12.17.2 Unpacker Objects

The Unpacker class offers the following methods:

Resets the string buffer with the given data.

Returns the current unpack position in the data buffer.

Sets the data buffer unpack position to position. You should be careful about using get_position() and set_position().

Returns the current unpack data buffer as a string.

Indicates unpack completion. Raises an Error exception if all of the data has not been unpacked.

In addition, every data type that can be packed with a Packer, can be unpacked with an Unpacker. Unpacking methods are of the form unpack_type(), and take no arguments. They return the unpacked object.

Unpacks a single-precision floating point number.

Unpacks a double-precision floating point number, similarly to unpack_float().

In addition, the following methods unpack strings, bytes, and opaque data:

Unpacks and returns a fixed length string. n is the number of characters expected. Padding with null bytes to guaranteed 4 byte alignment is assumed.

Unpacks and returns a fixed length opaque data stream, similarly to unpack_fstring().

Unpacks and returns a variable length string. The length of the string is first unpacked as an unsigned integer, then the string data is unpacked with unpack_fstring().

Unpacks and returns a variable length opaque data string, similarly to unpack_string().

Unpacks and returns a variable length byte stream, similarly to unpack_string().

The following methods support unpacking arrays and lists:

Unpacks and returns a list of homogeneous items. The list is unpacked one element at a time by first unpacking an unsigned integer flag. If the flag is 1, then the item is unpacked and appended to the list. A flag of 0 indicates the end of the list. unpack_item is the function that is called to unpack the items.

unpack_farray(n, unpack_item)
Unpacks and returns (as a list) a fixed length array of homogeneous items. n is number of list elements to expect in the buffer. As above, unpack_item is the function used to unpack each element.

Unpacks and returns a variable length list of homogeneous items. First, the length of the list is unpacked as an unsigned integer, then each element is unpacked as in unpack_farray() above.

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