Behavior for chunk grid implementations in Zarr v3.

Chunk grids define how arrays are partitioned into chunks. The Zarr v3 specification supports multiple chunk grid types:

• Regular: All chunks have the same shape (except edge chunks)
• Irregular: Chunks can have variable sizes
• Custom: User-defined chunk grid patterns via extensions

Behavior Callbacks

Implementations must provide:

• init/1 - Initialize chunk grid state from configuration
• chunk_shape/2 - Get shape of a specific chunk by index
• chunk_count/1 - Calculate total number of chunks
• validate/2 - Validate chunk grid configuration against array shape

Example

defmodule MyChunkGrid do
  @behaviour ExZarr.ChunkGrid

  defstruct [:chunk_size]

  @impl true
  def init(config) do
    {:ok, %__MODULE__{chunk_size: config["chunk_size"]}}
  end

  @impl true
  def chunk_shape(_chunk_index, state) do
    {state.chunk_size, state.chunk_size}
  end

  @impl true
  def chunk_count(state) do
    # Calculate based on array shape
    100
  end

  @impl true
  def validate(config, array_shape) do
    # Validate configuration
    :ok
  end
end

Specification

Zarr v3 Chunk Grids: https://zarr-specs.readthedocs.io/en/latest/v3/core/index.html#chunk-grids