cmd/diff/diffh.c

	diffh.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2004 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 <ctype.h>
#include <locale.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <limits.h>
#include <stdarg.h>

#define C       3
#define RANGE       30
#define LEN     255
#define INF     16384

char *text[2][RANGE];
long lineno[2] = {1, 1};    /* no. of 1st stored line in each file */
int ntext[2];       /* number of stored lines in each */
long n0, n1;        /* scan pointer in each */
int bflag;
int debug = 0;
FILE *file[2];
static int diffFound = 0;

static char *getl(int f, long n);
static void clrl(int f, long n);
static void movstr(char *s, char *t);
static int easysynch(void);
static int output(int a, int b);
static void change(long a, int b, long c, int d, char *s);
static void range(long a, int b);
static int cmp(char *s, char *t);
static FILE *dopen(char *f1, char *f2);
static void progerr(char *s);
static void error(char *err, ...);
static int hardsynch(void);

    /* return pointer to line n of file f */
static char *
getl(int f, long n)
{
    char *t;
    int delta, nt;

again:
    delta = n - lineno[f];
    nt = ntext[f];
    if (delta < 0)
        progerr("1");
    if (delta < nt)
        return (text[f][delta]);
    if (delta > nt)
        progerr("2");
    if (nt >= RANGE)
        progerr("3");
    if (feof(file[f]))
        return (NULL);
    t = text[f][nt];
    if (t == 0) {
        t = text[f][nt] = (char *)malloc(LEN+1);
        if (t == NULL)
            if (hardsynch())
                goto again;
            else
                progerr("5");
    }
    t = fgets(t, LEN, file[f]);
    if (t != NULL)
        ntext[f]++;
    return (t);
}

    /* remove thru line n of file f from storage */
static void
clrl(int f, long n)
{
    int i, j;

    j = n-lineno[f]+1;
    for (i = 0; i+j < ntext[f]; i++)
        movstr(text[f][i+j], text[f][i]);
    lineno[f] = n+1;
    ntext[f] -= j;
}

static void
movstr(char *s, char *t)
{
    while (*t++ = *s++)
        continue;
}

int
main(int argc, char **argv)
{
    char *s0, *s1;

    if ((argc > 1) && (*argv[1] == '-')) {
        argc--;
        argv++;
        while (*++argv[0])
            if (*argv[0] == 'b')
                bflag++;
    }

    (void) setlocale(LC_ALL, "");
#if !defined(TEXT_DOMAIN)       /* Should be defined by cc -D */
#define TEXT_DOMAIN "SYS_TEST"  /* Use this only if it weren't */
#endif
    (void) textdomain(TEXT_DOMAIN);

    if (argc != 3)
        error(gettext("must have 2 file arguments"));
    file[0] = dopen(argv[1], argv[2]);
    file[1] = dopen(argv[2], argv[1]);
    for (;;) {
        s0 = getl(0, ++n0);
        s1 = getl(1, ++n1);
        if (s0 == NULL || s1 == NULL)
            break;
        if (cmp(s0, s1) != 0) {
            if (!easysynch() && !hardsynch())
                progerr("5");
        } else {
            clrl(0, n0);
            clrl(1, n1);
        }
    }
    /* diff is expected to return 1 if the files differ */
    if (s0 == NULL && s1 == NULL)
        return (diffFound);
    if (s0 == NULL) {
        (void) output(-1, INF);
        return (1);
    }
    if (s1 == NULL) {
        (void) output(INF, -1);
        return (1);
    }
    /* NOTREACHED */
}

    /* synch on C successive matches */
static int
easysynch()
{
    int i, j;
    int k, m;
    char *s0, *s1;

    for (i = j = 1; i < RANGE && j < RANGE; i++, j++) {
        s0 = getl(0, n0+i);
        if (s0 == NULL)
            return (output(INF, INF));
        for (k = C-1; k < j; k++) {
            for (m = 0; m < C; m++)
                if (cmp(getl(0, n0+i-m),
                    getl(1, n1+k-m)) != 0)
                    goto cont1;
            return (output(i-C, k-C));
cont1:
            ;
        }
        s1 = getl(1, n1+j);
        if (s1 == NULL)
            return (output(INF, INF));
        for (k = C-1; k <= i; k++) {
            for (m = 0; m < C; m++)
                if (cmp(getl(0, n0+k-m),
                    getl(1, n1+j-m)) != 0)
                    goto cont2;
            return (output(k-C, j-C));
cont2:
            ;
        }
    }
    return (0);
}

static int
output(int a, int b)
{
    int i;
    char *s;

    if (a < 0)
        change(n0-1, 0, n1, b, "a");
    else if (b < 0)
        change(n0, a, n1-1, 0, "d");
    else
        change(n0, a, n1, b, "c");
    for (i = 0; i <= a; i++) {
        s = getl(0, n0+i);
        if (s == NULL)
            break;
        (void) printf("< %s", s);
        clrl(0, n0+i);
    }
    n0 += i-1;
    if (a >= 0 && b >= 0)
        (void) printf("---\n");
    for (i = 0; i <= b; i++) {
        s = getl(1, n1+i);
        if (s == NULL)
            break;
        (void) printf("> %s", s);
        clrl(1, n1+i);
    }
    diffFound = 1;
    n1 += i-1;
    return (1);
}

static void
change(long a, int b, long c, int d, char *s)
{
    range(a, b);
    (void) printf("%s", s);
    range(c, d);
    (void) printf("\n");
}

static void
range(long a, int b)
{
    if (b == INF)
        (void) printf("%ld,$", a);
    else if (b == 0)
        (void) printf("%ld", a);
    else
        (void) printf("%ld,%ld", a, a+b);
}

static int
cmp(char *s, char *t)
{
    if (debug)
        (void) printf("%s:%s\n", s, t);
    for (;;) {
        if (bflag && isspace(*s) && isspace(*t)) {
            while (isspace(*++s))
                ;
            while (isspace(*++t))
                ;
        }
        if (*s != *t || *s == 0)
            break;
        s++;
        t++;
    }
    return (*s-*t);
}

static FILE *
dopen(char *f1, char *f2)
{
    FILE *f;
    char b[PATH_MAX], *bptr, *eptr;
    struct stat statbuf;

    if (cmp(f1, "-") == 0) {
        if (cmp(f2, "-") == 0)
            error(gettext("can't do - -"));
        else {
            if (fstat(fileno(stdin), &statbuf) == -1)
                error(gettext("can't access stdin"));
            else
                return (stdin);
        }
    }
    if (stat(f1, &statbuf) == -1)
        error(gettext("can't access %s"), f1);
    if ((statbuf.st_mode & S_IFMT) == S_IFDIR) {
        for (bptr = b; *bptr = *f1++; bptr++)
            ;
        *bptr++ = '/';
        for (eptr = f2; *eptr; eptr++)
            if (*eptr == '/' && eptr[1] != 0 && eptr[1] != '/')
                f2 = eptr+1;
        while (*bptr++ = *f2++)
            ;
        f1 = b;
    }
    f = fopen(f1, "r");
    if (f == NULL)
        error(gettext("can't open %s"), f1);
    return (f);
}


static void
progerr(char *s)
{
    error(gettext("program error %s"), s);
}

static void
error(char *err, ...)
{
    va_list ap;

    va_start(ap, err);
    (void) fprintf(stderr, "diffh: ");
    (void) vfprintf(stderr, err, ap);
    (void) fprintf(stderr, "\n");
    va_end(ap);
    exit(2);
}

    /* stub for resychronization beyond limits of text buf */
static int
hardsynch()
{
    change(n0, INF, n1, INF, "c");
    (void) printf(gettext("---change record omitted\n"));
    error(gettext("can't resynchronize"));
    return (0);
}