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🎨 Refactoring
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@wrenger
wrenger committed Jul 30, 2023
1 parent 3857a23 commit 59f7a9e
Showing 1 changed file with 60 additions and 55 deletions.
115 changes: 60 additions & 55 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -178,10 +178,10 @@
//!
//! > Hint: You can use the rust-analyzer "Expand macro recursively" action to view the generated code.
//!
//! ### Bit Order
//! ## Bit Order
//!
//! The optional `order` macro argument determines the layout of the bits, with the default being
//! Lsb first:
//! Lsb (least significant bit) first:
//!
//! ```
//! # use bitfield_struct::bitfield;
Expand All @@ -190,12 +190,9 @@
//! /// The first field occupies the least significant bits
//! #[bits(4)]
//! kind: usize,
//! /// Booleans are 1 bit large
//! system: bool,
//! /// The bits attribute specifies the bit size of this field
//! #[bits(2)]
//! level: usize,
//! /// The last field spans over the most significant bits
//! present: bool
//! }
//!
Expand All @@ -210,18 +207,20 @@
//! // | | .- system
//! // | | | .- kind
//! assert!(my_byte_lsb.0 == 0b1_10_0_1010);
//! ```
//!
//! The macro generates the reverse order when Msb (most significant bit) is specified:
//!
//! ```
//! # use bitfield_struct::bitfield;
//! #[bitfield(u8, order = Msb)]
//! struct MyMsbByte {
//! /// The first field occupies the least significant bits
//! /// The first field occupies the most significant bits
//! #[bits(4)]
//! kind: usize,
//! /// Booleans are 1 bit large
//! system: bool,
//! /// The bits attribute specifies the bit size of this field
//! #[bits(2)]
//! level: usize,
//! /// The last field spans over the most significant bits
//! present: bool
//! }
//!
Expand All @@ -242,7 +241,7 @@
//!
//! This macro automatically creates a suitable `fmt::Debug` and `Default` implementations
//! similar to the ones created for normal structs by `#[derive(Debug, Default)]`.
//! You can disable this with the extra `debug` and `default` arguments.
//! You can disable these with the extra `debug` and `default` arguments.
//!
//! ```
//! # use std::fmt;
Expand All @@ -269,6 +268,8 @@
//! ```
//!

#![warn(clippy::unwrap_used)]

use proc_macro as pc;
use proc_macro2::{Ident, Span, TokenStream};
use quote::{format_ident, quote, ToTokens};
Expand Down Expand Up @@ -340,7 +341,7 @@ fn bitfield_inner(args: TokenStream, input: TokenStream) -> syn::Result<TokenStr
}

let debug_impl = if debug {
let debug_fields = members.iter().map(|m| m.debug());
let debug_fields = members.iter().map(Member::debug);
quote! {
impl core::fmt::Debug for #name {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
Expand All @@ -351,10 +352,10 @@ fn bitfield_inner(args: TokenStream, input: TokenStream) -> syn::Result<TokenStr
}
}
} else {
Default::default()
TokenStream::default()
};

let defaults = members.iter().map(|m| m.default());
let defaults = members.iter().map(Member::default);

let default_impl = if default {
quote! {
Expand Down Expand Up @@ -558,7 +559,7 @@ impl ToTokens for Member {
.map(ToTokens::to_token_stream)
.collect();

let mask: u128 = !0 >> (u128::BITS - *bits as u32);
let mask = u128::MAX >> (u128::BITS - *bits as u32);
let mask = syn::LitInt::new(&format!("0x{mask:x}"), Span::mixed_site());

let code = quote! {
Expand Down Expand Up @@ -658,52 +659,52 @@ fn parse_field(attrs: &[syn::Attribute], ty: &syn::Type, ignore: bool) -> syn::R

// Find and parse the bits attribute
for attr in attrs {
match attr {
syn::Attribute {
let syn::Attribute {
style: syn::AttrStyle::Outer,
meta: syn::Meta::List(syn::MetaList { path, tokens, .. }),
..
} if path.is_ident("bits") => {
let span = tokens.span();
let BitsAttr {
bits,
default,
into,
from,
} = syn::parse2::<BitsAttr>(tokens.clone()).map_err(|e| malformed(e, attr))?;

if let Some(bits) = bits {
if bits == 0 {
return Err(syn::Error::new(span, "bits cannot bit 0"));
}
if ty_bits != 0 && bits > ty_bits {
return Err(syn::Error::new(span, "overflowing field type"));
}
ret.bits = bits;
} = attr else {
continue
};
if path.is_ident("bits") {
let span = tokens.span();
let BitsAttr {
bits,
default,
into,
from,
} = syn::parse2(tokens.clone()).map_err(|e| malformed(e, attr))?;

if let Some(bits) = bits {
if bits == 0 {
return Err(syn::Error::new(span, "bits cannot bit 0"));
}
if ignore && (into.is_some() || from.is_some()) {
return Err(syn::Error::new(
default.span(),
"'into' and 'from' are not supported on padding",
));
if ty_bits != 0 && bits > ty_bits {
return Err(syn::Error::new(span, "overflowing field type"));
}
ret.bits = bits;
}
if ignore && (into.is_some() || from.is_some()) {
return Err(syn::Error::new(
default.span(),
"'into' and 'from' are not supported on padding",
));
}

if let Some(into) = into {
ret.into = quote!(#into(this));
if let Some(into) = into {
ret.into = quote!(#into(this));
}
if let Some(from) = from {
// Auto-conversion from zero
if default.is_none() {
ret.default = quote!(#from(0));
}
if let Some(from) = from {
// Auto-conversion from zero
if default.is_none() {
ret.default = quote!(#from(0));
}

ret.from = quote!(#from(this));
}
if let Some(default) = default {
ret.default = default.into_token_stream();
}
ret.from = quote!(#from(this));
}
if let Some(default) = default {
ret.default = default.into_token_stream();
}
_ => {}
}
}

Expand All @@ -717,7 +718,7 @@ fn parse_field(attrs: &[syn::Attribute], ty: &syn::Type, ignore: bool) -> syn::R
// Signed integers need some special handling...
if !ignore && class == TypeClass::SInt {
let bits = ret.bits as u32;
let mask: u128 = !0 >> (u128::BITS - ret.bits as u32);
let mask = u128::MAX >> (u128::BITS - ret.bits as u32);
let mask = syn::LitInt::new(&format!("0x{mask:x}"), Span::mixed_site());
if ret.into.is_empty() {
// Bounds check and remove leading ones from negative values
Expand Down Expand Up @@ -835,15 +836,15 @@ impl Parse for Params {
"Lsb" | "lsb" => Order::Lsb,
_ => return Err(syn::Error::new(ident.span(), "unknown value for order")),
};
order = value
order = value;
}
_ => return Err(syn::Error::new(ident.span(), "unknown argument")),
};
}

Ok(Params {
bits,
ty,
bits,
debug,
default,
order,
Expand Down Expand Up @@ -881,7 +882,7 @@ fn type_bits(ty: &syn::Type) -> (TypeClass, usize) {
mod test {
use quote::quote;

use crate::{BitsAttr, Params};
use crate::{BitsAttr, Order, Params};

#[test]
fn parse_args() {
Expand All @@ -892,6 +893,10 @@ mod test {
let args = quote!(u32, debug = false);
let params = syn::parse2::<Params>(args).unwrap();
assert!(params.bits == u32::BITS as usize && params.debug == false);

let args = quote!(u32, order = Msb);
let params = syn::parse2::<Params>(args).unwrap();
assert!(params.bits == u32::BITS as usize && params.order == Order::Msb);
}

#[test]
Expand Down

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