Example usage for org.apache.commons.compress.archivers.dump DumpArchiveInputStream matches

Introduction

In this page you can find the example usage for org.apache.commons.compress.archivers.dump DumpArchiveInputStream matches.

Prototype

public static boolean matches(final byte[] buffer, final int length) 

Source Link

Document

Look at the first few bytes of the file to decide if it's a dump archive.

Usage

From source file:org.apache.tika.parser.pkg.TikaArchiveStreamFactory.java

/**
 * Try to determine the type of Archiver
 * @param in input stream//from ww  w . jav a  2  s .  com
 * @return type of archiver if found
 * @throws ArchiveException if an archiver cannot be detected in the stream
 * @since 1.14
 */
public static String detect(InputStream in) throws ArchiveException {
    if (in == null) {
        throw new IllegalArgumentException("Stream must not be null.");
    }

    if (!in.markSupported()) {
        throw new IllegalArgumentException("Mark is not supported.");
    }

    final byte[] signature = new byte[SIGNATURE_SIZE];
    in.mark(signature.length);
    int signatureLength = -1;
    try {
        signatureLength = IOUtils.readFully(in, signature);
        in.reset();
    } catch (IOException e) {
        throw new ArchiveException("IOException while reading signature.");
    }

    if (ZipArchiveInputStream.matches(signature, signatureLength)) {
        return ZIP;
    } else if (JarArchiveInputStream.matches(signature, signatureLength)) {
        return JAR;
    }
    if (ArArchiveInputStream.matches(signature, signatureLength)) {
        return AR;
    } else if (CpioArchiveInputStream.matches(signature, signatureLength)) {
        return CPIO;
    } else if (ArjArchiveInputStream.matches(signature, signatureLength)) {
        return ARJ;
    } else if (SevenZFile.matches(signature, signatureLength)) {
        return SEVEN_Z;
    }

    // Dump needs a bigger buffer to check the signature;
    final byte[] dumpsig = new byte[DUMP_SIGNATURE_SIZE];
    in.mark(dumpsig.length);
    try {
        signatureLength = IOUtils.readFully(in, dumpsig);
        in.reset();
    } catch (IOException e) {
        throw new ArchiveException("IOException while reading dump signature");
    }
    if (DumpArchiveInputStream.matches(dumpsig, signatureLength)) {
        return DUMP;
    }

    // Tar needs an even bigger buffer to check the signature; read the first block
    final byte[] tarHeader = new byte[TAR_HEADER_SIZE];
    in.mark(tarHeader.length);
    try {
        signatureLength = IOUtils.readFully(in, tarHeader);
        in.reset();
    } catch (IOException e) {
        throw new ArchiveException("IOException while reading tar signature");
    }
    if (TarArchiveInputStream.matches(tarHeader, signatureLength)) {
        return TAR;
    }

    // COMPRESS-117 - improve auto-recognition
    if (signatureLength >= TAR_HEADER_SIZE) {
        TarArchiveInputStream tais = null;
        try {
            tais = new TarArchiveInputStream(new ByteArrayInputStream(tarHeader));
            // COMPRESS-191 - verify the header checksum
            if (tais.getNextTarEntry().isCheckSumOK()) {
                return TAR;
            }
        } catch (final Exception e) { // NOPMD
            // can generate IllegalArgumentException as well
            // as IOException
            // autodetection, simply not a TAR
            // ignored
        } finally {
            IOUtils.closeQuietly(tais);
        }
    }
    throw new ArchiveException("No Archiver found for the stream signature");
}

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