/*
 * os2iot.c
 *
 * keyboard thread for OS/2.
 *
 */

/* Created by John W. Kennedy */
/* Based on pre-existing mscio.c */
/* KbdCharIn is performed in a separate thread so that timed keyboard I/O */
/*   (as in Border Zone) does not burn up the CPU with polling */
/* A functional change is that the cursor is forced visible during a read, */
/*   which is necessary to make the forms in Bureaucracy usable */

#include "ztypes.h"

#define                 INCL_NOCOMMON
#define                 INCL_DOSSEMAPHORES
#define                 INCL_VIO
#define                 INCL_KBD
#define                 INCL_NOPMAPI
#include <os2.h>

HEV                     hevKbdReq, hevKbdRsp;
volatile int            fKbdOpen;
volatile int            iKbdChar;


static int              os2_read_key_byte (void) {

   /* Use this to hold a two-byte value and return it one byte at a time */
   static int              iExtend = -1;

   /* If we have saved the second half, return it now, and reset */
   if (iExtend >= 0) {

      int                     i = iExtend;

      iExtend = -1;
      return i;

   } else {

      VIOCURSORINFO           vci;
      KBDKEYINFO              kki;
      SHORT                   sAttr;

      /* If we are doing input with the cursor off, turn it on temporarily */
      VioGetCurType (&vci, NULLHANDLE);
      if ((sAttr = vci.attr) != 0) {
         vci.attr = 0;
         VioSetCurType (&vci, NULLHANDLE);
      } /* endif */

      /* Do the actual read */
      KbdCharIn (&kki, IO_WAIT, NULLHANDLE);

      /* If we turned the cursor on, turn it off again */
      if (sAttr) {
         vci.attr = sAttr;
         VioSetCurType (&vci, NULLHANDLE);
      } /* endif */

      /* If we received a two-byte code, save it to return the second half */
      if (kki.chChar == 0x00 || kki.chChar == 0xE0) {
         iExtend = kki.chScan;
      } /* endif */
      return kki.chChar;

   } /* endif */

}/* os2_read_key_byte */


/* This is the actual thread process; we don't need an argument */
void                    os2_read_key_thread (
   void                    *p) {

   /* Unbroken loop */
   for (; ; ) {

      ULONG                   ulPostCt;

      /* Wait for a request from the main thread */
      DosWaitEventSem (hevKbdReq, SEM_INDEFINITE_WAIT);
      DosResetEventSem (hevKbdReq, &ulPostCt);

      /* Either get a byte and post back or shut down the thread */
      if (fKbdOpen) {
         iKbdChar = os2_read_key_byte();
         DosPostEventSem (hevKbdRsp);
      } else {
         break;
      } /* endif */

   } /* endfor */

} /* os2_read_key_thread */