/*
Copyright (C) Magna Carta Software, Inc. 1990.  All Rights Reserved
C COMMUNICATIONS TOOLKIT
COMMIO.C -- Basic serial I/O functions (no data translation)
*/

#define  CCT_DEVELOPMENT
#if (defined(CCTW) || defined(_WINDOWS))
    #include <windows.h>
#endif
#include <dos.h>
#include <comm.h>
#include <stdlib.h>


/*
C_WAITC -- Waits a specified time for a character to be received and then
returns:
    c               -- character received;
    EOF             -- if no character received;
    USER_CANCELLED  -- if abort key pressed.
Note:
    1)  Duration is measured in milliseconds (e.g. 500 = 1/2 second);
    2)  Maximum value of duration approx = 1 min (60000 ms).
        Call repeatedly for longer delays;
*/
short c_waitc(COMM_PORT *p, short ch, WORD duration)
{
    WORD ticks, ticksnow;
    short inchar;

    /* CONVERT MILLISECONDS TO 18ths OF A SECOND */
    ticks = max(duration/55, 1);
    ticksnow = peek(REAL_SEG, LOW_TIME);      /* initialize reference count */

    _enable();
    /* CHECK UART FOR BYTE READY */
    while (ticks > 0) {
        if (is_key(p->abort_key)) return(USER_CANCELLED);
        /* IF A CHARACTER IS READY RETURN IT */
        if ((*p->rxstat)(p)) {
            inchar = (*p->c_read)(p);
            if ((ch ==  EOF) || (inchar == ch)) return (inchar);
        }
        if ((WORD) peek(REAL_SEG, LOW_TIME) != ticksnow) {  /* compare new count to old */
            ticksnow = peek(REAL_SEG, LOW_TIME);            /* get new reference point  */
            ticks--;                                        /* and reduce timeout       */
        }
    }

    return (EOF);           /* timed out -- no byte received */
}