package jogampjoclhelloworld;

import com.jogamp.opencl.CLBuffer;
import com.jogamp.opencl.CLCommandQueue;
import com.jogamp.opencl.CLContext;
import com.jogamp.opencl.CLDevice;
import com.jogamp.opencl.CLDevice.Type;
import com.jogamp.opencl.CLEventList;
import com.jogamp.opencl.CLKernel;
import com.jogamp.opencl.CLMemory.Mem;
import com.jogamp.opencl.CLPlatform;
import com.jogamp.opencl.CLProgram;
import java.io.IOException;
import java.nio.ByteBuffer;

public class Main {

    public static void main(String[] args) throws IOException {

        String source = "#pragma OPENCL EXTENSION cl_khr_byte_addressable_store : enable\n__constant uchar hw[] = "
                + "\"Uryyb Jbeyq!\\n\";\n\n__kernel void copyCipher(__global uchar * out) {\n    size_t tid = "
                + "get_global_id(0);\n    out[tid] = hw[tid];\n}\n\n__kernel void decipher(__global uchar * in, "
                + "__global uchar * out) {\n    size_t tid = get_global_id(0);\n\n    uchar letter = in[tid];\n    "
                + "if ((letter <= 'Z') && (letter >= 'A')) {\n        letter += 13;\n        if (letter > 'Z') {\n"
                + "            letter -= 'Z' - 'A' + 1;\n        }\n    } else if ((letter <= 'z') && (letter >= 'a')) "
                + "{\n        letter += 13;\n        if (letter > 'z') {\n            letter -= 'z' - 'a' + 1;\n        "
                + "}\n    }\n\n    out[tid] = letter;\n}";

        byte[] helloWorld = new byte["Hello World!\n".length() + 1];
        ByteBuffer cipherBuffer = ByteBuffer.allocateDirect(helloWorld.length);
        ByteBuffer decodedBuffer = ByteBuffer.allocateDirect(helloWorld.length);

        CLPlatform clPlatform = CLPlatform.getDefault();

        CLContext clContext = CLContext.create(clPlatform, Type.GPU);

        CLBuffer clCipherBuffer = clContext.createBuffer(cipherBuffer, new Mem[]{Mem.READ_WRITE});
        CLBuffer clDecodedBuffer = clContext.createBuffer(decodedBuffer, new Mem[]{Mem.WRITE_ONLY});

        CLDevice clDevice = clContext.getMaxFlopsDevice();

        CLProgram clProgram = clContext.createProgram(source);
        clProgram.build();

        CLKernel clCopyKernel = clProgram.createCLKernel("copyCipher");
        clCopyKernel.setArg(0, clCipherBuffer);
        CLKernel clDecipherKernel = clProgram.createCLKernel("decipher");
        clDecipherKernel.setArg(0, clCipherBuffer);
        clDecipherKernel.setArg(1, clDecodedBuffer);

        CLCommandQueue clCommandQueue = clDevice.createCommandQueue();
        CLEventList eventList = new CLEventList(1);
        clCommandQueue.put1DRangeKernel(clCopyKernel, 0, helloWorld.length, 1, eventList);
        clCommandQueue.put1DRangeKernel(clDecipherKernel, 0, helloWorld.length, 1, eventList, null);
        clCommandQueue.putReadBuffer(clDecodedBuffer, true);

        decodedBuffer.get(helloWorld);

        System.out.println(new String(helloWorld));
    }
}