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      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 (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
     22 /*	  All Rights Reserved  	*/
     23 
     24 
     25 /*
     26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
     27  * Use is subject to license terms.
     28  */
     29 
     30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     31 
     32 #include <stdio.h>
     33 #include <stdlib.h>
     34 #include <unistd.h>
     35 #include <limits.h>
     36 #include <sys/param.h>
     37 #include <errno.h>
     38 #
     39 
     40 /*
     41  * diff3 - 3-way differential file comparison
     42  */
     43 
     44 /*
     45  * diff3 [-ex3EX] d13 d23 f1 f2 f3 [m1 m3]
     46  *
     47  * d13 = diff report on f1 vs f3
     48  * d23 = diff report on f2 vs f3
     49  * f1, f2, f3 the 3 files
     50  * if changes in f1 overlap with changes in f3, m1 and m3 are used
     51  * to mark the overlaps; otherwise, the file names f1 and f3 are used
     52  * (only for options E and X).
     53  */
     54 
     55 struct  range {int from, to; };
     56 	/*
     57 	 * from is first in range of changed lines
     58 	 * to is last+1
     59 	 * from = to = line after point of insertion
     60 	 * for added lines
     61 	 */
     62 struct diff {struct range old, new; };
     63 
     64 #define	NC 4096
     65 /*
     66  * de is used to gather editing scripts,
     67  * that are later spewed out in reverse order.
     68  * its first element must be all zero
     69  * the "new" component of de contains line positions
     70  * or byte positions depending on when you look(!?)
     71  */
     72 static struct diff d13[NC];
     73 static struct diff d23[NC];
     74 
     75 /*
     76  * array overlap indicates which sections in de correspond to
     77  * lines that are different in all three files.
     78  */
     79 
     80 static struct diff de[NC];
     81 static char overlap[NC];
     82 static int  overlapcnt = 0;
     83 
     84 static char line[LINE_MAX+1];
     85 static FILE *fp[3];
     86 /*
     87  *	the number of the last-read line in each file
     88  *	is kept in cline[0-2]
     89  */
     90 static int cline[3];
     91 /*
     92  *	the latest known correspondence between line
     93  *	numbers of the 3 files is stored in last[1-3]
     94  */
     95 static int last[4];
     96 static int eflag;
     97 static int oflag;	/* indicates whether to mark overlaps (-E or -X) */
     98 static int debug  = 0;
     99 /* markers for -E and -X: */
    100 static char f1mark[8+MAXPATHLEN], f3mark[8+MAXPATHLEN];
    101 		/* Need space for "<<<<<<< " or ">>>>>>> " plus filename   */
    102 static int save_err;	/* saves errno */
    103 
    104 static int readin(char *name, struct diff *dd);
    105 static int number(char **lc);
    106 static int digit(int c);
    107 static int getchange(FILE *b);
    108 static int getline(FILE *b);
    109 static void merge(int m1, int m2);
    110 static void separate(char *s);
    111 static void change(int i, struct range *rold, int dup);
    112 static void prange(struct range *rold);
    113 static void keep(int i, struct range *rnew);
    114 static int skip(int i, int from, char *pr);
    115 static int duplicate(struct range *r1, struct range *r2);
    116 static void repos(int nchar);
    117 static void trouble();
    118 static int edit(struct diff *diff, int dup, int j);
    119 static void edscript(int n);
    120 static void usage();
    121 
    122 int
    123 main(int argc, char **argv)
    124 {
    125 	int i, m, n;
    126 	eflag  = 0;
    127 	oflag  = 0;
    128 	if ((argc > 1) && (*argv[1] == '-')) {
    129 		switch (argv[1][1]) {
    130 		case 'e':
    131 			eflag = 3;
    132 			break;
    133 		case '3':
    134 			eflag = 2;
    135 			break;
    136 		case 'x':
    137 			eflag = 1;
    138 			break;
    139 		case 'E':
    140 			eflag = 3;
    141 			oflag = 1;
    142 			break;
    143 		case 'X':
    144 			oflag = eflag = 1;
    145 			break;
    146 		default:
    147 			usage();
    148 			break;
    149 		}
    150 		argv++;
    151 		argc--;
    152 	}
    153 	if (argc < 6)
    154 		usage();
    155 	if (oflag) {
    156 		(void) snprintf(f1mark, sizeof (f1mark), "<<<<<<< %s",
    157 						argc >= 7 ? argv[6] : argv[3]);
    158 		(void) snprintf(f3mark, sizeof (f3mark), ">>>>>>> %s",
    159 						argc >= 8 ? argv[7] : argv[5]);
    160 	}
    161 
    162 	m = readin(argv[1], d13);
    163 	n = readin(argv[2], d23);
    164 	for (i = 0; i <= 2; i++)
    165 		if ((fp[i] = fopen(argv[i+3], "r")) == NULL) {
    166 			save_err = errno;
    167 			(void) fprintf(stderr, "diff3: can't open %s: ",
    168 				argv[i+3]);
    169 			errno = save_err;
    170 			perror("");
    171 			exit(1);
    172 		}
    173 	merge(m, n);
    174 	return (0);
    175 }
    176 
    177 /*
    178  * pick up the line numbers of all changes from
    179  * one change file
    180  * (this puts the numbers in a vector, which is not
    181  * strictly necessary, since the vector is processed
    182  * in one sequential pass. The vector could be optimized
    183  * out of existence)
    184  */
    185 
    186 static int
    187 readin(char *name, struct diff *dd)
    188 {
    189 	int i;
    190 	int a, b, c, d;
    191 	char kind;
    192 	char *p;
    193 	if ((fp[0] = fopen(name, "r")) == NULL) {
    194 		save_err = errno;
    195 		(void) fprintf(stderr, "diff3: can't open %s: ", name);
    196 		errno = save_err;
    197 		perror("");
    198 		exit(1);
    199 	}
    200 	for (i = 0; getchange(fp[0]); i++) {
    201 		if (i >= NC) {
    202 			(void) fprintf(stderr, "diff3: too many changes\n");
    203 			exit(0);
    204 		}
    205 		p = line;
    206 		a = b = number(&p);
    207 		if (*p == ',') {
    208 			p++;
    209 			b = number(&p);
    210 		}
    211 		kind = *p++;
    212 		c = d = number(&p);
    213 		if (*p == ',') {
    214 			p++;
    215 			d = number(&p);
    216 		}
    217 		if (kind == 'a')
    218 			a++;
    219 		if (kind == 'd')
    220 			c++;
    221 		b++;
    222 		d++;
    223 		dd[i].old.from = a;
    224 		dd[i].old.to = b;
    225 		dd[i].new.from = c;
    226 		dd[i].new.to = d;
    227 	}
    228 	dd[i].old.from = dd[i-1].old.to;
    229 	dd[i].new.from = dd[i-1].new.to;
    230 	(void) fclose(fp[0]);
    231 	return (i);
    232 }
    233 
    234 static int
    235 number(char **lc)
    236 {
    237 	int nn;
    238 	nn = 0;
    239 	while (digit(**lc))
    240 		nn = nn*10 + *(*lc)++ - '0';
    241 	return (nn);
    242 }
    243 
    244 static int
    245 digit(int c)
    246 {
    247 	return (c >= '0' && c <= '9');
    248 }
    249 
    250 static int
    251 getchange(FILE *b)
    252 {
    253 	while (getline(b))
    254 		if (digit(line[0]))
    255 			return (1);
    256 	return (0);
    257 }
    258 
    259 static int
    260 getline(FILE *b)
    261 {
    262 	int i, c;
    263 	for (i = 0; i < sizeof (line)-1; i++) {
    264 		c = getc(b);
    265 		if (c == EOF) {
    266 			line[i] = 0;
    267 			return (i);
    268 		}
    269 		line[i] = c;
    270 		if (c == '\n') {
    271 			line[++i] = 0;
    272 			return (i);
    273 		}
    274 	}
    275 	return (0);
    276 }
    277 
    278 static void
    279 merge(int m1, int m2)
    280 {
    281 	struct diff *d1, *d2, *d3;
    282 	int dup;
    283 	int j;
    284 	int t1, t2;
    285 	d1 = d13;
    286 	d2 = d23;
    287 	j = 0;
    288 	for (; (t1 = d1 < d13+m1) | (t2 = d2 < d23+m2); ) {
    289 		if (debug) {
    290 			(void) printf("%d,%d=%d,%d %d,%d=%d,%d\n",
    291 			d1->old.from, d1->old.to,
    292 			d1->new.from, d1->new.to,
    293 			d2->old.from, d2->old.to,
    294 			d2->new.from, d2->new.to);
    295 		}
    296 
    297 		/* first file is different from others */
    298 		if (!t2 || t1 && d1->new.to < d2->new.from) {
    299 			/* stuff peculiar to 1st file */
    300 			if (eflag == 0) {
    301 				separate("1");
    302 				change(1, &d1->old, 0);
    303 				keep(2, &d1->new);
    304 				change(3, &d1->new, 0);
    305 			}
    306 			d1++;
    307 			continue;
    308 		}
    309 
    310 		/* second file is different from others */
    311 		if (!t1 || t2 && d2->new.to < d1->new.from) {
    312 			if (eflag == 0) {
    313 				separate("2");
    314 				keep(1, &d2->new);
    315 				change(2, &d2->old, 0);
    316 				change(3, &d2->new, 0);
    317 			}
    318 			d2++;
    319 			continue;
    320 		}
    321 		/*
    322 		 * merge overlapping changes in first file
    323 		 * this happens after extension see below
    324 		 */
    325 		if (d1+1 < d13+m1 && d1->new.to >= d1[1].new.from) {
    326 			d1[1].old.from = d1->old.from;
    327 			d1[1].new.from = d1->new.from;
    328 			d1++;
    329 			continue;
    330 		}
    331 
    332 		/* merge overlapping changes in second */
    333 		if (d2+1 < d23+m2 && d2->new.to >= d2[1].new.from) {
    334 			d2[1].old.from = d2->old.from;
    335 			d2[1].new.from = d2->new.from;
    336 			d2++;
    337 			continue;
    338 		}
    339 
    340 		/* stuff peculiar to third file or different in all */
    341 		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
    342 			dup = duplicate(&d1->old, &d2->old);
    343 			/*
    344 			 * dup = 0 means all files differ
    345 			 * dup = 1 meands files 1&2 identical
    346 			 */
    347 			if (eflag == 0) {
    348 				separate(dup?"3":"");
    349 				change(1, &d1->old, dup);
    350 				change(2, &d2->old, 0);
    351 				d3 = d1->old.to > d1->old.from ? d1 : d2;
    352 				change(3, &d3->new, 0);
    353 			} else
    354 				j = edit(d1, dup, j);
    355 			d1++;
    356 			d2++;
    357 			continue;
    358 		}
    359 		/*
    360 		 * overlapping changes from file1 & 2
    361 		 * extend changes appropriately to
    362 		 * make them coincide
    363 		 */
    364 		if (d1->new.from < d2->new.from) {
    365 			d2->old.from -= d2->new.from-d1->new.from;
    366 			d2->new.from = d1->new.from;
    367 		} else if (d2->new.from < d1->new.from) {
    368 			d1->old.from -= d1->new.from-d2->new.from;
    369 			d1->new.from = d2->new.from;
    370 		}
    371 
    372 		if (d1->new.to > d2->new.to) {
    373 			d2->old.to += d1->new.to - d2->new.to;
    374 			d2->new.to = d1->new.to;
    375 		} else if (d2->new.to > d1->new.to) {
    376 			d1->old.to += d2->new.to - d1->new.to;
    377 			d1->new.to = d2->new.to;
    378 		}
    379 	}
    380 	if (eflag) {
    381 		edscript(j);
    382 		if (j)
    383 			(void) printf("w\nq\n");
    384 	}
    385 }
    386 
    387 static void
    388 separate(char *s)
    389 {
    390 	(void) printf("====%s\n", s);
    391 }
    392 
    393 /*
    394  * the range of ines rold.from thru rold.to in file i
    395  * is to be changed. it is to be printed only if
    396  * it does not duplicate something to be printed later
    397  */
    398 static void
    399 change(int i, struct range *rold, int dup)
    400 {
    401 	(void) printf("%d:", i);
    402 	last[i] = rold->to;
    403 	prange(rold);
    404 	if (dup)
    405 		return;
    406 	if (debug)
    407 		return;
    408 	i--;
    409 	(void) skip(i, rold->from, (char *)0);
    410 	(void) skip(i, rold->to, "  ");
    411 }
    412 
    413 /*
    414  * print the range of line numbers, rold.from  thru rold.to
    415  * as n1, n2 or n1
    416  */
    417 static void
    418 prange(struct range *rold)
    419 {
    420 	if (rold->to <= rold->from)
    421 		(void) printf("%da\n", rold->from-1);
    422 	else {
    423 		(void) printf("%d", rold->from);
    424 		if (rold->to > rold->from+1)
    425 			(void) printf(",%d", rold->to-1);
    426 		(void) printf("c\n");
    427 	}
    428 }
    429 
    430 /*
    431  * no difference was reported by diff between file 1(or 2)
    432  * and file 3, and an artificial dummy difference (trange)
    433  * must be ginned up to correspond to the change reported
    434  * in the other file
    435  */
    436 static void
    437 keep(int i, struct range *rnew)
    438 {
    439 	int delta;
    440 	struct range trange;
    441 	delta = last[3] - last[i];
    442 	trange.from = rnew->from - delta;
    443 	trange.to = rnew->to - delta;
    444 	change(i, &trange, 1);
    445 }
    446 
    447 /*
    448  * skip to just befor line number from in file i
    449  * if "pr" is nonzero, print all skipped stuff
    450  * with string pr as a prefix
    451  */
    452 static int
    453 skip(int i, int from, char *pr)
    454 {
    455 	int j, n;
    456 	for (n = 0; cline[i] < from-1; n += j) {
    457 		if ((j = getline(fp[i])) == 0)
    458 			trouble();
    459 		if (pr)
    460 			(void) printf("%s%s", pr, line);
    461 		cline[i]++;
    462 	}
    463 	return (n);
    464 }
    465 
    466 /*
    467  * return 1 or 0 according as the old range
    468  * (in file 1) contains exactly the same data
    469  * as the new range (in file 2)
    470  */
    471 static int
    472 duplicate(struct range *r1, struct range *r2)
    473 {
    474 	int c, d;
    475 	int nchar;
    476 	int nline;
    477 	if (r1->to-r1->from != r2->to-r2->from)
    478 		return (0);
    479 	(void) skip(0, r1->from, (char *)0);
    480 	(void) skip(1, r2->from, (char *)0);
    481 	nchar = 0;
    482 	for (nline = 0; nline < r1->to-r1->from; nline++) {
    483 		do {
    484 			c = getc(fp[0]);
    485 			d = getc(fp[1]);
    486 			if (c == -1 || d == -1)
    487 				trouble();
    488 			nchar++;
    489 			if (c != d) {
    490 				repos(nchar);
    491 				return (0);
    492 			}
    493 		} while (c != '\n');
    494 	}
    495 	repos(nchar);
    496 	return (1);
    497 }
    498 
    499 static void
    500 repos(int nchar)
    501 {
    502 	int i;
    503 	for (i = 0; i < 2; i++)
    504 		(void) fseek(fp[i], (long)-nchar, 1);
    505 }
    506 
    507 static void
    508 trouble()
    509 {
    510 	(void) fprintf(stderr, "diff3: logic error\n");
    511 	abort();
    512 }
    513 
    514 /*
    515  * collect an editing script for later regurgitation
    516  */
    517 static int
    518 edit(struct diff *diff, int dup, int j)
    519 {
    520 	if (((dup+1)&eflag) == 0)
    521 		return (j);
    522 	j++;
    523 	overlap[j] = !dup;
    524 	if (!dup) overlapcnt++;
    525 	de[j].old.from = diff->old.from;
    526 	de[j].old.to = diff->old.to;
    527 	de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, (char *)0);
    528 	de[j].new.to = de[j].new.from + skip(2, diff->new.to, (char *)0);
    529 	return (j);
    530 }
    531 
    532 /*		regurgitate */
    533 static void
    534 edscript(int n)
    535 {
    536 	int j, k;
    537 	char	 block[BUFSIZ];
    538 
    539 	for (n = n; n > 0; n--) {
    540 		if (!oflag || !overlap[n])
    541 			prange(&de[n].old);
    542 		else
    543 			(void) printf("%da\n=======\n", de[n].old.to -1);
    544 		(void) fseek(fp[2], (long)de[n].new.from, 0);
    545 		for (k = de[n].new.to-de[n].new.from; k > 0; k -= j) {
    546 			j = k > BUFSIZ?BUFSIZ:k;
    547 			if (fread(block, 1, j, fp[2]) != j)
    548 				trouble();
    549 			(void) fwrite(block, 1, j, stdout);
    550 		}
    551 		if (!oflag || !overlap[n])
    552 			(void) printf(".\n");
    553 		else {
    554 			(void) printf("%s\n.\n", f3mark);
    555 			(void) printf("%da\n%s\n.\n", de[n].old.from-1, f1mark);
    556 		}
    557 	}
    558 }
    559 
    560 static void
    561 usage()
    562 {
    563 	(void) fprintf(stderr,
    564 	    "\tusage: diff3prog [-ex3EX] d13 d23 f1 f2 f3 [m1 m2]\n");
    565 	exit(1);
    566 }
    567