12.17.1 Packer Objects
Packer instances have the following methods:
- Returns the current pack buffer as a string.
- Resets the pack buffer to the empty string.
In general, you can pack any of the most common XDR data types by calling the
pack_type() method. Each method takes a single
argument, the value to pack. The following simple data type packing methods are supported:
pack_uint(), pack_int(), pack_enum(), pack_bool(), pack_uhyper(),
- Packs the single-precision floating point number value.
- Packs the double-precision floating point number value.
The following methods support packing strings, bytes, and opaque data:
- Packs a fixed length string, s. n is the length of the string
but it is not packed into the data buffer. The string is padded with null bytes
if necessary to guaranteed 4 byte alignment.
- Packs a fixed length opaque data stream, similarly to pack_fstring().
- Packs a variable length string, s. The length of the string is first
packed as an unsigned integer, then the string data is packed with pack_fstring().
- Packs a variable length opaque data string, similarly to pack_string().
- Packs a variable length byte stream, similarly to pack_string().
The following methods support packing arrays and lists:
- Packs a list of homogeneous items. This method is useful for lists with
an indeterminate size; i.e. the size is not available until the entire list has been
walked. For each item in the list, an unsigned integer
1 is packed first,
followed by the data value from the list. pack_item is the function that is
called to pack the individual item. At the end of the list, an unsigned integer
For example, to pack a list of integers, the code might appear like this:
p = xdrlib.Packer()
p.pack_list([1, 2, 3], p.pack_int)
||n, array, pack_item)
- Packs a fixed length list (array) of homogeneous items. n is
the length of the list; it is not packed into the buffer, but a ValueError exception is raised if
is not equal to n. As above, pack_item is the function used to
pack each element.
- Packs a variable length list of homogeneous items. First, the length of
the list is packed as an unsigned integer, then each element is packed as in pack_farray() above.