/*
 * 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-32, UTF-32BE, and
 * UTF-32LE to UCS-4, UCS-4BE, and UCS-4LE.
 */


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

/* We include the ucs_to_ucs4.h at the moment. */
#include "ucs_to_ucs4.h"


void *
_icv_open()
{
        ucs_ucs_state_t *cd;

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

#if defined(UTF_32BE)
        cd->input.little_endian = false;
        cd->input.bom_written = true;
#elif defined(UTF_32LE)
        cd->input.little_endian = true;
        cd->input.bom_written = true;
#elif defined(_LITTLE_ENDIAN)
        cd->input.little_endian = true;
#endif

#if defined(UCS_4BE)
        cd->output.little_endian = false;
        cd->output.bom_written = true;
#elif defined(UCS_4LE)
        cd->output.little_endian = true;
        cd->output.bom_written = true;
#elif defined(_LITTLE_ENDIAN)
        cd->output.little_endian = true;
#endif

        return((void *)cd);
}


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


size_t
_icv_iconv(ucs_ucs_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;
        uint_t u4;
        signed char obsz;
        int i;


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

        if (!inbuf || !(*inbuf)) {
#if defined(UTF_32)
                cd->input.bom_written = false;
#endif
#if defined(UCS_4)
                cd->output.bom_written = false;
#endif
                return((size_t)0);
        }

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

#if defined(UTF_32)
        if (! cd->input.bom_written) {
                if ((ibtail - ib) < ICV_FETCH_UCS4_SIZE) {
                        errno = EINVAL;
                        ret_val = (size_t)-1;
                        goto need_more_input_err;
                }

                for (u4 = 0, i = 0; i < ICV_FETCH_UCS4_SIZE; i++)
                        u4 = (u4 << 8) | ((uint_t)(*(ib + i)));

                if (u4 == ICV_BOM_IN_BIG_ENDIAN) {
                        ib += ICV_FETCH_UCS4_SIZE;
                        cd->input.little_endian = false;
                } else if (u4 == ICV_BOM_IN_LITTLE_ENDIAN_UCS4) {
                        ib += ICV_FETCH_UCS4_SIZE;
                        cd->input.little_endian = true;
                }
        }
        cd->input.bom_written = true;
#endif


        while (ib < ibtail) {
                if ((ibtail - ib) < ICV_FETCH_UCS4_SIZE) {
                        errno = EINVAL;
                        ret_val = (size_t)-1;
                        break;
                }

                u4 = 0;
                if (cd->input.little_endian) {
                        for (i = ICV_FETCH_UCS4_SIZE - 1; i >= 0; i--)
                                u4 = (u4 << 8) | ((uint_t)(*(ib + i)));
                } else {
                        for (i = 0; i < ICV_FETCH_UCS4_SIZE; i++)
                                u4 = (u4 << 8) | ((uint_t)(*(ib + i)));
                }

                if (u4 == 0x00fffe || u4 == 0x00ffff || u4 > 0x10ffff ||
                    (u4 >= 0x00d800 && u4 <= 0x00dfff)) {
                        errno = EILSEQ;
                        ret_val = (size_t)-1;
                        goto illegal_char_err;
                }

                obsz = (cd->output.bom_written) ? 2 : 4;
                if ((obtail - ob) < obsz) {
                        errno = E2BIG;
                        ret_val = (size_t)-1;
                        break;
                }

                if (cd->output.little_endian) {
                        if (! cd->output.bom_written) {
                                *ob++ = (uchar_t)0xff;
                                *ob++ = (uchar_t)0xfe;
                                *(ushort_t *)ob = (ushort_t)0;
                                ob += 2;
                                cd->output.bom_written = true;
                        }
                        *ob++ = (uchar_t)(u4 & 0xff);
                        *ob++ = (uchar_t)((u4 >> 8) & 0xff);
                        *ob++ = (uchar_t)((u4 >> 16) & 0xff);
                        *ob++ = (uchar_t)((u4 >> 24) & 0xff);
                } else {
                        if (! cd->output.bom_written) {
                                *(ushort_t *)ob = (ushort_t)0;
                                ob += 2;
                                *ob++ = (uchar_t)0xfe;
                                *ob++ = (uchar_t)0xff;
                                cd->output.bom_written = true;
                        }
                        *ob++ = (uchar_t)((u4 >> 24) & 0xff);
                        *ob++ = (uchar_t)((u4 >> 16) & 0xff);
                        *ob++ = (uchar_t)((u4 >> 8) & 0xff);
                        *ob++ = (uchar_t)(u4 & 0xff);
                }
                ib += ICV_FETCH_UCS4_SIZE;
        }

#if defined(UTF_32)
need_more_input_err:
#endif
illegal_char_err:
        *inbuf = (char *)ib;
        *inbufleft = ibtail - ib;
        *outbuf = (char *)ob;
        *outbufleft = obtail - ob;

        return(ret_val);
}