/****************************************************************************
**
** Copyright (C) 1992-2004 Trolltech AS. All rights reserved.
**
** This file is part of the core module of the Qt Toolkit.
**
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** accordance with the Qt Preview License Agreement provided with the
** Software.
**
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** information about Qt Commercial License Agreements.
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** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

// Most of the code here was originally written by Hans Petter Bieker,
// and is included in Qt with the author's permission, and the grateful
// thanks of the Trolltech team.

/*! \class QTsciiCodec qtsciicodec.h
    \reentrant
    \ingroup i18n

  \brief The QTsciiCodec class provides conversion to and from the Tamil TSCII encoding.

  TSCII, formally the Tamil Standard Code Information Interchange
  specification, is a commonly used charset for Tamils. The
  official page for the standard is at
  \link http://www.tamil.net/tscii/ http://www.tamil.net/tscii/\endlink

  This codec uses the mapping table found at
  \link http://www.geocities.com/Athens/5180/tsciiset.html
  http://www.geocities.com/Athens/5180/tsciiset.html\endlink.
  Tamil uses composed Unicode which might cause some
  problems if you are using Unicode fonts instead of TSCII fonts.

  Most of the code here  was written by Hans Petter Bieker
  and is included in Qt with the author's permission and the
  grateful thanks of the Trolltech team.
  Here is the copyright statement for the code as it was at the
  point of contribution. Trolltech's subsequent modifications
  are covered by the usual copyright for Qt.

  \legalese

  Copyright (C) 2000 Hans Petter Bieker. All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  \list 1
  \i Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
  \i 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.
  \endlist

  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.
*/

#include "qtsciicodec_p.h"

#ifndef QT_NO_CODECS

static unsigned char qt_UnicodeToTSCII(ushort u1, ushort u2, ushort u3);
static unsigned int qt_TSCIIToUnicode(unsigned int code, uint *s);

#define IsTSCIIChar(c)        (((c) >= 0x80) && ((c) <= 0xfd))

/*! \reimp */
int QTsciiCodec::mibEnum() const
{
  /* There is no MIBEnum for TSCII now */
  return 2028;
}

/*! \reimp */
QByteArray QTsciiCodec::fromUnicode(const QString& uc, int& lenInOut) const
{
    int l = qMin((int)uc.length(), lenInOut);
    QByteArray rstr;
    rstr.resize(l);
    uchar* cursor = (uchar*)rstr.data();
    for (int i = 0; i < l; i++) {
        QChar ch = uc[i];
        uchar j;
        if (ch.row() == 0x00 && ch.cell() < 0x80) {
            // ASCII
            j = ch.cell();
        } else if ((j = qt_UnicodeToTSCII(uc[i].unicode(),
                                          uc[i + 1].unicode(),
                                          uc[i + 2].unicode()))) {
            // We have to check the combined chars first!
            i += 2;
        } else if ((j = qt_UnicodeToTSCII(uc[i].unicode(),
                                          uc[i + 1].unicode(), 0))) {
            i++;
        } else if ((j = qt_UnicodeToTSCII(uc[i].unicode(), 0, 0))) {
        } else {
            // Error
            j = '?';        // unknown char
        }
        *cursor++ = j;
    }
    lenInOut = cursor - (const uchar*)rstr.constData();
    rstr.resize(lenInOut);
    return rstr;
}

/*! \reimp */
QString QTsciiCodec::toUnicode(const char* chars, int len) const
{
    QString result;
    for (int i = 0; i < len; i++) {
        uchar ch = chars[i];
        if (ch < 0x80) {
            // ASCII
            result += QLatin1Char(ch);
        } else if (IsTSCIIChar(ch)) {
            // TSCII
            uint s[3];
            uint u = qt_TSCIIToUnicode(ch, s);
            uint *p = s;
            while (u--) {
                uint c = *p++;
                result += c ? QChar(c) : QChar(QChar::ReplacementCharacter);
            }
        } else {
            // Invalid
            result += QChar(QChar::ReplacementCharacter);
        }
    }

    return result;
}

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

/*! \reimp */
int QTsciiCodec::heuristicNameMatch(const char* hint) const
{
    const char *p = strchr(hint, '.');
    if (p)
        p++;
    else
        p = hint;
    if (qstricmp(p, "TSCII") == 0)
        return 4;
    return QTextCodec::heuristicNameMatch(hint);
}

/*! \reimp */
int QTsciiCodec::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)
            return -1;
        if (ch < 32 && ch != '\t' && ch != '\n' && ch != '\r') {
            // Suspicious
            if (score)
                score--;
        } else if (ch < 0x80) {
            // Inconclusive
        } else if (IsTSCIIChar(ch)) {
            score++;
        } else {
            // Invalid
            return -1;
        }
    }
    return score;
}

static const int UnToTsLast = 124; // 125 items -- so the last will be 124
static const ushort UnToTs [][4] = {
    // *Sorted* list of TSCII maping for unicode chars
    //FIRST  SECOND  THIRD   TSCII
    {0x00A0, 0x0000, 0x0000, 0xA0},
    {0x00A9, 0x0000, 0x0000, 0xA9},
    {0x0B83, 0x0000, 0x0000, 0xB7},
    {0x0B85, 0x0000, 0x0000, 0xAB},
    {0x0B86, 0x0000, 0x0000, 0xAC},
    {0x0B87, 0x0000, 0x0000, 0xAD},
    {0x0B88, 0x0000, 0x0000, 0xAE},
    {0x0B89, 0x0000, 0x0000, 0xAF},
    {0x0B8A, 0x0000, 0x0000, 0xB0},
    {0x0B8E, 0x0000, 0x0000, 0xB1},
    {0x0B8F, 0x0000, 0x0000, 0xB2},
    {0x0B90, 0x0000, 0x0000, 0xB3},
    {0x0B92, 0x0000, 0x0000, 0xB4},
    {0x0B93, 0x0000, 0x0000, 0xB5},
    {0x0B94, 0x0000, 0x0000, 0xB6},
    {0x0B95, 0x0000, 0x0000, 0xB8},
    {0x0B95, 0x0B82, 0x0000, 0xEC},
    {0x0B95, 0x0BC1, 0x0000, 0xCC},
    {0x0B95, 0x0BC2, 0x0000, 0xDC},
    {0x0B99, 0x0000, 0x0000, 0xB9},
    {0x0B99, 0x0B82, 0x0000, 0xED},
    {0x0B99, 0x0BC1, 0x0000, 0x99},
    {0x0B99, 0x0BC2, 0x0000, 0x9B},
    {0x0B9A, 0x0000, 0x0000, 0xBA},
    {0x0B9A, 0x0B82, 0x0000, 0xEE},
    {0x0B9A, 0x0BC1, 0x0000, 0xCD},
    {0x0B9A, 0x0BC2, 0x0000, 0xDD},
    {0x0B9C, 0x0000, 0x0000, 0x83},
    {0x0B9C, 0x0B82, 0x0000, 0x88},
    {0x0B9E, 0x0000, 0x0000, 0xBB},
    {0x0B9E, 0x0B82, 0x0000, 0xEF},
    {0x0B9E, 0x0BC1, 0x0000, 0x9A},
    {0x0B9E, 0x0BC2, 0x0000, 0x9C},
    {0x0B9F, 0x0000, 0x0000, 0xBC},
    {0x0B9F, 0x0B82, 0x0000, 0xF0},
    {0x0B9F, 0x0BBF, 0x0000, 0xCA},
    {0x0B9F, 0x0BC0, 0x0000, 0xCB},
    {0x0B9F, 0x0BC1, 0x0000, 0xCE},
    {0x0B9F, 0x0BC2, 0x0000, 0xDE},
    {0x0BA1, 0x0B82, 0x0000, 0xF2},
    {0x0BA3, 0x0000, 0x0000, 0xBD},
    {0x0BA3, 0x0B82, 0x0000, 0xF1},
    {0x0BA3, 0x0BC1, 0x0000, 0xCF},
    {0x0BA3, 0x0BC2, 0x0000, 0xDF},
    {0x0BA4, 0x0000, 0x0000, 0xBE},
    {0x0BA4, 0x0BC1, 0x0000, 0xD0},
    {0x0BA4, 0x0BC2, 0x0000, 0xE0},
    {0x0BA8, 0x0000, 0x0000, 0xBF},
    {0x0BA8, 0x0B82, 0x0000, 0xF3},
    {0x0BA8, 0x0BC1, 0x0000, 0xD1},
    {0x0BA8, 0x0BC2, 0x0000, 0xE1},
    {0x0BA9, 0x0000, 0x0000, 0xC9},
    {0x0BA9, 0x0B82, 0x0000, 0xFD},
    {0x0BA9, 0x0BC1, 0x0000, 0xDB},
    {0x0BA9, 0x0BC2, 0x0000, 0xEB},
    {0x0BAA, 0x0000, 0x0000, 0xC0},
    {0x0BAA, 0x0B82, 0x0000, 0xF4},
    {0x0BAA, 0x0BC1, 0x0000, 0xD2},
    {0x0BAA, 0x0BC2, 0x0000, 0xE2},
    {0x0BAE, 0x0000, 0x0000, 0xC1},
    {0x0BAE, 0x0B82, 0x0000, 0xF5},
    {0x0BAE, 0x0BC1, 0x0000, 0xD3},
    {0x0BAE, 0x0BC2, 0x0000, 0xE3},
    {0x0BAF, 0x0000, 0x0000, 0xC2},
    {0x0BAF, 0x0B82, 0x0000, 0xF6},
    {0x0BAF, 0x0BC1, 0x0000, 0xD4},
    {0x0BAF, 0x0BC2, 0x0000, 0xE4},
    {0x0BB0, 0x0000, 0x0000, 0xC3},
    {0x0BB0, 0x0B82, 0x0000, 0xF7},
    {0x0BB0, 0x0BC1, 0x0000, 0xD5},
    {0x0BB0, 0x0BC2, 0x0000, 0xE5},
    {0x0BB1, 0x0000, 0x0000, 0xC8},
    {0x0BB1, 0x0B82, 0x0000, 0xFC},
    {0x0BB1, 0x0BC1, 0x0000, 0xDA},
    {0x0BB1, 0x0BC2, 0x0000, 0xEA},
    {0x0BB2, 0x0000, 0x0000, 0xC4},
    {0x0BB2, 0x0B82, 0x0000, 0xF8},
    {0x0BB2, 0x0BC1, 0x0000, 0xD6},
    {0x0BB2, 0x0BC2, 0x0000, 0xE6},
    {0x0BB3, 0x0000, 0x0000, 0xC7},
    {0x0BB3, 0x0B82, 0x0000, 0xFB},
    {0x0BB3, 0x0BC1, 0x0000, 0xD9},
    {0x0BB3, 0x0BC2, 0x0000, 0xE9},
    {0x0BB4, 0x0000, 0x0000, 0xC6},
    {0x0BB4, 0x0B82, 0x0000, 0xFA},
    {0x0BB4, 0x0BC1, 0x0000, 0xD8},
    {0x0BB4, 0x0BC2, 0x0000, 0xE8},
    {0x0BB5, 0x0000, 0x0000, 0xC5},
    {0x0BB5, 0x0B82, 0x0000, 0xF9},
    {0x0BB5, 0x0BC1, 0x0000, 0xD7},
    {0x0BB5, 0x0BC2, 0x0000, 0xE7},
    {0x0BB7, 0x0000, 0x0000, 0x84},
    {0x0BB7, 0x0B82, 0x0000, 0x89},
    {0x0BB8, 0x0000, 0x0000, 0x85},
    {0x0BB8, 0x0B82, 0x0000, 0x8A},
    {0x0BB9, 0x0000, 0x0000, 0x86},
    {0x0BB9, 0x0B82, 0x0000, 0x8B},
    {0x0BBE, 0x0000, 0x0000, 0xA1},
    {0x0BBF, 0x0000, 0x0000, 0xA2},
    {0x0BC0, 0x0000, 0x0000, 0xA3},
    {0x0BC1, 0x0000, 0x0000, 0xA4},
    {0x0BC2, 0x0000, 0x0000, 0xA5},
    {0x0BC6, 0x0000, 0x0000, 0xA6},
    {0x0BC7, 0x0000, 0x0000, 0xA7},
    {0x0BC8, 0x0000, 0x0000, 0xA8},
    {0x0BCC, 0x0000, 0x0000, 0xAA},
    {0x0BE6, 0x0000, 0x0000, 0x80},
    {0x0BE7, 0x0000, 0x0000, 0x81},
    {0x0BE7, 0x0BB7, 0x0000, 0x87},
    {0x0BE7, 0x0BB7, 0x0B82, 0x8C},
    {0x0BE8, 0x0000, 0x0000, 0x8D},
    {0x0BE9, 0x0000, 0x0000, 0x8E},
    {0x0BEA, 0x0000, 0x0000, 0x8F},
    {0x0BEB, 0x0000, 0x0000, 0x90},
    {0x0BEC, 0x0000, 0x0000, 0x95},
    {0x0BED, 0x0000, 0x0000, 0x96},
    {0x0BEE, 0x0000, 0x0000, 0x97},
    {0x0BEF, 0x0000, 0x0000, 0x98},
    {0x0BF0, 0x0000, 0x0000, 0x9D},
    {0x0BF1, 0x0000, 0x0000, 0x9E},
    {0x0BF2, 0x0000, 0x0000, 0x9F},
    {0x2018, 0x0000, 0x0000, 0x91},
    {0x2019, 0x0000, 0x0000, 0x92},
    {0x201C, 0x0000, 0x0000, 0x93},
    {0x201C, 0x0000, 0x0000, 0x94}
};

static const ushort TsToUn [][3] = {
    // Starting at 0x80
    {0x0BE6, 0x0000, 0x0000},
    {0x0BE7, 0x0000, 0x0000},
    {0x0000, 0x0000, 0x0000}, // unknown
    {0x0B9C, 0x0000, 0x0000},
    {0x0BB7, 0x0000, 0x0000},
    {0x0BB8, 0x0000, 0x0000},
    {0x0BB9, 0x0000, 0x0000},
    {0x0BE7, 0x0BB7, 0x0000},
    {0x0B9C, 0x0B82, 0x0000},
    {0x0BB7, 0x0B82, 0x0000},
    {0x0BB8, 0x0B82, 0x0000},
    {0x0BB9, 0x0B82, 0x0000},
    {0x0BE7, 0x0BB7, 0x0B82},
    {0x0BE8, 0x0000, 0x0000},
    {0x0BE9, 0x0000, 0x0000},
    {0x0BEA, 0x0000, 0x0000},
    {0x0BEB, 0x0000, 0x0000},
    {0x2018, 0x0000, 0x0000},
    {0x2019, 0x0000, 0x0000},
    {0x201C, 0x0000, 0x0000},
    {0x201C, 0x0000, 0x0000}, // two of the same??
    {0x0BEC, 0x0000, 0x0000},
    {0x0BED, 0x0000, 0x0000},
    {0x0BEE, 0x0000, 0x0000},
    {0x0BEF, 0x0000, 0x0000},
    {0x0B99, 0x0BC1, 0x0000},
    {0x0B9E, 0x0BC1, 0x0000},
    {0x0B99, 0x0BC2, 0x0000},
    {0x0B9E, 0x0BC2, 0x0000},
    {0x0BF0, 0x0000, 0x0000},
    {0x0BF1, 0x0000, 0x0000},
    {0x0BF2, 0x0000, 0x0000},
    {0x00A0, 0x0000, 0x0000},
    {0x0BBE, 0x0000, 0x0000},
    {0x0BBF, 0x0000, 0x0000},
    {0x0BC0, 0x0000, 0x0000},
    {0x0BC1, 0x0000, 0x0000},
    {0x0BC2, 0x0000, 0x0000},
    {0x0BC6, 0x0000, 0x0000},
    {0x0BC7, 0x0000, 0x0000},
    {0x0BC8, 0x0000, 0x0000},
    {0x00A9, 0x0000, 0x0000},
    {0x0BCC, 0x0000, 0x0000},
    {0x0B85, 0x0000, 0x0000},
    {0x0B86, 0x0000, 0x0000},
    {0x0B87, 0x0000, 0x0000},
    {0x0B88, 0x0000, 0x0000},
    {0x0B89, 0x0000, 0x0000},
    {0x0B8A, 0x0000, 0x0000},
    {0x0B8E, 0x0000, 0x0000},
    {0x0B8F, 0x0000, 0x0000},
    {0x0B90, 0x0000, 0x0000},
    {0x0B92, 0x0000, 0x0000},
    {0x0B93, 0x0000, 0x0000},
    {0x0B94, 0x0000, 0x0000},
    {0x0B83, 0x0000, 0x0000},
    {0x0B95, 0x0000, 0x0000},
    {0x0B99, 0x0000, 0x0000},
    {0x0B9A, 0x0000, 0x0000},
    {0x0B9E, 0x0000, 0x0000},
    {0x0B9F, 0x0000, 0x0000},
    {0x0BA3, 0x0000, 0x0000},
    {0x0BA4, 0x0000, 0x0000},
    {0x0BA8, 0x0000, 0x0000},
    {0x0BAA, 0x0000, 0x0000},
    {0x0BAE, 0x0000, 0x0000},
    {0x0BAF, 0x0000, 0x0000},
    {0x0BB0, 0x0000, 0x0000},
    {0x0BB2, 0x0000, 0x0000},
    {0x0BB5, 0x0000, 0x0000},
    {0x0BB4, 0x0000, 0x0000},
    {0x0BB3, 0x0000, 0x0000},
    {0x0BB1, 0x0000, 0x0000},
    {0x0BA9, 0x0000, 0x0000},
    {0x0B9F, 0x0BBF, 0x0000},
    {0x0B9F, 0x0BC0, 0x0000},
    {0x0B95, 0x0BC1, 0x0000},
    {0x0B9A, 0x0BC1, 0x0000},
    {0x0B9F, 0x0BC1, 0x0000},
    {0x0BA3, 0x0BC1, 0x0000},
    {0x0BA4, 0x0BC1, 0x0000},
    {0x0BA8, 0x0BC1, 0x0000},
    {0x0BAA, 0x0BC1, 0x0000},
    {0x0BAE, 0x0BC1, 0x0000},
    {0x0BAF, 0x0BC1, 0x0000},
    {0x0BB0, 0x0BC1, 0x0000},
    {0x0BB2, 0x0BC1, 0x0000},
    {0x0BB5, 0x0BC1, 0x0000},
    {0x0BB4, 0x0BC1, 0x0000},
    {0x0BB3, 0x0BC1, 0x0000},
    {0x0BB1, 0x0BC1, 0x0000},
    {0x0BA9, 0x0BC1, 0x0000},
    {0x0B95, 0x0BC2, 0x0000},
    {0x0B9A, 0x0BC2, 0x0000},
    {0x0B9F, 0x0BC2, 0x0000},
    {0x0BA3, 0x0BC2, 0x0000},
    {0x0BA4, 0x0BC2, 0x0000},
    {0x0BA8, 0x0BC2, 0x0000},
    {0x0BAA, 0x0BC2, 0x0000},
    {0x0BAE, 0x0BC2, 0x0000},
    {0x0BAF, 0x0BC2, 0x0000},
    {0x0BB0, 0x0BC2, 0x0000},
    {0x0BB2, 0x0BC2, 0x0000},
    {0x0BB5, 0x0BC2, 0x0000},
    {0x0BB4, 0x0BC2, 0x0000},
    {0x0BB3, 0x0BC2, 0x0000},
    {0x0BB1, 0x0BC2, 0x0000},
    {0x0BA9, 0x0BC2, 0x0000},
    {0x0B95, 0x0B82, 0x0000},
    {0x0B99, 0x0B82, 0x0000},
    {0x0B9A, 0x0B82, 0x0000},
    {0x0B9E, 0x0B82, 0x0000},
    {0x0B9F, 0x0B82, 0x0000},
    {0x0BA3, 0x0B82, 0x0000},
    {0x0BA1, 0x0B82, 0x0000},
    {0x0BA8, 0x0B82, 0x0000},
    {0x0BAA, 0x0B82, 0x0000},
    {0x0BAE, 0x0B82, 0x0000},
    {0x0BAF, 0x0B82, 0x0000},
    {0x0BB0, 0x0B82, 0x0000},
    {0x0BB2, 0x0B82, 0x0000},
    {0x0BB5, 0x0B82, 0x0000},
    {0x0BB4, 0x0B82, 0x0000},
    {0x0BB3, 0x0B82, 0x0000},
    {0x0BB1, 0x0B82, 0x0000},
    {0x0BA9, 0x0B82, 0x0000}
};

static int cmp(const ushort *s1, const ushort *s2, size_t len)
{
    int diff = 0;

    while (len-- && (diff = *s1++ - *s2++) == 0)
        ;

    return diff;
}

static unsigned char qt_UnicodeToTSCII(ushort u1, ushort u2, ushort u3)
{
    ushort s[3];
    s[0] = u1;
    s[1] = u2;
    s[2] = u3;

    int a = 0;  // start pos
    int b = UnToTsLast; // end pos

    // do a binary search for the composed unicode in the list
    while (a <= b) {
        int w = (a + b) / 2;
        int j = cmp(UnToTs[w], s, 3);

        if (j == 0)
            // found it
            return UnToTs[w][3];

        if (j < 0)
            a = w + 1;
        else
            b = w - 1;
    }

    return 0;
}

static unsigned int qt_TSCIIToUnicode(uint code, uint *s)
{
    int len = 0;
    for (int i = 0; i < 3; i++) {
        uint u = TsToUn[code & 0x7f][i];
        s[i] = u;
        if (s[i]) len = i + 1;
    }

    return len;
}

#endif

