static int decompressor_xz_reset(struct microfs_sb_info* sbi, void* data)
{
struct decompressor_xz_data* xzdat = data;
xz_dec_reset(xzdat->xz_state);
return 0;
}
static int xz_dec_test_open(struct inode *i, struct file *f)
{
if (device_is_open)
return -EBUSY;
device_is_open = true;
xz_dec_reset(state);
ret = XZ_OK;
crc = 0xFFFFFFFF;
buffers.in_pos = 0;
buffers.in_size = 0;
buffers.out_pos = 0;
printk(KERN_INFO DEVICE_NAME ": opened\n");
return 0;
}
static grub_ssize_t
grub_xzio_read (grub_file_t file, char *buf, grub_size_t len)
{
grub_ssize_t ret = 0;
grub_ssize_t readret;
enum xz_ret xzret;
grub_xzio_t xzio = file->data;
grub_off_t current_offset;
/* If seek backward need to reset decoder and start from beginning of file.
TODO Possible improvement by jumping blocks. */
if (file->offset < xzio->saved_offset)
{
xz_dec_reset (xzio->dec);
xzio->saved_offset = 0;
xzio->buf.out_pos = 0;
xzio->buf.in_pos = 0;
xzio->buf.in_size = 0;
grub_file_seek (xzio->file, 0);
}
current_offset = xzio->saved_offset;
while (len > 0)
{
xzio->buf.out_size = grub_min (file->offset + ret + len - current_offset,
XZBUFSIZ);
/* Feed input. */
if (xzio->buf.in_pos == xzio->buf.in_size)
{
readret = grub_file_read (xzio->file, xzio->inbuf, XZBUFSIZ);
if (readret < 0)
return -1;
xzio->buf.in_size = readret;
xzio->buf.in_pos = 0;
}
xzret = xz_dec_run (xzio->dec, &xzio->buf);
switch (xzret)
{
case XZ_MEMLIMIT_ERROR:
case XZ_FORMAT_ERROR:
case XZ_OPTIONS_ERROR:
case XZ_DATA_ERROR:
case XZ_BUF_ERROR:
grub_error (GRUB_ERR_BAD_COMPRESSED_DATA,
"file corrupted or unsupported block options");
return -1;
default:
break;
}
{
grub_off_t new_offset = current_offset + xzio->buf.out_pos;
if (file->offset <= new_offset)
/* Store first chunk of data in buffer. */
{
grub_size_t delta = new_offset - (file->offset + ret);
grub_memmove (buf, xzio->buf.out + (xzio->buf.out_pos - delta),
delta);
len -= delta;
buf += delta;
ret += delta;
}
current_offset = new_offset;
}
xzio->buf.out_pos = 0;
if (xzret == XZ_STREAM_END) /* Stream end, EOF. */
break;
}
if (ret >= 0)
xzio->saved_offset = file->offset + ret;
return ret;
}