Release v1.1.0

Changes

Breaking Changes

• BREAKING: read_last() return signature changed from Optional[bytes] to Tuple[Optional[bytes], int]
  • Now returns (data, size) tuple where size indicates the number of slots the item occupies
  • Migration: Change data = q.read_last() to data, size = q.read_last()
  • Provides actual slot size information instead of always returning full element_size

Added

• Modern format support with efficient last_published_ atomic tracking
  • New last_published_ atomic field at offset 16 for O(1) read_last() performance
  • Header magic number 0x534C5131 ('SLQ1') at offset 24 for format detection
  • Init state atomic at offset 48 for CAS-based ownership detection
  • Automatic format detection distinguishes modern vs legacy queues
• CAS-based queue ownership detection matching C++ implementation (queue.h:618-648)
• Helper methods _wait_for_shared_memory_ready() and _detect_format_version()
• Comprehensive test suites:
  • test_read_last.py: 10 tests covering empty queue, single/multiple items, multi-slot publishes, concurrent publishes, reset, shared memory, wraparound, variable sizes
  • test_read_last_interop.py: 5 tests for Python ↔ C++ interoperability
  • test_modern_format.py: 6 tests for format compatibility and memory layout verification
• C++ test program cpp_read_last_tester.cpp for read_last() interoperability testing
• New constants: SIZE_OFFSET, ELEMENT_SIZE_OFFSET, LAST_PUBLISHED_OFFSET, HEADER_MAGIC_OFFSET, HEADER_MAGIC, INIT_STATE_OFFSET, INIT_STATE_*, K_INVALID_INDEX
• Documentation: READ_LAST_INTEROP.md comprehensive interoperability guide

Changed

• Updated shared memory header layout to match C++ slick-queue v1.x:
  • Reserved info: 8 bytes at offset 0-7 (compact from previous 32-byte padded format)
  • Size: 4 bytes at offset 8-11 (moved from offset 32)
  • Element size: 4 bytes at offset 12-15 (moved from offset 36)
  • Last published: 8 bytes at offset 16-23 (NEW)
  • Header magic: 4 bytes at offset 24-27 (NEW)
  • Init state: 4 bytes at offset 48-51 (NEW)
• publish() now updates last_published_ atomic using CAS loop in modern format (queue.h:331-337)
• reset() now resets last_published_ to K_INVALID_INDEX when in modern format
• close() properly releases _atomic_last_published wrapper
• AtomicReservedInfo.RESERVED_INFO_FMT simplified from 32-byte to 8-byte format
• Repository name changed from slick_queue_py to slick-queue-py
• Updated README.md with new read_last() API documentation
• Enhanced CMakeLists.txt with new test targets

Fixed

• read_last() now returns actual slot size instead of always returning full element_size
• Test queue names shortened to comply with macOS 31-character shared memory name limit

Performance

• O(1) read_last() via direct atomic load (improved from reserved_info calculation)
• Reduced header size: 8-byte reserved_info vs 32-byte padded (24 bytes saved)
• Lock-free last_published_ tracking enables efficient concurrent access

Compatibility

• Backward Compatible: Automatically detects and supports legacy queue format
• C++ Interop: Full compatibility with C++ slick-queue modern format
• Python and C++ can share queues created by either language
• All existing tests continue to pass (atomic ops, cursors, local mode, multi-producer, interop)

Release v1.0.1

Changes

Fixed

• Fixed extra / prefix being added to shared memory names on POSIX systems (Linux/macOS)
• Fixed test failures on Linux and macOS platforms

Added

• macOS shared memory name length validation (31 character limit including / prefix)
• C++ extension support for Linux/macOS platforms with automatic fallback to native methods if unavailable
• atomic_store_64 and atomic_cas_64 functions to C++ extension for improved cross-platform consistency

Changed

• Linux/macOS now prioritize C++ extension for atomic operations, falling back to native methods (__sync_val_compare_and_swap or libatomic) if extension is not available
• Improved atomic operation reliability across all platforms
• Enhanced test suite for better cross-platform compatibility