JavaCPP Presets for libffi

^{Build status for all platforms: Commercial support:}

Introduction

This directory contains the JavaCPP Presets module for:

• libffi 3.4.2 https://sourceware.org/libffi/

Please refer to the parent README.md file for more detailed information about the JavaCPP Presets.

Documentation

Java API documentation is available here:

• http://bytedeco.org/javacpp-presets/libffi/apidocs/

Sample Usage

Here is a simple example of libffi ported to Java from the "Simple Example" in this file:

• https://github.com/libffi/libffi/blob/master/doc/libffi.texi

We can use Maven 3 to download and install automatically all the class files as well as the native binaries. To run this sample code, after creating the pom.xml and SimpleExample.java source files below, simply execute on the command line:

 $ mvn compile exec:java

The pom.xml build file

<project>
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.bytedeco.libffi</groupId>
    <artifactId>simpleexample</artifactId>
    <version>1.5.6</version>
    <properties>
        <exec.mainClass>SimpleExample</exec.mainClass>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.bytedeco</groupId>
            <artifactId>libffi-platform</artifactId>
            <version>3.4.2-1.5.6</version>
        </dependency>
    </dependencies>
    <build>
        <sourceDirectory>.</sourceDirectory>
    </build>
</project>

The SimpleExample.java source file

import org.bytedeco.javacpp.*;
import org.bytedeco.libffi.*;
import static org.bytedeco.libffi.global.ffi.*;

public class SimpleExample {
     static Pointer puts = Loader.addressof("puts");

     public static void main(String[] a) {
       ffi_cif cif = new ffi_cif();
       PointerPointer<ffi_type> args = new PointerPointer<>(1);
       PointerPointer<PointerPointer> values = new PointerPointer<>(1);
       PointerPointer<BytePointer> s = new PointerPointer<>(1);
       LongPointer rc = new LongPointer(1);

       /* Initialize the argument info vectors */
       args.put(0, ffi_type_pointer());
       values.put(0, s);

       /* Initialize the cif */
       if (ffi_prep_cif(cif, FFI_DEFAULT_ABI(), 1,
                        ffi_type_sint(), args) == FFI_OK)
         {
           s.putString("Hello World!");
           ffi_call(cif, puts, rc, values);
           /* rc now holds the result of the call to puts */

           /* values holds a pointer to the function's arg, so to
              call puts() again all we need to do is change the
              value of s */
           s.putString("This is cool!");
           ffi_call(cif, puts, rc, values);
         }

       System.exit(0);
     }
}