/*
 * Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
 * Copyright (C) 2010-2011 - DIGITEO - Allan CORNET
 *
 * This file must be used under the terms of the CeCILL.
 * This source file is licensed as described in the file COPYING, which
 * you should have received as part of this distribution.  The terms
 * are also available at
 * http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt
 *
 */
#include <string.h>
#include "utftolatin.h"
#include "MALLOC.h"
#ifdef _MSC_VER
#include "strdup_windows.h"
#endif
// =============================================================================
char *utftolatin(char *utfString)
{
    char *latinString = NULL;
    if (utfString)
    {
        size_t lenUtfString = strlen(utfString) + 1;
        latinString = (char*) CALLOC(lenUtfString, sizeof(char));

        if (latinString)
        {
            unsigned long ucs4 = 0;
            int c = 0, state = 0, octets = 0;
            char *t = NULL;

            ucs4 = 0;
            state = 0;
            octets = 0;

            t = latinString;
            *t = 0;

            while ((c = *(utfString++)) != 0)
            {
                switch (state)
                {
                    case 0: /* start of utf8 char */
                        if ((c & 0xfe) == 0xfc)
                        {
                            /* 6 octets */
                            ucs4 = (c & 0x01) << 30;
                            octets = 6;
                            state = 5;
                            /* look for 5 more */
                        }
                        else if ((c & 0xfc) == 0xf8)
                        {
                            /* 5 octets */
                            ucs4 = (c & 0x03) << 24;
                            octets = 5;
                            state = 4;
                        }
                        else if ((c & 0xf8) == 0xf0)
                        {
                            /* 4 octets */
                            ucs4 = (c & 0x07) << 18;
                            octets = 4;
                            state = 3;
                        }
                        else if ((c & 0xf0) == 0xe0)
                        {
                            /* 3 octets */
                            ucs4 = (c & 0x0f) << 12;
                            octets = 3;
                            state = 2;
                        }
                        else if ((c & 0xe0) == 0xc0)
                        {
                            /* 2 octets */
                            ucs4 = (c & 0x1f) << 6;
                            octets = 2;
                            state = 1;
                            /* look for 1 more */
                        }
                        else if ((c & 0x80) == 0x00)
                        {
                            /* 1 octet */
                            ucs4 = (c & 0x7f);
                            octets = 1;
                            state = 0;
                            /* we have a result */
                        }
                        else
                        {
                            /* error */
                            FREE(latinString);
                            return strdup(utfString);
                        }
                        break;
                    case 1:
                        if ((c & 0xc0) == 0x80)
                        {
                            ucs4 = ucs4 | (c & 0x3f);
                            if (ucs4 < 0x80 || ucs4 > 0x7ff)
                            {
                                ucs4 = 0xffffffff;
                            }
                        }
                        else
                        {
                            ucs4 = 0xffffffff;
                        }
                        state = 0;      /* we're done and have a result */
                        break;
                    case 2:
                        if ((c & 0xc0) == 0x80)
                        {
                            ucs4 = ucs4 | ((c & 0x3f) << 6);
                            state = 1;
                        }
                        else
                        {
                            ucs4 = 0xffffffff;
                            state = 0;
                        }
                        break;
                    case 3:
                        if ((c & 0xc0) == 0x80)
                        {
                            ucs4 = ucs4 | ((c & 0x3f) << 12);
                            state = 2;
                        }
                        else
                        {
                            ucs4 = 0xffffffff;
                            state = 0;
                        }
                        break;
                    case 4:
                        if ((c & 0xc0) == 0x80)
                        {
                            ucs4 = ucs4 | ((c & 0x3f) << 18);
                            state = 3;
                        }
                        else
                        {
                            ucs4 = 0xffffffff;
                            state = 0;
                        }
                        break;
                    case 5:
                        if ((c & 0xc0) == 0x80)
                        {
                            ucs4 = ucs4 | ((c & 0x3f) << 24);
                            state = 4;
                        }
                        else
                        {
                            ucs4 = 0xffffffff;
                            state = 0;
                        }
                        break;
                    default:        /* error, can't happen */
                    {
                        ucs4 = 0xffffffff;
                        state = 0;
                        break;
                    }
                }
                if (state == 0)
                {
                    switch (octets)
                    {
                        case 1:
                            if (ucs4 > 0x7f)
                            {
                                ucs4 = 0xffffffff;
                            }
                            break;
                        case 2:
                            if (ucs4 < 0x80 || ucs4 > 0x7ff)
                            {
                                ucs4 = 0xffffffff;
                            }
                            break;
                        case 3:
                            if (ucs4 < 0x800 || ucs4 > 0xffff)
                            {
                                ucs4 = 0xffffffff;
                            }
                            break;
                        case 4:
                            if (ucs4 < 0x10000 || ucs4 > 0x1fffff)
                            {
                                ucs4 = 0xffffffff;
                            }
                            break;
                        case 5:
                            if (ucs4 < 0x200000 || ucs4 > 0x3ffffff)
                            {
                                ucs4 = 0xffffffff;
                            }
                            break;
                        case 6:
                            if (ucs4 < 0x4000000 || ucs4 > 0x7fffffff)
                            {
                                ucs4 = 0xffffffff;
                            }
                            break;
                        default:
                            ucs4 = 0xffffffff;
                            break;
                    }

                    if (ucs4 != 0xffffffff)
                    {
                        *(t++) = (char)ucs4;
                    }
                }
            }
            *t = 0;
        }
    }
    return latinString;
}
// =============================================================================