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1.1
date	2013.01.13.22.17.22;	author agc;	state Exp;
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desc
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1.1
log
@Add wdiff functionality, which performs a word-by-word comparison
between two areas of memory, or between two files.  This is
accomplished using two new functions, wdiff_mem() or wdiff_file(), and
results can either be retrieved by displaying them to stdout, to an
output file, or by using diff_get_diffs() to retrieve the results
in-memory.

Internally, the two files/areas of memory are split into separate
areas of memory with a word on each line, and the two areas of memory
are compared using diff_mem().

Comparisons can also be made in a case-insensitive manner.

In the comparison output, added text is displayed in {+ ...  +}
delimiters, and deleted text is shown with [- ... -] delimiters.
Changes are displayed as a deletion and an addition.

+ Deleted text can be inhibited from display by using the -1 argument
  to netwdiff(1).
+ Added text can be inhibited from display by using the -2 argument to
  netwdiff(1).
+ Common text can be inhibited from display by using the -3 argument
  to netwdiff(1).

(Don't blame me, these flags are the ones used by GNU wdiff.)

With thanks to Thomas Klausner for the nudge to create this.
@
text
@/*-
 * Copyright (c) 2013 Alistair Crooks <agc@@NetBSD.org>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>

#include <err.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

typedef struct f_t {
	char	*name;
	char	*mapped;
	FILE	*fp;
	size_t	 size;
} f_t;

static int
finit(f_t *file, const char *name)
{
	struct stat	st;

	memset(file, 0x0, sizeof(*file));
	if ((file->fp = fopen(name, "r")) == NULL) {
		return 0;
	}
	fstat(fileno(file->fp), &st);
	file->size = st.st_size;
	file->mapped = mmap(NULL, file->size, PROT_READ, MAP_SHARED, fileno(file->fp), 0);
	if (file->mapped == MAP_FAILED) {
		return 0;
	}
	file->name = strdup(name);
	return 1;
}

static void
fend(f_t *f)
{
	free(f->name);
	munmap(f->mapped, f->size);
	fclose(f->fp);
	memset(f, 0x0, sizeof(*f));
}

static int
difffile(const char *filename1, const char *filename2)
{
	FILE	*pp;
	char	 buf[2048]; // XXX
	char	 cmd[2048]; // XXX
	f_t	 f[2];

	finit(&f[0], filename1);
	finit(&f[1], filename2);
	snprintf(cmd, sizeof(cmd), "diff %s %s", filename1, filename2);
	if ((pp = popen(cmd, "r")) == NULL) {
		return 0;
	}
	while (fgets(buf, sizeof(buf), pp) != NULL) {
		printf("%s", buf);
	}
	pclose(pp);
	fend(&f[0]);
	fend(&f[1]);
	return 1;
}

/*
a long and interesting comment.

multiple lines.

very informative
*/

int
main(int argc, char **argv)
{
	int	i;

	while ((i = getopt(argc, argv, "")) != -1) {
	}
	if (argc - optind < 2) {
		errx(EXIT_FAILURE, "Usage: agcdiff file1 file2");
	}
	difffile(argv[optind], argv[optind + 1]);
	exit(EXIT_SUCCESS);
}
@