From 55acbe779450e3c9d5dd2d4aa8ae465c94a01077 Mon Sep 17 00:00:00 2001
From: akiraveliara <akiraveliara@outlook.com>
Date: Sat, 17 Aug 2024 14:42:04 +0200
Subject: [PATCH] append-only value list

---
 Directory.Build.props                         |  8 ++-
 src/Bundles/Bundles.csproj                    |  3 +-
 .../UnmanagedStack.cs}                        | 48 ++++---------
 .../ValueAppendList.Enumerator.cs             | 18 +++++
 .../ValueCollections/ValueAppendList.cs       | 68 +++++++++++++++++++
 tests/Bundles.Tests/Bundles.Tests.csproj      |  2 +-
 6 files changed, 108 insertions(+), 39 deletions(-)
 rename src/Bundles/{ValueCollections/ValueStack.cs => Unmanaged/UnmanagedStack.cs} (87%)
 create mode 100644 src/Bundles/ValueCollections/ValueAppendList.Enumerator.cs
 create mode 100644 src/Bundles/ValueCollections/ValueAppendList.cs

diff --git a/Directory.Build.props b/Directory.Build.props
index 5e69cd6..c838f5b 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -1,22 +1,26 @@
 <Project>
+
   <!-- build -->
   <PropertyGroup>
     <GenerateDocumentationFile>True</GenerateDocumentationFile>
     <LangVersion>preview</LangVersion>
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <Nullable>enable</Nullable>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <TreatWarningsAsErrors>True</TreatWarningsAsErrors>
+
     <!-- build and versioning setup -->
     <ManagePackageVersionsCentrally>True</ManagePackageVersionsCentrally>
     <NuGetAudit>true</NuGetAudit>
     <UseArtifactsOutput>true</UseArtifactsOutput>
+
     <!-- sourcelink -->
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
     <IncludeSymbols>true</IncludeSymbols>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
   </PropertyGroup>
+
   <!-- nuget -->
   <PropertyGroup>
     <Authors>akiraveliara, dotnet/corefxlab DictionarySlim contributors</Authors>
@@ -30,9 +34,11 @@
     <RepositoryType>git</RepositoryType>
     <RepositoryUrl>https://github.com/DSharpPlus/Bundles</RepositoryUrl>
   </PropertyGroup>
+
   <ItemGroup>
     <EmbeddedResource Include="../../LICENSE" Pack="true" PackagePath=""/>
     <EmbeddedResource Include="../../README.md" Pack="true" PackagePath=""/>
     <EmbeddedResource Include="../../img/logo.png" Pack="true" PackagePath=""/>
   </ItemGroup>
+  
 </Project>
\ No newline at end of file
diff --git a/src/Bundles/Bundles.csproj b/src/Bundles/Bundles.csproj
index f0e35ff..e1ab065 100644
--- a/src/Bundles/Bundles.csproj
+++ b/src/Bundles/Bundles.csproj
@@ -1,9 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <IsAotCompatible>true</IsAotCompatible>
     <OutputType>Library</OutputType>
     <PackageId>Bundles</PackageId>
-    <VersionPrefix>1.2.0</VersionPrefix>
+    <VersionPrefix>2.0.0</VersionPrefix>
   </PropertyGroup>
 </Project>
\ No newline at end of file
diff --git a/src/Bundles/ValueCollections/ValueStack.cs b/src/Bundles/Unmanaged/UnmanagedStack.cs
similarity index 87%
rename from src/Bundles/ValueCollections/ValueStack.cs
rename to src/Bundles/Unmanaged/UnmanagedStack.cs
index 5cd6d0f..b811366 100644
--- a/src/Bundles/ValueCollections/ValueStack.cs
+++ b/src/Bundles/Unmanaged/UnmanagedStack.cs
@@ -8,60 +8,50 @@
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
-namespace Bundles.ValueCollections;
+namespace Bundles.Unmanaged;
 
 /// <summary>
 /// Represents an allocation-free stack of unmanaged items. This stack cannot resize.
 /// </summary>
 /// <typeparam name="T">The item type of this collection.</typeparam>
 [DebuggerDisplay("Capacity = {Capacity}; Count = {Count}")]
-public unsafe ref struct ValueStack<T>
+public unsafe ref struct UnmanagedStack<T>
     where T : unmanaged
 {
     private readonly Span<T> items;
     private int count;
 
     /// <summary>
-    /// Creates a new, all-zero <see cref="ValueStack{T}"/>.
+    /// Creates a new, all-zero <see cref="UnmanagedStack{T}"/>.
     /// </summary>
-    public ValueStack()
+    public UnmanagedStack()
     {
         this.items = [];
         this.count = 0;
     }
 
     /// <summary>
-    /// Creates a new <see cref="ValueStack{T}"/>.
+    /// Creates a new <see cref="UnmanagedStack{T}"/>.
     /// </summary>
     /// <param name="memory">The backing memory for this instance.</param>
-    public ValueStack
-    (
-        Span<T> memory
-    )
+    public UnmanagedStack(Span<T> memory)
     {
         this.items = memory;
         this.count = 0;
     }
 
-    public ValueStack
-    (
-        T* memory,
-        nuint length
-    )
+    public UnmanagedStack(T* memory, nuint length)
     {
         this.items = MemoryMarshal.CreateSpan(ref Unsafe.AsRef<T>(memory), (int)length);
         this.count = 0;
     }
 
     /// <summary>
-    /// Creates a new <see cref="ValueStack{T}"/> by implicitly casting, enabling syntax such as
+    /// Creates a new <see cref="UnmanagedStack{T}"/> by implicitly casting, enabling syntax such as
     /// <c><![CDATA[ValueStack<int> stack = stackalloc int[4];]]></c>
     /// </summary>
     /// <param name="memory">The backing memory for this instance</param>
-    public static implicit operator ValueStack<T>
-    (
-        Span<T> memory
-    )
+    public static implicit operator UnmanagedStack<T>(Span<T> memory)
         => new(memory);
 
     /// <summary>
@@ -95,10 +85,7 @@ public readonly ref readonly T GetPinnableReference()
     /// </summary>
     /// <param name="item">The item to push to the stack.</param>
     /// <returns><c>true</c> to indicate success, <c>false</c> to indicate failure.</returns>
-    public bool TryPush
-    (
-        T item
-    )
+    public bool TryPush(T item)
     {
         if (this.count == this.items.Length)
         {
@@ -114,10 +101,7 @@ T item
     /// </summary>
     /// <param name="item">The item popped from the stack.</param>
     /// <returns><c>true</c> to indicate success, <c>false</c> to indicate failure.</returns>
-    public bool TryPop
-    (
-        out T item
-    )
+    public bool TryPop(out T item)
     {
         if (this.count == 0)
         {
@@ -134,10 +118,7 @@ out T item
     /// </summary>
     /// <param name="item">The item peeked from the stack.</param>
     /// <returns><c>true</c> to indicate success, <c>false</c> to indicate failure.</returns>
-    public readonly bool TryPeek
-    (
-        out T item
-    )
+    public readonly bool TryPeek(out T item)
     {
         if (this.count == 0)
         {
@@ -153,10 +134,7 @@ out T item
     /// Pushes a new item to the stack.
     /// </summary>
     /// <exception cref="InvalidOperationException">Thrown if the stack was full.</exception>
-    public void Push
-    (
-        T item
-    )
+    public void Push(T item)
     {
         if (!this.TryPush(item))
         {
diff --git a/src/Bundles/ValueCollections/ValueAppendList.Enumerator.cs b/src/Bundles/ValueCollections/ValueAppendList.Enumerator.cs
new file mode 100644
index 0000000..be050f4
--- /dev/null
+++ b/src/Bundles/ValueCollections/ValueAppendList.Enumerator.cs
@@ -0,0 +1,18 @@
+// This Source Code form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+namespace Bundles.ValueCollections;
+
+partial record struct ValueAppendList<T>
+{
+    public struct Enumerator(ValueAppendList<T> list)
+    {
+        private int index;
+
+        public ref readonly T Current => ref list[this.index];
+
+        public bool MoveNext() 
+            => ++this.index != list.Count;
+    }
+}
diff --git a/src/Bundles/ValueCollections/ValueAppendList.cs b/src/Bundles/ValueCollections/ValueAppendList.cs
new file mode 100644
index 0000000..6899892
--- /dev/null
+++ b/src/Bundles/ValueCollections/ValueAppendList.cs
@@ -0,0 +1,68 @@
+// This Source Code form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+using System.Buffers;
+
+namespace Bundles.ValueCollections;
+
+/// <summary>
+/// A value-type list type that can only be modified by appending, never by removing.
+/// </summary>
+/// <typeparam name="T">The element type controlled by this list.</typeparam>
+public partial record struct ValueAppendList<T>
+{
+    private T[] buffer;
+    private int index;
+
+    /// <summary>
+    /// Gets a readonly reference to the element at the specified index.
+    /// </summary>
+    public readonly ref readonly T this[int index] => ref this.buffer[index];
+
+    /// <summary>
+    /// Gets the current capacity of this list.
+    /// </summary>
+    public readonly int Capacity => this.buffer.Length;
+
+    /// <summary>
+    /// Gets the element count of this list.
+    /// </summary>
+    public readonly int Count => this.index + 1;
+
+    /// <summary>
+    /// Adds an element to the list, returning a readonly reference to the newly added element.
+    /// </summary>
+    public ref readonly T Add(T value)
+    {
+        if (++this.index == buffer.Length)
+        {
+            this.ResizeBuffer();
+        }
+
+        this.buffer[this.index] = value;
+        return ref this.buffer[this.index];
+    }
+
+    /// <summary>
+    /// Gets an enumerator over the present structure.
+    /// </summary>
+    /// <returns></returns>
+    public readonly Enumerator GetEnumerator()
+        => new(this);
+
+    private void ResizeBuffer()
+    {
+        int newLength = this.buffer.Length * 2;
+        T[] newBuffer = typeof(T).IsPrimitive ? ArrayPool<T>.Shared.Rent(newLength) : new T[newLength];
+
+        this.buffer.CopyTo(newBuffer, 0);
+
+        if (typeof(T).IsPrimitive)
+        {
+            ArrayPool<T>.Shared.Return(this.buffer);
+        }
+
+        this.buffer = newBuffer;
+    }
+}
diff --git a/tests/Bundles.Tests/Bundles.Tests.csproj b/tests/Bundles.Tests/Bundles.Tests.csproj
index 7da1e3b..ebd1862 100644
--- a/tests/Bundles.Tests/Bundles.Tests.csproj
+++ b/tests/Bundles.Tests/Bundles.Tests.csproj
@@ -4,7 +4,7 @@
     <IsPackable>false</IsPackable>
     <IsTestProject>true</IsTestProject>
     <Nullable>enable</Nullable>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <NoWarn>$(NoWarn);CA1869</NoWarn>
   </PropertyGroup>