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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 Qt team.

/*! \class QJisCodec

    \reentrant

    \internal

*/

#include "qjiscodec.h"

#include "qlist.h"

QT_BEGIN_NAMESPACE

#ifndef QT_NO_TEXTCODEC

enum {

    Esc = 0x1b,

    So = 0x0e,         // Shift Out

    Si = 0x0f,         // Shift In

    ReverseSolidus = 0x5c,

    YenSign = 0x5c,

    Tilde = 0x7e,

    Overline = 0x7e

};

#define        IsKana(c)        (((c) >= 0xa1) && ((c) <= 0xdf))

#define        IsJisChar(c)        (((c) >= 0x21) && ((c) <= 0x7e))

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

enum Iso2022State{ Ascii, MinState = Ascii,

                   JISX0201_Latin, JISX0201_Kana,

                   JISX0208_1978, JISX0208_1983,

                   JISX0212, MaxState = JISX0212,

                   UnknownState };

static const char Esc_CHARS[] = "()*+-./";

static const char Esc_Ascii[]                 = {Esc, '(', 'B', 0 };

static const char Esc_JISX0201_Latin[]        = {Esc, '(', 'J', 0 };

static const char Esc_JISX0201_Kana[]        = {Esc, '(', 'I', 0 };

static const char Esc_JISX0208_1978[]        = {Esc, '$', '@', 0 };

static const char Esc_JISX0208_1983[]        = {Esc, '$', 'B', 0 };

static const char Esc_JISX0212[]        = {Esc, '$', '(', 'D', 0 };

static const char * const Esc_SEQ[] = { Esc_Ascii,

                                        Esc_JISX0201_Latin,

                                        Esc_JISX0201_Kana,

                                        Esc_JISX0208_1978,

                                        Esc_JISX0208_1983,

                                        Esc_JISX0212 };

/*! \internal */

QJisCodec::QJisCodec() : conv(QJpUnicodeConv::newConverter(QJpUnicodeConv::Default))

{

}

/*! \internal */

QJisCodec::~QJisCodec()

{

    delete (QJpUnicodeConv*)conv;

    conv = 0;

}

QByteArray QJisCodec::convertFromUnicode(const QChar *uc, int len, ConverterState *cs) const

{

    char replacement = '?';

    if (cs) {

        if (cs->flags & ConvertInvalidToNull)

            replacement = 0;

    }

    int invalid = 0;

    QByteArray result;

    Iso2022State state = Ascii;

    Iso2022State prev = Ascii;

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

        QChar ch = uc[i];

        uint j;

        if (ch.row() == 0x00 && ch.cell() < 0x80) {

            // Ascii

            if (state != JISX0201_Latin ||

                ch.cell() == ReverseSolidus || ch.cell() == Tilde) {

                state = Ascii;

            }

            j = ch.cell();

        } else if ((j = conv->unicodeToJisx0201(ch.row(), ch.cell())) != 0) {

            if (j < 0x80) {

                // JIS X 0201 Latin

                if (state != Ascii ||

                    ch.cell() == YenSign || ch.cell() == Overline) {

                    state = JISX0201_Latin;

                }

            } else {

                // JIS X 0201 Kana

                state = JISX0201_Kana;

                j &= 0x7f;

            }

        } else if ((j = conv->unicodeToJisx0208(ch.row(), ch.cell())) != 0) {

            // JIS X 0208

            state = JISX0208_1983;

        } else if ((j = conv->unicodeToJisx0212(ch.row(), ch.cell())) != 0) {

            // JIS X 0212

            state = JISX0212;

        } else {

            // Invalid

            state = UnknownState;

            j = replacement;

            ++invalid;

        }

        if (state != prev) {

            if (state == UnknownState) {

                result += Esc_Ascii;

            } else {

                result += Esc_SEQ[state - MinState];

            }

            prev = state;

        }

        if (j < 0x0100) {

            result += j & 0xff;

        } else {

            result += (j >> 8) & 0xff;

            result += j & 0xff;

        }

    }

    if (prev != Ascii) {

        result += Esc_Ascii;

    }

    if (cs) {

        cs->invalidChars += invalid;

    }

    return result;

}

QString QJisCodec::convertToUnicode(const char* chars, int len, ConverterState *cs) const

{

    uchar buf[4] = {0, 0, 0, 0};

    int nbuf = 0;

    Iso2022State state = Ascii, prev = Ascii;

    bool esc = false;

    QChar replacement = QChar::ReplacementCharacter;

    if (cs) {

        if (cs->flags & ConvertInvalidToNull)

            replacement = QChar::Null;

        nbuf = cs->remainingChars;

        buf[0] = (cs->state_data[0] >> 24) & 0xff;

        buf[1] = (cs->state_data[0] >> 16) & 0xff;

        buf[2] = (cs->state_data[0] >>  8) & 0xff;

        buf[3] = (cs->state_data[0] >>  0) & 0xff;

        state = (Iso2022State)((cs->state_data[1] >>  0) & 0xff);

        prev = (Iso2022State)((cs->state_data[1] >>  8) & 0xff);

        esc = cs->state_data[2];

    }

    int invalid = 0;

    QString result;

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

        uchar ch = chars[i];

        if (esc) {

            // Escape sequence

            state = UnknownState;

            switch (nbuf) {

            case 0:

                if (ch == '$' || strchr(Esc_CHARS, ch)) {

                    buf[nbuf++] = ch;

                } else {

                    nbuf = 0;

                    esc = false;

                }

                break;

            case 1:

                if (buf[0] == '$') {

                    if (strchr(Esc_CHARS, ch)) {

                        buf[nbuf++] = ch;

                    } else {

                        switch (ch) {

                        case '@':

                            state = JISX0208_1978;        // Esc $ @

                            break;

                        case 'B':

                            state = JISX0208_1983;        // Esc $ B

                            break;

                        }

                        nbuf = 0;

                        esc = false;

                    }

                } else {

                    if (buf[0] == '(') {

                        switch (ch) {

                        case 'B':

                            state = Ascii;        // Esc (B

                            break;

                        case 'I':

                            state = JISX0201_Kana;        // Esc (I

                            break;

                        case 'J':

                            state = JISX0201_Latin;        // Esc (J

                            break;

                        }

                    }

                    nbuf = 0;

                    esc = false;

                }

                break;

            case 2:

                if (buf[1] == '(') {

                    switch (ch) {

                    case 'D':

                        state = JISX0212;        // Esc $ (D

                        break;

                    }

                }

                nbuf = 0;

                esc = false;

                break;

            }

        } else {

            if (ch == Esc) {

                // Escape sequence

                nbuf = 0;

                esc = true;

            } else if (ch == So) {

                // Shift out

                prev = state;

                state = JISX0201_Kana;

                nbuf = 0;

            } else if (ch == Si) {

                // Shift in

                if (prev == Ascii || prev == JISX0201_Latin) {

                    state = prev;

                } else {

                    state = Ascii;

                }

                nbuf = 0;

            } else {

                uint u;

                switch (nbuf) {

                case 0:

                    switch (state) {

                    case Ascii:

                        if (ch < 0x80) {

                            result += QLatin1Char(ch);

                            break;

                        }

                        /* fall through */

                    case JISX0201_Latin:

                        u = conv->jisx0201ToUnicode(ch);

                        result += QValidChar(u);

                        break;

                    case JISX0201_Kana:

                        u = conv->jisx0201ToUnicode(ch | 0x80);

                        result += QValidChar(u);

                        break;

                    case JISX0208_1978:

                    case JISX0208_1983:

                    case JISX0212:

                        buf[nbuf++] = ch;

                        break;

                    default:

                        result += QChar::ReplacementCharacter;

                        break;

                    }

                    break;

                case 1:

                    switch (state) {

                    case JISX0208_1978:

                    case JISX0208_1983:

                        u = conv->jisx0208ToUnicode(buf[0] & 0x7f, ch & 0x7f);

                        result += QValidChar(u);

                        break;

                    case JISX0212:

                        u = conv->jisx0212ToUnicode(buf[0] & 0x7f, ch & 0x7f);

                        result += QValidChar(u);

                        break;

                    default:

                        result += replacement;

                        ++invalid;

                        break;

                    }

                    nbuf = 0;

                    break;

                }

            }

        }

    }

    if (cs) {

        cs->remainingChars = nbuf;

        cs->invalidChars += invalid;

        cs->state_data[0] = (buf[0] << 24) + (buf[1] << 16) + (buf[2] << 8) + buf[3];

        cs->state_data[1] = (prev << 8) + state;

        cs->state_data[2] = esc;

    }

    return result;

}

/*! \internal */

int QJisCodec::_mibEnum()

{

    return 39;

}

/*! \internal */

QByteArray QJisCodec::_name()

{

    return "ISO-2022-JP";

}

/*!

    Returns the codec's mime name.

*/

QList<QByteArray> QJisCodec::_aliases()

{

    QList<QByteArray> list;

    list << "JIS7"; // Qt 3 compat

    return list;

}

#endif // QT_NO_TEXTCODEC

QT_END_NAMESPACE