org.apache.commons.compress.archivers.cpio
Class CpioArchiveInputStream

java.lang.Object
  java.io.InputStream
      org.apache.commons.compress.archivers.ArchiveInputStream
          org.apache.commons.compress.archivers.cpio.CpioArchiveInputStream

All Implemented Interfaces:

Closeable, 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(
         new FileInputStream(new File("test.cpio")));
 CPIOArchiveEntry cpioEntry;
 

 while ((cpioEntry = cpioIn.getNextEntry()) != null) {
     System.out.println(cpioEntry.getName());
     int tmp;
     StringBuffer buf = new StringBuffer();
     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)

CpioArchiveInputStream

public CpioArchiveInputStream(InputStream in)

Construct the cpio input stream with a blocksize of BLOCK_SIZE.

Parameters:

in - The cpio stream

CpioArchiveInputStream

public CpioArchiveInputStream(InputStream in,
                              int blockSize)

Construct the cpio input stream with a blocksize of BLOCK_SIZE. Construct the cpio input stream.

Parameters:

in - The cpio stream

blockSize - The block size of the archive.

Since:

1.5

available

public int available()
              throws 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 InputStream

Returns:

1 before EOF and 0 after EOF has reached for current entry.

Throws:

IOException - if an I/O error has occurred or if a CPIO file error has occurred

close

public void close()
           throws IOException

Closes the CPIO input stream.

Specified by:

close in interface Closeable

Overrides:

close in class InputStream

Throws:

IOException - if an I/O error has occurred

getNextCPIOEntry

public CpioArchiveEntry getNextCPIOEntry()
                                  throws IOException

Reads the next CPIO file entry and positions stream at the beginning of the entry data.

Returns:

the CPIOArchiveEntry just read

Throws:

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 IOException

Reads from the current CPIO entry into an array of bytes. Blocks until some input is available.

Overrides:

read in class 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:

IOException - if an I/O error has occurred or if a CPIO file error has occurred

skip

public long skip(long n)
          throws IOException

Skips specified number of bytes in the current CPIO entry.

Overrides:

skip in class InputStream

Parameters:

n - the number of bytes to skip

Returns:

the actual number of bytes skipped

Throws:

IOException - if an I/O error has occurred

IllegalArgumentException - if n < 0

getNextEntry

public ArchiveEntry getNextEntry()
                          throws IOException

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:

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