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:

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)

Field Summary

Fields inherited from interface org.apache.commons.compress.archivers.cpio.CpioConstants

BLOCK_SIZE, C_IRGRP, C_IROTH, C_IRUSR, C_ISBLK, C_ISCHR, C_ISDIR, C_ISFIFO, C_ISGID, C_ISLNK, C_ISNWK, C_ISREG, C_ISSOCK, C_ISUID, C_ISVTX, C_IWGRP, C_IWOTH, C_IWUSR, C_IXGRP, C_IXOTH, C_IXUSR, CPIO_TRAILER, FORMAT_NEW, FORMAT_NEW_CRC, FORMAT_NEW_MASK, FORMAT_OLD_ASCII, FORMAT_OLD_BINARY, FORMAT_OLD_MASK, MAGIC_NEW, MAGIC_NEW_CRC, MAGIC_OLD_ASCII, MAGIC_OLD_BINARY, S_IFMT

Constructor Summary

Constructors

Constructor and Description
CpioArchiveInputStream(java.io.InputStream in) Construct the cpio input stream with a blocksize of BLOCK_SIZE and expecting ASCII file names.
CpioArchiveInputStream(java.io.InputStream in, int blockSize) Construct the cpio input stream with a blocksize of BLOCK_SIZE expecting ASCII file names.
CpioArchiveInputStream(java.io.InputStream in, int blockSize, java.lang.String encoding) Construct the cpio input stream with a blocksize of BLOCK_SIZE.
CpioArchiveInputStream(java.io.InputStream in, java.lang.String encoding) Construct the cpio input stream with a blocksize of BLOCK_SIZE.

Method Summary

Modifier and Type	Method and Description
int	available() Returns 0 after EOF has reached for the current entry data, otherwise always return 1.
void	close() Closes the CPIO input stream.
CpioArchiveEntry	getNextCPIOEntry() Reads the next CPIO file entry and positions stream at the beginning of the entry data.
ArchiveEntry	getNextEntry() Returns the next Archive Entry in this Stream.
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
int	read(byte[] b, int off, int len) Reads from the current CPIO entry into an array of bytes.
long	skip(long n) Skips specified number of bytes in the current CPIO entry.

Methods inherited from class org.apache.commons.compress.archivers.ArchiveInputStream

canReadEntryData, getBytesRead, getCount, read

Methods inherited from class java.io.InputStream

mark, markSupported, read, reset

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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.

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.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

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