From ba7937390841c1e4859eec8c70d00b6e302fa955 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=99=88=E5=9B=BD=E4=BC=9F?= <366193849@qq.com>
Date: Fri, 14 Oct 2022 11:44:11 +0800
Subject: [PATCH] =?UTF-8?q?=E5=85=AC=E5=BC=80GetSpan=E6=96=B9=E6=B3=95?=
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---
 WindivertDotnet/WinDivertPacket.cs | 80 ++++++------------------------
 1 file changed, 15 insertions(+), 65 deletions(-)

diff --git a/WindivertDotnet/WinDivertPacket.cs b/WindivertDotnet/WinDivertPacket.cs
index cd9eee9..cf9d85c 100644
--- a/WindivertDotnet/WinDivertPacket.cs
+++ b/WindivertDotnet/WinDivertPacket.cs
@@ -1,6 +1,5 @@
 using Microsoft.Win32.SafeHandles;
 using System;
-using System.Buffers;
 using System.ComponentModel;
 using System.Diagnostics;
 using System.Net.Sockets;
@@ -56,58 +55,47 @@ public WinDivertPacket(int capacity = 0xFFFF + 40)
         {
             this.Capacity = capacity;
             this.handle = Marshal.AllocHGlobal(capacity);
-            this.Clear();
-        }
-
-        /// <summary>
-        /// 清除数据
-        /// </summary>
-        public void Clear()
-        {
             this.GetSpan(0, this.Capacity).Clear();
         }
 
         /// <summary>
-        /// 创建缓冲区写入对象
+        /// 释放本机句柄
         /// </summary>
-        /// <param name="offset">缓冲区偏移量</param>
-        /// <exception cref="ArgumentOutOfRangeException"></exception>
         /// <returns></returns>
-        public IBufferWriter<byte> CreateBufferWriter(int offset = 0)
+        protected override bool ReleaseHandle()
         {
-            return new BufferWriter(this, offset);
+            Marshal.FreeHGlobal(this.handle);
+            return true;
         }
 
         /// <summary>
-        /// 释放本机句柄
+        /// 将有效数据清0
         /// </summary>
-        /// <returns></returns>
-        protected override bool ReleaseHandle()
+        public void Clear()
         {
-            Marshal.FreeHGlobal(this.handle);
-            return true;
+            this.Span.Clear();
         }
 
         /// <summary>
-        /// 获取span
+        /// 获取缓冲区的Span
         /// </summary>
-        /// <param name="offset"></param>
-        /// <param name="sizeHint"></param>
+        /// <param name="offset">偏移量</param>
+        /// <param name="count">字节数</param>
         /// <returns></returns>
-        private unsafe Span<byte> GetSpan(int offset, int sizeHint)
+        public unsafe Span<byte> GetSpan(int offset, int count)
         {
-            if (offset > this.Capacity)
+            if (offset < 0 || offset > this.Capacity)
             {
                 throw new ArgumentOutOfRangeException(nameof(offset));
             }
 
-            if (this.Capacity - offset < sizeHint)
+            if (count < 0 || this.Capacity - offset < count)
             {
-                throw new ArgumentOutOfRangeException(nameof(sizeHint));
+                throw new ArgumentOutOfRangeException(nameof(count));
             }
 
             var pointer = (byte*)this.handle.ToPointer() + offset;
-            return new Span<byte>(pointer, sizeHint);
+            return new Span<byte>(pointer, count);
         }
 
         /// <summary>
@@ -203,43 +191,5 @@ public unsafe WinDivertParseResult GetParseResult()
                 NextLength = nextLength
             };
         }
-
-
-        private class BufferWriter : IBufferWriter<byte>
-        {
-            private int index;
-            private readonly WinDivertPacket packet;
-
-            public BufferWriter(WinDivertPacket packet, int offset)
-            {
-                if (offset >= packet.Capacity)
-                {
-                    throw new ArgumentOutOfRangeException(nameof(offset));
-                }
-
-                this.index = offset;
-                this.packet = packet;
-            }
-
-            public void Advance(int count)
-            {
-                this.index += count;
-                this.packet.Length = this.index;
-            }
-
-            public Span<byte> GetSpan(int sizeHint = 0)
-            {
-                if (sizeHint == 0)
-                {
-                    sizeHint = this.packet.Capacity - this.index;
-                }
-                return this.packet.GetSpan(this.index, sizeHint);
-            }
-
-            public Memory<byte> GetMemory(int sizeHint = 0)
-            {
-                throw new NotSupportedException();
-            }
-        }
     }
 }