ArrayBuilder

A lightweight, pool-backed builder for constructing arrays. Dispose returns the backing buffer to the pool.

C# Signature

internal readonly struct ArrayBuilder<T> : System.IDisposable

Examples

The following example demonstrates how to add, remove, consume, and dispose the array builder.

C#

using System;
using System.Reflection;
using Hertzole.SourceGen;

public class MethodCaller
{
    public void CallMethods(object target)
    {
        // Must dispose when the builder is no longer needed.
        using ArrayBuilder<MethodInfo> builder = new ArrayBuilder<MethodInfo>();

        CollectMethods(target, builder);
        CallCollectedMethods(target, builder.AsSpan());
    }

    private void CollectMethods(object target, ArrayBuilder<MethodInfo> builder)
    {
        Type type = target.GetType();
        MethodInfo[] methods = type.GetMethods(BindingFlags.Public | BindingFlags.Instance);
        builder.AddRange(methods);
    }

    private void CallCollectedMethods(object target, ReadOnlySpan<MethodInfo> methods)
    {
        foreach (MethodInfo method in methods)
        {
            // Methods like object.Equals(object) take parameters, so skip them.
            if (method.GetParameters().Length == 0)
            {
                method.Invoke(target, null);
            }
        }
    }
}

The following example shows how you can use ArrayBuilder to quickly create strings.

C#

using System;
using Hertzole.SourceGen;

public class Announcer
{
    public void AnnounceName(int playerIndex)
    {
        // Must dispose when the builder is no longer needed.
        using ArrayBuilder<char> builder = new ArrayBuilder<char>();
        builder.AddRange("Player ");
        builder.AddRange(playerIndex.ToString());

        // ToString on ArrayBuilder<char> returns a constructed string.
        Console.WriteLine($"Welcome, {builder.ToString()}!");
    }
}

Constructors

ArrayBuilder()

Creates a new ArrayBuilder<T> with a default initial capacity.

C# Signature

public ArrayBuilder();

ArrayBuilder(int)

Creates a new ArrayBuilder<T> with the specified initial capacity.

C# Signature

public ArrayBuilder(int capacity);

capacity

The minimum capacity of the backing array.

ArrayBuilder(ReadOnlySpan<T>)

Creates a new ArrayBuilder<T> initialized with the specified items.

C# Signature

public ArrayBuilder(ReadOnlySpan<T> items);

items

The items to initialize the builder with.

Properties

Count

C# Signature

public int Count { get; }

Item[]

C# Signature

public T this[int index] { get; set; }

Methods

Add(T)

Adds an item to the builder.

C# Signature

public void Add(T item);

item

The item to add.

AddRange(ReadOnlySpan<T>)

Adds a range of items to the builder.

C# Signature

public void AddRange(ReadOnlySpan<T> items);

items

The items to add.

AddRange(IEnumerable<T>)

Adds a range of items to the builder.

C# Signature

public void AddRange(IEnumerable<T> items);

items

The items to add.

AsSpan()

Returns a read-only span over the builder’s contents.

C# Signature

public ReadOnlySpan<T> AsSpan();

Returns

A read-only span over the builder’s contents.

Clear()

Removes all items from the builder.

C# Signature

public void Clear();

Contains(T)

Checks if the specified item is added to the array.

C# Signature

public bool Contains(T item);

item

The item to check for.

Returns

true if the item was found; otherwise false.

CopyTo(T[], int)

Copies the contents of this array builder to the specified array.

C# Signature

public void CopyTo(T[] destination, int destinationIndex);

destination

The array to copy the contents to.

destinationIndex

The index into the destination array to which the first copied element is written.

Dispose()

Returns the backing buffer to the pool.

C# Signature

public void Dispose();

IndexOf(T)

Gets the index of an item in the array.

C# Signature

public int IndexOf(T item);

item

The item to check for.

Returns

The index of the item in the array, or -1 if the item was not found.

Insert(int, T)

Inserts an item into the specified index and shifts the items after it to the right.

C# Signature

public void Insert(int index, T item);

index

The zero-based index at which to insert the item.

item

The item to insert.

InsertRange(int, ReadOnlySpan<T>)

Inserts multiple items into the specified index and shifts the items after the newly inserted items to the right.

C# Signature

public void InsertRange(int index, ReadOnlySpan<T> items);

index

The zero-based index at which to insert the items.

items

The items to insert.

InsertRange(int, IEnumerable<T>)

Inserts multiple items into the specified index and shifts the items after the newly inserted items to the right.

C# Signature

public void InsertRange(int index, IEnumerable<T> items);

index

The zero-based index at which to insert the items.

items

The items to insert.

Remove(T)

Removes the first occurrence of the specified item from the builder.

C# Signature

public bool Remove(T item);

item

The item to remove.

Returns

true if the item was found and removed; otherwise false.

RemoveAt(int)

Removes the item at the specified index.

C# Signature

public void RemoveAt(int index);

index

The zero-based index of the item to remove.

RemoveRange(int, int)

Removes a range of items, starting at the specified start index and removes the specified count.

C# Signature

public void RemoveRange(int start, int count);

start

The zero-based index of the first item to remove.

count

The number of items to remove.

ReplaceAll(T, T)

Replaces all values of the specified value in the array with the new specified value.

C# Signature

public void ReplaceAll(T toReplace, T newValue);

toReplace

The value to replace.

newValue

The new value to insert.

ToArray()

Returns a new array with the builder’s contents.

C# Signature

public T[] ToArray();

Returns

A new array with the builder’s contents.

ToImmutableArray()

Returns a new immutable array with the builder’s contents.

C# Signature

public ImmutableArray<T> ToImmutableArray();

Returns

A new immutable array with the builder’s contents.

ToString()

For ArrayBuilder<char>, returns a new string that represents the builder’s contents. Otherwise, returns a string with the name of the type and the number of elements.

C# Signature

public override string ToString();