From 6a8f7df5d12316166de405d9410ca9988a58430b Mon Sep 17 00:00:00 2001
From: Kristof <kristofr@gmail.com>
Date: Fri, 28 Mar 2025 14:15:37 +0100
Subject: [PATCH] added from_array that allows you initialize an entire array
 of values with fairly compact syntax

---
 deranged/src/lib.rs   | 22 ++++++++++++++++++++++
 deranged/src/tests.rs | 19 +++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/deranged/src/lib.rs b/deranged/src/lib.rs
index 91b562e..c7fa493 100644
--- a/deranged/src/lib.rs
+++ b/deranged/src/lib.rs
@@ -952,6 +952,28 @@ macro_rules! impl_ranged {
                     ) }
                 }
             }
+
+            /// Convert an array of plain integers into an array of RangedX. Useful for const initialization
+            /// when you have a lookup table with lots of values that are all in range.
+            /// eg
+            /// const CONST_ARRAY : [RangedU8<1,10>;10] = RangedU8<1,10>::from_array([1,2,3,4,5,6,7,8,9,10]).unwrap();
+            ///
+            /// Returns None if any of the values are out of range, so the compile will fail at the unwrap if
+            /// any of the values are out of range.
+            pub const fn from_array<const N: usize>(a: [$internal; N]) -> Option<[Self; N]> {
+                let mut r = [Self::MIN; N];
+                let mut i = 0;
+                while i < N {
+                    if let Some(x) = Self::new(a[i]) {
+                        r[i] = x;
+                    } else {
+                        return None;
+                    }
+
+                    i += 1;
+                }
+                Some(r)
+            }
         }
 
         impl<const MIN: $internal, const MAX: $internal> $optional_type<MIN, MAX> {
diff --git a/deranged/src/tests.rs b/deranged/src/tests.rs
index 3ea7530..785caa1 100644
--- a/deranged/src/tests.rs
+++ b/deranged/src/tests.rs
@@ -601,6 +601,25 @@ macro_rules! tests {
             assert_eq!($t::<5, 10>::try_from(11), Err(TryFromIntError));
         )*}
 
+        #[test]
+        fn from_array() {$(
+            {
+                // Create array of 3 elements that's a const
+                const MYARR : [$t::<5, 10>; 3] = $t::<5, 10>::from_array([5,6,10]).unwrap();
+                const EXPECTED_RESULT : [$t::<5,10>;3] = [
+                    $t::<5,10>::new_static::<5>(),
+                    $t::<5,10>::new_static::<6>(),
+                    $t::<5,10>::new_static::<10>()];
+
+                assert_eq!(MYARR, EXPECTED_RESULT);
+            }
+
+            // if any element is out of range, the whole array is None
+            assert_eq!(
+                $t::<5, 10>::from_array([5,6,11]),
+                None);
+        )*}
+
         #[test]
         fn from_str() {$(
             assert_eq!("10".parse::<$t<5, 10>>(), Ok($t::<5, 10>::MAX));