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using System; using System.Collections.Generic; using System.Text;
namespace Apewer {
/// <summary>数组构建器。</summary>
public sealed class ArrayBuilder<T> {
private Type _type = typeof(T);
private T[] _array; private int _capacity; private int _count; private int _step;
/// <summary>创建构建程序实例。</summary>
/// <param name="step">每次扩容的增量,最小值:1,默认值:256。</param>
/// <exception cref="ArgumentNullException"></exception>
public ArrayBuilder(int step = 256) { if (step < 1) throw new ArgumentOutOfRangeException(nameof(step)); _step = step; _capacity = step; _count = 0; _array = new T[step]; }
private ArrayBuilder(ArrayBuilder<T> old) { _step = old._step; _capacity = old._capacity; _count = old._count; _array = new T[_capacity]; if (_count > 0) Array.Copy(old._array, _array, _count); }
/// <summary>获取或设置指定位置的元素,索引器范围为 [0, Length)。</summary>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public T this[int index] { get { if (index < 0 || index >= _count) throw new ArgumentOutOfRangeException("索引超出了当前数组的范围。"); return _array[index]; } set { if (index < 0 || index >= _count) throw new ArgumentOutOfRangeException("索引超出了当前数组的范围。"); _array[index] = value; } }
/// <summary>源数组。</summary>
public T[] Origin { get => _array; }
/// <summary>缓冲区的容量。</summary>
public int Capacity { get => _capacity; }
/// <summary>当前的元素数量。</summary>
public int Length { get => _count; }
/// <summary>当前的元素数量。</summary>
public int Count { get => _count; }
/// <summary>指定元素在数组中的偏移位置。</summary>
public int IndexOf(T value) { var array = _array; var length = _count; if (length < 1) return -1; for (var i = 0; i < length; i++) { var item = array[i]; if (item == null) continue; if (item.Equals(value)) return i; } return -1; }
/// <summary>已包含指定的元素。</summary>
public bool Contains(T value) => IndexOf(value) > -1;
/// <summary>添加元素。</summary>
public void Add(T item) { if (_capacity - _count < 1) { _capacity += _step; var temp = new T[_capacity]; Array.Copy(_array, temp, _count); _array = temp; } _array[_count] = item; _count++; }
/// <summary>添加多个元素。</summary>
public void Add(params T[] items) { if (items == null) return;
var length = items.Length; if (length < 1) return;
if (_capacity - _count < length) { _capacity = _count + length; var temp = new T[_capacity]; Array.Copy(_array, temp, _count); _array = temp; }
Array.Copy(items, 0, _array, _count, length); _count += length; }
/// <summary>添加多个元素。</summary>
public void Add(ICollection<T> items) { if (items == null) return;
var length = items.Count; if (length < 1) return;
if (_capacity - _count < length) { _capacity = _count + length; var temp = new T[_capacity]; Array.Copy(_array, temp, _count); _array = temp; }
items.CopyTo(_array, _count); _count += length; }
/// <summary>添加多个元素。</summary>
public void Add(IEnumerable<T> items) { if (items == null) return; foreach (var item in items) Add(item); }
/// <summary>添加元素。</summary>
/// <param name="buffer">要添加的元素数组。</param>
/// <param name="offset">buffer 的开始位置。</param>
/// <param name="count">buffer 的元素数量。</param>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public void Add(T[] buffer, int offset, int count) { if (buffer == null) throw new ArgumentNullException(nameof(buffer)); var length = buffer.Length; if (offset < 0 || offset >= length || count < 0) throw new ArgumentOutOfRangeException(); if (offset + count > length) throw new ArgumentOutOfRangeException();
if (_capacity - _count < length) { _capacity = _count + length; var temp = new T[_capacity]; Array.Copy(_array, temp, _count); _array = temp; }
Array.Copy(buffer, offset, _array, _count, count); _count += count; }
/// <summary>清空所有元素。</summary>
public void Clear() { _capacity = 0; _count = 0; _array = new T[0]; }
// 修剪数组,去除剩余空间。
void Trim() { if (_count == 0) { if (_capacity > 0) { _capacity = 0; _array = new T[0]; } return; }
if (_count == _capacity) return;
var array = new T[_count]; Array.Copy(_array, array, _count); _capacity = _count; }
#region 模仿 JavaScript 数组方法。
/// <summary>添加元素。</summary>
public void Push(T item) => Add(item);
/// <summary>取出最后一个元素。</summary>
public T Pop(Func<T> @default = null) { if (_count > 0) { var offset = _count - 1; var value = _array[offset]; _array[offset] = default(T); _count -= 1; return value; } return @default == null ? default(T) : @default.Invoke(); }
/// <summary>取出第一个元素,当数组为空时使用指定方法返回默认值。</summary>
public T Shift(Func<T> @default = null) { if (_count > 0) { var value = _array[0]; var temp = new T[_count]; if (_count > 1) Array.Copy(_array, 1, temp, 0, _count - 1); _array = temp; _count -= 1; return value; } return @default == null ? default(T) : @default.Invoke(); }
/// <summary>添加元素到数组最前端。</summary>
public void Unshift(T item) { var remains = _capacity - _count; var length = remains > 0 ? _capacity : (_capacity + _step);
var temp = new T[length]; temp[0] = item; if (_count > 0) { Array.Copy(_array, 0, temp, 1, _count); _count++; } _capacity = length; _array = temp; }
#endregion
#region 导出、转换。
/// <summary>导出字符串。</summary>
public override string ToString() => ToString(null);
/// <summary>导出字符串。</summary>
/// <param name="separator">分隔符。</param>
public string ToString(string separator) { var sb = new StringBuilder(); var hasSeparator = !string.IsNullOrEmpty(separator); if (_type.IsValueType) { for (var i = 0; i < _count; i++) { if (i > 0 && hasSeparator) sb.Append(separator); sb.Append(_array[i].ToString()); } } else { var isString = _type == typeof(string); for (var i = 0; i < _count; i++) { if (_array[i] == null) continue; if (i > 0 && hasSeparator) sb.Append(separator); sb.Append(isString ? _array[i] as string : _array[i].ToString()); } } return sb.ToString(); }
/// <summary>导出到新数组。</summary>
/// <param name="clear">导出后清空元素。</param>
public T[] Export(bool clear = false) { if (_count == 0) return new T[0]; if (_count == _capacity) return _array; var array = new T[_count]; Array.Copy(_array, array, _count); if (clear) _array = new T[0]; return array; }
/// <summary>克隆当前实例,生成新实例。</summary>
public ArrayBuilder<T> Clone() => new ArrayBuilder<T>(this);
/// <summary>使用 Export 方法实现从 ArrayBuilder<T> 到 T[] 的隐式转换。</summary>
public static implicit operator T[](ArrayBuilder<T> instance) => instance == null ? null : instance.Export();
internal static string Text(ArrayBuilder<char> ab) { if (ab == null) return ""; if (ab._count < 1) return ""; return new string(ab._array, 0, ab._count); }
internal static string Text(ArrayBuilder<char> ab, int start, int count) { if (start < 0) throw new ArgumentOutOfRangeException("startIndex", "起始位置不可小于 0。"); if (count < 0) throw new ArgumentOutOfRangeException("maxCount", "最大数量不可小于 0。");
if (ab == null || count < 1) return ""; if (start < 0) start = 0; var total = ab._count; if (start + count > total) count = total - start; if (count < 1) return ""; return new string(ab._array, start, count); }
internal static string Join(ArrayBuilder<string> ab, string separator) { if (ab == null) return ""; return Join(ab, separator, 0, ab._count); }
internal static string Join(ArrayBuilder<string> ab, string separator, int start, int count) { if (start < 0) throw new ArgumentOutOfRangeException("startIndex", "起始位置不可小于 0。"); if (count < 0) throw new ArgumentOutOfRangeException("maxCount", "最大数量不可小于 0。");
if (ab == null || count < 1) return ""; // 数组为空。
if (start < 0) start = 0; // 修正起始位置最小值。
var total = ab._count; // 数组中的元素总数。
if (start + count > total) count = total - start; // 最大数量。
if (count < 1) return ""; // 不取任何元素。
var end = start + count; // 结束位置。
var se = string.IsNullOrEmpty(separator); // 分隔符为空。
var sb = new StringBuilder(); for (var i = start; i < end; i++) { var item = ab._array[i]; if (i > start && !se) sb.Append(separator); if (item == null || item == "") continue; sb.Append(item); } return sb.ToString(); }
#endregion
}
}
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