Python io.SEEK_CUR属性代码示例

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def seek(self, offset: int, whence: int = io.SEEK_SET) -> int:
        self._check_open()
        self._check_random()
        if whence == io.SEEK_SET:
            ok = self.dev.seek(offset)
        elif whence == io.SEEK_CUR:
            ok = self.dev.seek(self.tell() + offset)
        elif whence == io.SEEK_END:
            ok = self.dev.seek(len(self) + offset)
        else:
            raise io.UnsupportedOperation("whence = {} is not "
                                          "supported!".format(whence))
        if not ok:
            raise QtOSError(self.dev, msg="seek failed!")

        return self.dev.pos() 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def seek(self, offset, whence=io.SEEK_SET):
        if whence == io.SEEK_CUR:
            offset = self.tell() + offset
        elif whence == io.SEEK_END:
            offset = self.dir.byte_size + offset
        if offset < 0:
            raise ValueError('New position is before the start of the stream')

        if offset > self.dir.byte_size:
            # logging.debug("overseek %d bytes, padding with zeros" % (offset - self.dir.byte_size))
            self.pos = self.dir.byte_size
            bytes_left = offset - self.dir.byte_size
            min_seek_size = self.storage.sector_size * 4
            while bytes_left:
                bytes_to_write = min(min_seek_size, offset - self.dir.byte_size)
                zeros = bytearray(bytes_to_write)
                self.write(zeros)
                bytes_left -= bytes_to_write

        self.pos = offset
        return offset 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def __init__(self, fobj):
        """
        fobj is a file-like object as an icns resource
        """
        # signature : (start, length)
        self.dct = dct = {}
        self.fobj = fobj
        sig, filesize = nextheader(fobj)
        if sig != b"icns":
            raise SyntaxError("not an icns file")
        i = HEADERSIZE
        while i < filesize:
            sig, blocksize = nextheader(fobj)
            if blocksize <= 0:
                raise SyntaxError("invalid block header")
            i += HEADERSIZE
            blocksize -= HEADERSIZE
            dct[sig] = (i, blocksize)
            fobj.seek(blocksize, io.SEEK_CUR)
            i += blocksize 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def __init__(self, fobj):
        """
        fobj is a file-like object as an icns resource
        """
        # signature : (start, length)
        self.dct = dct = {}
        self.fobj = fobj
        sig, filesize = nextheader(fobj)
        if sig != b'icns':
            raise SyntaxError('not an icns file')
        i = HEADERSIZE
        while i < filesize:
            sig, blocksize = nextheader(fobj)
            if blocksize <= 0:
                raise SyntaxError('invalid block header')
            i += HEADERSIZE
            blocksize -= HEADERSIZE
            dct[sig] = (i, blocksize)
            fobj.seek(blocksize, io.SEEK_CUR)
            i += blocksize 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def seek(self, offset, whence=io.SEEK_SET):
        if self.mode == WRITE:
            if whence != io.SEEK_SET:
                if whence == io.SEEK_CUR:
                    offset = self.offset + offset
                else:
                    raise ValueError('Seek from end not supported')
            if offset < self.offset:
                raise OSError('Negative seek in write mode')
            count = offset - self.offset
            chunk = bytes(1024)
            for i in range(count // 1024):
                self.write(chunk)
            self.write(bytes(count % 1024))
        elif self.mode == READ:
            self._check_not_closed()
            return self._buffer.seek(offset, whence)

        return self.offset 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def seek(self, offset, whence=io.SEEK_SET):
        if self.mode == WRITE:
            if whence != io.SEEK_SET:
                if whence == io.SEEK_CUR:
                    offset = self.offset + offset
                else:
                    raise ValueError('Seek from end not supported')
            if offset < self.offset:
                raise OSError('Negative seek in write mode')
            count = offset - self.offset
            chunk = b'\0' * 1024
            for i in range(count // 1024):
                self.write(chunk)
            self.write(b'\0' * (count % 1024))
        elif self.mode == READ:
            self._check_not_closed()
            return self._buffer.seek(offset, whence)

        return self.offset 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def test_seek_and_read(self):

        def mkfile(basename, content):
            part = os.path.join(self.tmpdir.name, basename)
            with fopen(part, 'wb') as f:
                f.write(content)
            return part

        content = b'abc\nd\nefgh\nij'
        part1 = mkfile('1', content[:4])
        part2 = mkfile('2', content[4:5])
        part3 = mkfile('3', content[5:])

        with MultiFileReader(part1, part2, part3) as m:
            self.assertEqual(m.size, len(content))
            m.seek(2)
            self.assertEqual(m.read(2), content[2:4])
            m.seek(1)
            self.assertEqual(m.read(len(content) - 2), content[1:-1])
            m.seek(-1, whence=io.SEEK_END)
            self.assertEqual(m.read(10), content[-1:])

            m.seek(4)
            m.seek(-2, whence=io.SEEK_CUR)
            self.assertEqual(m.read(3), content[2:5]) 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def testSliceFileStartEnd(self):
        with tempfile.TemporaryFile() as f:
            f.write(b'123456789')
            f.flush()
            part = FileSlice(f, 0, 5)
            self.assertEqual(len(part), 5)
            self.assertEqual(part.read(), b'12345')
            self.assertEqual(part.read(3), b'')
            part.seek(0, io.SEEK_SET)
            self.assertEqual(part.read(3), b'123')
            self.assertEqual(part.tell(), 3)
            part.seek(-3, io.SEEK_CUR)
            self.assertEqual(part.tell(), 0)
            part.seek(-2, io.SEEK_END)
            self.assertEqual(part.tell(), 3)
            self.assertEqual(part.readall(), b'45')
            with self.assertRaises(IOError):
                part.write('abc')
            with self.assertRaises(IOError):
                part.writelines(['foo', 'bar']) 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def testSliceFileStartLength(self):
        with tempfile.TemporaryFile() as f:
            f.write(b'123456789')
            f.flush()
            part = FileSlice(f, 0, length=5)
            self.assertEqual(len(part), 5)
            self.assertEqual(part.read(), b'12345')
            self.assertEqual(part.read(3), b'')
            part.seek(0)
            self.assertEqual(part.read(3), b'123')
            self.assertEqual(part.tell(), 3)
            part.seek(-3, io.SEEK_CUR)
            self.assertEqual(part.readall(), b'12345')
            with self.assertRaises(IOError):
                part.write('abc')
            with self.assertRaises(IOError):
                part.writelines(['foo', 'bar']) 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def testSanityChecks(self):
        with tempfile.TemporaryFile() as f:
            f.write(b'123456789')
            f.flush()
            with self.assertRaises(ValueError):
                part = FileSlice(f, -5, -2)
            with self.assertRaises(ValueError):
                part = FileSlice(f, 0, -2)
            with self.assertRaises(ValueError):
                part = FileSlice(f, -10, 2)
            with self.assertRaises(ValueError):
                part = FileSlice(f, 10, 2)
            with self.assertRaises(ValueError):
                part = FileSlice(f, 10, length=-2)

            part = FileSlice(f, 1, 5)
            with self.assertRaises(ValueError):
                part.seek(8)
            with self.assertRaises(ValueError):
                part.seek(8, io.SEEK_SET)
            part.seek(3)
            with self.assertRaises(ValueError):
                part.seek(4, io.SEEK_CUR)
            with self.assertRaises(ValueError):
                part.seek(-5, io.SEEK_END) 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def seek(self, offset, whence=io.SEEK_SET):
        if whence == io.SEEK_SET:
            desired_pos = self._start + offset
        if whence == io.SEEK_CUR:
            desired_pos = self._handle.tell() + offset
        if whence == io.SEEK_END:
            desired_pos = self._end + offset

        if desired_pos < self._start:
            raise ValueError("Seeking before the file slice")
        if desired_pos > self._end:
            raise ValueError("Seekeing past the end of file slice")

        ret = self._handle.seek(desired_pos, io.SEEK_SET)
        if ret:
            return ret - self._start
        else:
            return ret 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def seek(self, offset, whence=io.SEEK_SET):
        if whence == io.SEEK_CUR:
            self.offset += offset
        elif whence == io.SEEK_END:
            self.offset = self.cumsizes[-1] + offset
        elif whence == io.SEEK_SET:
            self.offset = offset

        if self.offset < 0:
            raise Exception("Trying to seek before the start of the file!")
        if self.offset >= self.cumsizes[-1]:
            return self.offset

        i = self._findStencil( self.offset )
        offsetInsideStencil = self.offset - self.cumsizes[i]
        assert offsetInsideStencil >= 0
        assert offsetInsideStencil < self.sizes[i]
        self.fileobj.seek( self.offsets[i] + offsetInsideStencil, io.SEEK_SET )

        return self.offset 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def pack(self):
        """ Pack message to binary stream. """
        payload = io.BytesIO()
        # Advance num bytes equal to header size - the header is written later
        # after the payload of all segments and parts has been written:
        payload.seek(self.header_size, io.SEEK_CUR)

        # Write out payload of segments and parts:
        self.build_payload(payload)

        packet_length = len(payload.getvalue()) - self.header_size
        self.header = MessageHeader(self.session_id, self.packet_count, packet_length, constants.MAX_SEGMENT_SIZE,
                                    num_segments=len(self.segments), packet_options=0)
        packed_header = self.header_struct.pack(*self.header)

        # Go back to begining of payload for writing message header:
        payload.seek(0)
        payload.write(packed_header)
        payload.seek(0, io.SEEK_END)

        trace(self)

        return payload 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def pack(self, payload, **kwargs):

        # remember position in payload object:
        segment_payload_start_pos = payload.tell()

        # Advance num bytes equal to header size. The header is written later
        # after the payload of all segments and parts has been written:
        payload.seek(self.header_size, io.SEEK_CUR)

        # Generate payload of parts:
        self.build_payload(payload)

        segment_length = payload.tell() - segment_payload_start_pos  # calc length of parts payload
        self.header = RequestSegmentHeader(segment_length, self.offset, len(self.parts), self.number, self.segment_kind,
                                           self.message_type, int(kwargs.get('commit', 0)), self.command_options)
        packed_header = self.header_struct.pack(*self.header)

        # Go back to beginning of payload header for writing segment header:
        payload.seek(segment_payload_start_pos)
        payload.write(packed_header)
        # Put file pointer at the end of the bffer so that next segment can be appended:
        payload.seek(0, io.SEEK_END) 

# 需要导入模块: import io [as 别名]
# 或者: from io import SEEK_CUR [as 别名]
def seek(self, offset, where=SEEK_SET):
    """Seek the position by `offset` relative to `where`.

    Args:
        offset: move the read pointer by `offset` bytes.
        where: same as io.SEEK_END, io.SEEK_CUR or io.SEEK_SET.
    """
    if where == SEEK_CUR:
      cur = len(self.read_file)
      pos = cur + offset
    elif where == SEEK_END:
      pos = len(self.read_file) + len(self.file) + offset
    else:
      pos = offset
    if pos < 0:
      pos = 0
    self.file = self.read_file + self.file
    self.read_file = self.file[:pos]
    self.file = self.file[pos:]
    self.cur_fd = None