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#include "qisciicodec_p.h"

#include "qlist.h"

#ifndef QT_NO_CODECS

QT_BEGIN_NAMESPACE

/*!

    \class QIsciiCodec

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

    \internal

*/

struct Codecs {

    const char name[10];

    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;

}

static const uchar 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(2 * len, Qt::Uninitialized); //worst case

    uchar *ch = reinterpret_cast<uchar *>(result.data());

    const int base = codecs[idx].base;

    for (int i =0; i < len; ++i) {

        const ushort codePoint = uc[i].unicode();

        /* The low 7 bits of ISCII is plain ASCII. However, we go all the

         * way up to 0xA0 such that we can roundtrip with convertToUnicode()'s

         * behavior. */

        if(codePoint < 0xA0) {

            *ch++ = static_cast<uchar>(codePoint);

            continue;

        }

        const int pos = codePoint - 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(len, Qt::Uninitialized);

    QChar *uc = result.data();

    const 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;

}

QT_END_NAMESPACE

#endif // QT_NO_CODECS