com.github.luben.zstd.ZstdDictDecompress Maven / Gradle / Ivy

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package com.github.luben.zstd;

import com.github.luben.zstd.util.Native;

import java.io.Closeable;
import java.io.IOException;
import java.util.Arrays;

public class ZstdDictDecompress implements Closeable {

    static {
        Native.load();
    }

    private long nativePtr = 0;

    /**
     * Convenience constructor to create a new dictionary for use with fast decompress
     *
     * @param dict buffer containing dictionary to load/parse with exact length
     */
    public ZstdDictDecompress(byte[] dict) {
        this(dict, 0, dict.length);
    }

    /**
     * Create a new dictionary for use with fast decompress
     *
     * @param dict   buffer containing dictionary
     * @param offset the offset into the buffer to read from
     * @param length number of bytes to use from the buffer
     */
    public ZstdDictDecompress(byte[] dict, int offset, int length) {
        byte[] _dict;
        if (0 == offset && length == dict.length) {
            _dict = dict;
        } else {
            _dict = Arrays.copyOfRange(dict, offset, offset + length);
        }

        if (_dict.length <= 0) {
            throw new IllegalArgumentException("Dictionary buffer is to short");
        }

        init(_dict);

        if (0 == nativePtr) {
            throw new IllegalStateException("ZSTD_createCDict failed");
        }
    }

    private native void init(byte[] dict);

    private native void free();

    @Override
    public void close() throws IOException {
        free();
        nativePtr = 0;
    }
}