/*
 * 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) 2008, by Sun Microsystems, Inc.
 * All rights reserved.
 */

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>
#define __NEED_VISCII_2_UNI__
#include <unicode_viscii.h>     /* Unicode to viscii mapping table */
#include "common_defs.h"


typedef struct _icv_state {
    char        keepc[4];       /* maximum # byte of UCS code */
    int _errno;         /* internal errno */
} _iconv_st;



/*
 * Open; called from iconv_open()
 */
void *
_icv_open()
{
    _iconv_st *st;

    if ((st = (_iconv_st *)malloc(sizeof(_iconv_st))) == NULL) {
        errno = ENOMEM;
        return ((void *) -1);
    }

    st->_errno = 0;
    return ((void *) st);
}


/*
 * Close; called from iconv_close()
 */
void
_icv_close(_iconv_st *st)
{
    if (!st)
        errno = EBADF;
    else
        free(st);
}


/*
 * Actual conversion; called from iconv()
 */
size_t
_icv_iconv(_iconv_st *st, char **inbuf, size_t *inbytesleft,
                                char **outbuf, size_t *outbytesleft)
{

#ifdef DEBUG
    fprintf(stderr, "==========    iconv(): viscii -->UTF-8   ==========\n");
#endif
    if (st == NULL) {
        errno = EBADF;
        return ((size_t) -1);
    }

    if (inbuf == NULL || *inbuf == NULL) { /* Reset request. */
        st->_errno = 0;
        return ((size_t) 0);
    }

    st->_errno = 0;     /* reset internal errno */
    errno = 0;          /* reset external errno */

    /* convert viscii encoding to UTF-8 */
    while (*inbytesleft > 0 && *outbytesleft > 0) {
        unsigned long uni = 0;

        viscii_2_uni((unsigned char*)*inbuf, &uni);
        if (uni < 0x80) {
            *(*outbuf)++ = (char)uni;
            (*outbytesleft) -= 1;
        } else if (uni >= 0x0080 && uni <= 0x07ff) {
            if (*outbytesleft < 2 ) {
                errno = E2BIG;
                return((size_t)-1);
            }
            *(*outbuf)++ = (char)((uni >> 6) & 0x1f) | 0xc0;
            *(*outbuf)++ = (char)(uni & 0x3f) | 0x80;
            *outbytesleft -= 2;
        } else if (uni >= 0x0800 && uni <= 0xffff) {
            if (*outbytesleft < 3) {
                errno = E2BIG;
                return((size_t)-1);
            }
            *(*outbuf)++ = (char)((uni >> 12) & 0xf) | 0xe0;
            *(*outbuf)++ = (char)((uni >>6) & 0x3f) | 0x80;
            *(*outbuf)++ = (char)(uni & 0x3f) | 0x80;
            *outbytesleft -= 3;
        }

        (*inbuf)++;
        (*inbytesleft)--;

    }

    if ( *inbytesleft > 0 && *outbytesleft <= 0 ) {
         errno = E2BIG;
         return ((size_t)-1);
    }

    return ((size_t)(*inbytesleft));
}