/****************************************************************************
**
** Copyright (C) 1992-2006 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:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at sales@trolltech.com.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

#include "qisciicodec_p.h"
#include "qlist.h"

#ifndef QT_NO_CODECS

/*!
    \class QIsciiCodec
    \brief The QIsciiCodec class provides conversion to and from the ISCII encoding.

    \internal
*/


struct Codecs {
    const char *name;
    ushort base;
};

static const Codecs codecs [] = {
    { "Iscii-Dev", 0x900 },
    { "Iscii-Bng", 0x980 },
    { "Iscii-Pnj", 0xa00 },
    { "Iscii-Gjr", 0xa80 },
    { "Iscii-Ori", 0xb00 },
    { "Iscii-Tml", 0xb80 },
    { "Iscii-Tlg", 0xc00 },
    { "Iscii-Knd", 0xc80 },
    { "Iscii-Mlm", 0xd00 }
};

QIsciiCodec::~QIsciiCodec()
{
}

QByteArray QIsciiCodec::name() const
{
  return codecs[idx].name;
}

int QIsciiCodec::mibEnum() const
{
    /* There is no MIBEnum for Iscii */
    return -3000-idx;
}


#define INV 0xff

/* iscii range from 0xa0 - 0xff */
static const uchar iscii_to_uni_table[0x60] = {
    0x00, 0x01, 0x02, 0x03,
    0x05, 0x06, 0x07, 0x08,
    0x09, 0x0a, 0x0b, 0x0e,
    0x0f, 0x20, 0x0d, 0x12,

    0x13, 0x14, 0x11, 0x15,
    0x16, 0x17, 0x18, 0x19,
    0x1a, 0x1b, 0x1c, 0x1d,
    0x1e, 0x1f, 0x20, 0x21,

    0x22, 0x23, 0x24, 0x25,
    0x26, 0x27, 0x28, 0x29,
    0x2a, 0x2b, 0x2c, 0x2d,
    0x2e, 0x2f, 0x5f, 0x30,

    0x31, 0x32, 0x33, 0x34,
    0x35, 0x36, 0x37, 0x38,
    0x39,  INV, 0x3e, 0x3f,
    0x40, 0x41, 0x42, 0x43,

    0x46, 0x47, 0x48, 0x45,
    0x4a, 0x4b, 0x4c, 0x49,
    0x4d, 0x3c, 0x64, 0x00,
    0x00, 0x00, 0x00, 0x00,

    0x00, 0x66, 0x67, 0x68,
    0x69, 0x6a, 0x6b, 0x6c,
    0x6d, 0x6e, 0x6f, 0x00,
    0x00, 0x00, 0x00, 0x00
};

static const uchar uni_to_iscii_table[0x80] = {
    0x00, 0xa1, 0xa2, 0xa3,
    0x00, 0xa4, 0xa5, 0xa6,
    0xa7, 0xa8, 0xa9, 0xaa,
    0x00, 0xae, 0xab, 0xac,

    0xad, 0xb2, 0xaf, 0xb0,
    0xb1, 0xb3, 0xb4, 0xb5,
    0xb6, 0xb7, 0xb8, 0xb9,
    0xba, 0xbb, 0xbc, 0xbd,

    0xbe, 0xbf, 0xc0, 0xc1,
    0xc2, 0xc3, 0xc4, 0xc5,
    0xc6, 0xc7, 0xc8, 0xc9,
    0xca, 0xcb, 0xcc, 0xcd,

    0xcf, 0xd0, 0xd1, 0xd2,
    0xd3, 0xd4, 0xd5, 0xd6,
    0xd7, 0xd8, 0x00, 0x00,
    0xe9, 0x00, 0xda, 0xdb,

    0xdc, 0xdd, 0xde, 0xdf,
    0x00, 0xe3, 0xe0, 0xe1,
    0xe2, 0xe7, 0xe4, 0xe5,
    0xe6, 0xe8, 0x00, 0x00,

    0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00,
    0x01, 0x02, 0x03, 0x04, // decomposable into the uc codes listed here + nukta
    0x05, 0x06, 0x07, 0xce,

    0x00, 0x00, 0x00, 0x00,
    0xea, 0x08, 0xf1, 0xf2,
    0xf3, 0xf4, 0xf5, 0xf6,
    0xf7, 0xf8, 0xf9, 0xfa,

    0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00
};

static const uchar uni_to_iscii_pairs[] = {
    0x00, 0x00,
    0x15, 0x3c, // 0x958
    0x16, 0x3c, // 0x959
    0x17, 0x3c, // 0x95a
    0x1c, 0x3c, // 0x95b
    0x21, 0x3c, // 0x95c
    0x22, 0x3c, // 0x95d
    0x2b, 0x3c, // 0x95e
    0x64, 0x64  // 0x965
};


QByteArray QIsciiCodec::convertFromUnicode(const QChar *uc, int len, ConverterState *state) const
{
    char replacement = '?';
    bool halant = false;
    if (state) {
        if (state->flags & ConvertInvalidToNull)
            replacement = 0;
        halant = state->state_data[0];
    }
    int invalid = 0;

    QByteArray result;
    result.resize(2*len); //worst case

    uchar *ch = (uchar *)result.data();

    int base = codecs[idx].base;

    for (int i =0; i < len; ++i) {
        int pos = uc[i].unicode() - base;
        if (pos > 0 && pos < 0x80) {
            uchar iscii = uni_to_iscii_table[pos];
            if (iscii > 0x80) {
                *ch++ = iscii;
            } else if (iscii) {
                const uchar *pair = uni_to_iscii_pairs + 2*iscii;
                *ch++ = *pair++;
                *ch++ = *pair++;
            } else {
                *ch++ = replacement;
                ++invalid;
            }
        } else {
            if (uc[i].unicode() == 0x200c) { // ZWNJ
                if (halant)
                    // Consonant Halant ZWNJ -> Consonant Halant Halant
                    *ch++ = 0xe8;
            } else if (uc[i].unicode() == 0x200d) { // ZWJ
                if (halant)
                    // Consonant Halant ZWJ -> Consonant Halant Nukta
                    *ch++ = 0xe9;
            } else {
                *ch++ = replacement;
                ++invalid;
            }
        }
        halant = (pos == 0x4d);
    }
    result.truncate(ch - (uchar *)result.data());

    if (state) {
        state->invalidChars += invalid;
        state->state_data[0] = halant;
    }
    return result;
}

QString QIsciiCodec::convertToUnicode(const char* chars, int len, ConverterState *state) const
{
    bool halant = false;
    if (state) {
        halant = state->state_data[0];
    }

    QString result;
    result.resize(len);
    QChar *uc = (QChar *)result.unicode();

    int base = codecs[idx].base;

    for (int i = 0; i < len; ++i) {
        ushort ch = (uchar) chars[i];
        if (ch < 0xa0)
            *uc++ = ch;
        else {
            ushort c = iscii_to_uni_table[ch - 0xa0];
            if (halant && (c == INV || c == 0xe9)) {
                // Consonant Halant INV -> Consonant Halant ZWJ
                // Consonant Halant Nukta -> Consonant Halant ZWJ
                *uc++ = QChar(0x200d);
            } else if (halant && c == 0xe8) {
                // Consonant Halant Halant -> Consonant Halant ZWNJ
                *uc++ = QChar(0x200c);
            } else {
                *uc++ = QChar(c+base);
            }
        }
        halant = ((uchar)chars[i] == 0xe8);
    }
    result.resize(uc - result.unicode());

    if (state) {
        state->state_data[0] = halant;
    }
    return result;
}
#endif // QT_NO_CODECS
