NKF

Module

NKF - Ruby extension for Network Kanji Filter

Description

This is a Ruby Extension version of nkf (Network Kanji Filter). It converts the first argument and returns 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 -w32

Output code is ISO-2022-JP (7bit JIS), Shift_JIS, EUC-JP, UTF-8N, UTF-16BE, UTF-32BE. Without this option and compile option, ISO-2022-JP is assumed.

-J -S -E -W -W16 -W32

Input assumption is JIS 7 bit, Shift_JIS, EUC-JP, UTF-8, UTF-16, UTF-32.

-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: Perform 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
Windows-31J: a.k.a. CP932
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
UTF-32: same as UTF-32BE
UTF-32BE: UTF-32 Big Endian without BOM
UTF-32BE-BOM: UTF-32 Big Endian with BOM
UTF-32LE: UTF-32 Little Endian without BOM
UTF-32LE-BOM: UTF-32 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.

–no-cp932ext

Handle the characters extended in CP932 as unassigned characters.

–no-best-fit-chars

When Unicode to Encoded byte conversion, don’t convert characters which is not round trip safe. When Unicode to Unicode conversion, with this and -x option, nkf can be used as UTF converter. (In other words, without this and -x option, nkf doesn’t save some characters)

When nkf convert string which related to path, you should use this option.

–cap-input

Decode hex encoded characters.

–url-input

Unescape percent escaped characters.

–

Ignore rest of -option.

Constants

          
            static VALUE
rb_nkf_guess(VALUE obj, VALUE src)
{
    reinit();

    input_ctr = 0;
    input = (unsigned char *)StringValuePtr(src);
    i_len = RSTRING_LENINT(src);

    guess_f = TRUE;
    kanji_convert( NULL );
    guess_f = FALSE;

    return rb_enc_from_encoding(rb_nkf_enc_get(get_guessed_code()));
}

Returns guessed encoding of str by nkf routine.

NKF.nkf(opt, str) => string

ext/nkf/nkf.c View on GitHub

          
            static VALUE
rb_nkf_convert(VALUE obj, VALUE opt, VALUE src)
{
    VALUE tmp;
    reinit();
    nkf_split_options(StringValueCStr(opt));
    if (!output_encoding) rb_raise(rb_eArgError, "no output encoding given");

    switch (nkf_enc_to_index(output_encoding)) {
    case UTF_8_BOM:    output_encoding = nkf_enc_from_index(UTF_8); break;
    case UTF_16BE_BOM: output_encoding = nkf_enc_from_index(UTF_16BE); break;
    case UTF_16LE_BOM: output_encoding = nkf_enc_from_index(UTF_16LE); break;
    case UTF_32BE_BOM: output_encoding = nkf_enc_from_index(UTF_32BE); break;
    case UTF_32LE_BOM: output_encoding = nkf_enc_from_index(UTF_32LE); break;
    }
    output_bom_f = FALSE;

    incsize = INCSIZE;

    input_ctr = 0;
    input = (unsigned char *)StringValuePtr(src);
    i_len = RSTRING_LENINT(src);
    tmp = rb_str_new(0, i_len*3 + 10);

    output_ctr = 0;
    output     = (unsigned char *)RSTRING_PTR(tmp);
    o_len      = RSTRING_LENINT(tmp);
    *output    = '\0';

    /* use _result_ begin*/
    result = tmp;
    kanji_convert(NULL);
    result = Qnil;
    /* use _result_ end */

    rb_str_set_len(tmp, output_ctr);

    if (mimeout_f)
        rb_enc_associate(tmp, rb_usascii_encoding());
    else
        rb_enc_associate(tmp, rb_nkf_enc_get(nkf_enc_name(output_encoding)));

    return tmp;
}

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

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