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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
namespace System.Collections.Immutable
{
/// <summary>
/// An immutable sorted dictionary implementation.
/// </summary>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <typeparam name="TValue">The type of the value.</typeparam>
[DebuggerDisplay("Count = {Count}")]
[DebuggerTypeProxy(typeof(ImmutableDictionaryDebuggerProxy<,>))]
public sealed partial class ImmutableSortedDictionary<TKey, TValue> : IImmutableDictionary<TKey, TValue>, ISortKeyCollection<TKey>, IDictionary<TKey, TValue>, IDictionary
{
/// <summary>
/// An empty sorted dictionary with default sort and equality comparers.
/// </summary>
public static readonly ImmutableSortedDictionary<TKey, TValue> Empty = new ImmutableSortedDictionary<TKey, TValue>();
/// <summary>
/// The root node of the AVL tree that stores this map.
/// </summary>
private readonly Node _root;
/// <summary>
/// The number of elements in the set.
/// </summary>
private readonly int _count;
/// <summary>
/// The comparer used to sort keys in this map.
/// </summary>
private readonly IComparer<TKey> _keyComparer;
/// <summary>
/// The comparer used to detect equivalent values in this map.
/// </summary>
private readonly IEqualityComparer<TValue> _valueComparer;
/// <summary>
/// Initializes a new instance of the <see cref="ImmutableSortedDictionary{TKey, TValue}"/> class.
/// </summary>
/// <param name="keyComparer">The key comparer.</param>
/// <param name="valueComparer">The value comparer.</param>
internal ImmutableSortedDictionary(IComparer<TKey>? keyComparer = null, IEqualityComparer<TValue>? valueComparer = null)
{
_keyComparer = keyComparer ?? Comparer<TKey>.Default;
_valueComparer = valueComparer ?? EqualityComparer<TValue>.Default;
_root = Node.EmptyNode;
}
/// <summary>
/// Initializes a new instance of the <see cref="ImmutableSortedDictionary{TKey, TValue}"/> class.
/// </summary>
/// <param name="root">The root of the tree containing the contents of the map.</param>
/// <param name="count">The number of elements in this map.</param>
/// <param name="keyComparer">The key comparer.</param>
/// <param name="valueComparer">The value comparer.</param>
private ImmutableSortedDictionary(Node root, int count, IComparer<TKey> keyComparer, IEqualityComparer<TValue> valueComparer)
{
Requires.NotNull(root, nameof(root));
Requires.Range(count >= 0, nameof(count));
Requires.NotNull(keyComparer, nameof(keyComparer));
Requires.NotNull(valueComparer, nameof(valueComparer));
root.Freeze();
_root = root;
_count = count;
_keyComparer = keyComparer;
_valueComparer = valueComparer;
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public ImmutableSortedDictionary<TKey, TValue> Clear()
{
return _root.IsEmpty ? this : Empty.WithComparers(_keyComparer, _valueComparer);
}
#region IImmutableMap<TKey, TValue> Properties
/// <summary>
/// Gets the value comparer used to determine whether values are equal.
/// </summary>
public IEqualityComparer<TValue> ValueComparer
{
get { return _valueComparer; }
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public bool IsEmpty
{
get { return _root.IsEmpty; }
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public int Count
{
get { return _count; }
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public IEnumerable<TKey> Keys
{
get { return _root.Keys; }
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public IEnumerable<TValue> Values
{
get { return _root.Values; }
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
IImmutableDictionary<TKey, TValue> IImmutableDictionary<TKey, TValue>.Clear()
{
return this.Clear();
}
#endregion
#region IDictionary<TKey, TValue> Properties
/// <summary>
/// Gets the keys.
/// </summary>
ICollection<TKey> IDictionary<TKey, TValue>.Keys
{
get { return new KeysCollectionAccessor<TKey, TValue>(this); }
}
/// <summary>
/// Gets the values.
/// </summary>
ICollection<TValue> IDictionary<TKey, TValue>.Values
{
get { return new ValuesCollectionAccessor<TKey, TValue>(this); }
}
#endregion
#region ICollection<KeyValuePair<TKey, TValue>> Properties
bool ICollection<KeyValuePair<TKey, TValue>>.IsReadOnly
{
get { return true; }
}
#endregion
#region ISortKeyCollection<TKey> Properties
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public IComparer<TKey> KeyComparer
{
get { return _keyComparer; }
}
#endregion
/// <summary>
/// Gets the root node (for testing purposes).
/// </summary>
internal Node Root
{
get { return _root; }
}
#region IImmutableMap<TKey, TValue> Indexers
/// <summary>
/// Gets the <typeparamref name="TValue"/> with the specified key.
/// </summary>
public TValue this[TKey key]
{
get
{
Requires.NotNullAllowStructs(key, nameof(key));
TValue? value;
if (!this.TryGetValue(key, out value))
{
ThrowHelper.ThrowKeyNotFoundException(key);
}
return value;
}
}
/// <summary>
/// Returns a read-only reference to the value associated with the provided key.
/// </summary>
/// <exception cref="KeyNotFoundException">If the key is not present.</exception>
public ref readonly TValue ValueRef(TKey key)
{
Requires.NotNullAllowStructs(key, nameof(key));
return ref _root.ValueRef(key, _keyComparer);
}
#endregion
/// <summary>
/// Gets or sets the <typeparamref name="TValue"/> with the specified key.
/// </summary>
TValue IDictionary<TKey, TValue>.this[TKey key]
{
get { return this[key]; }
set { throw new NotSupportedException(); }
}
#region Public methods
/// <summary>
/// Creates a collection with the same contents as this collection that
/// can be efficiently mutated across multiple operations using standard
/// mutable interfaces.
/// </summary>
/// <remarks>
/// This is an O(1) operation and results in only a single (small) memory allocation.
/// The mutable collection that is returned is *not* thread-safe.
/// </remarks>
public Builder ToBuilder()
{
// We must not cache the instance created here and return it to various callers.
// Those who request a mutable collection must get references to the collection
// that version independently of each other.
return new Builder(this);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public ImmutableSortedDictionary<TKey, TValue> Add(TKey key, TValue value)
{
Requires.NotNullAllowStructs(key, nameof(key));
ImmutableSortedDictionary<TKey, TValue>.Node result = _root.Add(key, value, _keyComparer, _valueComparer, out _);
return this.Wrap(result, _count + 1);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public ImmutableSortedDictionary<TKey, TValue> SetItem(TKey key, TValue value)
{
Requires.NotNullAllowStructs(key, nameof(key));
bool replacedExistingValue;
ImmutableSortedDictionary<TKey, TValue>.Node result = _root.SetItem(key, value, _keyComparer, _valueComparer, out replacedExistingValue, out _);
return this.Wrap(result, replacedExistingValue ? _count : _count + 1);
}
/// <summary>
/// Applies a given set of key=value pairs to an immutable dictionary, replacing any conflicting keys in the resulting dictionary.
/// </summary>
/// <param name="items">The key=value pairs to set on the map. Any keys that conflict with existing keys will overwrite the previous values.</param>
/// <returns>An immutable dictionary.</returns>
public ImmutableSortedDictionary<TKey, TValue> SetItems(IEnumerable<KeyValuePair<TKey, TValue>> items)
{
Requires.NotNull(items, nameof(items));
return this.AddRange(items, overwriteOnCollision: true, avoidToSortedMap: false);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public ImmutableSortedDictionary<TKey, TValue> AddRange(IEnumerable<KeyValuePair<TKey, TValue>> items)
{
Requires.NotNull(items, nameof(items));
return this.AddRange(items, overwriteOnCollision: false, avoidToSortedMap: false);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public ImmutableSortedDictionary<TKey, TValue> Remove(TKey value)
{
Requires.NotNullAllowStructs(value, nameof(value));
ImmutableSortedDictionary<TKey, TValue>.Node result = _root.Remove(value, _keyComparer, out _);
return this.Wrap(result, _count - 1);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public ImmutableSortedDictionary<TKey, TValue> RemoveRange(IEnumerable<TKey> keys)
{
Requires.NotNull(keys, nameof(keys));
ImmutableSortedDictionary<TKey, TValue>.Node result = _root;
int count = _count;
foreach (TKey key in keys)
{
bool mutated;
ImmutableSortedDictionary<TKey, TValue>.Node newResult = result.Remove(key, _keyComparer, out mutated);
if (mutated)
{
result = newResult;
count--;
}
}
return this.Wrap(result, count);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public ImmutableSortedDictionary<TKey, TValue> WithComparers(IComparer<TKey>? keyComparer, IEqualityComparer<TValue>? valueComparer)
{
keyComparer ??= Comparer<TKey>.Default;
valueComparer ??= EqualityComparer<TValue>.Default;
if (keyComparer == _keyComparer)
{
if (valueComparer == _valueComparer)
{
return this;
}
else
{
// When the key comparer is the same but the value comparer is different, we don't need a whole new tree
// because the structure of the tree does not depend on the value comparer.
// We just need a new root node to store the new value comparer.
return new ImmutableSortedDictionary<TKey, TValue>(_root, _count, _keyComparer, valueComparer);
}
}
else
{
// A new key comparer means the whole tree structure could change. We must build a new one.
var result = new ImmutableSortedDictionary<TKey, TValue>(Node.EmptyNode, 0, keyComparer, valueComparer);
result = result.AddRange(this, overwriteOnCollision: false, avoidToSortedMap: true);
return result;
}
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public ImmutableSortedDictionary<TKey, TValue> WithComparers(IComparer<TKey>? keyComparer)
{
return this.WithComparers(keyComparer, _valueComparer);
}
/// <summary>
/// Determines whether the <see cref="ImmutableSortedDictionary{TKey, TValue}"/>
/// contains an element with the specified value.
/// </summary>
/// <param name="value">
/// The value to locate in the <see cref="ImmutableSortedDictionary{TKey, TValue}"/>.
/// The value can be null for reference types.
/// </param>
/// <returns>
/// true if the <see cref="ImmutableSortedDictionary{TKey, TValue}"/> contains
/// an element with the specified value; otherwise, false.
/// </returns>
public bool ContainsValue(TValue value)
{
return _root.ContainsValue(value, _valueComparer);
}
#endregion
#region IImmutableDictionary<TKey, TValue> Methods
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
IImmutableDictionary<TKey, TValue> IImmutableDictionary<TKey, TValue>.Add(TKey key, TValue value)
{
return this.Add(key, value);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
IImmutableDictionary<TKey, TValue> IImmutableDictionary<TKey, TValue>.SetItem(TKey key, TValue value)
{
return this.SetItem(key, value);
}
/// <summary>
/// Applies a given set of key=value pairs to an immutable dictionary, replacing any conflicting keys in the resulting dictionary.
/// </summary>
/// <param name="items">The key=value pairs to set on the map. Any keys that conflict with existing keys will overwrite the previous values.</param>
/// <returns>An immutable dictionary.</returns>
IImmutableDictionary<TKey, TValue> IImmutableDictionary<TKey, TValue>.SetItems(IEnumerable<KeyValuePair<TKey, TValue>> items)
{
return this.SetItems(items);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
IImmutableDictionary<TKey, TValue> IImmutableDictionary<TKey, TValue>.AddRange(IEnumerable<KeyValuePair<TKey, TValue>> pairs)
{
return this.AddRange(pairs);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
IImmutableDictionary<TKey, TValue> IImmutableDictionary<TKey, TValue>.RemoveRange(IEnumerable<TKey> keys)
{
return this.RemoveRange(keys);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
IImmutableDictionary<TKey, TValue> IImmutableDictionary<TKey, TValue>.Remove(TKey key)
{
return this.Remove(key);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public bool ContainsKey(TKey key)
{
Requires.NotNullAllowStructs(key, nameof(key));
return _root.ContainsKey(key, _keyComparer);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public bool Contains(KeyValuePair<TKey, TValue> pair)
{
return _root.Contains(pair, _keyComparer, _valueComparer);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public bool TryGetValue(TKey key, [MaybeNullWhen(false)] out TValue value)
{
Requires.NotNullAllowStructs(key, nameof(key));
return _root.TryGetValue(key, _keyComparer, out value!);
}
/// <summary>
/// See the <see cref="IImmutableDictionary{TKey, TValue}"/> interface.
/// </summary>
public bool TryGetKey(TKey equalKey, out TKey actualKey)
{
Requires.NotNullAllowStructs(equalKey, nameof(equalKey));
return _root.TryGetKey(equalKey, _keyComparer, out actualKey);
}
#endregion
#region IDictionary<TKey, TValue> Methods
/// <summary>
/// Adds an element with the provided key and value to the <see cref="IDictionary{TKey, TValue}"/>.
/// </summary>
/// <param name="key">The object to use as the key of the element to add.</param>
/// <param name="value">The object to use as the value of the element to add.</param>
/// <exception cref="ArgumentNullException"><paramref name="key"/> is null.
/// </exception>
/// <exception cref="ArgumentException">
/// An element with the same key already exists in the <see cref="IDictionary{TKey, TValue}"/>.
/// </exception>
/// <exception cref="NotSupportedException">
/// The <see cref="IDictionary{TKey, TValue}"/> is read-only.
/// </exception>
void IDictionary<TKey, TValue>.Add(TKey key, TValue value)
{
throw new NotSupportedException();
}
/// <summary>
/// Removes the element with the specified key from the <see cref="IDictionary{TKey, TValue}"/>.
/// </summary>
/// <param name="key">The key of the element to remove.</param>
/// <returns>
/// true if the element is successfully removed; otherwise, false. This method also returns false if <paramref name="key"/> was not found in the original <see cref="IDictionary{TKey, TValue}"/>.
/// </returns>
/// <exception cref="ArgumentNullException"><paramref name="key"/> is null.
/// </exception>
/// <exception cref="NotSupportedException">
/// The <see cref="IDictionary{TKey, TValue}"/> is read-only.
/// </exception>
bool IDictionary<TKey, TValue>.Remove(TKey key)
{
throw new NotSupportedException();
}
#endregion
#region ICollection<KeyValuePair<TKey, TValue>> Methods
void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> item)
{
throw new NotSupportedException();
}
void ICollection<KeyValuePair<TKey, TValue>>.Clear()
{
throw new NotSupportedException();
}
bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> item)
{
throw new NotSupportedException();
}
void ICollection<KeyValuePair<TKey, TValue>>.CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
{
Requires.NotNull(array, nameof(array));
Requires.Range(arrayIndex >= 0, nameof(arrayIndex));
Requires.Range(array.Length >= arrayIndex + this.Count, nameof(arrayIndex));
foreach (KeyValuePair<TKey, TValue> item in this)
{
array[arrayIndex++] = item;
}
}
#endregion
#region IDictionary Properties
/// <summary>
/// Gets a value indicating whether the <see cref="IDictionary"/> object has a fixed size.
/// </summary>
/// <returns>true if the <see cref="IDictionary"/> object has a fixed size; otherwise, false.</returns>
bool IDictionary.IsFixedSize
{
get { return true; }
}
/// <summary>
/// Gets a value indicating whether the <see cref="ICollection{T}"/> is read-only.
/// </summary>
/// <returns>true if the <see cref="ICollection{T}"/> is read-only; otherwise, false.
/// </returns>
bool IDictionary.IsReadOnly
{
get { return true; }
}
/// <summary>
/// Gets an <see cref="ICollection{T}"/> containing the keys of the <see cref="IDictionary{TKey, TValue}"/>.
/// </summary>
/// <returns>
/// An <see cref="ICollection{T}"/> containing the keys of the object that implements <see cref="IDictionary{TKey, TValue}"/>.
/// </returns>
ICollection IDictionary.Keys
{
get { return new KeysCollectionAccessor<TKey, TValue>(this); }
}
/// <summary>
/// Gets an <see cref="ICollection{T}"/> containing the values in the <see cref="IDictionary{TKey, TValue}"/>.
/// </summary>
/// <returns>
/// An <see cref="ICollection{T}"/> containing the values in the object that implements <see cref="IDictionary{TKey, TValue}"/>.
/// </returns>
ICollection IDictionary.Values
{
get { return new ValuesCollectionAccessor<TKey, TValue>(this); }
}
#endregion
#region IDictionary Methods
/// <summary>
/// Adds an element with the provided key and value to the <see cref="IDictionary"/> object.
/// </summary>
/// <param name="key">The <see cref="object"/> to use as the key of the element to add.</param>
/// <param name="value">The <see cref="object"/> to use as the value of the element to add.</param>
void IDictionary.Add(object key, object? value)
{
throw new NotSupportedException();
}
/// <summary>
/// Determines whether the <see cref="IDictionary"/> object contains an element with the specified key.
/// </summary>
/// <param name="key">The key to locate in the <see cref="IDictionary"/> object.</param>
/// <returns>
/// true if the <see cref="IDictionary"/> contains an element with the key; otherwise, false.
/// </returns>
bool IDictionary.Contains(object key)
{
return this.ContainsKey((TKey)key);
}
/// <summary>
/// Returns an <see cref="IDictionaryEnumerator"/> object for the <see cref="IDictionary"/> object.
/// </summary>
/// <returns>
/// An <see cref="IDictionaryEnumerator"/> object for the <see cref="IDictionary"/> object.
/// </returns>
IDictionaryEnumerator IDictionary.GetEnumerator()
{
return new DictionaryEnumerator<TKey, TValue>(this.GetEnumerator());
}
/// <summary>
/// Removes the element with the specified key from the <see cref="IDictionary"/> object.
/// </summary>
/// <param name="key">The key of the element to remove.</param>
void IDictionary.Remove(object key)
{
throw new NotSupportedException();
}
/// <summary>
/// Gets or sets the element with the specified key.
/// </summary>
/// <param name="key">The key.</param>
/// <returns></returns>
object? IDictionary.this[object key]
{
get { return this[(TKey)key]; }
set { throw new NotSupportedException(); }
}
/// <summary>
/// Clears this instance.
/// </summary>
/// <exception cref="System.NotSupportedException"></exception>
void IDictionary.Clear()
{
throw new NotSupportedException();
}
#endregion
#region ICollection Methods
/// <summary>
/// Copies the elements of the <see cref="ICollection"/> to an <see cref="Array"/>, starting at a particular <see cref="Array"/> index.
/// </summary>
/// <param name="array">The one-dimensional <see cref="Array"/> that is the destination of the elements copied from <see cref="ICollection"/>. The <see cref="Array"/> must have zero-based indexing.</param>
/// <param name="index">The zero-based index in <paramref name="array"/> at which copying begins.</param>
void ICollection.CopyTo(Array array, int index)
{
_root.CopyTo(array, index, this.Count);
}
#endregion
#region ICollection Properties
/// <summary>
/// Gets an object that can be used to synchronize access to the <see cref="ICollection"/>.
/// </summary>
/// <returns>An object that can be used to synchronize access to the <see cref="ICollection"/>.</returns>
[DebuggerBrowsable(DebuggerBrowsableState.Never)]
object ICollection.SyncRoot
{
get { return this; }
}
/// <summary>
/// Gets a value indicating whether access to the <see cref="ICollection"/> is synchronized (thread safe).
/// </summary>
/// <returns>true if access to the <see cref="ICollection"/> is synchronized (thread safe); otherwise, false.</returns>
[DebuggerBrowsable(DebuggerBrowsableState.Never)]
bool ICollection.IsSynchronized
{
get
{
// This is immutable, so it is always thread-safe.
return true;
}
}
#endregion
#region IEnumerable<KeyValuePair<TKey, TValue>> Members
/// <summary>
/// Returns an enumerator that iterates through the collection.
/// </summary>
/// <returns>
/// A <see cref="IEnumerator{T}"/> that can be used to iterate through the collection.
/// </returns>
IEnumerator<KeyValuePair<TKey, TValue>> IEnumerable<KeyValuePair<TKey, TValue>>.GetEnumerator()
{
return this.IsEmpty ?
Enumerable.Empty<KeyValuePair<TKey, TValue>>().GetEnumerator() :
this.GetEnumerator();
}
#endregion
#region IEnumerable Members
/// <summary>
/// Returns an enumerator that iterates through a collection.
/// </summary>
/// <returns>
/// An <see cref="IEnumerator"/> object that can be used to iterate through the collection.
/// </returns>
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return this.GetEnumerator();
}
#endregion
/// <summary>
/// Returns an enumerator that iterates through the collection.
/// </summary>
/// <returns>
/// A <see cref="IEnumerator{T}"/> that can be used to iterate through the collection.
/// </returns>
public Enumerator GetEnumerator()
{
return _root.GetEnumerator();
}
/// <summary>
/// Creates a new sorted set wrapper for a node tree.
/// </summary>
/// <param name="root">The root of the collection.</param>
/// <param name="count">The number of elements in the map.</param>
/// <param name="keyComparer">The key comparer to use for the map.</param>
/// <param name="valueComparer">The value comparer to use for the map.</param>
/// <returns>The immutable sorted set instance.</returns>
private static ImmutableSortedDictionary<TKey, TValue> Wrap(Node root, int count, IComparer<TKey> keyComparer, IEqualityComparer<TValue> valueComparer)
{
return root.IsEmpty
? Empty.WithComparers(keyComparer, valueComparer)
: new ImmutableSortedDictionary<TKey, TValue>(root, count, keyComparer, valueComparer);
}
/// <summary>
/// Attempts to discover an <see cref="ImmutableSortedDictionary{TKey, TValue}"/> instance beneath some enumerable sequence
/// if one exists.
/// </summary>
/// <param name="sequence">The sequence that may have come from an immutable map.</param>
/// <param name="other">Receives the concrete <see cref="ImmutableSortedDictionary{TKey, TValue}"/> typed value if one can be found.</param>
/// <returns><c>true</c> if the cast was successful; <c>false</c> otherwise.</returns>
private static bool TryCastToImmutableMap(IEnumerable<KeyValuePair<TKey, TValue>> sequence, [NotNullWhen(true)] out ImmutableSortedDictionary<TKey, TValue>? other)
{
other = sequence as ImmutableSortedDictionary<TKey, TValue>;
if (other != null)
{
return true;
}
if (sequence is Builder builder)
{
other = builder.ToImmutable();
return true;
}
return false;
}
/// <summary>
/// Bulk adds entries to the map.
/// </summary>
/// <param name="items">The entries to add.</param>
/// <param name="overwriteOnCollision"><c>true</c> to allow the <paramref name="items"/> sequence to include duplicate keys and let the last one win; <c>false</c> to throw on collisions.</param>
/// <param name="avoidToSortedMap"><c>true</c> when being called from <see cref="WithComparers(IComparer{TKey}, IEqualityComparer{TValue})"/> to avoid a stack overflow.</param>
private ImmutableSortedDictionary<TKey, TValue> AddRange(IEnumerable<KeyValuePair<TKey, TValue>> items, bool overwriteOnCollision, bool avoidToSortedMap)
{
Requires.NotNull(items, nameof(items));
// Some optimizations may apply if we're an empty set.
if (this.IsEmpty && !avoidToSortedMap)
{
return this.FillFromEmpty(items, overwriteOnCollision);
}
// Let's not implement in terms of ImmutableSortedMap.Add so that we're
// not unnecessarily generating a new wrapping map object for each item.
ImmutableSortedDictionary<TKey, TValue>.Node result = _root;
int count = _count;
foreach (KeyValuePair<TKey, TValue> item in items)
{
bool mutated;
bool replacedExistingValue = false;
ImmutableSortedDictionary<TKey, TValue>.Node newResult = overwriteOnCollision
? result.SetItem(item.Key, item.Value, _keyComparer, _valueComparer, out replacedExistingValue, out mutated)
: result.Add(item.Key, item.Value, _keyComparer, _valueComparer, out mutated);
if (mutated)
{
result = newResult;
if (!replacedExistingValue)
{
count++;
}
}
}
return this.Wrap(result, count);
}
/// <summary>
/// Creates a wrapping collection type around a root node.
/// </summary>
/// <param name="root">The root node to wrap.</param>
/// <param name="adjustedCountIfDifferentRoot">The number of elements in the new tree, assuming it's different from the current tree.</param>
/// <returns>A wrapping collection type for the new tree.</returns>
private ImmutableSortedDictionary<TKey, TValue> Wrap(Node root, int adjustedCountIfDifferentRoot)
{
if (_root != root)
{
return root.IsEmpty ? this.Clear() : new ImmutableSortedDictionary<TKey, TValue>(root, adjustedCountIfDifferentRoot, _keyComparer, _valueComparer);
}
else
{
return this;
}
}
/// <summary>
/// Efficiently creates a new collection based on the contents of some sequence.
/// </summary>
private ImmutableSortedDictionary<TKey, TValue> FillFromEmpty(IEnumerable<KeyValuePair<TKey, TValue>> items, bool overwriteOnCollision)
{
Debug.Assert(this.IsEmpty);
Requires.NotNull(items, nameof(items));
// If the items being added actually come from an ImmutableSortedSet<T>,
// and the sort order is equivalent, then there is no value in reconstructing it.
ImmutableSortedDictionary<TKey, TValue>? other;
if (TryCastToImmutableMap(items, out other))
{
return other.WithComparers(this.KeyComparer, this.ValueComparer);
}
SortedDictionary<TKey, TValue> dictionary;
if (items is IDictionary<TKey, TValue> itemsAsDictionary)
{
dictionary = new SortedDictionary<TKey, TValue>(itemsAsDictionary, this.KeyComparer);
}
else
{
dictionary = new SortedDictionary<TKey, TValue>(this.KeyComparer);
foreach (KeyValuePair<TKey, TValue> item in items)
{
if (overwriteOnCollision)
{
dictionary[item.Key] = item.Value;
}
else
{
TValue value;
if (dictionary.TryGetValue(item.Key, out value!))
{
if (!_valueComparer.Equals(value, item.Value))
{
throw new ArgumentException(SR.Format(SR.DuplicateKey, item.Key));
}
}
else
{
dictionary.Add(item.Key, item.Value);
}
}
}
}
if (dictionary.Count == 0)
{
return this;
}
Node root = Node.NodeTreeFromSortedDictionary(dictionary);
return new ImmutableSortedDictionary<TKey, TValue>(root, dictionary.Count, this.KeyComparer, this.ValueComparer);
}
}
}
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