// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

// 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 QEucJpCodec
    \inmodule QtCore5Compat
    \reentrant
    \internal
*/

/*
 * Copyright (C) 1999 Serika Kurusugawa, 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.
 */

#include "qeucjpcodec_p.h"

QT_BEGIN_NAMESPACE

static const uchar Ss2 = 0x8e;        // Single Shift 2
static const uchar Ss3 = 0x8f;        // Single Shift 3

/*!
  Constructs a QEucJpCodec.
*/
QEucJpCodec::QEucJpCodec() : conv(QJpUnicodeConv::newConverter(QJpUnicodeConv::Default))
{
}

/*!
  Destroys the codec.
*/
QEucJpCodec::~QEucJpCodec()
{
    delete (const QJpUnicodeConv*)conv;
    conv = 0;
}

QByteArray QEucJpCodec::convertFromUnicode(const QChar *uc, int len, ConverterState *state) const
{
    char replacement = '?';
    if (state) {
        if (state->flags & ConvertInvalidToNull)
            replacement = 0;
    }
    int invalid = 0;

    int rlen = 3*len + 1;
    QByteArray rstr;
    rstr.resize(rlen);
    uchar* cursor = (uchar*)rstr.data();
    for (int i = 0; i < len; i++) {
        QChar ch = uc[i];
        uint j;
        if (ch.unicode() < 0x80) {
            // ASCII
            *cursor++ = ch.cell();
        } else if ((j = conv->unicodeToJisx0201(ch.row(), ch.cell())) != 0) {
            if (j < 0x80) {
                // JIS X 0201 Latin ?
                *cursor++ = j;
            } else {
                // JIS X 0201 Kana
                *cursor++ = Ss2;
                *cursor++ = j;
            }
        } else if ((j = conv->unicodeToJisx0208(ch.row(), ch.cell())) != 0) {
            // JIS X 0208
            *cursor++ = (j >> 8)   | 0x80;
            *cursor++ = (j & 0xff) | 0x80;
        } else if ((j = conv->unicodeToJisx0212(ch.row(), ch.cell())) != 0) {
            // JIS X 0212
            *cursor++ = Ss3;
            *cursor++ = (j >> 8)   | 0x80;
            *cursor++ = (j & 0xff) | 0x80;
        } else {
            // Error
            *cursor++ = replacement;
            ++invalid;
        }
    }
    rstr.resize(cursor - (const uchar*)rstr.constData());

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


QString QEucJpCodec::convertToUnicode(const char* chars, int len, ConverterState *state) const
{
    uchar buf[2] = {0, 0};
    int nbuf = 0;
    QChar replacement = QChar::ReplacementCharacter;
    if (state) {
        if (state->flags & ConvertInvalidToNull)
            replacement = QChar::Null;
        nbuf = state->remainingChars;
        buf[0] = state->state_data[0];
        buf[1] = state->state_data[1];
    }
    int invalid = 0;

    QString result;
    for (int i=0; i<len; i++) {
        uchar ch = chars[i];
        switch (nbuf) {
        case 0:
            if (ch < 0x80) {
                // ASCII
                result += QLatin1Char(ch);
            } else if (ch == Ss2 || ch == Ss3) {
                // JIS X 0201 Kana or JIS X 0212
                buf[0] = ch;
                nbuf = 1;
            } else if (IsEucChar(ch)) {
                // JIS X 0208
                buf[0] = ch;
                nbuf = 1;
            } else {
                // Invalid
                result += replacement;
                ++invalid;
            }
            break;
        case 1:
            if (buf[0] == Ss2) {
                // JIS X 0201 Kana
                if (IsKana(ch)) {
                    uint u = conv->jisx0201ToUnicode(ch);
                    result += QValidChar(u);
                } else {
                    result += replacement;
                    ++invalid;
                }
                nbuf = 0;
            } else if (buf[0] == Ss3) {
                // JIS X 0212-1990
                if (IsEucChar(ch)) {
                    buf[1] = ch;
                    nbuf = 2;
                } else {
                    // Error
                    result += replacement;
                    ++invalid;
                    nbuf = 0;
                }
            } else {
                // JIS X 0208-1990
                if (IsEucChar(ch)) {
                    uint u = conv->jisx0208ToUnicode(buf[0] & 0x7f, ch & 0x7f);
                    result += QValidChar(u);
                } else {
                    // Error
                    result += replacement;
                    ++invalid;
                }
                nbuf = 0;
            }
            break;
        case 2:
            // JIS X 0212
            if (IsEucChar(ch)) {
                uint u = conv->jisx0212ToUnicode(buf[1] & 0x7f, ch & 0x7f);
                result += QValidChar(u);
            } else {
                result += replacement;
                ++invalid;
            }
            nbuf = 0;
        }
    }
    if (state) {
        state->remainingChars = nbuf;
        state->state_data[0] = buf[0];
        state->state_data[1] = buf[1];
        state->invalidChars += invalid;
    }
    return result;
}

int QEucJpCodec::_mibEnum()
{
    return 18;
}

QByteArray QEucJpCodec::_name()
{
    return "EUC-JP";
}

QT_END_NAMESPACE
