Class BaseNCodec

java.lang.Object
org.apache.tomcat.util.codec.binary.BaseNCodec
All Implemented Interfaces:
BinaryDecoder, BinaryEncoder, Decoder, Encoder
Direct Known Subclasses:
Base64

public abstract class BaseNCodec extends Object implements BinaryEncoder, BinaryDecoder
Abstract superclass for Base-N encoders and decoders.

This class is thread-safe.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected final int
    Chunksize for encoding.
    protected static final int
    Mask used to extract 8 bits, used in decoding bytes
    static final int
    MIME chunk size per RFC 2045 section 6.8.
    protected final byte
    Pad byte.
    protected static final byte
    Byte used to pad output.
    static final int
    PEM chunk size per RFC 1421 section 4.3.2.4.
    protected static final StringManager
     
  • 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 the encoded block size.
    protected
    BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength, byte pad)
    Note lineLength is rounded down to the nearest multiple of the encoded block size.
  • Method Summary

    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(byte[] pArray, int off, int len)
     
    Deprecated.
    This unused method will be removed in Tomcat 9
    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.
    byte[]
    encode(byte[] pArray, int offset, int length)
    Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
    Deprecated.
    This unused method will be removed in Tomcat 9
    encodeAsString(byte[] pArray)
    Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet.
    encodeToString(byte[] pArray)
    Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet.
    protected byte[]
    ensureBufferSize(int size, org.apache.tomcat.util.codec.binary.BaseNCodec.Context context)
    Ensure that the buffer has room for size bytes
    static byte[]
    Gets a copy of the chunk separator per RFC 2045 section 2.1.
    protected int
    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
    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.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • sm

      protected static final StringManager sm
    • 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:
    • 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:
    • MASK_8BITS

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

      protected static final byte PAD_DEFAULT
      Byte used to pad output.
      See Also:
    • pad

      protected final byte pad
      Pad byte. Instance variable just in case it needs to vary later.
    • 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 the nearest multiple of encodedBlockSize.
  • Constructor Details

    • BaseNCodec

      protected BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength)
      Note lineLength is rounded down to the nearest multiple of the encoded block size. 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
    • BaseNCodec

      protected BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength, byte pad)
      Note lineLength is rounded down to the nearest multiple of the encoded block size. 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
      pad - byte used as padding byte.
  • Method Details

    • getChunkSeparator

      public static byte[] getChunkSeparator()
      Gets a copy of the chunk separator per RFC 2045 section 2.1.
      Returns:
      the chunk separator
      Since:
      1.15
      See Also:
    • 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
    • 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
    • decode

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

      public byte[] decode(byte[] pArray, int off, int len)
    • 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

      @Deprecated public Object decode(Object obj) throws DecoderException
      Deprecated.
      This unused method will be removed in Tomcat 9
      Decodes an Object using the Base-N algorithm. This method is provided in order to satisfy the requirements of the Decoder interface, and will throw a DecoderException if the supplied object is not of type byte[] or String.
      Specified by:
      decode in interface Decoder
      Parameters:
      obj - Object to decode
      Returns:
      An object (of type byte[]) containing the binary data which corresponds to the byte[] or String supplied.
      Throws:
      DecoderException - if the parameter supplied is not of type byte[]
    • encode

      public byte[] encode(byte[] pArray)
      Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
      Specified by:
      encode in interface BinaryEncoder
      Parameters:
      pArray - a byte array containing binary data
      Returns:
      A byte array containing only the base N alphabetic character data
    • encode

      public byte[] encode(byte[] pArray, int offset, int length)
      Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
      Parameters:
      pArray - a byte array containing binary data
      offset - initial offset of the subarray.
      length - length of the subarray.
      Returns:
      A byte array containing only the base N alphabetic character data
      Since:
      1.11
    • 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.
      Since:
      1.5 This is a duplicate of encodeToString(byte[]); it was merged during refactoring.
    • encode

      @Deprecated public Object encode(Object obj) throws EncoderException
      Deprecated.
      This unused method will be removed in Tomcat 9
      Encodes an Object using the Base-N algorithm. This method is provided in order to satisfy the requirements of the Encoder interface, and will throw an EncoderException if the supplied object is not of type byte[].
      Specified by:
      encode in interface Encoder
      Parameters:
      obj - Object to encode
      Returns:
      An object (of type byte[]) containing the Base-N encoded data which corresponds to the byte[] supplied.
      Throws:
      EncoderException - if the parameter supplied is not of type byte[]
    • 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
    • ensureBufferSize

      protected byte[] ensureBufferSize(int size, org.apache.tomcat.util.codec.binary.BaseNCodec.Context context)
      Ensure that the buffer has room for size bytes
      Parameters:
      size - minimum spare space required
      context - the context to be used
      Returns:
      the buffer
    • getDefaultBufferSize

      protected int getDefaultBufferSize()
      Get the default buffer size. Can be overridden.
      Returns:
      the default buffer size.
    • 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 encode the supplied array. Returns a long since a max-len array will require > Integer.MAX_VALUE
    • 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: