/*
   =============================================================================
	writern.c -- write a random sector onto a file
	Version 6 -- 1987-12-15 -- D.N. Lynx Crowe

	int
	WriteRN(fcp, buf)
	struct fcb *fcp;
	char *buf;

		Writes a sector onto file 'fcp' from 'buf'.  Seeks as needed.
		Returns SUCCESS (0) if OK,  FAILURE (-1) for errors.
   =============================================================================
*/

#define	DEBUGIT		0

#include "ram.h"

/*
   =============================================================================
	WriteRN(fcp, buf) -- Writes a sector onto file 'fcp' from 'buf'.
	Seeks as needed.  Returns SUCCESS (0) if OK,  FAILURE (-1) for errors.
   =============================================================================
*/

int16_t WriteRN(struct fcb *fcp, int8_t *buf)
{
	int16_t	sv;		/* seek return code */
	int32_t	brc;		/* bios return code */

	if ((sv = _seek(fcp))) {		/* try to find the sector we want */

		if (sv < 0) {			/* seek error ? */

#if DEBUGIT
	if (fsdebug)
		printf("WriteRN():  _seek FAILED (%d) - curlsn=%ld, curdsn=%ld\n",
			sv, fcp->curlsn, fcp->curdsn);
#endif

			errno = EIO;		/* I/O error or seek past EOF */
			return(FAILURE);

		} else if (sv EQ 2) {		/* at hard EOF ? */

			if (_alcnew(fcp)) {	/* allocate a new cluster */

				errno = EIO;
				return(FAILURE);
			}
#if DEBUGIT
	if (fsdebug)
		printf("WriteRN():  cluster allocated - curcls=%d, clsec=%d\n",
			fcp->curcls, fcp->clsec);
#endif

		}
	}

#if DEBUGIT
	if (fsdebug)
		printf("WriteRN():  curlsn=%ld, curdsn=%ld\n",
			fcp->curlsn, fcp->curdsn);
#endif

	/* write the sector */

	if ((brc = BIOS(B_RDWR, 1, buf, 1, (int16_t)fcp->curdsn, 0))) {

#if DEBUGIT
	if (fsdebug)
		printf("WriteRN():  B_RDWR FAILED - brc=%ld\n", brc);
#endif

		_berrno = brc;			/* log the error */
		errno = EIO;			/* ... as an I/O error */
		return(FAILURE);		/* return:  ERROR */
	}

#if	TBUFFER
	_secwr(buf, (int16_t)fcp->curdsn);
#endif

	return(SUCCESS);		/* return:  SUCCESS */
}