/****************************************************************************
**
** Copyright (C) 1992-2005 Trolltech AS. All rights reserved.
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
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** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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****************************************************************************/

// 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
    \reentrant
    \internal

  \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
  \code

  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:
  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  2. 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.

  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.
  \endcode
*/

#include "qtsciicodec_p.h"
#include "qlist.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))

/*!
    Destroys the text codec object.
*/
QTsciiCodec::~QTsciiCodec()
{
}

/*!
    Converts the first \a len characters in \a uc from Unicode to this
    encoding, and returns the result in a byte array. The \a state contains
    some conversion flags, and is used by the codec to maintain state
    information.
*/
QByteArray QTsciiCodec::convertFromUnicode(const QChar *uc, int len, ConverterState *state) const
{
    char replacement = '?';
    if (state) {
        if (state->flags & ConvertInvalidToNull)
            replacement = 0;
    }
    int invalid = 0;

    QByteArray rstr;
    rstr.resize(len);
    uchar* cursor = (uchar*)rstr.data();
    for (int i = 0; i < len; 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 = replacement;
            ++invalid;
        }
        *cursor++ = j;
    }
    rstr.resize(cursor - (const uchar*)rstr.constData());

    if (state) {
        state->invalidChars += invalid;
    }
    return rstr;
}

/*!
    Converts the first \a len characters in \a chars from this encoding
    to Unicode, and returns the result in a QString. The \a state contains
    some conversion flags, and is used by the codec to maintain state
    information.
*/
QString QTsciiCodec::convertToUnicode(const char* chars, int len, ConverterState *state) const
{
    QChar replacement = QChar::ReplacementCharacter;
    if (state) {
        if (state->flags & ConvertInvalidToNull)
            replacement = QChar::Null;
    }
    int invalid = 0;

    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++;
                if (c)
                    result += QChar(c);
                else {
                    result += replacement;
                    ++invalid;
                }
            }
        } else {
            // Invalid
            result += replacement;
            ++invalid;
        }
    }

    if (state) {
        state->invalidChars += invalid;
    }
    return result;
}

/*!
    Returns the official name for the encoding that is handled by the codec.

    \sa QTextCodec::name()
*/
QByteArray QTsciiCodec::name() const
{
    return "TSCII";
}

/*!
    Returns the MIB enum for the encoding.

    \sa QTextCodec::mibEnum()
*/
int QTsciiCodec::mibEnum() const
{
  /* There is no MIBEnum for TSCII now */
  return -3197;
}

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

