EXECUTION-TIME CODE GENERATION in C#

Generation PDF417 in C# EXECUTION-TIME CODE GENERATION

CHAPTER 32 EXECUTION-TIME CODE GENERATION
Drawing PDF-417 2d Barcode In C#.NET
Using Barcode generation for .NET Control to generate, create PDF417 image in Visual Studio .NET applications.
www.OnBarcode.com
Scan PDF-417 2d Barcode In Visual C#
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
// // Hook up the interface member to the member function // that implements that member. // 1) Get the interface member. // 2) Hook the method to the interface member. // MethodInfo methodInterfaceEval = typeof(IPolynomial).GetMethod("Evaluate"); myType.DefineMethodOverride(simpleMethod, methodInterfaceEval); myType.CreateType(); return newAssembly; } public void Setup() { // Create the assembly, create an instance of the // evalution class, and save away an interface // reference to it. Assembly ass = EmitAssembly(); theObject = ass.CreateInstance("PolyEvaluate"); theType = theObject.GetType(); poly = (IPolynomial) theObject; } public override IPolynomial GetEvaluate() { if (theType == null) Setup(); return((IPolynomial) poly); } public override double Evaluate(double value) { return(0.0f); } } The best way to understand this code is to look at the ILDASM for the previous example, walk through the code, look up the classes in the documentation, and read the comments.
Encoding 2D Barcode In C#.NET
Using Barcode printer for .NET Control to generate, create Matrix Barcode image in .NET applications.
www.OnBarcode.com
Printing EAN13 In Visual C#
Using Barcode encoder for VS .NET Control to generate, create GS1 - 13 image in .NET applications.
www.OnBarcode.com
CHAPTER 32 EXECUTION-TIME CODE GENERATION
Create 1D In Visual C#.NET
Using Barcode generator for Visual Studio .NET Control to generate, create 1D Barcode image in .NET applications.
www.OnBarcode.com
Generating PDF-417 2d Barcode In Visual C#
Using Barcode generator for .NET framework Control to generate, create PDF 417 image in .NET framework applications.
www.OnBarcode.com
The implementation using Reflection.Emit has nearly identical performance to the other fast techniques but less overhead (about 0.25 seconds for the first polynomial and no measurable overhead for later ones). Table 32-4 shows the final results.
Painting Data Matrix ECC200 In C#.NET
Using Barcode drawer for .NET Control to generate, create ECC200 image in .NET framework applications.
www.OnBarcode.com
Create C 2 Of 5 In Visual C#
Using Barcode maker for .NET Control to generate, create Code 2/5 image in .NET framework applications.
www.OnBarcode.com
Table 32-4. Results Summary
Making PDF 417 In VS .NET
Using Barcode creator for Reporting Service Control to generate, create PDF417 image in Reporting Service applications.
www.OnBarcode.com
Encode PDF-417 2d Barcode In Java
Using Barcode printer for BIRT reports Control to generate, create PDF-417 2d barcode image in BIRT applications.
www.OnBarcode.com
Method
Print Data Matrix ECC200 In .NET
Using Barcode maker for ASP.NET Control to generate, create Data Matrix 2d barcode image in ASP.NET applications.
www.OnBarcode.com
Barcode Recognizer In .NET Framework
Using Barcode Control SDK for ASP.NET Control to generate, create, read, scan barcode image in ASP.NET applications.
www.OnBarcode.com
Simple Custom Custom fast CodeDOM
Encoding PDF417 In VS .NET
Using Barcode generation for Reporting Service Control to generate, create PDF417 image in Reporting Service applications.
www.OnBarcode.com
Draw European Article Number 13 In Visual Basic .NET
Using Barcode maker for Visual Studio .NET Control to generate, create EAN-13 image in VS .NET applications.
www.OnBarcode.com
18,000,000 43,000 51,000,000 51,000,000 51,000,000
Barcode Recognizer In Visual Studio .NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
PDF 417 Recognizer In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
6,400,000 43,000 9,600,000 9,600,000 9,600,000
Matrix 2D Barcode Generator In Java
Using Barcode drawer for Java Control to generate, create Matrix 2D Barcode image in Java applications.
www.OnBarcode.com
Data Matrix Recognizer In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
c=50
Printing PDF417 In None
Using Barcode encoder for Office Word Control to generate, create PDF417 image in Microsoft Word applications.
www.OnBarcode.com
Reading QR Code ISO/IEC18004 In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
1,600,000 41,000 1,500,000 1,500,000 1,500,000
Reflection.Emit
Lightweight Code Generation
An assembly can t be unloaded from an application domain once it has been loaded. This means the only way to unload an assembly is to unload the entire application domain, which generally means if an assembly needs to be unloaded without terminating a process, a secondary application domain needs to be created just to hold the assemblies that need to be unloaded. In the examples presented in this chapter so far, the dynamically created assemblies are loaded into the main application domain and hence can t be unloaded.
Note For a code example of using a secondary application domain for assembly unloading, see
Maximizing .NET Performance (Apress, 2003) by Nick Wienholt.
In some situations, dynamically generated code is quite small in nature, and the requirement of generating a full assembly and then housing this in a secondary application domain just so it can be unloaded feels like overkill. In recognition of this, .NET 2.0 introduces a lightweight code generation model that allows the generation of static methods without a full assembly, without the requirement to undergo verification (security permissions permissible), and with the ability to be reclaimed without unloading an application domain. Because the methods generated by lightweight code generation must be static, they couldn t be used to implement the polynomial examples presented earlier in this chapter that relied on deriving from the abstract Polynomial class; however, by removing the polymorphic and instance calls, it s possible to solve polynomials with lightweight code generation:
CHAPTER 32 EXECUTION-TIME CODE GENERATION
using System; using System.Reflection; using System.Reflection.Emit; namespace Polynomial { class LightWeightPoly { public void Eval() { // Evaluate the first polynomial, with 7 elements double[] coeff = new double[] { 5.5, 7.0, 15, 30, 500, 100, 1 }; DynamicMethod dm = GetEvaluator(coeff); object[] parameter = new object[] { 2.0 }; double result = (double)dm.Invoke(null, parameter); } DynamicMethod GetEvaluator(params double[] coefficients) { //define dynamic method contruction data Type[] paramTypes = new Type[] { typeof(double) }; Type returnType = typeof(double); Type methodOwner = this.GetType(); // //create dynamic method DynamicMethod dm = new DynamicMethod("Evaluate", returnType, paramTypes, methodOwner, false); ILGenerator il = dm.GetILGenerator(); // // Emit the IL. This is a hand-coded version of what // you'd get if you compiled the code example and then ran // ILDASM on the output. // // // This first section repeated loads the coefficient's // x value on the stack for evaluation. // for (int index = 0; index < coefficients.Length - 1; index++) { il.Emit(OpCodes.Ldc_R8, coefficients[index]); il.Emit(OpCodes.Ldarg_1); } // load the last coefficient il.Emit(OpCodes.Ldc_R8, coefficients[coefficients.Length - 1]); // Emit the remainder of the code. This is a repeated // section of multiplying the terms together and
Copyright © OnBarcode.com . All rights reserved.