/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/***************************************************************************

 *   Copyright (C) 2006 by Jocelyn Merand                                  *

 *   joc.mer@gmail.com                                                     *

 *                                                                         *

 * THE BSD LICENSE

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 * notice, this list of conditions and the following disclaimer.

 *

 * - Redistributions in binary form must reproduce the above copyright

 * notice, this list of conditions and the following disclaimer in the

 * documentation and/or other materials provided with the

 * distribution.

 *

 * - Neither the name of the WiseGuys Internet B.V. nor the names of

 * its contributors may be used to endorse or promote products derived

 * from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

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 ***************************************************************************/

#include "utf8misc.h"

/* #include <stdio.h> */

/**

 * These variables are used in character processing functions

 * These have been added to manage utf-8 symbols, particularly escape chars

 */

#ifndef _UTF8_

#define _UTF8_

#endif

#ifdef _UTF8_

#define ESCAPE_MASK 0x80

#define WEIGHT_MASK 0xF0

#else

#define ESCAPE_MASK 0xFF

#define WEIGHT_MASK 0x00

#endif

const char *utf8_next_char(const char *str)

{

    if (*str & ESCAPE_MASK)

    {

        /* 

         * if the first bit of the current char is 1 then *str is an escape

         * character

         */

        unsigned char escape_char = ((*str & WEIGHT_MASK) << 1);

        /* 

         * and we use it to count (by bit translation) following characters

         * (only the weightest part)

         */

        while (escape_char & ESCAPE_MASK && *str)

        {

            /* 

             * every step, we move the byte of 1 bit left, when first bit is 0,

             * it's finished

             */

            escape_char = escape_char << 1;

            ++str;

        }

    }

    if (*str)

    {

        /* 

         * finally, if we are not on the \0 character, we jump to the next

         * character

         */

        ++str;

    }

    return str;

}

int utf8_charcopy(const char *str, char *dest)

{

    int pointer = 0;

    /* if the first bit of the current char is 1 */

    if (str[pointer] & ESCAPE_MASK)

    {

        /* 

         * then str[pointer] is an escape character and we use it to count

         * following characters (only the weightest part)

         */

        unsigned char escape_char = ((str[pointer] & WEIGHT_MASK) << 1);

        /* 

         * every step, we move the byte of 1 bit left, when first bit is 0,

         * it's finished

         */

        while (escape_char & ESCAPE_MASK && str[pointer])

        {

            dest[pointer] = str[pointer];

            escape_char = escape_char << 1;

            ++pointer;

        }

    }

    if (str[pointer])

    {

        dest[pointer] = str[pointer];

        ++pointer;

    }

    return pointer;

}

int utf8_issame(char *lex, char *key, int len)

{

    /* printf("[%s] prefix of [%s] with length %i", lex, key, len); */

    int char_counter = 0;

    int pointer = 0;

    while (char_counter < len)

    {

        /* if the first bit of the current char is 1 */

        if (key[pointer] & ESCAPE_MASK)

        {

            /* 

             * then key[pointer] is an escape character and we use it to count

             * (only the weightest part)

             */

            unsigned char escape_char = ((key[pointer] & WEIGHT_MASK) << 1);

            while (escape_char & ESCAPE_MASK && key[pointer] == lex[pointer])

            {

                escape_char = escape_char << 1;

                ++pointer;

            }

        }

        ++char_counter;         /* and we are on a new utf8 character */

        if (key[pointer] != lex[pointer])

        {

            return 0;

            /* printf(" NO\n", lex, key, len); */

        }

        ++pointer;

    }

    if (lex[pointer] != '\0')

    {

        return 0;

        /* printf(" NO\n"); */

    }

    /* printf(" YES\n"); */

    return 1;

}

extern int utf8_strlen(const char *str)

{

    int char_counter = 0;

    while (*str)

    {

        str = utf8_next_char(str);

        ++char_counter;         /* and we are on a new utf8 character */

    }

    return char_counter;

}

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