static String detect()

in src/main/java/org/apache/commons/compress/compressors/CompressorStreamFactory.java [225:275]
51 lines of code
26 McCabe index (conditional complexity)

    static String detect(final InputStream inputStream, final Set<String> compressorNames) throws CompressorException {
        if (inputStream == null) {
            throw new IllegalArgumentException("Stream must not be null.");
        }
        if (compressorNames == null || compressorNames.isEmpty()) {
            throw new IllegalArgumentException("Compressor names cannot be null or empty");
        }
        if (!inputStream.markSupported()) {
            throw new IllegalArgumentException("Mark is not supported.");
        }
        final byte[] signature = new byte[12];
        inputStream.mark(signature.length);
        int signatureLength = -1;
        try {
            signatureLength = IOUtils.readFully(inputStream, signature);
            inputStream.reset();
        } catch (final IOException e) {
            throw new CompressorException("Failed to read signature.", e);
        }
        if (compressorNames.contains(BZIP2) && BZip2CompressorInputStream.matches(signature, signatureLength)) {
            return BZIP2;
        }
        if (compressorNames.contains(GZIP) && GzipCompressorInputStream.matches(signature, signatureLength)) {
            return GZIP;
        }
        if (compressorNames.contains(PACK200) && Pack200CompressorInputStream.matches(signature, signatureLength)) {
            return PACK200;
        }
        if (compressorNames.contains(SNAPPY_FRAMED) && FramedSnappyCompressorInputStream.matches(signature, signatureLength)) {
            return SNAPPY_FRAMED;
        }
        if (compressorNames.contains(Z) && ZCompressorInputStream.matches(signature, signatureLength)) {
            return Z;
        }
        if (compressorNames.contains(DEFLATE) && DeflateCompressorInputStream.matches(signature, signatureLength)) {
            return DEFLATE;
        }
        if (compressorNames.contains(XZ) && XZUtils.matches(signature, signatureLength)) {
            return XZ;
        }
        if (compressorNames.contains(LZMA) && LZMAUtils.matches(signature, signatureLength)) {
            return LZMA;
        }
        if (compressorNames.contains(LZ4_FRAMED) && FramedLZ4CompressorInputStream.matches(signature, signatureLength)) {
            return LZ4_FRAMED;
        }
        if (compressorNames.contains(ZSTANDARD) && ZstdUtils.matches(signature, signatureLength)) {
            return ZSTANDARD;
        }
        throw new CompressorException("No Compressor found for the stream signature.");
    }