CJKV Information Processing, 2nd Edition

Repairing Damaged or Unreadable CJKV Text

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Quoted-Printable transformation is dened in Ned Freed and Nathaniel Borenstein’s RFC

2045, Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message

Bodies.

*

RFCs 2047, MIME (Multipurpose Internet Mail Extensions) Part ree: Message

Header Extensions for Non-ASCII Text, and 2231, MIME Parameter Value and Encoded

Word Extensions: Character Sets, Languages, and Continuations, should also be consulted.

†

While most Quoted-Printable–transformed data is found in email message bodies, it can

sometimes be found in email message headers, such as in the following one that I received

(the emboldened portions represent the actual data; the rest is part of the transformation

process that is explained in Table 4-90):

Subject: =?Big5?Q?=A6=5E=C2=D0_=3A_Reply_=3A_Tze=2Dloi_Input_Method?=

e following short Perl program converts Quoted-Printable data back into its original

form:

while (defined($line = <STDIN>)) {

$line =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr hex $1/ge;

$line =~ s/=[\n\r]+$//;

print STDOUT $line;

}

is and many more Perl programs are provided in Appendix C to serve as examples from

which you can write your own routines, whether in Perl or your programming language

of choice.

Base64 Transformation

Base64 transformation is more complex than Quoted-Printable in that it involves manip-

ulation of data at the bit level and ...