Crate apr_format 

apr-format — sovereign .apr model container format

Minimal, dependency-light read/write for the .apr model container (v1 APRN + v2 APR\0), extracted from aprender-core so that downstream consumers (realizar inference, xpile, external tooling) can read and write .apr files without pulling the full ML/GPU/tokenizer/quantization stack. See issue #2231 — “depend on the format, not the framework.”

Status: Stage 1 foundation + cut-feasibility spike

This crate currently ships:

• The sovereign error seam (error::AprFormatError, wrapped by aprender-core via impl From).
• The single deduplicated crc32::crc32 and [f16] conversions.
• A representative v1 (APRN) slice — types (header/metadata/flags) and core_io (save/load) — proving the error-seam compiles at a crate boundary.
• The byte-only structural validator split (validate), demonstrating the Structure-vs-Physics separation.

The bulk git-mv of the rest of format/ (v2 container, mmap, spec, …) lands in Stage 2.

Locked design decisions (issue #2231)

1. The GGUF/SafeTensors/ONNX converter stays in aprender-core (it needs f32 physics + the ML stack); only the container moves.
2. std-only for v1 (no no_std yet — the std surface is kept thin).
3. Wrapper error seam: the leaf owns AprFormatError; core From-wraps it.
4. mmap is feature-gated (mmap feature, off by default).

Re-exports

pub use core_io::inspect;

pub use core_io::inspect_bytes;

pub use core_io::load;

pub use core_io::load_auto;

pub use core_io::load_from_bytes;

pub use core_io::load_mmap;

pub use core_io::save;

pub use core_io::MMAP_THRESHOLD;

pub use crc32::crc32;

pub use error::AprFormatError;

pub use error::Result;

pub use f16::f16_to_f32;

pub use f16::f32_to_f16;

pub use model_card::ModelCard;

pub use model_card::TrainingDataInfo;

pub use types::Compression;

pub use types::DistillMethod;

pub use types::DistillationInfo;

pub use types::DistillationParams;

pub use types::Flags;

pub use types::Header;

pub use types::LayerMapping;

pub use types::LicenseInfo;

pub use types::LicenseTier;

pub use types::Metadata;

pub use types::ModelInfo;

pub use types::ModelType;

pub use types::SaveOptions;

pub use types::TeacherProvenance;

pub use types::TrainingInfo;

pub use types::FORMAT_VERSION;

pub use types::HEADER_SIZE;

pub use types::MAGIC;

pub use types::MAX_UNCOMPRESSED_SIZE;

pub use validate::validate_structure;

pub use validate::StructureCheck;

Modules

core_io

v1 (APRN) core I/O — spike slice for issue #2231 Stage 1.

crc32

Single, deduplicated CRC32 implementation for the .apr container.

error

Error type for the sovereign apr-format leaf crate.

f16

IEEE-754 half-precision (f16) conversion, delegating to the half crate.

falsifiers

GREEN contract falsifiers for the apr-format extraction (issue #2231).

model_card

Model Card for .apr format (spec §11)

types

v1 (APRN) container type definitions — sovereign leaf (issue #2231).

v2

APR Format Module (v2 APR\0) — sovereign leaf (issue #2231)

validate

Structural validation — the Structure-category half of the validator split (issue #2231 Stage 1 spike, part b).