Everhart, Glenn
From:	helbig@man.ac.uk
Sent:	Thursday, January 28, 1999 7:04 AM
To:	Info-VAX@Mvb.Saic.Com
Subject:	decode .rtf files on VMS
Thanks to the source code below (got from someone in this newsgroup a
while back) I can decode b64 encoded stuff.  However, sometimes what is
encoded is an RTF file, which I cannot read.  I seem to remember that
someone said there is a program for VMS which will convert RTF files to
a readable format.  (I just loaded this by-hand decoded file into WORD
on an NT PC (shudder, shudder) and it looked OK and printed out fine.)

Anyone know where I can get this?  Will it do just text or graphics as 
well?


--
Phillip Helbig                          Email ......... p.helbig@jb.man.ac.uk
Nuffield Radio Astronomy Laboratories   Tel. .... +44 1477 571 321 (ext. 297)
Jodrell Bank                            Fax ................ +44 1477 571 618
Macclesfield                            Telex ................ 36149 JODREL G
UK-Cheshire SK11 9DL                    Web ... http://www.jb.man.ac.uk/~pjh/

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

int decode_b64char( int ch )
{
    int  sextet;

         if( ('A' <= ch) && (ch <= 'Z') )  sextet = ch - 'A';
    else if( ('a' <= ch) && (ch <= 'z') )  sextet = (ch - 'a') + 26;
    else if( ('0' <= ch) && (ch <= '9') )  sextet = (ch - '0') + 52;
    else if( ch == '+' )                   sextet = 62;
    else if( ch == '/' )                   sextet = 63;
    else {
        fprintf( stderr, (isprint(ch) ? "Illegal base64 character '%c'\n" :
                                        "Illegal base64 character 0x%02x\n"),
                 ch );
        exit( EXIT_FAILURE );
    }
    return( sextet );
}


main( int argc, char *argv[] )
{
    FILE *fin;
    FILE *fout;
    int  flushing = 0;
    int  temp = 0;
    int  bits = 0;
    int  ch;

    if( argc < 2 ) {
        fprintf( stderr, "Usage: b64decode <infile> [outfile]\n" );
        exit( EXIT_SUCCESS );
    }

    fin = fopen( argv[1], "r" );
    if( fin == NULL ) {
        perror( "openin" );
        exit( EXIT_FAILURE );
    }

    if( argc < 3 )
        fout = stdout;
    else {
        fout = fopen( argv[2], "wb" );
        if( fout == NULL ) {
            perror( "openout" );
            fclose( fin );
            exit( EXIT_FAILURE );
        }
    }

    while( (ch = fgetc( fin )) != EOF ) {
        if( isspace(ch) )
            continue;

        if( flushing ) {
            if( ch != '=' ) {
                fprintf( stderr, "Illegal character in EOF padding\n" );
                exit( EXIT_FAILURE );
            }
        }
        else {
            if( ch == '=' )
                flushing = 1;
            else {
                temp <<= 6;
                temp |= decode_b64char( ch );
                bits += 6;
                if( bits >= 8 ) {
                    bits -= 8;
                    fputc( (0xff & (temp >> bits)), fout );
                }
            }
        }
    }

    fclose( fout );
    fclose( fin );
}

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