/*
 *                  _ c o n w r i t e _ c
 *
 *  This routine is called from the 'write' call when data for
 *  a console or screen device is to be output.    It implements
 *  the handling for the QL screen of the standard ANSI C escape
 *  sequences.
 *  (using ideas from Franz Herrman)
 *
 *  The idea of vectoring the call into this routine is that
 *  this makes it possible to replace this routine with a
 *  full terminal emulator if so desired.    This can be done
 *  in a way that is transparent to user-level programs.
 *
 *  This routine only needs to handle escape sequences.   It can
 *  leave handling of standard strings to the calling routine
 *  by returning the appropriate values.
 *
 *  RETURN VALUES:
 *          +ve     This many bytes (from the start of the data
 *                  buffer passed can be output without doing
 *                  any translation.
 *            0     Output finished.   Either all data has been
 *                  processed or an error occured.
 *          -ve     This many characters from the buffer have been
 *                  consumed in "special" processing.
 *
 * Routine handles writing to all the different
 * types of device.
 *
 *  AMENDMENT HISTORY
 *  ~~~~~~~~~~~~~~~~~
 *  16 Sep 92   DJW     - Rewrote original _writetrans() routine as part of
 *                        an upgrade to support a CURSES library.
 *
 *  12 Nov 95   DJW   - Now get timeout via support routine to allow for
 *                      the setting of the UFB_ND and UFB_NB flags.
 */

#define __LIBRARY__

#include <qdos.h>
#include <fcntl.h>
#include <string.h>

static
int     default_conwrite _LIB_F3_ ( struct UFB *,       uptr,   \
                                    unsigned char *,    buf,    \
                                    unsigned int,       len)
{
    long      to_write;
    chanid_t  chanid;
    timeout_t timeout;
    QLRECT_t  cur;
    int      pos;

    /*
     *  If RAW output is required, then let
     *  the default output routine handle it
     */
    if ((uptr->ufbflg & UFB_NT)) {
        return (long)(len);
    }
    chanid  = uptr->ufbfh;
    timeout = _GetTimeout(uptr);
    /*
     *  Scan data until special character found
     *  Any data before it is output using string I/O
     *  (byte level I/O is to expensive )
     */
    if ((to_write = strcspn ((char *)buf, "\b\r\f\a\t")) != 0) {
        return (to_write > len ? (long)len : to_write);
    }
    /*
     *  If we get here, then one of the special characters
     *  was found.   We must now handle it.
     */
    switch (*buf) {
    case '\b':  /* backspace */
                /* (from Peter Sulzer) */
            (void) sd_pcol( chanid, timeout );
            break;
    case '\r':  /* carriage return */
            (void) sd_tab( chanid, timeout, 0 );
            break;
    case '\a':  /* bell */
            beep( 500, 50 );
            break;
    case '\f':  /* form feed */
            (void) sd_clear( chanid, timeout );
            break;
    case '\t':  /* tabulator */
             /*
              * (using a hint from Hans Lub) 
              * N.B.  We always send at least one space
              *      to ensure pending NL cleared
              */
            (void) io_sbyte (chanid, timeout, ' ');
            (void) sd_chenq (chanid, timeout, &cur );
            if ((pos = cur.q_x % 8) != 0)
                (void) sd_tab ( chanid, timeout, (short)(cur.q_x + (8 - pos)) );
            break;
    default:
            break;
    }
    return (-1);
}

/*===================================================================
 *      Default vector points to this routine
 *------------------------------------------------------------------*/

#ifdef __STDC__
int     (*_conwrite)(UFB_t *, void *, unsigned int) = (int (*)(UFB_t *, void *, unsigned int)) default_conwrite;
#else
int     (*_conwrite)() = default_conwrite;
#endif