/*
 * 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>
#define JFP_ICONV_STATELESS
#include "japanese.h"

static unsigned short lookuptbl(unsigned short);

void *
_icv_open(void)
{
        return (_icv_open_stateless());
}

void
_icv_close(void *cd)
{
        _icv_close_stateless(cd);
        return;
}

size_t
_icv_iconv(void *cd, char **inbuf, size_t *inbytesleft,
                                char **outbuf, size_t *outbytesleft)
{
        int                             stat;
        unsigned char   *ip, ic, *op;
        size_t                  ileft, oleft;
        size_t                  retval;

        stat = ST_INIT;

        /*
         * If inbuf and/or *inbuf are NULL, reset conversion descriptor
         * and put escape sequence if needed.
         */
        if ((inbuf == NULL) || (*inbuf == NULL)) {
                /* nothing to do here for this module */
                return ((size_t)0);
        }

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

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

        while ((int)ileft > 0) {
                GET(ic);
                if (stat == ST_INCS2) {
                        PUT(ic);
                        stat = ST_INIT;
                        continue;
                }
                if (ISASC((int)ic)) {           /* ASCII */
                        if (oleft < SJISW0) {
                                UNGET();
                                errno = E2BIG;
                                retval = (size_t)ERR_RETURN;
                                goto ret;
                        }
                        PUT(ic);
                        continue;
                }
                if (ISCS1(ic)) {                        /* Kanji starts */
                        if ((int)ileft > 0) {
                                if (ISCS1(*ip)) {
                                        int even_ku;
                                        if (oleft < SJISW1) {
                                                UNGET();
                                                errno = E2BIG;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
                                        ic &= 0x7f;
                                        PUT(jis208tosj1[ic]);
                                        if ((ic % 2) == 0)
                                                even_ku = TRUE;
                                        else
                                                even_ku = FALSE;
                                        GET(ic);
                                        ic &= 0x7f;
                                        if (even_ku)
                                                ic += 0x80;
                                        PUT(jistosj2[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 (ic == SS2) { /* Kana starts */
                        if ((int)ileft > 0) {
                                if (ISCS2(*ip)) {
                                        if (oleft < SJISW2) {
                                                UNGET();
                                                errno = E2BIG;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
                                        stat = ST_INCS2;
                                        continue;
                                } else {        /* 2nd byte is illegal */
                                        UNGET();
                                        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) { /* CS_3 Kanji starts */
                        unsigned short dest;
                        if (ileft >= EUCW3) {
                                if (ISCS3(*ip) && ISCS3(*(ip + 1))) {
                                        if (oleft < SJISW1) {
                                                UNGET();
                                                errno = E2BIG;
                                                retval = (size_t)ERR_RETURN;
                                                goto ret;
                                        }
                                        if (*ip < 0xf5) { /* check IBM area */
                                                GET(ic);
                                                dest = (ic << 8);
                                                GET(ic);
                                                dest += ic;
                                                dest = lookuptbl(dest);
                                                if (dest == 0xffff) {
                                                        /*
                                                         * Illegal code points
                                                         * in G3 plane.
                                                         */
                                                        UNGET();
                                                        UNGET();
                                                        errno = E2BIG;
                                                        retval =
                                                        (size_t)ERR_RETURN;
                                                        goto ret;
                                                } else {
                                                        PUT((dest >> 8) &
                                                        0xff);
                                                        PUT(dest & 0xff);
                                                }
                                                continue;
                                        } else {
                                                unsigned char c1, c2;

                                                GET(c1);
                                                GET(c2);
                                                c1 &= 0x7f;
                                                c2 &= 0x7f;
                                                if ((c1 % 2) == 0)
                                                        c2 += 0x80;
                                                c1 = jis212tosj1[c1];
                                                c2 = jistosj2[c2];
                                                if ((c1 != 0xff) &&
                                                        (c2 != 0xff)) {
                                                        PUT(c1);
                                                        PUT(c2);
                                                        continue;
                                                }
                                                PUT((PGETA >> 8) & 0xff);
                                                PUT(PGETA & 0xff);
                                                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 = (char *)op;
        *outbytesleft = oleft;

        return (retval);
}

/*
 * lookuptbl()
 * Return the index number if its index-ed number
 * is the same as dest value.
 */
static unsigned short
lookuptbl(unsigned short dest)
{
        unsigned short tmp;
        int i;
        int sz = (sizeof (sjtoibmext) / sizeof (sjtoibmext[0]));

        for (i = 0; i < sz; i++) {
                tmp = sjtoibmext[i];
                if (tmp == dest)
                        return ((i + 0xfa40 + ((i / 0xc0) * 0x40)));
        }
        return (PGETA);
}