/*
 * 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 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * This is for UTF-8 to UTF-8 code conversion; it simply passes through
 * all things with UTF-8 byte sequence checking to screen out any illegal
 * and thus potentially harmful bytes.
 */


#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/isa_defs.h>
#include "common_defs.h"


void *
_icv_open()
{
        return((void *)MAGIC_NUMBER);
}


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


size_t
_icv_iconv(int *cd, char **inbuf, size_t *inbufleft, char **outbuf,
                size_t *outbufleft)
{
        size_t ret_val = 0;
        uchar_t *ib;
        uchar_t *ob;
        uchar_t *ibtail;
        uchar_t *obtail;
        uchar_t *ib_copy;
        uint_t u4;
        uint_t first_byte;
        signed char sz;
        signed char obsz;

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

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

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

        while (ib < ibtail) {
                sz = number_of_bytes_in_utf8_char[*ib];
                if (sz == ICV_TYPE_ILLEGAL_CHAR) {
                        errno = EILSEQ;
                        ret_val = (size_t)-1;
                        break;
                }
                obsz = sz;

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

                ib_copy = ib;
                first_byte = *ib_copy++;
                u4 = first_byte & (uint_t)masks_tbl[sz];
                for (; sz > 1; sz--) {
                        if (first_byte) {
                                if (((uchar_t)*ib_copy) <
                                        valid_min_2nd_byte[first_byte] ||
                                    ((uchar_t)*ib_copy) >
                                        valid_max_2nd_byte[first_byte]) {
                                        errno = EILSEQ;
                                        ret_val = (size_t)-1;
                                        goto ILLEGAL_CHAR_ERR;
                                }
                                first_byte = 0;
                        } else if (((uint_t)*ib_copy) < 0x80 ||
                                   ((uint_t)*ib_copy) > 0xbf) {
                                errno = EILSEQ;
                                ret_val = (size_t)-1;
                                goto ILLEGAL_CHAR_ERR;
                        }
                        u4 = (u4 << ICV_UTF8_BIT_SHIFT) |
                                (((uint_t)*ib_copy) & ICV_UTF8_BIT_MASK);
                        ib_copy++;
                }

                /*
                 * Check some more illegal characters and noncharacters from
                 * the input buffer. Surrogate pairs (U+D800 - U+DFFF) are
                 * checked at the above for loop.
                 */
                if ((u4 & 0xffff) == 0x00fffe || (u4 & 0xffff) == 0x00ffff ||
                    (u4 >= 0x00fdd0 && u4 <= 0x00fdef) || u4 > 0x10fffd) {
                        errno = EILSEQ;
                        ret_val = (size_t)-1;
                        goto ILLEGAL_CHAR_ERR;
                }

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

                for (; obsz >= 1; obsz--)
                        *ob++ = *ib++;
        }

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

        return(ret_val);
}