/**********************************************************************
** Copyright (C) 2000-2005 Trolltech AS and its licensors.
** All rights reserved.
**
** This file is part of the Qtopia Environment.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/gpl/ for GPL licensing information.
** See below for additional copyright and license information
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
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// Most of the code here was originally written by Serika Kurusugawa
// a.k.a. Junji Takagi, and is included in Qt with the author's permission,
// and the grateful thanks of the Trolltech team.

/*! \class QSjisCodec

  \brief The QSjisCodec class provides conversion to and from Shift-JIS.

  \ingroup qtopiaemb

  The QSjisCodec class subclasses QTextCodec to provide support for
  Shift-JIS, an encoding of JIS X 0201 Latin, JIS X 0201 Kana or JIS X
  0208.

  The environment variable \c UNICODEMAP_JP can be used to fine-tune how
  QJpUnicodeConv, QEucJpCodec, QJisCodec and QSjisCodec do their work.
  The QJpUnicodeConv documentation describes how to use this variable.

  It was largely written by Serika Kurusugawa a.k.a. Junji Takagi, and
  is included in Qt with the author's permission, and the grateful
  thanks of the Trolltech team. Here is the copyright statement for
  that code:

  \quote

  Copyright (c) 1999 Serika Kurusugawa, All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met: <ol>
  <li> Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  <li> Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
  </ol>

  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  SUCH DAMAGE.

  \endquote
*/

#include "qsjiscodec.h"


static const uchar Esc = 0x1b;

#define	IsKana(c)	(((c) >= 0xa1) && ((c) <= 0xdf))
#define	IsSjisChar1(c)	((((c) >= 0x81) && ((c) <= 0x9f)) ||	\
			 (((c) >= 0xe0) && ((c) <= 0xfc)))
#define	IsSjisChar2(c)	(((c) >= 0x40) && ((c) != 0x7f) && ((c) <= 0xfc))
#define	IsUserDefinedChar1(c)	(((c) >= 0xf0) && ((c) <= 0xfc))

#define	QValidChar(u)	((u) ? QChar((ushort)(u)) : QChar::replacement)

/*!
  Creates a Shift-JIS codec.  Note that this is done automatically by
  the QApplication, you do not need construct your own.
*/
QSjisCodec::QSjisCodec() : conv(QJpUnicodeConv::newConverter(JU_Default))
{
}

/*!
  Destructs the codec.
*/

QSjisCodec::~QSjisCodec()
{
    delete conv;
}

/*!
  Returns 17.
*/
int QSjisCodec::mibEnum() const
{
    /*
    Name: Shift_JIS  (preferred MIME name)
    MIBenum: 17
    Source: A Microsoft code that extends csHalfWidthKatakana to include
	    kanji by adding a second byte when the value of the first
	    byte is in the ranges 81-9F or E0-EF.
    Alias: MS_Kanji
    Alias: csShiftJIS
    */
    return 17;
}

/*!
  \reimp
*/
QCString QSjisCodec::fromUnicode(const QString& uc, int& len_in_out) const
{
    int l = QMIN((int)uc.length(),len_in_out);
    int rlen = l*2+1;
    QCString rstr(rlen);
    uchar* cursor = (uchar*)rstr.data();
    for (int i=0; i<l; i++) {
	QChar ch = uc[i];
	uint j;
	if ( ch.row() == 0x00 && ch.cell() < 0x80 ) {
	    // ASCII
	    *cursor++ = ch.cell();
	} else if ((j = conv->UnicodeToJisx0201(ch.row(), ch.cell())) != 0) {
	    // JIS X 0201 Latin or JIS X 0201 Kana
	    *cursor++ = j;
	} else if ((j = conv->UnicodeToSjis(ch.row(), ch.cell())) != 0) {
	    // JIS X 0208
	    *cursor++ = (j >> 8);
	    *cursor++ = (j & 0xff);
	} else if ((j = conv->UnicodeToJisx0212(ch.row(), ch.cell())) != 0) {
	    // JIS X 0212 (can't be encoded in ShiftJIS !)
	    *cursor++ = 0x81;	// white square
	    *cursor++ = 0xa0;	// white square
	} else if ( ch.unicode() == 0xa0 ) {
	    *cursor++ = ' ';
	} else {
	    // Error
	    *cursor++ = '?';	// unknown char
	}
    }
    len_in_out = cursor - (uchar*)rstr.data();
    rstr.truncate(len_in_out);
    return rstr;
}

/*!
  \reimp
*/
QString QSjisCodec::toUnicode(const char* chars, int len) const
{
    QString result;
    for (int i=0; i<len; i++) {
	uchar ch = chars[i];
	if ( ch < 0x80 || IsKana(ch) ) {
	    // JIS X 0201 Latin or JIS X 0201 Kana
	    uint u = conv->Jisx0201ToUnicode(ch);
	    result += QValidChar(u);
	} else if ( IsSjisChar1(ch) ) {
	    // JIS X 0208
	    if ( i < len-1 ) {
		uchar c2 = chars[++i];
		if ( IsSjisChar2(c2) ) {
		    if ( IsUserDefinedChar1(ch) ) {
			result += QChar::replacement;
		    } else {
			uint u = conv->SjisToUnicode(ch, c2);
			result += QValidChar(u);
		    }
		} else {
		    i--;
		    result += QChar::replacement;
		}
	    } else {
		result += QChar::replacement;
	    }
	} else {
	    result += QChar::replacement;
	}
    }
    return result;
}

/*!
  \reimp
*/
const char* QSjisCodec::name() const
{
    return "SJIS";
}

/*!
  \reimp
*/
int QSjisCodec::heuristicNameMatch(const char* hint) const
{
    int score = 0;
    bool ja = FALSE;
    if (qstrnicmp(hint, "ja_JP", 5) == 0 || qstrnicmp(hint, "japan", 5) == 0) { // No tr
	score += 3;
	ja = TRUE;
    } else if (qstrnicmp(hint, "ja", 2) == 0) {
	score += 2;
	ja = TRUE;
    }
    const char *p;
    if (ja) {
	p = strchr(hint, '.');
	if (p == 0) {
	    return score - 1;
	}
	p++;
    } else {
	p = hint;
    }
    if (p) {
	if ((qstricmp(p, "mscode") == 0) ||
	    (qstricmp(p, "PCK") == 0) ||
	    (qstricmp(p, "SJIS") == 0) ||
	    (simpleHeuristicNameMatch(p, "ShiftJIS") > 0) ||
	    (simpleHeuristicNameMatch(p, "x-sjis") > 0)) {
	    return score + 4;
	}
    }
    return QTextCodec::heuristicNameMatch(hint);
}

/*!
  \reimp
*/
int QSjisCodec::heuristicContentMatch(const char* chars, int len) const
{
    int score = 0;
    for (int i=0; i<len; i++) {
	uchar ch = chars[i];
	// No nulls allowed.
	if ( !ch || ch == Esc )
	    return -1;
	if ( ch < 32 && ch != '\t' && ch != '\n' && ch != '\r' ) {
	    // Suspicious
	    if ( score )
		score--;
	} else if ( ch < 0x80 ) {
	    // Inconclusive
	    score++;
	} else if ( IsKana(ch) ) {
	    // JIS X 0201 Kana
	    score++;
	} else if ( IsSjisChar1(ch) ) {
	    // JIS X 0208-1990
	    if ( i < len-1 ) {
		uchar c2 = chars[++i];
		if ( !IsSjisChar2(c2) )
		    return -1;
		score++;
	    }
	    score++;
	} else {
	    // Invalid
	    return -1;
	}
    }
    return score;
}

class QSjisDecoder : public QTextDecoder {
    uchar buf[1];
    int nbuf;
    const QJpUnicodeConv * const conv;
public:
    QSjisDecoder(const QJpUnicodeConv *c) : nbuf(0), conv(c)
    {
    }

    QString toUnicode(const char* chars, int len)
    {
	QString result;
	for (int i=0; i<len; i++) {
	    uchar ch = chars[i];
	    switch (nbuf) {
	      case 0:
		if ( ch < 0x80 || IsKana(ch) ) {
		    // JIS X 0201 Latin or JIS X 0201 Kana
		    uint u = conv->Jisx0201ToUnicode(ch);
		    result += QValidChar(u);
		} else if ( IsSjisChar1(ch) ) {
		    // JIS X 0208
		    buf[0] = ch;
		    nbuf = 1;
		} else {
		    // Invalid
		    result += QChar::replacement;
		}
		break;
	      case 1:
		// JIS X 0208
		if ( IsSjisChar2(ch) ) {
		    if ( IsUserDefinedChar1(buf[0]) ) {
			result += QChar::replacement;
		    } else {
			uint u = conv->SjisToUnicode(buf[0], ch);
			result += QValidChar(u);
		    }
		} else {
		    // Invalid
		    result += QChar::replacement;
		}
		nbuf = 0;
		break;
	    }
	}
	return result;
    }
};

/*!
  \reimp
*/
QTextDecoder* QSjisCodec::makeDecoder() const
{
    return new QSjisDecoder(conv);
}

