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//! A documentation-only module for #[deku] attributes //! //! # List of attributes //! //! | Attribute | Scope | Description //! |-----------|------------------|------------ //! | [endian](#endian) | top-level, field | Set the endianness //! | [bits](#bits) | field | Set the bit-size of the field //! | [bytes](#bytes) | field | Set the byte-size of the field //! | [len](#len) | field | Set the field representing the element count of a container //! | [reader](#readerwriter) | variant, field | Custom reader code //! | [writer](#readerwriter) | variant, field | Custom writer code //! | [id](#id) | variant | variant id value, paired with `id_type` //! | [id_type](#id_type) | top-level (enum only) | Set the type of the variant `id` //! | [id_bits](#id_bits) | top-level (enum only) | Set the bit-size of the variant `id` //! | [id_bytes](#id_bytes) | top-level (enum only) | Set the byte-size of the variant `id` //! //! # endian //! //! Set to read/write bytes in a specific byte order. //! //! Values: `big` or `little` //! //! Precedence: field > top-level > system endianness (default) //! //! Example: //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(Debug, PartialEq, DekuRead, DekuWrite)] //! #[deku(endian = "little")] // top-level, defaults to system endianness //! struct DekuTest { //! #[deku(endian = "big")] // field-level override //! field_be: u16, //! field_default: u16, // defaults to top-level //! } //! //! let data: Vec<u8> = vec![0xAB, 0xCD, 0xAB, 0xCD]; //! //! let value = DekuTest::try_from(data.as_ref()).unwrap(); //! //! assert_eq!( //! DekuTest { //! field_be: 0xABCD, //! field_default: 0xCDAB, //! }, //! value //! ); //! //! let value: Vec<u8> = value.into(); //! assert_eq!(data, value); //! ``` //! //! # bits //! //! Set the bit-size of the field //! //! **Note**: Cannot be used in combination with [bytes](#bytes) //! //! Example: //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(Debug, PartialEq, DekuRead, DekuWrite)] //! struct DekuTest { //! #[deku(bits = 2)] //! field_a: u8, //! #[deku(bits = 6)] //! field_b: u8, //! field_c: u8, // defaults to size_of<u8>*8 //! } //! //! let data: Vec<u8> = vec![0b11_101010, 0xFF]; //! //! let value = DekuTest::try_from(data.as_ref()).unwrap(); //! //! assert_eq!( //! DekuTest { //! field_a: 0b11, //! field_b: 0b101010, //! field_c: 0xFF, //! }, //! value //! ); //! //! let value: Vec<u8> = value.into(); //! assert_eq!(data, value); //! ``` //! //! # bytes //! //! Set the byte-size of the field //! //! **Note**: Cannot be used in combination with [bits](#bits) //! //! Example: //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(Debug, PartialEq, DekuRead, DekuWrite)] //! struct DekuTest { //! #[deku(bytes = 2)] //! field_a: u32, //! field_b: u8, // defaults to size_of<u8> //! } //! //! let data: Vec<u8> = vec![0xAB, 0xCD, 0xFF]; //! //! let value = DekuTest::try_from(data.as_ref()).unwrap(); //! //! assert_eq!( //! DekuTest { //! field_a: 0xCDAB, //! field_b: 0xFF, //! }, //! value //! ); //! //! let value: Vec<u8> = value.into(); //! assert_eq!(data, value); //! ``` //! //! # len //! //! Specify the field representing the length of the container, i.e. a Vec //! //! Example: //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(Debug, PartialEq, DekuRead, DekuWrite)] //! struct DekuTest { //! count: u8, //! #[deku(len = "count")] //! items: Vec<u8>, //! } //! //! let data: Vec<u8> = vec![0x02, 0xAB, 0xCD]; //! //! let value = DekuTest::try_from(data.as_ref()).unwrap(); //! //! assert_eq!( //! DekuTest { //! count: 0x02, //! items: vec![0xAB, 0xCD], //! }, //! value //! ); //! //! let value: Vec<u8> = value.into(); //! assert_eq!(data, value); //! ``` //! //! **Note**: calling `.update()` on a struct derived with `DekuWrite` will update the `len` field! //! //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(Debug, PartialEq, DekuRead, DekuWrite)] //! # struct DekuTest { //! # count: u8, //! # #[deku(len = "count")] //! # items: Vec<u8>, //! # } //! # //! let data: Vec<u8> = vec![0x02, 0xAB, 0xCD]; //! //! let mut value = DekuTest::try_from(data.as_ref()).unwrap(); //! //! assert_eq!( //! DekuTest { count: 0x02, items: vec![0xAB, 0xCD] }, //! value //! ); //! //! value.items.push(0xFF); // new item! //! value.update(); //! //! assert_eq!( //! DekuTest { count: 0x03, items: vec![0xAB, 0xCD, 0xFF] }, //! value //! ); //! //! let value: Vec<u8> = value.into(); //! assert_eq!(vec![0x03, 0xAB, 0xCD, 0xFF], value); //! ``` //! //! # reader/writer //! //! Specify custom reader or writer tokens for reading a field or variant //! //! Example: //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(PartialEq, Debug, DekuRead, DekuWrite)] //! struct DekuTest { //! #[deku( //! reader = "DekuTest::read(rest, input_is_le, field_bits)", //! writer = "DekuTest::write(&self.field_a, output_is_le, field_bits)" //! )] //! field_a: String, //! } //! //! impl DekuTest { //! // Read and convert to String //! fn read( //! rest: &BitSlice<Msb0, u8>, //! input_is_le: bool, //! bit_size: Option<usize>, //! ) -> Result<(&BitSlice<Msb0, u8>, String), DekuError> { //! let (rest, value) = u8::read(rest, input_is_le, bit_size, None)?; //! Ok((rest, value.to_string())) //! } //! //! // Parse from String to u8 and write //! fn write(field_a: &str, output_is_le: bool, bit_size: Option<usize>) -> BitVec<Msb0, u8> { //! let value = field_a.parse::<u8>().unwrap(); //! value.write(output_is_le, bit_size) //! } //! } //! //! let data: Vec<u8> = vec![0x01]; //! //! let value = DekuTest::try_from(data.as_ref()).unwrap(); //! //! assert_eq!( //! DekuTest { field_a: "1".to_string() }, //! value //! ); //! //! //! let value: Vec<u8> = value.into(); //! assert_eq!(data, value); //! ``` //! //! # id //! //! Specify the identifier of the enum variant, must be paired with [id_type](#id_type) //! //! Example: //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(PartialEq, Debug, DekuRead, DekuWrite)] //! #[deku(id_type = "u8")] //! enum DekuTest { //! #[deku(id = "0x01")] //! VariantA(u8), //! #[deku(id = "0x02")] //! VariantB(u8, u16), //! } //! //! let data: Vec<u8> = vec![0x01, 0xFF, 0x02, 0xAB, 0xEF, 0xBE]; //! //! let (rest, value) = DekuTest::from_bytes((data.as_ref(), 0)).unwrap(); //! //! assert_eq!( //! DekuTest::VariantA(0xFF), //! value //! ); //! //! let variant_bytes: Vec<u8> = value.into(); //! assert_eq!(vec![0x01, 0xFF], variant_bytes); //! //! let (rest, value) = DekuTest::from_bytes(rest).unwrap(); //! # assert_eq!(0, rest.0.len()); //! # assert_eq!(0, rest.1); //! //! assert_eq!( //! DekuTest::VariantB(0xAB, 0xBEEF), //! value //! ); //! //! let variant_bytes: Vec<u8> = value.into(); //! assert_eq!(vec![0x02, 0xAB, 0xEF, 0xBE], variant_bytes); //! ``` //! //! # id_type //! //! Specify the type of the enum variant id, see [example](#id) //! //! # id_bits //! //! Set the bit size of the enum variant `id` //! //! **Note**: Cannot be used in combination with [id_bytes](#id_bytes) //! //! Example: //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(PartialEq, Debug, DekuRead, DekuWrite)] //! #[deku(id_type = "u8", id_bits = "4")] //! enum DekuTest { //! #[deku(id = "0b1001")] //! VariantA( #[deku(bits = "4")] u8, u8), //! } //! //! let data: Vec<u8> = vec![0b1001_0110, 0xFF]; //! //! let (rest, value) = DekuTest::from_bytes((&data, 0)).unwrap(); //! //! assert_eq!( //! DekuTest::VariantA(0b0110, 0xFF), //! value //! ); //! //! let value: Vec<u8> = value.into(); //! assert_eq!(data, value); //! ``` //! //! # id_bytes //! //! Set the byte size of the enum variant `id` //! //! **Note**: Cannot be used in combination with [id_bits](#id_bits) //! //! Example: //! ```rust //! # use deku::prelude::*; //! # use std::convert::TryFrom; //! # #[derive(PartialEq, Debug, DekuRead, DekuWrite)] //! #[deku(id_type = "u32", id_bytes = "2")] //! enum DekuTest { //! #[deku(id = "0xBEEF")] //! VariantA(u8), //! } //! //! let data: Vec<u8> = vec![0xEF, 0xBE, 0xFF]; //! //! let value = DekuTest::try_from(data.as_ref()).unwrap(); //! //! assert_eq!( //! DekuTest::VariantA(0xFF), //! value //! ); //! //! let value: Vec<u8> = value.into(); //! assert_eq!(data, value); //! ``` //!