/* lfgetmode.c - lfgetmode */

#include 

/*------------------------------------------------------------------------
 * lfgetmode  -  Parse mode argument and generate integer of mode bits
 *------------------------------------------------------------------------
 */
int32   lfgetmode (
         char   *mode                   /* String of mode characters    */
        )
{
        int32   mbits;                  /* Mode bits to return          */
        char    ch;                     /* Next char in mode string     */

        mbits = 0;

        /* Mode string specifies:                                       */
        /*      r - read                                                */
        /*      w - write                                               */
        /*      o - old (file must exist)                               */
        /*      n - new (create a new file)                             */

        while ( (ch = *mode++) != NULLCH) {
                switch (ch) {

                    case 'r':   if (mbits&LF_MODE_R) {
                                        return SYSERR;
                                }
                                mbits |= LF_MODE_R;
                                continue;

                    case 'w':   if (mbits&LF_MODE_W) {
                                        return SYSERR;
                                }
                                mbits |= LF_MODE_W;
                                continue;

                    case 'o':   if (mbits&LF_MODE_O || mbits&LF_MODE_N) {
                                        return SYSERR;
                                }
                                mbits |= LF_MODE_O;
                                break;

                    case 'n':   if (mbits&LF_MODE_O || mbits&LF_MODE_N) {
                                        return SYSERR;
                                }
                                mbits |= LF_MODE_N;
                                break;

                    default:    return SYSERR;
                }
        }

        /* If neither read nor write specified, allow both */

        if ( (mbits&LF_MODE_RW) == 0 ) {
                mbits |= LF_MODE_RW;
        }
        return mbits;
}