/*
 * 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 (c) 1996 by Sun Microsystems, Inc.
 */


#include <stdlib.h>
#include <errno.h>
#include <widec.h>
#include "common_han.h"
#include "euc_utf_api.h"

#define ESC             0x1B
#define SO              0x0E
#define SI              0x0F

typedef struct __conv_desc {
        enum { NOT_DEFINED_YET, KSC5601 }       designator;
        enum { ASCII, HANGUL }  state;
} _conv_desc;

/****  _ I C V _ O P E N  ****/

void* _icv_open()
{
        _conv_desc* cd = (_conv_desc*)malloc(sizeof(_conv_desc));

        if (cd == (_conv_desc*)NULL)
        {
                errno = ENOMEM;
                return((void*)-1);
        }

        cd->designator = NOT_DEFINED_YET;
        cd->state = ASCII;

        return((void*)cd);
}  /* end of int _icv_open(). */


/****  _ I C V _ C L O S E  ****/

void _icv_close(_conv_desc* cd)
{
        if (!cd)
                errno = EBADF;
        else
                free((void*)cd);
}  /* end of void _icv_close(_conv_desc*). */


/****  _ I C V _ I C O N V  ****/

size_t _icv_iconv(_conv_desc* cd, char** inbuf, size_t* inbufleft,
                        char** outbuf, size_t* outbufleft)
{
        size_t          ret_val = 0;
        unsigned char*  ib;
        unsigned char*  ob;
        unsigned char*  ibtail;
        unsigned char*  obtail;

        if (!cd)
        {
                errno = EBADF;
                return((size_t)-1);
        }

        if (!inbuf || !(*inbuf))
        {
                cd->designator = NOT_DEFINED_YET;
                cd->state = ASCII;
                return((size_t)0);
        }

        ib = (unsigned char*)*inbuf;
        ob = (unsigned char*)*outbuf;
        ibtail = ib + *inbufleft;
        obtail = ob + *outbufleft;

        while (ib < ibtail)
        {
                if (cd->designator == KSC5601)
                {
                        hcode_type euc_code, utf_code;

                        if (*ib == SI)
                        {
                                cd->state = ASCII;
                                ib++;
                                continue;
                        }
                        else if (*ib == SO)
                        {
                                cd->state = HANGUL;
                                ib++;
                                continue;
                        }
                        else if ((*ib == ' ' && cd->state == HANGUL) ||
                                 cd->state == ASCII)
                        {
                                if (ob >= obtail)
                                {
                                        errno = E2BIG;
                                        ret_val = (size_t)-1;
                                        break;
                                }
                                *ob++ = *ib++;
                                continue;
                        }

                        /* Pure KS C 5601 Wansung code */
                        if ((ibtail - ib) < 2)
                        {
                                errno = EINVAL;
                                ret_val = (size_t)-1;
                                break;
                        }

                        if (*ib < 0x21 || *ib > 0x7E || *(ib + 1) < 0x21 ||
                            *(ib + 1) == 0x7F)
                        {
                                errno = EILSEQ;
                                ret_val = (size_t)-1;
                                break;
                        }

                        euc_code.code = 0;
                        euc_code.byte.byte3 = *ib;
                        euc_code.byte.byte4 = *(ib + 1);
                        euc_code.wansung.msb1 = 1;
                        euc_code.wansung.msb2 = 1;

                        utf_code = _wansung_to_utf8(euc_code);

                        if (utf_code.code != 0)
                        {
                                if ((obtail - ob) < 3)
                                        {
                                                errno = E2BIG;
                                                ret_val = (size_t)-1;
                                                break;
                                        }
                                /* UTF8 code from 2 bytes is always 3 bytes */
                                *ob++ = (char)utf_code.byte.byte2;
                                *ob++ = (char)utf_code.byte.byte3;
                                *ob++ = (char)utf_code.byte.byte4;
                        }
                        else  /* FAILED - this means input char isn't belong to
                               *          input codeset. */
                        {
                                errno = EILSEQ;
                                ret_val = (size_t)-1;
                                break;
                        }
                        ib += 2;

                }
                else
                {
                        if (*ib == ESC)
                        {
                                if ((ibtail - ib) < 4)
                                {
                                        errno = EINVAL;
                                        ret_val = (size_t)-1;
                                        break;
                                }

                                if (*(ib + 1) == '$' && *(ib + 2) == ')' &&
                                    *(ib + 3) == 'C')
                                {
                                        cd->designator = KSC5601;
                                        ib += 4;
                                        continue;
                                }
                        }

                        if (ob >= obtail)
                        {
                                errno = E2BIG;
                                ret_val = (size_t)-1;
                                break;
                        }
                        *ob++ = *ib++;
                }
        }

        *inbuf = (char*)ib;
        *inbufleft = ibtail - ib;
        *outbuf = (char*)ob;
        *outbufleft = obtail - ob;

        return(ret_val);
}  /* end of size_t _icv_iconv(_conv_desc*, char**, size_t*, char**, size_t*).*/