Files
lmxopcua/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT/TwinCATArrayCodec.cs
T
Joseph Doherty f17ba8e258 feat(twincat): array and STRING writes through the codecs (U9)
Array tags were advertised writable but every write threw InvalidCastException
in ConvertForWrite (reported BadTypeMismatch); STRING writes went through the
Beckhoff marshaller with no length check against STRING(n) and the host's
ANSI code page, which the read side deliberately avoids.

- Array write: TwinCATArrayCodec.ToWriteElements converts exactly ArrayLength
  elements to the declared type (CLR lists convert - ScadaBridge writes int[]
  to Int16 nodes; a length mismatch or out-of-range element is BadOutOfRange, a
  scalar value BadTypeMismatch) before any wire traffic; the ADS client plans
  the layout from the resolved PLC array (TwinCATTypeGuard.CheckArray, as the
  read does), encodes with TwinCATArrayCodec.Encode - the exact inverse of
  Decode - and writes the raw bytes (new ITwinCATClient.WriteArrayAsync).
- STRING / WSTRING write: encoded at the PLC's declared width by
  TwinCATStringCodec.EncodeString/EncodeWString (Windows-1252 or UTF-8 per
  target, NUL-padded, strict: an over-long value or unrepresentable character
  is OverflowException -> BadOutOfRange) and written as raw bytes.
- TwinCAT CLI read/write gain --array-length (+ --separator) for the hardware
  gate.

Refs #739
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
2026-10-22 14:15:29 -04:00

217 lines
12 KiB
C#
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
using System.Buffers.Binary;
namespace ZB.MOM.WW.OtOpcUa.Driver.TwinCAT;
/// <summary>
/// Decodes a PLC array's raw bytes — laid out by <see cref="TwinCATTypeGuard.CheckArray"/> — into the
/// element-typed CLR array an array tag publishes (<c>bool[]</c>, <c>short[]</c>, <c>float[]</c>,
/// <c>string[]</c>, …). Both the poll read and the native notification decode here, so the two paths
/// publish identical values, element type and length by construction.
/// </summary>
/// <remarks>
/// The driver reads arrays as raw bytes rather than through the Beckhoff typed array read, which a live
/// TwinCAT 2.11 target showed failing for most real arrays (2026-10-07, Elma cleaner Z33856): the CLR
/// element type had to match the PLC's exactly (<c>ARRAY OF TIME</c> as <c>uint[]</c> threw), a
/// multi-dimensional array demanded a rank-N CLR array, and a dotted MEMBER array was sliced by the
/// under-reported symbol size (<c>ArgumentOutOfRangeException</c>). Elements are little-endian (every
/// TwinCAT target is x86/x64/ARM-LE); a STRING / WSTRING element is decoded by
/// <see cref="TwinCATStringCodec"/> within its fixed stride, so each ends at its own first NUL.
/// </remarks>
internal static class TwinCATArrayCodec
{
/// <summary>
/// Converts a client-supplied array value into exactly <paramref name="count"/> elements of the
/// declared type, each converted the way a scalar write converts (<see cref="AdsTwinCATClient.ConvertForWrite"/>
/// — so TIME/DATE elements become their encoded <c>uint</c>). Any CLR collection is accepted and the
/// element type is CONVERTED, not exact-matched: ScadaBridge writes an <c>int[]</c> to an Int16 node.
/// </summary>
/// <param name="declared">The tag's declared element type.</param>
/// <param name="value">The written value — an array or list.</param>
/// <param name="count">The tag's authored <c>ArrayLength</c>.</param>
/// <returns>The converted elements, in order.</returns>
/// <exception cref="InvalidCastException">The value is not a collection (a scalar, a string, null), or
/// an element cannot convert.</exception>
/// <exception cref="OverflowException">The element count differs from <paramref name="count"/>, or an
/// element is outside the declared type's range.</exception>
public static object[] ToWriteElements(TwinCATDataType declared, object? value, int count)
{
if (value is null or string || value is not System.Collections.IEnumerable items)
throw new InvalidCastException(
$"an array tag of {count} {declared} takes an array value, not {value?.GetType().Name ?? "null"}");
var elements = new List<object>(count);
foreach (var item in items) elements.Add(AdsTwinCATClient.ConvertForWrite(declared, item));
if (elements.Count != count)
throw new OverflowException($"wrote {elements.Count} elements to an array tag of arrayLength {count}");
return [.. elements];
}
/// <summary>
/// Encodes converted elements (<see cref="ToWriteElements"/>) into the PLC's raw bytes at the planned
/// layout — the exact inverse of <see cref="Decode"/>: little-endian at the element stride, a
/// STRING / WSTRING element encoded by <see cref="TwinCATStringCodec"/> within its fixed stride.
/// </summary>
/// <param name="declared">The tag's declared element type.</param>
/// <param name="elements">The converted elements; exactly <see cref="TwinCATArrayLayout.ElementCount"/>.</param>
/// <param name="layout">The layout planned from the PLC array (<see cref="TwinCATTypeGuard.CheckArray"/>).</param>
/// <param name="utf8">True when the target reports UTF-8 STRING data (else Windows-1252).</param>
/// <returns>Exactly <see cref="TwinCATArrayLayout.ByteLength"/> bytes.</returns>
/// <exception cref="ArgumentException">The element count differs from the layout.</exception>
/// <exception cref="OverflowException">A string element does not fit its stride.</exception>
public static byte[] Encode(TwinCATDataType declared, IReadOnlyList<object> elements, TwinCATArrayLayout layout, bool utf8)
{
if (layout.Stride <= 0 || elements.Count != layout.ElementCount)
throw new ArgumentException(
$"{elements.Count} elements do not match a layout of {layout.ElementCount} × {layout.Stride} B", nameof(elements));
var bytes = new byte[layout.ByteLength];
var stride = layout.Stride;
for (var i = 0; i < elements.Count; i++)
{
var slot = bytes.AsSpan(i * stride, stride);
var e = elements[i];
switch (declared)
{
case TwinCATDataType.Bool: slot[0] = Convert.ToBoolean(e) ? (byte)1 : (byte)0; break;
case TwinCATDataType.SInt: slot[0] = unchecked((byte)Convert.ToSByte(e)); break;
case TwinCATDataType.USInt: slot[0] = Convert.ToByte(e); break;
case TwinCATDataType.Int: BinaryPrimitives.WriteInt16LittleEndian(slot, Convert.ToInt16(e)); break;
case TwinCATDataType.UInt: BinaryPrimitives.WriteUInt16LittleEndian(slot, Convert.ToUInt16(e)); break;
case TwinCATDataType.DInt: BinaryPrimitives.WriteInt32LittleEndian(slot, Convert.ToInt32(e)); break;
case TwinCATDataType.UDInt or TwinCATDataType.Time or TwinCATDataType.TimeOfDay
or TwinCATDataType.Date or TwinCATDataType.DateTime:
BinaryPrimitives.WriteUInt32LittleEndian(slot, Convert.ToUInt32(e)); break;
case TwinCATDataType.LInt: BinaryPrimitives.WriteInt64LittleEndian(slot, Convert.ToInt64(e)); break;
case TwinCATDataType.ULInt: BinaryPrimitives.WriteUInt64LittleEndian(slot, Convert.ToUInt64(e)); break;
case TwinCATDataType.Real: BinaryPrimitives.WriteSingleLittleEndian(slot, Convert.ToSingle(e)); break;
case TwinCATDataType.LReal: BinaryPrimitives.WriteDoubleLittleEndian(slot, Convert.ToDouble(e)); break;
case TwinCATDataType.String:
TwinCATStringCodec.EncodeString(Convert.ToString(e) ?? string.Empty, stride, utf8).CopyTo(slot);
break;
case TwinCATDataType.WString:
TwinCATStringCodec.EncodeWString(Convert.ToString(e) ?? string.Empty, stride).CopyTo(slot);
break;
default:
throw new NotSupportedException($"TwinCATDataType {declared} has no array element encoding");
}
}
return bytes;
}
/// <summary>Decodes <paramref name="layout"/>.ElementCount elements of <paramref name="declared"/>.</summary>
/// <param name="declared">The tag's declared element type.</param>
/// <param name="bytes">The PLC bytes from the array's first element (at least <see cref="TwinCATArrayLayout.ByteLength"/>).</param>
/// <param name="layout">The planned layout.</param>
/// <param name="utf8">True when the target reports UTF-8 STRING data (else Windows-1252).</param>
/// <returns>The element-typed CLR array.</returns>
/// <exception cref="ArgumentException">The buffer is shorter than the layout.</exception>
public static Array Decode(TwinCATDataType declared, ReadOnlySpan<byte> bytes, TwinCATArrayLayout layout, bool utf8)
{
if (layout.ElementCount < 0 || layout.Stride <= 0 || bytes.Length < layout.ByteLength)
throw new ArgumentException(
$"An array buffer of {bytes.Length} B cannot hold {layout.ElementCount} × {layout.Stride} B elements",
nameof(bytes));
var n = layout.ElementCount;
var stride = layout.Stride;
switch (declared)
{
case TwinCATDataType.Bool:
{
var a = new bool[n];
for (var i = 0; i < n; i++) a[i] = bytes[i * stride] != 0;
return a;
}
case TwinCATDataType.SInt:
{
var a = new sbyte[n];
for (var i = 0; i < n; i++) a[i] = unchecked((sbyte)bytes[i * stride]);
return a;
}
case TwinCATDataType.USInt:
{
var a = new byte[n];
for (var i = 0; i < n; i++) a[i] = bytes[i * stride];
return a;
}
case TwinCATDataType.Int:
{
var a = new short[n];
for (var i = 0; i < n; i++) a[i] = BinaryPrimitives.ReadInt16LittleEndian(bytes[(i * stride)..]);
return a;
}
case TwinCATDataType.UInt:
{
var a = new ushort[n];
for (var i = 0; i < n; i++) a[i] = BinaryPrimitives.ReadUInt16LittleEndian(bytes[(i * stride)..]);
return a;
}
case TwinCATDataType.DInt:
{
var a = new int[n];
for (var i = 0; i < n; i++) a[i] = BinaryPrimitives.ReadInt32LittleEndian(bytes[(i * stride)..]);
return a;
}
case TwinCATDataType.UDInt:
{
var a = new uint[n];
for (var i = 0; i < n; i++) a[i] = BinaryPrimitives.ReadUInt32LittleEndian(bytes[(i * stride)..]);
return a;
}
case TwinCATDataType.Time or TwinCATDataType.TimeOfDay:
{
// TIME / TOD publish milliseconds as double — the same CLR shape a scalar publishes.
var a = new double[n];
for (var i = 0; i < n; i++)
a[i] = (double)TwinCATTemporalCodec.Decode(declared, BinaryPrimitives.ReadUInt32LittleEndian(bytes[(i * stride)..]));
return a;
}
case TwinCATDataType.Date or TwinCATDataType.DateTime:
{
// DATE / DT publish a UTC DateTime, as a scalar does.
var a = new DateTime[n];
for (var i = 0; i < n; i++)
a[i] = (DateTime)TwinCATTemporalCodec.Decode(declared, BinaryPrimitives.ReadUInt32LittleEndian(bytes[(i * stride)..]));
return a;
}
case TwinCATDataType.LInt:
{
var a = new long[n];
for (var i = 0; i < n; i++) a[i] = BinaryPrimitives.ReadInt64LittleEndian(bytes[(i * stride)..]);
return a;
}
case TwinCATDataType.ULInt:
{
var a = new ulong[n];
for (var i = 0; i < n; i++) a[i] = BinaryPrimitives.ReadUInt64LittleEndian(bytes[(i * stride)..]);
return a;
}
case TwinCATDataType.Real:
{
var a = new float[n];
for (var i = 0; i < n; i++) a[i] = BinaryPrimitives.ReadSingleLittleEndian(bytes[(i * stride)..]);
return a;
}
case TwinCATDataType.LReal:
{
var a = new double[n];
for (var i = 0; i < n; i++) a[i] = BinaryPrimitives.ReadDoubleLittleEndian(bytes[(i * stride)..]);
return a;
}
case TwinCATDataType.String:
{
var a = new string[n];
for (var i = 0; i < n; i++) a[i] = TwinCATStringCodec.DecodeString(bytes.Slice(i * stride, stride), utf8);
return a;
}
case TwinCATDataType.WString:
{
var a = new string[n];
for (var i = 0; i < n; i++) a[i] = TwinCATStringCodec.DecodeWString(bytes.Slice(i * stride, stride));
return a;
}
default:
throw new NotSupportedException($"TwinCATDataType {declared} has no array element decoding");
}
}
}