/usr/src/usr.bin/cvs/diff3.c

Bug Summary

File:	src/usr.bin/cvs/diff3.c
Warning:	line 528, column 2 Null pointer passed as 1st argument to memory copy function

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name diff3.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/usr.bin/cvs/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/usr.bin/cvs -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/usr.bin/cvs/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/usr.bin/cvs/diff3.c

1/*	$OpenBSD: diff3.c,v 1.65 2021/04/13 14:20:23 stsp Exp $	*/

3/*
* Copyright (C) Caldera International Inc.  2001-2002.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code and documentation must retain the above
*    copyright notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*	This product includes software developed or owned by Caldera
*	International, Inc.
* 4. Neither the name of Caldera International, Inc. nor the names of other
*    contributors may be used to endorse or promote products derived from
*    this software without specific prior written permission.
*
* USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
* INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE LIABLE FOR ANY DIRECT,
* INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
36/*-
* Copyright (c) 1991, 1993
*	The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*	@(#)diff3.c	8.1 (Berkeley) 6/6/93
*/

67#include <ctype.h>
68#include <errno(*__errno()).h>
69#include <fcntl.h>
70#include <stdio.h>
71#include <stdlib.h>
72#include <string.h>
73#include <unistd.h>

75#include "atomicio.h"
76#include "cvs.h"
77#include "diff.h"

79/* diff3 - 3-way differential file comparison */

81/* diff3 [-ex3EX] d13 d23 f1 f2 f3 [m1 m3]
*
* d13 = diff report on f1 vs f3
* d23 = diff report on f2 vs f3
* f1, f2, f3 the 3 files
* if changes in f1 overlap with changes in f3, m1 and m3 are used
* to mark the overlaps; otherwise, the file names f1 and f3 are used
* (only for options E and X).
*/

91/*
* "from" is first in range of changed lines; "to" is last+1
* from=to=line after point of insertion for added lines.
*/
95struct range {
int from;
int to;
98};

100struct diff {
struct range old;
struct range new;
103};

105static size_t szchanges;

107static struct diff *d13;
108static struct diff *d23;

110/*
* "de" is used to gather editing scripts.  These are later spewed out in
* reverse order.  Its first element must be all zero, the "new" component
* of "de" contains line positions or byte positions depending on when you
* look (!?).  Array overlap indicates which sections in "de" correspond to
* lines that are different in all three files.
*/
117static struct diff *de;
118static char *overlap;
119static int overlapcnt = 0;
120static FILE *fp[3];
121static int cline[3];		/* # of the last-read line in each file (0-2) */

123/*
* the latest known correspondence between line numbers of the 3 files
* is stored in last[1-3];
*/
127static int last[4];
128static int eflag;
129static int oflag;		/* indicates whether to mark overlaps (-E or -X)*/
130static int debug  = 0;
131static char f1mark[PATH_MAX1024], f3mark[PATH_MAX1024];	/* markers for -E and -X */

133static int duplicate(struct range *, struct range *);
134static int edit(struct diff *, int, int);
135static char *getchange(FILE *);
136static char *get_line(FILE *, size_t *);
137static int number(char **);
138static size_t readin(int, struct diff **);
139static int skip(int, int, char *);
140static int edscript(int);
141static int merge(size_t, size_t);
142static void change(int, struct range *, int);
143static void keep(int, struct range *);
144static void prange(struct range *);
145static void repos(int);
146static void separate(const char *);
147static void increase(void);
148static int diff3_internal(int, char **, const char *, const char *);

150int diff3_conflicts = 0;
151RCSNUM *d3rev1 = NULL((void *)0);
152RCSNUM *d3rev2 = NULL((void *)0);

154static int fds[5];

156void
157cvs_merge_file(struct cvs_file *cf, int verbose)
158{
int i, argc;
char *data, *patch;
char *argv[5], r1[CVS_REV_BUFSZ32], r2[CVS_REV_BUFSZ32];
char *dp13, *dp23, *path1, *path2, *path3;
BUF *b1, *d1, *d2, *diffb;
size_t dlen, plen;
struct rcs_line *lp;
struct rcs_lines *dlines, *plines;

overlapcnt = 0;
b1 = d1 = d2 = diffb = NULL((void *)0);

rcsnum_tostr(d3rev1, r1, sizeof(r1));
rcsnum_tostr(d3rev2, r2, sizeof(r2));

b1 = buf_load_fd(cf->fd);
d1 = buf_alloc(128);
d2 = buf_alloc(128);
diffb = buf_alloc(128);

(void)xasprintf(&path1, "%s/diff1.XXXXXXXXXX", cvs_tmpdir);
(void)xasprintf(&path2, "%s/diff2.XXXXXXXXXX", cvs_tmpdir);
(void)xasprintf(&path3, "%s/diff3.XXXXXXXXXX", cvs_tmpdir);

fds[2] = buf_write_stmp(b1, path1, NULL((void *)0));
if (verbose == 1)
1
Assuming 'verbose' is not equal to 1→
2
←
Taking false branch→
cvs_printf("Retrieving revision %s\n", r1);
fds[3] = rcs_rev_write_stmp(cf->file_rcs, d3rev1, path2, 0);
if (verbose2.1
'verbose' is not equal to 1
 == 1)
3
←
Taking false branch→
cvs_printf("Retrieving revision %s\n", r2);
fds[4] = rcs_rev_write_stmp(cf->file_rcs, d3rev2, path3, 0);

diffreg(path1, path3, fds[2], fds[4], d1, D_FORCEASCII0x01);
diffreg(path2, path3, fds[3], fds[4], d2, D_FORCEASCII0x01);

(void)xasprintf(&dp13, "%s/d13.XXXXXXXXXX", cvs_tmpdir);
fds[0] = buf_write_stmp(d1, dp13, NULL((void *)0));
buf_free(d1);

(void)xasprintf(&dp23, "%s/d23.XXXXXXXXXX", cvs_tmpdir);
fds[1] = buf_write_stmp(d2, dp23, NULL((void *)0));
buf_free(d2);

argc = 0;
diffbuf = diffb;
argv[argc++] = dp13;
argv[argc++] = dp23;
argv[argc++] = path1;
argv[argc++] = path2;
argv[argc++] = path3;

if (lseek(fds[2], 0, SEEK_SET0) == -1)
4
←
Assuming the condition is false→
5
←
Taking false branch→
fatal("cvs_merge_file: lseek fds[2]: %s", strerror(errno(*__errno())));
if (lseek(fds[3], 0, SEEK_SET0) == -1)
6
←
Assuming the condition is false→
7
←
Taking false branch→
fatal("cvs_merge_file: lseek fds[3]: %s", strerror(errno(*__errno())));
if (lseek(fds[4], 0, SEEK_SET0) == -1)
8
←
Assuming the condition is false→
9
←
Taking false branch→
fatal("cvs_merge_file: lseek fds[4]: %s", strerror(errno(*__errno())));

diff3_conflicts = diff3_internal(argc, argv, cf->file_path, r2);
10
←
Calling 'diff3_internal'→
if (diff3_conflicts < 0)
fatal("cvs_merge_file: merging failed for an unknown reason");

plen = buf_len(diffb);
patch = buf_release(diffb);
dlen = buf_len(b1);
data = buf_release(b1);

if (verbose == 1)
cvs_printf("Merging differences between %s and %s into `%s'\n",
    r1, r2, cf->file_path);

dlines = cvs_splitlines(data, dlen);
plines = cvs_splitlines(patch, plen);

ed_patch_lines(dlines, plines);
cvs_freelines(plines);

if (verbose == 1 && diff3_conflicts != 0) {
cvs_log(LP_ERR1, "%d conflict%s found during merge, "
    "please correct.", diff3_conflicts,
    (diff3_conflicts > 1) ? "s" : "");
}

(void)close(cf->fd);
cf->fd = open(cf->file_path, O_CREAT0x0200 | O_RDWR0x0002 | O_TRUNC0x0400, 0644);
if (cf->fd == -1) {
fatal("cvs_merge_file: failed to reopen fd for writing: %s",
    strerror(errno(*__errno())));
}

TAILQ_FOREACH(lp, &(dlines->l_lines), l_list)for((lp) = ((&(dlines->l_lines))->tqh_first); (lp) !=
 ((void *)0); (lp) = ((lp)->l_list.tqe_next)) {
if (lp->l_line == NULL((void *)0))
	continue;

if (atomicio(vwrite(ssize_t (*)(int, void *, size_t))write, cf->fd, lp->l_line, lp->l_len) !=
    lp->l_len)
	fatal("cvs_merge_file: %s", strerror(errno(*__errno())));
}

cvs_freelines(dlines);

free(data);
free(patch);

for (i = 0; i < 3; i++)
fclose(fp[i]);

worklist_run(&temp_files, worklist_unlink);

free(path1);
free(path2);
free(path3);
free(dp13);
free(dp23);
273}

275static int
276diff3_internal(int argc, char **argv, const char *fmark, const char *rmark)
277{
size_t m, n;
int i;

eflag = 3;
oflag = 1;

if (argc10.1
'argc' is >= 5
 < 5)
11
←
Taking false branch→
return (-1);

(void)xsnprintf(f1mark, sizeof(f1mark), "<<<<<<< %s", fmark);
(void)xsnprintf(f3mark, sizeof(f3mark), ">>>>>>> %s", rmark);

szchanges = 0;
memset(last, 0, sizeof(last));
memset(cline, 0, sizeof(cline));
free(d13);
free(d23);
free(overlap);
free(de);

de = d13 = d23 = NULL((void *)0);
overlap = NULL((void *)0);

increase();

/* fds[0] and fds[1] are closed in readin() */
m = readin(fds[0], &d13);
12
←
Calling 'readin'→
n = readin(fds[1], &d23);

for (i = 0; i <= 2; i++) {
if ((fp[i] = fdopen(fds[i + 2], "r")) == NULL((void *)0)) {
	cvs_log(LP_ERR1, "%s", argv[i + 2]);
	return (-1);
}
}

return (merge(m, n));
315}

317int
318ed_patch_lines(struct rcs_lines *dlines, struct rcs_lines *plines)
319{
char op, *ep;
struct rcs_line *sort, *lp, *dlp, *ndlp, *insert_after;
int start, end, i, lineno;
u_char tmp;

dlp = TAILQ_FIRST(&(dlines->l_lines))((&(dlines->l_lines))->tqh_first);
lp = TAILQ_FIRST(&(plines->l_lines))((&(plines->l_lines))->tqh_first);

end = 0;
for (lp = TAILQ_NEXT(lp, l_list)((lp)->l_list.tqe_next); lp != NULL((void *)0);
   lp = TAILQ_NEXT(lp, l_list)((lp)->l_list.tqe_next)) {
/* Skip blank lines */
if (lp->l_len < 2)
	continue;

/* NUL-terminate line buffer for strtol() safety. */
tmp = lp->l_line[lp->l_len - 1];
lp->l_line[lp->l_len - 1] = '\0';

op = lp->l_line[strlen(lp->l_line) - 1];
start = (int)strtol(lp->l_line, &ep, 10);

/* Restore the last byte of the buffer */
lp->l_line[lp->l_len - 1] = tmp;

if (op == 'a') {
	if (start > dlines->l_nblines ||
	    start < 0 || *ep != 'a')
		fatal("ed_patch_lines %d", start);
} else if (op == 'c') {
	if (start > dlines->l_nblines ||
	    start < 0 || (*ep != ',' && *ep != 'c'))
		fatal("ed_patch_lines");

	if (*ep == ',') {
		ep++;
		end = (int)strtol(ep, &ep, 10);
		if (end < 0 || *ep != 'c')
			fatal("ed_patch_lines");
	} else {
		end = start;
	}
} else {
	fatal("invalid op %c found while merging", op);
}


for (;;) {
	if (dlp == NULL((void *)0))
		break;
	if (dlp->l_lineno == start)
		break;
	if (dlp->l_lineno > start) {
		dlp = TAILQ_PREV(dlp, tqh, l_list)(*(((struct tqh *)((dlp)->l_list.tqe_prev))->tqh_last));
	} else if (dlp->l_lineno < start) {
		ndlp = TAILQ_NEXT(dlp, l_list)((dlp)->l_list.tqe_next);
		if (ndlp->l_lineno > start)
			break;
		dlp = ndlp;
	}
}

if (dlp == NULL((void *)0))
	fatal("ed_patch_lines");


if (op == 'c') {
	insert_after = TAILQ_PREV(dlp, tqh, l_list)(*(((struct tqh *)((dlp)->l_list.tqe_prev))->tqh_last));
	for (i = 0; i <= (end - start); i++) {
		ndlp = TAILQ_NEXT(dlp, l_list)((dlp)->l_list.tqe_next);
		TAILQ_REMOVE(&(dlines->l_lines), dlp, l_list)do { if (((dlp)->l_list.tqe_next) != ((void *)0)) (dlp)->
l_list.tqe_next->l_list.tqe_prev = (dlp)->l_list.tqe_prev
; else (&(dlines->l_lines))->tqh_last = (dlp)->l_list
.tqe_prev; *(dlp)->l_list.tqe_prev = (dlp)->l_list.tqe_next
; ; ; } while (0);
		dlp = ndlp;
	}
	dlp = insert_after;
}

if (op == 'a' || op == 'c') {
	for (;;) {
		ndlp = lp;
		lp = TAILQ_NEXT(lp, l_list)((lp)->l_list.tqe_next);
		if (lp == NULL((void *)0))
			fatal("ed_patch_lines");

		if (lp->l_len == 2 &&
		    lp->l_line[0] == '.' &&
		    lp->l_line[1] == '\n')
			break;

		TAILQ_REMOVE(&(plines->l_lines), lp, l_list)do { if (((lp)->l_list.tqe_next) != ((void *)0)) (lp)->
l_list.tqe_next->l_list.tqe_prev = (lp)->l_list.tqe_prev
; else (&(plines->l_lines))->tqh_last = (lp)->l_list
.tqe_prev; *(lp)->l_list.tqe_prev = (lp)->l_list.tqe_next
; ; ; } while (0);
		TAILQ_INSERT_AFTER(&(dlines->l_lines), dlp,do { if (((lp)->l_list.tqe_next = (dlp)->l_list.tqe_next
) != ((void *)0)) (lp)->l_list.tqe_next->l_list.tqe_prev
 = &(lp)->l_list.tqe_next; else (&(dlines->l_lines
))->tqh_last = &(lp)->l_list.tqe_next; (dlp)->l_list
.tqe_next = (lp); (lp)->l_list.tqe_prev = &(dlp)->l_list
.tqe_next; } while (0)
		    lp, l_list)do { if (((lp)->l_list.tqe_next = (dlp)->l_list.tqe_next
) != ((void *)0)) (lp)->l_list.tqe_next->l_list.tqe_prev
 = &(lp)->l_list.tqe_next; else (&(dlines->l_lines
))->tqh_last = &(lp)->l_list.tqe_next; (dlp)->l_list
.tqe_next = (lp); (lp)->l_list.tqe_prev = &(dlp)->l_list
.tqe_next; } while (0);
		dlp = lp;

		lp->l_lineno = start;
		lp = ndlp;
	}
}

/*
 * always resort lines as the markers might be put at the
 * same line as we first started editing.
 */
lineno = 0;
TAILQ_FOREACH(sort, &(dlines->l_lines), l_list)for((sort) = ((&(dlines->l_lines))->tqh_first); (sort
) != ((void *)0); (sort) = ((sort)->l_list.tqe_next))
	sort->l_lineno = lineno++;
dlines->l_nblines = lineno - 1;
}

return (0);
429}

431/*
* Pick up the line numbers of all changes from one change file.
* (This puts the numbers in a vector, which is not strictly necessary,
* since the vector is processed in one sequential pass.
* The vector could be optimized out of existence)
*/
437static size_t
438readin(int fd, struct diff **dd)
439{
int a, b, c, d;
char kind, *p;
size_t i;

fp[0] = fdopen(fd, "r");
if (fp[0] == NULL((void *)0))
13
←
Assuming the condition is false→
14
←
Taking false branch→
fatal("readin: fdopen: %s", strerror(errno(*__errno())));

for (i = 0; (p = getchange(fp[0])); i++) {
15
←
Calling 'getchange'→
if (i >= szchanges - 1)
	increase();
a = b = number(&p);
if (*p == ',') {
	p++;
	b = number(&p);
}
kind = *p++;
c = d = number(&p);
if (*p==',') {
	p++;
	d = number(&p);
}
if (kind == 'a')
	a++;
if (kind == 'd')
	c++;
b++;
d++;
(*dd)[i].old.from = a;
(*dd)[i].old.to = b;
(*dd)[i].new.from = c;
(*dd)[i].new.to = d;
}

if (i) {
(*dd)[i].old.from = (*dd)[i-1].old.to;
(*dd)[i].new.from = (*dd)[i-1].new.to;
}

(void)fclose(fp[0]);

return (i);
482}

484static int
485number(char **lc)
486{
int nn;

nn = 0;
while (isdigit((unsigned char)(**lc)))
nn = nn*10 + *(*lc)++ - '0';

return (nn);
494}

496static char *
497getchange(FILE *b)
498{
char *line;

while ((line = get_line(b, NULL((void *)0)))) {
16
←
Calling 'get_line'→
if (isdigit((unsigned char)line[0]))
	return (line);
}

return (NULL((void *)0));
507}

509static char *
510get_line(FILE *b, size_t *n)
511{
char *cp;
size_t len;
static char *buf;
17
←
'buf' initialized to a null pointer value→
static size_t bufsize;

if ((cp = fgetln(b, &len)) == NULL((void *)0))
18
←
Assuming the condition is false→
19
←
Taking false branch→
return (NULL((void *)0));

if (cp[len - 1] != '\n')
20
←
Assuming the condition is false→
21
←
Taking false branch→
len++;
if (len + 1 > bufsize) {
22
←
Assuming the condition is false→
23
←
Taking false branch→
do {
	bufsize += 1024;
} while (len + 1 > bufsize);
buf = xreallocarray(buf, 1, bufsize);
}
memcpy(buf, cp, len - 1);
24
←
Null pointer passed as 1st argument to memory copy function
buf[len - 1] = '\n';
buf[len] = '\0';
if (n != NULL((void *)0))
*n = len;

return (buf);
535}

537static int
538merge(size_t m1, size_t m2)
539{
struct diff *d1, *d2, *d3;
int dpl, j, t1, t2;

d1 = d13;
d2 = d23;
j = 0;
for (;;) {
t1 = (d1 < d13 + m1);
t2 = (d2 < d23 + m2);
if (!t1 && !t2)
	break;

if (debug) {
	printf("%d,%d=%d,%d %d,%d=%d,%d\n",
	d1->old.from, d1->old.to,
	d1->new.from, d1->new.to,
	d2->old.from, d2->old.to,
	d2->new.from, d2->new.to);
}

/* first file is different from others */
if (!t2 || (t1 && d1->new.to < d2->new.from)) {
	/* stuff peculiar to 1st file */
	if (eflag==0) {
		separate("1");
		change(1, &d1->old, 0);
		keep(2, &d1->new);
		change(3, &d1->new, 0);
	}
	d1++;
	continue;
}

/* second file is different from others */
if (!t1 || (t2 && d2->new.to < d1->new.from)) {
	if (eflag==0) {
		separate("2");
		keep(1, &d2->new);
		change(2, &d2->old, 0);
		change(3, &d2->new, 0);
	}
	d2++;
	continue;
}

/*
 * Merge overlapping changes in first file
 * this happens after extension (see below).
 */
if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
	d1[1].old.from = d1->old.from;
	d1[1].new.from = d1->new.from;
	d1++;
	continue;
}

/* merge overlapping changes in second */
if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
	d2[1].old.from = d2->old.from;
	d2[1].new.from = d2->new.from;
	d2++;
	continue;
}
/* stuff peculiar to third file or different in all */
if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
	dpl = duplicate(&d1->old,&d2->old);
	if (dpl == -1)
		return (-1);

	/*
	 * dpl = 0 means all files differ
	 * dpl = 1 means files 1 and 2 identical
	 */
	if (eflag==0) {
		separate(dpl ? "3" : "");
		change(1, &d1->old, dpl);
		change(2, &d2->old, 0);
		d3 = d1->old.to > d1->old.from ? d1 : d2;
		change(3, &d3->new, 0);
	} else
		j = edit(d1, dpl, j);
	d1++;
	d2++;
	continue;
}

/*
 * Overlapping changes from file 1 and 2; extend changes
 * appropriately to make them coincide.
 */
if (d1->new.from < d2->new.from) {
	d2->old.from -= d2->new.from-d1->new.from;
	d2->new.from = d1->new.from;
} else if (d2->new.from < d1->new.from) {
	d1->old.from -= d1->new.from-d2->new.from;
	d1->new.from = d2->new.from;
}
if (d1->new.to > d2->new.to) {
	d2->old.to += d1->new.to - d2->new.to;
	d2->new.to = d1->new.to;
} else if (d2->new.to > d1->new.to) {
	d1->old.to += d2->new.to - d1->new.to;
	d1->new.to = d2->new.to;
}
}

return (edscript(j));
647}

649static void
650separate(const char *s)
651{
diff_output("====%s\n", s);
653}

655/*
* The range of lines rold.from thru rold.to in file i is to be changed.
* It is to be printed only if it does not duplicate something to be
* printed later.
*/
660static void
661change(int i, struct range *rold, int fdup)
662{
diff_output("%d:", i);
last[i] = rold->to;
prange(rold);
if (fdup || debug)
return;
i--;
(void)skip(i, rold->from, NULL((void *)0));
(void)skip(i, rold->to, "  ");
671}

673/*
* print the range of line numbers, rold.from thru rold.to, as n1,n2 or n1
*/
676static void
677prange(struct range *rold)
678{
if (rold->to <= rold->from)
diff_output("%da\n", rold->from - 1);
else {
diff_output("%d", rold->from);
if (rold->to > rold->from+1)
	diff_output(",%d", rold->to - 1);
diff_output("c\n");
}
687}

689/*
* No difference was reported by diff between file 1 (or 2) and file 3,
* and an artificial dummy difference (trange) must be ginned up to
* correspond to the change reported in the other file.
*/
694static void
695keep(int i, struct range *rnew)
696{
int delta;
struct range trange;

delta = last[3] - last[i];
trange.from = rnew->from - delta;
trange.to = rnew->to - delta;
change(i, &trange, 1);
704}

706/*
* skip to just before line number from in file "i".  If "pr" is non-NULL,
* print all skipped stuff with string pr as a prefix.
*/
710static int
711skip(int i, int from, char *pr)
712{
size_t j, n;
char *line;

for (n = 0; cline[i] < from - 1; n += j) {
if ((line = get_line(fp[i], &j)) == NULL((void *)0))
	return (-1);
if (pr != NULL((void *)0))
	diff_output("%s%s", pr, line);
cline[i]++;
}
return ((int) n);
724}

726/*
* Return 1 or 0 according as the old range (in file 1) contains exactly
* the same data as the new range (in file 2).
*/
730static int
731duplicate(struct range *r1, struct range *r2)
732{
int c,d;
int nchar;
int nline;

if (r1->to-r1->from != r2->to-r2->from)
return (0);
(void)skip(0, r1->from, NULL((void *)0));
(void)skip(1, r2->from, NULL((void *)0));
nchar = 0;
for (nline=0; nline < r1->to - r1->from; nline++) {
do {
	c = getc(fp[0])(!__isthreaded ? (--(fp[0])->_r < 0 ? __srget(fp[0]) : (
int)(*(fp[0])->_p++)) : (getc)(fp[0]));
	d = getc(fp[1])(!__isthreaded ? (--(fp[1])->_r < 0 ? __srget(fp[1]) : (
int)(*(fp[1])->_p++)) : (getc)(fp[1]));
	if (c == -1 && d == -1)
		break;
	if (c == -1 || d== -1)
		return (-1);
	nchar++;
	if (c != d) {
		repos(nchar);
		return (0);
	}
} while (c != '\n');
}
repos(nchar);
return (1);
759}

761static void
762repos(int nchar)
763{
int i;

for (i = 0; i < 2; i++)
(void)fseek(fp[i], (long)-nchar, SEEK_CUR1);
768}

770/*
* collect an editing script for later regurgitation
*/
773static int
774edit(struct diff *diff, int fdup, int j)
775{
if (((fdup + 1) & eflag) == 0)
return (j);
j++;
overlap[j] = !fdup;
if (!fdup)
overlapcnt++;
de[j].old.from = diff->old.from;
de[j].old.to = diff->old.to;
de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, NULL((void *)0));
de[j].new.to = de[j].new.from + skip(2, diff->new.to, NULL((void *)0));
return (j);
787}

789/* regurgitate */
790static int
791edscript(int n)
792{
int j, k;
char block[BUFSIZ1024+1];

for (; n > 0; n--) {
if (!oflag || !overlap[n])
	prange(&de[n].old);
else
	diff_output("%da\n=======\n", de[n].old.to -1);
(void)fseek(fp[2], (long)de[n].new.from, SEEK_SET0);
for (k = de[n].new.to-de[n].new.from; k > 0; k-= j) {
	size_t r;
	j = k > BUFSIZ1024 ? BUFSIZ1024 : k;
	r = fread(block, 1, j, fp[2]);
	if (r == 0) {
		if (feof(fp[2])(!__isthreaded ? (((fp[2])->_flags & 0x0020) != 0) : (
feof)(fp[2])))
			break;
		return (-1);
	}
	if (r != (size_t)j)
		j = r;
	block[j] = '\0';
	diff_output("%s", block);
}

if (!oflag || !overlap[n])
	diff_output(".\n");
else {
	diff_output("%s\n.\n", f3mark);
	diff_output("%da\n%s\n.\n", de[n].old.from - 1, f1mark);
}
}

return (overlapcnt);
826}

828static void
829increase(void)
830{
size_t newsz, incr;

/* are the memset(3) calls needed? */
newsz = szchanges == 0 ? 64 : 2 * szchanges;
incr = newsz - szchanges;

d13 = xreallocarray(d13, newsz, sizeof(*d13));
memset(d13 + szchanges, 0, incr * sizeof(*d13));
d23 = xreallocarray(d23, newsz, sizeof(*d23));
memset(d23 + szchanges, 0, incr * sizeof(*d23));
de = xreallocarray(de, newsz, sizeof(*de));
memset(de + szchanges, 0, incr * sizeof(*de));
overlap = xreallocarray(overlap, newsz, sizeof(*overlap));
memset(overlap + szchanges, 0, incr * sizeof(*overlap));
szchanges = newsz;
846}