Package org.apache.commons.compress.archivers.cpio

Class CpioArchiveInputStream

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, CpioConstants
    public class CpioArchiveInputStream
extends ArchiveInputStream
implements CpioConstants
    CpioArchiveInputStream is a stream for reading cpio streams. All formats of cpio are supported (old ascii, old binary, new portable format and the new portable format with crc).

    The stream can be read by extracting a cpio entry (containing all informations about a entry) and afterwards reading from the stream the file specified by the entry. 

     CpioArchiveInputStream cpioIn = new CpioArchiveInputStream(
         Files.newInputStream(Paths.get("test.cpio")));
 CpioArchiveEntry cpioEntry;

 while ((cpioEntry = cpioIn.getNextEntry()) != null) {
     System.out.println(cpioEntry.getName());
     int tmp;
     StringBuilder buf = new StringBuilder();
     while ((tmp = cpIn.read()) != -1) {
         buf.append((char) tmp);
     }
     System.out.println(buf.toString());
 }
 cpioIn.close();

    Note: This implementation should be compatible to cpio 2.5

    This class uses mutable fields and is not considered to be threadsafe.

    Based on code from the jRPM project (jrpm.sourceforge.net)

    • Constructor Detail

      • CpioArchiveInputStream

        public CpioArchiveInputStream​(java.io.InputStream in)
        Construct the cpio input stream with a blocksize of BLOCK_SIZE and expecting ASCII file names.
        Parameters:
        in - The cpio stream

      • CpioArchiveInputStream

        public CpioArchiveInputStream​(java.io.InputStream in,
                              java.lang.String encoding)
        Construct the cpio input stream with a blocksize of BLOCK_SIZE.
        Parameters:
        in - The cpio stream
        encoding - The encoding of file names to expect - use null for the platform's default.
        Since:
        1.6

      • CpioArchiveInputStream

        public CpioArchiveInputStream​(java.io.InputStream in,
                              int blockSize)
        Construct the cpio input stream with a blocksize of BLOCK_SIZE expecting ASCII file names.
        Parameters:
        in - The cpio stream
        blockSize - The block size of the archive.
        Since:
        1.5

      • CpioArchiveInputStream

        public CpioArchiveInputStream​(java.io.InputStream in,
                              int blockSize,
                              java.lang.String encoding)
        Construct the cpio input stream with a blocksize of BLOCK_SIZE.
        Parameters:
        in - The cpio stream
        blockSize - The block size of the archive.
        encoding - The encoding of file names to expect - use null for the platform's default.
        Throws:
        java.lang.IllegalArgumentException - if blockSize is not bigger than 0
        Since:
        1.6

    • Method Detail

      • available

        public int available()
              throws java.io.IOException
        Returns 0 after EOF has reached for the current entry data, otherwise always return 1.

        Programs should not count on this method to return the actual number of bytes that could be read without blocking.

        Overrides:
        available in class java.io.InputStream
        Returns:
        1 before EOF and 0 after EOF has reached for current entry.
        Throws:
        java.io.IOException - if an I/O error has occurred or if a CPIO file error has occurred

      • close

        public void close()
           throws java.io.IOException
        Closes the CPIO input stream.
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Overrides:
        close in class java.io.InputStream
        Throws:
        java.io.IOException - if an I/O error has occurred

      • getNextCPIOEntry

        public CpioArchiveEntry getNextCPIOEntry()
                                  throws java.io.IOException
        Reads the next CPIO file entry and positions stream at the beginning of the entry data.
        Returns:
        the CpioArchiveEntry just read
        Throws:
        java.io.IOException - if an I/O error has occurred or if a CPIO file error has occurred

      • read

        public int read​(byte[] b,
                int off,
                int len)
         throws java.io.IOException
        Reads from the current CPIO entry into an array of bytes. Blocks until some input is available.
        Overrides:
        read in class java.io.InputStream
        Parameters:
        b - the buffer into which the data is read
        off - the start offset of the data
        len - the maximum number of bytes read
        Returns:
        the actual number of bytes read, or -1 if the end of the entry is reached
        Throws:
        java.io.IOException - if an I/O error has occurred or if a CPIO file error has occurred

      • skip

        public long skip​(long n)
          throws java.io.IOException
        Skips specified number of bytes in the current CPIO entry.
        Overrides:
        skip in class java.io.InputStream
        Parameters:
        n - the number of bytes to skip
        Returns:
        the actual number of bytes skipped
        Throws:
        java.io.IOException - if an I/O error has occurred
        java.lang.IllegalArgumentException - if n < 0

      • getNextEntry

        public ArchiveEntry getNextEntry()
                          throws java.io.IOException
        Description copied from class: ArchiveInputStream
        Returns the next Archive Entry in this Stream.
        Specified by:
        getNextEntry in class ArchiveInputStream
        Returns:
        the next entry, or null if there are no more entries
        Throws:
        java.io.IOException - if the next entry could not be read

      • matches

        public static boolean matches​(byte[] signature,
                              int length)
        Checks if the signature matches one of the following magic values: Strings: "070701" - MAGIC_NEW "070702" - MAGIC_NEW_CRC "070707" - MAGIC_OLD_ASCII Octal Binary value: 070707 - MAGIC_OLD_BINARY (held as a short) = 0x71C7 or 0xC771
        Parameters:
        signature - data to match
        length - length of data
        Returns:
        whether the buffer seems to contain CPIO data