参考 http://www.cnblogs.com/brookshi/p/5353021.html
defaultCapacity意思是new List<T>时默认大小是4。
_items就是存List<T>元素的数组了，List<T>也是基于数组实现的。
分配原size的 2倍（ newSize = oldSize*2）
https://github.com/dotnet
https://github.com/dotnet/corefx/tree/master/src
https://github.com/dotnet/corefx/tree/master/src/System.Collections/src/System/Collections/Generic
Tips :以后找源码可以看这 ⇒ https://referencesource.microsoft.com/
github 找不到List.cs此文件（我找不到而已）,所以去microsoft 官网找的此文件，如下
https://referencesource.microsoft.com/#mscorlib/system/collections/generic/list.cs
简单看这，就行
static readonly T[] _emptyArray = new T[0];
// Constructs a List. The list is initially empty and has a capacity
// of zero. Upon adding the first element to the list the capacity is
// increased to 16, and then increased in multiples of two as required.
public List() {
_items = _emptyArray;
}
// Constructs a List with a given initial capacity. The list is
// initially empty, but will have room for the given number of elements
// before any reallocations are required.
//
public List(int capacity) {
if (capacity < 0) ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.capacity, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
Contract.EndContractBlock();
if (capacity == 0)
_items = _emptyArray;
else
_items = new T[capacity];
}
// Adds the given object to the end of this list. The size of the list is
// increased by one. If required, the capacity of the list is doubled
// before adding the new element.
//
public void Add(T item) {
if (_size == _items.Length) EnsureCapacity(_size + 1);
_items[_size++] = item;
_version++;
}
// Ensures that the capacity of this list is at least the given minimum
// value. If the currect capacity of the list is less than min, the
// capacity is increased to twice the current capacity or to min,
// whichever is larger.
private void EnsureCapacity(int min) {
if (_items.Length < min) {
int newCapacity = _items.Length == 0? _defaultCapacity : _items.Length * 2;
// Allow the list to grow to maximum possible capacity (~2G elements) before encountering overflow.
// Note that this check works even when _items.Length overflowed thanks to the (uint) cast
if ((uint)newCapacity > Array.MaxArrayLength) newCapacity = Array.MaxArrayLength;
if (newCapacity < min) newCapacity = min;
Capacity = newCapacity;
}
}
// Inserts the elements of the given collection at a given index. If
// required, the capacity of the list is increased to twice the previous
// capacity or the new size, whichever is larger. Ranges may be added
// to the end of the list by setting index to the List's size.
//
public void InsertRange(int index, IEnumerable<T> collection) {
if (collection==null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.collection);
}
if ((uint)index > (uint)_size) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_Index);
}
Contract.EndContractBlock();
ICollection<T> c = collection as ICollection<T>;
if( c != null ) { // if collection is ICollection<T>
int count = c.Count;
if (count > 0) {
EnsureCapacity(_size + count);
if (index < _size) {
Array.Copy(_items, index, _items, index + count, _size - index);
}
// If we're inserting a List into itself, we want to be able to deal with that.
if (this == c) {
// Copy first part of _items to insert location
Array.Copy(_items, 0, _items, index, index);
// Copy last part of _items back to inserted location
Array.Copy(_items, index+count, _items, index*2, _size-index);
}
else {
T[] itemsToInsert = new T[count];
c.CopyTo(itemsToInsert, 0);
itemsToInsert.CopyTo(_items, index);
}
_size += count;
}
}
else {
using(IEnumerator<T> en = collection.GetEnumerator()) {
while(en.MoveNext()) {
Insert(index++, en.Current);
}
}
}
_version++;
}
// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
/*============================================================
**
** Class: List
**
** <OWNER>Microsoft</OWNER>
**
** Purpose: Implements a generic, dynamically sized list as an
** array.
**
**
===========================================================*/
namespace System.Collections.Generic {
using System;
using System.Runtime;
using System.Runtime.Versioning;
using System.Diagnostics;
using System.Diagnostics.Contracts;
using System.Collections.ObjectModel;
using System.Security.Permissions;
// Implements a variable-size List that uses an array of objects to store the
// elements. A List has a capacity, which is the allocated length
// of the internal array. As elements are added to a List, the capacity
// of the List is automatically increased as required by reallocating the
// internal array.
//
[DebuggerTypeProxy(typeof(Mscorlib_CollectionDebugView<>))]
[DebuggerDisplay("Count = {Count}")]
[Serializable]
public class List<T> : IList<T>, System.Collections.IList, IReadOnlyList<T>
{
private const int _defaultCapacity = 4;
private T[] _items;
[ContractPublicPropertyName("Count")]
private int _size;
private int _version;
[NonSerialized]
private Object _syncRoot;
static readonly T[] _emptyArray = new T[0];
// Constructs a List. The list is initially empty and has a capacity
// of zero. Upon adding the first element to the list the capacity is
// increased to 16, and then increased in multiples of two as required.
public List() {
_items = _emptyArray;
}
// Constructs a List with a given initial capacity. The list is
// initially empty, but will have room for the given number of elements
// before any reallocations are required.
//
public List(int capacity) {
if (capacity < 0) ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.capacity, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
Contract.EndContractBlock();
if (capacity == 0)
_items = _emptyArray;
else
_items = new T[capacity];
}
// Constructs a List, copying the contents of the given collection. The
// size and capacity of the new list will both be equal to the size of the
// given collection.
//
public List(IEnumerable<T> collection) {
if (collection==null)
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.collection);
Contract.EndContractBlock();
ICollection<T> c = collection as ICollection<T>;
if( c != null) {
int count = c.Count;
if (count == 0)
{
_items = _emptyArray;
}
else {
_items = new T[count];
c.CopyTo(_items, 0);
_size = count;
}
}
else {
_size = 0;
_items = _emptyArray;
// This enumerable could be empty. Let Add allocate a new array, if needed.
// Note it will also go to _defaultCapacity first, not 1, then 2, etc.
using(IEnumerator<T> en = collection.GetEnumerator()) {
while(en.MoveNext()) {
Add(en.Current);
}
}
}
}
// Gets and sets the capacity of this list. The capacity is the size of
// the internal array used to hold items. When set, the internal
// array of the list is reallocated to the given capacity.
//
public int Capacity {
get {
Contract.Ensures(Contract.Result<int>() >= 0);
return _items.Length;
}
set {
if (value < _size) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.value, ExceptionResource.ArgumentOutOfRange_SmallCapacity);
}
Contract.EndContractBlock();
if (value != _items.Length) {
if (value > 0) {
T[] newItems = new T[value];
if (_size > 0) {
Array.Copy(_items, 0, newItems, 0, _size);
}
_items = newItems;
}
else {
_items = _emptyArray;
}
}
}
}
// Read-only property describing how many elements are in the List.
public int Count {
get {
Contract.Ensures(Contract.Result<int>() >= 0);
return _size;
}
}
bool System.Collections.IList.IsFixedSize {
get { return false; }
}
// Is this List read-only?
bool ICollection<T>.IsReadOnly {
get { return false; }
}
bool System.Collections.IList.IsReadOnly {
get { return false; }
}
// Is this List synchronized (thread-safe)?
bool System.Collections.ICollection.IsSynchronized {
get { return false; }
}
// Synchronization root for this object.
Object System.Collections.ICollection.SyncRoot {
get {
if( _syncRoot == null) {
System.Threading.Interlocked.CompareExchange<Object>(ref _syncRoot, new Object(), null);
}
return _syncRoot;
}
}
// Sets or Gets the element at the given index.
//
public T this[int index] {
get {
// Following trick can reduce the range check by one
if ((uint) index >= (uint)_size) {
ThrowHelper.ThrowArgumentOutOfRangeException();
}
Contract.EndContractBlock();
return _items[index];
}
set {
if ((uint) index >= (uint)_size) {
ThrowHelper.ThrowArgumentOutOfRangeException();
}
Contract.EndContractBlock();
_items[index] = value;
_version++;
}
}
private static bool IsCompatibleObject(object value) {
// Non-null values are fine. Only accept nulls if T is a class or Nullable<U>.
// Note that default(T) is not equal to null for value types except when T is Nullable<U>.
return ((value is T) || (value == null && default(T) == null));
}
Object System.Collections.IList.this[int index] {
get {
return this[index];
}
set {
ThrowHelper.IfNullAndNullsAreIllegalThenThrow<T>(value, ExceptionArgument.value);
try {
this[index] = (T)value;
}
catch (InvalidCastException) {
ThrowHelper.ThrowWrongValueTypeArgumentException(value, typeof(T));
}
}
}
// Adds the given object to the end of this list. The size of the list is
// increased by one. If required, the capacity of the list is doubled
// before adding the new element.
//
public void Add(T item) {
if (_size == _items.Length) EnsureCapacity(_size + 1);
_items[_size++] = item;
_version++;
}
int System.Collections.IList.Add(Object item)
{
ThrowHelper.IfNullAndNullsAreIllegalThenThrow<T>(item, ExceptionArgument.item);
try {
Add((T) item);
}
catch (InvalidCastException) {
ThrowHelper.ThrowWrongValueTypeArgumentException(item, typeof(T));
}
return Count - 1;
}
// Adds the elements of the given collection to the end of this list. If
// required, the capacity of the list is increased to twice the previous
// capacity or the new size, whichever is larger.
//
public void AddRange(IEnumerable<T> collection) {
Contract.Ensures(Count >= Contract.OldValue(Count));
InsertRange(_size, collection);
}
public ReadOnlyCollection<T> AsReadOnly() {
Contract.Ensures(Contract.Result<ReadOnlyCollection<T>>() != null);
return new ReadOnlyCollection<T>(this);
}
// Searches a section of the list for a given element using a binary search
// algorithm. Elements of the list are compared to the search value using
// the given IComparer interface. If comparer is null, elements of
// the list are compared to the search value using the IComparable
// interface, which in that case must be implemented by all elements of the
// list and the given search value. This method assumes that the given
// section of the list is already sorted; if this is not the case, the
// result will be incorrect.
//
// The method returns the index of the given value in the list. If the
// list does not contain the given value, the method returns a negative
// integer. The bitwise complement operator (~) can be applied to a
// negative result to produce the index of the first element (if any) that
// is larger than the given search value. This is also the index at which
// the search value should be inserted into the list in order for the list
// to remain sorted.
//
// The method uses the Array.BinarySearch method to perform the
// search.
//
public int BinarySearch(int index, int count, T item, IComparer<T> comparer) {
if (index < 0)
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
if (count < 0)
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
if (_size - index < count)
ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidOffLen);
Contract.Ensures(Contract.Result<int>() <= index + count);
Contract.EndContractBlock();
return Array.BinarySearch<T>(_items, index, count, item, comparer);
}
public int BinarySearch(T item)
{
Contract.Ensures(Contract.Result<int>() <= Count);
return BinarySearch(0, Count, item, null);
}
public int BinarySearch(T item, IComparer<T> comparer)
{
Contract.Ensures(Contract.Result<int>() <= Count);
return BinarySearch(0, Count, item, comparer);
}
// Clears the contents of List.
public void Clear() {
if (_size > 0)
{
Array.Clear(_items, 0, _size); // Don't need to doc this but we clear the elements so that the gc can reclaim the references.
_size = 0;
}
_version++;
}
// Contains returns true if the specified element is in the List.
// It does a linear, O(n) search. Equality is determined by calling
// item.Equals().
//
public bool Contains(T item) {
if ((Object) item == null) {
for(int i=0; i<_size; i++)
if ((Object) _items[i] == null)
return true;
return false;
}
else {
EqualityComparer<T> c = EqualityComparer<T>.Default;
for(int i=0; i<_size; i++) {
if (c.Equals(_items[i], item)) return true;
}
return false;
}
}
bool System.Collections.IList.Contains(Object item)
{
if(IsCompatibleObject(item)) {
return Contains((T) item);
}
return false;
}
public List<TOutput> ConvertAll<TOutput>(Converter<T,TOutput> converter) {
if( converter == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.converter);
}
// @
Contract.EndContractBlock();
List<TOutput> list = new List<TOutput>(_size);
for( int i = 0; i< _size; i++) {
list._items[i] = converter(_items[i]);
}
list._size = _size;
return list;
}
// Copies this List into array, which must be of a
// compatible array type.
//
public void CopyTo(T[] array) {
CopyTo(array, 0);
}
// Copies this List into array, which must be of a
// compatible array type.
//
void System.Collections.ICollection.CopyTo(Array array, int arrayIndex) {
if ((array != null) && (array.Rank != 1)) {
ThrowHelper.ThrowArgumentException(ExceptionResource.Arg_RankMultiDimNotSupported);
}
Contract.EndContractBlock();
try {
// Array.Copy will check for NULL.
Array.Copy(_items, 0, array, arrayIndex, _size);
}
catch(ArrayTypeMismatchException){
ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidArrayType);
}
}
// Copies a section of this list to the given array at the given index.
//
// The method uses the Array.Copy method to copy the elements.
//
public void CopyTo(int index, T[] array, int arrayIndex, int count) {
if (_size - index < count) {
ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidOffLen);
}
Contract.EndContractBlock();
// Delegate rest of error checking to Array.Copy.
Array.Copy(_items, index, array, arrayIndex, count);
}
public void CopyTo(T[] array, int arrayIndex) {
// Delegate rest of error checking to Array.Copy.
Array.Copy(_items, 0, array, arrayIndex, _size);
}
// Ensures that the capacity of this list is at least the given minimum
// value. If the currect capacity of the list is less than min, the
// capacity is increased to twice the current capacity or to min,
// whichever is larger.
private void EnsureCapacity(int min) {
if (_items.Length < min) {
int newCapacity = _items.Length == 0? _defaultCapacity : _items.Length * 2;
// Allow the list to grow to maximum possible capacity (~2G elements) before encountering overflow.
// Note that this check works even when _items.Length overflowed thanks to the (uint) cast
if ((uint)newCapacity > Array.MaxArrayLength) newCapacity = Array.MaxArrayLength;
if (newCapacity < min) newCapacity = min;
Capacity = newCapacity;
}
}
public bool Exists(Predicate<T> match) {
return FindIndex(match) != -1;
}
public T Find(Predicate<T> match) {
if( match == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.EndContractBlock();
for(int i = 0 ; i < _size; i++) {
if(match(_items[i])) {
return _items[i];
}
}
return default(T);
}
public List<T> FindAll(Predicate<T> match) {
if( match == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.EndContractBlock();
List<T> list = new List<T>();
for(int i = 0 ; i < _size; i++) {
if(match(_items[i])) {
list.Add(_items[i]);
}
}
return list;
}
public int FindIndex(Predicate<T> match) {
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() < Count);
return FindIndex(0, _size, match);
}
public int FindIndex(int startIndex, Predicate<T> match) {
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() < startIndex + Count);
return FindIndex(startIndex, _size - startIndex, match);
}
public int FindIndex(int startIndex, int count, Predicate<T> match) {
if( (uint)startIndex > (uint)_size ) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.startIndex, ExceptionResource.ArgumentOutOfRange_Index);
}
if (count < 0 || startIndex > _size - count) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_Count);
}
if( match == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() < startIndex + count);
Contract.EndContractBlock();
int endIndex = startIndex + count;
for( int i = startIndex; i < endIndex; i++) {
if( match(_items[i])) return i;
}
return -1;
}
public T FindLast(Predicate<T> match) {
if( match == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.EndContractBlock();
for(int i = _size - 1 ; i >= 0; i--) {
if(match(_items[i])) {
return _items[i];
}
}
return default(T);
}
public int FindLastIndex(Predicate<T> match) {
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() < Count);
return FindLastIndex(_size - 1, _size, match);
}
public int FindLastIndex(int startIndex, Predicate<T> match) {
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() <= startIndex);
return FindLastIndex(startIndex, startIndex + 1, match);
}
public int FindLastIndex(int startIndex, int count, Predicate<T> match) {
if( match == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() <= startIndex);
Contract.EndContractBlock();
if(_size == 0) {
// Special case for 0 length List
if( startIndex != -1) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.startIndex, ExceptionResource.ArgumentOutOfRange_Index);
}
}
else {
// Make sure we're not out of range
if ( (uint)startIndex >= (uint)_size) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.startIndex, ExceptionResource.ArgumentOutOfRange_Index);
}
}
// 2nd have of this also catches when startIndex == MAXINT, so MAXINT - 0 + 1 == -1, which is < 0.
if (count < 0 || startIndex - count + 1 < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_Count);
}
int endIndex = startIndex - count;
for( int i = startIndex; i > endIndex; i--) {
if( match(_items[i])) {
return i;
}
}
return -1;
}
public void ForEach(Action<T> action) {
if( action == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.EndContractBlock();
int version = _version;
for(int i = 0 ; i < _size; i++) {
if (version != _version && BinaryCompatibility.TargetsAtLeast_Desktop_V4_5) {
break;
}
action(_items[i]);
}
if (version != _version && BinaryCompatibility.TargetsAtLeast_Desktop_V4_5)
ThrowHelper.ThrowInvalidOperationException(ExceptionResource.InvalidOperation_EnumFailedVersion);
}
// Returns an enumerator for this list with the given
// permission for removal of elements. If modifications made to the list
// while an enumeration is in progress, the MoveNext and
// GetObject methods of the enumerator will throw an exception.
//
public Enumerator GetEnumerator() {
return new Enumerator(this);
}
/// <internalonly/>
IEnumerator<T> IEnumerable<T>.GetEnumerator() {
return new Enumerator(this);
}
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() {
return new Enumerator(this);
}
public List<T> GetRange(int index, int count) {
if (index < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if (count < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if (_size - index < count) {
ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidOffLen);
}
Contract.Ensures(Contract.Result<List<T>>() != null);
Contract.EndContractBlock();
List<T> list = new List<T>(count);
Array.Copy(_items, index, list._items, 0, count);
list._size = count;
return list;
}
// Returns the index of the first occurrence of a given value in a range of
// this list. The list is searched forwards from beginning to end.
// The elements of the list are compared to the given value using the
// Object.Equals method.
//
// This method uses the Array.IndexOf method to perform the
// search.
//
public int IndexOf(T item) {
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() < Count);
return Array.IndexOf(_items, item, 0, _size);
}
int System.Collections.IList.IndexOf(Object item)
{
if(IsCompatibleObject(item)) {
return IndexOf((T)item);
}
return -1;
}
// Returns the index of the first occurrence of a given value in a range of
// this list. The list is searched forwards, starting at index
// index and ending at count number of elements. The
// elements of the list are compared to the given value using the
// Object.Equals method.
//
// This method uses the Array.IndexOf method to perform the
// search.
//
public int IndexOf(T item, int index) {
if (index > _size)
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_Index);
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() < Count);
Contract.EndContractBlock();
return Array.IndexOf(_items, item, index, _size - index);
}
// Returns the index of the first occurrence of a given value in a range of
// this list. The list is searched forwards, starting at index
// index and upto count number of elements. The
// elements of the list are compared to the given value using the
// Object.Equals method.
//
// This method uses the Array.IndexOf method to perform the
// search.
//
public int IndexOf(T item, int index, int count) {
if (index > _size)
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_Index);
if (count <0 || index > _size - count) ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_Count);
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() < Count);
Contract.EndContractBlock();
return Array.IndexOf(_items, item, index, count);
}
// Inserts an element into this list at a given index. The size of the list
// is increased by one. If required, the capacity of the list is doubled
// before inserting the new element.
//
public void Insert(int index, T item) {
// Note that insertions at the end are legal.
if ((uint) index > (uint)_size) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_ListInsert);
}
Contract.EndContractBlock();
if (_size == _items.Length) EnsureCapacity(_size + 1);
if (index < _size) {
Array.Copy(_items, index, _items, index + 1, _size - index);
}
_items[index] = item;
_size++;
_version++;
}
void System.Collections.IList.Insert(int index, Object item)
{
ThrowHelper.IfNullAndNullsAreIllegalThenThrow<T>(item, ExceptionArgument.item);
try {
Insert(index, (T) item);
}
catch (InvalidCastException) {
ThrowHelper.ThrowWrongValueTypeArgumentException(item, typeof(T));
}
}
// Inserts the elements of the given collection at a given index. If
// required, the capacity of the list is increased to twice the previous
// capacity or the new size, whichever is larger. Ranges may be added
// to the end of the list by setting index to the List's size.
//
public void InsertRange(int index, IEnumerable<T> collection) {
if (collection==null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.collection);
}
if ((uint)index > (uint)_size) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_Index);
}
Contract.EndContractBlock();
ICollection<T> c = collection as ICollection<T>;
if( c != null ) { // if collection is ICollection<T>
int count = c.Count;
if (count > 0) {
EnsureCapacity(_size + count);
if (index < _size) {
Array.Copy(_items, index, _items, index + count, _size - index);
}
// If we're inserting a List into itself, we want to be able to deal with that.
if (this == c) {
// Copy first part of _items to insert location
Array.Copy(_items, 0, _items, index, index);
// Copy last part of _items back to inserted location
Array.Copy(_items, index+count, _items, index*2, _size-index);
}
else {
T[] itemsToInsert = new T[count];
c.CopyTo(itemsToInsert, 0);
itemsToInsert.CopyTo(_items, index);
}
_size += count;
}
}
else {
using(IEnumerator<T> en = collection.GetEnumerator()) {
while(en.MoveNext()) {
Insert(index++, en.Current);
}
}
}
_version++;
}
// Returns the index of the last occurrence of a given value in a range of
// this list. The list is searched backwards, starting at the end
// and ending at the first element in the list. The elements of the list
// are compared to the given value using the Object.Equals method.
//
// This method uses the Array.LastIndexOf method to perform the
// search.
//
public int LastIndexOf(T item)
{
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(Contract.Result<int>() < Count);
if (_size == 0) { // Special case for empty list
return -1;
}
else {
return LastIndexOf(item, _size - 1, _size);
}
}
// Returns the index of the last occurrence of a given value in a range of
// this list. The list is searched backwards, starting at index
// index and ending at the first element in the list. The
// elements of the list are compared to the given value using the
// Object.Equals method.
//
// This method uses the Array.LastIndexOf method to perform the
// search.
//
public int LastIndexOf(T item, int index)
{
if (index >= _size)
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_Index);
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(((Count == 0) && (Contract.Result<int>() == -1)) || ((Count > 0) && (Contract.Result<int>() <= index)));
Contract.EndContractBlock();
return LastIndexOf(item, index, index + 1);
}
// Returns the index of the last occurrence of a given value in a range of
// this list. The list is searched backwards, starting at index
// index and upto count elements. The elements of
// the list are compared to the given value using the Object.Equals
// method.
//
// This method uses the Array.LastIndexOf method to perform the
// search.
//
public int LastIndexOf(T item, int index, int count) {
if ((Count != 0) && (index < 0)) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if ((Count !=0) && (count < 0)) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
Contract.Ensures(Contract.Result<int>() >= -1);
Contract.Ensures(((Count == 0) && (Contract.Result<int>() == -1)) || ((Count > 0) && (Contract.Result<int>() <= index)));
Contract.EndContractBlock();
if (_size == 0) { // Special case for empty list
return -1;
}
if (index >= _size) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_BiggerThanCollection);
}
if (count > index + 1) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_BiggerThanCollection);
}
return Array.LastIndexOf(_items, item, index, count);
}
// Removes the element at the given index. The size of the list is
// decreased by one.
//
public bool Remove(T item) {
int index = IndexOf(item);
if (index >= 0) {
RemoveAt(index);
return true;
}
return false;
}
void System.Collections.IList.Remove(Object item)
{
if(IsCompatibleObject(item)) {
Remove((T) item);
}
}
// This method removes all items which matches the predicate.
// The complexity is O(n).
public int RemoveAll(Predicate<T> match) {
if( match == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.Ensures(Contract.Result<int>() >= 0);
Contract.Ensures(Contract.Result<int>() <= Contract.OldValue(Count));
Contract.EndContractBlock();
int freeIndex = 0; // the first free slot in items array
// Find the first item which needs to be removed.
while( freeIndex < _size && !match(_items[freeIndex])) freeIndex++;
if( freeIndex >= _size) return 0;
int current = freeIndex + 1;
while( current < _size) {
// Find the first item which needs to be kept.
while( current < _size && match(_items[current])) current++;
if( current < _size) {
// copy item to the free slot.
_items[freeIndex++] = _items[current++];
}
}
Array.Clear(_items, freeIndex, _size - freeIndex);
int result = _size - freeIndex;
_size = freeIndex;
_version++;
return result;
}
// Removes the element at the given index. The size of the list is
// decreased by one.
//
public void RemoveAt(int index) {
if ((uint)index >= (uint)_size) {
ThrowHelper.ThrowArgumentOutOfRangeException();
}
Contract.EndContractBlock();
_size--;
if (index < _size) {
Array.Copy(_items, index + 1, _items, index, _size - index);
}
_items[_size] = default(T);
_version++;
}
// Removes a range of elements from this list.
//
public void RemoveRange(int index, int count) {
if (index < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if (count < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if (_size - index < count)
ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidOffLen);
Contract.EndContractBlock();
if (count > 0) {
int i = _size;
_size -= count;
if (index < _size) {
Array.Copy(_items, index + count, _items, index, _size - index);
}
Array.Clear(_items, _size, count);
_version++;
}
}
// Reverses the elements in this list.
public void Reverse() {
Reverse(0, Count);
}
// Reverses the elements in a range of this list. Following a call to this
// method, an element in the range given by index and count
// which was previously located at index i will now be located at
// index index + (index + count - i - 1).
//
// This method uses the Array.Reverse method to reverse the
// elements.
//
public void Reverse(int index, int count) {
if (index < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if (count < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if (_size - index < count)
ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidOffLen);
Contract.EndContractBlock();
Array.Reverse(_items, index, count);
_version++;
}
// Sorts the elements in this list. Uses the default comparer and
// Array.Sort.
public void Sort()
{
Sort(0, Count, null);
}
// Sorts the elements in this list. Uses Array.Sort with the
// provided comparer.
public void Sort(IComparer<T> comparer)
{
Sort(0, Count, comparer);
}
// Sorts the elements in a section of this list. The sort compares the
// elements to each other using the given IComparer interface. If
// comparer is null, the elements are compared to each other using
// the IComparable interface, which in that case must be implemented by all
// elements of the list.
//
// This method uses the Array.Sort method to sort the elements.
//
public void Sort(int index, int count, IComparer<T> comparer) {
if (index < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if (count < 0) {
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if (_size - index < count)
ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidOffLen);
Contract.EndContractBlock();
Array.Sort<T>(_items, index, count, comparer);
_version++;
}
public void Sort(Comparison<T> comparison) {
if( comparison == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.EndContractBlock();
if( _size > 0) {
IComparer<T> comparer = new Array.FunctorComparer<T>(comparison);
Array.Sort(_items, 0, _size, comparer);
}
}
// ToArray returns a new Object array containing the contents of the List.
// This requires copying the List, which is an O(n) operation.
public T[] ToArray() {
Contract.Ensures(Contract.Result<T[]>() != null);
Contract.Ensures(Contract.Result<T[]>().Length == Count);
T[] array = new T[_size];
Array.Copy(_items, 0, array, 0, _size);
return array;
}
// Sets the capacity of this list to the size of the list. This method can
// be used to minimize a list's memory overhead once it is known that no
// new elements will be added to the list. To completely clear a list and
// release all memory referenced by the list, execute the following
// statements:
//
// list.Clear();
// list.TrimExcess();
//
public void TrimExcess() {
int threshold = (int)(((double)_items.Length) * 0.9);
if( _size < threshold ) {
Capacity = _size;
}
}
public bool TrueForAll(Predicate<T> match) {
if( match == null) {
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
}
Contract.EndContractBlock();
for(int i = 0 ; i < _size; i++) {
if( !match(_items[i])) {
return false;
}
}
return true;
}
internal static IList<T> Synchronized(List<T> list) {
return new SynchronizedList(list);
}
[Serializable()]
internal class SynchronizedList : IList<T> {
private List<T> _list;
private Object _root;
internal SynchronizedList(List<T> list) {
_list = list;
_root = ((System.Collections.ICollection)list).SyncRoot;
}
public int Count {
get {
lock (_root) {
return _list.Count;
}
}
}
public bool IsReadOnly {
get {
return ((ICollection<T>)_list).IsReadOnly;
}
}
public void Add(T item) {
lock (_root) {
_list.Add(item);
}
}
public void Clear() {
lock (_root) {
_list.Clear();
}
}
public bool Contains(T item) {
lock (_root) {
return _list.Contains(item);
}
}
public void CopyTo(T[] array, int arrayIndex) {
lock (_root) {
_list.CopyTo(array, arrayIndex);
}
}
public bool Remove(T item) {
lock (_root) {
return _list.Remove(item);
}
}
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() {
lock (_root) {
return _list.GetEnumerator();
}
}
IEnumerator<T> IEnumerable<T>.GetEnumerator() {
lock (_root) {
return ((IEnumerable<T>)_list).GetEnumerator();
}
}
public T this[int index] {
get {
lock(_root) {
return _list[index];
}
}
set {
lock(_root) {
_list[index] = value;
}
}
}
public int IndexOf(T item) {
lock (_root) {
return _list.IndexOf(item);
}
}
public void Insert(int index, T item) {
lock (_root) {
_list.Insert(index, item);
}
}
public void RemoveAt(int index) {
lock (_root) {
_list.RemoveAt(index);
}
}
}
[Serializable]
public struct Enumerator : IEnumerator<T>, System.Collections.IEnumerator
{
private List<T> list;
private int index;
private int version;
private T current;
internal Enumerator(List<T> list) {
this.list = list;
index = 0;
version = list._version;
current = default(T);
}
public void Dispose() {
}
public bool MoveNext() {
List<T> localList = list;
if (version == localList._version && ((uint)index < (uint)localList._size))
{
current = localList._items[index];
index++;
return true;
}
return MoveNextRare();
}
private bool MoveNextRare()
{
if (version != list._version) {
ThrowHelper.ThrowInvalidOperationException(ExceptionResource.InvalidOperation_EnumFailedVersion);
}
index = list._size + 1;
current = default(T);
return false;
}
public T Current {
get {
return current;
}
}
Object System.Collections.IEnumerator.Current {
get {
if( index == 0 || index == list._size + 1) {
ThrowHelper.ThrowInvalidOperationException(ExceptionResource.InvalidOperation_EnumOpCantHappen);
}
return Current;
}
}
void System.Collections.IEnumerator.Reset() {
if (version != list._version) {
ThrowHelper.ThrowInvalidOperationException(ExceptionResource.InvalidOperation_EnumFailedVersion);
}
index = 0;
current = default(T);
}
}
}
}