com.github.burrunan.s3cache.internal.zip

Interface ZipEncoding

public interface ZipEncoding

An interface for encoders that do a pretty encoding of ZIP filenames.

There are mostly two implementations, one that uses java.nio Charset and one implementation, which copes with simple 8 bit charsets, because java-1.4 did not support Cp437 in java.nio.

The main reason for defining an own encoding layer comes from the problems with String.getBytes, which encodes unknown characters as ASCII quotation marks ('?'). Quotation marks are per definition an invalid filename on some operating systems like Windows, which leads to ignored ZIP entries.

All implementations should implement this interface in a reentrant way.

Method Summary

Modifier and Type	Method and Description
boolean	canEncode(java.lang.String name) Check, whether the given string may be losslessly encoded using this encoding.
java.lang.String	decode(byte[] data)
java.nio.ByteBuffer	encode(java.lang.String name) Encode a filename or a comment to a byte array suitable for storing it to a serialized zip entry.

Method Detail

canEncode

boolean canEncode(java.lang.String name)

Check, whether the given string may be losslessly encoded using this encoding.

Parameters:

name - A filename or ZIP comment.

Returns:

Whether the given name may be encoded with out any losses.

encode

java.nio.ByteBuffer encode(java.lang.String name)
                    throws java.io.IOException

Encode a filename or a comment to a byte array suitable for storing it to a serialized zip entry.

Examples for CP 437 (in pseudo-notation, right hand side is C-style notation):

  encode("€_for_Dollar.txt") = "%U20AC_for_Dollar.txt"
  encode("Ölfässer.txt") = "\231lf\204sser.txt"
 

Parameters:

name - A filename or ZIP comment.

Returns:

A byte buffer with a backing array containing the encoded name. Unmappable characters or malformed character sequences are mapped to a sequence of utf-16 words encoded in the format %Uxxxx. It is assumed, that the byte buffer is positioned at the beginning of the encoded result, the byte buffer has a backing array and the limit of the byte buffer points to the end of the encoded result.

Throws:

java.io.IOException - if something goes wrong

decode

java.lang.String decode(byte[] data)
                 throws java.io.IOException

Parameters:

data - The byte values to decode.

Returns:

The decoded string.

Throws:

java.io.IOException - if something goes wrong