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// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: Copyright the Vortex contributors
//! Encoding-agnostic compression framework for Vortex arrays.
//!
//! This crate provides the core compression engine: the [`Scheme`](scheme::Scheme) trait,
//! sampling-based ratio estimation, cascaded compression, and statistics infrastructure for
//! deciding the best encoding scheme for an array.
//!
//! This crate contains no encoding dependencies. Batteries-included compressors are provided by
//! downstream crates like `vortex-btrblocks`, which register different encodings to the compressor.
//!
//! # Observability
//!
//! The compressor emits a small set of `tracing` spans and events on a single target so you can
//! see what it's doing without attaching a profiler.
//!
//! For example, set `RUST_LOG=vortex_compressor::encode=debug` to see compression decision spans
//! and exceptional events. The `vortex_compressor::encode` target carries the top-level `compress`
//! span, per-scheme evaluation and winning-compression spans, the `cascade_exhausted` event,
//! `sample.result` events for zero-byte sample outputs, and both `*.compress_failed` events.
//!
//! The winning-compression span carries `scheme_chosen`, `input_nbytes`, `compressed_nbytes`,
//! `estimated_ratio` (absent when the scheme returned `AlwaysUse` or sampled to 0 bytes),
//! `achieved_ratio` (absent when the compressed output is 0 bytes), and `accepted`.
//!
//! Failure events additionally carry `cascade_path` and `cascade_depth`, so nested compression
//! errors can be tied back to the ancestor branch that triggered them.
//!
//! From those fields you can derive per-scheme savings, rejection counts, and estimator accuracy
//! with a short `jq` query.
pub use CascadingCompressor;