Java - MemoryLayout

MemoryLayout

The MemoryLayout class lets us describe the contents of a memory segment. Specifically, it lets us define how the memory is broken up into elements, where the size of each element is provided.

This is a bit like describing the memory layout as a concrete type, but without providing a Java class. It's similar to how languages like C++ map their structures to memory.

Let's take an example of a cartesian coordinate point defined with the coordinates x and y:


int numberOfPoints = 10;
MemoryLayout pointLayout = MemoryLayout.ofStruct(
  MemoryLayout.ofValueBits(32, ByteOrder.BIG_ENDIAN).withName("x"),
  MemoryLayout.ofValueBits(32, ByteOrder.BIG_ENDIAN).withName("y")
);
SequenceLayout pointsLayout =
  MemoryLayout.ofSequence(numberOfPoints, pointLayout);

Here, we've defined a layout made of two 32-bit values named x and y. This layout can be used with a SequenceLayout to make something similar to an array, in this case with 10 indices.