// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.blobfs.internal;

using zx;

/// Used to transport the Blobfs CompressionAlgorithm enum.
enum CompressionAlgorithm {
    UNCOMPRESSED = 1;
    LZ4 = 2;
    ZSTD = 3;
    ZSTD_SEEKABLE = 4;
    /// For decompressing an entire chunked archive from start to finish.
    CHUNKED = 5;
    /// Used for decompressing only part of a chunked archive.
    CHUNKED_PARTIAL = 6;
};

/// A range of bytes.
struct Range {
    /// Offset in bytes from the start of the VMO.
    uint64 offset;
    /// The number of bytes starting at the offset.
    uint64 size;
};

/// A request sent to the decompressor.
struct DecompressRequest {
    /// The bytes where the decompressed result will be placed.
    Range decompressed;
    /// The bytes from the compressed input to extract from.
    Range compressed;

    /// Algorithm to use for decompression.
    CompressionAlgorithm algorithm;
};

/// A response from the decompressor after handling a `DecompressRangeRequest`.
struct DecompressResponse {
    /// Decompressed size in bytes.
    uint64 size;
    /// Operation status.
    zx.status status;

    /// Padding out to the same length as `DecompressRangeRequest`. Values must be zero.
    array<int8>:24 reserved;
};

[Discoverable]
protocol DecompressorCreator {
    /// Takes the server end of a fifo for `DecompressRangeRequest` objects to
    /// handle requests and put `DecopmressRangeResponse` responses on. Data
    /// for requests is read from `compressed_vmo` and results written to
    /// `decompressed_vmo`.
    Create(zx.handle:FIFO server_end, zx.handle:VMO compressed_vmo,
           zx.handle:VMO decompressed_vmo) -> (zx.status status);
};