【.NET / C#】SubarrayUtils（查找子数组工具类）
C# 查找子数组工具类
/// <summary>/// Code shared to do searches/// </summary>public class SubarrayUtils{ /// <summary> /// Code shared by ArraySegment to do searches. /// The source is the ArraySegment being searched, and the target is the ArraySegment being searched for. /// </summary> /// <typeparam name="T"></typeparam> /// <param name="source">the ArraySegment being searched</param> /// <param name="target">the ArraySegment being searched for</param> /// <returns></returns> public static int IndexOf<T>(ArraySegment<T> source, ArraySegment<T> target) where T : struct { return IndexOf(source.Array, source.Offset, source.Count, target.Array, target.Offset, target.Count); } /// <summary> /// Code shared by array to do searches. /// The source is the array being searched, and the target is the array being searched for. /// </summary> /// <typeparam name="T"></typeparam> /// <param name="source">the array being searched</param> /// <param name="sourceOffset">offset of the source array</param> /// <param name="sourceCount">count of the source array</param> /// <param name="target">the array being searched for</param> /// <param name="targetOffset">offset of the target array</param> /// <param name="targetCount">count of the target array</param> /// <returns></returns> public static int IndexOf<T>( T[] source, int sourceOffset, int sourceCount, T[] target, int targetOffset, int targetCount) where T : struct { return IndexOf(source, sourceOffset, sourceCount, target, targetOffset, targetCount, 0); } /// <summary> /// Code shared by array to do searches. /// The source is the array being searched, and the target is the array being searched for. /// </summary> /// <typeparam name="T"></typeparam> /// <param name="source">the array being searched</param> /// <param name="sourceOffset">offset of the source array</param> /// <param name="sourceCount">count of the source array</param> /// <param name="target">the array being searched for</param> /// <param name="targetOffset">offset of the target array</param> /// <param name="targetCount">count of the target array</param> /// <param name="fromIndex">the index to begin searching from</param> /// <returns></returns> internal static int IndexOf<T>( T[] source, int sourceOffset, int sourceCount, T[] target, int targetOffset, int targetCount, int fromIndex) where T : struct { if (fromIndex >= sourceCount) { return (targetCount == 0 ? sourceCount : -1); } if (fromIndex < 0) { fromIndex = 0; } if (targetCount == 0) { return fromIndex; } T first = target[targetOffset]; int max = sourceOffset + (sourceCount - targetCount); for (int i = sourceOffset + fromIndex; i <= max; i++) { if (!Equals(source[i], first)) { while (++i <= max && !Equals(source[i], first)) ; } if (i <= max) { int j = i + 1; int end = j + targetCount - 1; for (int k = targetOffset + 1; j < end && Equals(source[j], target[k]); j++, k++) ; if (j == end) { return i - sourceOffset; } } } return -1; } /// <summary> /// Code shared by ArraySegment to do searches. /// The source is the ArraySegment being searched, and the target is the ArraySegment being searched for. /// </summary> /// <typeparam name="T"></typeparam> /// <param name="source">the ArraySegment being searched</param> /// <param name="target">the ArraySegment being searched for</param> /// <returns></returns> public static int LastIndexOf<T>(ArraySegment<T> source, ArraySegment<T> target) where T : struct { return LastIndexOf(source.Array, source.Offset, source.Count, target.Array, target.Offset, target.Count); } /// <summary> /// Code shared by array to do searches. /// The source is the array being searched, and the target is the array being searched for. /// </summary> /// <typeparam name="T"></typeparam> /// <param name="source">the array being searched</param> /// <param name="sourceOffset">offset of the source array</param> /// <param name="sourceCount">count of the source array</param> /// <param name="target">the array being searched for</param> /// <param name="targetOffset">offset of the target array</param> /// <param name="targetCount">count of the target array</param> /// <returns></returns> public static int LastIndexOf<T>( T[] source, int sourceOffset, int sourceCount, T[] target, int targetOffset, int targetCount) where T : struct { return LastIndexOf(source, sourceOffset, sourceCount, target, targetOffset, targetCount, sourceOffset + sourceCount); } /// <summary> /// Code shared by array to do searches. /// The source is the array being searched, and the target is the array being searched for. /// </summary> /// <typeparam name="T"></typeparam> /// <param name="source">the array being searched</param> /// <param name="sourceOffset">offset of the source array</param> /// <param name="sourceCount">count of the source array</param> /// <param name="target">the array being searched for</param> /// <param name="targetOffset">offset of the target array</param> /// <param name="targetCount">count of the target array</param> /// <param name="fromIndex">the index to begin searching from</param> /// <returns></returns> internal static int LastIndexOf<T>( T[] source, int sourceOffset, int sourceCount, T[] target, int targetOffset, int targetCount, int fromIndex) where T : struct { int rightIndex = sourceCount - targetCount; if (fromIndex < 0) { return -1; } if (fromIndex > rightIndex) { fromIndex = rightIndex; } if (targetCount == 0) { return fromIndex; } int arrLastIndex = targetOffset + targetCount - 1; T arrLastItem = target[arrLastIndex]; int min = sourceOffset + targetCount - 1; int i = min + fromIndex; startSearchForLastItem: while (true) { while (i >= min && !Equals(source[i], arrLastItem)) { i--; } if (i < min) { return -1; } int j = i - 1; int start = j - (targetCount - 1); int k = arrLastIndex - 1; while (j > start) { if (!Equals(source[j--], target[k--])) { i--; goto startSearchForLastItem; } } return start - sourceOffset + 1; } }} 赞 (0)