/*
 * 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 particular file is to cover conversions from UTF-8 to various single
 * byte codesets.
 */


#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include "utf8_to_sb.h"



void *
_icv_open()
{
        ucs_state_t *cd = (ucs_state_t *)calloc(1, sizeof(ucs_state_t));
        if (cd == (ucs_state_t *)NULL) {
                errno = ENOMEM;
                return((void *)-1);
        }

        return((void *)cd);
}


void
_icv_close(ucs_state_t *cd)
{
        if (! cd)
                errno = EBADF;
        else
                free((void *)cd);
}


size_t
_icv_iconv(ucs_state_t *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;
        register int i, l, h;
        signed char sz;
        unsigned long u8;

        if (! cd) {
                errno = EBADF;
                return((size_t)-1);
        }

        if (!inbuf || !(*inbuf)) {
                cd->bom_written = false;
                return((size_t)0);
        }

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

        /* We skip any first signiture of UTF-8 */
        if (!cd->bom_written &&
                ((ibtail - ib) >= ICV_FETCH_UTF8_BOM_SIZE)) {
                for (u8 = 0, i = 0; i < ICV_FETCH_UTF8_BOM_SIZE; i++)
                        u8 = (u8 << 8) | ((uint_t)(*(ib + i)));
                if (u8 == ICV_BOM_IN_BIG_ENDIAN)
                        ib += ICV_FETCH_UTF8_BOM_SIZE;
        }
        cd->bom_written = true;

        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;
                }

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

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

                        u8 = 0;
                        for (i = 0; i < sz; i++) {
                                if (((unsigned int)*ib) < 0x80) {
                                        errno = EILSEQ;
                                        ret_val = (size_t)-1;
                                        goto illegal_char_err;
                                }
                                u8 = (u8 << 8) | ((unsigned int)*ib);
                                ib++;
                        }
                        if ((u8 & ICV_UTF8_REPRESENTATION_ffff_mask) ==
                            ICV_UTF8_REPRESENTATION_fffe ||
                            (u8 & ICV_UTF8_REPRESENTATION_ffff_mask) ==
                            ICV_UTF8_REPRESENTATION_ffff ||
                            u8 > ICV_UTF8_REPRESENTATION_10fffd ||
                            (u8 >= ICV_UTF8_REPRESENTATION_d800 &&
                            u8 <= ICV_UTF8_REPRESENTATION_dfff) ||
                            (u8 >= ICV_UTF8_REPRESENTATION_fdd0 &&
                            u8 <= ICV_UTF8_REPRESENTATION_fdef)) {
                                ib -= sz;
                                errno = EILSEQ;
                                ret_val = (size_t)-1;
                                goto illegal_char_err;
                        }

                        i = l = 0;
                        h = (sizeof(u8_sb_tbl) /
                             sizeof(to_sb_table_component_t)) - 1;
                        while (l <= h) {
                                i = (l + h) / 2;
                                if (u8_sb_tbl[i].u8 == u8)
                                        break;
                                else if (u8_sb_tbl[i].u8 < u8)
                                        l = i + 1;
                                else
                                        h = i - 1;
                        }

                        /*
                         * We just assume that either we found it or it is
                         * a non-identical character that we need to
                         * provide a replacement character.
                         */
                        if (u8_sb_tbl[i].u8 == u8) {
                                *ob++ = u8_sb_tbl[i].sb;
                        } else {
                                *ob++ = ICV_CHAR_ASCII_REPLACEMENT;
                                ret_val++;
                        }
                }
        }

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

        return(ret_val);
}