Fix bug where hash table perfect wouldn't reorder values

Author: Genbox

Src/FastData.Generator.CPlusPlus.Tests/Features/ObjectSupportTest-HashTablePerfectStructure_Int32_3_complex.verified.txt

@@ -23,7 +23,7 @@ class HashTablePerfectStructure_Int32_3_complex final {
         : key(key), value(value) {}
     };
     inline static const std::array<e, 3> entries = {
-        e(3, new Person(1, U"Bob", new Person(4, U"Anna", nullptr))), e(1, new Person(2, U"Billy", nullptr)), e(2, new Person(3, U"Bibi", nullptr))
+        e(3, new Person(3, U"Bibi", nullptr)), e(1, new Person(1, U"Bob", new Person(4, U"Anna", nullptr))), e(2, new Person(2, U"Billy", nullptr))
     };
 
     static constexpr uint64_t get_hash(const int32_t value) noexcept

Src/FastData.Generator.CPlusPlus.Tests/Features/ObjectSupportTest-HashTablePerfectStructure_Int32_3_simple.verified.txt

@@ -16,7 +16,7 @@ class HashTablePerfectStructure_Int32_3_simple final {
         : key(key), value(value) {}
     };
     inline static const std::array<e, 3> entries = {
-        e(3, 1), e(1, 2), e(2, 3)
+        e(3, 3), e(1, 1), e(2, 2)
     };
 
     static constexpr uint64_t get_hash(const int32_t value) noexcept

Src/FastData.Generator.CSharp.Tests/Features/ObjectSupportTest-HashTablePerfectStructure_Int32_3_complex.verified.txt

@@ -36,7 +36,7 @@ private struct E
     }
 }
     private static readonly E[] _entries = {
-        new E(3, new Person(1, "Bob", new Person(4, "Anna", null))), new E(1, new Person(2, "Billy", null)), new E(2, new Person(3, "Bibi", null))
+        new E(3, new Person(3, "Bibi", null)), new E(1, new Person(1, "Bob", new Person(4, "Anna", null))), new E(2, new Person(2, "Billy", null))
     };
 
 

Src/FastData.Generator.CSharp.Tests/Features/ObjectSupportTest-HashTablePerfectStructure_Int32_3_simple.verified.txt

@@ -23,7 +23,7 @@ private struct E
     }
 }
     private static readonly E[] _entries = {
-        new E(3, 1), new E(1, 2), new E(2, 3)
+        new E(3, 3), new E(1, 1), new E(2, 2)
     };
 
 

Src/FastData.Generator.Rust.Tests/Features/ObjectSupportTest-HashTablePerfectStructure_Int32_3_complex.verified.txt

@@ -29,7 +29,7 @@ impl Person {
 impl HashTablePerfectStructure_Int32_3_complex {
 
 const ENTRIES: [e; 3] = [
-            e::new(3, &Person::new(1, "Bob", Some(&Person::new(4, "Anna", None)))), e::new(1, &Person::new(2, "Billy", None)), e::new(2, &Person::new(3, "Bibi", None))
+            e::new(3, &Person::new(3, "Bibi", None)), e::new(1, &Person::new(1, "Bob", Some(&Person::new(4, "Anna", None)))), e::new(2, &Person::new(2, "Billy", None))
 ];
 
     #[inline(always)]

Src/FastData.Generator.Rust.Tests/Features/ObjectSupportTest-HashTablePerfectStructure_Int32_3_simple.verified.txt

@@ -19,7 +19,7 @@ impl e {
 impl HashTablePerfectStructure_Int32_3_simple {
 
 const ENTRIES: [e; 3] = [
-            e::new(3, 1), e::new(1, 2), e::new(2, 3)
+            e::new(3, 3), e::new(1, 1), e::new(2, 2)
 ];
 
     #[inline(always)]

Src/FastData/Internal/Structures/HashTablePerfectStructure.cs

@@ -17,11 +17,18 @@ public HashTablePerfectContext<TKey, TValue> Create(TKey[] keys, TValue[]? value
 
         ulong[] hashCodes = hashData.HashCodes;
         KeyValuePair<TKey, ulong>[] pairs = new KeyValuePair<TKey, ulong>[size];
+        TValue[]? denseValues = values == null ? null : new TValue[size];
 
         //We need to reorder the data to match hashes
         for (int i = 0; i < keys.Length; i++)
-            pairs[hashCodes[i] % size] = new KeyValuePair<TKey, ulong>(keys[i], hashCodes[i]);
+        {
+            ulong index = hashCodes[i] % size;
+            pairs[index] = new KeyValuePair<TKey, ulong>(keys[i], hashCodes[i]);
 
-        return new HashTablePerfectContext<TKey, TValue>(pairs, !keyType.IsIdentityHash(), values);
+            if (denseValues != null)
+                denseValues[index] = values![i];
+        }
+
+        return new HashTablePerfectContext<TKey, TValue>(pairs, !keyType.IsIdentityHash(), denseValues);
     }
 }