/*
 * 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 <errno.h>
#include <widec.h>
#include "common_def.h"
#include "common_thai.h"
#include "utf_euc_api.h"

#include "common_defs.h"
/****  _ I C V _ O P E N  ****/

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


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

void _icv_close(int* cd)
{
        if (!cd || cd != (int*)MAGIC_NUMBER)
                errno = EBADF;
}  /* end of void _icv_close(int*). */


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

size_t _icv_iconv(int* 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 || cd != (int*)MAGIC_NUMBER)
        {
                errno = EBADF;
                return((size_t)-1);
        }

        if (!inbuf || !(*inbuf))
                return((size_t)0);

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

        while (ib < ibtail)
        {
                if (!(*ib & 0x80))              /* 7 bits */
                {
                        if (ob >= obtail)
                        {
                                errno = E2BIG;
                                ret_val = (size_t)-1;
                                break;
                        }
                        *ob++ = *ib++;
                }
                else if ((*ib & 0xF0) == 0xE0)  /* 16 bits */
                {
                        hcode_type utf8_code, euc_code;

                        if ((ibtail - ib) < 3)
                        {
                                errno = EINVAL;
                                ret_val = (size_t)-1;
                                break;
                        }

            /* UNICODE 3.2 :eliminate non-secure UTF-8 sequence  */
                        if (*(ib+1)<valid_min_2nd_byte[*ib] || *(ib+1)>valid_max_2nd_byte[*ib])
                        {
                                errno = EILSEQ;
                                ret_val = (size_t)-1;
                                break;
                        }
                        else if ((*(ib+2)&0xC0)^0x80)
                        {
                                errno = EILSEQ;
                                ret_val = (size_t)-1;
                                break;
                        }
                        else if (*ib==0xEF && *(ib+1)==0xBF && (*(ib+2)==0xBF || *(ib+2)==0xBE))
                        { /*U+FFFE , U+FFFF*/
                                errno = EILSEQ;
                                ret_val = (size_t)-1;
                                break;
                        }

                        utf8_code.byte.byte1 = 0;
                        utf8_code.byte.byte2 = *ib;
                        utf8_code.byte.byte3 = *(ib + 1);
                        utf8_code.byte.byte4 = *(ib + 2);

                        euc_code = _utf8_to_eucTH(utf8_code);

                        if (euc_code.code != 0) {
                                /* If find something -> EUC code */
                                *ob++ = euc_code.byte.byte4;
                        }
                        else
                        {
                                /* Let's assume the code is non-identical. */
                                if ((obtail - ob) < 1)
                                {
                                        errno = E2BIG;
                                        ret_val = (size_t)-1;
                                        break;
                                }
                                *ob++ = NON_IDENTICAL;
                                ret_val += 1;
                        }
                        ib += 3;
                }
                else  /* 11, 21, 26 & 31 bits codes won't be able to convert. */
                {
                        short int offset;

                        errno = 0;
                        offset = number_of_bytes_in_utf8_char[*ib];
                        if (offset == ICV_TYPE_ILLEGAL_CHAR )
                        {
                                errno = EILSEQ;
                        }
                        else if (ibtail-ib < offset)
                        {
                                errno = EINVAL;
                        }
                        else if (*(ib+1)<valid_min_2nd_byte[*ib] || *(ib+1)>valid_max_2nd_byte[*ib])
                        {
                                errno = EILSEQ;
                        }
                        else /* check the remaining byte [0x80, 0xBF] */
                        {
                                int i;
                                for(i=2;i<offset;i++)
                                {
                                        if ((*(ib+i) & 0xC0) ^ 0x80)
                                        {
                                                errno = EILSEQ;
                                                break;
                                        }
                                }
                        }
                        if(errno)
                        {
                                ret_val = (size_t)-1;
                                break;
                        }

                        ib += offset;

                        /* Let's assume the code is non-identical. */
                        offset = (offset > 2) ? 2 : 1;
                        if ((obtail - ob) < offset)
                        {
                                errno = E2BIG;
                                ret_val = (size_t)-1;
                                break;
                        }
                        *ob++ = NON_IDENTICAL;
                        if (offset > 1)
                                *ob++ = NON_IDENTICAL;
                        ret_val += offset;
                }
        }

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

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