ex_zarr

# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [0.1.0] - 2026-01-23

### Added

#### Core Functionality
- **Complete array slicing implementation** with `get_slice` and `set_slice` functions
- **Chunked storage system** for efficient I/O and memory usage
- **N-dimensional array support** (1D to N-D) with optimized implementations for 1D and 2D
- **10 data types**: int8, int16, int32, int64, uint8, uint16, uint32, uint64, float32, float64
- **Compression support**: zlib (fully working), with graceful fallbacks for zstd and lz4
- **Two storage backends**:
  - Memory storage (using Agent for persistent state)
  - Filesystem storage (Zarr v2 directory structure)

#### Validation and Safety
- **Comprehensive index validation** for all slicing operations
- **Bounds checking** to prevent out-of-bounds access
- **Data size validation** ensuring data matches slice dimensions
- **Type validation** for indices and data
- **Clear error messages** with actionable feedback

#### Interoperability
- **Full Zarr v2 specification compliance**
- **Bidirectional compatibility with zarr-python**
- **14 integration tests** verifying Python ↔ Elixir compatibility
- **All data types work across implementations**
- **Metadata format compatibility**

#### Documentation
- Comprehensive module documentation with examples
- `INTEROPERABILITY.md` guide for multi-language workflows
- Interactive demo script (`examples/python_interop_demo.exs`)
- Integration test documentation (`test/support/README.md`)
- Python helper scripts for testing

#### Testing
- **196 tests** covering all functionality
- **21 property-based tests** using StreamData
- **35 validation tests** for bounds checking and error handling
- **19 slicing tests** for read/write operations
- **14 Python integration tests** for cross-language compatibility
- **100% passing** test suite with zero failures

#### Code Quality
- Passes all Credo checks (strict mode)
- Well-documented functions and modules
- Type specifications for public APIs
- Consistent error handling patterns

### Technical Details

#### Array Operations
- Row-major (C-order) data layout
- Lazy chunk loading (only loads needed chunks)
- Efficient slice extraction across chunk boundaries
- Partial chunk updates (read-modify-write)
- Fill value support for uninitialized regions

#### Performance Optimizations
- Dimension-specific implementations (1D, 2D, ND)
- Minimal data copying during operations
- Efficient binary pattern matching
- Agent-based memory storage for fast writes

#### Metadata
- Zarr v2 JSON metadata format
- Shape, chunks, dtype, compressor configuration
- Fill value preservation
- Automatic metadata generation

### Breaking Changes
None (initial release)

### Deprecated
None

### Fixed
- Memory storage now correctly persists writes using Agent
- Chunk boundary calculations work correctly for all dimensions
- Data size validation accounts for element size
- Index validation prevents invalid operations before I/O

### Security
- Input validation prevents buffer overflows
- Bounds checking prevents out-of-bounds access
- Type checking ensures data integrity

## [Unreleased]

### Planned Features
- Additional compression codecs (native zstd, lz4)
- Zarr v3 support
- S3 storage backend
- Parallel chunk operations
- Advanced indexing (fancy indexing, boolean indexing)
- Numpy-style broadcasting

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[0.1.0]: https://github.com/your-username/ex_zarr/releases/tag/v0.1.0