/*!
 * Copyright (c) Microsoft Corporation and contributors. All rights reserved.
 * Licensed under the MIT License.
 */
import type { ITelemetryBaseLogger } from "@fluidframework/core-interfaces";
import type { ISequencedDocumentMessage } from "@fluidframework/driver-definitions/internal";
/**
 * State machine that "unrolls" contents of compressed batches of ops after decompressing them.
 * This class relies on some implicit contracts defined below:
 * 1. A compressed batch will have its first message with batch metadata set to true and compressed set to true
 * 2. Messages in the middle of a compressed batch will have neither batch metadata nor the compression property set
 * 3. The final message of a batch will have batch metadata set to false
 * 4. An individually compressed op will have undefined batch metadata and compression set to true
 *
 * Compressed batches from current code are always a single message but this class needs to handle a legacy compressed batch with multiple messages
 * because we need that functionality for back compat.
 */
export declare class OpDecompressor {
    private activeBatch;
    private rootMessageContents;
    private processedCount;
    private readonly logger;
    constructor(logger: ITelemetryBaseLogger);
    isCompressedMessage(message: ISequencedDocumentMessage): boolean;
    get currentlyUnrolling(): boolean;
    /**
     * Is the decompressed and stored batch only comprised of a single message
     */
    private isSingleMessageBatch;
    /**
     * Decompress the given compressed message and store it to be subsequently unrolled.
     * The stored message will be of type `any[]` where each element represents a message's `contents`
     */
    decompressAndStore(message: ISequencedDocumentMessage): void;
    /**
     * Unroll the next message from the decompressed content provided to {@link decompressAndStore}
     * @returns the unrolled `ISequencedDocumentMessage`
     */
    unroll(message: ISequencedDocumentMessage): ISequencedDocumentMessage;
}
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