NKF

Inheritance

NKF - Ruby extension for Network Kanji Filter

Description

This is a Ruby Extension version of nkf (Netowrk Kanji Filter). It converts the first argument and return converted result. Conversion details are specified by flags as the first argument.

Nkf is a yet another kanji code converter among networks, hosts and terminals. It converts input kanji code to designated kanji code such as ISO-2022-JP, Shift_JIS, EUC-JP, UTF-8 or UTF-16.

One of the most unique faculty of nkf is the guess of the input kanji encodings. It currently recognizes ISO-2022-JP, Shift_JIS, EUC-JP, UTF-8 and UTF-16. So users needn‘t set the input kanji code explicitly.

By default, X0201 kana is converted into X0208 kana. For X0201 kana, SO/SI, SSO and ESC-(-I methods are supported. For automatic code detection, nkf assumes no X0201 kana in Shift_JIS. To accept X0201 in Shift_JIS, use -X, -x or -S.

Flags

-b -u

Output is buffered (DEFAULT), Output is unbuffered.

-j -s -e -w -w16

Output code is ISO-2022-JP (7bit JIS), Shift_JIS, EUC-JP, UTF-8N, UTF-16BE. Without this option and compile option, ISO-2022-JP is assumed.

-J -S -E -W -W16

Input assumption is JIS 7 bit, Shift_JIS, EUC-JP, UTF-8, UTF-16LE.

-J

Assume JIS input. It also accepts EUC-JP. This is the default. This flag does not exclude Shift_JIS.

-S

Assume Shift_JIS and X0201 kana input. It also accepts JIS. EUC-JP is recognized as X0201 kana. Without -x flag, X0201 kana (halfwidth kana) is converted into X0208.

-E

Assume EUC-JP input. It also accepts JIS. Same as -J.

-t

No conversion.

-i_

Output sequence to designate JIS-kanji. (DEFAULT B)

-o_

Output sequence to designate ASCII. (DEFAULT B)

-r

{de/en}crypt ROT13/47

-h[123] —hiragana —katakana —katakana-hiragana

-h1 —hiragana: Katakana to Hiragana conversion.
-h2 —katakana: Hiragana to Katakana conversion.
-h3 —katakana-hiragana: Katakana to Hiragana and Hiragana to Katakana conversion.

-T

Text mode output (MS-DOS)

-l

ISO8859-1 (Latin-1) support

-f[`m` [- `n`]]

Folding on m length with n margin in a line. Without this option, fold length is 60 and fold margin is 10.

-F

New line preserving line folding.

-Z[0-3]

Convert X0208 alphabet (Fullwidth Alphabets) to ASCII.

-Z -Z0: Convert X0208 alphabet to ASCII.
-Z1: Converts X0208 kankaku to single ASCII space.
-Z2: Converts X0208 kankaku to double ASCII spaces.
-Z3: Replacing Fullwidth >, <, ", & into ’>’, ’<’, ’"’, ’&’ as in HTML.

-X -x

Assume X0201 kana in MS-Kanji. With -X or without this option, X0201 is converted into X0208 Kana. With -x, try to preserve X0208 kana and do not convert X0201 kana to X0208. In JIS output, ESC-(-I is used. In EUC output, SSO is used.

-B[0-2]

Assume broken JIS-Kanji input, which lost ESC. Useful when your site is using old B-News Nihongo patch.

-B1: allows any char after ESC-( or ESC-$.
-B2: forces ASCII after NL.

-I

Replacing non iso-2022-jp char into a geta character (substitute character in Japanese).

-d -c

Delete \r in line feed, Add \r in line feed.

-m[BQN0]

MIME ISO-2022-JP/ISO8859-1 decode. (DEFAULT) To see ISO8859-1 (Latin-1) -l is necessary.

-mB: Decode MIME base64 encoded stream. Remove header or other part before

conversion.

-mQ: Decode MIME quoted stream. ‘_’ in quoted stream is converted to space.
-mN: Non-strict decoding.

It allows line break in the middle of the base64 encoding.

-m0: No MIME decode.

-M

MIME encode. Header style. All ASCII code and control characters are intact. Kanji conversion is performed before encoding, so this cannot be used as a picture encoder.

-MB: MIME encode Base64 stream.
-MQ: Perfome quoted encoding.

-l

Input and output code is ISO8859-1 (Latin-1) and ISO-2022-JP. -s, -e and -x are not compatible with this option.

-L[uwm]

new line mode Without this option, nkf doesn‘t convert line breaks.

-Lu: unix (LF)
-Lw: windows (CRLF)
-Lm: mac (CR)

—fj —unix —mac —msdos —windows

convert for these system

—jis —euc —sjis —mime —base64

convert for named code

—jis-input —euc-input —sjis-input —mime-input —base64-input

assume input system

—ic=`input codeset` —oc=`output codeset`

Set the input or output codeset. NKF supports following codesets and those codeset name are case insensitive.

ISO-2022-JP: a.k.a. RFC1468, 7bit JIS, JUNET
EUC-JP (eucJP-nkf): a.k.a. AT&T JIS, Japanese EUC, UJIS
eucJP-ascii: a.k.a. x-eucjp-open-19970715-ascii
eucJP-ms: a.k.a. x-eucjp-open-19970715-ms
CP51932: Microsoft Version of EUC-JP.
Shift_JIS: SJIS, MS-Kanji
CP932: a.k.a. Windows-31J
UTF-8: same as UTF-8N
UTF-8N: UTF-8 without BOM
UTF-8-BOM: UTF-8 with BOM
UTF-16: same as UTF-16BE
UTF-16BE: UTF-16 Big Endian without BOM
UTF-16BE-BOM: UTF-16 Big Endian with BOM
UTF-16LE: UTF-16 Little Endian without BOM
UTF-16LE-BOM: UTF-16 Little Endian with BOM
UTF8-MAC: NKDed UTF-8, a.k.a. UTF8-NFD (input only)

—fb-{skip, html, xml, perl, java, subchar}

Specify the way that nkf handles unassigned characters. Without this option, —fb-skip is assumed.

—prefix= `escape character` `target character` ..

When nkf converts to Shift_JIS, nkf adds a specified escape character to specified 2nd byte of Shift_JIS characters. 1st byte of argument is the escape character and following bytes are target characters.

—disable-cp932ext

Handle the characters extended in CP932 as unassigned characters.

—cap-input

Decode hex encoded characters.

—url-input

Unescape percent escaped characters.

—

Ignore rest of -option.

Constants

Name		Description
ASCII	= INT2FIX(_ASCII)	ASCII
AUTO	= INT2FIX(_AUTO)	Auto-Detect
BINARY	= INT2FIX(_BINARY)	BINARY
EUC	= INT2FIX(_EUC)	EUC-JP
JIS	= INT2FIX(_JIS)	ISO-2022-JP
NKF_RELEASE_DATE	= rb_str_new2(NKF_RELEASE_DATE)	Release date of nkf
NKF_VERSION	= rb_str_new2(NKF_VERSION)	Version of nkf
NOCONV	= INT2FIX(_NOCONV)	No conversion
SJIS	= INT2FIX(_SJIS)	Shift_JIS
UNKNOWN	= INT2FIX(_UNKNOWN)	UNKNOWN
UTF16	= INT2FIX(_UTF16)	UTF-16
UTF32	= INT2FIX(_UTF32)	UTF-32
UTF8	= INT2FIX(_UTF8)	UTF-8
VERSION	= rb_str_new2(RUBY_NKF_VERSION)	Full version string of nkf

Aliases

Method	Alias	Description
guess2	→ guess

Methods

Class

Visibility	Signature
public	guess1 (p1)
public	guess2 (p1)
public	nkf (p1, p2)

Class Method Detail

NKF.guess1(str) → integer

Returns guessed encoding of str as integer.

Algorithm described in: Ken Lunde. `Understanding Japanese Information Processing’ Sebastopol, CA: O‘Reilly & Associates.

    case NKF.guess1(input)
    when NKF::JIS
      "ISO-2022-JP"
    when NKF::SJIS
      "Shift_JIS"
    when NKF::EUC
      "EUC-JP"
    when NKF::UNKNOWN
      "UNKNOWN(ASCII)"
    when NKF::BINARY
      "BINARY"
    end

NKF.guess2(str) → integer

Returns guessed encoding of str as integer by nkf routine.

   case NKF.guess(input)
   when NKF::ASCII
     "ASCII"
   when NKF::JIS
     "ISO-2022-JP"
   when NKF::SJIS
     "Shift_JIS"
   when NKF::EUC
     "EUC-JP"
   when NKF::UTF8
     "UTF-8"
   when NKF::UTF16
     "UTF-16"
   when NKF::UNKNOWN
     "UNKNOWN"
   when NKF::BINARY
     "BINARY"
   end

NKF.nkf(opt, str) → string

Convert str and return converted result. Conversion details are specified by opt as String.

   require 'nkf'
   output = NKF.nkf("-s", input)

Note By default, nkf decodes MIME encoded string. If you want not to decode input, use NKF.nkf with -m0 flag.