rust-bitcoin-unsafe-fast/hashes/src/util.rs

463 lines
18 KiB
Rust

// SPDX-License-Identifier: CC0-1.0
#[macro_export]
/// Adds hexadecimal formatting implementation of a trait `$imp` to a given type `$ty`.
macro_rules! hex_fmt_impl(
($reverse:expr, $ty:ident) => (
$crate::hex_fmt_impl!($reverse, $ty, );
);
($reverse:expr, $ty:ident, $($gen:ident: $gent:ident),*) => (
impl<$($gen: $gent),*> $crate::_export::_core::fmt::LowerHex for $ty<$($gen),*> {
#[inline]
fn fmt(&self, f: &mut $crate::_export::_core::fmt::Formatter) -> $crate::_export::_core::fmt::Result {
if $reverse {
$crate::_export::_core::fmt::LowerHex::fmt(&self.0.backward_hex(), f)
} else {
$crate::_export::_core::fmt::LowerHex::fmt(&self.0.forward_hex(), f)
}
}
}
impl<$($gen: $gent),*> $crate::_export::_core::fmt::UpperHex for $ty<$($gen),*> {
#[inline]
fn fmt(&self, f: &mut $crate::_export::_core::fmt::Formatter) -> $crate::_export::_core::fmt::Result {
if $reverse {
$crate::_export::_core::fmt::UpperHex::fmt(&self.0.backward_hex(), f)
} else {
$crate::_export::_core::fmt::UpperHex::fmt(&self.0.forward_hex(), f)
}
}
}
impl<$($gen: $gent),*> $crate::_export::_core::fmt::Display for $ty<$($gen),*> {
#[inline]
fn fmt(&self, f: &mut $crate::_export::_core::fmt::Formatter) -> $crate::_export::_core::fmt::Result {
$crate::_export::_core::fmt::LowerHex::fmt(&self, f)
}
}
impl<$($gen: $gent),*> $crate::_export::_core::fmt::Debug for $ty<$($gen),*> {
#[inline]
fn fmt(&self, f: &mut $crate::_export::_core::fmt::Formatter) -> $crate::_export::_core::fmt::Result {
write!(f, "{:#}", self)
}
}
);
);
/// Adds slicing traits implementations to a given type `$ty`
#[macro_export]
macro_rules! borrow_slice_impl(
($ty:ident) => (
$crate::borrow_slice_impl!($ty, );
);
($ty:ident, $($gen:ident: $gent:ident),*) => (
impl<$($gen: $gent),*> $crate::_export::_core::borrow::Borrow<[u8]> for $ty<$($gen),*> {
fn borrow(&self) -> &[u8] {
&self[..]
}
}
impl<$($gen: $gent),*> $crate::_export::_core::convert::AsRef<[u8]> for $ty<$($gen),*> {
fn as_ref(&self) -> &[u8] {
&self[..]
}
}
)
);
macro_rules! engine_input_impl(
() => (
#[cfg(not(hashes_fuzz))]
fn input(&mut self, mut inp: &[u8]) {
while !inp.is_empty() {
let buf_idx = self.length % <Self as crate::HashEngine>::BLOCK_SIZE;
let rem_len = <Self as crate::HashEngine>::BLOCK_SIZE - buf_idx;
let write_len = cmp::min(rem_len, inp.len());
self.buffer[buf_idx..buf_idx + write_len]
.copy_from_slice(&inp[..write_len]);
self.length += write_len;
if self.length % <Self as crate::HashEngine>::BLOCK_SIZE == 0 {
self.process_block();
}
inp = &inp[write_len..];
}
}
#[cfg(hashes_fuzz)]
fn input(&mut self, inp: &[u8]) {
for c in inp {
self.buffer[0] ^= *c;
}
self.length += inp.len();
}
)
);
/// Creates a new newtype around a [`Hash`] type.
///
/// The syntax is similar to the usual tuple struct syntax:
///
/// ```
/// # use bitcoin_hashes::{hash_newtype, sha256};
/// hash_newtype! {
/// /// Hash of `Foo`.
/// pub struct MyNewtype(pub sha256::Hash);
/// }
/// ```
///
/// You can use any valid visibility specifier in place of `pub` or you can omit either or both, if
/// you want the type or its field to be private.
///
/// Whether the hash is reversed or not when displaying depends on the inner type. However you can
/// override it like this:
///
/// ```
/// # use bitcoin_hashes::{hash_newtype, sha256};
/// hash_newtype! {
/// #[hash_newtype(backward)]
/// struct MyNewtype(sha256::Hash);
/// }
/// ```
///
/// This will display the hash backwards regardless of what the inner type does. Use `forward`
/// instead of `backward` to force displaying forward.
///
/// You can add arbitrary doc comments or other attributes to the struct or it's field. Note that
/// the macro already derives [`Copy`], [`Clone`], [`Eq`], [`PartialEq`],
/// [`Hash`](core::hash::Hash), [`Ord`], [`PartialOrd`]. With the `serde` feature on, this also adds
/// `Serialize` and `Deserialize` implementations.
///
/// You can also define multiple newtypes within one macro call:
///
/// ```
/// # use bitcoin_hashes::{hash_newtype, sha256, hash160};
///
/// hash_newtype! {
/// /// My custom type 1
/// pub struct Newtype1(sha256::Hash);
///
/// /// My custom type 2
/// struct Newtype2(hash160::Hash);
/// }
/// ```
///
/// Note: the macro is internally recursive. If you use too many attributes (> 256 tokens) you may
/// hit recursion limit. If you have so many attributes for a good reason, just raising the limit
/// should be OK. Note however that attribute-processing part has to use [TT muncher] which has
/// quadratic complexity, so having many attributes may blow up compile time. This should be rare.
///
/// [TT muncher]: https://danielkeep.github.io/tlborm/book/pat-incremental-tt-munchers.html
///
// Ever heard of legendary comments warning developers to not touch the code? Yep, here's another
// one. The following code is written the way it is for some specific reasons. If you think you can
// simplify it, I suggest spending your time elsewhere.
//
// If you looks at the code carefully you might ask these questions:
//
// * Why are attributes using `tt` and not `meta`?!
// * Why are the macros split like that?!
// * Why use recursion instead of `$()*`?
//
// None of these are here by accident. For some reason unknown to me, if you accept an argument to
// macro with any fragment specifier other than `tt` it will **not** match any of the rules
// requiring a specific token. Yep, I tried it, I literally got error that `hash_newtype` doesn't
// match `hash_newtype`. So all input attributes must be `tt`.
//
// Originally I wanted to define a bunch of macros that would filter-out hash_type attributes. Then
// I remembered (by seeing compiler error) that calling macros is not allowed inside attributes.
// And no, you can't bypass it by calling a helper macro and passing "output of another macro" into
// it. The whole macro gets passed, not the resulting value. So we have to generate the entire
// attributes. And you can't just place an attribute-producing macro above struct - they are
// considered separate items. This is not C.
//
// Thus struct is generated in a separate macro together with attributes. And since the macro needs
// attributes as the input and I didn't want to create confusion by using `#[]` syntax *after*
// struct, I opted to use `{}` as a separator. Yes, a separator is required because an attribute
// may be composed of multiple token trees - that's the point of "double repetition".
#[macro_export]
macro_rules! hash_newtype {
($($(#[$($type_attrs:tt)*])* $type_vis:vis struct $newtype:ident($(#[$field_attrs:tt])* $field_vis:vis $hash:path);)+) => {
$(
$($crate::hash_newtype_known_attrs!(#[ $($type_attrs)* ]);)*
$crate::hash_newtype_struct! {
$type_vis struct $newtype($(#[$field_attrs])* $field_vis $hash);
$({ $($type_attrs)* })*
}
$crate::hex_fmt_impl!(<$newtype as $crate::Hash>::DISPLAY_BACKWARD, $newtype);
$crate::serde_impl!($newtype, <$newtype as $crate::Hash>::LEN);
$crate::borrow_slice_impl!($newtype);
impl $newtype {
/// Creates this wrapper type from the inner hash type.
#[allow(unused)] // the user of macro may not need this
pub fn from_raw_hash(inner: $hash) -> $newtype {
$newtype(inner)
}
/// Returns the inner hash (sha256, sh256d etc.).
#[allow(unused)] // the user of macro may not need this
pub fn to_raw_hash(self) -> $hash {
self.0
}
/// Returns a reference to the inner hash (sha256, sh256d etc.).
#[allow(unused)] // the user of macro may not need this
pub fn as_raw_hash(&self) -> &$hash {
&self.0
}
}
impl $crate::_export::_core::convert::From<$hash> for $newtype {
fn from(inner: $hash) -> $newtype {
// Due to rust 1.22 we have to use this instead of simple `Self(inner)`
Self { 0: inner }
}
}
impl $crate::_export::_core::convert::From<$newtype> for $hash {
fn from(hashtype: $newtype) -> $hash {
hashtype.0
}
}
impl $crate::Hash for $newtype {
type Engine = <$hash as $crate::Hash>::Engine;
type Bytes = <$hash as $crate::Hash>::Bytes;
const LEN: usize = <$hash as $crate::Hash>::LEN;
const DISPLAY_BACKWARD: bool = $crate::hash_newtype_get_direction!($hash, $(#[$($type_attrs)*])*);
fn engine() -> Self::Engine {
<$hash as $crate::Hash>::engine()
}
fn from_engine(e: Self::Engine) -> Self {
Self::from(<$hash as $crate::Hash>::from_engine(e))
}
#[inline]
fn from_slice(sl: &[u8]) -> Result<$newtype, $crate::FromSliceError> {
Ok($newtype(<$hash as $crate::Hash>::from_slice(sl)?))
}
#[inline]
fn from_byte_array(bytes: Self::Bytes) -> Self {
$newtype(<$hash as $crate::Hash>::from_byte_array(bytes))
}
#[inline]
fn to_byte_array(self) -> Self::Bytes {
self.0.to_byte_array()
}
#[inline]
fn as_byte_array(&self) -> &Self::Bytes {
self.0.as_byte_array()
}
#[inline]
fn all_zeros() -> Self {
let zeros = <$hash>::all_zeros();
$newtype(zeros)
}
}
impl $crate::_export::_core::str::FromStr for $newtype {
type Err = $crate::hex::HexToArrayError;
fn from_str(s: &str) -> $crate::_export::_core::result::Result<$newtype, Self::Err> {
use $crate::hex::{FromHex, HexToBytesIter};
use $crate::Hash;
let inner: <$hash as Hash>::Bytes = if <Self as $crate::Hash>::DISPLAY_BACKWARD {
FromHex::from_byte_iter(HexToBytesIter::new(s)?.rev())?
} else {
FromHex::from_byte_iter(HexToBytesIter::new(s)?)?
};
Ok($newtype(<$hash>::from_byte_array(inner)))
}
}
impl $crate::_export::_core::convert::AsRef<[u8; <$hash as $crate::Hash>::LEN]> for $newtype {
fn as_ref(&self) -> &[u8; <$hash as $crate::Hash>::LEN] {
AsRef::<[u8; <$hash as $crate::Hash>::LEN]>::as_ref(&self.0)
}
}
impl<I: $crate::_export::_core::slice::SliceIndex<[u8]>> $crate::_export::_core::ops::Index<I> for $newtype {
type Output = I::Output;
#[inline]
fn index(&self, index: I) -> &Self::Output {
&self.0[index]
}
}
)+
};
}
// Generates the struct only (no impls)
//
// This is a separate macro to make it more readable and have a separate interface that allows for
// two groups of type attributes: processed and not-yet-processed ones (think about it like
// computation via recursion). The macro recursively matches unprocessed attributes, popping them
// one at a time and either ignoring them (`hash_newtype`) or appending them to the list of
// processed attributes to be added to the struct.
//
// Once the list of not-yet-processed attributes is empty the struct is generated with processed
// attributes added.
#[doc(hidden)]
#[macro_export]
macro_rules! hash_newtype_struct {
($(#[$other_attrs:meta])* $type_vis:vis struct $newtype:ident($(#[$field_attrs:meta])* $field_vis:vis $hash:path);) => {
$(#[$other_attrs])*
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
$type_vis struct $newtype($(#[$field_attrs])* $field_vis $hash);
};
($(#[$other_attrs:meta])* $type_vis:vis struct $newtype:ident($(#[$field_attrs:meta])* $field_vis:vis $hash:path); { hash_newtype($($ignore:tt)*) } $($type_attrs:tt)*) => {
$crate::hash_newtype_struct! {
$(#[$other_attrs])*
$type_vis struct $newtype($(#[$field_attrs])* $field_vis $hash);
$($type_attrs)*
}
};
($(#[$other_attrs:meta])* $type_vis:vis struct $newtype:ident($(#[$field_attrs:meta])* $field_vis:vis $hash:path); { $other_attr:meta } $($type_attrs:tt)*) => {
$crate::hash_newtype_struct! {
$(#[$other_attrs])*
#[$other_attr]
$type_vis struct $newtype($(#[$field_attrs])* $field_vis $hash);
$($type_attrs)*
}
};
}
// Extracts `hash_newtype(forward)` and `hash_newtype(backward)` attributes if any and turns them
// into bool, defaulting to `DISPLAY_BACKWARD` of the wrapped type if the attribute is omitted.
//
// Once an appropriate attribute is found we pass the remaining ones into another macro to detect
// duplicates/conflicts and report an error.
//
// FYI, no, we can't use a helper macro to first filter all `hash_newtype` attributes. We would be
// attempting to match on macros instead. So we must write `hashe_newtype` in each branch.
#[doc(hidden)]
#[macro_export]
macro_rules! hash_newtype_get_direction {
($hash:ty, ) => { <$hash as $crate::Hash>::DISPLAY_BACKWARD };
($hash:ty, #[hash_newtype(forward)] $($others:tt)*) => { { $crate::hash_newtype_forbid_direction!(forward, $($others)*); false } };
($hash:ty, #[hash_newtype(backward)] $($others:tt)*) => { { $crate::hash_newtype_forbid_direction!(backward, $($others)*); true } };
($hash:ty, #[$($ignore:tt)*] $($others:tt)*) => { $crate::hash_newtype_get_direction!($hash, $($others)*) };
}
// Reports an error if any of the attributes is `hash_newtype($direction)`.
//
// This is used for detection of duplicates/conflicts, see the macro above.
#[doc(hidden)]
#[macro_export]
macro_rules! hash_newtype_forbid_direction {
($direction:ident, ) => {};
($direction:ident, #[hash_newtype(forward)] $(others:tt)*) => {
compile_error!(concat!("Cannot set display direction to forward: ", stringify!($direction), " was already specified"));
};
($direction:ident, #[hash_newtype(backward)] $(others:tt)*) => {
compile_error!(concat!("Cannot set display direction to backward: ", stringify!($direction), " was already specified"));
};
($direction:ident, #[$($ignore:tt)*] $(#[$others:tt])*) => {
$crate::hash_newtype_forbid_direction!($direction, $(#[$others])*)
};
}
// Checks (at compile time) that all `hash_newtype` attributes are known.
//
// An unknown attribute could be a typo that could cause problems - e.g. wrong display direction if
// it's missing. To prevent this, we call this macro above. The macro produces nothing unless an
// unknown attribute is found in which case it produces `compile_error!`.
#[doc(hidden)]
#[macro_export]
macro_rules! hash_newtype_known_attrs {
(#[hash_newtype(forward)]) => {};
(#[hash_newtype(backward)]) => {};
(#[hash_newtype($($unknown:tt)*)]) => { compile_error!(concat!("Unrecognized attribute ", stringify!($($unknown)*))); };
($($ignore:tt)*) => {};
}
#[cfg(test)]
mod test {
use crate::{sha256, Hash};
#[test]
fn hash_as_ref_array() {
let hash = sha256::Hash::hash(&[3, 50]);
let r = AsRef::<[u8; 32]>::as_ref(&hash);
assert_eq!(r, hash.as_byte_array());
}
#[test]
fn hash_as_ref_slice() {
let hash = sha256::Hash::hash(&[3, 50]);
let r = AsRef::<[u8]>::as_ref(&hash);
assert_eq!(r, hash.as_byte_array());
}
#[test]
fn hash_borrow() {
use core::borrow::Borrow;
let hash = sha256::Hash::hash(&[3, 50]);
let borrowed: &[u8] = hash.borrow();
assert_eq!(borrowed, hash.as_byte_array());
}
hash_newtype! {
/// Test hash.
struct TestHash(crate::sha256d::Hash);
}
#[test]
fn display() {
let want = "0000000000000000000000000000000000000000000000000000000000000000";
let got = format!("{}", TestHash::all_zeros());
assert_eq!(got, want)
}
#[test]
fn display_alternate() {
let want = "0x0000000000000000000000000000000000000000000000000000000000000000";
let got = format!("{:#}", TestHash::all_zeros());
assert_eq!(got, want)
}
#[test]
fn lower_hex() {
let want = "0000000000000000000000000000000000000000000000000000000000000000";
let got = format!("{:x}", TestHash::all_zeros());
assert_eq!(got, want)
}
#[test]
fn lower_hex_alternate() {
let want = "0x0000000000000000000000000000000000000000000000000000000000000000";
let got = format!("{:#x}", TestHash::all_zeros());
assert_eq!(got, want)
}
#[test]
fn inner_hash_as_ref_array() {
let hash = TestHash::all_zeros();
let r = AsRef::<[u8; 32]>::as_ref(&hash);
assert_eq!(r, hash.as_byte_array());
}
#[test]
fn inner_hash_as_ref_slice() {
let hash = TestHash::all_zeros();
let r = AsRef::<[u8]>::as_ref(&hash);
assert_eq!(r, hash.as_byte_array());
}
}