Class BaseNCodec

  • Direct Known Subclasses:
    Base64

    public abstract class BaseNCodec
    extends Object

    reference of apache pivot

    Abstract superclass for Base-N encoders and decoders.

    This class is thread-safe.

    Version:
    $Id: BaseNCodec.java 1465182 2013-04-06 04:03:12Z ggregory $
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected int lineLength
      Chunksize for encoding.
      protected static int MASK_8BITS
      Mask used to extract 8 bits, used in decoding bytes
      static int MIME_CHUNK_SIZE
      MIME chunk size per RFC 2045 section 6.8.
      protected byte PAD  
      protected static byte PAD_DEFAULT
      Byte used to pad output.
      static int PEM_CHUNK_SIZE
      PEM chunk size per RFC 1421 section 4.3.2.4.
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected BaseNCodec​(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength)
      Note lineLength is rounded down to the nearest multiple of encodedBlockSize If chunkSeparatorLength is zero, then chunking is disabled.
    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      protected boolean containsAlphabetOrPad​(byte[] arrayOctet)
      Tests a given byte array to see if it contains any characters within the alphabet or PAD.
      byte[] decode​(byte[] pArray)
      Decodes a byte[] containing characters in the Base-N alphabet.
      byte[] decode​(String pArray)
      Decodes a String containing characters in the Base-N alphabet.
      byte[] encode​(byte[] pArray)
      Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
      String encodeAsString​(byte[] pArray)
      Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet.
      String encodeToString​(byte[] pArray)
      Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet.
      protected byte[] ensureBufferSize​(int size, com.zone.weixin4j.base64.BaseNCodec.Context context)
      Ensure that the buffer has room for size bytes
      protected int getDefaultBufferSize()
      Get the default buffer size.
      long getEncodedLength​(byte[] pArray)
      Calculates the amount of space needed to encode the supplied array.
      protected abstract boolean isInAlphabet​(byte value)
      Returns whether or not the octet is in the current alphabet.
      boolean isInAlphabet​(byte[] arrayOctet, boolean allowWSPad)
      Tests a given byte array to see if it contains only valid characters within the alphabet.
      boolean isInAlphabet​(String basen)
      Tests a given String to see if it contains only valid characters within the alphabet.
      protected static boolean isWhiteSpace​(byte byteToCheck)
      Checks if a byte value is whitespace or not.
    • Field Detail

      • MIME_CHUNK_SIZE

        public static final int MIME_CHUNK_SIZE
        MIME chunk size per RFC 2045 section 6.8.

        The 76 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.

        See Also:
        RFC 2045 section 6.8, Constant Field Values
      • PEM_CHUNK_SIZE

        public static final int PEM_CHUNK_SIZE
        PEM chunk size per RFC 1421 section 4.3.2.4.

        The 64 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.

        See Also:
        RFC 1421 section 4.3.2.4, Constant Field Values
      • MASK_8BITS

        protected static final int MASK_8BITS
        Mask used to extract 8 bits, used in decoding bytes
        See Also:
        Constant Field Values
      • PAD_DEFAULT

        protected static final byte PAD_DEFAULT
        Byte used to pad output.
        See Also:
        Constant Field Values
      • lineLength

        protected final int lineLength
        Chunksize for encoding. Not used when decoding. A value of zero or less implies no chunking of the encoded data. Rounded down to nearest multiple of encodedBlockSize.
    • Constructor Detail

      • BaseNCodec

        protected BaseNCodec​(int unencodedBlockSize,
                             int encodedBlockSize,
                             int lineLength,
                             int chunkSeparatorLength)
        Note lineLength is rounded down to the nearest multiple of encodedBlockSize If chunkSeparatorLength is zero, then chunking is disabled.
        Parameters:
        unencodedBlockSize - the size of an unencoded block (e.g. Base64 = 3)
        encodedBlockSize - the size of an encoded block (e.g. Base64 = 4)
        lineLength - if > 0, use chunking with a length lineLength
        chunkSeparatorLength - the chunk separator length, if relevant
    • Method Detail

      • getDefaultBufferSize

        protected int getDefaultBufferSize()
        Get the default buffer size. Can be overridden.
        Returns:
        DEFAULT_BUFFER_SIZE
      • ensureBufferSize

        protected byte[] ensureBufferSize​(int size,
                                          com.zone.weixin4j.base64.BaseNCodec.Context context)
        Ensure that the buffer has room for size bytes
        Parameters:
        size - minimum spare space required
        context - the context to be used
      • isWhiteSpace

        protected static boolean isWhiteSpace​(byte byteToCheck)
        Checks if a byte value is whitespace or not. Whitespace is taken to mean: space, tab, CR, LF
        Parameters:
        byteToCheck - the byte to check
        Returns:
        true if byte is whitespace, false otherwise
      • encodeToString

        public String encodeToString​(byte[] pArray)
        Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet. Uses UTF8 encoding.
        Parameters:
        pArray - a byte array containing binary data
        Returns:
        A String containing only Base-N character data
      • encodeAsString

        public String encodeAsString​(byte[] pArray)
        Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet. Uses UTF8 encoding.
        Parameters:
        pArray - a byte array containing binary data
        Returns:
        String containing only character data in the appropriate alphabet.
      • decode

        public byte[] decode​(String pArray)
        Decodes a String containing characters in the Base-N alphabet.
        Parameters:
        pArray - A String containing Base-N character data
        Returns:
        a byte array containing binary data
      • decode

        public byte[] decode​(byte[] pArray)
        Decodes a byte[] containing characters in the Base-N alphabet.
        Parameters:
        pArray - A byte array containing Base-N character data
        Returns:
        a byte array containing binary data
      • encode

        public byte[] encode​(byte[] pArray)
        Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
        Parameters:
        pArray - a byte array containing binary data
        Returns:
        A byte array containing only the basen alphabetic character data
      • isInAlphabet

        protected abstract boolean isInAlphabet​(byte value)
        Returns whether or not the octet is in the current alphabet. Does not allow whitespace or pad.
        Parameters:
        value - The value to test
        Returns:
        true if the value is defined in the current alphabet, false otherwise.
      • isInAlphabet

        public boolean isInAlphabet​(byte[] arrayOctet,
                                    boolean allowWSPad)
        Tests a given byte array to see if it contains only valid characters within the alphabet. The method optionally treats whitespace and pad as valid.
        Parameters:
        arrayOctet - byte array to test
        allowWSPad - if true, then whitespace and PAD are also allowed
        Returns:
        true if all bytes are valid characters in the alphabet or if the byte array is empty; false, otherwise
      • isInAlphabet

        public boolean isInAlphabet​(String basen)
        Tests a given String to see if it contains only valid characters within the alphabet. The method treats whitespace and PAD as valid.
        Parameters:
        basen - String to test
        Returns:
        true if all characters in the String are valid characters in the alphabet or if the String is empty; false, otherwise
        See Also:
        isInAlphabet(byte[], boolean)
      • containsAlphabetOrPad

        protected boolean containsAlphabetOrPad​(byte[] arrayOctet)
        Tests a given byte array to see if it contains any characters within the alphabet or PAD. Intended for use in checking line-ending arrays
        Parameters:
        arrayOctet - byte array to test
        Returns:
        true if any byte is a valid character in the alphabet or PAD; false otherwise
      • getEncodedLength

        public long getEncodedLength​(byte[] pArray)
        Calculates the amount of space needed to encode the supplied array.
        Parameters:
        pArray - byte[] array which will later be encoded
        Returns:
        amount of space needed to encoded the supplied array. Returns a long since a max-len array will require > Integer.MAX_VALUE