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diffreg.c (37101B)


      1 /*
      2  * This code contains changes by
      3  * Gunnar Ritter, Freiburg i. Br., Germany, March 2003. All rights reserved.
      4  *
      5  * Conditions 1, 2, and 4 and the no-warranty notice below apply
      6  * to these changes.
      7  *
      8  *
      9  * Copyright (c) 1991
     10  * 	The Regents of the University of California.  All rights reserved.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  * 	This product includes software developed by the University of
     23  * 	California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     39  *
     40  *
     41  * Copyright(C) Caldera International Inc. 2001-2002. All rights reserved.
     42  *
     43  * Redistribution and use in source and binary forms, with or without
     44  * modification, are permitted provided that the following conditions
     45  * are met:
     46  *   Redistributions of source code and documentation must retain the
     47  *    above copyright notice, this list of conditions and the following
     48  *    disclaimer.
     49  *   Redistributions in binary form must reproduce the above copyright
     50  *    notice, this list of conditions and the following disclaimer in the
     51  *    documentation and/or other materials provided with the distribution.
     52  *   All advertising materials mentioning features or use of this software
     53  *    must display the following acknowledgement:
     54  *      This product includes software developed or owned by Caldera
     55  *      International, Inc.
     56  *   Neither the name of Caldera International, Inc. nor the names of
     57  *    other contributors may be used to endorse or promote products
     58  *    derived from this software without specific prior written permission.
     59  *
     60  * USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
     61  * INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
     62  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     63  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     64  * ARE DISCLAIMED. IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE
     65  * LIABLE FOR ANY DIRECT, INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR
     66  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     67  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
     68  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     69  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
     70  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
     71  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     72  */
     73 
     74 /*	Sccsid @(#)diffreg.c	1.30 (gritter) 3/15/07>	*/
     75 /*	from 4.3BSD diffreg.c 4.16 3/29/86	*/
     76 
     77 #include "diff.h"
     78 #include <sys/types.h>
     79 #include <sys/stat.h>
     80 #include <fcntl.h>
     81 #include <unistd.h>
     82 #include <time.h>
     83 #include <signal.h>
     84 #include "sigset.h"
     85 #include <wchar.h>
     86 #include <wctype.h>
     87 #include <inttypes.h>
     88 #include "mbtowi.h"
     89 /*
     90  * diff - compare two files.
     91  */
     92 
     93 /*
     94  *	Uses an algorithm due to Harold Stone, which finds
     95  *	a pair of longest identical subsequences in the two
     96  *	files.
     97  *
     98  *	The major goal is to generate the match vector J.
     99  *	J[i] is the index of the line in file1 corresponding
    100  *	to line i file0. J[i] = 0 if there is no
    101  *	such line in file1.
    102  *
    103  *	Lines are hashed so as to work in core. All potential
    104  *	matches are located by sorting the lines of each file
    105  *	on the hash (called ``value''). In particular, this
    106  *	collects the equivalence classes in file1 together.
    107  *	Subroutine equiv replaces the value of each line in
    108  *	file0 by the index of the first element of its 
    109  *	matching equivalence in (the reordered) file1.
    110  *	To save space equiv squeezes file1 into a single
    111  *	array member in which the equivalence classes
    112  *	are simply concatenated, except that their first
    113  *	members are flagged by changing sign.
    114  *
    115  *	Next the indices that point into member are unsorted into
    116  *	array class according to the original order of file0.
    117  *
    118  *	The cleverness lies in routine stone. This marches
    119  *	through the lines of file0, developing a vector klist
    120  *	of "k-candidates". At step i a k-candidate is a matched
    121  *	pair of lines x,y (x in file0 y in file1) such that
    122  *	there is a common subsequence of length k
    123  *	between the first i lines of file0 and the first y 
    124  *	lines of file1, but there is no such subsequence for
    125  *	any smaller y. x is the earliest possible mate to y
    126  *	that occurs in such a subsequence.
    127  *
    128  *	Whenever any of the members of the equivalence class of
    129  *	lines in file1 matable to a line in file0 has serial number 
    130  *	less than the y of some k-candidate, that k-candidate 
    131  *	with the smallest such y is replaced. The new 
    132  *	k-candidate is chained (via pred) to the current
    133  *	k-1 candidate so that the actual subsequence can
    134  *	be recovered. When a member has serial number greater
    135  *	that the y of all k-candidates, the klist is extended.
    136  *	At the end, the longest subsequence is pulled out
    137  *	and placed in the array J by unravel
    138  *
    139  *	With J in hand, the matches there recorded are
    140  *	check'ed against reality to assure that no spurious
    141  *	matches have crept in due to hashing. If they have,
    142  *	they are broken, and "jackpot" is recorded--a harmless
    143  *	matter except that a true match for a spuriously
    144  *	mated line may now be unnecessarily reported as a change.
    145  *
    146  *	Much of the complexity of the program comes simply
    147  *	from trying to minimize core utilization and
    148  *	maximize the range of doable problems by dynamically
    149  *	allocating what is needed and reusing what is not.
    150  *	The core requirements for problems larger than somewhat
    151  *	are (in words) 2*length(file0) + length(file1) +
    152  *	3*(number of k-candidates installed),  typically about
    153  *	6n words for files of length n. 
    154  */
    155 
    156 #define	prints(s)	fputs(s,stdout)
    157 
    158 static FILE	*input[2];
    159 static char	mbuf[2][MB_LEN_MAX+1];
    160 static char	*mcur[2];
    161 static char	*mend[2];
    162 static int	incompl[2];
    163 
    164 struct cand {
    165 	long	x;
    166 	long	y;
    167 	long	pred;
    168 } cand;
    169 static struct line {
    170 	long	serial;
    171 	long	value;
    172 } *file[2], line;
    173 static long	len[2];
    174 static struct	line *sfile[2];/*shortened by pruning common prefix and suffix*/
    175 static long	slen[2];
    176 static long	pref, suff;	/* length of prefix and suffix */
    177 static long	*class;		/* will be overlaid on file[0] */
    178 static long	*member;	/* will be overlaid on file[1] */
    179 static long	*klist;		/* will be overlaid on file[0] after class */
    180 static struct	cand *clist;	/* merely a free storage pot for candidates */
    181 static long	clen = 0;
    182 static long	*J;		/* will be overlaid on class */
    183 static off_t	*ixold;		/* will be overlaid on klist */
    184 static off_t	*ixnew;		/* will be overlaid on file[1] */
    185 static int	(*chrtran)(int);/* translation for case-folding */
    186 static long	pstart;		/* start of last search for -p */
    187 static long	plast;		/* match of last search for -p */
    188 static long	*saveJ;		/* saved J for -p */
    189 
    190 /* chrtran points to one of 3 translation functions:
    191  *	cup2low if folding upper to lower case
    192  *	clow2low if not folding case
    193  *	wlow2low if not folding case and MB_CUR_MAX > 1
    194  */
    195 static int
    196 clow2low(int c)
    197 {
    198 	return c;
    199 }
    200 
    201 static int
    202 cup2low(int c)
    203 {
    204 	return tolower(c);
    205 }
    206 
    207 static int
    208 wup2low(int c)
    209 {
    210 	return c & ~(wchar_t)0177 ? towlower(c) : tolower(c);
    211 }
    212 
    213 static char	*copytemp(char **, const char *);
    214 #undef	splice
    215 #define	splice	xxsplice
    216 static char	*splice(const char *, char *);
    217 static void	prepare(int);
    218 static void	prune(void);
    219 static void	equiv(struct line *, long, struct line *, long, long *);
    220 static long	stone(long *, long, long *, long *);
    221 static long	newcand(long, long, long);
    222 static long	search(long *, long, long);
    223 static void	unravel(long);
    224 static void	check_sb(void);
    225 static void	check_mb(void);
    226 static void	sort(struct line *, long);
    227 static void	unsort(struct line *, long, long *);
    228 static long	skipline(int);
    229 static long	wskipline(int);
    230 static void	output(void);
    231 static void	change(long, long, long, long);
    232 static void	range(long, long, const char *);
    233 static void	fetch(off_t *, long, long, FILE *, const char *, int);
    234 static int	readhash(int);
    235 static int	asciifile(FILE *);
    236 static void	dump_context_vec(void);
    237 static void	sdone(int);
    238 static char	*wcget(int, wint_t *, int *);
    239 static void	missnl(int);
    240 static void	pdump(long);
    241 
    242 #define	notseekable(m)	(((m)&S_IFMT) != S_IFREG && ((m)&S_IFMT) != S_IFBLK)
    243 
    244 void
    245 diffreg(void)
    246 {
    247 	register long i, j;
    248 	char buf1[BUFSIZ], buf2[BUFSIZ];
    249 
    250 	if (hflag) {
    251 		diffargv[0] = "diffh";
    252 		execvp(diffh, diffargv);
    253 		if (sysv3)
    254 			fprintf(stderr, "%s: cannot find diffh\n", progname);
    255 		else
    256 			fprintf(stderr, "%s: %s: %s\n", progname, diffh,
    257 					strerror(errno));
    258 		done();
    259 	}
    260 	chrtran = (iflag? mb_cur_max>1 ? wup2low : cup2low : clow2low);
    261 	if ((stb1.st_mode & S_IFMT) == S_IFDIR) {
    262 		file1 = splice(file1, file2);
    263 		if (stat(file1, &stb1) < 0) {
    264 			if (sysv3)
    265 				stb1.st_mode = S_IFREG;
    266 			else {
    267 				fprintf(stderr, "%s: %s: %s\n", progname, file1,
    268 						strerror(errno));
    269 				done();
    270 			}
    271 		}
    272 	} else if ((stb2.st_mode & S_IFMT) == S_IFDIR) {
    273 		file2 = splice(file2, file1);
    274 		if (stat(file2, &stb2) < 0) {
    275 			if (sysv3)
    276 				stb2.st_mode = S_IFREG;
    277 			else {
    278 				fprintf(stderr, "%s: %s: %s\n", progname, file2,
    279 						strerror(errno));
    280 				done();
    281 			}
    282 		}
    283 	}
    284 	if (!strcmp(file1, "-") || (notseekable(stb1.st_mode) &&
    285 				strcmp(file1, "/dev/null"))) {
    286 		if (!strcmp(file2, "-")) {
    287 			fprintf(stderr, "%s: can't specify - -\n", progname);
    288 			done();
    289 		}
    290 		file1 = copytemp(&tempfile1, file1);
    291 		if (stat(file1, &stb1) < 0) {
    292 			fprintf(stderr, "%s: %s: %s\n", progname, file1,
    293 					strerror(errno));
    294 			done();
    295 		}
    296 	} else if (!strcmp(file2, "-") || (notseekable(stb2.st_mode) &&
    297 				strcmp(file2, "/dev/null"))) {
    298 		file2 = copytemp(&tempfile2, file2);
    299 		if (stat(file2, &stb2) < 0) {
    300 			fprintf(stderr, "%s: %s: %s\n", progname, file2,
    301 					strerror(errno));
    302 			done();
    303 		}
    304 	}
    305 	if ((input[0] = fopen(file1, "r")) == NULL) {
    306 		if (sysv3)
    307 			fprintf(stderr, "%s: cannot open %s\n",
    308 					progname, file1);
    309 		else
    310 			fprintf(stderr, "%s: %s: %s\n", progname, file1,
    311 					strerror(errno));
    312 		done();
    313 	}
    314 	mcur[0] = mend[0] = NULL;
    315 	if ((input[1] = fopen(file2, "r")) == NULL) {
    316 		if (sysv3)
    317 			fprintf(stderr, "%s: cannot open %s\n",
    318 					progname, file2);
    319 		else
    320 			fprintf(stderr, "%s: %s: %s\n", progname, file2,
    321 					strerror(errno));
    322 		fclose(input[0]);
    323 		done();
    324 	}
    325 	mcur[1] = mend[1] = NULL;
    326 	if (stb1.st_size != stb2.st_size)
    327 		goto notsame;
    328 	for (;;) {
    329 		i = fread(buf1, 1, BUFSIZ, input[0]);
    330 		j = fread(buf2, 1, BUFSIZ, input[1]);
    331 		if (i < 0 || j < 0 || i != j)
    332 			goto notsame;
    333 		if (i == 0 && j == 0) {
    334 			fclose(input[0]);
    335 			fclose(input[1]);
    336 			status = 0;		/* files don't differ */
    337 			goto same;
    338 		}
    339 		for (j = 0; j < i; j++)
    340 			if (buf1[j] != buf2[j])
    341 				goto notsame;
    342 	}
    343 notsame:
    344 	/*
    345 	 *	Files certainly differ at this point; set status accordingly
    346 	 */
    347 	status = 1;
    348 	if (!aflag && (!asciifile(input[0]) || !asciifile(input[1]))) {
    349 		printf("Binary files %s and %s differ\n", file1, file2);
    350 		fclose(input[0]);
    351 		fclose(input[1]);
    352 		done();
    353 	}
    354 	prepare(0);
    355 	prepare(1);
    356 	fclose(input[0]);
    357 	fclose(input[1]);
    358 	prune();
    359 	sort(sfile[0],slen[0]);
    360 	sort(sfile[1],slen[1]);
    361 
    362 	member = (long *)file[1];
    363 	equiv(sfile[0], slen[0], sfile[1], slen[1], member);
    364 	member = ralloc(member,(slen[1]+2)*sizeof(*member));
    365 
    366 	class = (long *)file[0];
    367 	unsort(sfile[0], slen[0], class);
    368 	class = ralloc(class,(slen[0]+2)*sizeof(*class));
    369 
    370 	klist = talloc((slen[0]+2)*sizeof(*klist));
    371 	clist = talloc(sizeof(cand));
    372 	i = stone(class, slen[0], member, klist);
    373 	tfree(member);
    374 	tfree(class);
    375 
    376 	J = talloc((len[0]+2)*sizeof(*J));
    377 	unravel(klist[i]);
    378 	tfree(clist);
    379 	tfree(klist);
    380 
    381 	ixold = talloc((len[0]+2)*sizeof(*ixold));
    382 	ixnew = talloc((len[1]+2)*sizeof(*ixnew));
    383 	if (mb_cur_max > 1)
    384 		check_mb();
    385 	else
    386 		check_sb();
    387 	pstart = plast = 0;
    388 	output();
    389 	status = anychange;
    390 same:
    391 	if (opt == D_CONTEXT && anychange == 0)
    392 		printf("No differences encountered\n");
    393 	done();
    394 }
    395 
    396 static char *
    397 copytemp(char **tf, const char *fn)
    398 {
    399 	const char	templ[] = "/tmp/dXXXXXX";
    400 	char buf[BUFSIZ];
    401 	register int i, f, sfd;
    402 
    403 	if (*tf) {
    404 		unlink(*tf);
    405 		strcpy(*tf, templ);
    406 	} else {
    407 		sigset(SIGHUP,sdone);
    408 		sigset(SIGINT,sdone);
    409 		sigset(SIGPIPE,sdone);
    410 		sigset(SIGTERM,sdone);
    411 		*tf = strdup(templ);
    412 	}
    413 	f = mkstemp(*tf);
    414 	if (f < 0) {
    415 		fprintf(stderr, "%s: cannot create %s\n", progname, *tf);
    416 		done();
    417 	}
    418 	if (strcmp(fn, "-")) {
    419 		if ((sfd = open(fn, O_RDONLY)) < 0) {
    420 			fprintf(stderr, "%s: %s: %s\n", progname, fn,
    421 					strerror(errno));
    422 			done();
    423 		}
    424 	} else
    425 		sfd = 0;
    426 	while ((i = read(sfd,buf,BUFSIZ)) > 0)
    427 		if (write(f,buf,i) != i) {
    428 			fprintf(stderr, "%s: write failed %s\n", progname, *tf);
    429 			done();
    430 		}
    431 	close(f);
    432 	if (sfd > 0)
    433 		close(sfd);
    434 	return (*tf);
    435 }
    436 
    437 static char *
    438 splice(const char *dir, char *file)
    439 {
    440 	const char *tail;
    441 	char *buf;
    442 
    443 	if (!strcmp(file, "-")) {
    444 		fprintf(stderr,
    445 			"%s: can't specify - with other arg directory\n",
    446 			progname);
    447 		done();
    448 	}
    449 	tail = basename(file);
    450 	buf = talloc(strlen(dir) + strlen(tail) + 2);
    451 	sprintf(buf, "%s/%s", dir, tail);
    452 	return (buf);
    453 }
    454 
    455 static void
    456 prepare(int i)
    457 {
    458 	register struct line *p;
    459 	register long j;
    460 	register long h;
    461 
    462 	fseeko(input[i], 0, SEEK_SET);
    463 	mcur[i] = mend[i] = NULL;
    464 	p = talloc(3*sizeof(line));
    465 	for(j=0; h=readhash(i);) {
    466 		p = ralloc(p,(++j+3)*sizeof(line));
    467 		p[j].value = h;
    468 	}
    469 	len[i] = j;
    470 	file[i] = p;
    471 }
    472 
    473 static void
    474 prune(void)
    475 {
    476 	register long i;
    477 	register int j;
    478 	for(pref=0;pref<len[0]&&pref<len[1]&&
    479 		file[0][pref+1].value==file[1][pref+1].value;
    480 		pref++ ) ;
    481 	for(suff=0;suff<len[0]-pref&&suff<len[1]-pref&&
    482 		file[0][len[0]-suff].value==file[1][len[1]-suff].value;
    483 		suff++) ;
    484 	for(j=0;j<2;j++) {
    485 		sfile[j] = file[j]+pref;
    486 		slen[j] = len[j]-pref-suff;
    487 		for(i=0;i<=slen[j];i++)
    488 			sfile[j][i].serial = i;
    489 	}
    490 }
    491 
    492 static void
    493 equiv(struct line *a,long n,struct line *b,long m,long *c)
    494 {
    495 	register long i, j;
    496 	i = j = 1;
    497 	while(i<=n && j<=m) {
    498 		if(a[i].value <b[j].value)
    499 			a[i++].value = 0;
    500 		else if(a[i].value == b[j].value)
    501 			a[i++].value = j;
    502 		else
    503 			j++;
    504 	}
    505 	while(i <= n)
    506 		a[i++].value = 0;
    507 	b[m+1].value = 0;
    508 	j = 0;
    509 	while(++j <= m) {
    510 		c[j] = -b[j].serial;
    511 		while(b[j+1].value == b[j].value) {
    512 			j++;
    513 			c[j] = b[j].serial;
    514 		}
    515 	}
    516 	c[j] = -1;
    517 }
    518 
    519 static long
    520 stone(long *a,long n,long *b,register long *c)
    521 {
    522 	register long i, k,y;
    523 	long j, l;
    524 	long oldc, tc;
    525 	long oldl;
    526 	k = 0;
    527 	c[0] = newcand(0,0,0);
    528 	for(i=1; i<=n; i++) {
    529 		j = a[i];
    530 		if(j==0)
    531 			continue;
    532 		y = -b[j];
    533 		oldl = 0;
    534 		oldc = c[0];
    535 		do {
    536 			if(y <= clist[oldc].y)
    537 				continue;
    538 			l = search(c, k, y);
    539 			if(l!=oldl+1)
    540 				oldc = c[l-1];
    541 			if(l<=k) {
    542 				if(clist[c[l]].y <= y)
    543 					continue;
    544 				tc = c[l];
    545 				c[l] = newcand(i,y,oldc);
    546 				oldc = tc;
    547 				oldl = l;
    548 			} else {
    549 				c[l] = newcand(i,y,oldc);
    550 				k++;
    551 				break;
    552 			}
    553 		} while((y=b[++j]) > 0);
    554 	}
    555 	return(k);
    556 }
    557 
    558 static long
    559 newcand(long x,long y,long pred)
    560 {
    561 	register struct cand *q;
    562 	clist = ralloc(clist,++clen*sizeof(cand));
    563 	q = clist + clen -1;
    564 	q->x = x;
    565 	q->y = y;
    566 	q->pred = pred;
    567 	return(clen-1);
    568 }
    569 
    570 static long
    571 search(long *c, long k, long y)
    572 {
    573 	register long i, j, l;
    574 	long t;
    575 	if(clist[c[k]].y<y)	/*quick look for typical case*/
    576 		return(k+1);
    577 	i = 0;
    578 	j = k+1;
    579 	while (1) {
    580 		l = i + j;
    581 		if ((l >>= 1) <= i) 
    582 			break;
    583 		t = clist[c[l]].y;
    584 		if(t > y)
    585 			j = l;
    586 		else if(t < y)
    587 			i = l;
    588 		else
    589 			return(l);
    590 	}
    591 	return(l+1);
    592 }
    593 
    594 static void
    595 unravel(long p)
    596 {
    597 	register long i;
    598 	register struct cand *q;
    599 	for(i=0; i<=len[0]; i++)
    600 		J[i] =	i<=pref ? i:
    601 			i>len[0]-suff ? i+len[1]-len[0]:
    602 			0;
    603 	for(q=clist+p;q->y!=0;q=clist+q->pred)
    604 		J[q->x+pref] = q->y+pref;
    605 }
    606 
    607 /* check does double duty:
    608 1.  ferret out any fortuitous correspondences due
    609 to confounding by hashing (which result in "jackpot")
    610 2.  collect random access indexes to the two files */
    611 
    612 static void
    613 check_sb(void)
    614 {
    615 	register long i, j;
    616 	long jackpot;
    617 	off_t ctold, ctnew;
    618 	register int c,d;
    619 
    620 	if ((input[0] = fopen(file1,"r")) == NULL) {
    621 		perror(file1);
    622 		done();
    623 	}
    624 	if ((input[1] = fopen(file2,"r")) == NULL) {
    625 		perror(file2);
    626 		fclose(input[0]);
    627 		done();
    628 	}
    629 	j = 1;
    630 	ixold[0] = ixnew[0] = 0;
    631 	jackpot = 0;
    632 	ctold = ctnew = 0;
    633 	for(i=1;i<=len[0];i++) {
    634 		if(J[i]==0) {
    635 			ixold[i] = ctold += skipline(0);
    636 			continue;
    637 		}
    638 		while(j<J[i]) {
    639 			ixnew[j] = ctnew += skipline(1);
    640 			j++;
    641 		}
    642 		if(bflag || wflag || iflag) {
    643 			for(;;) {
    644 				c = getc(input[0]);
    645 				d = getc(input[1]);
    646 				ctold++;
    647 				ctnew++;
    648 				if(bflag && isspace(c) && isspace(d)) {
    649 					do {
    650 						if(c=='\n')
    651 							break;
    652 						ctold++;
    653 					} while(isspace(c=getc(input[0])));
    654 					do {
    655 						if(d=='\n')
    656 							break;
    657 						ctnew++;
    658 					} while(isspace(d=getc(input[1])));
    659 				} else if ( wflag ) {
    660 					while( isspace(c) && c!='\n' ) {
    661 						c=getc(input[0]);
    662 						ctold++;
    663 					}
    664 					while( isspace(d) && d!='\n' ) {
    665 						d=getc(input[1]);
    666 						ctnew++;
    667 					}
    668 				}
    669 				if(chrtran(c) != chrtran(d)) {
    670 					jackpot++;
    671 					J[i] = 0;
    672 					if(c!='\n')
    673 						ctold += skipline(0);
    674 					if(d!='\n')
    675 						ctnew += skipline(1);
    676 					break;
    677 				}
    678 				if(c=='\n' || c==EOF)
    679 					break;
    680 			}
    681 		} else {
    682 			for(;;) {
    683 				ctold++;
    684 				ctnew++;
    685 				if((c=getc(input[0])) != (d=getc(input[1]))) {
    686 					/* jackpot++; */
    687 					J[i] = 0;
    688 					if(c!='\n')
    689 						ctold += skipline(0);
    690 					if(d!='\n')
    691 						ctnew += skipline(1);
    692 					break;
    693 				}
    694 				if(c=='\n' || c==EOF)
    695 					break;
    696 			}
    697 		}
    698 		ixold[i] = ctold;
    699 		ixnew[j] = ctnew;
    700 		j++;
    701 	}
    702 	for(;j<=len[1];j++) {
    703 		ixnew[j] = ctnew += skipline(1);
    704 	}
    705 	fclose(input[0]);
    706 	fclose(input[1]);
    707 /*
    708 	if(jackpot)
    709 		fprintf(stderr, "jackpot\n");
    710 */
    711 }
    712 
    713 static void
    714 check_mb(void)
    715 {
    716 	register long i, j;
    717 	long jackpot;
    718 	off_t ctold, ctnew;
    719 	wint_t	wc, wd;
    720 	int	nc, nd;
    721 	char	*cc, *cd;
    722 
    723 	if ((input[0] = fopen(file1,"r")) == NULL) {
    724 		perror(file1);
    725 		done();
    726 	}
    727 	mcur[0] = mend[0] = NULL;
    728 	if ((input[1] = fopen(file2,"r")) == NULL) {
    729 		perror(file2);
    730 		fclose(input[0]);
    731 		done();
    732 	}
    733 	mcur[1] = mend[1] = NULL;
    734 	j = 1;
    735 	ixold[0] = ixnew[0] = 0;
    736 	jackpot = 0;
    737 	ctold = ctnew = 0;
    738 	for(i=1;i<=len[0];i++) {
    739 		if(J[i]==0) {
    740 			ixold[i] = ctold += wskipline(0);
    741 			continue;
    742 		}
    743 		while(j<J[i]) {
    744 			ixnew[j] = ctnew += wskipline(1);
    745 			j++;
    746 		}
    747 		if(bflag || wflag || iflag) {
    748 			for(;;) {
    749 				cc = wcget(0, &wc, &nc);
    750 				cd = wcget(1, &wd, &nd);
    751 				if(bflag && iswspace(wc) && iswspace(wd)) {
    752 					do {
    753 						if(wc=='\n')
    754 							break;
    755 						ctold += nc;
    756 					} while(cc = wcget(0, &wc, &nc),
    757 							iswspace(wc));
    758 					do {
    759 						if(wd=='\n')
    760 							break;
    761 						ctnew += nd;
    762 					} while(cd = wcget(1, &wd, &nd),
    763 							iswspace(wd));
    764 					ctold += nc;
    765 					ctnew += nd;
    766 				} else if ( wflag ) {
    767 					ctold += nc;
    768 					ctnew += nd;
    769 					while( iswspace(wc) && wc!='\n' && cc) {
    770 						cc = wcget(0, &wc, &nc);
    771 						ctold += nc;
    772 					}
    773 					while( iswspace(wd) && wd!='\n' && cd) {
    774 						cd = wcget(1, &wd, &nd);
    775 						ctnew += nd;
    776 					}
    777 				} else {
    778 					ctold += nc;
    779 					ctnew += nd;
    780 				}
    781 				if(chrtran(wc) != chrtran(wd) ||
    782 						wc == WEOF && wd == WEOF &&
    783 						(cc == NULL && cd && *cd ||
    784 						 cc && *cc && cd == NULL ||
    785 						 cc && cd && *cc != *cd)) {
    786 					jackpot++;
    787 					J[i] = 0;
    788 					if(wc!='\n')
    789 						ctold += wskipline(0);
    790 					if(wd!='\n')
    791 						ctnew += wskipline(1);
    792 					break;
    793 				}
    794 				if(wc=='\n' || cc == NULL)
    795 					break;
    796 			}
    797 		} else {
    798 			for(;;) {
    799 				cc = wcget(0, &wc, &nc);
    800 				cd = wcget(1, &wd, &nd);
    801 				ctold += nc;
    802 				ctnew += nd;
    803 				if (wc != wd || wc == WEOF && wd == WEOF &&
    804 						(cc == NULL && cd && *cd ||
    805 						 cc && *cc && cd == NULL ||
    806 						 cc && cd && *cc != *cd)) {
    807 					/* jackpot++; */
    808 					J[i] = 0;
    809 					if(wc!='\n')
    810 						ctold += wskipline(0);
    811 					if(wd!='\n')
    812 						ctnew += wskipline(1);
    813 					break;
    814 				}
    815 				if(wc=='\n' || cc == NULL)
    816 					break;
    817 			}
    818 		}
    819 		ixold[i] = ctold;
    820 		ixnew[j] = ctnew;
    821 		j++;
    822 	}
    823 	for(;j<=len[1];j++) {
    824 		ixnew[j] = ctnew += wskipline(1);
    825 	}
    826 	fclose(input[0]);
    827 	fclose(input[1]);
    828 /*
    829 	if(jackpot)
    830 		fprintf(stderr, "jackpot\n");
    831 */
    832 }
    833 
    834 static void
    835 sort(struct line *a,long n)	/*shellsort CACM #201*/
    836 {
    837 	struct line w;
    838 	register long j,m = 0;
    839 	struct line *ai;
    840 	register struct line *aim;
    841 	long k;
    842 
    843 	if (n == 0)
    844 		return;
    845 	for(j=1;j<=n;j*= 2)
    846 		m = 2*j - 1;
    847 	for(m/=2;m!=0;m/=2) {
    848 		k = n-m;
    849 		for(j=1;j<=k;j++) {
    850 			for(ai = &a[j]; ai > a; ai -= m) {
    851 				aim = &ai[m];
    852 				if(aim < ai)
    853 					break;	/*wraparound*/
    854 				if(aim->value > ai[0].value ||
    855 				   aim->value == ai[0].value &&
    856 				   aim->serial > ai[0].serial)
    857 					break;
    858 				w.value = ai[0].value;
    859 				ai[0].value = aim->value;
    860 				aim->value = w.value;
    861 				w.serial = ai[0].serial;
    862 				ai[0].serial = aim->serial;
    863 				aim->serial = w.serial;
    864 			}
    865 		}
    866 	}
    867 }
    868 
    869 static void
    870 unsort(struct line *f, long l, long *b)
    871 {
    872 	register long *a;
    873 	register long i;
    874 	a = talloc((l+1)*sizeof(*a));
    875 	for(i=1;i<=l;i++)
    876 		a[f[i].serial] = f[i].value;
    877 	for(i=1;i<=l;i++)
    878 		b[i] = a[i];
    879 	tfree(a);
    880 }
    881 
    882 static long
    883 skipline(int f)
    884 {
    885 	register long i;
    886 	register int c;
    887 
    888 	for(i=1;(c=getc(input[f]))!='\n';i++)
    889 		if (c == EOF)
    890 			return(i);
    891 	return(i);
    892 }
    893 
    894 static long
    895 wskipline(int f)
    896 {
    897 	long	i;
    898 	int	n;
    899 	wint_t	wc;
    900 	char	*cp;
    901 
    902 	for (i = 1; cp = wcget(f, &wc, &n), wc != '\n'; i += n)
    903 		if (cp == NULL)
    904 			return (i);
    905 	return (i);
    906 }
    907 
    908 static void
    909 output(void)
    910 {
    911 	long m;
    912 	register long i0, i1, j1;
    913 	long j0;
    914 	if ((input[0] = fopen(file1,"r")) == NULL) {
    915 		perror(file1);
    916 		done();
    917 	}
    918 	if ((input[1] = fopen(file2,"r")) == NULL) {
    919 		perror(file2);
    920 		fclose(input[0]);
    921 		done();
    922 	}
    923 	m = len[0];
    924 	J[0] = 0;
    925 	J[m+1] = len[1]+1;
    926 	if (pflag) {
    927 		saveJ = talloc((len[0]+2)*sizeof(*saveJ));
    928 		memcpy(saveJ, J, (len[0]+2)*sizeof(*saveJ));
    929 	}
    930 	if(opt!=D_EDIT) for(i0=1;i0<=m;i0=i1+1) {
    931 		while(i0<=m&&J[i0]==J[i0-1]+1) i0++;
    932 		j0 = J[i0-1]+1;
    933 		i1 = i0-1;
    934 		while(i1<m&&J[i1+1]==0) i1++;
    935 		j1 = J[i1+1]-1;
    936 		J[i1] = j1;
    937 		change(i0,i1,j0,j1);
    938 	} else for(i0=m;i0>=1;i0=i1-1) {
    939 		while(i0>=1&&J[i0]==J[i0+1]-1&&J[i0]!=0) i0--;
    940 		j0 = J[i0+1]-1;
    941 		i1 = i0+1;
    942 		while(i1>1&&J[i1-1]==0) i1--;
    943 		j1 = J[i1-1]+1;
    944 		J[i1] = j1;
    945 		change(i1,i0,j1,j0);
    946 	}
    947 	if(m==0)
    948 		change(1,0,1,len[1]);
    949 	if (opt==D_IFDEF) {
    950 		for (;;) {
    951 #define	c i0
    952 			c = getc(input[0]);
    953 			if (c == EOF)
    954 				goto end;
    955 			putchar(c);
    956 		}
    957 #undef c
    958 	}
    959 	if (anychange && (opt == D_CONTEXT || opt == D_UNIFIED))
    960 		dump_context_vec();
    961 end:	fclose(input[0]);
    962 	fclose(input[1]);
    963 }
    964 
    965 static int
    966 allblank(off_t *f, long a, long b, FILE *lb)
    967 {
    968 	long	i;
    969 
    970 	if (a > b)
    971 		return 1;
    972 	for (i = a; i <= b; i++)
    973 		if (f[i]-f[i-1] != 1)
    974 			return 0;
    975 	return 1;
    976 }
    977 
    978 /*
    979  * The following struct is used to record change information when
    980  * doing a "context" diff.  (see routine "change" to understand the
    981  * highly mneumonic field names)
    982  */
    983 struct context_vec {
    984 	long	a;	/* start line in old file */
    985 	long	b;	/* end line in old file */
    986 	long	c;	/* start line in new file */
    987 	long	d;	/* end line in new file */
    988 };
    989 
    990 static struct	context_vec	*context_vec_start,
    991 				*context_vec_end,
    992 				*context_vec_ptr;
    993 
    994 #define	MAX_CONTEXT	129
    995 
    996 /* indicate that there is a difference between lines a and b of the from file
    997    to get to lines c to d of the to file.
    998    If a is greater then b then there are no lines in the from file involved
    999    and this means that there were lines appended (beginning at b).
   1000    If c is greater than d then there are lines missing from the to file.
   1001 */
   1002 static void
   1003 change(long a,long b,long c,long d)
   1004 {
   1005 	int ch;
   1006 	struct stat stbuf;
   1007 
   1008 	if (opt != D_IFDEF && a>b && c>d)
   1009 		return;
   1010 	if (Bflag && allblank(ixold,a,b,input[0]) &&
   1011 			allblank(ixnew,c,d,input[1]))
   1012 		return;
   1013 	if (anychange == 0) {
   1014 		anychange = 1;
   1015 		if(opt == D_CONTEXT || opt == D_UNIFIED) {
   1016 			if (opt == D_CONTEXT) {
   1017 				printf("*** %s\t", file1);
   1018 				stat(file1, &stbuf);
   1019 				printf("%s--- %s\t",
   1020 					ctime(&stbuf.st_mtime), file2);
   1021 				stat(file2, &stbuf);
   1022 				printf("%s", ctime(&stbuf.st_mtime));
   1023 			} else {	/* opt == D_UNIFIED */
   1024 				printf("--- %s\t", file1);
   1025 				stat(file1, &stbuf);
   1026 				printf("%s+++ %s\t",
   1027 					ctime(&stbuf.st_mtime), file2);
   1028 				stat(file2, &stbuf);
   1029 				printf("%s", ctime(&stbuf.st_mtime));
   1030 			}
   1031 
   1032 			context_vec_start = talloc(MAX_CONTEXT *
   1033 						   sizeof(*context_vec_start));
   1034 			context_vec_end = context_vec_start + MAX_CONTEXT;
   1035 			context_vec_ptr = context_vec_start - 1;
   1036 		}
   1037 	}
   1038 	if (a <= b && c <= d)
   1039 		ch = 'c';
   1040 	else
   1041 		ch = (a <= b) ? 'd' : 'a';
   1042 	if(opt == D_CONTEXT || opt == D_UNIFIED) {
   1043 		/*
   1044 		 * if this new change is within 'context' lines of
   1045 		 * the previous change, just add it to the change
   1046 		 * record.  If the record is full or if this
   1047 		 * change is more than 'context' lines from the previous
   1048 		 * change, dump the record, reset it & add the new change.
   1049 		 */
   1050 		if ( context_vec_ptr >= context_vec_end-1 ||
   1051 		     ( context_vec_ptr >= context_vec_start &&
   1052 		       a > (context_vec_ptr->b + 2*context) &&
   1053 		       c > (context_vec_ptr->d + 2*context) ) )
   1054 			dump_context_vec();
   1055 
   1056 		context_vec_ptr++;
   1057 		context_vec_ptr->a = a;
   1058 		context_vec_ptr->b = b;
   1059 		context_vec_ptr->c = c;
   1060 		context_vec_ptr->d = d;
   1061 		return;
   1062 	}
   1063 	switch (opt) {
   1064 
   1065 	case D_NORMAL:
   1066 	case D_EDIT:
   1067 		range(a,b,",");
   1068 		putchar(a>b?'a':c>d?'d':'c');
   1069 		if(opt==D_NORMAL)
   1070 			range(c,d,",");
   1071 		putchar('\n');
   1072 		break;
   1073 	case D_REVERSE:
   1074 		putchar(a>b?'a':c>d?'d':'c');
   1075 		range(a,b," ");
   1076 		putchar('\n');
   1077 		break;
   1078         case D_NREVERSE:
   1079                 if (a>b)
   1080                         printf("a%ld %ld\n",b,d-c+1);
   1081                 else {
   1082                         printf("d%ld %ld\n",a,b-a+1);
   1083                         if (!(c>d))
   1084                            /* add changed lines */
   1085                            printf("a%ld %ld\n",b, d-c+1);
   1086                 }
   1087                 break;
   1088 	}
   1089 	if(opt == D_NORMAL || opt == D_IFDEF) {
   1090 		fetch(ixold,a,b,input[0],"< ", 1);
   1091 		if(a<=b&&c<=d && opt == D_NORMAL)
   1092 			prints("---\n");
   1093 	}
   1094 	fetch(ixnew,c,d,input[1],opt==D_NORMAL?"> ":"", 0);
   1095 	if ((opt ==D_EDIT || opt == D_REVERSE) && c<=d)
   1096 		prints(".\n");
   1097 	if (inifdef) {
   1098 		fprintf(stdout, "#endif %s\n", endifname);
   1099 		inifdef = 0;
   1100 	}
   1101 }
   1102 
   1103 static void
   1104 range(long a,long b,const char *separator)
   1105 {
   1106 	printf("%ld", a>b?b:a);
   1107 	if(a<b || opt==D_UNIFIED) {
   1108 		printf("%s%ld", separator, opt==D_UNIFIED ? b-a+1 : b);
   1109 	}
   1110 }
   1111 
   1112 static void
   1113 fetch(off_t *f,long a,long b,FILE *lb,const char *s,int oldfile)
   1114 {
   1115 	register long i, j;
   1116 	register int c;
   1117 	register long col;
   1118 	register long nc;
   1119 	int oneflag = (*ifdef1!='\0') != (*ifdef2!='\0');
   1120 
   1121 	/*
   1122 	 * When doing #ifdef's, copy down to current line
   1123 	 * if this is the first file, so that stuff makes it to output.
   1124 	 */
   1125 	if (opt == D_IFDEF && oldfile){
   1126 		off_t curpos = ftello(lb);
   1127 		/* print through if append (a>b), else to (nb: 0 vs 1 orig) */
   1128 		nc = f[a>b? b : a-1 ] - curpos;
   1129 		for (i = 0; i < nc; i++) {
   1130 			c = getc(lb);
   1131 			if (c == EOF)
   1132 				break;
   1133 			putchar(c);
   1134 		}
   1135 	}
   1136 	if (a > b)
   1137 		return;
   1138 	if (opt == D_IFDEF) {
   1139 		if (inifdef)
   1140 			fprintf(stdout, "#else %s%s\n", oneflag && oldfile==1 ? "!" : "", ifdef2);
   1141 		else {
   1142 			if (oneflag) {
   1143 				/* There was only one ifdef given */
   1144 				endifname = ifdef2;
   1145 				if (oldfile)
   1146 					fprintf(stdout, "#ifndef %s\n", endifname);
   1147 				else
   1148 					fprintf(stdout, "#ifdef %s\n", endifname);
   1149 			}
   1150 			else {
   1151 				endifname = oldfile ? ifdef1 : ifdef2;
   1152 				fprintf(stdout, "#ifdef %s\n", endifname);
   1153 			}
   1154 		}
   1155 		inifdef = 1+oldfile;
   1156 	}
   1157 
   1158 	for(i=a;i<=b;i++) {
   1159 		fseeko(lb,f[i-1],SEEK_SET);
   1160 		nc = f[i]-f[i-1];
   1161 		if (opt != D_IFDEF)
   1162 			prints(s);
   1163 		col = 0;
   1164 		for(j=0;j<nc;j++) {
   1165 			c = getc(lb);
   1166 			if (c == '\t' && tflag)
   1167 				do
   1168 					putchar(' ');
   1169 				while (++col & 7);
   1170 			else if (c == EOF) {
   1171 				if (aflag)
   1172 					printf("\n\\ No newline at "
   1173 							"end of file\n");
   1174 				else
   1175 					putchar('\n');
   1176 				break;
   1177 			} else {
   1178 				putchar(c);
   1179 				col++;
   1180 			}
   1181 		}
   1182 	}
   1183 
   1184 	if (inifdef && !wantelses) {
   1185 		fprintf(stdout, "#endif %s\n", endifname);
   1186 		inifdef = 0;
   1187 	}
   1188 }
   1189 
   1190 #define POW2			/* define only if HALFLONG is 2**n */
   1191 #define HALFLONG 16
   1192 #define low(x)	(x&((1L<<HALFLONG)-1))
   1193 #define high(x)	(x>>HALFLONG)
   1194 
   1195 /*
   1196  * hashing has the effect of
   1197  * arranging line in 7-bit bytes and then
   1198  * summing 1-s complement in 16-bit hunks 
   1199  */
   1200 static int
   1201 readhash(register int f)
   1202 {
   1203 	register int32_t sum;
   1204 	register unsigned shift;
   1205 	register int t;
   1206 	register int space;
   1207 	int	content;
   1208 	wint_t	wt;
   1209 	int	n;
   1210 	char	*cp;
   1211 
   1212 	sum = 1;
   1213 	space = 0;
   1214 	content = 0;
   1215 	if(!bflag && !wflag) {
   1216 		if(iflag) {
   1217 			if (mb_cur_max > 1) {
   1218 				for (shift = 0; cp = wcget(f, &wt, &n),
   1219 						wt != '\n'; shift += 7) {
   1220 					if (cp == NULL) {
   1221 						if (content) {
   1222 							missnl(f);
   1223 							break;
   1224 						}
   1225 						return (0);
   1226 					}
   1227 					content = 1;
   1228 					sum += (int32_t)chrtran(wt) << (shift
   1229 #ifdef POW2
   1230 			    		&= HALFLONG - 1);
   1231 #else
   1232 			    		%= HALFLONG);
   1233 #endif
   1234 				}
   1235 			} else {
   1236 				for(shift=0;(t=getc(input[f]))!='\n';shift+=7) {
   1237 					if(t==EOF) {
   1238 						if (content) {
   1239 							missnl(f);
   1240 							break;
   1241 						}
   1242 						return(0);
   1243 					}
   1244 					content = 1;
   1245 					sum += (int32_t)chrtran(t) << (shift
   1246 #ifdef POW2
   1247 				    	&= HALFLONG - 1);
   1248 #else
   1249 				    	%= HALFLONG);
   1250 #endif
   1251 				}
   1252 			}
   1253 		} else {
   1254 			for(shift=0;(t=getc(input[f]))!='\n';shift+=7) {
   1255 				if(t==EOF) {
   1256 					if (content) {
   1257 						missnl(f);
   1258 						break;
   1259 					}
   1260 					return(0);
   1261 				}
   1262 				content = 1;
   1263 				sum += (int32_t)t << (shift
   1264 #ifdef POW2
   1265 				    &= HALFLONG - 1);
   1266 #else
   1267 				    %= HALFLONG);
   1268 #endif
   1269 			}
   1270 		}
   1271 	} else {
   1272 		if (mb_cur_max > 1) {
   1273 			for(shift=0;;) {
   1274 				if ((cp = wcget(f, &wt, &n)) == NULL) {
   1275 					if (content) {
   1276 						missnl(f);
   1277 						break;
   1278 					}
   1279 					return(0);
   1280 				}
   1281 				content = 1;
   1282 				switch (wt) {
   1283 				default:
   1284 					if (iswspace(wt)) {
   1285 						space++;
   1286 						continue;
   1287 					}
   1288 					if(space && !wflag) {
   1289 						shift += 7;
   1290 						space = 0;
   1291 					}
   1292 					sum += (int32_t)chrtran(wt) << (shift
   1293 #ifdef POW2
   1294 				    	&= HALFLONG - 1);
   1295 #else
   1296 				    	%= HALFLONG);
   1297 #endif
   1298 					shift += 7;
   1299 					continue;
   1300 				case '\n':
   1301 					break;
   1302 				}
   1303 				break;
   1304 			}
   1305 		} else {
   1306 			for(shift=0;;) {
   1307 				switch(t=getc(input[f])) {
   1308 				case EOF:
   1309 					if (content) {
   1310 						missnl(f);
   1311 						break;
   1312 					}
   1313 					return(0);
   1314 				default:
   1315 					content = 1;
   1316 					if (isspace(t)) {
   1317 						space++;
   1318 						continue;
   1319 					}
   1320 					if(space && !wflag) {
   1321 						shift += 7;
   1322 						space = 0;
   1323 					}
   1324 					sum += (int32_t)chrtran(t) << (shift
   1325 #ifdef POW2
   1326 				    	&= HALFLONG - 1);
   1327 #else
   1328 				    	%= HALFLONG);
   1329 #endif
   1330 					shift += 7;
   1331 					continue;
   1332 				case '\n':
   1333 					break;
   1334 				}
   1335 				break;
   1336 			}
   1337 		}
   1338 	}
   1339 	sum = low(sum) + high(sum);
   1340 	return((int16_t)low(sum) + (int16_t)high(sum));
   1341 }
   1342 
   1343 static int
   1344 asciifile(FILE *f)
   1345 {
   1346 	char buf[BUFSIZ];
   1347 	register int cnt;
   1348 	register char *cp;
   1349 
   1350 	fseeko(f, 0, SEEK_SET);
   1351 	cnt = fread(buf, 1, BUFSIZ, f);
   1352 	cp = buf;
   1353 	while (--cnt >= 0)
   1354 		if (*cp++ == '\0')
   1355 			return (0);
   1356 	return (1);
   1357 }
   1358 
   1359 
   1360 /* dump accumulated "context" diff changes */
   1361 static void
   1362 dump_context_vec(void)
   1363 {
   1364 	register long	a, b = 0, c, d = 0;
   1365 	register char	ch;
   1366 	register struct	context_vec *cvp = context_vec_start;
   1367 	register long	lowa, upb, lowc, upd;
   1368 	register int	do_output;
   1369 
   1370 	if ( cvp > context_vec_ptr )
   1371 		return;
   1372 
   1373 	lowa = max(1, cvp->a - context);
   1374 	upb  = min(len[0], context_vec_ptr->b + context);
   1375 	lowc = max(1, cvp->c - context);
   1376 	upd  = min(len[1], context_vec_ptr->d + context);
   1377 
   1378 	if (opt == D_UNIFIED) {
   1379 		printf("@@ -");
   1380 		range(lowa, upb, ",");
   1381 		printf(" +");
   1382 		range(lowc, upd, ",");
   1383 		printf(" @@");
   1384 		if (pflag)
   1385 			pdump(lowa-1);
   1386 		printf("\n");
   1387 
   1388 		while (cvp <= context_vec_ptr) {
   1389 			a = cvp->a; b = cvp->b; c = cvp->c; d = cvp->d;
   1390 
   1391 			if (a <= b && c <= d)
   1392 				ch = 'c';
   1393 			else
   1394 				ch = (a <= b) ? 'd' : 'a';
   1395 
   1396 			switch (ch) {
   1397 			case 'a':
   1398 				fetch(ixold,lowa,b,input[0]," ", 0);
   1399 				fetch(ixnew,c,d,input[1],"+",0);
   1400 				break;
   1401 			case 'c':
   1402 				fetch(ixold,lowa,a-1,input[0]," ", 0);
   1403 				fetch(ixold,a,b,input[0],"-",0);
   1404 				fetch(ixnew,c,d,input[1],"+",0);
   1405 				break;
   1406 			case 'd':
   1407 				fetch(ixold,lowa,a-1,input[0]," ", 0);
   1408 				fetch(ixold,a,b,input[0],"-",0);
   1409 				break;
   1410 			}
   1411 			lowa = b + 1;
   1412 			cvp++;
   1413 		}
   1414 		fetch(ixold, b+1, upb, input[0], " ", 0);
   1415 	}
   1416 
   1417 	if (opt == D_CONTEXT) {
   1418 		printf("***************");
   1419 		if (pflag)
   1420 			pdump(lowa-1);
   1421 		printf("\n*** ");
   1422 		range(lowa,upb,",");
   1423 		printf(" ****\n");
   1424 
   1425 		/*
   1426 		 * output changes to the "old" file.  The first loop suppresses
   1427 		 * output if there were no changes to the "old" file (we'll see
   1428 		 * the "old" lines as context in the "new" list).
   1429 		 */
   1430 		do_output = 0;
   1431 		for ( ; cvp <= context_vec_ptr; cvp++)
   1432 			if (cvp->a <= cvp->b) {
   1433 				cvp = context_vec_start;
   1434 				do_output++;
   1435 				break;
   1436 			}
   1437 	
   1438 		if ( do_output ) {
   1439 			while (cvp <= context_vec_ptr) {
   1440 				a = cvp->a; b = cvp->b; c = cvp->c; d = cvp->d;
   1441 
   1442 				if (a <= b && c <= d)
   1443 					ch = 'c';
   1444 				else
   1445 					ch = (a <= b) ? 'd' : 'a';
   1446 
   1447 				if (ch == 'a')
   1448 					fetch(ixold,lowa,b,input[0],"  ", 0);
   1449 				else {
   1450 					fetch(ixold,lowa,a-1,input[0],"  ", 0);
   1451 					fetch(ixold,a,b,input[0],
   1452 							ch == 'c' ? "! " : "- ",
   1453 							0);
   1454 				}
   1455 				lowa = b + 1;
   1456 				cvp++;
   1457 			}
   1458 			fetch(ixold, b+1, upb, input[0], "  ", 0);
   1459 		}
   1460 
   1461 		/* output changes to the "new" file */
   1462 		printf("--- ");
   1463 		range(lowc,upd,",");
   1464 		printf(" ----\n");
   1465 
   1466 		do_output = 0;
   1467 		for (cvp = context_vec_start; cvp <= context_vec_ptr; cvp++)
   1468 			if (cvp->c <= cvp->d) {
   1469 				cvp = context_vec_start;
   1470 				do_output++;
   1471 				break;
   1472 			}
   1473 	
   1474 		if (do_output) {
   1475 			while (cvp <= context_vec_ptr) {
   1476 				a = cvp->a; b = cvp->b; c = cvp->c; d = cvp->d;
   1477 
   1478 				if (a <= b && c <= d)
   1479 					ch = 'c';
   1480 				else
   1481 					ch = (a <= b) ? 'd' : 'a';
   1482 
   1483 				if (ch == 'd')
   1484 					fetch(ixnew,lowc,d,input[1],"  ", 0);
   1485 				else {
   1486 					fetch(ixnew,lowc,c-1,input[1],"  ", 0);
   1487 					fetch(ixnew,c,d,input[1],
   1488 							ch == 'c' ? "! " : "+ ",
   1489 							0);
   1490 				}
   1491 				lowc = d + 1;
   1492 				cvp++;
   1493 			}
   1494 			fetch(ixnew, d+1, upd, input[1], "  ", 0);
   1495 		}
   1496 	}
   1497 
   1498 	context_vec_ptr = context_vec_start - 1;
   1499 }
   1500 
   1501 /*ARGSUSED*/
   1502 static void
   1503 sdone(int signo)
   1504 {
   1505 	done();
   1506 }
   1507 
   1508 static char *
   1509 wcget(int f, wint_t *wc, int *len)
   1510 {
   1511 	size_t	rest;
   1512 	int	c, i, n;
   1513 
   1514 	i = 0;
   1515 	rest = mend[f] - mcur[f];
   1516 	if (rest && mcur[f] > mbuf[f]) {
   1517 		do
   1518 			mbuf[f][i] = mcur[f][i];
   1519 		while (i++, --rest);
   1520 	} else if (incompl[f]) {
   1521 		incompl[f] = 0;
   1522 		*wc = WEOF;
   1523 		mend[f] = mcur[f] = NULL;
   1524 		return NULL;
   1525 	}
   1526 	if (i == 0) {
   1527 		c = getc(input[f]);
   1528 		if (c == EOF) {
   1529 			*wc = WEOF;
   1530 			mend[f] = mcur[f] = NULL;
   1531 			return NULL;
   1532 		}
   1533 		mbuf[f][i++] = c;
   1534 	}
   1535 	if (mbuf[f][0] & 0200) {
   1536 		while (mbuf[f][i-1] != '\n' && i < mb_cur_max &&
   1537 				incompl[f] == 0) {
   1538 			c = getc(input[f]);
   1539 			if (c != EOF)
   1540 				mbuf[f][i++] = c;
   1541 			else
   1542 				incompl[f] = 1;
   1543 		}
   1544 		n = mbtowi(wc, mbuf[f], i);
   1545 		if (n < 0) {
   1546 			*len = 1;
   1547 			*wc = WEOF;
   1548 		} else if (n == 0) {
   1549 			*len = 1;
   1550 			*wc = '\0';
   1551 		} else
   1552 			*len = n;
   1553 	} else {
   1554 		*wc = mbuf[f][0];
   1555 		*len = n = 1;
   1556 	}
   1557 	mcur[f] = &mbuf[f][*len];
   1558 	mend[f] = &mcur[f][i - *len];
   1559 	return mbuf[f];
   1560 }
   1561 
   1562 static void
   1563 missnl(int f)
   1564 {
   1565 	if (aflag == 0)
   1566 		fprintf(stderr, "Warning: missing newline at end of file %s\n",
   1567 			f == 0 ? file1 : file2);
   1568 }
   1569 
   1570 /*
   1571  * Find and dump the name of the C function with the -p option. The
   1572  * search begins at line sa.
   1573  */
   1574 static void
   1575 pdump(long sa)
   1576 {
   1577 #define	psize	40
   1578 	static char	lbuf[psize*MB_LEN_MAX+1];
   1579 	char	mbuf[MB_LEN_MAX+1];
   1580 	int	c, i, j;
   1581 	wchar_t	wc;
   1582 	long	a = sa;
   1583 
   1584 	while (a-- > pstart) {
   1585 		if (saveJ[a+1] == 0)
   1586 			continue;
   1587 		fseeko(input[0], ixold[a], SEEK_SET);
   1588 		i = 0;
   1589 		do {
   1590 			if ((c=getc(input[0])) == EOF || c == '\n')
   1591 				break;
   1592 			mbuf[i] = c;
   1593 		} while (++i<mb_cur_max);
   1594 		if (mb_cur_max>1) {
   1595 			mbuf[i] = 0;
   1596 			if (((c=mbuf[0])&0200)==0)
   1597 				wc = mbuf[0];
   1598 			else if (mbtowc(&wc, mbuf, i) < 0)
   1599 				continue;
   1600 		}
   1601 		if ((mb_cur_max>1 && mbuf[0]&0200 ? iswalpha(wc):isalpha(c)) ||
   1602 				c == '$' || c == '_') {
   1603 			plast = a+1;
   1604 			for (j = 0; j < i; j++)
   1605 				lbuf[j] = mbuf[j];
   1606 			while (i < sizeof lbuf - 1) {
   1607 				if ((c=getc(input[0])) == EOF || c == '\n')
   1608 					break;
   1609 				lbuf[i++] = c;
   1610 			}
   1611 			for (j=0;j<i&&j<psize;) {
   1612 				if (mb_cur_max==1 || (lbuf[j]&0200) == 0)
   1613 					j++;
   1614 				else {
   1615 					c = mbtowc(NULL, &lbuf[j], i-j);
   1616 					j += c>0 ? c:1;
   1617 				}
   1618 			}
   1619 			lbuf[j] = 0;
   1620 			break;
   1621 		}
   1622 	}
   1623 	pstart = sa;
   1624 	if (plast) {
   1625 		putchar(' ');
   1626 		for (i = 0; lbuf[i]; i++)
   1627 			putchar(lbuf[i] & 0377);
   1628 	}
   1629 }