// Copyright Keysight Technologies 2012-2019
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, you can obtain one at http://mozilla.org/MPL/2.0/.
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using System;
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using System.Linq;
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using System.Runtime.InteropServices;
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namespace OpenTap
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{
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/// <summary>
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/// Attempt to load VISA libraries from the system
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/// </summary>
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internal class VisaLibraryLoader : IVisaFunctionLoader
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{
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double IVisaFunctionLoader.Order => 10000;
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[DllImport("kernel32.dll")]
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static extern IntPtr LoadLibrary(string filename);
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[DllImport("kernel32.dll")]
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static extern IntPtr GetProcAddress(IntPtr hModule, string procname);
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static TraceSource staticLog = Log.CreateSource("VisaLibraryLoader");
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private unsafe delegate int ViReadDelegate(int vi, byte* buffer, int count, out int retCount);
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private ViReadDelegate viReadRef;
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private unsafe delegate int ViWriteDelegate(int vi, byte* buffer, int count, out int retCount);
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private ViWriteDelegate viWriteRef;
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public VisaLibraryLoader()
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{
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Functions = Load();
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}
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public unsafe int viRead(int vi, ArraySegment<byte> buffer, int count, out int retCount)
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{
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if (buffer.Count < count)
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throw new ArgumentException("Amount of bytes requested is larger than the space available in buffer.");
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fixed (byte* p = &buffer.Array[buffer.Offset])
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{
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return viReadRef(vi, p, count, out retCount);
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}
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}
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public unsafe int viWrite(int vi, ArraySegment<byte> buffer, int count, out int retCount)
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{
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if (buffer.Count < count)
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throw new ArgumentException("Amount of bytes requested to be written is larger than the space present in buffer.");
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fixed (byte* p = &buffer.Array[buffer.Offset])
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{
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return viWriteRef(vi, p, count, out retCount);
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}
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}
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public VisaFunctions? Functions { get; }
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// Required by .NET to catch AccessViolationException.
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[System.Runtime.ExceptionServices.HandleProcessCorruptedStateExceptions]
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public VisaFunctions? Load()
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{
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try
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{
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Func<string, IntPtr> loadSym;
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if (OperatingSystem.Current == OperatingSystem.Windows)
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{
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var libHandle = LoadLibrary("visa32.dll");
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loadSym = name => GetProcAddress(libHandle, name);
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}
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else if (OperatingSystem.Current == OperatingSystem.Linux)
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{
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string[] paths =
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{
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"./libvisa32.so", "./libvisa.so", "libvisa32.so", "libvisa.so", "libiovisa.so", "./libiovisa.so"
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};
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var libHandle = paths.Select(LibDl.Load).FirstOrDefault(x => x != IntPtr.Zero);
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loadSym = (name) => LibDl.Sym(libHandle, name);
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}
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else if (OperatingSystem.Current == OperatingSystem.MacOS)
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{
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string[] paths = { "./VISA", "/Library/Frameworks/VISA.framework/VISA" };
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var libHandle = paths.Select(LibDl.Load).FirstOrDefault(x => x != IntPtr.Zero);
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loadSym = (name) => LibDl.Sym(libHandle, name);
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}
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else
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{
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staticLog.Debug("Unknown OS: {0}", OpenTap.OperatingSystem.Current);
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return null;
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}
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var functions = new VisaFunctions();
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functions.ViOpenDefaultRmRef = GetSymbol<VisaFunctions.ViOpenDefaultRmDelegate>("viOpenDefaultRM");
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functions.ViFindRsrcRef = GetSymbol<VisaFunctions.ViFindRsrcDelegate>("viFindRsrc");
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functions.ViFindNextRef = GetSymbol<VisaFunctions.ViFindNextDelegate>("viFindNext");
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functions.ViParseRsrcRef = GetSymbol<VisaFunctions.ViParseRsrcDelegate>("viParseRsrc");
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functions.ViParseRsrcExRef = GetSymbol<VisaFunctions.ViParseRsrcExDelegate>("viParseRsrcEx");
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functions.ViOpenRef = GetSymbol<VisaFunctions.ViOpenDelegate>("viOpen");
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functions.ViCloseRef = GetSymbol<VisaFunctions.ViCloseDelegate>("viClose");
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functions.ViReadRef = viRead;
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viReadRef = GetSymbol<ViReadDelegate>("viRead");
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functions.ViWriteRef = viWrite;
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viWriteRef = GetSymbol<ViWriteDelegate>("viWrite");
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functions.ViReadStbRef = GetSymbol<VisaFunctions.ViReadStbDelegate>("viReadSTB");
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functions.ViClearRef = GetSymbol<VisaFunctions.ViClearDelegate>("viClear");
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functions.ViLockRef = GetSymbol<VisaFunctions.ViLockDelegate>("viLock");
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functions.ViUnlockRef = GetSymbol<VisaFunctions.ViUnlockDelegate>("viUnlock");
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functions.ViGetAttribute1Ref = GetSymbol<VisaFunctions.ViGetAttributeBDelegate>("viGetAttribute");
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functions.ViGetAttribute2Ref = GetSymbol<VisaFunctions.ViGetAttributeSbDelegate>("viGetAttribute");
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functions.ViGetAttribute3Ref = GetSymbol<VisaFunctions.ViGetAttributeIDelegate>("viGetAttribute");
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functions.ViSetAttribute1Ref = GetSymbol<VisaFunctions.ViSetAttributeBDelegate>("viSetAttribute");
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functions.ViSetAttribute2Ref = GetSymbol<VisaFunctions.ViSetAttributeIDelegate>("viSetAttribute");
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functions.ViStatusDescRef = GetSymbol<VisaFunctions.ViStatusDescDelegate>("viStatusDesc");
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functions.ViEnableEventRef = GetSymbol<VisaFunctions.ViEnableEventDelegate>("viEnableEvent");
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functions.ViDisableEventRef = GetSymbol<VisaFunctions.ViDisableEventDelegate>("viDisableEvent");
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functions.ViInstallHandlerRef = GetSymbol<VisaFunctions.ViInstallHandlerDelegate>("viInstallHandler");
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functions.ViUninstallHandlerRef = GetSymbol<VisaFunctions.ViUninstallHandlerDelegate>("viUninstallHandler");
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functions.ViWaitOnEventRef = GetSymbol<VisaFunctions.ViWaitOnEventDelegate>("viWaitOnEvent");
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return functions;
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T GetSymbol<T>(string str)
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{
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return Marshal.GetDelegateForFunctionPointer<T>(loadSym(str));
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}
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}
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catch (Exception ex)
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{
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staticLog.Debug("External VISA library not loaded: {0}", ex);
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return null;
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}
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}
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}
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}
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