usr/src/local/local.cmd/chgbars.c

/*
 * Copyright (c) 1987 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef lint
static char sccsid[] = "@(#)chgbars.c   5.1 (Berkeley) %G%";
#endif not lint

/*
 * Derived from original program by A. Dain Samples.
 *
 * The program chgbars will accept the output from a diff comparison of
 * two versions of a file.  It will then read the new version of the file
 * and insert the appropriate troff commands to put change bars in the
 * right margin. Typing 'chgbars' without any arguments will give you
 * some documentation and an example.
 *
 * Caveat: If you make a change inside an equation or table, the
 * preprocessors eqn and tbl may not like what chgbars does to the file.
 * You may have to go into the output from chgbars to remove or rearrange
 * some of the lines of the form '.mc |  \"open' or '.mc  \"close' in
 * order to get through tbl or eqn.
 *
 * Unfortunately, users of RCS will be disappointed: one cannot use rcsdiff.
 * Rcsdiff compares the files in the wrong order.
 *
 * There is a relatively easy way to do the job with the tools sed and awk.
 * However, sed does not allow enough commands to process large documents.
 * In the true spirit of a filter/tool, chgbars is limited only by the
 * amount of memory on the machine, and is fast and useful.
 *
 * The modifications necessary are outlined:
 *
 * FORM OF DIFF OUTPUT  COMMENT                 NEW SED COMMANDS
 * ================================================================
 * 100a                 means those lines       100a\\
 * L1                   were deleted from       .mc |\\
 * L2                   oldfile                 .mc
 * :
 * Ln
 * .
 * ----------------------------------------------------------------
 * 100c
 * L1
 * L2
 * :
 * Ln
 * .
 *      means that line 100 in newfile replaced all those lines in oldfile.
 *              100a
 *              .mc
 *              99 a
 *              .mc |
 * ----------------------------------------------------------------
 * 100d                 that line was added     100a\\
 *                      to oldfile              .mc
 *                                              99a\\
 *                                              .mc |
 * ----------------------------------------------------------------
 * 100,200d             those lines were        200a\\
 *                      added to oldfile                .mc
 *                                              99a\\
 *                                              .mc |
 * ----------------------------------------------------------------
 * 100,200c
 * L1
 * L2
 * :
 * Ln
 * .
 *      means lines 100 to 200 of newfile replaced all the following lines
 *      in oldfile.
 *              200a
 *              .mc
 *              99a
 *              .mc |
 * ----------------------------------------------------------------
 */

#include <stdio.h>
#include <strings.h>
#include <ctype.h>

#define dbg(s)  /* fprintf(stderr,"s\n") */
#define none 0
#define open 1
#define close 2
#define both 3

char (*action)[];
FILE *file1, *file2;
char linebuf[1024];
char nextch;
int num1, num2, t, line;
char lineact;

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1986 Regents of the University of California.\n\
 All rights reserved.\n";
#endif not lint

main(argc, argv)
        int argc;
        char *argv[];
{
        register char  *p;
        register int    i;

        if (argc < 2)
                usage();
        /* open $1 */
        if (strcmp(argv[1], "-") == 0) {
                file1 = stdin;
                if (argc <= 2)
                        usage();
        } else if ((file1 = fopen(argv[1], "r")) == NULL) {
                fprintf(stderr, "error: can't open %s\n", argv[1]);
                exit(1);
        }
        /*
         * read each entry setting the appropriate entry in action[]
         *
         * get the first line number: since diff -e puts the numbers out
         * in reverse order, this tells us how big to make the file
         */
        readline();
        if (lineact == 'a')
                t = num1;
        else
                t = num2;
        action = (char (*)[]) malloc(t + 1);
        for (p = (char *) action, i = 0; i < t; i++)
                *p++ = (char) none;
        while (!feof(file1)) {
                if (lineact == 'a') {
                        (*action)[num1] = both;
                        skiptilldot();
                } else {
                        (*action)[num1 - 1] = open;
                        (*action)[num2] = close;
                        if (lineact == 'c')
                                skiptilldot();
                        else
                                skiptilleol();
                }
                readline();
        }
        fclose(file1);
        /* open $2 */
        if (argc == 2)
                file2 = stdin;
        else
                file2 = fopen(argv[2], "r");
        if (file2 == NULL) {
                fprintf(stderr, "can't open %2\n", argv[2]);
                exit(1);
        }
        line = 0;
        while (!feof(file2)) {
                if (line != 0)
                        fputs(linebuf, stdout);
                if (line <= t) {
                        switch ((*action)[line]) {
                        case open:
                                printf(".mc |   \\\"open\n");
                                break;
                        case close:
                                printf(".mc     \\\"close\n");
                                break;
                        case both:
                                printf(".mc |   \\\"both\n");
                                printf(".mc\n");
                                break;
                        default:;
                        }
                }
                fgets(linebuf, sizeof(linebuf), file2);
                line++;
        }
        if (line <= t) {
                fprintf(stderr, "oops: number of lines read does not match\n");
                fprintf(stderr, "number of lines expected\n");
                exit(1);
        }
        exit(0);
}

usage()
{

        fprintf(stderr, "Usage:\n");
        fprintf(stderr, "\tchgbars diff.out\n");
        fprintf(stderr, "\t\t\treads the output from diff, and expects the\n");
        fprintf(stderr, "\t\t\tfile to be modified on stdin\n");
        fprintf(stderr, "\tchgbars diff.out file.tbm\n");
        fprintf(stderr, "\t\t\tboth the output from diff and the file to be\n");
        fprintf(stderr, "\t\t\tmodified are stated explicitly\n");
        fprintf(stderr, "\tchgbars - file.tbm\n");
        fprintf(stderr, "\t\t\treads the output from diff on stdin\n");
        fprintf(stderr, "\nE.g.\n");
        fprintf(stderr, "diff -b -e newfile oldfile | chgbars - newfile | vtroff -ms\n");
        fprintf(stderr, "\t(note the order of the files in the diff command!)\n");
        fprintf(stderr, "\n\nBe forewarned: chgbars does not know about tables or equations.\n");
        fprintf(stderr, "If any part of a table or equation is changed, chgbars will insert the\n");
        fprintf(stderr, ".mc commands, whether tbl or eqn likes it or not.\n");
        fprintf(stderr, "This means that you may have to do some hand editing of the output of\n");
        fprintf(stderr, "chgbars to make it acceptable to one or both of these preprocessors.\n");

        exit(1);
}

readnum()
{
        int num;

        dbg(readnum);
        num = 0;
        nextch = getc(file1);
        while (isdigit(nextch)) {
                num = num * 10 + nextch - '0';
                nextch = getc(file1);
        }
        return num;
}

readline()
{

        dbg(readline);
        num1 = readnum();
        if (nextch == ',')
                num2 = readnum();
        else
                num2 = num1;
        lineact = nextch;
}

skiptilleol()
{

        dbg(skiptilleol);
        while (nextch != '\n')
                nextch = getc(file1);
}

skiptilldot()
{

        dbg(skiptilldot);
        do {
                if (fgets(linebuf, sizeof(linebuf), file1) == NULL) {
                        fprintf(stderr, "error reading file1\n");
                        exit(1);
                }
        } while (strcmp(linebuf, ".\n") != 0);
}