Class QuotedPrintableCodec

java.lang.Object
org.apache.commons.codec.net.QuotedPrintableCodec
All Implemented Interfaces:
BinaryDecoder, BinaryEncoder, Decoder, Encoder, StringDecoder, StringEncoder

public class QuotedPrintableCodec extends Object implements BinaryEncoder, BinaryDecoder, StringEncoder, StringDecoder
Codec for the Quoted-Printable section of RFC 1521.

The Quoted-Printable encoding is intended to represent data that largely consists of octets that correspond to printable characters in the ASCII character set. It encodes the data in such a way that the resulting octets are unlikely to be modified by mail transport. If the data being encoded are mostly ASCII text, the encoded form of the data remains largely recognizable by humans. A body which is entirely ASCII may also be encoded in Quoted-Printable to ensure the integrity of the data should the message pass through a character- translating, and/or line-wrapping gateway.

Note:

Depending on the selected strict parameter, this class will implement a different set of rules of the quoted-printable spec:

  • strict=false: only rules #1 and #2 are implemented
  • strict=true: all rules #1 through #5 are implemented

Originally, this class only supported the non-strict mode, but the codec in this partial form could already be used for certain applications that do not require quoted-printable line formatting (rules #3, #4, #5), for instance Q codec. The strict mode has been added in 1.10.

This class is immutable and thread-safe.

Since:
1.3
See Also:
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final Charset
    The default Charset used for string decoding and encoding.
    private static final byte
     
    private static final byte
     
    private static final byte
     
    private static final BitSet
    BitSet of printable characters as defined in RFC 1521.
    private static final int
    Safe line length for quoted printable encoded text.
    private static final byte
     
    private final boolean
    Indicates whether soft line breaks shall be used during encoding (rule #3-5).
    private static final byte
     
  • Constructor Summary

    Constructors
    Constructor
    Description
    Default constructor, assumes default Charset of StandardCharsets.UTF_8
    QuotedPrintableCodec(boolean strict)
    Constructor which allows for the selection of the strict mode.
    Constructor which allows for the selection of a default Charset.
    Constructor which allows for the selection of a default Charset.
    QuotedPrintableCodec(Charset charset, boolean strict)
    Constructor which allows for the selection of a default Charset and strict mode.
  • Method Summary

    Modifier and Type
    Method
    Description
    byte[]
    decode(byte[] bytes)
    Decodes an array of quoted-printable characters into an array of original bytes.
    Decodes a quoted-printable object into its original form.
    decode(String sourceStr)
    Decodes a quoted-printable string into its original form using the default string Charset.
    decode(String sourceStr, String sourceCharset)
    Decodes a quoted-printable string into its original form using the specified string Charset.
    decode(String sourceStr, Charset sourceCharset)
    Decodes a quoted-printable string into its original form using the specified string Charset.
    static final byte[]
    decodeQuotedPrintable(byte[] bytes)
    Decodes an array quoted-printable characters into an array of original bytes.
    byte[]
    encode(byte[] bytes)
    Encodes an array of bytes into an array of quoted-printable 7-bit characters.
    Encodes an object into its quoted-printable safe form.
    encode(String sourceStr)
    Encodes a string into its quoted-printable form using the default string Charset.
    encode(String sourceStr, String sourceCharset)
    Encodes a string into its quoted-printable form using the specified Charset.
    encode(String sourceStr, Charset sourceCharset)
    Encodes a string into its quoted-printable form using the specified Charset.
    private static int
    encodeByte(int b, boolean encode, ByteArrayOutputStream buffer)
    Write a byte to the buffer.
    private static final int
    Encodes byte into its quoted-printable representation.
    static final byte[]
    encodeQuotedPrintable(BitSet printable, byte[] bytes)
    Encodes an array of bytes into an array of quoted-printable 7-bit characters.
    static final byte[]
    encodeQuotedPrintable(BitSet printable, byte[] bytes, boolean strict)
    Encodes an array of bytes into an array of quoted-printable 7-bit characters.
    Gets the default Charset name used for string decoding and encoding.
    Gets the default Charset name used for string decoding and encoding.
    private static int
    getUnsignedOctet(int index, byte[] bytes)
    Return the byte at position index of the byte array and make sure it is unsigned.
    private static boolean
    isWhitespace(int b)
    Checks whether the given byte is whitespace.

    Methods inherited from class java.lang.Object

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

    • charset

      private final Charset charset
      The default Charset used for string decoding and encoding.
    • strict

      private final boolean strict
      Indicates whether soft line breaks shall be used during encoding (rule #3-5).
    • PRINTABLE_CHARS

      private static final BitSet PRINTABLE_CHARS
      BitSet of printable characters as defined in RFC 1521.
    • ESCAPE_CHAR

      private static final byte ESCAPE_CHAR
      See Also:
    • TAB

      private static final byte TAB
      See Also:
    • SPACE

      private static final byte SPACE
      See Also:
    • CR

      private static final byte CR
      See Also:
    • LF

      private static final byte LF
      See Also:
    • SAFE_LENGTH

      private static final int SAFE_LENGTH
      Safe line length for quoted printable encoded text.
      See Also:
  • Constructor Details

    • QuotedPrintableCodec

      public QuotedPrintableCodec()
      Default constructor, assumes default Charset of StandardCharsets.UTF_8
    • QuotedPrintableCodec

      public QuotedPrintableCodec(boolean strict)
      Constructor which allows for the selection of the strict mode.
      Parameters:
      strict - if true, soft line breaks will be used
      Since:
      1.10
    • QuotedPrintableCodec

      public QuotedPrintableCodec(Charset charset)
      Constructor which allows for the selection of a default Charset.
      Parameters:
      charset - the default string Charset to use.
      Since:
      1.7
    • QuotedPrintableCodec

      public QuotedPrintableCodec(Charset charset, boolean strict)
      Constructor which allows for the selection of a default Charset and strict mode.
      Parameters:
      charset - the default string Charset to use.
      strict - if true, soft line breaks will be used
      Since:
      1.10
    • QuotedPrintableCodec

      Constructor which allows for the selection of a default Charset.
      Parameters:
      charsetName - the default string Charset to use.
      Throws:
      UnsupportedCharsetException - If no support for the named Charset is available in this instance of the Java virtual machine
      IllegalArgumentException - If the given charsetName is null
      IllegalCharsetNameException - If the given Charset name is illegal
      Since:
      1.7 throws UnsupportedCharsetException if the named Charset is unavailable
  • Method Details

    • encodeQuotedPrintable

      private static final int encodeQuotedPrintable(int b, ByteArrayOutputStream buffer)
      Encodes byte into its quoted-printable representation.
      Parameters:
      b - byte to encode
      buffer - the buffer to write to
      Returns:
      The number of bytes written to the buffer
    • getUnsignedOctet

      private static int getUnsignedOctet(int index, byte[] bytes)
      Return the byte at position index of the byte array and make sure it is unsigned.
      Parameters:
      index - position in the array
      bytes - the byte array
      Returns:
      the unsigned octet at position index from the array
    • encodeByte

      private static int encodeByte(int b, boolean encode, ByteArrayOutputStream buffer)
      Write a byte to the buffer.
      Parameters:
      b - byte to write
      encode - indicates whether the octet shall be encoded
      buffer - the buffer to write to
      Returns:
      the number of bytes that have been written to the buffer
    • isWhitespace

      private static boolean isWhitespace(int b)
      Checks whether the given byte is whitespace.
      Parameters:
      b - byte to be checked
      Returns:
      true if the byte is either a space or tab character
    • encodeQuotedPrintable

      public static final byte[] encodeQuotedPrintable(BitSet printable, byte[] bytes)
      Encodes an array of bytes into an array of quoted-printable 7-bit characters. Unsafe characters are escaped.

      This function implements a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in RFC 1521 and is suitable for encoding binary data and unformatted text.

      Parameters:
      printable - bitset of characters deemed quoted-printable
      bytes - array of bytes to be encoded
      Returns:
      array of bytes containing quoted-printable data
    • encodeQuotedPrintable

      public static final byte[] encodeQuotedPrintable(BitSet printable, byte[] bytes, boolean strict)
      Encodes an array of bytes into an array of quoted-printable 7-bit characters. Unsafe characters are escaped.

      Depending on the selection of the strict parameter, this function either implements the full ruleset or only a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in RFC 1521 and is suitable for encoding binary data and unformatted text.

      Parameters:
      printable - bitset of characters deemed quoted-printable
      bytes - array of bytes to be encoded
      strict - if true the full ruleset is used, otherwise only rule #1 and rule #2
      Returns:
      array of bytes containing quoted-printable data
      Since:
      1.10
    • decodeQuotedPrintable

      public static final byte[] decodeQuotedPrintable(byte[] bytes) throws DecoderException
      Decodes an array quoted-printable characters into an array of original bytes. Escaped characters are converted back to their original representation.

      This function fully implements the quoted-printable encoding specification (rule #1 through rule #5) as defined in RFC 1521.

      Parameters:
      bytes - array of quoted-printable characters
      Returns:
      array of original bytes
      Throws:
      DecoderException - Thrown if quoted-printable decoding is unsuccessful
    • encode

      public byte[] encode(byte[] bytes)
      Encodes an array of bytes into an array of quoted-printable 7-bit characters. Unsafe characters are escaped.

      Depending on the selection of the strict parameter, this function either implements the full ruleset or only a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in RFC 1521 and is suitable for encoding binary data and unformatted text.

      Specified by:
      encode in interface BinaryEncoder
      Parameters:
      bytes - array of bytes to be encoded
      Returns:
      array of bytes containing quoted-printable data
    • decode

      public byte[] decode(byte[] bytes) throws DecoderException
      Decodes an array of quoted-printable characters into an array of original bytes. Escaped characters are converted back to their original representation.

      This function fully implements the quoted-printable encoding specification (rule #1 through rule #5) as defined in RFC 1521.

      Specified by:
      decode in interface BinaryDecoder
      Parameters:
      bytes - array of quoted-printable characters
      Returns:
      array of original bytes
      Throws:
      DecoderException - Thrown if quoted-printable decoding is unsuccessful
    • encode

      public String encode(String sourceStr) throws EncoderException
      Encodes a string into its quoted-printable form using the default string Charset. Unsafe characters are escaped.

      Depending on the selection of the strict parameter, this function either implements the full ruleset or only a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in RFC 1521 and is suitable for encoding binary data and unformatted text.

      Specified by:
      encode in interface StringEncoder
      Parameters:
      sourceStr - string to convert to quoted-printable form
      Returns:
      quoted-printable string
      Throws:
      EncoderException - Thrown if quoted-printable encoding is unsuccessful
      See Also:
    • decode

      public String decode(String sourceStr, Charset sourceCharset) throws DecoderException
      Decodes a quoted-printable string into its original form using the specified string Charset. Escaped characters are converted back to their original representation.
      Parameters:
      sourceStr - quoted-printable string to convert into its original form
      sourceCharset - the original string Charset
      Returns:
      original string
      Throws:
      DecoderException - Thrown if quoted-printable decoding is unsuccessful
      Since:
      1.7
    • decode

      public String decode(String sourceStr, String sourceCharset) throws DecoderException, UnsupportedEncodingException
      Decodes a quoted-printable string into its original form using the specified string Charset. Escaped characters are converted back to their original representation.
      Parameters:
      sourceStr - quoted-printable string to convert into its original form
      sourceCharset - the original string Charset
      Returns:
      original string
      Throws:
      DecoderException - Thrown if quoted-printable decoding is unsuccessful
      UnsupportedEncodingException - Thrown if Charset is not supported
    • decode

      public String decode(String sourceStr) throws DecoderException
      Decodes a quoted-printable string into its original form using the default string Charset. Escaped characters are converted back to their original representation.
      Specified by:
      decode in interface StringDecoder
      Parameters:
      sourceStr - quoted-printable string to convert into its original form
      Returns:
      original string
      Throws:
      DecoderException - Thrown if quoted-printable decoding is unsuccessful. Thrown if Charset is not supported.
      See Also:
    • encode

      public Object encode(Object obj) throws EncoderException
      Encodes an object into its quoted-printable safe form. Unsafe characters are escaped.
      Specified by:
      encode in interface Encoder
      Parameters:
      obj - string to convert to a quoted-printable form
      Returns:
      quoted-printable object
      Throws:
      EncoderException - Thrown if quoted-printable encoding is not applicable to objects of this type or if encoding is unsuccessful
    • decode

      public Object decode(Object obj) throws DecoderException
      Decodes a quoted-printable object into its original form. Escaped characters are converted back to their original representation.
      Specified by:
      decode in interface Decoder
      Parameters:
      obj - quoted-printable object to convert into its original form
      Returns:
      original object
      Throws:
      DecoderException - Thrown if the argument is not a String or byte[]. Thrown if a failure condition is encountered during the decode process.
    • getCharset

      public Charset getCharset()
      Gets the default Charset name used for string decoding and encoding.
      Returns:
      the default Charset name
      Since:
      1.7
    • getDefaultCharset

      public String getDefaultCharset()
      Gets the default Charset name used for string decoding and encoding.
      Returns:
      the default Charset name
    • encode

      public String encode(String sourceStr, Charset sourceCharset)
      Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.

      Depending on the selection of the strict parameter, this function either implements the full ruleset or only a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in RFC 1521 and is suitable for encoding binary data and unformatted text.

      Parameters:
      sourceStr - string to convert to quoted-printable form
      sourceCharset - the Charset for sourceStr
      Returns:
      quoted-printable string
      Since:
      1.7
    • encode

      public String encode(String sourceStr, String sourceCharset) throws UnsupportedEncodingException
      Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.

      Depending on the selection of the strict parameter, this function either implements the full ruleset or only a subset of quoted-printable encoding specification (rule #1 and rule #2) as defined in RFC 1521 and is suitable for encoding binary data and unformatted text.

      Parameters:
      sourceStr - string to convert to quoted-printable form
      sourceCharset - the Charset for sourceStr
      Returns:
      quoted-printable string
      Throws:
      UnsupportedEncodingException - Thrown if the Charset is not supported