Rust procedural macro to quickly generate bitfield from a structure.
Features: - Any size from 8 to 128 bits - Auto implementation of getters and setters, and Default. - Supports the use of other attribute on the structure - Declaration of fields either from the Least Significant Bit or the Most Significant Bit - Supports custom return types (primitives and custom types) - Supports custom visibility for each field - Skip implementation of fields marked as reserved - Implementation of a Pretty Print associated function: pprint()
By default: - starts declaration of fields from the Least Significant Bit; - declares all fields as public; - does not implement the pretty print function;
The macro can be used as following: ```text
Where size can be: u8 u16 u32 u64 u128
There are 3 optional parameters: Order: can be 'lsb' or 'msb' Visibility: 'no_pub' Pretty Print: 'pp'
```
The size parameter will constrain the total size of the bitfield.
The order parameter is optional and will alter the order in which the fields are declared.
By default this parameter is set to lsb.
When setting the order parameter to msb, the first declared field of the struct will be set on the most significant bit, and the other way around when using the lsb mode.
The visibility parameter is optional and will alter the visibility of the declared field. It can be set only to no_pub.
By default, all fields are declared as public, using the flag no_pub will deactivate this behaviour and rely on the visibility declared by the user.
Hence, the size and position of the field is based on the field declaration : ```rust use bitf::bitf;
struct Example
{
anycasename2: (), // () is used to specify to use the raw type defined in the attribute (here is u8)
_reserved4: (), // This field will not be implemented as the name is reserved
nameB2: u16, // Return type override. The get method implemented will return a u16
// Custom types can be used, be will need to implement the From trait
// Please see the test file in "test/attributemacro.rs" for an example
}
// The internal, full value of the field can be accessed as :
let e = Example::default(); println!("{}", e.raw);
// and the representation of the bitfield can be accessed via e.pprint();
```
When combined to other attributes, make sure to implement it BEFORE any #[derive(..)] attribute, or the expansion order might (will) fail.
```rust use bitf::bitf;
struct MyStruct { fieldA4: (), fieldB4: (), } ```
The Pretty Print parameter is set throught the pp switch.
This switch will implement an associated set of functions on the structure, accessible through pprint().
This function will produce the following output (for a 128 bits bitfield):
```text
64 60 59 57 56 40 35 27 23 21 18 17 7 6 3 2 0 ┌──────┬───┬────┬───┬──────────────────┬───────┬──────────┬──────┬────┬─────┬───┬────────────┬───┬─────┬───┬────┐ │ 1111 │ 1 │ 01 │ 0 │ rrrrrrrrrrrrrrrr │ 01101 │ 11110101 │ 0110 │ 00 │ 010 │ 0 │ 1000110101 │ 0 │ 110 │ 0 │ 10 │ └──────┴───┴────┴───┴──────────────────┴───────┴──────────┴──────┴────┴─────┴───┴────────────┴───┴─────┴───┴────┘
``
The field noted as "rrrrrrrr..." symbolizes a reserved field. Such fields are defined when declared with the namereservedusize`
Please note that there is not any mechanism of paging or any clever system to adapt the output to the shell size. Hence, it will probably fail if you try to print a bitfield of 128 1-byte wide fields, unless you have an exceptionnaly wide screen
You can use the following syntax when declaring a field to skip its implementation.
_reserved_intSize
In the previous example, the field _reserved_4 will not have its 4 bits implemented.
No accessor will be generated for this field.
Considering the following bitfield:
```text 7 0 0 0 0 0 0 0 0 0 | | | | | | | |_ fielda - Size 1 | | | | | | | fieldB - Size 1 | | | | | |_ fieldC - Size 1 | | \|/_ reserved - Size 3 \ /___ fieldD - Size 2
```
It can be achieved with the following declaration and macro usage
```rust use bitf::bitf;
struct MyStruct { fielda1: (), fieldB1: (), FieldC1: (), reserved3: (), FieldD2: (), } ```
This will generate the following structure and associated methods
```rust struct MyStruct { pub raw: u8, }
impl MyStruct { pub fn fielda(self: &Self) -> u8 { /* bitwise logic */ 0 } pub fn setfielda(self: &Self, val: u8) { /* bitwise logic */ } pub fn fieldB(self: &Self) -> u8 { /* bitwise logic */ 0 } pub fn setfieldB(self: &Self, val: u8) { /* bitwise logic / } / * And so on... */
}
impl Default for MyStruct { fn default() -> Self { MyStruct { raw: 0x0 } } }
//So you can easily set and read values of each defined bitfield:
let mut bf = MyStruct::default();
bf.setfielda(1); bf.setfieldB(1); println!("{:#010b}", bf.fielda());
```
_reserved_intSize