/*
 * 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) 1995 by Sun Microsystems, Inc.
 * All Rights Reserved.
 */


#include <errno.h>
#include "ktable.h"
#include "hangulcode.h"

static unsigned short _wansung_to_johap92(unsigned short code);

/****  _ 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
                {
                        unsigned short code;

                        if ((ibtail - ib) < 2)
                        {
                                errno = EINVAL;
                                ret_val = (size_t)-1;
                                break;
                        }

                        if ((obtail - ob) < 2)
                        {
                                errno = E2BIG;
                                ret_val = (size_t)-1;
                                break;
                        }

                        code = _wansung_to_johap92((unsigned short)(*ib)<<8 |
                                        (unsigned short)(*(ib + 1)));
                        if (code != FAILED && code != ILLEGAL_SEQ)
                        {
                                *ob++ = (unsigned char)(code >> 8);
                                *ob++ = (unsigned char)(code & 0xFF);
                        }
                        else
                        {
                                *ob++ = NON_IDENTICAL;
                                *ob++ = NON_IDENTICAL;
                        }
                        ib += 2;
                }
        }

        *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*).*/


/**** _ W A N S U N G _ T O _ J O H A P 9 2 ****/

static unsigned short _wansung_to_johap92(unsigned short code)
{
        register unsigned short jc, jc2;
        register short          h, i, l;
        short                   ci, v, cf;
        short                   disp;
        long                    cfbit;

        if ((unsigned short)(code & 0xFF) < 0xA1)
                return(ILLEGAL_SEQ);

        if (code >= 0xB0A1 && code <= 0xC8FE)  /* Hangul */
        {
                for (h = CI_CNT, l = 0; ; )
                {
                        ci = (l + h) / 2;
                        if (l >= h)
                                break;
                        if (code < cmp_srchtbl[ci][0])
                                h = ci - 1;
                        else if (code < cmp_srchtbl[ci + 1][0])
                                break;
                        else
                                l = ci + 1;
                }

                for (v = 1; ; )
                {
                        if (code < cmp_srchtbl[ci][v])
                        {
                                while (!cmp_srchtbl[ci][--v])
                                        ;
                                break;
                        }
                        else if (v == V_CNT)
                                break;
                        v++;
                }

                disp = code - cmp_srchtbl[ci][v];
                if (((short)(cmp_srchtbl[ci][v] & BYTE_MASK) + disp) > 0xfe)
                        disp -= SKIP;

                for (cfbit = cmp_bitmap[ci][v], i = -1, cf = -1; i < disp; cf++)
                {
                        if (cfbit & BIT_MASK)
                                i++;
                        cfbit >>= 1;
                }

                if (cf == -1)
                        return(FAILED);

                code = ci + 2;
                code = (code << 5) | (v + (v + 1) / 6 * 2 + 3);
                return((code << 5) | (cf + cf / 18) | 0x8000);
        }
        else if (code >= 0xA1A1 && code <= 0xACFE)  /* Special symbols */
        {
                jc = (((unsigned short)(code - 0xA100) >> 1) + 0xD900) & 0xFF00;
                jc2 = code & 0xFF;
                if ((unsigned short)(code >> 8) % 2)
                        return(jc | (jc2 - ((jc2 > 0xEE) ? 0x5E : 0x70)));
                return(jc | jc2);
        }
        else if (code >= 0xCAA1 && code <= 0xFDFE)  /* Hanja */
        {
                jc = (((unsigned short)(code - 0xCA00) >> 1) + 0xE000) & 0xFF00;
                jc2 = code & 0xFF;
                if ((unsigned short)(code >> 8) % 2)
                        return(jc | jc2);
                return(jc | (jc2 - ((jc2 > 0xEE) ? 0x5E : 0x70)));
        }
        else if ((code >= 0xC9A1 && code <= 0xC9FE) ||
                 (code >= 0xFEA1 && code <= 0xFEFE))  /* User-definable area */
        {
                if ((code & 0xFF00) == 0xFE00)
                        return(0xD800 | (code & 0xFF));
                code = code & 0xFF;
                return(0xD800 | (code - ((code > 0xEE) ? 0x5E : 0x70)));
        }

        return(FAILED);
}  /* end of static unsigned short _wansung_to_johap92(unsigned short). */