Module codec 

MNF5 (v0.5 format): atlas codec, zlib container.

Structs

Atlas

Atlas: previously decoded patches, ranked lookup by signature.

DecodeLimits

Configurable decoder resource ceilings (review fix 3). Defaults are the format-derived maxima; callers decoding untrusted input can tighten any of them independently.

DecodeResult

Decoded image: dims + RGB8 pixels.

Dims

Image dimensions in pixels.

GeomStats

Encode statistics (per-tile choices/savings; feeds vis maps).

Sig

Tile signature: RGB means used for nearest-neighbor ranking.

Tile

A tile: raw RGB data plus its (possibly partial) edge dims.

Enums

Mode

Per-tile record kinds: literal or reference (v0.5 mode grammar).

Constants

ATLAS_CAPACITY

Atlas cap: max distinct previously-decoded patches tracked.

HEADER_SIZE

Magic + header size (bytes): MNF5 + 5×u32 LE.

NUM_TRANSFORMS

D8 geometric transforms considered (identity + rotation/reflection).

RANK_CANDIDATES

Best-N references evaluated per tile after signature ranking.

TILE_SIZE

Tile edge in pixels (both axes).

Functions

apply_transform

Pixel bytes after D8 transform t (deterministic integer perm).

build_header

Build the 24-byte MNF5 header.

compress_payload

zlib-compress the assembled record stream (level 9).

decode

Decode an MNF5 file (header + zlib payload) back to RGB8 pixels.

decode_with_limits

Decode MNF5 with configurable ceilings.

div_ceil

Ceiling division.

encode_mnf5

One-call MNF5 encode (the CLI’s pipeline exposed as API): split, encode the tile stream, compress, and assemble header + payload.

encode_stats

Encode + utilization counters (v0.6 exit metric: reference utilization).

encode_tiles

Encode a tile stream (row-major, tile_dims shapes) with optional atlas matching. Raw bytes per tile: mode, optional idx, optional transform, body; mode 2 (geometric atlas, v0.6) writes both index (u32 LE) and transform id (u8) after the mode byte. use_geom extends matching to the D8 group; with use_atlas only, exact prior-patch references (v0.5 behavior) are used.

split_tiles

Split an RGB8 pixel buffer into row-major Tiles (public: CLI uses the same tiling as encoder/decoder/tests — one definition of truth).

tile_dims

(w,h) of tile t, respecting partial edge tiles.

tile_grid

(tiles_per_row, tile_rows) for the row-major tile scan.

tile_proxy_cost

Cost proxy for one tile’s contribution to the compressed stream. ponytail: per-tile zlib call is O(128) small compressions per tile — fine at benchmark scale; if profiling shows it hot, cache or use a rolling window.

tile_sig

Compute a tile’s signature for atlas ranking.

transform_dims

Dims of a tile after D8 transform t (swapped for rotations).

transform_is_valid_for

Which transforms keep the tile shape (a reference must reproduce tw x th): all 8 on square patches, only the identity/hflip/vflip/rot180 subgroup on non-square partial tiles.