From d55931ed3d39c03c264300baf7f0df582e346d1f Mon Sep 17 00:00:00 2001
From: Nagata Kana <ngtkana@gmail.com>
Date: Tue, 10 Dec 2024 19:30:28 +0900
Subject: [PATCH] fix riff

---
 libs/riff/src/bitmask_iterators.rs  | 12 ++++++------
 libs/riff/src/bitmask_operations.rs | 10 ++++++++--
 libs/riff/src/numeric_traits.rs     |  8 ++++----
 3 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/libs/riff/src/bitmask_iterators.rs b/libs/riff/src/bitmask_iterators.rs
index a6c08fde..3f6c7471 100644
--- a/libs/riff/src/bitmask_iterators.rs
+++ b/libs/riff/src/bitmask_iterators.rs
@@ -16,7 +16,7 @@ pub fn bitmask_combinations<T: Unsigned>(n: u32, k: u32) -> BitmaskCombinations<
     assert!(k < T::bit_length() && k < T::bit_length());
     BitmaskCombinations {
         n,
-        bs: (T::one() << k) - T::one(),
+        bs: (T::ONE << k) - T::ONE,
     }
 }
 
@@ -29,12 +29,12 @@ impl<T: Unsigned> Iterator for BitmaskCombinations<T> {
     type Item = T;
 
     fn next(&mut self) -> Option<Self::Item> {
-        if (T::one() << self.n) <= self.bs {
+        if (T::ONE << self.n) <= self.bs {
             return None;
         }
         let res = Some(self.bs);
-        self.bs = if self.bs == T::zero() {
-            T::one() << self.n
+        self.bs = if self.bs == T::ZERO {
+            T::ONE << self.n
         } else {
             let x = self.bs & self.bs.wrapping_neg();
             let y = self.bs + x;
@@ -78,10 +78,10 @@ impl<T: Unsigned> Iterator for BitmaskSubsets<T> {
             return None;
         }
         let res = Some(self.bs ^ self.full);
-        if self.bs == T::zero() {
+        if self.bs == T::ZERO {
             self.finished = true;
         } else {
-            self.bs -= T::one();
+            self.bs -= T::ONE;
             self.bs &= self.full;
         }
         res
diff --git a/libs/riff/src/bitmask_operations.rs b/libs/riff/src/bitmask_operations.rs
index 082b44a2..dfb35d39 100644
--- a/libs/riff/src/bitmask_operations.rs
+++ b/libs/riff/src/bitmask_operations.rs
@@ -4,12 +4,18 @@ use crate::Unsigned;
 ///
 /// # Examples
 /// ```
-/// use crate::i2powm1;
+/// use riff::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);
+/// assert_eq!(i2powm1::<u32>(31), 0x7FFF_FFFF);
+/// assert_eq!(i2powm1::<u32>(32), 0xFFFF_FFFF);
 /// ```
 pub fn i2powm1<T: Unsigned>(n: u32) -> T {
-    T::MAX >> (T::BITS - n)
+    if n == T::bit_length() {
+        T::MAX
+    } else {
+        (T::ONE << n) - T::ONE
+    }
 }
diff --git a/libs/riff/src/numeric_traits.rs b/libs/riff/src/numeric_traits.rs
index 76d65ec8..80be872d 100644
--- a/libs/riff/src/numeric_traits.rs
+++ b/libs/riff/src/numeric_traits.rs
@@ -50,8 +50,8 @@ pub trait Unsigned:
 {
     const BITS: u32;
     const MAX: Self;
-    fn zero() -> Self;
-    fn one() -> Self;
+    const ZERO: Self;
+    const ONE: Self;
     fn wrapping_neg(self) -> Self;
     fn bit_length() -> u32 {
         size_of::<Self>() as u32 * 8
@@ -63,8 +63,8 @@ macro_rules! impl_unsigned {
         impl Unsigned for $T {
             const BITS: u32 = <$T>::BITS;
             const MAX: Self = <$T>::MAX;
-            fn zero() -> Self { 0 }
-            fn one() -> Self { 1 }
+            const ZERO: Self = 0;
+            const ONE: Self = 1;
             fn wrapping_neg(self) -> Self { self.wrapping_neg() }
         }
     )*}