Thread: How to decode ENCODING=QUOTED-PRINTABLE encoded data?

Originally Posted by Norm

What format is the source and what format do you want the output in.
The value of '\n' is 0x0A and '\r' is 0x0D

The source is a contact VCARD, and each entry goes on one line if not quoted printable but goes in one or more is used the ENCODING=QUOTED-PRINTABLE string, indicating an ending with the '=' character that continues on the next line:

BEGIN:VCARD
VERSION:2.1
N:Gump;Forrest
FN:Forrest Gump
ORG:Bubba Gump Shrimp Co.
TITLE:Shrimp Man
TEL;WORK;VOICE:(111) 555-1212
TEL;HOME;VOICE:(404) 555-1212
ADR;WORK:;;100 Waters Edge;Baytown;LA;30314;United States of America
LABEL;WORK;ENCODING=QUOTED-PRINTABLE:100 Waters Edge=0D=0ABaytown, LA 30314=0D=0AUnited States of America
ADR;HOME:;;42 Plantation St.;Baytown;LA;30314;United States of America
LABEL;HOME;ENCODING=QUOTED-PRINTABLE:42 Plantation St.=0D=0ABaytown, LA 30314=0D=0AUnited States of America
EMAIL;PREF;INTERNET:forrestgump@example.com
REV:20080424T195243Z
END:VCARD

http://en.wikipedia.org/wiki/VCard

The characters that can be encoded are a lot, not just CRLF, but also {,=, etc.

Sorry I don't understand what the input is that you need to convert.

Can you post some simple examples without all the other stuff?
Show the input String and the output String you want.

It looks like you want to convert the String "=0D" to the String "\r"

Originally Posted by Norm

Sorry I don't understand what the input is that you need to convert.

Can you post some simple examples without all the other stuff?
Show the input String and the output String you want.

It looks like you want to convert the String "=0D" to the String "\r"

Yes, but convert all the cases.

You can check here a webpage that does online conversion, but I would like to do it with software: Encode/Decode Quoted Printable - Webatic

If you change all the = to % there may be an URL decoding class that would convert the hex representation for a character to the character.

Look at the URLDecoder class.

Originally Posted by Norm

If you change all the = to % there may be an URL decoding class that would convert the hex representation for a character to the character.

Look at the URLDecoder class.

It doesn't work if there are some characters (that are not supposed to be in a URL):

Exception in thread "main" java.lang.IllegalArgumentException: URLDecoder: Illegal hex characters in escape (%) pattern - For input string: "*%"
	at java.net.URLDecoder.decode(Unknown Source)
	at java.net.URLDecoder.decode(Unknown Source)

I've solved it using the org.apache.commons.codec package from Apache. The source java files are available for download:
Codec - Home

It contains the method org.apache.commons.codec.net.QuotedPrintableCodec. decodeQuotedPrintable that does the UTF-8 quoted-encoding decodification.

readString is a string read from a file

String decodedString = new String(org.apache.commons.codec.net.QuotedPrintableCodec.decodeQuotedPrintable(readString.getBytes()), "UTF-8");

The readString must contain all the encoded string into a single line, thus if the encoded string is multiline (represented by a '=' at the end of each line), first we must remove each final '=' and append the next string. Then send it to decode.

Of course if the original code is with a different codification from UTF-8 the appropriate must be selected.

The complete UTF-8 character table with its Unicode and Hexadecimal values is shown here:
http://www.utf8-chartable.de/

Also, the output file must be saved in UTF-8 (due to characters in quoted-printable that when decoded can't be represented in ASCII).

So, for input file there must be specified also the input charset.