def descr_init(self, space, w_raw, buffer_size=DEFAULT_BUFFER_SIZE,
max_buffer_size=-234):
if max_buffer_size != -234:
self._complain_about_max_buffer_size(space)
self.state = STATE_ZERO
check_readable_w(space, w_raw)
check_writable_w(space, w_raw)
check_seekable_w(space, w_raw)
self.w_raw = w_raw
self.buffer_size = buffer_size
self.readable = self.writable = True
self._init(space)
self._reader_reset_buf()
self._writer_reset_buf()
self.pos = 0
self.state = STATE_OK
def descr_init(self, space, w_raw, buffer_size=DEFAULT_BUFFER_SIZE,
max_buffer_size = -234):
if max_buffer_size != -234:
self._deprecated_max_buffer_size(space)
self.state = STATE_ZERO
check_readable_w(space, w_raw)
check_writable_w(space, w_raw)
check_seekable_w(space, w_raw)
self.w_raw = w_raw
self.buffer_size = buffer_size
self.readable = self.writable = True
self._init(space)
self._reader_reset_buf()
self._writer_reset_buf()
self.pos = 0
self.state = STATE_OK
def seek_w(self, space, pos, whence=0):
self._check_init(space)
if whence not in (0, 1, 2):
raise oefmt(space.w_ValueError,
"whence must be between 0 and 2, not %d", whence)
self._check_closed(space, "seek of closed file")
check_seekable_w(space, self.w_raw)
if whence != 2 and self.readable:
# Check if seeking leaves us inside the current buffer, so as to
# return quickly if possible. Also, we needn't take the lock in
# this fast path.
if self.abs_pos == -1:
self._raw_tell(space)
current = self.abs_pos
available = self._readahead()
if available > 0:
if whence == 0:
offset = pos - (current - self._raw_offset())
else:
offset = pos
if -self.pos <= offset <= available:
newpos = self.pos + offset
assert newpos >= 0
self.pos = newpos
return space.wrap(current - available + offset)
# Fallback: invoke raw seek() method and clear buffer
with self.lock:
if self.writable:
self._writer_flush_unlocked(space)
self._writer_reset_buf()
if whence == 1:
pos -= self._raw_offset()
n = self._raw_seek(space, pos, whence)
self.raw_pos = -1
if self.readable:
self._reader_reset_buf()
return space.wrap(n)
