decoding quoted-printables

Question

I am looking for a way to decode quoted-printables.

The quoted-printables are for arabic characters and look like this:

=D8=B3=D8=B9=D8=A7=D8=AF

I need to convert it to a string, and store it or display..

I've seen post on stackoverflow for the other way around (encoding), but couldn't find decoding.

Answer 1

Uhm, it's a little hacky but you could replace the = characters with a % character and use NSString's stringByReplacingPercentEscapesUsingEncoding: method. Otherwise, you could essentially split the string on the = characters, convert each element to a byte value (easily done using NSScanner), put the byte values into a C array, and use NSString's initWithBytes:length:encoding: method.

Note that your example isn't technically in quoted-printable format, which specifies that a quoted-printable is a three character sequence consisting of an = character followed by two hex digits.

Answer 2

In my case I was coming from EML... bensnider's answer worked great... quoted-printable (at least in EML) uses an = sign followed by \r\n to signify a line wrapping, so this was the code needed to cleanly translate:

(Made as a category cause I loves dem)

@interface NSString (QuotedPrintable)
- (NSString *)quotedPrintableDecode;
@end

@implementation NSString (QuotedPrintable)
- (NSString *)quotedPrintableDecode
{
    NSString *decodedString = [self stringByReplacingOccurrencesOfString:@"=\r\n" withString:@""]; // Ditch the line wrap indicators
    decodedString = [decodedString stringByReplacingOccurrencesOfString:@"=" withString:@"%"]; // Change the ='s to %'s
    decodedString = [decodedString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; // Replace the escaped strings.
    return decodedString;
}
@end

Which worked great for decoding my EML / UTF-8 objects!