0Sstevel@tonic-gate 			d1->old.from, d1->old.to,
292*0Sstevel@tonic-gate 			d1->new.from, d1->new.to,
293*0Sstevel@tonic-gate 			d2->old.from, d2->old.to,
294*0Sstevel@tonic-gate 			d2->new.from, d2->new.to);
295*0Sstevel@tonic-gate 		}
296*0Sstevel@tonic-gate 
297*0Sstevel@tonic-gate 		/* first file is different from others */
298*0Sstevel@tonic-gate 		if (!t2 || t1 && d1->new.to < d2->new.from) {
299*0Sstevel@tonic-gate 			/* stuff peculiar to 1st file */
300*0Sstevel@tonic-gate 			if (eflag == 0) {
301*0Sstevel@tonic-gate 				separate("1");
302*0Sstevel@tonic-gate 				change(1, &d1->old, 0);
303*0Sstevel@tonic-gate 				keep(2, &d1->new);
304*0Sstevel@tonic-gate 				change(3, &d1->new, 0);
305*0Sstevel@tonic-gate 			}
306*0Sstevel@tonic-gate 			d1++;
307*0Sstevel@tonic-gate 			continue;
308*0Sstevel@tonic-gate 		}
309*0Sstevel@tonic-gate 
310*0Sstevel@tonic-gate 		/* second file is different from others */
311*0Sstevel@tonic-gate 		if (!t1 || t2 && d2->new.to < d1->new.from) {
312*0Sstevel@tonic-gate 			if (eflag == 0) {
313*0Sstevel@tonic-gate 				separate("2");
314*0Sstevel@tonic-gate 				keep(1, &d2->new);
315*0Sstevel@tonic-gate 				change(2, &d2->old, 0);
316*0Sstevel@tonic-gate 				change(3, &d2->new, 0);
317*0Sstevel@tonic-gate 			}
318*0Sstevel@tonic-gate 			d2++;
319*0Sstevel@tonic-gate 			continue;
320*0Sstevel@tonic-gate 		}
321*0Sstevel@tonic-gate 		/*
322*0Sstevel@tonic-gate 		 * merge overlapping changes in first file
323*0Sstevel@tonic-gate 		 * this happens after extension see below
324*0Sstevel@tonic-gate 		 */
325*0Sstevel@tonic-gate 		if (d1+1 < d13+m1 && d1->new.to >= d1[1].new.from) {
326*0Sstevel@tonic-gate 			d1[1].old.from = d1->old.from;
327*0Sstevel@tonic-gate 			d1[1].new.from = d1->new.from;
328*0Sstevel@tonic-gate 			d1++;
329*0Sstevel@tonic-gate 			continue;
330*0Sstevel@tonic-gate 		}
331*0Sstevel@tonic-gate 
332*0Sstevel@tonic-gate 		/* merge overlapping changes in second */
333*0Sstevel@tonic-gate 		if (d2+1 < d23+m2 && d2->new.to >= d2[1].new.from) {
334*0Sstevel@tonic-gate 			d2[1].old.from = d2->old.from;
335*0Sstevel@tonic-gate 			d2[1].new.from = d2->new.from;
336*0Sstevel@tonic-gate 			d2++;
337*0Sstevel@tonic-gate 			continue;
338*0Sstevel@tonic-gate 		}
339*0Sstevel@tonic-gate 
340*0Sstevel@tonic-gate 		/* stuff peculiar to third file or different in all */
341*0Sstevel@tonic-gate 		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
342*0Sstevel@tonic-gate 			dup = duplicate(&d1->old, &d2->old);
343*0Sstevel@tonic-gate 			/*
344*0Sstevel@tonic-gate 			 * dup = 0 means all files differ
345*0Sstevel@tonic-gate 			 * dup = 1 meands files 1&2 identical
346*0Sstevel@tonic-gate 			 */
347*0Sstevel@tonic-gate 			if (eflag == 0) {
348*0Sstevel@tonic-gate 				separate(dup?"3":"");
349*0Sstevel@tonic-gate 				change(1, &d1->old, dup);
350*0Sstevel@tonic-gate 				change(2, &d2->old, 0);
351*0Sstevel@tonic-gate 				d3 = d1->old.to > d1->old.from ? d1 : d2;
352*0Sstevel@tonic-gate 				change(3, &d3->new, 0);
353*0Sstevel@tonic-gate 			} else
354*0Sstevel@tonic-gate 				j = edit(d1, dup, j);
355*0Sstevel@tonic-gate 			d1++;
356*0Sstevel@tonic-gate 			d2++;
357*0Sstevel@tonic-gate 			continue;
358*0Sstevel@tonic-gate 		}
359*0Sstevel@tonic-gate 		/*
360*0Sstevel@tonic-gate 		 * overlapping changes from file1 & 2
361*0Sstevel@tonic-gate 		 * extend changes appropriately to
362*0Sstevel@tonic-gate 		 * make them coincide
363*0Sstevel@tonic-gate 		 */
364*0Sstevel@tonic-gate 		if (d1->new.from < d2->new.from) {
365*0Sstevel@tonic-gate 			d2->old.from -= d2->new.from-d1->new.from;
366*0Sstevel@tonic-gate 			d2->new.from = d1->new.from;
367*0Sstevel@tonic-gate 		} else if (d2->new.from < d1->new.from) {
368*0Sstevel@tonic-gate 			d1->old.from -= d1->new.from-d2->new.from;
369*0Sstevel@tonic-gate 			d1->new.from = d2->new.from;
370*0Sstevel@tonic-gate 		}
371*0Sstevel@tonic-gate 
372*0Sstevel@tonic-gate 		if (d1->new.to > d2->new.to) {
373*0Sstevel@tonic-gate 			d2->old.to += d1->new.to - d2->new.to;
374*0Sstevel@tonic-gate 			d2->new.to = d1->new.to;
375*0Sstevel@tonic-gate 		} else if (d2->new.to > d1->new.to) {
376*0Sstevel@tonic-gate 			d1->old.to += d2->new.to - d1->new.to;
377*0Sstevel@tonic-gate 			d1->new.to = d2->new.to;
378*0Sstevel@tonic-gate 		}
379*0Sstevel@tonic-gate 	}
380*0Sstevel@tonic-gate 	if (eflag) {
381*0Sstevel@tonic-gate 		edscript(j);
382*0Sstevel@tonic-gate 		if (j)
383*0Sstevel@tonic-gate 			(void) printf("w\nq\n");
384*0Sstevel@tonic-gate 	}
385*0Sstevel@tonic-gate }
386*0Sstevel@tonic-gate 
387*0Sstevel@tonic-gate static void
388*0Sstevel@tonic-gate separate(char *s)
389*0Sstevel@tonic-gate {
390*0Sstevel@tonic-gate 	(void) printf("====%s\n", s);
391*0Sstevel@tonic-gate }
392*0Sstevel@tonic-gate 
393*0Sstevel@tonic-gate /*
394*0Sstevel@tonic-gate  * the range of ines rold.from thru rold.to in file i
395*0Sstevel@tonic-gate  * is to be changed. it is to be printed only if
396*0Sstevel@tonic-gate  * it does not duplicate something to be printed later
397*0Sstevel@tonic-gate  */
398*0Sstevel@tonic-gate static void
399*0Sstevel@tonic-gate change(int i, struct range *rold, int dup)
400*0Sstevel@tonic-gate {
401*0Sstevel@tonic-gate 	(void) printf("%d:", i);
402*0Sstevel@tonic-gate 	last[i] = rold->to;
403*0Sstevel@tonic-gate 	prange(rold);
404*0Sstevel@tonic-gate 	if (dup)
405*0Sstevel@tonic-gate 		return;
406*0Sstevel@tonic-gate 	if (debug)
407*0Sstevel@tonic-gate 		return;
408*0Sstevel@tonic-gate 	i--;
409*0Sstevel@tonic-gate 	(void) skip(i, rold->from, (char *)0);
410*0Sstevel@tonic-gate 	(void) skip(i, rold->to, "  ");
411*0Sstevel@tonic-gate }
412*0Sstevel@tonic-gate 
413*0Sstevel@tonic-gate /*
414*0Sstevel@tonic-gate  * print the range of line numbers, rold.from  thru rold.to
415*0Sstevel@tonic-gate  * as n1, n2 or n1
416*0Sstevel@tonic-gate  */
417*0Sstevel@tonic-gate static void
418*0Sstevel@tonic-gate prange(struct range *rold)
419*0Sstevel@tonic-gate {
420*0Sstevel@tonic-gate 	if (rold->to <= rold->from)
421*0Sstevel@tonic-gate 		(void) printf("%da\n", rold->from-1);
422*0Sstevel@tonic-gate 	else {
423*0Sstevel@tonic-gate 		(void) printf("%d", rold->from);
424*0Sstevel@tonic-gate 		if (rold->to > rold->from+1)
425*0Sstevel@tonic-gate 			(void) printf(",%d", rold->to-1);
426*0Sstevel@tonic-gate 		(void) printf("c\n");
427*0Sstevel@tonic-gate 	}
428*0Sstevel@tonic-gate }
429*0Sstevel@tonic-gate 
430*0Sstevel@tonic-gate /*
431*0Sstevel@tonic-gate  * no difference was reported by diff between file 1(or 2)
432*0Sstevel@tonic-gate  * and file 3, and an artificial dummy difference (trange)
433*0Sstevel@tonic-gate  * must be ginned up to correspond to the change reported
434*0Sstevel@tonic-gate  * in the other file
435*0Sstevel@tonic-gate  */
436*0Sstevel@tonic-gate static void
437*0Sstevel@tonic-gate keep(int i, struct range *rnew)
438*0Sstevel@tonic-gate {
439*0Sstevel@tonic-gate 	int delta;
440*0Sstevel@tonic-gate 	struct range trange;
441*0Sstevel@tonic-gate 	delta = last[3] - last[i];
442*0Sstevel@tonic-gate 	trange.from = rnew->from - delta;
443*0Sstevel@tonic-gate 	trange.to = rnew->to - delta;
444*0Sstevel@tonic-gate 	change(i, &trange, 1);
445*0Sstevel@tonic-gate }
446*0Sstevel@tonic-gate 
447*0Sstevel@tonic-gate /*
448*0Sstevel@tonic-gate  * skip to just befor line number from in file i
449*0Sstevel@tonic-gate  * if "pr" is nonzero, print all skipped stuff
450*0Sstevel@tonic-gate  * with string pr as a prefix
451*0Sstevel@tonic-gate  */
452*0Sstevel@tonic-gate static int
453*0Sstevel@tonic-gate skip(int i, int from, char *pr)
454*0Sstevel@tonic-gate {
455*0Sstevel@tonic-gate 	int j, n;
456*0Sstevel@tonic-gate 	for (n = 0; cline[i] < from-1; n += j) {
457*0Sstevel@tonic-gate 		if ((j = getline(fp[i])) == 0)
458*0Sstevel@tonic-gate 			trouble();
459*0Sstevel@tonic-gate 		if (pr)
460*0Sstevel@tonic-gate 			(void) printf("%s%s", pr, line);
461*0Sstevel@tonic-gate 		cline[i]++;
462*0Sstevel@tonic-gate 	}
463*0Sstevel@tonic-gate 	return (n);
464*0Sstevel@tonic-gate }
465*0Sstevel@tonic-gate 
466*0Sstevel@tonic-gate /*
467*0Sstevel@tonic-gate  * return 1 or 0 according as the old range
468*0Sstevel@tonic-gate  * (in file 1) contains exactly the same data
469*0Sstevel@tonic-gate  * as the new range (in file 2)
470*0Sstevel@tonic-gate  */
471*0Sstevel@tonic-gate static int
472*0Sstevel@tonic-gate duplicate(struct range *r1, struct range *r2)
473*0Sstevel@tonic-gate {
474*0Sstevel@tonic-gate 	int c, d;
475*0Sstevel@tonic-gate 	int nchar;
476*0Sstevel@tonic-gate 	int nline;
477*0Sstevel@tonic-gate 	if (r1->to-r1->from != r2->to-r2->from)
478*0Sstevel@tonic-gate 		return (0);
479*0Sstevel@tonic-gate 	(void) skip(0, r1->from, (char *)0);
480*0Sstevel@tonic-gate 	(void) skip(1, r2->from, (char *)0);
481*0Sstevel@tonic-gate 	nchar = 0;
482*0Sstevel@tonic-gate 	for (nline = 0; nline < r1->to-r1->from; nline++) {
483*0Sstevel@tonic-gate 		do {
484*0Sstevel@tonic-gate 			c = getc(fp[0]);
485*0Sstevel@tonic-gate 			d = getc(fp[1]);
486*0Sstevel@tonic-gate 			if (c == -1 || d == -1)
487*0Sstevel@tonic-gate 				trouble();
488*0Sstevel@tonic-gate 			nchar++;
489*0Sstevel@tonic-gate 			if (c != d) {
490*0Sstevel@tonic-gate 				repos(nchar);
491*0Sstevel@tonic-gate 				return (0);
492*0Sstevel@tonic-gate 			}
493*0Sstevel@tonic-gate 		} while (c != '\n');
494*0Sstevel@tonic-gate 	}
495*0Sstevel@tonic-gate 	repos(nchar);
496*0Sstevel@tonic-gate 	return (1);
497*0Sstevel@tonic-gate }
498*0Sstevel@tonic-gate 
499*0Sstevel@tonic-gate static void
500*0Sstevel@tonic-gate repos(int nchar)
501*0Sstevel@tonic-gate {
502*0Sstevel@tonic-gate 	int i;
503*0Sstevel@tonic-gate 	for (i = 0; i < 2; i++)
504*0Sstevel@tonic-gate 		(void) fseek(fp[i], (long)-nchar, 1);
505*0Sstevel@tonic-gate }
506*0Sstevel@tonic-gate 
507*0Sstevel@tonic-gate static void
508*0Sstevel@tonic-gate trouble()
509*0Sstevel@tonic-gate {
510*0Sstevel@tonic-gate 	(void) fprintf(stderr, "diff3: logic error\n");
511*0Sstevel@tonic-gate 	abort();
512*0Sstevel@tonic-gate }
513*0Sstevel@tonic-gate 
514*0Sstevel@tonic-gate /*
515*0Sstevel@tonic-gate  * collect an editing script for later regurgitation
516*0Sstevel@tonic-gate  */
517*0Sstevel@tonic-gate static int
518*0Sstevel@tonic-gate edit(struct diff *diff, int dup, int j)
519*0Sstevel@tonic-gate {
520*0Sstevel@tonic-gate 	if (((dup+1)&eflag) == 0)
521*0Sstevel@tonic-gate 		return (j);
522*0Sstevel@tonic-gate 	j++;
523*0Sstevel@tonic-gate 	overlap[j] = !dup;
524*0Sstevel@tonic-gate 	if (!dup) overlapcnt++;
525*0Sstevel@tonic-gate 	de[j].old.from = diff->old.from;
526*0Sstevel@tonic-gate 	de[j].old.to = diff->old.to;
527*0Sstevel@tonic-gate 	de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, (char *)0);
528*0Sstevel@tonic-gate 	de[j].new.to = de[j].new.from + skip(2, diff->new.to, (char *)0);
529*0Sstevel@tonic-gate 	return (j);
530*0Sstevel@tonic-gate }
531*0Sstevel@tonic-gate 
532*0Sstevel@tonic-gate /*		regurgitate */
533*0Sstevel@tonic-gate static void
534*0Sstevel@tonic-gate edscript(int n)
535*0Sstevel@tonic-gate {
536*0Sstevel@tonic-gate 	int j, k;
537*0Sstevel@tonic-gate 	char	 block[BUFSIZ];
538*0Sstevel@tonic-gate 
539*0Sstevel@tonic-gate 	for (n = n; n > 0; n--) {
540*0Sstevel@tonic-gate 		if (!oflag || !overlap[n])
541*0Sstevel@tonic-gate 			prange(&de[n].old);
542*0Sstevel@tonic-gate 		else
543*0Sstevel@tonic-gate 			(void) printf("%da\n=======\n", de[n].old.to -1);
544*0Sstevel@tonic-gate 		(void) fseek(fp[2], (long)de[n].new.from, 0);
545*0Sstevel@tonic-gate 		for (k = de[n].new.to-de[n].new.from; k > 0; k -= j) {
546*0Sstevel@tonic-gate 			j = k > BUFSIZ?BUFSIZ:k;
547*0Sstevel@tonic-gate 			if (fread(block, 1, j, fp[2]) != j)
548*0Sstevel@tonic-gate 				trouble();
549*0Sstevel@tonic-gate 			(void) fwrite(block, 1, j, stdout);
550*0Sstevel@tonic-gate 		}
551*0Sstevel@tonic-gate 		if (!oflag || !overlap[n])
552*0Sstevel@tonic-gate 			(void) printf(".\n");
553*0Sstevel@tonic-gate 		else {
554*0Sstevel@tonic-gate 			(void) printf("%s\n.\n", f3mark);
555*0Sstevel@tonic-gate 			(void) printf("%da\n%s\n.\n", de[n].old.from-1, f1mark);
556*0Sstevel@tonic-gate 		}
557*0Sstevel@tonic-gate 	}
558*0Sstevel@tonic-gate }
559