/*
*
* Perform a seek operation on a buffered file.
*
* Parameters:
* fio - fdinfo pointer
* pos - requested byte offset
* whence - SEEK_SET, SEEK_CUR, or SEEK_END
* stat - status return word
*
* Return value:
*
* The new byte postion in the file.
* If an error occurs, -1 is returned, and the stat->sw_error field is
* set.
*/
_ffseek_t
_sqb_seek(struct fdinfo *fio, off_t pos, int whence, struct ffsw *stat)
{
_ffseek_t ret;
struct sqb_f *sqb_info;
int sync = 0;
struct fdinfo *llfio;
sqb_info = (struct sqb_f *)fio->lyr_info;
llfio = fio->fioptr;
/* We could probably do more record keeping, and */
/* determine whether the desired position was already */
/* in our buffers. */
/* Wait for outstanding I/O */
if (fio->rwflag == READIN || fio->rwflag == POSITIN) {
if (whence == SEEK_CUR)
sync = 1; /* synchronize physical and logical */
/* positions */
if (_sqb_sync(fio, stat, sync) < 0) {
return(ERR);
}
}
else if (fio->rwflag == WRITIN) {
if (_sqb_flush(fio, stat) < 0) {
return(ERR);
}
}
fio->rwflag = POSITIN;
ret = XRCALL(llfio, seekrtn) llfio, pos, whence, stat);
return(ret);
}
/*
* Write an EOF to a buffer-layer file.
*
*/
int
_sqb_weof(struct fdinfo *fio, struct ffsw *stat)
{
struct fdinfo *llfio;
if (fio->rwflag == WRITIN) {
if (_sqb_flush(fio, stat) < 0) {
return(ERR);
}
}
else if (fio->rwflag == READIN || fio->rwflag == POSITIN) {
/* synchronize physical position with logical */
if (_sqb_sync(fio, stat, 1) < 0) {
return(ERR);
}
}
fio->rwflag = WRITIN;
/*
* Tell the underlying layer to write an EOF
*/
llfio = fio->fioptr;
if (XRCALL(llfio,weofrtn) llfio, stat) == ERR)
return(ERR);
SETSTAT(stat, FFEOF, 0);
return(0);
}
int
_sqb_pos(struct fdinfo *fio, int cmd, long *arg, int len, struct ffsw *stat)
{
int ret = 0;
struct sqb_f *sqb_info;
struct sqbio *sqbptr;
struct sqbio *sqborig;
struct sqbio *s;
struct fdinfo *llfio;
int found = 0;
int nbits;
int sync = -1;
llfio = fio->fioptr;
sqb_info = (struct sqb_f *)fio->lyr_info;
if (fio->rwflag == WRITIN) {
/* flush buffers and wait for outstanding I/O to finish. */
if (_sqb_flush(fio, stat) < 0) {
return(ERR);
}
}
switch(cmd) {
/* For now, this is not supported on SGI systems. */
/* We need to work out what "arg" should be. */
#if !defined(__mips) && !defined(_LITTLE_ENDIAN)
case FP_RSEEK:
if ((fio->rwflag == READIN) ||
(fio->rwflag == POSITIN)) {
if (*arg < 0) {
/* Seeking backwards */
/* Are we seeking within the current */
/* buffer? */
sqbptr = sqb_info->sqbio_cur;
if (sqbptr->status == IOACTIVE) {
while (sqbptr->iostat.sw_flag == 0 ||
sqbptr->iostat.sw_stat == 0) {
ret = XRCALL(llfio,fcntlrtn) llfio,
FC_RECALL, &(sqbptr->iostat), stat);
if (ret < 0) {
return(ERR);
}
}
if (FFSTAT(sqbptr->iostat) == FFERR) {
ERETURN(stat, sqbptr->iostat.sw_error,0);
}
sqbptr->_cnt = sqbptr->iostat.sw_count<<3;
sqbptr->status = IODATA;
}
if (sqbptr->status == IODATA) {
nbits = -(*arg); /* convert to positive */
nbits = nbits<<3;
if (nbits <=
SUBT_BPTR(sqb_info->_ptr,sqbptr->_base)){
SET_BPTR(sqb_info->_ptr,
INC_BPTR(sqb_info->_ptr,-nbits));
sqbptr->_cnt += nbits;
break;
}
}
}
else {
/* seeking forward */
/* Any chance that the position would be in */
/* our buffers? */
nbits = *arg << 3;
if (nbits > sqb_info->nbuf * sqb_info->bufsiz){
/* won't be in any of the buffers */
goto a1;
}
sqbptr = sqb_info->sqbio_cur;
sqborig = sqbptr;
do {
if (sqbptr->status == IOACTIVE) {
while (sqbptr->iostat.sw_flag == 0 ||
sqbptr->iostat.sw_stat == 0) {
ret = XRCALL(llfio,fcntlrtn) llfio,
FC_RECALL, &(sqbptr->iostat), stat);
if (ret < 0) {
return(ERR);
}
}
if (FFSTAT(sqbptr->iostat) == FFERR) {
ERETURN(stat, sqbptr->iostat.sw_error,0);
}
sqbptr->_cnt = sqbptr->iostat.sw_count<<3;
sqbptr->status = IODATA;
}
if (sqbptr->status == IODATA) {
if (nbits <= sqbptr->_cnt) {
/* Desired position is in this buffer */
sqbptr->_cnt -= nbits;
/* Clear out buffers that preceeded this */
s = sqborig;
for (; s != sqbptr; s= s->nxt) {
s->status = EMPTY;
CLRFFSTAT(s->iostat);
}
sqb_info->sqbio_cur = sqbptr;
if (sqbptr != sqborig)
sqb_info->_ptr = sqbptr->_base;
SET_BPTR(sqb_info->_ptr,
INC_BPTR(sqb_info->_ptr,nbits));
found = 1;
break;
}
else {
nbits -= sqbptr->_cnt;
}
}
else
goto a1; /* all out of data */
sqbptr = sqbptr->nxt;
} while (sqbptr != sqborig);
}
}
