reven2.types._instance.BitfieldInstance

class documentation

class BitfieldInstance(_Generic[_ValueType]):

A bitfield instance, the result of reading a bitfield from a StructInstance.

You can obtain the value of the field by calling the BitfieldInstance.read method. The returned value will be of the natural type produced by the type of the field, which will be an integer or an enumeration depending on the type sliced by the bitfield.

You can also always get the value of the bitfield as a bitarray with the BitfieldInstance.read_bitarray method.

Lastly, get the information about the field in its structure (name, type, offset) with the BitfieldInstance.info property, or link back to the StructInstance of origin with BitfieldInstance.parent_instance.

Method	`__eq__`	Compares the instance for equality with an object.
Method	`__format__`	Formats the value according to the specified options.
Method	`__hash__`	Returns the hash for this value.
Method	`__init__`	Initializes a new field instance from the struct instance of origin and the selected bitfield.
Method	`__ne__`	Compares the instance for equality with an object.
Method	`__str__`	Returns the nicely printable string representation of this instance.
Method	`assert_enum`	Asserts to the type system that the bitfield produces an enumeration value.
Method	`assert_int`	Asserts to the type system that the bitfield produces an integer value.
Method	`format`	Undocumented
Method	`read`	Reads the value produced by the bitfield.
Method	`read_bitarray`	Reads the bitfield as an array of bits of the size of the bitfield.
Method	`read_enum`	Reads the bitfield after asserting to the type system that it produces an enumeration value.
Method	`read_int`	Reads the bitfield after asserting to the type system that it produces an integer value.
Property	`info`	The information (offset, name, length, position) about the bitfield associated with this instance.
Property	`parent_instance`	The struct instance that this instance originates from.
Instance Variable	`_field`	Undocumented
Instance Variable	`_struct`	Undocumented

def __eq__(self, o):

Compares the instance for equality with an object.

if the object is of type bitarray, it will be considered equal to this instance if it is equal to the underlying bits that this instance is made of.
two BitfieldInstances are considered equal if they have the same underlying Struct, Field and bits.
if the object is neither bitarray nor BitfieldInstance, then it will never be considered equal.

Note

The context where this struct was spawned at is never taken into consideration for the purpose of equality. This means that two BitfieldInstances at different contexts with the same type and bits will be considered equal.
Similarly, the source from which the instance was read is never taken into consideration for the purpose of equality. This means that two BitfieldInstances coming from different addresses in memory or different registers can compare equal if they have the same type and bits.

Parameters
o:`object`	Undocumented
Returns
`bool`	Undocumented

def __format__(self, format_spec):

Formats the value according to the specified options.

The options are expected to be in the format described by reven2.util.parse_colon_separated_key_values.

The options will be passed as argument to format.

See StructInstance.__format__ for examples.

Parameters
format_spec:`str`	Undocumented
Returns
`str`	Undocumented

def __hash__(self):

Returns the hash for this value.

Returns
`int`	Undocumented

def __init__(self, struct_instance, field):

Initializes a new field instance from the struct instance of origin and the selected bitfield.

Warnings

At the moment, this object is not meant to be constructed directly. Use StructInstance.bitfield instead.

Parameters
struct_instance:`StructInstance`	Undocumented
field:`Bitfield`	Undocumented

def __ne__(self, o):

Compares the instance for equality with an object.

if the object is of type bitarray, it will be considered equal to this instance if it is equal to the underlying bits that this instance is made of.
two BitfieldInstances are considered equal if they have the same underlying Struct, Field and bits.
if the object is neither bitarray nor BitfieldInstance, then it will never be considered equal.

Note

The context where this struct was spawned at is never taken into consideration for the purpose of equality. This means that two BitfieldInstances at different contexts with the same type and bits will be considered equal.
Similarly, the source from which the instance was read is never taken into consideration for the purpose of equality. This means that two BitfieldInstances coming from different addresses in memory or different registers can compare equal if they have the same type and bits.

Parameters
o:`object`	Undocumented
Returns
`bool`	Undocumented

def __str__(self):

Returns the nicely printable string representation of this instance.

Returns
`str`	Undocumented

def assert_enum(self):

Asserts to the type system that the bitfield produces an enumeration value.

Information

Returns
`BitfieldInstance[EnumerationInstance]`	the same bitfield instance, but with the additional information for the type system that it returns a `EnumerationInstance`.
Raises
`ValueError`	if the bitfield instance does not, in fact, produce an enumeration value, according to its runtime type.

def assert_int(self):

Asserts to the type system that the bitfield produces an integer value.

Information

Returns
`BitfieldInstance[int]`	the same bitfield instance, but with the additional information for the type system that it returns an `int`.
Raises
`ValueError`	if the bitfield instance does not, in fact, produce an integer value, according to its runtime type.

def format(self, max_depth=1, current_depth=1):

Undocumented

Parameters
max_depth:`int`	Undocumented
current_depth:`int`	Undocumented

def read(self):

Reads the value produced by the bitfield.

Bitfields can produce integer or enumeration type depending on the type they're slicing.

Returns
`_ValueType`	Undocumented

def read_bitarray(self):

Reads the bitfield as an array of bits of the size of the bitfield.

Returns
`_bitarray`	Undocumented

def read_enum(self):

Reads the bitfield after asserting to the type system that it produces an enumeration value.

Calling this method is equivalent to self.assert_enum().read().

Information

Returns
`EnumerationInstance`	the same value as produced by `read`, but with the additional information for the type system that it is an `EnumerationInstance`.
Raises
`ValueError`	if the bitfield instance does not, in fact, produce an enumeration value, according to its runtime type.

def read_int(self):

Reads the bitfield after asserting to the type system that it produces an integer value.

Calling this method is equivalent to self.assert_int().read().

Information

Returns
`int`	the same value as produced by `read`, but with the additional information for the type system that it is an `int`.
Raises
`ValueError`	if the bitfield instance does not, in fact, produce an integer value, according to its runtime type.

@property
info: Bitfield =

The information (offset, name, length, position) about the bitfield associated with this instance.

@property
parent_instance: StructInstance =

The struct instance that this instance originates from.

_field =

Undocumented

_struct =

Undocumented