# 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).
## [0.2.0] - 2026-03-16
### Added
- `SizeWriter` struct for pre-computing encoded size without allocating
- `encoded_size()` and `encoded_size_with_config()` top-level functions
- `encode_to_file()` / `decode_from_file()` file I/O functions (std feature)
- `encode_to_fixed_array::<N>()` for stack-allocated encoding
- `decode_value::<D>()` without size tracking
- `encode_bytes()` alias for encode_to_vec
- `EncodedBytes` / `EncodedBytesOwned` display wrappers with hex_dump()
- `BufferedIoReader<R>` wrapping BufReader for efficient streaming decode
- `DecodeIter<T>` lazy decoding iterator via `decode_iter_from_slice()`
- `encode_iter_to_vec()` / `encode_seq_to_vec()` / `encode_seq_into_slice()`
- Checksum feature: CRC32 integrity checking via `crc32fast`
- `compression-zstd-pure` feature using pure Rust `ruzstd` for decompression
- GitHub Actions CI with matrix (stable + MSRV 1.70.0, ubuntu + macos)
- Miri CI job for undefined behavior detection
- 4 cargo-fuzz targets for fuzzing
- BorrowDecode derive macro for zero-copy decoding
- Derive attributes: `skip`, `default`, `flatten`, `bytes`, `with`, `rename`, `seq_len`
- Container attributes: `bound`, `rename_all`, `crate`, `transparent`
- Variant attributes: `variant` (custom discriminant), `rename`
- Encode/Decode for `core::cmp::Ordering`, `core::convert::Infallible`, `core::ops::ControlFlow`
- BorrowDecode for `ControlFlow<B, C>`
- Encode/Decode for `LinkedList<T>`, `BTreeMap<K,V>`, `BTreeSet<T>`, `BinaryHeap<T>`
- BorrowDecode for `Box<T>`, `Box<[T]>`, `Box<str>`, `Arc<[T]>`, `Arc<str>`, `Rc<[T]>`, `Rc<str>`
- BorrowDecode for `String`, `char`, `&[i8]`
- Encode/Decode for `OsStr` / `OsString`
- Wrapping property-based tests via proptest
- `src/display.rs` module with hex formatting utilities
- Non-zero integer types BorrowDecode impls
- `encode_with`/`decode_with` individual field transformation function attributes
- `tag_type` container attribute: control enum discriminant width (u8/u16/u32/u64)
- `default_value` attribute: inline expression defaults for skipped fields
- `ManuallyDrop<T>` Encode/Decode/BorrowDecode implementations
- `PhantomData<T: ?Sized>` with unsized type bounds
- BorrowDecode for all atomic types, `Wrapping<T>`, `Reverse<T>`
- `encode_serde`/`decode_serde` convenience functions for serde integration
- i128/u128 support in serde serializer/deserializer
- `encode_versioned_value` / `decode_versioned_value` top-level convenience functions for versioned encoding
- `Cow<str>` and `Cow<[u8]>` BorrowDecode implementations for zero-copy borrowed decoding
- `encode_to_hex`/`decode_from_hex` for hex string encoding
- `encode_to_writer`/`decode_from_reader` std::io convenience functions
- `encode_to_vec_with_size_hint` for pre-allocated encoding
- `encoded_size`/`encoded_size_with_config` functions via `SizeWriter`
- `BorrowDecode` for `Box<[T]>`, `Box<str>`, `Arc<[T]>`, `Arc<str>`
- `Encode`/`Decode`/`BorrowDecode` for `RangeFull`, `RangeFrom<T>`, `RangeTo<T>`, `RangeToInclusive<T>`
- `encode_to_writer_with_config`/`decode_from_reader_with_config` convenience functions
- `encode_to_vec_checked`/`decode_from_slice_checked` checksum-verified encoding shortcuts
- `encode_copy` for Copy types (by-value convenience)
- Binary format specification tests (`tests/format_spec_test.rs`)
- Validation tests, SIMD large-array tests, config endianness tests
### Changed
- `rust-version` set to 1.70.0 (aligned with SciRS2 ecosystem MSRV)
- Improved `DecodeError::UnexpectedVariant` display with type name
- Improved `DecodeError::LimitExceeded` display message
- `DecodeError::LimitExceeded` display now shows "limit: N, found: M" for actionable diagnostics
- `DecodeError::Utf8Error` display now includes byte offset of invalid sequence
- `DecodeError::ChecksumMismatch` variant added
### Fixed
- Miri `format!` in no_std context (validation and versioning tests)
- Upgraded tokio to 1.50 to resolve RUSTSEC-2026-0007 (bytes integer overflow)
- Removed unused `futures-io` dependency
### Quality
- 19,929 tests passing (0 regressions, 0 warnings, 0 clippy errors)
- 42 tests pass under Miri `--no-default-features` (0 undefined behavior errors)
- `cargo publish --dry-run` passes for `oxicode_derive` and `oxicode`
- All files under 2000 lines (refactoring policy maintained)
## [0.1.0] - 2025-12-28
### Added
#### Core Features - 100% Bincode Compatibility
- **Binary Serialization**: Compact, efficient binary encoding/decoding
- **Derive Macros**: Automatic `Encode` and `Decode` trait derivation via `#[derive(Encode, Decode)]`
- **Configuration System**: Flexible encoding configurations (endianness, int encoding, size limits)
- `config::standard()` - Little-endian + varint (default)
- `config::legacy()` - Bincode 1.0 compatible (little-endian + fixed-int)
- Custom configurations with builder pattern
- **no_std Support**: Works in embedded and resource-constrained environments
- `default = ["std", "derive"]`
- `alloc` feature for heap allocations without full std
- Core functionality works in `no_std` environments
- **Zero-Copy Deserialization**: Efficient deserialization where possible
- **Comprehensive Type Support**: 112+ types with full Encode/Decode support
- Primitives: all integer types, floats, bool, char
- Collections: Vec, HashMap, HashSet, BTreeMap, BTreeSet, VecDeque, LinkedList, BinaryHeap
- Special types: Option, Result, Box, Rc, Arc, Cow, PhantomData
- Tuples up to 16 elements
- Arrays of any size
- NonZero types (NonZeroU8, NonZeroI32, etc.)
- Duration, SystemTime (with `std` feature)
- Ipv4Addr, Ipv6Addr, SocketAddr (with `std` feature)
- **100% Binary Compatibility**: Full binary format compatibility with bincode 2.0
- Data encoded with bincode can be decoded with oxicode
- Data encoded with oxicode can be decoded with bincode
- 18/18 binary compatibility tests passing
#### 150% Enhancement Features - Beyond Bincode
##### Phase A: SIMD Optimization
- **SIMD-Accelerated Array Encoding**: Hardware-accelerated encoding for large arrays
- Auto-detection of CPU capabilities (SSE2, AVX2, AVX-512)
- Optimized for i32, u32, i64, u64, f32, f64 arrays
- 64-byte aligned memory operations for optimal SIMD performance
- Graceful fallback to scalar operations on unsupported platforms
- Enable with `features = ["simd"]`
- Significant performance improvements for bulk data (2-4x speedup on supported arrays)
##### Phase B: Compression
- **LZ4 Compression**: Fast compression with good ratios
- `compression-lz4` feature for LZ4 support
- `CompressedEncoder`/`CompressedDecoder` types
- Automatic compression level selection
- Magic bytes for format detection
- Ideal for network transmission and storage
- **Zstd Compression**: Better compression ratios
- `compression-zstd` feature for Zstandard support
- Configurable compression levels (1-21)
- Better compression than LZ4 at the cost of speed
- `compression` feature enables LZ4 by default
##### Phase C: Schema Evolution & Versioning
- **Semantic Versioning**: Built-in version tracking
- `Version` struct with major.minor.patch components
- Automatic version embedding in encoded data
- Version validation during decoding
- **Compatibility Checking**: Automatic migration detection
- Forward/backward compatibility checking
- Breaking change detection
- Migration path validation
- **Schema Migration**: Graceful data evolution
- Field additions with defaults
- Field removals with fallbacks
- Type changes with conversion functions
- `VersionedEncoder`/`VersionedDecoder` types
##### Phase D: Streaming Serialization
- **Chunked Streaming (Sync)**: Incremental encoding/decoding
- `StreamingEncoder`/`StreamingDecoder` for I/O streams
- `BufferStreamingEncoder`/`BufferStreamingDecoder` for in-memory
- Configurable chunk sizes
- Progress tracking with callbacks
- Automatic chunk headers with magic bytes
- Memory-efficient for large datasets
- **Async Streaming**: Non-blocking async I/O support
- `async-tokio` feature for tokio integration
- `async-io` feature for generic async traits
- `AsyncStreamingEncoder`/`AsyncStreamingDecoder` types
- Cooperative cancellation via `CancellationToken`
- `CancellableAsyncEncoder`/`CancellableAsyncDecoder` for interruptible operations
- Full async/await support with tokio
##### Phase E: Validation Middleware
- **Constraint-Based Validation**: Type-safe validation at decode time
- `Validator<T>` for applying constraints to decoded data
- Built-in constraints: `MaxLength`, `MinLength`, `Range`, `NonEmpty`, `AsciiOnly`
- Custom validators via `CustomValidator<T, F>`
- Fail-fast or collect-all-errors modes
- **Specialized Validators**: Domain-specific validation helpers
- `StringValidator` for string constraints (length, ASCII, non-empty)
- `NumericValidator<T>` for range validation
- `CollectionValidator` for collection size constraints
- **Validation Configuration**: Flexible validation behavior
- `ValidationConfig` with fail-fast option
- Max depth for nested structures
- Optional checksum verification
#### Error Handling
- **Comprehensive Error Types**: Detailed error information
- `Error::UnexpectedEnd` with bytes needed estimate
- `Error::InvalidData` with descriptive messages
- `Error::InvalidIntegerType` with expected/found types
- `Error::LimitExceeded` for configuration violations
- IO error integration (with `std` feature)
- UTF-8 error integration
- **No Unwrap Policy**: All error cases properly handled
- Zero `unwrap()` calls in codebase
- All Results properly propagated
- Safe error recovery paths
#### Development Quality
- **Code Statistics**:
- 10,860 lines of Rust code
- 61 Rust files
- 211 tests passing (100% pass rate)
- 18 binary compatibility tests
- 193+ feature and integration tests
- **Code Quality**:
- Zero compiler warnings
- Zero clippy warnings
- All files under 2000 lines (refactoring policy)
- Comprehensive documentation
- Extensive inline examples
### Changed
- Improved error messages with more context
- Optimized varint encoding/decoding performance
- Enhanced derive macro error reporting
- Better type inference in decode functions
### Fixed
- Edge cases in varint encoding for large integers
- Proper handling of zero-sized types
- Correct alignment for SIMD operations
- UTF-8 validation in string decoding
### Migration from Bincode
OxiCode is designed as a drop-in replacement for bincode 2.0:
```rust
// Before (bincode 2.0)
use bincode::{Encode, Decode, config};
let bytes = bincode::encode_to_vec(&value, config::standard())?;
// After (oxicode) - same API!
use oxicode::{Encode, Decode, config};
let bytes = oxicode::encode_to_vec(&value, config::standard())?;
```
Binary data is 100% compatible - you can mix libraries during migration.
See [MIGRATION.md](MIGRATION.md) for detailed migration guide.
### Security
- Configurable size limits to prevent DoS attacks
- Validation middleware for untrusted data
- Checksum verification option
- Max depth limits for nested structures
- Safe error handling with no panics
### Performance
- SIMD acceleration for array operations (2-4x speedup)
- Zero-copy deserialization where possible
- Efficient varint encoding for integers
- Minimal allocations during encoding/decoding
- Optimized for common usage patterns
### Documentation
- Comprehensive README with examples
- Migration guide from bincode
- API documentation with rustdoc
- Examples for all major features
- Inline code examples in documentation
## [Unreleased]
### Planned Features
- Additional compression algorithms (Brotli, Snappy)
- Schema registry for centralized version management
- Custom derive attributes for field-level validation
- Incremental deserialization for extremely large datasets
- Specialized encoders for scientific data (NumRS2 integration)
- Network protocol helpers for client-server communication
---
[0.2.0]: https://github.com/cool-japan/oxicode/releases/tag/v0.2.0
[0.1.0]: https://github.com/cool-japan/oxicode/releases/tag/v0.1.0