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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.compress;
import java.util.Arrays;
/**
* Frame based Zstd compressor (https://github.com/facebook/zstd)
* Implemented based on https://github.com/airlift/aircompressor - a pure Java implementation (no JNI).
*
* @author bjorncs
*/
public class ZstdCompressor {
private static final ai.vespa.airlift.zstd.ZstdCompressor compressor = new ai.vespa.airlift.zstd.ZstdCompressor();
private static final ai.vespa.airlift.zstd.ZstdDecompressor decompressor = new ai.vespa.airlift.zstd.ZstdDecompressor();
public byte[] compress(byte[] input, int inputOffset, int inputLength) {
int maxCompressedLength = getMaxCompressedLength(inputLength);
byte[] output = new byte[maxCompressedLength];
int compressedLength = compress(input, inputOffset, inputLength, output, 0, maxCompressedLength);
return Arrays.copyOf(output, compressedLength);
}
public int compress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset, int maxOutputLength) {
return compressor.compress(input, inputOffset, inputLength, output, outputOffset, maxOutputLength);
}
/**
* Note:
* Implementation assumes single frame (since {@link #getDecompressedLength(byte[], int, int)} only includes the first frame)
* The {@link #decompress(byte[], int, int, byte[], int, int)} overload will try to decompress all frames, causing the output buffer to overflow.
*/
public byte[] decompress(byte[] input, int inputOffset, int inputLength) {
int decompressedLength = getDecompressedLength(input, inputOffset, inputLength);
byte[] output = new byte[decompressedLength];
decompress(input, inputOffset, inputLength, output, 0, decompressedLength);
return output;
}
public int decompress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset, int maxOutputLength) {
return decompressor.decompress(input, inputOffset, inputLength, output, outputOffset, maxOutputLength);
}
public static int getMaxCompressedLength(int uncompressedLength) {
return compressor.maxCompressedLength(uncompressedLength);
}
public static int getDecompressedLength(byte[] input, int inputOffset, int inputLength) {
return (int) ai.vespa.airlift.zstd.ZstdDecompressor.getDecompressedSize(input, inputOffset, inputLength);
}
}
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