swig: add libwebp.jar/libwebp_java_wrap.c

for the swig-impaired

Change-Id: I10711c057c11bd9e59bc382fe3c6337883f5c4a6

swig/README

@@ -0,0 +1,34 @@
+Building:
+=========
+
+JNI SWIG bindings:
+------------------
+ $ gcc -shared -fPIC -fno-strict-aliasing -O2 \
+       -I/path/to/your/jdk/includes \
+       libwebp_java_wrap.c \
+       -lwebp \
+       -o libwebp_jni.so
+
+-------------------------------------- BEGIN PSEUDO EXAMPLE
+import com.google.webp.*;
+import java.io.*;
+
+public class libwebp_jni_example {
+  static {
+    System.loadLibrary("webp_jni");
+  }
+
+  /**
+   * usage: java -cp libwebp.jar:.
+   *        libwebp_jni_example <input.webp> <output.ppm>
+   */
+  public static void main(String argv[]) {
+    final int version = libwebp.WebPGetDecoderVersion();
+
+    System.out.println("libwebp version: " + Integer.toHexString(version));
+  }
+}
+-------------------------------------- END PSEUDO EXAMPLE
+
+ $ javac -cp libwebp.jar libwebp_jni_example.java
+ $ java -Djava.library.path=. -cp libwebp.jar:. libwebp_jni_example