/*
 * 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>
#include "japanese.h"


/*
 * struct _cv_state; to keep status
 */
struct _icv_state {
	int	_st_cset;
	int	_st_cset_sav;
};

void *
_icv_open()
{
	struct _icv_state *st;

	if ((st = (struct _icv_state *)malloc(sizeof (struct _icv_state)))
									== NULL)
		return ((void *)ERR_RETURN);

	st->_st_cset = st->_st_cset_sav = CS_0;

	return (st);
}

void
_icv_close(struct _icv_state *st)
{
	free(st);
}

size_t
_icv_iconv(struct _icv_state *st, char **inbuf, size_t *inbytesleft,
				char **outbuf, size_t *outbytesleft)
{
	int cset;
	int stat = ST_INIT;
	unsigned char *op;
	char *ip, ic;
	size_t ileft, oleft;
	size_t retval;

	/*
	 * If inbuf and/or *inbuf are NULL, reset conversion descriptor
	 * and put escape sequence if needed.
	 */
	if ((inbuf == NULL) || (*inbuf == NULL)) {
		st->_st_cset_sav = st->_st_cset = CS_0;
		return ((size_t)0);
	}

	cset = st->_st_cset;

	ip = *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_INIT) {
			goto text;
		}

		/*
		 *  Half way of Kanji or ESC sequence
		 */
		if ((stat == ST_INCS1) || (stat == ST_INCS3)) {
			stat = ST_INIT;
			PUT(ic | CMSB);
			continue;
		} else if (stat == ST_ESC) {
			if (ic == MBTOG0_1) {
				if ((int)ileft > 0) {
					stat = ST_MBTOG0_1;
					continue;
				} else {
					UNGET();
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else if (ic == SBTOG0_1) {
				if ((int)ileft > 0) {
					stat = ST_SBTOG0;
					continue;
				} else {
					UNGET();
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else if (ic == X208REV_1) {
				if ((int)ileft > 0) {
					stat = ST_208REV_1;
					continue;
				} else {
					UNGET();
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else {
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (stat == ST_MBTOG0_1) {
			if ((ic == F_X0208_83_90) || (ic == F_X0208_78)) {
				stat = ST_INIT;
				st->_st_cset_sav = cset = CS_1;
				continue;
			} else if (ic == F_X0212_90) {
				stat = ST_INIT;
				st->_st_cset_sav = cset = CS_3;
				continue;
			} else if (ic == MBTOG0_2) {
				if ((int)ileft > 0) {
					stat = ST_MBTOG0_2;
					continue;
				} else {
					UNGET();
					UNGET();
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else {
				UNGET();
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (stat == ST_MBTOG0_2) {
			if ((ic == F_X0208_83_90) || (ic == F_X0208_78)) {
				stat = ST_INIT;
				st->_st_cset_sav = cset = CS_1;
				continue;
			} else if (ic == F_X0212_90) {
				stat = ST_INIT;
				st->_st_cset_sav = cset = CS_3;
				continue;
			} else {
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (stat == ST_SBTOG0) {
			if ((ic == F_ASCII) ||
				(ic == F_X0201_RM) ||
				(ic == F_ISO646)) {
				stat = ST_INIT;
				st->_st_cset_sav = cset = CS_0;
				continue;
			} else if (ic == F_X0201_KN) {
				cset = CS_2;
				stat = ST_INIT;
				continue;
			} else {
				UNGET();
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (stat == ST_208REV_1) {
			if (ic == X208REV_2) {
				if ((int)ileft > 0) {
					stat = ST_208REV_2;
					continue;
				} else {
					UNGET();
					UNGET();
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else {
				UNGET();
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (stat == ST_208REV_2) {
			if (ic == ESC) {
				if ((int)ileft > 0) {
					stat = ST_REV_AFT_ESC;
					continue;
				} else {
					UNGET();
					UNGET();
					UNGET();
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else {
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (stat == ST_REV_AFT_ESC) {
			if (ic == MBTOG0_1) {
				if ((int)ileft > 0) {
					stat = ST_REV_AFT_MBTOG0_1;
					continue;
				} else {
					UNGET();
					UNGET();
					UNGET();
					UNGET();
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else {
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (stat == ST_REV_AFT_MBTOG0_1) {
			if (ic == F_X0208_83_90) {
				stat = ST_INIT;
				st->_st_cset_sav = cset = CS_1;
				continue;
			} else if (ic == MBTOG0_2) {
				if ((int)ileft > 0) {
					stat = ST_REV_AFT_MBTOG0_2;
					continue;
				} else {
					UNGET();
					UNGET();
					UNGET();
					UNGET();
					UNGET();
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else {
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (stat == ST_REV_AFT_MBTOG0_2) {
			if (ic == F_X0208_83_90) {
				stat = ST_INIT;
				st->_st_cset_sav = cset = CS_1;
				continue;
			} else {
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				UNGET();
				errno = EILSEQ;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		}
text:
		/*
		 * Break through chars or ESC sequence
		 */
		if (ic == ESC) {
			if ((int)ileft > 0) {
				stat = ST_ESC;
				continue;
			} else {
				UNGET();
				errno = EINVAL;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
		} else if (ic == SO) {
			cset = CS_2;
			stat = ST_INIT;
			continue;
		} else if (ic == SI) {
			cset = st->_st_cset_sav;
			stat = ST_INIT;
			continue;
		}
		if (!(ic & CMSB)) {
			if (cset == CS_0) {
				if (oleft < EUCW0) {
					UNGET();
					errno = E2BIG;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
				PUT(ic);
				continue;
			} else if (cset == CS_2) {
				if (oleft < (EUCW2 + SEQ_SS)) {
					UNGET();
					errno = E2BIG;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
				PUT(SS2);
				PUT(ic | CMSB);
				continue;
			} else if (cset == CS_3) {
				if ((int)ileft > 0) {
					if (oleft < (EUCW3 + SEQ_SS)) {
						UNGET();
						errno = E2BIG;
						retval = (size_t)ERR_RETURN;
						goto ret;
					}
					stat = ST_INCS3;
					PUT(SS3);
					PUT(ic | CMSB);
					continue;
				} else {
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			} else {
				if ((int)ileft > 0) {
					if (oleft < EUCW1) {
						UNGET();
						errno = E2BIG;
						retval = (size_t)ERR_RETURN;
						goto ret;
					}
					stat = ST_INCS1;
					PUT(ic | CMSB);
					continue;
				} else {
					UNGET();
					errno = EINVAL;
					retval = (size_t)ERR_RETURN;
					goto ret;
				}
			}
		} else {
			if (oleft < UNKNOWNW) {
				UNGET();
				errno = E2BIG;
				retval = (size_t)ERR_RETURN;
				goto ret;
			}
			PUT(ic);
			continue;
		}
	}
	retval = ileft;
ret:
	*inbuf = ip;
	*inbytesleft = ileft;
	*outbuf = (char *)op;
	*outbytesleft = oleft;
	st->_st_cset = cset;

	return (retval);
}