From 848dbd41d63e6293af51394955a1981e9d5da4e6 Mon Sep 17 00:00:00 2001
From: Nagata Kana <ngtkana@gmail.com>
Date: Fri, 29 Nov 2024 14:01:33 +0900
Subject: [PATCH] add i2powm1

---
 libs/lg/src/lib.rs                  | 10 +++++-----
 libs/riff/src/bitmask_operations.rs | 15 +++++++++++++++
 libs/riff/src/lib.rs                |  2 ++
 libs/riff/src/numeric_traits.rs     |  4 ++++
 4 files changed, 26 insertions(+), 5 deletions(-)
 create mode 100644 libs/riff/src/bitmask_operations.rs

diff --git a/libs/lg/src/lib.rs b/libs/lg/src/lib.rs
index c4f41367..e3f3b9f7 100644
--- a/libs/lg/src/lib.rs
+++ b/libs/lg/src/lib.rs
@@ -64,7 +64,7 @@ macro_rules! __lg_internal {
 #[macro_export]
 macro_rules! table {
     ($vec2:expr) => {
-        eprintln!(
+        eprint!(
             "{}",
             $crate::vec2($crate::remove_ampersand(stringify!($vec2)), $vec2)
         );
@@ -74,7 +74,7 @@ macro_rules! table {
 #[macro_export]
 macro_rules! vmap {
     ($map:expr) => {
-        eprintln!(
+        eprint!(
             "{}",
             $crate::vmap($crate::remove_ampersand(stringify!($map)), $map)
         );
@@ -84,7 +84,7 @@ macro_rules! vmap {
 #[macro_export]
 macro_rules! hmap {
     ($map:expr) => {
-        eprintln!(
+        eprint!(
             "{}",
             $crate::hmap($crate::remove_ampersand(stringify!($map)), $map)
         );
@@ -115,7 +115,7 @@ macro_rules! vvec {
                 vecs.push((name.to_owned(), values))
             }
         )+
-        eprintln!("{}", $crate::vvec(&vecs));
+        eprint!("{}", $crate::vvec(&vecs));
     };
 }
 
@@ -143,7 +143,7 @@ macro_rules! hvec {
                 vecs.push((name.to_owned(), values))
             }
         )+
-        eprintln!("{}", $crate::hvec(&vecs));
+        eprint!("{}", $crate::hvec(&vecs));
     };
 }
 
diff --git a/libs/riff/src/bitmask_operations.rs b/libs/riff/src/bitmask_operations.rs
new file mode 100644
index 00000000..082b44a2
--- /dev/null
+++ b/libs/riff/src/bitmask_operations.rs
@@ -0,0 +1,15 @@
+use crate::Unsigned;
+
+/// Returns $2^n - 1$.
+///
+/// # Examples
+/// ```
+/// use crate::i2powm1;
+/// assert_eq!(i2powm1::<u32>(0), 0);
+/// assert_eq!(i2powm1::<u32>(1), 1);
+/// assert_eq!(i2powm1::<u32>(2), 3);
+/// assert_eq!(i2powm1::<u32>(3), 7);
+/// ```
+pub fn i2powm1<T: Unsigned>(n: u32) -> T {
+    T::MAX >> (T::BITS - n)
+}
diff --git a/libs/riff/src/lib.rs b/libs/riff/src/lib.rs
index 2c129752..30b0fa14 100644
--- a/libs/riff/src/lib.rs
+++ b/libs/riff/src/lib.rs
@@ -2,6 +2,7 @@
 
 mod binary_search;
 mod bitmask_iterators;
+mod bitmask_operations;
 mod change_min_max;
 mod numeric_traits;
 mod pop_if;
@@ -9,6 +10,7 @@ mod pop_if;
 pub use binary_search::BinarySearch;
 pub use bitmask_iterators::bitmask_combinations;
 pub use bitmask_iterators::bitmask_subsets;
+pub use bitmask_operations::i2powm1;
 pub use change_min_max::ChangeMinMax;
 pub use numeric_traits::Unsigned;
 pub use pop_if::PopIf;
diff --git a/libs/riff/src/numeric_traits.rs b/libs/riff/src/numeric_traits.rs
index 58843d81..76d65ec8 100644
--- a/libs/riff/src/numeric_traits.rs
+++ b/libs/riff/src/numeric_traits.rs
@@ -48,6 +48,8 @@ pub trait Unsigned:
     + ShrAssign<u32>
     + Not<Output = Self>
 {
+    const BITS: u32;
+    const MAX: Self;
     fn zero() -> Self;
     fn one() -> Self;
     fn wrapping_neg(self) -> Self;
@@ -59,6 +61,8 @@ pub trait Unsigned:
 macro_rules! impl_unsigned {
     ($($T:ty),* $(,)?) => {$(
         impl Unsigned for $T {
+            const BITS: u32 = <$T>::BITS;
+            const MAX: Self = <$T>::MAX;
             fn zero() -> Self { 0 }
             fn one() -> Self { 1 }
             fn wrapping_neg(self) -> Self { self.wrapping_neg() }