/*
 * 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 UCS-4, UCS-4BE, UCS-4LE,
 * UTF-32, UTF-32BE, and UTF-32LE to various other UCS formats, especially,
 * UCS-2, UCS-2BE, UCS-2LE, UTF-16, UTF-16BE, and UTF-16LE.
 */


#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/isa_defs.h>
#include "ucs4_to_ucs.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(UCS_4BE) || defined(UTF_32BE)
        cd->input.little_endian = false;
        cd->input.bom_written = true;
#elif defined(UCS_4LE) || 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(UTF_16BE) || defined(UCS_2BE)
        cd->output.little_endian = false;
        cd->output.bom_written = true;
#elif defined(UTF_16LE) || defined(UCS_2LE)
        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;
        uint_t u4_2;
        signed char obsz;
        int i;


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

        if (!inbuf || !(*inbuf)) {
#if defined(UCS_4) || defined(UTF_32)
                cd->input.bom_written = false;
#endif
#if defined(UCS_2) || defined(UTF_16)
                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(UCS_4) || 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 = u4_2 = 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 ||
#if defined(UTF_32) || defined(UTF_32BE) || defined(UTF_32LE)
                    u4 > 0x10ffff ||
#elif defined(UCS_4) || defined(UCS_4BE) || defined(UCS_4LE)
                    u4 > 0x7fffffff ||
#endif
                    (u4 >= 0x00d800 && u4 <= 0x00dfff)) {
                        errno = EILSEQ;
                        ret_val = (size_t)-1;
                        goto illegal_char_err;
                }

                obsz = (cd->output.bom_written) ? 2 : 4;
#if defined(UCS_2) || defined(UCS_2BE) || defined(UCS_2LE)
                if (u4 > 0x00ffff) {
                        u4 = ICV_CHAR_UCS2_REPLACEMENT;
                        ret_val++;
                }
#elif defined(UTF_16) || defined(UTF_16BE) || defined(UTF_16LE)
                if (u4 > 0x10ffff) {
                        u4 = ICV_CHAR_UCS2_REPLACEMENT;
                        ret_val++;
                } else if (u4 > 0x00ffff) {
                        u4_2 = ((u4 - 0x010000) % 0x400) + 0x00dc00;
                        u4   = ((u4 - 0x010000) / 0x400) + 0x00d800;
                        obsz += 2;
                }
#elif defined(UCS_4) || defined(UCS_4BE) || defined(UCS_4LE) || \
        defined(UTF_32) || defined(UTF_32BE) || defined(UTF_32LE)
                /*
                 * We do nothing here since these if expressions
                 * are only for preparing for output buffer;
                 * macros such as UCS_4/UCS_4BE/UCS_4LE and
                 * UTF_32/UTF_32BE/UTF_32LE are only for input.
                 */
#else
#error  "Fatal: one of the UCS macros need to be defined."
#endif
                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;
                                cd->output.bom_written = true;
                        }
                        *ob++ = (uchar_t)(u4 & 0xff);
                        *ob++ = (uchar_t)((u4 >> 8) & 0xff);
#if defined(UTF_16) || defined(UTF_16BE) || defined(UTF_16LE)
                        if (u4_2) {
                                *ob++ = (uchar_t)(u4_2 & 0xff);
                                *ob++ = (uchar_t)((u4_2 >> 8) & 0xff);
                        }
#endif
                } else {
                        if (! cd->output.bom_written) {
                                *ob++ = (uchar_t)0xfe;
                                *ob++ = (uchar_t)0xff;
                                cd->output.bom_written = true;
                        }
                        *ob++ = (uchar_t)((u4 >> 8) & 0xff);
                        *ob++ = (uchar_t)(u4 & 0xff);
#if defined(UTF_16) || defined(UTF_16BE) || defined(UTF_16LE)
                        if (u4_2) {
                                *ob++ = (uchar_t)((u4_2 >> 8) & 0xff);
                                *ob++ = (uchar_t)(u4_2 & 0xff);
                        }
#endif
                }
                ib += ICV_FETCH_UCS4_SIZE;
        }

#if defined(UCS_4) || 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);
}