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Use System.Memory for < .NET 5 and avoid (some) unnecessary allocations

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This commit is contained in:
Günther Foidl
2023-05-30 17:25:25 +02:00
parent ab70bfb041
commit 209148ab02
5 changed files with 81 additions and 233 deletions
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24
S7.Net/Helper/MemoryStreamExtension.cs
View File

@@ -1,6 +1,10 @@

using System;
using System.Buffers;
using System.IO;
namespace S7.Net.Helper
{
#if !NET5_0_OR_GREATER
internal static class MemoryStreamExtension
{
/// <summary>
@@ -10,9 +14,25 @@ namespace S7.Net.Helper
/// </summary>
/// <param name="stream"></param>
/// <param name="value"></param>
public static void WriteByteArray(this System.IO.MemoryStream stream, byte[] value)
public static void Write(this MemoryStream stream, byte[] value)
{
stream.Write(value, 0, value.Length);
}
/// <summary>
/// Helper function to write the whole content of the given byte span to a memory stream.
/// </summary>
/// <param name="stream"></param>
/// <param name="value"></param>
public static void Write(this MemoryStream stream, ReadOnlySpan<byte> value)
{
byte[] buffer = ArrayPool<byte>.Shared.Rent(value.Length);
value.CopyTo(buffer);
stream.Write(buffer, 0, value.Length);
ArrayPool<byte>.Shared.Return(buffer);
}
}
#endif
}

21
S7.Net/PLCHelpers.cs
View File

@@ -1,7 +1,6 @@
using S7.Net.Helper;
using S7.Net.Protocol.S7;
using S7.Net.Types;
using System;
using System.Collections.Generic;
using System.Linq;
using DateTime = S7.Net.Types.DateTime;
@@ -18,13 +17,13 @@ namespace S7.Net
private static void BuildHeaderPackage(System.IO.MemoryStream stream, int amount = 1)
{
//header size = 19 bytes
stream.WriteByteArray(new byte[] { 0x03, 0x00 });
stream.Write(new byte[] { 0x03, 0x00 });
//complete package size
stream.WriteByteArray(Types.Int.ToByteArray((short)(19 + (12 * amount))));
stream.WriteByteArray(new byte[] { 0x02, 0xf0, 0x80, 0x32, 0x01, 0x00, 0x00, 0x00, 0x00 });
stream.Write(Int.ToByteArray((short)(19 + (12 * amount))));
stream.Write(new byte[] { 0x02, 0xf0, 0x80, 0x32, 0x01, 0x00, 0x00, 0x00, 0x00 });
//data part size
stream.WriteByteArray(Types.Word.ToByteArray((ushort)(2 + (amount * 12))));
stream.WriteByteArray(new byte[] { 0x00, 0x00, 0x04 });
stream.Write(Word.ToByteArray((ushort)(2 + (amount * 12))));
stream.Write(new byte[] { 0x00, 0x00, 0x04 });
//amount of requests
stream.WriteByte((byte)amount);
}
@@ -41,7 +40,7 @@ namespace S7.Net
private static void BuildReadDataRequestPackage(System.IO.MemoryStream stream, DataType dataType, int db, int startByteAdr, int count = 1)
{
//single data req = 12
stream.WriteByteArray(new byte[] { 0x12, 0x0a, 0x10 });
stream.Write(new byte[] { 0x12, 0x0a, 0x10 });
switch (dataType)
{
case DataType.Timer:
@@ -53,8 +52,8 @@ namespace S7.Net
break;
}
stream.WriteByteArray(Word.ToByteArray((ushort)(count)));
stream.WriteByteArray(Word.ToByteArray((ushort)(db)));
stream.Write(Word.ToByteArray((ushort)(count)));
stream.Write(Word.ToByteArray((ushort)(db)));
stream.WriteByte((byte)dataType);
var overflow = (int)(startByteAdr * 8 / 0xffffU); // handles words with address bigger than 8191
stream.WriteByte((byte)overflow);
@@ -62,10 +61,10 @@ namespace S7.Net
{
case DataType.Timer:
case DataType.Counter:
stream.WriteByteArray(Types.Word.ToByteArray((ushort)(startByteAdr)));
stream.Write(Word.ToByteArray((ushort)(startByteAdr)));
break;
default:
stream.WriteByteArray(Types.Word.ToByteArray((ushort)((startByteAdr) * 8)));
stream.Write(Word.ToByteArray((ushort)((startByteAdr) * 8)));
break;
}
}

79
S7.Net/PlcAsynchronous.cs
View File

@@ -95,7 +95,6 @@ namespace S7.Net
MaxPDUSize = s7data[18] * 256 + s7data[19];
}
/// <summary>
/// Reads a number of bytes from a DB starting from a specified index. This handles more than 200 bytes with multiple requests.
/// If the read was not successful, check LastErrorCode or LastErrorString.
@@ -110,20 +109,12 @@ namespace S7.Net
public async Task<byte[]> ReadBytesAsync(DataType dataType, int db, int startByteAdr, int count, CancellationToken cancellationToken = default)
{
var resultBytes = new byte[count];
int index = 0;
while (count > 0)
{
//This works up to MaxPDUSize-1 on SNAP7. But not MaxPDUSize-0.
var maxToRead = Math.Min(count, MaxPDUSize - 18);
await ReadBytesWithSingleRequestAsync(dataType, db, startByteAdr + index, resultBytes, index, maxToRead, cancellationToken).ConfigureAwait(false);
count -= maxToRead;
index += maxToRead;
}
await ReadBytesAsync(resultBytes, dataType, db, startByteAdr, cancellationToken).ConfigureAwait(false);
return resultBytes;
}
#if NET5_0_OR_GREATER
/// <summary>
/// Reads a number of bytes from a DB starting from a specified index. This handles more than 200 bytes with multiple requests.
/// If the read was not successful, check LastErrorCode or LastErrorString.
@@ -148,8 +139,6 @@ namespace S7.Net
}
}
#endif
/// <summary>
/// Read and decode a certain number of bytes of the "VarType" provided.
/// This can be used to read multiple consecutive variables of the same type (Word, DWord, Int, etc).
@@ -323,7 +312,6 @@ namespace S7.Net
return dataItems;
}
/// <summary>
/// Write a number of bytes from a DB starting from a specified index. This handles more than 200 bytes with multiple requests.
/// If the write was not successful, check LastErrorCode or LastErrorString.
@@ -335,20 +323,10 @@ namespace S7.Net
/// <param name="cancellationToken">The token to monitor for cancellation requests. The default value is None.
/// Please note that cancellation is advisory/cooperative and will not lead to immediate cancellation in all cases.</param>
/// <returns>A task that represents the asynchronous write operation.</returns>
public async Task WriteBytesAsync(DataType dataType, int db, int startByteAdr, byte[] value, CancellationToken cancellationToken = default)
public Task WriteBytesAsync(DataType dataType, int db, int startByteAdr, byte[] value, CancellationToken cancellationToken = default)
{
int localIndex = 0;
int count = value.Length;
while (count > 0)
{
var maxToWrite = (int)Math.Min(count, MaxPDUSize - 35);
await WriteBytesWithASingleRequestAsync(dataType, db, startByteAdr + localIndex, value, localIndex, maxToWrite, cancellationToken).ConfigureAwait(false);
count -= maxToWrite;
localIndex += maxToWrite;
return WriteBytesAsync(dataType, db, startByteAdr, value.AsMemory(), cancellationToken);
}
}
#if NET5_0_OR_GREATER
/// <summary>
/// Write a number of bytes from a DB starting from a specified index. This handles more than 200 bytes with multiple requests.
@@ -373,8 +351,6 @@ namespace S7.Net
}
}
#endif
/// <summary>
/// Write a single bit from a DB with the specified index.
/// </summary>
@@ -496,18 +472,6 @@ namespace S7.Net
await WriteBytesAsync(DataType.DataBlock, db, startByteAdr, bytes, cancellationToken).ConfigureAwait(false);
}
private async Task ReadBytesWithSingleRequestAsync(DataType dataType, int db, int startByteAdr, byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
var dataToSend = BuildReadRequestPackage(new[] { new DataItemAddress(dataType, db, startByteAdr, count) });
var s7data = await RequestTsduAsync(dataToSend, cancellationToken);
AssertReadResponse(s7data, count);
Array.Copy(s7data, 18, buffer, offset, count);
}
#if NET5_0_OR_GREATER
private async Task ReadBytesWithSingleRequestAsync(DataType dataType, int db, int startByteAdr, Memory<byte> buffer, CancellationToken cancellationToken)
{
var dataToSend = BuildReadRequestPackage(new[] { new DataItemAddress(dataType, db, startByteAdr, buffer.Length) });
@@ -518,8 +482,6 @@ namespace S7.Net
s7data.AsSpan(18, buffer.Length).CopyTo(buffer.Span);
}
#endif
/// <summary>
/// Write DataItem(s) to the PLC. Throws an exception if the response is invalid
/// or when the PLC reports errors for item(s) written.
@@ -538,35 +500,6 @@ namespace S7.Net
S7WriteMultiple.ParseResponse(response, response.Length, dataItems);
}
/// <summary>
/// Writes up to 200 bytes to the PLC. You must specify the memory area type, memory are address, byte start address and bytes count.
/// </summary>
/// <param name="dataType">Data type of the memory area, can be DB, Timer, Counter, Merker(Memory), Input, Output.</param>
/// <param name="db">Address of the memory area (if you want to read DB1, this is set to 1). This must be set also for other memory area types: counters, timers,etc.</param>
/// <param name="startByteAdr">Start byte address. If you want to read DB1.DBW200, this is 200.</param>
/// <param name="value">Bytes to write. The lenght of this parameter can't be higher than 200. If you need more, use recursion.</param>
/// <returns>A task that represents the asynchronous write operation.</returns>
private async Task WriteBytesWithASingleRequestAsync(DataType dataType, int db, int startByteAdr, byte[] value, int dataOffset, int count, CancellationToken cancellationToken)
{
try
{
var dataToSend = BuildWriteBytesPackage(dataType, db, startByteAdr, value, dataOffset, count);
var s7data = await RequestTsduAsync(dataToSend, cancellationToken).ConfigureAwait(false);
ValidateResponseCode((ReadWriteErrorCode)s7data[14]);
}
catch (OperationCanceledException)
{
throw;
}
catch (Exception exc)
{
throw new PlcException(ErrorCode.WriteData, exc);
}
}
#if NET5_0_OR_GREATER
/// <summary>
/// Writes up to 200 bytes to the PLC. You must specify the memory area type, memory are address, byte start address and bytes count.
/// </summary>
@@ -594,8 +527,6 @@ namespace S7.Net
}
}
#endif
private async Task WriteBitWithASingleRequestAsync(DataType dataType, int db, int startByteAdr, int bitAdr, bool bitValue, CancellationToken cancellationToken)
{
try

186
S7.Net/PlcSynchronous.cs
View File

@@ -39,20 +39,12 @@ namespace S7.Net
public byte[] ReadBytes(DataType dataType, int db, int startByteAdr, int count)
{
var result = new byte[count];
int index = 0;
while (count > 0)
{
//This works up to MaxPDUSize-1 on SNAP7. But not MaxPDUSize-0.
var maxToRead = Math.Min(count, MaxPDUSize - 18);
ReadBytesWithSingleRequest(dataType, db, startByteAdr + index, result, index, maxToRead);
count -= maxToRead;
index += maxToRead;
}
ReadBytes(result, dataType, db, startByteAdr);
return result;
}
#if NET5_0_OR_GREATER
/// <summary>
/// Reads a number of bytes from a DB starting from a specified index. This handles more than 200 bytes with multiple requests.
/// If the read was not successful, check LastErrorCode or LastErrorString.
@@ -75,8 +67,6 @@ namespace S7.Net
}
}
#endif
/// <summary>
/// Read and decode a certain number of bytes of the "VarType" provided.
/// This can be used to read multiple consecutive variables of the same type (Word, DWord, Int, etc).
@@ -137,7 +127,6 @@ namespace S7.Net
return ReadStruct(typeof(T), db, startByteAdr) as T?;
}
/// <summary>
/// Reads all the bytes needed to fill a class in C#, starting from a certain address, and set all the properties values to the value that are read from the PLC.
/// This reads only properties, it doesn't read private variable or public variable without {get;set;} specified.
@@ -205,21 +194,8 @@ namespace S7.Net
/// <param name="value">Bytes to write. If more than 200, multiple requests will be made.</param>
public void WriteBytes(DataType dataType, int db, int startByteAdr, byte[] value)
{
int localIndex = 0;
int count = value.Length;
while (count > 0)
{
//TODO: Figure out how to use MaxPDUSize here
//Snap7 seems to choke on PDU sizes above 256 even if snap7
//replies with bigger PDU size in connection setup.
var maxToWrite = Math.Min(count, MaxPDUSize - 28);//TODO tested only when the MaxPDUSize is 480
WriteBytesWithASingleRequest(dataType, db, startByteAdr + localIndex, value, localIndex, maxToWrite);
count -= maxToWrite;
localIndex += maxToWrite;
WriteBytes(dataType, db, startByteAdr, value.AsSpan());
}
}
#if NET5_0_OR_GREATER
/// <summary>
/// Write a number of bytes from a DB starting from a specified index. This handles more than 200 bytes with multiple requests.
@@ -244,8 +220,6 @@ namespace S7.Net
}
}
#endif
/// <summary>
/// Write a single bit from a DB with the specified index.
/// </summary>
@@ -347,43 +321,18 @@ namespace S7.Net
WriteClassAsync(classValue, db, startByteAdr).GetAwaiter().GetResult();
}
private void ReadBytesWithSingleRequest(DataType dataType, int db, int startByteAdr, byte[] buffer, int offset, int count)
{
try
{
// first create the header
int packageSize = 19 + 12; // 19 header + 12 for 1 request
var package = new System.IO.MemoryStream(packageSize);
BuildHeaderPackage(package);
// package.Add(0x02); // datenart
BuildReadDataRequestPackage(package, dataType, db, startByteAdr, count);
var dataToSend = package.ToArray();
var s7data = RequestTsdu(dataToSend);
AssertReadResponse(s7data, count);
Array.Copy(s7data, 18, buffer, offset, count);
}
catch (Exception exc)
{
throw new PlcException(ErrorCode.ReadData, exc);
}
}
#if NET5_0_OR_GREATER
private void ReadBytesWithSingleRequest(DataType dataType, int db, int startByteAdr, Span<byte> buffer)
{
try
{
// first create the header
int packageSize = 19 + 12; // 19 header + 12 for 1 request
var package = new System.IO.MemoryStream(packageSize);
const int packageSize = 19 + 12; // 19 header + 12 for 1 request
var dataToSend = new byte[packageSize];
var package = new MemoryStream(dataToSend);
BuildHeaderPackage(package);
// package.Add(0x02); // datenart
BuildReadDataRequestPackage(package, dataType, db, startByteAdr, buffer.Length);
var dataToSend = package.ToArray();
var s7data = RequestTsdu(dataToSend);
AssertReadResponse(s7data, buffer.Length);
@@ -395,8 +344,6 @@ namespace S7.Net
}
}
#endif
/// <summary>
/// Write DataItem(s) to the PLC. Throws an exception if the response is invalid
/// or when the PLC reports errors for item(s) written.
@@ -406,7 +353,6 @@ namespace S7.Net
{
AssertPduSizeForWrite(dataItems);
var message = new ByteArray();
var length = S7WriteMultiple.CreateRequest(message, dataItems);
var response = RequestTsdu(message.Array, 0, length);
@@ -414,23 +360,6 @@ namespace S7.Net
S7WriteMultiple.ParseResponse(response, response.Length, dataItems);
}
private void WriteBytesWithASingleRequest(DataType dataType, int db, int startByteAdr, byte[] value, int dataOffset, int count)
{
try
{
var dataToSend = BuildWriteBytesPackage(dataType, db, startByteAdr, value, dataOffset, count);
var s7data = RequestTsdu(dataToSend);
ValidateResponseCode((ReadWriteErrorCode)s7data[14]);
}
catch (Exception exc)
{
throw new PlcException(ErrorCode.WriteData, exc);
}
}
#if NET5_0_OR_GREATER
private void WriteBytesWithASingleRequest(DataType dataType, int db, int startByteAdr, ReadOnlySpan<byte> value)
{
try
@@ -446,107 +375,72 @@ namespace S7.Net
}
}
#endif
private byte[] BuildWriteBytesPackage(DataType dataType, int db, int startByteAdr, byte[] value, int dataOffset, int count)
{
int varCount = count;
// first create the header
int packageSize = 35 + varCount;
var package = new MemoryStream(new byte[packageSize]);
package.WriteByte(3);
package.WriteByte(0);
//complete package size
package.WriteByteArray(Int.ToByteArray((short)packageSize));
package.WriteByteArray(new byte[] { 2, 0xf0, 0x80, 0x32, 1, 0, 0 });
package.WriteByteArray(Word.ToByteArray((ushort)(varCount - 1)));
package.WriteByteArray(new byte[] { 0, 0x0e });
package.WriteByteArray(Word.ToByteArray((ushort)(varCount + 4)));
package.WriteByteArray(new byte[] { 0x05, 0x01, 0x12, 0x0a, 0x10, 0x02 });
package.WriteByteArray(Word.ToByteArray((ushort)varCount));
package.WriteByteArray(Word.ToByteArray((ushort)(db)));
package.WriteByte((byte)dataType);
var overflow = (int)(startByteAdr * 8 / 0xffffU); // handles words with address bigger than 8191
package.WriteByte((byte)overflow);
package.WriteByteArray(Word.ToByteArray((ushort)(startByteAdr * 8)));
package.WriteByteArray(new byte[] { 0, 4 });
package.WriteByteArray(Word.ToByteArray((ushort)(varCount * 8)));
// now join the header and the data
package.Write(value, dataOffset, count);
return package.ToArray();
}
#if NET5_0_OR_GREATER
private byte[] BuildWriteBytesPackage(DataType dataType, int db, int startByteAdr, ReadOnlySpan<byte> value)
{
int varCount = value.Length;
// first create the header
int packageSize = 35 + varCount;
var package = new MemoryStream(new byte[packageSize]);
var packageData = new byte[packageSize];
var package = new MemoryStream(packageData);
package.WriteByte(3);
package.WriteByte(0);
//complete package size
package.WriteByteArray(Int.ToByteArray((short)packageSize));
package.WriteByteArray(new byte[] { 2, 0xf0, 0x80, 0x32, 1, 0, 0 });
package.WriteByteArray(Word.ToByteArray((ushort)(varCount - 1)));
package.WriteByteArray(new byte[] { 0, 0x0e });
package.WriteByteArray(Word.ToByteArray((ushort)(varCount + 4)));
package.WriteByteArray(new byte[] { 0x05, 0x01, 0x12, 0x0a, 0x10, 0x02 });
package.WriteByteArray(Word.ToByteArray((ushort)varCount));
package.WriteByteArray(Word.ToByteArray((ushort)(db)));
package.Write(Int.ToByteArray((short)packageSize));
// This overload doesn't allocate the byte array, it refers to assembly's static data segment
package.Write(new byte[] { 2, 0xf0, 0x80, 0x32, 1, 0, 0 });
package.Write(Word.ToByteArray((ushort)(varCount - 1)));
package.Write(new byte[] { 0, 0x0e });
package.Write(Word.ToByteArray((ushort)(varCount + 4)));
package.Write(new byte[] { 0x05, 0x01, 0x12, 0x0a, 0x10, 0x02 });
package.Write(Word.ToByteArray((ushort)varCount));
package.Write(Word.ToByteArray((ushort)(db)));
package.WriteByte((byte)dataType);
var overflow = (int)(startByteAdr * 8 / 0xffffU); // handles words with address bigger than 8191
package.WriteByte((byte)overflow);
package.WriteByteArray(Word.ToByteArray((ushort)(startByteAdr * 8)));
package.WriteByteArray(new byte[] { 0, 4 });
package.WriteByteArray(Word.ToByteArray((ushort)(varCount * 8)));
package.Write(Word.ToByteArray((ushort)(startByteAdr * 8)));
package.Write(new byte[] { 0, 4 });
package.Write(Word.ToByteArray((ushort)(varCount * 8)));
// now join the header and the data
package.Write(value);
return package.ToArray();
return packageData;
}
#endif
private byte[] BuildWriteBitPackage(DataType dataType, int db, int startByteAdr, bool bitValue, int bitAdr)
{
var value = new[] { bitValue ? (byte)1 : (byte)0 };
int varCount = 1;
// first create the header
int packageSize = 35 + varCount;
var package = new MemoryStream(new byte[packageSize]);
var packageData = new byte[packageSize];
var package = new MemoryStream(packageData);
package.WriteByte(3);
package.WriteByte(0);
//complete package size
package.WriteByteArray(Int.ToByteArray((short)packageSize));
package.WriteByteArray(new byte[] { 2, 0xf0, 0x80, 0x32, 1, 0, 0 });
package.WriteByteArray(Word.ToByteArray((ushort)(varCount - 1)));
package.WriteByteArray(new byte[] { 0, 0x0e });
package.WriteByteArray(Word.ToByteArray((ushort)(varCount + 4)));
package.WriteByteArray(new byte[] { 0x05, 0x01, 0x12, 0x0a, 0x10, 0x01 }); //ending 0x01 is used for writing a sinlge bit
package.WriteByteArray(Word.ToByteArray((ushort)varCount));
package.WriteByteArray(Word.ToByteArray((ushort)(db)));
package.Write(Int.ToByteArray((short)packageSize));
package.Write(new byte[] { 2, 0xf0, 0x80, 0x32, 1, 0, 0 });
package.Write(Word.ToByteArray((ushort)(varCount - 1)));
package.Write(new byte[] { 0, 0x0e });
package.Write(Word.ToByteArray((ushort)(varCount + 4)));
package.Write(new byte[] { 0x05, 0x01, 0x12, 0x0a, 0x10, 0x01 }); //ending 0x01 is used for writing a sinlge bit
package.Write(Word.ToByteArray((ushort)varCount));
package.Write(Word.ToByteArray((ushort)(db)));
package.WriteByte((byte)dataType);
var overflow = (int)(startByteAdr * 8 / 0xffffU); // handles words with address bigger than 8191
package.WriteByte((byte)overflow);
package.WriteByteArray(Word.ToByteArray((ushort)(startByteAdr * 8 + bitAdr)));
package.WriteByteArray(new byte[] { 0, 0x03 }); //ending 0x03 is used for writing a sinlge bit
package.WriteByteArray(Word.ToByteArray((ushort)(varCount)));
package.Write(Word.ToByteArray((ushort)(startByteAdr * 8 + bitAdr)));
package.Write(new byte[] { 0, 0x03 }); //ending 0x03 is used for writing a sinlge bit
package.Write(Word.ToByteArray((ushort)(varCount)));
// now join the header and the data
package.WriteByteArray(value);
package.Write(value);
return package.ToArray();
return packageData;
}
private void WriteBitWithASingleRequest(DataType dataType, int db, int startByteAdr, int bitAdr, bool bitValue)
{
try
@@ -578,7 +472,8 @@ namespace S7.Net
{
// first create the header
int packageSize = 19 + (dataItems.Count * 12);
var package = new System.IO.MemoryStream(packageSize);
var dataToSend = new byte[packageSize];
var package = new MemoryStream(dataToSend);
BuildHeaderPackage(package, dataItems.Count);
// package.Add(0x02); // datenart
foreach (var dataItem in dataItems)
@@ -586,8 +481,7 @@ namespace S7.Net
BuildReadDataRequestPackage(package, dataItem.DataType, dataItem.DB, dataItem.StartByteAdr, VarTypeToByteLength(dataItem.VarType, dataItem.Count));
}
var dataToSend = package.ToArray();
var s7data = RequestTsdu(dataToSend);
byte[] s7data = RequestTsdu(dataToSend);
ValidateResponseCode((ReadWriteErrorCode)s7data[14]);

4
S7.Net/S7.Net.csproj
View File

@@ -27,6 +27,10 @@
<DefineConstants>NET_FULL</DefineConstants>
</PropertyGroup>
<ItemGroup Condition="'$(TargetFramework)' != 'net5.0'">
<PackageReference Include="System.Memory" Version="4.5.5" />
</ItemGroup>
<ItemGroup>
<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="All" />
</ItemGroup>