add tools

1 files changed, 1485 insertions, 0 deletions

diff --git a/usr.bin/diff/diffreg.c b/usr.bin/diff/diffreg.c
new file mode 100644
index 0000000..fc0029d
--- /dev/null
+++ b/usr.bin/diff/diffreg.c
@@ -0,0 +1,1485 @@
+/*	$OpenBSD: diffreg.c,v 1.93 2019/06/28 13:35:00 deraadt Exp $	*/
+
+/*
+ * 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.
+ */
+/*-
+ * 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.
+ *
+ *	@(#)diffreg.c   8.1 (Berkeley) 6/6/93
+ */
+
+#include <sys/stat.h>
+#include <sys/wait.h>
+
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include "diff.h"
+#include "xmalloc.h"
+
+#define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
+#define MAXIMUM(a, b)	(((a) > (b)) ? (a) : (b))
+
+/*
+ * diff - compare two files.
+ */
+
+/*
+ *	Uses an algorithm due to Harold Stone, which finds
+ *	a pair of longest identical subsequences in the two
+ *	files.
+ *
+ *	The major goal is to generate the match vector J.
+ *	J[i] is the index of the line in file1 corresponding
+ *	to line i file0. J[i] = 0 if there is no
+ *	such line in file1.
+ *
+ *	Lines are hashed so as to work in core. All potential
+ *	matches are located by sorting the lines of each file
+ *	on the hash (called ``value''). In particular, this
+ *	collects the equivalence classes in file1 together.
+ *	Subroutine equiv replaces the value of each line in
+ *	file0 by the index of the first element of its
+ *	matching equivalence in (the reordered) file1.
+ *	To save space equiv squeezes file1 into a single
+ *	array member in which the equivalence classes
+ *	are simply concatenated, except that their first
+ *	members are flagged by changing sign.
+ *
+ *	Next the indices that point into member are unsorted into
+ *	array class according to the original order of file0.
+ *
+ *	The cleverness lies in routine stone. This marches
+ *	through the lines of file0, developing a vector klist
+ *	of "k-candidates". At step i a k-candidate is a matched
+ *	pair of lines x,y (x in file0 y in file1) such that
+ *	there is a common subsequence of length k
+ *	between the first i lines of file0 and the first y
+ *	lines of file1, but there is no such subsequence for
+ *	any smaller y. x is the earliest possible mate to y
+ *	that occurs in such a subsequence.
+ *
+ *	Whenever any of the members of the equivalence class of
+ *	lines in file1 matable to a line in file0 has serial number
+ *	less than the y of some k-candidate, that k-candidate
+ *	with the smallest such y is replaced. The new
+ *	k-candidate is chained (via pred) to the current
+ *	k-1 candidate so that the actual subsequence can
+ *	be recovered. When a member has serial number greater
+ *	that the y of all k-candidates, the klist is extended.
+ *	At the end, the longest subsequence is pulled out
+ *	and placed in the array J by unravel
+ *
+ *	With J in hand, the matches there recorded are
+ *	check'ed against reality to assure that no spurious
+ *	matches have crept in due to hashing. If they have,
+ *	they are broken, and "jackpot" is recorded--a harmless
+ *	matter except that a true match for a spuriously
+ *	mated line may now be unnecessarily reported as a change.
+ *
+ *	Much of the complexity of the program comes simply
+ *	from trying to minimize core utilization and
+ *	maximize the range of doable problems by dynamically
+ *	allocating what is needed and reusing what is not.
+ *	The core requirements for problems larger than somewhat
+ *	are (in words) 2*length(file0) + length(file1) +
+ *	3*(number of k-candidates installed),  typically about
+ *	6n words for files of length n.
+ */
+
+struct cand {
+	int	x;
+	int	y;
+	int	pred;
+};
+
+struct line {
+	int	serial;
+	int	value;
+} *file[2];
+
+/*
+ * The following struct is used to record change information when
+ * doing a "context" or "unified" diff.  (see routine "change" to
+ * understand the highly mnemonic field names)
+ */
+struct context_vec {
+	int	a;		/* start line in old file */
+	int	b;		/* end line in old file */
+	int	c;		/* start line in new file */
+	int	d;		/* end line in new file */
+};
+
+#define	diff_output	printf
+static FILE	*opentemp(const char *);
+static void	 output(char *, FILE *, char *, FILE *, int);
+static void	 check(FILE *, FILE *, int);
+static void	 range(int, int, char *);
+static void	 uni_range(int, int);
+static void	 dump_context_vec(FILE *, FILE *, int);
+static void	 dump_unified_vec(FILE *, FILE *, int);
+static void	 prepare(int, FILE *, off_t, int);
+static void	 prune(void);
+static void	 equiv(struct line *, int, struct line *, int, int *);
+static void	 unravel(int);
+static void	 unsort(struct line *, int, int *);
+static void	 change(char *, FILE *, char *, FILE *, int, int, int, int, int *);
+static void	 sort(struct line *, int);
+static void	 print_header(const char *, const char *);
+static int	 ignoreline(char *);
+static int	 asciifile(FILE *);
+static int	 fetch(long *, int, int, FILE *, int, int, int);
+static int	 newcand(int, int, int);
+static int	 search(int *, int, int);
+static int	 skipline(FILE *);
+static int	 isqrt(int);
+static int	 stone(int *, int, int *, int *, int);
+static int	 readhash(FILE *, int);
+static int	 files_differ(FILE *, FILE *, int);
+static char	*match_function(const long *, int, FILE *);
+static char	*preadline(int, size_t, off_t);
+
+static int  *J;			/* will be overlaid on class */
+static int  *class;		/* will be overlaid on file[0] */
+static int  *klist;		/* will be overlaid on file[0] after class */
+static int  *member;		/* will be overlaid on file[1] */
+static int   clen;
+static int   inifdef;		/* whether or not we are in a #ifdef block */
+static int   len[2];
+static int   pref, suff;	/* length of prefix and suffix */
+static int   slen[2];
+static int   anychange;
+static long *ixnew;		/* will be overlaid on file[1] */
+static long *ixold;		/* will be overlaid on klist */
+static struct cand *clist;	/* merely a free storage pot for candidates */
+static int   clistlen;		/* the length of clist */
+static struct line *sfile[2];	/* shortened by pruning common prefix/suffix */
+static u_char *chrtran;		/* translation table for case-folding */
+static struct context_vec *context_vec_start;
+static struct context_vec *context_vec_end;
+static struct context_vec *context_vec_ptr;
+
+#define FUNCTION_CONTEXT_SIZE	55
+static char lastbuf[FUNCTION_CONTEXT_SIZE];
+static int lastline;
+static int lastmatchline;
+
+
+/*
+ * chrtran points to one of 2 translation tables: cup2low if folding upper to
+ * lower case clow2low if not folding case
+ */
+u_char clow2low[256] = {
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a,
+	0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15,
+	0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
+	0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
+	0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36,
+	0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x41,
+	0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c,
+	0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
+	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x60, 0x61, 0x62,
+	0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d,
+	0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
+	0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83,
+	0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e,
+	0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
+	0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4,
+	0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
+	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba,
+	0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5,
+	0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 0xd0,
+	0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb,
+	0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6,
+	0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0, 0xf1,
+	0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc,
+	0xfd, 0xfe, 0xff
+};
+
+u_char cup2low[256] = {
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a,
+	0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15,
+	0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
+	0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
+	0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36,
+	0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x60, 0x61,
+	0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c,
+	0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x60, 0x61, 0x62,
+	0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d,
+	0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
+	0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83,
+	0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e,
+	0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
+	0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4,
+	0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
+	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba,
+	0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5,
+	0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 0xd0,
+	0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb,
+	0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6,
+	0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0, 0xf1,
+	0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc,
+	0xfd, 0xfe, 0xff
+};
+
+int
+diffreg(char *file1, char *file2, int flags)
+{
+	FILE *f1, *f2;
+	int i, rval;
+
+	f1 = f2 = NULL;
+	rval = D_SAME;
+	anychange = 0;
+	lastline = 0;
+	lastmatchline = 0;
+	context_vec_ptr = context_vec_start - 1;
+	if (flags & D_IGNORECASE)
+		chrtran = cup2low;
+	else
+		chrtran = clow2low;
+	if (S_ISDIR(stb1.st_mode) != S_ISDIR(stb2.st_mode))
+		return (S_ISDIR(stb1.st_mode) ? D_MISMATCH1 : D_MISMATCH2);
+	if (strcmp(file1, "-") == 0 && strcmp(file2, "-") == 0)
+		goto closem;
+
+	if (flags & D_EMPTY1)
+		f1 = fopen(_PATH_DEVNULL, "r");
+	else {
+		if (!S_ISREG(stb1.st_mode)) {
+			if ((f1 = opentemp(file1)) == NULL ||
+			    fstat(fileno(f1), &stb1) == -1) {
+				warn("%s", file1);
+				status |= 2;
+				goto closem;
+			}
+		} else if (strcmp(file1, "-") == 0)
+			f1 = stdin;
+		else
+			f1 = fopen(file1, "r");
+	}
+	if (f1 == NULL) {
+		warn("%s", file1);
+		status |= 2;
+		goto closem;
+	}
+
+	if (flags & D_EMPTY2)
+		f2 = fopen(_PATH_DEVNULL, "r");
+	else {
+		if (!S_ISREG(stb2.st_mode)) {
+			if ((f2 = opentemp(file2)) == NULL ||
+			    fstat(fileno(f2), &stb2) == -1) {
+				warn("%s", file2);
+				status |= 2;
+				goto closem;
+			}
+		} else if (strcmp(file2, "-") == 0)
+			f2 = stdin;
+		else
+			f2 = fopen(file2, "r");
+	}
+	if (f2 == NULL) {
+		warn("%s", file2);
+		status |= 2;
+		goto closem;
+	}
+
+	switch (files_differ(f1, f2, flags)) {
+	case 0:
+		goto closem;
+	case 1:
+		break;
+	default:
+		/* error */
+		status |= 2;
+		goto closem;
+	}
+
+	if ((flags & D_FORCEASCII) == 0 &&
+	    (!asciifile(f1) || !asciifile(f2))) {
+		rval = D_BINARY;
+		status |= 1;
+		goto closem;
+	}
+	prepare(0, f1, stb1.st_size, flags);
+	prepare(1, f2, stb2.st_size, flags);
+
+	prune();
+	sort(sfile[0], slen[0]);
+	sort(sfile[1], slen[1]);
+
+	member = (int *)file[1];
+	equiv(sfile[0], slen[0], sfile[1], slen[1], member);
+	member = xreallocarray(member, slen[1] + 2, sizeof(*member));
+
+	class = (int *)file[0];
+	unsort(sfile[0], slen[0], class);
+	class = xreallocarray(class, slen[0] + 2, sizeof(*class));
+
+	klist = xcalloc(slen[0] + 2, sizeof(*klist));
+	clen = 0;
+	clistlen = 100;
+	clist = xcalloc(clistlen, sizeof(*clist));
+	i = stone(class, slen[0], member, klist, flags);
+	free(member);
+	free(class);
+
+	J = xreallocarray(J, len[0] + 2, sizeof(*J));
+	unravel(klist[i]);
+	free(clist);
+	free(klist);
+
+	ixold = xreallocarray(ixold, len[0] + 2, sizeof(*ixold));
+	ixnew = xreallocarray(ixnew, len[1] + 2, sizeof(*ixnew));
+	check(f1, f2, flags);
+	output(file1, f1, file2, f2, flags);
+closem:
+	if (anychange) {
+		status |= 1;
+		if (rval == D_SAME)
+			rval = D_DIFFER;
+	}
+	if (f1 != NULL)
+		fclose(f1);
+	if (f2 != NULL)
+		fclose(f2);
+
+	return (rval);
+}
+
+/*
+ * Check to see if the given files differ.
+ * Returns 0 if they are the same, 1 if different, and -1 on error.
+ * XXX - could use code from cmp(1) [faster]
+ */
+static int
+files_differ(FILE *f1, FILE *f2, int flags)
+{
+	char buf1[BUFSIZ], buf2[BUFSIZ];
+	size_t i, j;
+
+	if ((flags & (D_EMPTY1|D_EMPTY2)) || stb1.st_size != stb2.st_size ||
+	    (stb1.st_mode & S_IFMT) != (stb2.st_mode & S_IFMT))
+		return (1);
+	for (;;) {
+		i = fread(buf1, 1, sizeof(buf1), f1);
+		j = fread(buf2, 1, sizeof(buf2), f2);
+		if ((!i && ferror(f1)) || (!j && ferror(f2)))
+			return (-1);
+		if (i != j)
+			return (1);
+		if (i == 0)
+			return (0);
+		if (memcmp(buf1, buf2, i) != 0)
+			return (1);
+	}
+}
+
+static FILE *
+opentemp(const char *file)
+{
+	char buf[BUFSIZ], tempfile[PATH_MAX];
+	ssize_t nread;
+	int ifd, ofd;
+
+	if (strcmp(file, "-") == 0)
+		ifd = STDIN_FILENO;
+	else if ((ifd = open(file, O_RDONLY, 0644)) == -1)
+		return (NULL);
+
+	(void)strlcpy(tempfile, _PATH_TMP "/diff.XXXXXXXX", sizeof(tempfile));
+
+	if ((ofd = mkstemp(tempfile)) == -1) {
+		close(ifd);
+		return (NULL);
+	}
+	unlink(tempfile);
+	while ((nread = read(ifd, buf, BUFSIZ)) > 0) {
+		if (write(ofd, buf, nread) != nread) {
+			close(ifd);
+			close(ofd);
+			return (NULL);
+		}
+	}
+	close(ifd);
+	lseek(ofd, (off_t)0, SEEK_SET);
+	return (fdopen(ofd, "r"));
+}
+
+char *
+splice(char *dir, char *file)
+{
+	char *tail, *buf;
+	size_t dirlen;
+
+	dirlen = strlen(dir);
+	while (dirlen != 0 && dir[dirlen - 1] == '/')
+	    dirlen--;
+	if ((tail = strrchr(file, '/')) == NULL)
+		tail = file;
+	else
+		tail++;
+	xasprintf(&buf, "%.*s/%s", (int)dirlen, dir, tail);
+	return (buf);
+}
+
+static void
+prepare(int i, FILE *fd, off_t filesize, int flags)
+{
+	struct line *p;
+	int j, h;
+	size_t sz;
+
+	rewind(fd);
+
+	sz = (filesize <= SIZE_MAX ? filesize : SIZE_MAX) / 25;
+	if (sz < 100)
+		sz = 100;
+
+	p = xcalloc(sz + 3, sizeof(*p));
+	for (j = 0; (h = readhash(fd, flags));) {
+		if (j == sz) {
+			sz = sz * 3 / 2;
+			p = xreallocarray(p, sz + 3, sizeof(*p));
+		}
+		p[++j].value = h;
+	}
+	len[i] = j;
+	file[i] = p;
+}
+
+static void
+prune(void)
+{
+	int i, j;
+
+	for (pref = 0; pref < len[0] && pref < len[1] &&
+	    file[0][pref + 1].value == file[1][pref + 1].value;
+	    pref++)
+		;
+	for (suff = 0; suff < len[0] - pref && suff < len[1] - pref &&
+	    file[0][len[0] - suff].value == file[1][len[1] - suff].value;
+	    suff++)
+		;
+	for (j = 0; j < 2; j++) {
+		sfile[j] = file[j] + pref;
+		slen[j] = len[j] - pref - suff;
+		for (i = 0; i <= slen[j]; i++)
+			sfile[j][i].serial = i;
+	}
+}
+
+static void
+equiv(struct line *a, int n, struct line *b, int m, int *c)
+{
+	int i, j;
+
+	i = j = 1;
+	while (i <= n && j <= m) {
+		if (a[i].value < b[j].value)
+			a[i++].value = 0;
+		else if (a[i].value == b[j].value)
+			a[i++].value = j;
+		else
+			j++;
+	}
+	while (i <= n)
+		a[i++].value = 0;
+	b[m + 1].value = 0;
+	j = 0;
+	while (++j <= m) {
+		c[j] = -b[j].serial;
+		while (b[j + 1].value == b[j].value) {
+			j++;
+			c[j] = b[j].serial;
+		}
+	}
+	c[j] = -1;
+}
+
+/* Code taken from ping.c */
+static int
+isqrt(int n)
+{
+	int y, x = 1;
+
+	if (n == 0)
+		return (0);
+
+	do { /* newton was a stinker */
+		y = x;
+		x = n / x;
+		x += y;
+		x /= 2;
+	} while ((x - y) > 1 || (x - y) < -1);
+
+	return (x);
+}
+
+static int
+stone(int *a, int n, int *b, int *c, int flags)
+{
+	int i, k, y, j, l;
+	int oldc, tc, oldl, sq;
+	u_int numtries, bound;
+
+	if (flags & D_MINIMAL)
+		bound = UINT_MAX;
+	else {
+		sq = isqrt(n);
+		bound = MAXIMUM(256, sq);
+	}
+
+	k = 0;
+	c[0] = newcand(0, 0, 0);
+	for (i = 1; i <= n; i++) {
+		j = a[i];
+		if (j == 0)
+			continue;
+		y = -b[j];
+		oldl = 0;
+		oldc = c[0];
+		numtries = 0;
+		do {
+			if (y <= clist[oldc].y)
+				continue;
+			l = search(c, k, y);
+			if (l != oldl + 1)
+				oldc = c[l - 1];
+			if (l <= k) {
+				if (clist[c[l]].y <= y)
+					continue;
+				tc = c[l];
+				c[l] = newcand(i, y, oldc);
+				oldc = tc;
+				oldl = l;
+				numtries++;
+			} else {
+				c[l] = newcand(i, y, oldc);
+				k++;
+				break;
+			}
+		} while ((y = b[++j]) > 0 && numtries < bound);
+	}
+	return (k);
+}
+
+static int
+newcand(int x, int y, int pred)
+{
+	struct cand *q;
+
+	if (clen == clistlen) {
+		clistlen = clistlen * 11 / 10;
+		clist = xreallocarray(clist, clistlen, sizeof(*clist));
+	}
+	q = clist + clen;
+	q->x = x;
+	q->y = y;
+	q->pred = pred;
+	return (clen++);
+}
+
+static int
+search(int *c, int k, int y)
+{
+	int i, j, l, t;
+
+	if (clist[c[k]].y < y)	/* quick look for typical case */
+		return (k + 1);
+	i = 0;
+	j = k + 1;
+	for (;;) {
+		l = (i + j) / 2;
+		if (l <= i)
+			break;
+		t = clist[c[l]].y;
+		if (t > y)
+			j = l;
+		else if (t < y)
+			i = l;
+		else
+			return (l);
+	}
+	return (l + 1);
+}
+
+static void
+unravel(int p)
+{
+	struct cand *q;
+	int i;
+
+	for (i = 0; i <= len[0]; i++)
+		J[i] = i <= pref ? i :
+		    i > len[0] - suff ? i + len[1] - len[0] : 0;
+	for (q = clist + p; q->y != 0; q = clist + q->pred)
+		J[q->x + pref] = q->y + pref;
+}
+
+/*
+ * Check does double duty:
+ *  1.	ferret out any fortuitous correspondences due
+ *	to confounding by hashing (which result in "jackpot")
+ *  2.  collect random access indexes to the two files
+ */
+static void
+check(FILE *f1, FILE *f2, int flags)
+{
+	int i, j, jackpot, c, d;
+	long ctold, ctnew;
+
+	rewind(f1);
+	rewind(f2);
+	j = 1;
+	ixold[0] = ixnew[0] = 0;
+	jackpot = 0;
+	ctold = ctnew = 0;
+	for (i = 1; i <= len[0]; i++) {
+		if (J[i] == 0) {
+			ixold[i] = ctold += skipline(f1);
+			continue;
+		}
+		while (j < J[i]) {
+			ixnew[j] = ctnew += skipline(f2);
+			j++;
+		}
+		if (flags & (D_FOLDBLANKS|D_IGNOREBLANKS|D_IGNORECASE)) {
+			for (;;) {
+				c = getc(f1);
+				d = getc(f2);
+				/*
+				 * GNU diff ignores a missing newline
+				 * in one file for -b or -w.
+				 */
+				if (flags & (D_FOLDBLANKS|D_IGNOREBLANKS)) {
+					if (c == EOF && d == '\n') {
+						ctnew++;
+						break;
+					} else if (c == '\n' && d == EOF) {
+						ctold++;
+						break;
+					}
+				}
+				ctold++;
+				ctnew++;
+				if ((flags & D_FOLDBLANKS) && isspace(c) &&
+				    isspace(d)) {
+					do {
+						if (c == '\n')
+							break;
+						ctold++;
+					} while (isspace(c = getc(f1)));
+					do {
+						if (d == '\n')
+							break;
+						ctnew++;
+					} while (isspace(d = getc(f2)));
+				} else if ((flags & D_IGNOREBLANKS)) {
+					while (isspace(c) && c != '\n') {
+						c = getc(f1);
+						ctold++;
+					}
+					while (isspace(d) && d != '\n') {
+						d = getc(f2);
+						ctnew++;
+					}
+				}
+				if (chrtran[c] != chrtran[d]) {
+					jackpot++;
+					J[i] = 0;
+					if (c != '\n' && c != EOF)
+						ctold += skipline(f1);
+					if (d != '\n' && c != EOF)
+						ctnew += skipline(f2);
+					break;
+				}
+				if (c == '\n' || c == EOF)
+					break;
+			}
+		} else {
+			for (;;) {
+				ctold++;
+				ctnew++;
+				if ((c = getc(f1)) != (d = getc(f2))) {
+					/* jackpot++; */
+					J[i] = 0;
+					if (c != '\n' && c != EOF)
+						ctold += skipline(f1);
+					if (d != '\n' && c != EOF)
+						ctnew += skipline(f2);
+					break;
+				}
+				if (c == '\n' || c == EOF)
+					break;
+			}
+		}
+		ixold[i] = ctold;
+		ixnew[j] = ctnew;
+		j++;
+	}
+	for (; j <= len[1]; j++)
+		ixnew[j] = ctnew += skipline(f2);
+	/*
+	 * if (jackpot)
+	 *	fprintf(stderr, "jackpot\n");
+	 */
+}
+
+/* shellsort CACM #201 */
+static void
+sort(struct line *a, int n)
+{
+	struct line *ai, *aim, w;
+	int j, m = 0, k;
+
+	if (n == 0)
+		return;
+	for (j = 1; j <= n; j *= 2)
+		m = 2 * j - 1;
+	for (m /= 2; m != 0; m /= 2) {
+		k = n - m;
+		for (j = 1; j <= k; j++) {
+			for (ai = &a[j]; ai > a; ai -= m) {
+				aim = &ai[m];
+				if (aim < ai)
+					break;	/* wraparound */
+				if (aim->value > ai[0].value ||
+				    (aim->value == ai[0].value &&
+					aim->serial > ai[0].serial))
+					break;
+				w.value = ai[0].value;
+				ai[0].value = aim->value;
+				aim->value = w.value;
+				w.serial = ai[0].serial;
+				ai[0].serial = aim->serial;
+				aim->serial = w.serial;
+			}
+		}
+	}
+}
+
+static void
+unsort(struct line *f, int l, int *b)
+{
+	int *a, i;
+
+	a = xcalloc(l + 1, sizeof(*a));
+	for (i = 1; i <= l; i++)
+		a[f[i].serial] = f[i].value;
+	for (i = 1; i <= l; i++)
+		b[i] = a[i];
+	free(a);
+}
+
+static int
+skipline(FILE *f)
+{
+	int i, c;
+
+	for (i = 1; (c = getc(f)) != '\n' && c != EOF; i++)
+		continue;
+	return (i);
+}
+
+static void
+output(char *file1, FILE *f1, char *file2, FILE *f2, int flags)
+{
+	int m, i0, i1, j0, j1;
+
+	rewind(f1);
+	rewind(f2);
+	m = len[0];
+	J[0] = 0;
+	J[m + 1] = len[1] + 1;
+	if (diff_format != D_EDIT) {
+		for (i0 = 1; i0 <= m; i0 = i1 + 1) {
+			while (i0 <= m && J[i0] == J[i0 - 1] + 1)
+				i0++;
+			j0 = J[i0 - 1] + 1;
+			i1 = i0 - 1;
+			while (i1 < m && J[i1 + 1] == 0)
+				i1++;
+			j1 = J[i1 + 1] - 1;
+			J[i1] = j1;
+			change(file1, f1, file2, f2, i0, i1, j0, j1, &flags);
+		}
+	} else {
+		for (i0 = m; i0 >= 1; i0 = i1 - 1) {
+			while (i0 >= 1 && J[i0] == J[i0 + 1] - 1 && J[i0] != 0)
+				i0--;
+			j0 = J[i0 + 1] - 1;
+			i1 = i0 + 1;
+			while (i1 > 1 && J[i1 - 1] == 0)
+				i1--;
+			j1 = J[i1 - 1] + 1;
+			J[i1] = j1;
+			change(file1, f1, file2, f2, i1, i0, j1, j0, &flags);
+		}
+	}
+	if (m == 0)
+		change(file1, f1, file2, f2, 1, 0, 1, len[1], &flags);
+	if (diff_format == D_IFDEF) {
+		for (;;) {
+#define	c i0
+			if ((c = getc(f1)) == EOF)
+				return;
+			diff_output("%c", c);
+		}
+#undef c
+	}
+	if (anychange != 0) {
+		if (diff_format == D_CONTEXT)
+			dump_context_vec(f1, f2, flags);
+		else if (diff_format == D_UNIFIED)
+			dump_unified_vec(f1, f2, flags);
+	}
+}
+
+static void
+range(int a, int b, char *separator)
+{
+	diff_output("%d", a > b ? b : a);
+	if (a < b)
+		diff_output("%s%d", separator, b);
+}
+
+static void
+uni_range(int a, int b)
+{
+	if (a < b)
+		diff_output("%d,%d", a, b - a + 1);
+	else if (a == b)
+		diff_output("%d", b);
+	else
+		diff_output("%d,0", b);
+}
+
+static char *
+preadline(int fd, size_t rlen, off_t off)
+{
+	char *line;
+	ssize_t nr;
+
+	line = xmalloc(rlen + 1);
+	if ((nr = pread(fd, line, rlen, off)) == -1)
+		err(2, "preadline");
+	if (nr > 0 && line[nr-1] == '\n')
+		nr--;
+	line[nr] = '\0';
+	return (line);
+}
+
+static int
+ignoreline(char *line)
+{
+	int ret;
+
+	ret = regexec(&ignore_re, line, 0, NULL, 0);
+	free(line);
+	return (ret == 0);	/* if it matched, it should be ignored. */
+}
+
+/*
+ * Indicate that there is a difference between lines a and b of the from file
+ * to get to lines c to d of the to file.  If a is greater then b then there
+ * are no lines in the from file involved and this means that there were
+ * lines appended (beginning at b).  If c is greater than d then there are
+ * lines missing from the to file.
+ */
+static void
+change(char *file1, FILE *f1, char *file2, FILE *f2, int a, int b, int c, int d,
+    int *pflags)
+{
+	static size_t max_context = 64;
+	int i;
+
+restart:
+	if (diff_format != D_IFDEF && a > b && c > d)
+		return;
+	if (ignore_pats != NULL) {
+		char *line;
+		/*
+		 * All lines in the change, insert, or delete must
+		 * match an ignore pattern for the change to be
+		 * ignored.
+		 */
+		if (a <= b) {		/* Changes and deletes. */
+			for (i = a; i <= b; i++) {
+				line = preadline(fileno(f1),
+				    ixold[i] - ixold[i - 1], ixold[i - 1]);
+				if (!ignoreline(line))
+					goto proceed;
+			}
+		}
+		if (a > b || c <= d) {	/* Changes and inserts. */
+			for (i = c; i <= d; i++) {
+				line = preadline(fileno(f2),
+				    ixnew[i] - ixnew[i - 1], ixnew[i - 1]);
+				if (!ignoreline(line))
+					goto proceed;
+			}
+		}
+		return;
+	}
+proceed:
+	if (*pflags & D_HEADER) {
+		diff_output("%s %s %s\n", diffargs, file1, file2);
+		*pflags &= ~D_HEADER;
+	}
+	if (diff_format == D_CONTEXT || diff_format == D_UNIFIED) {
+		/*
+		 * Allocate change records as needed.
+		 */
+		if (context_vec_ptr == context_vec_end - 1) {
+			ptrdiff_t offset = context_vec_ptr - context_vec_start;
+			max_context <<= 1;
+			context_vec_start = xreallocarray(context_vec_start,
+			    max_context, sizeof(*context_vec_start));
+			context_vec_end = context_vec_start + max_context;
+			context_vec_ptr = context_vec_start + offset;
+		}
+		if (anychange == 0) {
+			/*
+			 * Print the context/unidiff header first time through.
+			 */
+			print_header(file1, file2);
+			anychange = 1;
+		} else if (a > context_vec_ptr->b + (2 * diff_context) + 1 &&
+		    c > context_vec_ptr->d + (2 * diff_context) + 1) {
+			/*
+			 * If this change is more than 'diff_context' lines from the
+			 * previous change, dump the record and reset it.
+			 */
+			if (diff_format == D_CONTEXT)
+				dump_context_vec(f1, f2, *pflags);
+			else
+				dump_unified_vec(f1, f2, *pflags);
+		}
+		context_vec_ptr++;
+		context_vec_ptr->a = a;
+		context_vec_ptr->b = b;
+		context_vec_ptr->c = c;
+		context_vec_ptr->d = d;
+		return;
+	}
+	if (anychange == 0)
+		anychange = 1;
+	switch (diff_format) {
+	case D_BRIEF:
+		return;
+	case D_NORMAL:
+	case D_EDIT:
+		range(a, b, ",");
+		diff_output("%c", a > b ? 'a' : c > d ? 'd' : 'c');
+		if (diff_format == D_NORMAL)
+			range(c, d, ",");
+		diff_output("\n");
+		break;
+	case D_REVERSE:
+		diff_output("%c", a > b ? 'a' : c > d ? 'd' : 'c');
+		range(a, b, " ");
+		diff_output("\n");
+		break;
+	case D_NREVERSE:
+		if (a > b)
+			diff_output("a%d %d\n", b, d - c + 1);
+		else {
+			diff_output("d%d %d\n", a, b - a + 1);
+			if (!(c > d))
+				/* add changed lines */
+				diff_output("a%d %d\n", b, d - c + 1);
+		}
+		break;
+	}
+	if (diff_format == D_NORMAL || diff_format == D_IFDEF) {
+		fetch(ixold, a, b, f1, '<', 1, *pflags);
+		if (a <= b && c <= d && diff_format == D_NORMAL)
+			diff_output("---\n");
+	}
+	i = fetch(ixnew, c, d, f2, diff_format == D_NORMAL ? '>' : '\0', 0, *pflags);
+	if (i != 0 && diff_format == D_EDIT) {
+		/*
+		 * A non-zero return value for D_EDIT indicates that the
+		 * last line printed was a bare dot (".") that has been
+		 * escaped as ".." to prevent ed(1) from misinterpreting
+		 * it.  We have to add a substitute command to change this
+		 * back and restart where we left off.
+		 */
+		diff_output(".\n");
+		diff_output("%ds/.//\n", a + i - 1);
+		b = a + i - 1;
+		a = b + 1;
+		c += i;
+		goto restart;
+	}
+	if ((diff_format == D_EDIT || diff_format == D_REVERSE) && c <= d)
+		diff_output(".\n");
+	if (inifdef) {
+		diff_output("#endif /* %s */\n", ifdefname);
+		inifdef = 0;
+	}
+}
+
+static int
+fetch(long *f, int a, int b, FILE *lb, int ch, int oldfile, int flags)
+{
+	int i, j, c, lastc, col, nc;
+
+	/*
+	 * When doing #ifdef's, copy down to current line
+	 * if this is the first file, so that stuff makes it to output.
+	 */
+	if (diff_format == D_IFDEF && oldfile) {
+		long curpos = ftell(lb);
+		/* print through if append (a>b), else to (nb: 0 vs 1 orig) */
+		nc = f[a > b ? b : a - 1] - curpos;
+		for (i = 0; i < nc; i++)
+			diff_output("%c", getc(lb));
+	}
+	if (a > b)
+		return (0);
+	if (diff_format == D_IFDEF) {
+		if (inifdef) {
+			diff_output("#else /* %s%s */\n",
+			    oldfile == 1 ? "!" : "", ifdefname);
+		} else {
+			if (oldfile)
+				diff_output("#ifndef %s\n", ifdefname);
+			else
+				diff_output("#ifdef %s\n", ifdefname);
+		}
+		inifdef = 1 + oldfile;
+	}
+	for (i = a; i <= b; i++) {
+		fseek(lb, f[i - 1], SEEK_SET);
+		nc = f[i] - f[i - 1];
+		if (diff_format != D_IFDEF && ch != '\0') {
+			diff_output("%c", ch);
+			if (Tflag && (diff_format == D_NORMAL || diff_format == D_CONTEXT
+			    || diff_format == D_UNIFIED))
+				diff_output("\t");
+			else if (diff_format != D_UNIFIED)
+				diff_output(" ");
+		}
+		col = 0;
+		for (j = 0, lastc = '\0'; j < nc; j++, lastc = c) {
+			if ((c = getc(lb)) == EOF) {
+				if (diff_format == D_EDIT || diff_format == D_REVERSE ||
+				    diff_format == D_NREVERSE)
+					warnx("No newline at end of file");
+				else
+					diff_output("\n\\ No newline at end of "
+					    "file\n");
+				return (0);
+			}
+			if (c == '\t' && (flags & D_EXPANDTABS)) {
+				do {
+					diff_output(" ");
+				} while (++col & 7);
+			} else {
+				if (diff_format == D_EDIT && j == 1 && c == '\n'
+				    && lastc == '.') {
+					/*
+					 * Don't print a bare "." line
+					 * since that will confuse ed(1).
+					 * Print ".." instead and return,
+					 * giving the caller an offset
+					 * from which to restart.
+					 */
+					diff_output(".\n");
+					return (i - a + 1);
+				}
+				diff_output("%c", c);
+				col++;
+			}
+		}
+	}
+	return (0);
+}
+
+/*
+ * Hash function taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578.
+ */
+static int
+readhash(FILE *f, int flags)
+{
+	int i, t, space;
+	int sum;
+
+	sum = 1;
+	space = 0;
+	if ((flags & (D_FOLDBLANKS|D_IGNOREBLANKS)) == 0) {
+		if (flags & D_IGNORECASE)
+			for (i = 0; (t = getc(f)) != '\n'; i++) {
+				if (t == EOF) {
+					if (i == 0)
+						return (0);
+					break;
+				}
+				sum = sum * 127 + chrtran[t];
+			}
+		else
+			for (i = 0; (t = getc(f)) != '\n'; i++) {
+				if (t == EOF) {
+					if (i == 0)
+						return (0);
+					break;
+				}
+				sum = sum * 127 + t;
+			}
+	} else {
+		for (i = 0;;) {
+			switch (t = getc(f)) {
+			case '\t':
+			case '\r':
+			case '\v':
+			case '\f':
+			case ' ':
+				space++;
+				continue;
+			default:
+				if (space && (flags & D_IGNOREBLANKS) == 0) {
+					i++;
+					space = 0;
+				}
+				sum = sum * 127 + chrtran[t];
+				i++;
+				continue;
+			case EOF:
+				if (i == 0)
+					return (0);
+				/* FALLTHROUGH */
+			case '\n':
+				break;
+			}
+			break;
+		}
+	}
+	/*
+	 * There is a remote possibility that we end up with a zero sum.
+	 * Zero is used as an EOF marker, so return 1 instead.
+	 */
+	return (sum == 0 ? 1 : sum);
+}
+
+static int
+asciifile(FILE *f)
+{
+	unsigned char buf[BUFSIZ];
+	size_t cnt;
+
+	if (f == NULL)
+		return (1);
+
+	rewind(f);
+	cnt = fread(buf, 1, sizeof(buf), f);
+	return (memchr(buf, '\0', cnt) == NULL);
+}
+
+#define begins_with(s, pre) (strncmp(s, pre, sizeof(pre)-1) == 0)
+
+static char *
+match_function(const long *f, int pos, FILE *fp)
+{
+	unsigned char buf[FUNCTION_CONTEXT_SIZE];
+	size_t nc;
+	int last = lastline;
+	char *state = NULL;
+
+	lastline = pos;
+	while (pos > last) {
+		fseek(fp, f[pos - 1], SEEK_SET);
+		nc = f[pos] - f[pos - 1];
+		if (nc >= sizeof(buf))
+			nc = sizeof(buf) - 1;
+		nc = fread(buf, 1, nc, fp);
+		if (nc > 0) {
+			buf[nc] = '\0';
+			buf[strcspn(buf, "\n")] = '\0';
+			if (isalpha(buf[0]) || buf[0] == '_' || buf[0] == '$') {
+				if (begins_with(buf, "private:")) {
+					if (!state)
+						state = " (private)";
+				} else if (begins_with(buf, "protected:")) {
+					if (!state)
+						state = " (protected)";
+				} else if (begins_with(buf, "public:")) {
+					if (!state)
+						state = " (public)";
+				} else {
+					strlcpy(lastbuf, buf, sizeof lastbuf);
+					if (state)
+						strlcat(lastbuf, state,
+						    sizeof lastbuf);
+					lastmatchline = pos;
+					return lastbuf;
+				}
+			}
+		}
+		pos--;
+	}
+	return lastmatchline > 0 ? lastbuf : NULL;
+}
+
+/* dump accumulated "context" diff changes */
+static void
+dump_context_vec(FILE *f1, FILE *f2, int flags)
+{
+	struct context_vec *cvp = context_vec_start;
+	int lowa, upb, lowc, upd, do_output;
+	int a, b, c, d;
+	char ch, *f;
+
+	if (context_vec_start > context_vec_ptr)
+		return;
+
+	b = d = 0;		/* gcc */
+	lowa = MAXIMUM(1, cvp->a - diff_context);
+	upb = MINIMUM(len[0], context_vec_ptr->b + diff_context);
+	lowc = MAXIMUM(1, cvp->c - diff_context);
+	upd = MINIMUM(len[1], context_vec_ptr->d + diff_context);
+
+	diff_output("***************");
+	if ((flags & D_PROTOTYPE)) {
+		f = match_function(ixold, lowa-1, f1);
+		if (f != NULL)
+			diff_output(" %s", f);
+	}
+	diff_output("\n*** ");
+	range(lowa, upb, ",");
+	diff_output(" ****\n");
+
+	/*
+	 * Output changes to the "old" file.  The first loop suppresses
+	 * output if there were no changes to the "old" file (we'll see
+	 * the "old" lines as context in the "new" list).
+	 */
+	do_output = 0;
+	for (; cvp <= context_vec_ptr; cvp++)
+		if (cvp->a <= cvp->b) {
+			cvp = context_vec_start;
+			do_output++;
+			break;
+		}
+	if (do_output) {
+		while (cvp <= context_vec_ptr) {
+			a = cvp->a;
+			b = cvp->b;
+			c = cvp->c;
+			d = cvp->d;
+
+			if (a <= b && c <= d)
+				ch = 'c';
+			else
+				ch = (a <= b) ? 'd' : 'a';
+
+			if (ch == 'a')
+				fetch(ixold, lowa, b, f1, ' ', 0, flags);
+			else {
+				fetch(ixold, lowa, a - 1, f1, ' ', 0, flags);
+				fetch(ixold, a, b, f1,
+				    ch == 'c' ? '!' : '-', 0, flags);
+			}
+			lowa = b + 1;
+			cvp++;
+		}
+		fetch(ixold, b + 1, upb, f1, ' ', 0, flags);
+	}
+	/* output changes to the "new" file */
+	diff_output("--- ");
+	range(lowc, upd, ",");
+	diff_output(" ----\n");
+
+	do_output = 0;
+	for (cvp = context_vec_start; cvp <= context_vec_ptr; cvp++)
+		if (cvp->c <= cvp->d) {
+			cvp = context_vec_start;
+			do_output++;
+			break;
+		}
+	if (do_output) {
+		while (cvp <= context_vec_ptr) {
+			a = cvp->a;
+			b = cvp->b;
+			c = cvp->c;
+			d = cvp->d;
+
+			if (a <= b && c <= d)
+				ch = 'c';
+			else
+				ch = (a <= b) ? 'd' : 'a';
+
+			if (ch == 'd')
+				fetch(ixnew, lowc, d, f2, ' ', 0, flags);
+			else {
+				fetch(ixnew, lowc, c - 1, f2, ' ', 0, flags);
+				fetch(ixnew, c, d, f2,
+				    ch == 'c' ? '!' : '+', 0, flags);
+			}
+			lowc = d + 1;
+			cvp++;
+		}
+		fetch(ixnew, d + 1, upd, f2, ' ', 0, flags);
+	}
+	context_vec_ptr = context_vec_start - 1;
+}
+
+/* dump accumulated "unified" diff changes */
+static void
+dump_unified_vec(FILE *f1, FILE *f2, int flags)
+{
+	struct context_vec *cvp = context_vec_start;
+	int lowa, upb, lowc, upd;
+	int a, b, c, d;
+	char ch, *f;
+
+	if (context_vec_start > context_vec_ptr)
+		return;
+
+	b = d = 0;		/* gcc */
+	lowa = MAXIMUM(1, cvp->a - diff_context);
+	upb = MINIMUM(len[0], context_vec_ptr->b + diff_context);
+	lowc = MAXIMUM(1, cvp->c - diff_context);
+	upd = MINIMUM(len[1], context_vec_ptr->d + diff_context);
+
+	diff_output("@@ -");
+	uni_range(lowa, upb);
+	diff_output(" +");
+	uni_range(lowc, upd);
+	diff_output(" @@");
+	if ((flags & D_PROTOTYPE)) {
+		f = match_function(ixold, lowa-1, f1);
+		if (f != NULL)
+			diff_output(" %s", f);
+	}
+	diff_output("\n");
+
+	/*
+	 * Output changes in "unified" diff format--the old and new lines
+	 * are printed together.
+	 */
+	for (; cvp <= context_vec_ptr; cvp++) {
+		a = cvp->a;
+		b = cvp->b;
+		c = cvp->c;
+		d = cvp->d;
+
+		/*
+		 * c: both new and old changes
+		 * d: only changes in the old file
+		 * a: only changes in the new file
+		 */
+		if (a <= b && c <= d)
+			ch = 'c';
+		else
+			ch = (a <= b) ? 'd' : 'a';
+
+		switch (ch) {
+		case 'c':
+			fetch(ixold, lowa, a - 1, f1, ' ', 0, flags);
+			fetch(ixold, a, b, f1, '-', 0, flags);
+			fetch(ixnew, c, d, f2, '+', 0, flags);
+			break;
+		case 'd':
+			fetch(ixold, lowa, a - 1, f1, ' ', 0, flags);
+			fetch(ixold, a, b, f1, '-', 0, flags);
+			break;
+		case 'a':
+			fetch(ixnew, lowc, c - 1, f2, ' ', 0, flags);
+			fetch(ixnew, c, d, f2, '+', 0, flags);
+			break;
+		}
+		lowa = b + 1;
+		lowc = d + 1;
+	}
+	fetch(ixnew, d + 1, upd, f2, ' ', 0, flags);
+
+	context_vec_ptr = context_vec_start - 1;
+}
+
+static void
+print_header(const char *file1, const char *file2)
+{
+	if (label[0] != NULL)
+		diff_output("%s %s\n", diff_format == D_CONTEXT ? "***" : "---",
+		    label[0]);
+	else
+		diff_output("%s %s\t%s", diff_format == D_CONTEXT ? "***" : "---",
+		    file1, ctime(&stb1.st_mtime));
+	if (label[1] != NULL)
+		diff_output("%s %s\n", diff_format == D_CONTEXT ? "---" : "+++",
+		    label[1]);
+	else
+		diff_output("%s %s\t%s", diff_format == D_CONTEXT ? "---" : "+++",
+		    file2, ctime(&stb2.st_mtime));
+}