packfs-core/dist/esm/compression/ZstdStrategy.js

Semantic filesystem operations for LLM agent frameworks with natural language understanding. See LLM_AGENT_GUIDE.md for copy-paste examples.

import { CompressionStrategy } from './CompressionStrategy';
import { compress as zstdCompress, decompress as zstdDecompress } from '@mongodb-js/zstd';
/**
 * Zstd compression strategy - provides excellent balance between compression ratio and speed
 */
export class ZstdStrategy extends CompressionStrategy {
    constructor(compressionLevel = 3) {
        super();
        this.name = 'zstd';
        this.priority = 'balanced';
        this.supportsStreaming = true;
        this.compressionLevel = compressionLevel;
    }
    async compress(data, hints) {
        const startTime = performance.now();
        // Use real Zstd compression
        const level = this.getCompressionLevel(hints);
        const compressed = await zstdCompress(data, level);
        const compressionTime = performance.now() - startTime;
        return {
            data: compressed,
            algorithm: this.name,
            originalSize: data.length,
            compressedSize: compressed.length,
            metadata: {
                compressionTime,
                level,
                dictionary: hints.ecosystem ? `${hints.ecosystem}-dict` : undefined
            }
        };
    }
    async decompress(chunk) {
        const startTime = performance.now();
        // Use real Zstd decompression
        const result = await zstdDecompress(chunk.data);
        const decompressionTime = performance.now() - startTime;
        chunk.metadata.decompressionTime = decompressionTime;
        return result;
    }
    createDecompressor(chunk) {
        const { Readable } = require('stream');
        return new Readable({
            async read() {
                try {
                    // Use real Zstd decompression
                    const decompressed = await zstdDecompress(chunk.data);
                    this.push(decompressed);
                    this.push(null);
                }
                catch (error) {
                    this.emit('error', error);
                }
            }
        });
    }
    estimateRatio(_data, hints) {
        if (this.isStructuredData(hints.mimeType)) {
            return 0.2; // 80% compression for JSON, config files
        }
        if (this.isCodeFile(hints.mimeType)) {
            return 0.3; // 70% compression for source code
        }
        return 0.5; // 50% compression for other data
    }
    shouldUse(data, hints) {
        // Excellent for structured data (JSON, YAML, etc.)
        if (this.isStructuredData(hints.mimeType)) {
            return true;
        }
        // Good balance for most use cases
        if (hints.accessFrequency >= 0.3 && hints.accessFrequency < 0.8) {
            return true;
        }
        // Great for medium-sized files
        if (data.length > 10 * 1024 && data.length < 1024 * 1024) {
            return true;
        }
        return false;
    }
    getCompressionLevel(hints) {
        if (hints.isHot) {
            return 1; // Fastest compression
        }
        if (hints.accessFrequency >= 0.5) {
            return 3; // Balanced
        }
        return Math.min(19, this.compressionLevel + 5); // Higher compression for cold data
    }
    isStructuredData(mimeType) {
        return mimeType.includes('json') ||
            mimeType.includes('yaml') ||
            mimeType.includes('toml') ||
            mimeType.includes('xml') ||
            mimeType.endsWith('.config');
    }
    isCodeFile(mimeType) {
        return mimeType.includes('javascript') ||
            mimeType.includes('typescript') ||
            mimeType.includes('python') ||
            mimeType.includes('rust') ||
            mimeType.includes('go');
    }
}
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