OpenSolaris_b135/cmd/diff3/diff3prog.c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <sys/param.h>
#include <errno.h>
#
/*
* diff3 - 3-way differential file comparison
*/
/*
* 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).
*/
struct range {int from, to; };
/*
* from is first in range of changed lines
* to is last+1
* from = to = line after point of insertion
* for added lines
*/
struct diff {struct range old, new; };
#define NC 4096
/*
* de is used to gather editing scripts,
* that 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(!?)
*/
static struct diff d13[NC];
static struct diff d23[NC];
/*
* array overlap indicates which sections in de correspond to
* lines that are different in all three files.
*/
static struct diff de[NC];
static char overlap[NC];
static int overlapcnt = 0;
static char line[LINE_MAX+1];
static FILE *fp[3];
/*
* the number of the last-read line in each file
* is kept in cline[0-2]
*/
static int cline[3];
/*
* the latest known correspondence between line
* numbers of the 3 files is stored in last[1-3]
*/
static int last[4];
static int eflag;
static int oflag; /* indicates whether to mark overlaps (-E or -X) */
static int debug = 0;
/* markers for -E and -X: */
static char f1mark[8+MAXPATHLEN], f3mark[8+MAXPATHLEN];
/* Need space for "<<<<<<< " or ">>>>>>> " plus filename */
static int save_err; /* saves errno */
static int readin(char *name, struct diff *dd);
static int number(char **lc);
static int digit(int c);
static int getchange(FILE *b);
static int getline(FILE *b);
static void merge(int m1, int m2);
static void separate(char *s);
static void change(int i, struct range *rold, int dup);
static void prange(struct range *rold);
static void keep(int i, struct range *rnew);
static int skip(int i, int from, char *pr);
static int duplicate(struct range *r1, struct range *r2);
static void repos(int nchar);
static void trouble();
static int edit(struct diff *diff, int dup, int j);
static void edscript(int n);
static void usage();
int
main(int argc, char **argv)
{
int i, m, n;
eflag = 0;
oflag = 0;
if ((argc > 1) && (*argv[1] == '-')) {
switch (argv[1][1]) {
case 'e':
eflag = 3;
break;
case '3':
eflag = 2;
break;
case 'x':
eflag = 1;
break;
case 'E':
eflag = 3;
oflag = 1;
break;
case 'X':
oflag = eflag = 1;
break;
default:
usage();
break;
}
argv++;
argc--;
}
if (argc < 6)
usage();
if (oflag) {
(void) snprintf(f1mark, sizeof (f1mark), "<<<<<<< %s",
argc >= 7 ? argv[6] : argv[3]);
(void) snprintf(f3mark, sizeof (f3mark), ">>>>>>> %s",
argc >= 8 ? argv[7] : argv[5]);
}
m = readin(argv[1], d13);
n = readin(argv[2], d23);
for (i = 0; i <= 2; i++)
if ((fp[i] = fopen(argv[i+3], "r")) == NULL) {
save_err = errno;
(void) fprintf(stderr, "diff3: can't open %s: ",
argv[i+3]);
errno = save_err;
perror("");
exit(1);
}
merge(m, n);
return (0);
}
/*
* 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)
*/
static int
readin(char *name, struct diff *dd)
{
int i;
int a, b, c, d;
char kind;
char *p;
if ((fp[0] = fopen(name, "r")) == NULL) {
save_err = errno;
(void) fprintf(stderr, "diff3: can't open %s: ", name);
errno = save_err;
perror("");
exit(1);
}
for (i = 0; getchange(fp[0]); i++) {
if (i >= NC) {
(void) fprintf(stderr, "diff3: too many changes\n");
exit(0);
}
p = line;
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;
}
dd[i].old.from = dd[i-1].old.to;
dd[i].new.from = dd[i-1].new.to;
(void) fclose(fp[0]);
return (i);
}
static int
number(char **lc)
{
int nn;
nn = 0;
while (digit(**lc))
nn = nn*10 + *(*lc)++ - '0';
return (nn);
}
static int
digit(int c)
{
return (c >= '0' && c <= '9');
}
static int
getchange(FILE *b)
{
while (getline(b))
if (digit(line[0]))
return (1);
return (0);
}
static int
getline(FILE *b)
{
int i, c;
for (i = 0; i < sizeof (line)-1; i++) {
c = getc(b);
if (c == EOF) {
line[i] = 0;
return (i);
}
line[i] = c;
if (c == '\n') {
line[++i] = 0;
return (i);
}
}
return (0);
}
static void
merge(int m1, int m2)
{
struct diff *d1, *d2, *d3;
int dup;
int j;
int t1, t2;
d1 = d13;
d2 = d23;
j = 0;
for (; (t1 = d1 < d13+m1) | (t2 = d2 < d23+m2); ) {
if (debug) {
(void) 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) {
dup = duplicate(&d1->old, &d2->old);
/*
* dup = 0 means all files differ
* dup = 1 meands files 1&2 identical
*/
if (eflag == 0) {
separate(dup?"3":"");
change(1, &d1->old, dup);
change(2, &d2->old, 0);
d3 = d1->old.to > d1->old.from ? d1 : d2;
change(3, &d3->new, 0);
} else
j = edit(d1, dup, j);
d1++;
d2++;
continue;
}
/*
* overlapping changes from file1 & 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;
}
}
if (eflag) {
edscript(j);
if (j)
(void) printf("w\nq\n");
}
}
static void
separate(char *s)
{
(void) printf("====%s\n", s);
}
/*
* the range of ines 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
*/
static void
change(int i, struct range *rold, int dup)
{
(void) printf("%d:", i);
last[i] = rold->to;
prange(rold);
if (dup)
return;
if (debug)
return;
i--;
(void) skip(i, rold->from, (char *)0);
(void) skip(i, rold->to, " ");
}
/*
* print the range of line numbers, rold.from thru rold.to
* as n1, n2 or n1
*/
static void
prange(struct range *rold)
{
if (rold->to <= rold->from)
(void) printf("%da\n", rold->from-1);
else {
(void) printf("%d", rold->from);
if (rold->to > rold->from+1)
(void) printf(",%d", rold->to-1);
(void) printf("c\n");
}
}
/*
* 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
*/
static void
keep(int i, struct range *rnew)
{
int delta;
struct range trange;
delta = last[3] - last[i];
trange.from = rnew->from - delta;
trange.to = rnew->to - delta;
change(i, &trange, 1);
}
/*
* skip to just befor line number from in file i
* if "pr" is nonzero, print all skipped stuff
* with string pr as a prefix
*/
static int
skip(int i, int from, char *pr)
{
int j, n;
for (n = 0; cline[i] < from-1; n += j) {
if ((j = getline(fp[i])) == 0)
trouble();
if (pr)
(void) printf("%s%s", pr, line);
cline[i]++;
}
return (n);
}
/*
* return 1 or 0 according as the old range
* (in file 1) contains exactly the same data
* as the new range (in file 2)
*/
static int
duplicate(struct range *r1, struct range *r2)
{
int c, d;
int nchar;
int nline;
if (r1->to-r1->from != r2->to-r2->from)
return (0);
(void) skip(0, r1->from, (char *)0);
(void) skip(1, r2->from, (char *)0);
nchar = 0;
for (nline = 0; nline < r1->to-r1->from; nline++) {
do {
c = getc(fp[0]);
d = getc(fp[1]);
if (c == -1 || d == -1)
trouble();
nchar++;
if (c != d) {
repos(nchar);
return (0);
}
} while (c != '\n');
}
repos(nchar);
return (1);
}
static void
repos(int nchar)
{
int i;
for (i = 0; i < 2; i++)
(void) fseek(fp[i], (long)-nchar, 1);
}
static void
trouble()
{
(void) fprintf(stderr, "diff3: logic error\n");
abort();
}
/*
* collect an editing script for later regurgitation
*/
static int
edit(struct diff *diff, int dup, int j)
{
if (((dup+1)&eflag) == 0)
return (j);
j++;
overlap[j] = !dup;
if (!dup) 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, (char *)0);
de[j].new.to = de[j].new.from + skip(2, diff->new.to, (char *)0);
return (j);
}
/* regurgitate */
static void
edscript(int n)
{
int j, k;
char block[BUFSIZ];
for (n = n; n > 0; n--) {
if (!oflag || !overlap[n])
prange(&de[n].old);
else
(void) printf("%da\n=======\n", de[n].old.to -1);
(void) fseek(fp[2], (long)de[n].new.from, 0);
for (k = de[n].new.to-de[n].new.from; k > 0; k -= j) {
j = k > BUFSIZ?BUFSIZ:k;
if (fread(block, 1, j, fp[2]) != j)
trouble();
(void) fwrite(block, 1, j, stdout);
}
if (!oflag || !overlap[n])
(void) printf(".\n");
else {
(void) printf("%s\n.\n", f3mark);
(void) printf("%da\n%s\n.\n", de[n].old.from-1, f1mark);
}
}
}
static void
usage()
{
(void) fprintf(stderr,
"\tusage: diff3prog [-ex3EX] d13 d23 f1 f2 f3 [m1 m2]\n");
exit(1);
}