/*
 * 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*).*/