Ham Radio 2000 #1/Ham Radio 2000.iso/ham2000/packet/p_tapr/tnchst/ax25.c

C/C++ Source or Header | 1990-06-04 | 4.3 KB | 195 lines

/*** display function for aft test ****/

#define   AX25_ADDRLEN   7


void moncall( callptr )
byte *callptr;
{
    int x;


    /* display callsign */

     for ( x = 0 ; x < AX25_ADDRLEN-1 ; ++x )
        printf("%c", (*callptr++) >> 1 );
}

void monframe( ptr, len )
byte *ptr;            /* points to 1st byte of aft frame */
int len;            /* length */
{
    putchar('\n');
    moncall( ptr+AX25_ADDRLEN );    /* source call */
    putchar('>');
    moncall( ptr );        /* dest */
    len -= (AX25_ADDRLEN * 2);
    ptr += (AX25_ADDRLEN * 2);

    while ( (*(ptr-1) & 1) == 0 &&    /* do while all calls not displayed */
        len > 0 )        /* and length is gt 0 in case not
                       ax25 */
     {
        moncall( ptr ) ;    /* display a callsign */
        putchar(',');
        ptr += AX25_ADDRLEN ;        /* point to next callsign */
        len -= AX25_ADDRLEN;
    };
    putchar(':');

    /** pointer is now pointing to cmd byte **/
    if ( *ptr == 03 || (*ptr & 1) == 0 )    /** if unproto or info **/
    {
        len -= 2 ;            /** adj len for cmd & pid **/
        ptr += 2 ;
        while ( len-- > 0 )        /** while chars to display **/
        {
            if (*ptr == 0x0d )
                putchar('\n');    /* map cr's to newlines */
            else
                putchar( *ptr );    /** print !cr's **/
            ++ptr;
        }
    }
    else /* else not data packet */
        printf("cmd: %02X",*ptr);

    putchar('\n');

}



/**** aux routines from loh ****/
makupper(c)
char *c;
{
    *c = toupper( *c );
}


iswhite( c )
char c;
{
    static word result ;

    switch ( c )
    {
        case ' ':
        case ',':
        case '\n':
        case '\r':
        case NULL:
            result = TRUE  ; break ;
        default:
            result = FALSE ;
    }
    return result ;
}

byte *atocall( buffer , chr )/* converts text callsign pointed to and returns
               pointer to char AFTER last ssid char if
               call was okay */
byte    *buffer;
char    *chr;
{
    int    is_ok ;
        /* set to FALSE when bad call character encountered */
    int    len   ;    /* # chars allowed in "text" portion */
    char    *wk   ; /* work pointer */
    int    ssid  ; /* hold ssid here when it is called for */

    is_ok = TRUE ;    /* assume okay */
    len   = AX25_ADDRLEN - 1 ;    /* init with # of characters allowed*/

    wk = buffer ;        /* set up build ptr */

    while (is_ok && *chr && len)/* while more chars to cvt & len valid */
    {
     if ( *chr == '-' || iswhite( *chr ) )
        break ;            /*white space or hyphen here?*/

     makupper( chr );

     if (   *chr >= 'A' && *chr <='Z' || isdigit( *chr ) )
                 /* if valid */
     {
        *wk++ = *chr++ << 1 ;        /* move call */
     }
     else            /* else not valid char */
        is_ok = FALSE ;    /* turn bad flag on */
     end_if
     --len ;    /* count a shifted character */
    } /*endwhile*/

    if ( !is_ok || len == AX25_ADDRLEN - 1 )
            /* if not ok or nothing converted or 6 chars cnvtd */
        return  FALSE     ;    /* return if was bad */

    /* else valid up till now, perhaps there is also an
       ssid.  first get the ssid (if any), then pad the
       built callsign if that is needed */

    ssid = 0x60 ;    /* assume null ssid */
      switch ( *chr++ )    /* if hyphen indicates ssid then */
      { case '-':
        if ( !isdigit( *chr ) )
            is_ok = FALSE ;
        else
        {
              ssid = *chr++ & 15 ; /*** 0-9 ssid only!! ***/
            if ( isdigit( *chr ) )
            {
                ssid *= 10 ;
                ssid += *chr++ & 15 ;
            }
            is_ok = ( ssid <<= 1 ) < 32 ;    /* validate ssid */
            ssid |= 0x60 ;
        }
          break;
        case NULL:
        --chr; break;
        default:
        if ( !iswhite( *--chr ) )    /* garbage here after call */
            is_ok = FALSE ;    /* else set error cuz no hyphen
                       yet more */
        else ;     /* else its whitespace and can continue or end */
      } /* end switch */

        /* pad */
    while ( len-- )    /* while there are empty spots in call */
        *wk++ = ' ' << 1 ;

    *wk++ = ssid ;    /* write ssid byte, no E set */

    *wk++ = NULL ;

    return    ( is_ok ? chr : FALSE ); /* return with ptr to nx call or
                        NIL if error */
}


char *calltoa( buffer , call ) /* convert call to ascii, result to buffer */
byte *buffer;
char *call;    /* char after ssid pointed to in return arg */
{
    register int    i ;
    char *pssid;

    pssid = call + AX25_ADDRLEN - 1 ;    /* pointer to ssid byte */

    i = 0 ;

    while ( i++ < AX25_ADDRLEN-1 && *call != ' ' << 1 )
        *buffer++ = *call++ >> 1 ;

    if ( i =  *pssid >> 1 & 15 ) /* if ssid != 0 */
        sprintf( buffer , "-%d" , i ) ;
    else
        *buffer = NULL ;    /* else put null here */
    end_if

    return ( pssid + 1 );
}