super_bit_field

Description:

super bit field

A bit field code generator base on super_annotation for dart.
Getting started #
First, add super_annotations, super_bit_field as dependencies, and build_runner as a dev_dependency.
pub add super_annotations super_bit_field
pub add --dev build_runner
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For every pub command prefix it with either dart or flutter depending on your project.

Usage #
Asume you have a dart file named test_bit_field.dart in your project. You can define a bit field class in it like this:
@BitFieldGen(runAfter: [BitFieldGen.addPartOfDirective])
library test_bit_field;

import 'package:super_bit_field/super_bit_field.dart';
part 'test_bit_field.g.dart';


@BitField(32)
class TestBitField {
@Bits(2)
late int twoBits; // 0-1

@Bits(1)
late int oneBit; // 2-2

@Bits(3)
late int threeBits; // 3-5

late int value;

factory TestBitField(int value, [
GetSetHook<int> hook
]) = _TestBitField;
}
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Then run build_runner to generate the part file.
pub run build_runner build
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For every pub command prefix it with either dart or flutter depending on your project.

The generated part file named test_bit_field.g.dart will be like this:
part of 'test_bit_field.dart';

class _TestBitField implements TestBitField {
_TestBitField(
int value, [
GetSetHook<int>? hook,
]) : _value = value,
_hook = hook;

static const int length = 32;

static const int musk = ((0x01 << length) - 1);

int _value = 0;

final GetSetHook<int>? _hook;

static const int twoBitsBits = 2;

static const int oneBitBits = 1;

static const int threeBitsBits = 3;

static const int twoBitsOffset = 0;

static const int oneBitOffset = 2;

static const int threeBitsOffset = 3;

static const int twoBitsMask = ((0x01 << twoBitsBits) - 1) << twoBitsOffset;

static const int oneBitMask = ((0x01 << oneBitBits) - 1) << oneBitOffset;

static const int threeBitsMask =
((0x01 << threeBitsBits) - 1) << threeBitsOffset;

@override
int get value {
if (_hook != null && _hook.onGet != null) {
_value = _hook.onGet!();
}
return _value;
}

@override
set value(value) {
_value = value;
if (_hook != null && _hook.onSet != null) {
_hook.onSet!(_value);
}
}

@override
int get twoBits => ((value & twoBitsMask) >> twoBitsOffset);

@override
int get oneBit => ((value & oneBitMask) >> oneBitOffset);

@override
int get threeBits => ((value & threeBitsMask) >> threeBitsOffset);

@override
set twoBits(int v) =>
value = (value & ~twoBitsMask) | ((v << twoBitsOffset) & twoBitsMask);

@override
set oneBit(int v) =>
value = (value & ~oneBitMask) | ((v << oneBitOffset) & oneBitMask);

@override
set threeBits(int v) => value =
(value & ~threeBitsMask) | ((v << threeBitsOffset) & threeBitsMask);
}

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Then you can operate the bit field in the class you defined.

void main() {
var bitField = TestBitField(0);
bitField.twoBits = 1;
bitField.oneBit = 1;
bitField.threeBits = 1;
print(bitField.value.toRadixString(2));
print(bitField.twoBits);
print(bitField.oneBit);
print(bitField.threeBits);
}

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You can also opperate a external int value with a bit field object by using GetSetHook.
void main() {
int value = 0;
TestBitField testBitField = TestBitField(value, GetSetHook<int>(onSet: (int v) {
value = v;
}, onGet: () {
return value;
}));
testBitField.twoBits = 2;
print(value); // 2
testBitField.oneBit = 1;
print(value); // 6
testBitField.threeBits = 5;
print(value); // 46
}
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