/*
 * 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;

        /*
         * 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 = (char *)*outbuf;
                                oleft = *outbytesleft;
                                if (oleft < SEQ_SBTOG0) {
                                        errno = E2BIG;
                                        return ((size_t)-1);
                                }
                                PUT(ESC);
                                PUT(SBTOG0_1);
                                PUT(F_X0201_RM);
                                *outbuf = (char *)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 output char
         */
        while ((int)ileft > 0) {
                GET(ic);
                if (ISASC((int)ic)) { /* ASCII */
                        if (cset != CS_0) {
                                if (oleft < SEQ_SBTOG0) {
                                        UNGET();
                                        errno = E2BIG;
                                        retval = (size_t)ERR_RETURN;
                                        goto ret;
                                }
                                PUT(ESC);       /* Kanji Out */
                                PUT(SBTOG0_1);
                                PUT(F_X0201_RM);
                        }
                        cset = CS_0;
                        if (oleft < JISW0) {
                                UNGET();
                                errno = E2BIG;
                                retval = (size_t)ERR_RETURN;
                                goto ret;
                        }
                        /* Put ASCII character */
                        PUT(ic);
                        continue;
                } else if (ISCS1((int)ic)) { /* CS_1 starts */
                        if ((int)ileft > 0) {
                                if (ISCS1(ic) && ISCS1(*ip)) {
                                        if (cset != CS_1) {
                                                if (oleft < SEQ_MBTOG0_O) {
                                                        UNGET();
                                                        errno = E2BIG;
                                                        retval =
                                                        (size_t)ERR_RETURN;
                                                        goto ret;
                                                }
                                                cset = CS_1;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(F_X0208_83_90);
                                        }
                                        if (oleft < JISW1) {
                                                UNGET();
                                                errno = E2BIG;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
#ifdef  RFC1468_MODE /* Convert VDC and UDC to GETA */
                                        if ((ic == 0xad) || (0xf5 <= ic )){
                                                PUT((JGETA >> 8) & CMASK);
                                                GET(ic); /* Get dummy */
                                                PUT(JGETA & CMASK);
                                                continue;
                                        }
#endif  /* RFC1468_MODE */
                                        /* Put JIS X 0208 character */
                                        PUT(ic & CMASK);
                                        GET(ic);
                                        PUT(ic & CMASK);
                                        continue;
                                } else {
                                        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 (ic == SS2) { /* Kana starts */
                        if ((int)ileft > 0) {
                                if (ISCS2(*ip)) {

#ifdef  RFC1468_MODE    /* Substitute JIS X 0208 for JIS X 0201 Katakana */
                                unsigned short  zenkaku;
                                        if (cset != CS_1) {
                                                if (oleft < SEQ_MBTOG0_O) {
                                                        UNGET();
                                                        errno = E2BIG;
                                                        retval =
                                                        (size_t)ERR_RETURN;
                                                        goto ret;
                                                }
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(F_X0208_83_90);
                                                cset = CS_1;
                                        }
                                        if (oleft < JISW1) {
                                                UNGET();
                                                errno = E2BIG;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
                                        GET(ic);
                                        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) {
                                                if (oleft < SEQ_SBTOG0) {
                                                        UNGET();
                                                        errno = E2BIG;
                                                        retval =
                                                        (size_t)ERR_RETURN;
                                                        goto ret;
                                                }
                                                PUT(ESC);
                                                PUT(SBTOG0_1);
                                                PUT(F_X0201_KN);
                                                cset = CS_2;
                                        }
                                        if (oleft < JISW2) {
                                                UNGET();
                                                errno = E2BIG;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
                                        /* Put Kana character */
                                        GET(ic);
                                        PUT(ic & CMASK);
#endif  /* RFC1468_MODE */
                                        continue;
                                } else {        /* 2nd byte is illegal */
                                        errno = EILSEQ;
                                        retval = (size_t)ERR_RETURN;
                                        goto ret;
                                }
                        } else {                /* input fragment of Kana */
                                UNGET();
                                errno = EINVAL;
                                retval = (size_t)ERR_RETURN;
                                goto ret;
                        }
                } else if (ic == SS3) { /* JISX0212 starts */
                        if (ileft >= EUCW3) {
                                if (ISCS3(*ip) && ISCS3(*(ip + 1))) {

/* ISO-2022-JP.RFC1468 or ISO-2022-JP.UIOSF */
#ifdef  RFC1468_MODE    /* Substitute JIS X 0208 "Geta" for JIS X 0212 */
                                        if (cset != CS_1) {
                                                if (oleft < SEQ_MBTOG0_O) {
                                                        UNGET();
                                                        errno = E2BIG;
                                                        retval =
                                                        (size_t)ERR_RETURN;
                                                        goto ret;
                                                }
                                                cset = CS_1;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(F_X0208_83_90);
                                        }
                                        if (oleft < JISW1) {
                                                UNGET();
                                                errno = E2BIG;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
                                        /* Put GETA (0x222e) */
                                        ic = (unsigned char)((JGETA >> 8) &
                                        CMASK);
                                        PUT(ic);
                                        ic = (unsigned char)(JGETA & CMASK);
                                        PUT(ic);
                                        GET(ic); /* dummy GET */
                                        GET(ic); /* dummy GET */
#else   /* ISO-2022-JP.UIOSF */
                                        if (cset != CS_3) {
                                                if (oleft < SEQ_MBTOG0) {
                                                        UNGET();
                                                        errno = E2BIG;
                                                        retval =
                                                        (size_t)ERR_RETURN;
                                                        goto ret;
                                                }
                                                cset = CS_3;
                                                PUT(ESC);
                                                PUT(MBTOG0_1);
                                                PUT(MBTOG0_2);
                                                PUT(F_X0212_90);
                                        }
                                        if (oleft < JISW3) {
                                                UNGET();
                                                errno = E2BIG;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
                                        /* Put JIS X 0212 character */
                                        GET(ic);
                                        PUT(ic & CMASK);
                                        GET(ic);
                                        PUT(ic & CMASK);
#endif  /* RFC1468_MODE */
                                        continue;
                                } else {
                                        errno = EILSEQ;
                                        retval = (size_t)ERR_RETURN;
                                        goto ret;
                                }
                        } else {        /* input fragment of JISX0212 */
                                UNGET();
                                errno = EINVAL;
                                retval = (size_t)ERR_RETURN;
                                goto ret;
                        }
                } else {
                        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);
}