QBasic & Borland Pascal & C/Delphi5.iso/C/Samples/CRCDOS.ARJ/CRCDOS.C

C/C++ Source or Header | 1988-01-12 | 5.3 KB | 198 lines

/*********************************************************************/
/* Module name: crcdos.c                                             */
/* Date: 11 Jan 88                                                   */
/* Environment: Turbo C 1.0                                          */
/* Author: R. E. Faith                                               */
/* Notice: Public Domain: The following conditions apply to use:     */
/*         1) No fee shall be charged for distribution.              */
/*         2) Modifications may be made, but authorship information  */
/*            for all contributing authors shall be retained.        */
/*         3) This code may not be included as part of a commercial  */
/*            package.                                               */
/* This program is provided AS IS without any warranty, expressed or */
/* implied, including, but not limited to, fitness for a particular  */
/* purpose.                                                          */
/*********************************************************************/
static char    *__ATH__ = "@(#)Public domain (P) 1988, R. E. Faith";
static char    *__VER__ = "@(#)crcdos: version 1.0, 11 Jan 88";

#include <stdio.h>
#include <stdlib.h>
#include <dos.h>
#include <string.h>
#include <dir.h>
#include <genlib.h>

#define BUF_SIZE    0x2800
static char        buffer[BUF_SIZE];
#define DO_16        1        /* otherwise, do crc ccitt style */
static int        Build = 0, Compare = 0, Silent = 0;

static void usage( void )
{
    fprintf( stderr, "%s\n", &__VER__[4] );
    fprintf( stderr, "%s\n\n", &__ATH__[4] );
    fprintf( stderr,
        "usage: crcdos [-s] [-b crc_file list_file] [-c crc_file]\n" );
    fprintf( stderr, "-s: be silent when comparing files\n" );
    fprintf( stderr, "-b: build a good crc file\n" );
    fprintf( stderr, "-c: compare current crc's to file\n" );
    exit( 1 );
}

static WORD get_crc( char *filename )
{
    register FILE    *str;
    register int    size;
    register WORD    crc = 0;

    if ( (str = fopen( filename, "rb" )) == NULL ) {
        fprintf( stderr, "crcdos: cannot open %s for read",
            fntounix( filename ) );
        perror( "" );
        return 0;
    }

    while ( (size = fread( buffer, 1, BUF_SIZE, str )) != 0 ) {
#ifdef DO_16
            crc = get_crc_16( crc, buffer, size );
#else
            crc = get_crc_ccitt( crc, buffer, size );
#endif
    }

    fclose( str );

    return crc;
}

static void build( char *target, char *infile )
{
    char        path[MAXPATH];
    register FILE    *str, *instr;
    register WORD    crc;

    if ( (instr = fopen( infile, "r" )) == NULL) {
        fprintf( stderr, "crcdos: cannot open %s for read",
            fntounix( infile ) );
        perror( "" );
        exit( 1 );
    }

    if ( (str = fopen( target, "w" )) == NULL ) {
        fprintf( stderr, "crcdos: cannot open %s for write",
            fntounix( target ) );
        perror( "" );
        exit( 1 );
    }

    while (fgets( path, MAXPATH, instr )) {
        fntomsdos( path );
        crc = get_crc( path );
        printf( "%s: crc = %04x\n", path, crc );
        fprintf( str, "%s %04x\n", path, crc );
    }

    fclose( str );
    fclose( instr );
}

static void compare( char *filename )
{
    char        path[MAXPATH];
    register FILE    *str;
    register WORD    newcrc;
    WORD        oldcrc;

    if ( (str = fopen( filename, "r" )) == NULL ) {
        fprintf( stderr, "crcdos: cannot open %s for write",
            fntounix( filename ) );
        perror( "" );
        exit( 1 );
    }

    while (fscanf( str, "%s %x", path, &oldcrc ) != EOF) {
        fntomsdos( path );
        newcrc = get_crc( path );
        if (!Silent)
            printf( "%s: oldcrc = %04x, newcrc = %04x\n",
                path, oldcrc, newcrc );
        if (newcrc != oldcrc) {
            printf( "\n*** WARNING: %s has been altered! *******\n",
                path );
            printf( "*** The crc of %s was %04x and now is %04x\n",
                path, oldcrc, newcrc );
printf( "*** If there is no reason for this change, a virus could have\n");
printf( "*** infected the file!  Consider replacing this file with a\n" );
printf( "*** sterile backup copy.  Please realize that some files are\n" );
printf( "*** designed to be self-modifying: this is only a warning.\n\n" );
        }
    }

    fclose( str );

}

main( int argc, char **argv )
{
    int        ch;
    char        target[MAXPATH], infile[MAXPATH];

    if (_osmajor < 2) {
        fprintf( stderr, "Requires DOS 2.x or greater!\n" );
        exit( 1 );
    }

    harderr( chandler );
    ctrlbrk( c_break );

    opterr = 0;    /* Don't let getopt() report errors */
    while ((ch = getopt( argc, argv, "sb:c:" )) != EOF)
        switch (ch) {
        case 's': Silent = !Silent; break;
        case 'b':
            Build = 1;
            strcpy( target, optarg );
            fntomsdos( target );
            break;
        case 'c':
            Compare = 1;
            strcpy( target, optarg );
            fntomsdos( target );
            break;
        default:
            usage();
        }

    if (Build && Compare) {
        usage();
        exit( 0 );
    }

    if (Build) {
        if (optind >= argc)
            usage();
        strcpy( infile, argv[optind] );
        fntomsdos( infile );
        printf( "Building a list of valid crc's from the list in %s\n",
            infile );
        build( target, infile );
        printf( "The crc list has been stored in %s\n", target );
        printf( "To check the crc's, use:\n" );
        printf( "    crcdos -c %s      or\n", target );
        printf( "    crcdos -sc %s     (for silent checking)\n",
            target );
        exit( 0 );
    }

    if (Compare) {
        if (!Silent)
            printf( "Comparing crc's with the list in %s\n",
                target );
        compare( target );
        exit( 0 );
    }

    usage();
}