/*
 * 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) 1998-1999 by Sun Microsystems, Inc.
 * All rights reserved.
 *
 * This program covers UTF-7 to UTF-8, UCS-2, and, UCS-4 code conversions.
 * UTF-7 described in RFC 2152.
 * We don't support any other UCS formats to and from UTF-7 unless there is
 * a significant requirement.
 */


#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/isa_defs.h>
#include "utf7_to_ucs.h"


void *
_icv_open()
{
        utf7_state_t *cd = (utf7_state_t *)calloc(1, sizeof(utf7_state_t));

        if (cd == (utf7_state_t *)NULL) {
                errno = ENOMEM;
                return((void *)-1);
        }

#if defined(_LITTLE_ENDIAN)
        cd->little_endian = true;
#endif

        return((void *)cd);
}


void
_icv_close(utf7_state_t *cd)
{
        if (! cd)
                errno = EBADF;
        else
                free((void *)cd);
}


size_t
_icv_iconv(utf7_state_t *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;

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

        if (!inbuf || !(*inbuf)) {
                /* We just ignore any remnant bits we so far accumulated. */
                cd->in_the_middle_of_utf7_sequence = false;
                cd->remnant = 0;
                cd->remnant_count = 0;
                cd->prevch = (uchar_t)'\0';

                return((size_t)0);
        }

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

        while (ib < ibtail) {
                uint_t temp_remnant;
                uint_t u4;
#if defined(UCS_2) || defined(UCS_4)
                signed char obsz;
#endif

                u4 = ICV_U7_UCS4_OUTOFUTF16;
                if (cd->in_the_middle_of_utf7_sequence) {
                        if (rmb64[*ib] >= 0) {
                                temp_remnant = (cd->remnant << 6) | rmb64[*ib];

                                switch (cd->remnant_count) {
                                case ICV_U7_ACTION_HARVEST1:
                                        u4 = (temp_remnant >> 2) & 0xffff;
                                        break;
                                case ICV_U7_ACTION_HARVEST2:
                                        u4 = (temp_remnant >> 4) & 0xffff;
                                        break;
                                case ICV_U7_ACTION_HARVEST3:
                                        u4 = temp_remnant & 0xffff;
                                        break;
                                }

                                if (u4 != ICV_U7_UCS4_OUTOFUTF16) {
                                        if (u4 == 0x00fffe || u4 == 0x00ffff ||
                                                (u4 >= 0x00d800 &&
                                                u4 <= 0x00dfff)) {
                                                errno = EILSEQ;
                                                ret_val = (size_t)-1;
                                                break;
                                        }
#if defined(UCS_2)
                                        CHECK_OUTBUF_SZ_AND_WRITE_U2;
#elif defined(UCS_4)
                                        CHECK_OUTBUF_SZ_AND_WRITE_U4;
#elif defined(UTF_8)
                                        CHECK_OUTBUF_SZ_AND_WRITE_U8_OR_EILSEQ;
#else
#error  "Fatal: One of UCS_2, UCS_4, or, UTF_8 is needed."
#endif
                                }

                                /* It's now safe to have the bits. */
                                cd->remnant = temp_remnant;
                                if (cd->remnant_count == ICV_U7_ACTION_HARVEST3)
                                        cd->remnant_count = ICV_U7_ACTION_START;
                                else
                                        cd->remnant_count++;
                        } else {
                                if (*ib == (uint_t)'-') {
                                        if (cd->prevch == '+')
                                                u4 = (uint_t)'+';
                                } else
                                        u4 = (uint_t)(*ib);

                                switch (cd->remnant_count) {
                                case ICV_U7_ACTION_START:
                                        /* (ICV_U7_ACTION_HARVEST3+1): */
                                        /* These are normal cases. */
                                        break;
                                case (ICV_U7_ACTION_HARVEST1+1):
                                        if (cd->remnant & 0x03) {
                                                errno = EILSEQ;
                                                ret_val = (size_t)-1;
                                                goto illegal_char_err;
                                        }
                                        break;
                                case (ICV_U7_ACTION_HARVEST2+1):
                                        if (cd->remnant & 0x0f) {
                                                errno = EILSEQ;
                                                ret_val = (size_t)-1;
                                                goto illegal_char_err;
                                        }
                                        break;
                                default:
                                        errno = EILSEQ;
                                        ret_val = (size_t)-1;
                                        goto illegal_char_err;
                                        break;
                                }

                                if (u4 != ICV_U7_UCS4_OUTOFUTF16) {
#if defined(UCS_2)
                                        CHECK_OUTBUF_SZ_AND_WRITE_U2;
#elif defined(UCS_4)
                                        CHECK_OUTBUF_SZ_AND_WRITE_U4;
#elif defined(UTF_8)
                                        if (ob >= obtail) {
                                                errno = E2BIG;
                                                ret_val = (size_t)-1;
                                                break;
                                        }
                                        *ob++ = (uchar_t)(u4 & 0x7f);
#else
#error  "Fatal: One of UCS_2, UCS_4, or, UTF_8 is needed."
#endif
                                }

                                cd->in_the_middle_of_utf7_sequence = false;
                                cd->remnant = 0;
                                cd->remnant_count = 0;
                        }
                } else {
                        if (*ib == '+') {
                                cd->in_the_middle_of_utf7_sequence = true;
                                cd->remnant = 0;
                                cd->remnant_count = 0;
                        } else {
#if defined(UCS_2)
                                u4 = (uint_t)*ib;
                                CHECK_OUTBUF_SZ_AND_WRITE_U2;
#elif defined(UCS_4)
                                u4 = (uint_t)*ib;
                                CHECK_OUTBUF_SZ_AND_WRITE_U4;
#elif defined(UTF_8)
                                if (ob >= obtail) {
                                        errno = E2BIG;
                                        ret_val = (size_t)-1;
                                        break;
                                }
                                *ob++ = *ib;
#else
#error  "Fatal: One of UCS_2, UCS_4, or, UTF_8 is needed."
#endif
                        }
                }
                cd->prevch = *ib++;
        }

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


        return(ret_val);
}