/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 1994-2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <euc.h>
#include "japanese.h"

/*
 * struct _icv_state; to keep stat
 */
struct _icv_state {
        int     _st_cset;
};

void *
_icv_open()
{
        struct _icv_state *st;

        if ((st = (struct _icv_state *)malloc(sizeof (struct _icv_state)))
                                                                        == NULL)
                return ((void *)ERR_RETURN);

        st->_st_cset = CS_0;
        return (st);
}

void
_icv_close(struct _icv_state *st)
{
        free(st);
}

size_t
_icv_iconv(struct _icv_state *st, char **inbuf, size_t *inbytesleft,
                                char **outbuf, size_t *outbytesleft)
{
        int             cset;
        unsigned char   *ip, ic;
        char                    *op;
        size_t                  ileft, oleft;
        size_t                  retval;
#ifdef  RFC1468_MODE
        unsigned short  zenkaku;
#endif

        /*
         * If inbuf and/or *inbuf are NULL, reset conversion descriptor
         * and put escape sequence if needed.
         */
        if ((inbuf == NULL) || (*inbuf == NULL)) {
                if (st->_st_cset != CS_0) {
                        if ((outbuf != NULL) && (*outbuf != NULL)
                                        && (outbytesleft != NULL)) {
                                op = *outbuf;
                                oleft = *outbytesleft;
                                if (oleft < SEQ_SBTOG0) {
                                        errno = E2BIG;
                                        return ((size_t)-1);
                                }
                                PUT(ESC);
                                PUT(SBTOG0_1);
                                PUT(F_X0201_RM);
                                *outbuf = op;
                                *outbytesleft = oleft;
                        }
                        st->_st_cset = CS_0;
                }
                return ((size_t)0);
        }

        cset = st->_st_cset;

        ip = (unsigned char *)*inbuf;
        op = *outbuf;
        ileft = *inbytesleft;
        oleft = *outbytesleft;

        /*
         * Main loop; basically 1 loop per 1 input byte
         */

        while ((int)ileft > 0) {
                GET(ic);
                if (ISASC((int)ic)) {           /* ASCII */
                        if (cset != CS_0) {
                                CHECK2BIG(SEQ_SBTOG0,1);
                                PUT(ESC);       /* to JIS X 0201 Roman */
                                PUT(SBTOG0_1);
                                PUT(F_X0201_RM);
                        }
                        cset = CS_0;
                        CHECK2BIG(JISW0,1);
                        PUT(ic);
                        continue;
                } else if (ISSJKANA(ic)) {              /* Kana starts */
#ifdef  RFC1468_MODE    /* Substitute JIS X 0208 for JIS X 0201 katakana */
                        if (cset != CS_1) {
                                CHECK2BIG(SEQ_MBTOG0_O,1);
                                cset = CS_1;
                                PUT(ESC);
                                PUT(MBTOG0_1);
                                PUT(F_X0208_83_90);
                        }
                        CHECK2BIG(JISW1,1);
                        zenkaku = halfkana2zenkakuj[ic - 0xA1];
                        ic = (unsigned char)((zenkaku >> 8) & CMASK);
                        PUT(ic);
                        ic = (unsigned char)(zenkaku & CMASK);
                        PUT(ic);
#else   /* ISO-2022-JP.UIOSF */
                        if (cset != CS_2) {
                                CHECK2BIG(SEQ_SBTOG0,1);
                                cset = CS_2;
                                PUT(ESC);
                                PUT(SBTOG0_1);
                                PUT(F_X0201_KN);
                        }
                        CHECK2BIG(JISW2,1);
                        PUT(ic & CMASK);
#endif  /* RFC1468_MODE */
                        continue;
                } else if (ISSJKANJI1(ic)) {    /* CS_1 Kanji starts */
                        if ((int)ileft > 0) {
                                if (ISSJKANJI2(*ip)) {
                                        if (cset != CS_1) {
                                                CHECK2BIG(SEQ_MBTOG0_O,1);
                                                cset = CS_1;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(F_X0208_83_90);
                                        }
                                        CHECK2BIG(JISW1,1);
#ifdef  RFC1468_MODE /* Convert VDC and UDC to GETA */
                                        if ((ic == 0x87) || (0xed <= ic )){
                                                PUT((JGETA >> 8) & CMASK);
                                                GET(ic); /* Get dummy */
                                                PUT(JGETA & CMASK);
                                                continue;
                                        }
#endif  /* RFC1468_MODE */
                                        ic = sjtojis1[(ic - 0x80)];
                                        if (*ip >= 0x9f) {
                                                ic++;
                                        }
                                        PUT(ic);
                                        GET(ic);
                                        ic = sjtojis2[ic];
                                        PUT(ic);
                                        continue;
                                } else {        /* 2nd byte is illegal */
                                        UNGET();
                                        errno = EILSEQ;
                                        retval = (size_t)ERR_RETURN;
                                        goto ret;
                                }
                        } else {                /* input fragment of Kanji */
                                UNGET();
                                errno = EINVAL;
                                retval = (size_t)ERR_RETURN;
                                goto ret;
                        }
                } else if (ISSJSUPKANJI1(ic)) { /* CS_3 Kanji starts */
                        if ((int)ileft > 0) {
                                if (ISSJKANJI2(*ip)) {
#ifdef  RFC1468_MODE    /* Substitute JIS X 0208 "Geta" for JIS X 0212 */
                                        if (cset != CS_1) {
                                                CHECK2BIG(SEQ_MBTOG0_O,1);
                                                cset = CS_1;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(F_X0208_83_90);
                                        }
                                        CHECK2BIG(JISW1,1);
                                        /* Put GETA (0x222e) */
                                        ic = (unsigned char)((JGETA >> 8) &
                                        CMASK);
                                        PUT(ic);
                                        ic = (unsigned char)(JGETA & CMASK);
                                        PUT(ic);
                                        GET(ic); /* dummy GET */
#else   /* ISO-2022-JP.UIOSF */
                                        if (cset != CS_3) {
                                                CHECK2BIG(SEQ_MBTOG0,1);
                                                cset = CS_3;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(MBTOG0_2);
                                                PUT(F_X0212_90);
                                        }
                                        CHECK2BIG(JISW3,1);
                                        ic = sjtojis1[(ic - 0x80)];
                                        if (*ip >= 0x9f) {
                                                ic++;
                                        }
                                        PUT(ic);
                                        GET(ic);
                                        ic = sjtojis2[ic];
                                        PUT(ic);
#endif  /* RFC1468_MODE */
                                        continue;
                                } else {        /* 2nd byte is illegal */
                                        UNGET();
                                        errno = EILSEQ;
                                        retval = (size_t)ERR_RETURN;
                                        goto ret;
                                }
                        } else {                /* input fragment of Kanji */
                                UNGET();
                                errno = EINVAL;
                                retval = (size_t)ERR_RETURN;
                                goto ret;
                        }
                } else if (ISSJIBM(ic) || /* Extended IBM char. area */
                        ISSJNECIBM(ic)) { /* NEC/IBM char. area */
                        /*
                         * We need a special treatment for each codes.
                         * By adding some offset number for them, we
                         * can process them as the same way of that of
                         * extended IBM chars.
                         */
                        if ((int)ileft > 0) {
                                if (ISSJKANJI2(*ip)) {
                                        unsigned short dest;
                                        dest = (ic << 8);
                                        GET(ic);
                                        dest += ic;
                                        if ((0xed40 <= dest) &&
                                                (dest <= 0xeffc)) {
                                                REMAP_NEC(dest);
                                                if (dest == 0xffff) {
                                                        goto ill_ibm;
                                                }
                                        }
                                        /*
                                         * XXX: 0xfa54 and 0xfa5b must be mapped
                                         *      to JIS0208 area. Therefore we
                                         *      have to do special treatment.
                                         */
                                        if ((cset != CS_1) &&
                                                ((dest == 0xfa54) ||
                                                (dest == 0xfa5b))) {
                                                CHECK2BIG(SEQ_MBTOG0_O,2);
                                                cset = CS_1;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(F_X0208_83_90);
                                                CHECK2BIG(JISW1,2);
                                                if (dest == 0xfa54) {
                                                        PUT(0x22);
                                                        PUT(0x4c);
                                                } else {
                                                        PUT(0x22);
                                                        PUT(0x68);
                                                }
                                                continue;
                                        }
                                        if (cset != CS_3) {
                                                CHECK2BIG(SEQ_MBTOG0,2);
                                                cset = CS_3;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(MBTOG0_2);
                                                PUT(F_X0212_90);
                                        }
                                        CHECK2BIG(JISW3,2);
                                        dest = dest - 0xfa40 -
                                                (((dest>>8) - 0xfa) * 0x40);
                                        dest = sjtoibmext[dest];
                                        if (dest == 0xffff) {
                                                /*
                                                 * Illegal code points
                                                 * in IBM-EXT area.
                                                 */
ill_ibm:
                                                UNGET();
                                                UNGET();
                                                errno = EILSEQ;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
                                        PUT(((dest>>8) & 0x7f));
                                        PUT(dest & 0x7f);
                                        continue;
                                } else {        /* 2nd byte is illegal */
                                        UNGET();
                                        errno = EILSEQ;
                                        retval = (size_t)ERR_RETURN;
                                        goto ret;
                                }
                        } else {                /* input fragment of Kanji */
                                UNGET();
                                errno = EINVAL;
                                retval = (size_t)ERR_RETURN;
                                goto ret;
                        }
                } else if ((0xeb <= ic) && (ic <= 0xec)) {
                /*
                 * Based on the draft convention of OSF-JVC CDEWG,
                 * characters in this area will be mapped to
                 * "CHIKAN-MOJI." (convertible character)
                 * So far, we'll use (0x222e) for it.
                 */
                        if ((int)ileft > 0) {
                                if (ISSJKANJI2(*ip)) {
                                        if (cset != CS_1) {
                                                CHECK2BIG(SEQ_MBTOG0_O,1);
                                                cset = CS_1;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(F_X0208_83_90);
                                        }
                                        CHECK2BIG(JISW1,1);
                                        GET(ic); /* Dummy */
                                        PUT((JGETA>>8) & CMASK);
                                        PUT(JGETA & CMASK);
                                        continue;
                                } else {        /* 2nd byte is illegal */
                                        UNGET();
                                        errno = EILSEQ;
                                        retval = (size_t)ERR_RETURN;
                                        goto ret;
                                }
                        } else {                /* input fragment of Kanji */
                                UNGET();
                                errno = EINVAL;
                                retval = (size_t)ERR_RETURN;
                                goto ret;
                        }
                } else {                        /* 1st byte is illegal */
                        UNGET();
                        errno = EILSEQ;
                        retval = (size_t)ERR_RETURN;
                        goto ret;
                }
        }
        retval = ileft;
ret:
        *inbuf = (char *)ip;
        *inbytesleft = ileft;
        *outbuf = op;
        *outbytesleft = oleft;
        st->_st_cset = cset;

        return (retval);
}