int position_blocks(int32_t count, uint8_t *sam_stat)
{
MHVTL_DBG(1, "position_blocks");
if (!tape_loaded(sam_stat))
return -1;
if (MediumType == MEDIA_TYPE_WORM)
OK_to_write = 0;
if (count < 0) {
for (; count < 0; count++) {
if (skip_to_prev_header(sam_stat))
return -1;
if (raw_pos.hdr.blk_type == B_FILEMARK) {
sam_no_sense(SD_FILEMARK, E_MARK, sam_stat);
return -1;
}
}
} else {
for (; count > 0; count--) {
if (skip_to_next_header(sam_stat))
return -1;
if (raw_pos.hdr.blk_type == B_FILEMARK) {
sam_no_sense(SD_FILEMARK, E_MARK, sam_stat);
return -1;
}
}
}
return 0;
}
int position_filemarks_back(uint32_t count, uint8_t *sam_stat)
{
uint32_t residual;
int i;
if (!tape_loaded(sam_stat))
return -1;
if (mam.MediumType == MEDIA_TYPE_WORM)
OK_to_write = 0;
/* Find the block number of the first filemark less than our
current position.
*/
for (i = meta.filemark_count - 1; i >= 0; i--)
if (filemarks[i] < raw_pos.hdr.blk_number)
break;
if (i + 1 >= count)
return position_to_block(filemarks[i - count + 1], sam_stat);
else {
residual = count - i - 1;
if (read_header(0, sam_stat))
return -1;
sam_no_sense(SD_EOM, E_BOM, sam_stat);
put_unaligned_be32(residual, &sense[3]);
return -1;
}
}
int position_blocks_forw(uint32_t count, uint8_t *sam_stat)
{
uint32_t residual;
uint32_t blk_target;
unsigned int i;
if (!tape_loaded(sam_stat))
return -1;
if (mam.MediumType == MEDIA_TYPE_WORM)
OK_to_write = 0;
blk_target = raw_pos.hdr.blk_number + count;
/* Find the first filemark forward from our current position, if any. */
for (i = 0; i < meta.filemark_count; i++) {
MHVTL_DBG(3, "filemark at %ld", (unsigned long)filemarks[i]);
if (filemarks[i] >= raw_pos.hdr.blk_number)
break;
}
/* If there is one, see if it is between our current position and our
desired destination.
*/
if (i < meta.filemark_count) {
if (filemarks[i] >= blk_target)
return position_to_block(blk_target, sam_stat);
residual = blk_target - raw_pos.hdr.blk_number + 1;
if (read_header(filemarks[i] + 1, sam_stat))
return -1;
MHVTL_DBG(1, "Filemark encountered: block %d", filemarks[i]);
sam_no_sense(SD_FILEMARK, E_MARK, sam_stat);
put_unaligned_be32(residual, &sense[3]);
return -1;
}
if (blk_target > eod_blk_number) {
residual = blk_target - eod_blk_number;
if (read_header(eod_blk_number, sam_stat))
return -1;
MHVTL_DBG(1, "EOD encountered");
sam_blank_check(E_END_OF_DATA, sam_stat);
put_unaligned_be32(residual, &sense[3]);
return -1;
}
return position_to_block(blk_target, sam_stat);
}
static int skip_prev_filemark(uint8_t *sam_stat)
{
MHVTL_DBG(1, "skip_prev_filemark");
if (raw_pos.hdr.blk_type == B_FILEMARK)
raw_pos.hdr.blk_type = B_NOOP;
while (raw_pos.hdr.blk_type != B_FILEMARK) {
if (raw_pos.hdr.blk_type == B_BOT) {
sam_no_sense(NO_SENSE, E_BOM, sam_stat);
MHVTL_DBG(2, "Found Beginning of tape");
return -1;
}
if (skip_to_prev_header(sam_stat))
return -1;
}
return 0;
}
int position_blocks_back(uint32_t count, uint8_t *sam_stat)
{
uint32_t residual;
uint32_t blk_target;
int i = -1;
unsigned int num_filemarks = meta.filemark_count;
if (!tape_loaded(sam_stat))
return -1;
if (mam.MediumType == MEDIA_TYPE_WORM)
OK_to_write = 0;
MHVTL_DBG(2, "Position before movement: %d", raw_pos.hdr.blk_number);
if (count < raw_pos.hdr.blk_number)
blk_target = raw_pos.hdr.blk_number - count;
else
blk_target = 0;
/* Find the first filemark prior to our current position, if any. */
if (num_filemarks > 0) {
for (i = num_filemarks - 1; i >= 0; i--) {
MHVTL_DBG(3, "filemark at %ld",
(unsigned long)filemarks[i]);
if (filemarks[i] < raw_pos.hdr.blk_number)
break;
}
}
/* If there is one, see if it is between our current position and our
desired destination.
*/
if (i >= 0) {
if (filemarks[i] < blk_target)
return position_to_block(blk_target, sam_stat);
residual = raw_pos.hdr.blk_number - blk_target;
if (read_header(filemarks[i], sam_stat))
return -1;
MHVTL_DBG(2, "Filemark encountered: block %d", filemarks[i]);
sam_no_sense(SD_FILEMARK, E_MARK, sam_stat);
put_unaligned_be32(residual, &sense[3]);
return -1;
}
if (count > raw_pos.hdr.blk_number) {
residual = count - raw_pos.hdr.blk_number;
if (read_header(0, sam_stat))
return -1;
MHVTL_DBG(1, "BOM encountered");
sam_no_sense(SD_EOM, E_BOM, sam_stat);
put_unaligned_be32(residual, &sense[3]);
return -1;
}
return position_to_block(blk_target, sam_stat);
}
