package org.cef.misc;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.MethodType;

import java.nio.ByteBuffer;

public class DataPointer {

private final long address;

private ByteBuffer dataBuffer;

boolean initialized = false;

int alignment = 3;

public DataPointer(long address) {

this.address = address;

}

public DataPointer forCapacity(int capacity) {

try {

dataBuffer = (ByteBuffer) memByteBuffer.invoke(address, capacity);

initialized = true;

return this;

} catch (Throwable err) {

throw new RuntimeException("Failed to invoke memByteBuffer?", err);

}

}

public DataPointer withAlignment(int alignment) {

this.alignment = alignment;

return this;

}

public long getAddress() {

return address;

}

public DataPointer getData(int offset) {

if (!initialized) throw new RuntimeException("DataPoint#forCapacity must be called before the data can be accessed.");

return new DataPointer(dataBuffer.getLong(offset << alignment));

}

public long getLong(int offset) {

if (!initialized) throw new RuntimeException("DataPoint#forCapacity must be called before the data can be accessed.");

return dataBuffer.getLong(offset << alignment);

}

public int getInt(int offset) {

if (!initialized) throw new RuntimeException("DataPoint#forCapacity must be called before the data can be accessed.");

return dataBuffer.getInt(offset << alignment);

}

public short getShort(int offset) {

if (!initialized) throw new RuntimeException("DataPoint#forCapacity must be called before the data can be accessed.");

return dataBuffer.getShort(offset << alignment);

}

public byte getByte(int offset) {

if (!initialized) throw new RuntimeException("DataPoint#forCapacity must be called before the data can be accessed.");

return dataBuffer.get(offset << alignment);

}

public double getDouble(int offset) {

if (!initialized) throw new RuntimeException("DataPoint#forCapacity must be called before the data can be accessed.");

return dataBuffer.getDouble(offset << alignment);

}

public float getFloat(int offset) {

if (!initialized) throw new RuntimeException("DataPoint#forCapacity must be called before the data can be accessed.");

return dataBuffer.getFloat(offset << alignment);

}

// TODO: ideally we'd just directly depend on lwjgl, since we require it for GLFW anyway

private static final MethodHandle memByteBuffer;

static {

MethodHandles.Lookup lookup = MethodHandles.lookup();

try {

Class<?> clz = Class.forName("org.lwjgl.system.MemoryUtil", false, lookup.lookupClass().getClassLoader());

memByteBuffer = lookup.findStatic(clz, "memByteBuffer", MethodType.methodType(ByteBuffer.class, new Class[]{Long.TYPE, Integer.TYPE}));

} catch (Throwable err) {

System.err.println("Could not find LWJGL MemoryUtil's memByteBuffer method.\nAre you using LWJGL 3.x?");

throw new RuntimeException(err);

}

}

}