ff_string.c

/*
 * FreeRTOS+FAT V2.3.3
 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

/**
 *	@file		ff_string.c
 *	@ingroup	STRING
 *
 *	@defgroup	STRING	FreeRTOS+FAT String Library
 *	@brief		Portable String Library for FreeRTOS+FAT
 *
 *
 **/

#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "ff_headers.h"

#if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
    #include <wchar.h>
    #include <wctype.h>
#endif

/*
 *	These will eventually be moved into a platform independent string
 *	library. Which will be optional. (To allow the use of system specific versions).
 */

#if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
    void FF_cstrntowcs( FF_T_WCHAR * wcsDest,
                        const char * szpSource,
                        uint32_t ulLength )
    {
        while( ( *szpSource != '\0' ) && ( ulLength-- != 0 ) )
        {
            *( wcsDest++ ) = *( szpSource++ );
        }

        *wcsDest = '\0';
    }
#endif /* ffconfigUNICODE_UTF16_SUPPORT */
/*-----------------------------------------------------------*/

#if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
    void FF_cstrtowcs( FF_T_WCHAR * wcsDest,
                       const char * szpSource )
    {
        while( *szpSource != '\0' )
        {
            *wcsDest++ = ( FF_T_WCHAR ) *( szpSource++ );
        }

        *wcsDest = '\0';
    }
#endif /* ffconfigUNICODE_UTF16_SUPPORT */
/*-----------------------------------------------------------*/

#if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
    void FF_wcstocstr( char * szpDest,
                       const FF_T_WCHAR * wcsSource )
    {
        while( *wcsSource != '\0' )
        {
            *szpDest++ = ( int8_t ) *( wcsSource++ );
        }

        *szpDest = '\0';
    }
#endif /* ffconfigUNICODE_UTF16_SUPPORT */
/*-----------------------------------------------------------*/

#if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
    void FF_wcsntocstr( char * szpDest,
                        const FF_T_WCHAR * wcsSource,
                        uint32_t ulLength )
    {
        while( ( *wcsSource != '\0' ) && ( ulLength-- != 0 ) )
        {
            *( szpDest++ ) = ( int8_t ) *( wcsSource++ );
        }

        *szpDest = '\0';
    }
#endif /* ffconfigUNICODE_UTF16_SUPPORT */
/*-----------------------------------------------------------*/

/*-----------------------------------------------------------*/

#if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
    void FF_toupper( FF_T_WCHAR * string,
                     uint32_t ulLength )
    {
        uint32_t i;

        for( i = 0; i < ulLength; i++ )
        {
            string[ i ] = towupper( string[ i ] );
        }
    }
    /*-----------------------------------------------------------*/

    void FF_tolower( FF_T_WCHAR * string,
                     uint32_t ulLength )
    {
        uint32_t i;

        for( i = 0; i < ulLength; i++ )
        {
            string[ i ] = towlower( string[ i ] );
        }
    }
    /*-----------------------------------------------------------*/

#else /* ffconfigUNICODE_UTF16_SUPPORT */
    void FF_toupper( char * string,
                     uint32_t ulLength )
    {
        uint32_t i;

        for( i = 0; i < ulLength; i++ )
        {
            if( ( string[ i ] >= 'a' ) && ( string[ i ] <= 'z' ) )
            {
                string[ i ] -= 32;
            }

            if( string[ i ] == '\0' )
            {
                break;
            }
        }
    }
    /*-----------------------------------------------------------*/

    void FF_tolower( char * string,
                     uint32_t ulLength )
    {
        uint32_t i;

        for( i = 0; i < ulLength; i++ )
        {
            if( ( string[ i ] >= 'A' ) && ( string[ i ] <= 'Z' ) )
            {
                string[ i ] += 32;
            }

            if( string[ i ] == '\0' )
            {
                break;
            }
        }
    }
    /*-----------------------------------------------------------*/

#endif /* ffconfigUNICODE_UTF16_SUPPORT */


/**
 *	@private
 *	@brief	Compares 2 strings for the specified length, and returns pdTRUE is they are identical
 *			otherwise pdFALSE is returned.
 *
 **/

#if ( ffconfigUNICODE_UTF16_SUPPORT == 0 )
    BaseType_t FF_strmatch( const char * str1,
                            const char * str2,
                            BaseType_t xLength )
    {
        register BaseType_t i;
        register char char1, char2;

        if( xLength == 0 )
        {
            xLength = strlen( str1 );

            if( xLength != ( BaseType_t ) strlen( str2 ) )
            {
                return pdFALSE;
            }
        }

        for( i = 0; i < xLength; i++ )
        {
            char1 = str1[ i ];
            char2 = str2[ i ];

            if( ( char1 >= 'A' ) && ( char1 <= 'Z' ) )
            {
                char1 += 32;
            }

            if( ( char2 >= 'A' ) && ( char2 <= 'Z' ) )
            {
                char2 += 32;
            }

            if( char1 != char2 )
            {
                return pdFALSE;
            }
        }

        return pdTRUE;
    }
#else /* ffconfigUNICODE_UTF16_SUPPORT */
    BaseType_t FF_strmatch( const FF_T_WCHAR * str1,
                            const FF_T_WCHAR * str2,
                            BaseType_t xLength )
    {
        register BaseType_t i;
        register FF_T_WCHAR char1, char2;

        if( xLength == 0 )
        {
            xLength = wcslen( str1 );

            if( xLength != wcslen( str2 ) )
            {
                return pdFALSE;
            }
        }

        for( i = 0; i < xLength; i++ )
        {
            char1 = towlower( str1[ i ] );
            char2 = towlower( str2[ i ] );

            if( char1 != char2 )
            {
                return pdFALSE;
            }
        }

        return pdTRUE;
    }
#endif /* ffconfigUNICODE_UTF16_SUPPORT */

/**
 *	@private
 *	@brief	A re-entrant Strtok function. No documentation is provided :P
 *			Use at your own risk. (This is for FreeRTOS+FAT's use only).
 **/

#if ( ffconfigUNICODE_UTF16_SUPPORT == 0 )
    char * FF_strtok( const char * string,
                      char * token,
                      uint16_t * tokenNumber,
                      BaseType_t * last,
                      BaseType_t xLength )
    {
        uint16_t i, y, tokenStart, tokenEnd = 0;

        i = 0;
        y = 0;

        if( ( string[ i ] == '\\' ) || ( string[ i ] == '/' ) )
        {
            i++;
        }

        tokenStart = i;

        while( i < xLength )
        {
            if( ( string[ i ] == '\\' ) || ( string[ i ] == '/' ) )
            {
                y++;

                if( y == *tokenNumber )
                {
                    tokenStart = ( uint16_t ) ( i + 1 );
                }

                if( y == ( *tokenNumber + 1 ) )
                {
                    tokenEnd = i;
                    break;
                }
            }

            i++;
        }

        if( tokenEnd == 0 )
        {
            if( *last == pdTRUE )
            {
                return NULL;
            }
            else
            {
                *last = pdTRUE;
            }

            tokenEnd = i;
        }

        if( ( tokenEnd - tokenStart ) < ffconfigMAX_FILENAME )
        {
            memcpy( token, ( string + tokenStart ), ( uint32_t ) ( tokenEnd - tokenStart ) );
            token[ tokenEnd - tokenStart ] = '\0';
        }
        else
        {
            memcpy( token, ( string + tokenStart ), ( uint32_t ) ( ffconfigMAX_FILENAME ) );
            token[ ffconfigMAX_FILENAME - 1 ] = '\0';
        }

        /*token[tokenEnd - tokenStart] = '\0'; */
        *tokenNumber += 1;

        return token;
    }
#else /* ffconfigUNICODE_UTF16_SUPPORT */
    FF_T_WCHAR * FF_strtok( const FF_T_WCHAR * string,
                            FF_T_WCHAR * token,
                            uint16_t * tokenNumber,
                            BaseType_t * last,
                            BaseType_t xLength )
    {
        uint16_t i, y, tokenStart, tokenEnd = 0;

        i = 0;
        y = 0;

        if( ( string[ i ] == '\\' ) || ( string[ i ] == '/' ) )
        {
            i++;
        }

        tokenStart = i;

        while( i < xLength )
        {
            if( ( string[ i ] == '\\' ) || ( string[ i ] == '/' ) )
            {
                y++;

                if( y == *tokenNumber )
                {
                    tokenStart = ( uint16_t ) ( i + 1 );
                }

                if( y == ( *tokenNumber + 1 ) )
                {
                    tokenEnd = i;
                    break;
                }
            }

            i++;
        }

        if( tokenEnd == 0 )
        {
            if( *last == pdTRUE )
            {
                return NULL;
            }
            else
            {
                *last = pdTRUE;
            }

            tokenEnd = i;
        }

        if( ( tokenEnd - tokenStart ) < ffconfigMAX_FILENAME )
        {
            memcpy( token, ( string + tokenStart ), ( uint32_t ) ( tokenEnd - tokenStart ) * sizeof( FF_T_WCHAR ) );
            token[ tokenEnd - tokenStart ] = '\0';
        }
        else
        {
            memcpy( token, ( string + tokenStart ), ( uint32_t ) ( ffconfigMAX_FILENAME ) * sizeof( FF_T_WCHAR ) );
            token[ ffconfigMAX_FILENAME - 1 ] = '\0';
        }

        /*token[tokenEnd - tokenStart] = '\0'; */
        *tokenNumber += 1;

        return token;
    }
#endif /* ffconfigUNICODE_UTF16_SUPPORT */

/* UTF-8 Routines */

/*
 * UCS-4 range (hex.)           UTF-8 octet sequence (binary)
 * 0000 0000-0000 007F   0xxxxxxx
 * 0000 0080-0000 07FF   110xxxxx 10xxxxxx
 * 0000 0800-0000 FFFF   1110xxxx 10xxxxxx 10xxxxxx
 *
 * 0001 0000-001F FFFF   11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
 * 0020 0000-03FF FFFF   111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx	-- We don't encode these because we won't receive them. (Invalid UNICODE).
 * 0400 0000-7FFF FFFF   1111110x 10xxxxxx ... 10xxxxxx					-- We don't encode these because we won't receive them. (Invalid UNICODE).
 */

#if ( ( ffconfigUNICODE_UTF16_SUPPORT != 0 ) && ( WCHAR_MAX > 0xFFFF ) ) || ( ffconfigUNICODE_UTF8_SUPPORT != 0 )
    UBaseType_t FF_GetUtf16SequenceLen( uint16_t usLeadChar )
    {
        UBaseType_t uxReturn;

        if( ( usLeadChar & 0xFC00 ) == 0xD800 )
        {
            uxReturn = 2;
        }
        else
        {
            uxReturn = 1;
        }

        return uxReturn;
    } /* FF_GetUtf16SequenceLen() */
#endif /* if ( ( ffconfigUNICODE_UTF16_SUPPORT != 0 ) && ( WCHAR_MAX > 0xFFFF ) ) || ( ffconfigUNICODE_UTF8_SUPPORT != 0 ) */
/*-----------------------------------------------------------*/

/*
 *  Returns the number of UTF-8 units read.
 *  Will not exceed ulSize UTF-16 units. (ulSize * 2 bytes).
 */

/*
 * UCS-4 range (hex.)           UTF-8 octet sequence (binary)
 * 0000 0000-0000 007F   0xxxxxxx
 * 0000 0080-0000 07FF   110xxxxx 10xxxxxx
 * 0000 0800-0000 FFFF   1110xxxx 10xxxxxx 10xxxxxx
 *
 * 0001 0000-001F FFFF   11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
 * 0020 0000-03FF FFFF   111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx	-- We don't encode these because we won't receive them. (Invalid UNICODE).
 * 0400 0000-7FFF FFFF   1111110x 10xxxxxx ... 10xxxxxx					-- We don't encode these because we won't receive them. (Invalid UNICODE).
 */
#if ( ffconfigUNICODE_UTF8_SUPPORT != 0 )
    int32_t FF_Utf8ctoUtf16c( uint16_t * utf16Dest,
                              const uint8_t * utf8Source,
                              uint32_t ulSize )
    {
        uint32_t ulUtf32char;
        uint16_t utf16Source = 0;
        register int32_t lSequenceNumber = 0;

        /* Count number of set bits before a zero. */
        while( ( ( *utf8Source != '\0' ) & ( 0x80 >> ( lSequenceNumber ) ) ) )
        {
            lSequenceNumber++;
        }

        if( lSequenceNumber == 0UL )
        {
            lSequenceNumber++;
        }

        if( ulSize == 0UL )
        {
            /* Returned value becomes an error, with the highest bit set. */
            lSequenceNumber = FF_ERR_UNICODE_DEST_TOO_SMALL | FF_UTF8CTOUTF16C;
        }
        else
        {
            switch( lSequenceNumber )
            {
                case 1:
                    utf16Source = ( uint16_t ) *utf8Source;
                    memcpy( utf16Dest, &utf16Source, sizeof( uint16_t ) );
                    break;

                case 2:
                    utf16Source = ( uint16_t ) ( ( *utf8Source & 0x1F ) << 6 ) | ( ( *( utf8Source + 1 ) & 0x3F ) );
                    memcpy( utf16Dest, &utf16Source, sizeof( uint16_t ) );
                    break;

                case 3:
                    utf16Source = ( uint16_t ) ( ( *utf8Source & 0x0F ) << 12 ) | ( ( *( utf8Source + 1 ) & 0x3F ) << 6 ) | ( ( *( utf8Source + 2 ) & 0x3F ) );
                    memcpy( utf16Dest, &utf16Source, sizeof( uint16_t ) );
                    break;

                case 4:

                    if( ulSize < 2 )
                    {
                        /* Returned value becomes an error. */
                        lSequenceNumber = FF_ERR_UNICODE_DEST_TOO_SMALL | FF_UTF8CTOUTF16C;
                    }
                    else
                    {
                        /* Convert to UTF-32 and then into UTF-16 */
                        ulUtf32char = ( uint16_t )
                                      ( ( *utf8Source & 0x0F ) << 18 ) |
                                      ( ( *( utf8Source + 1 ) & 0x3F ) << 12 ) |
                                      ( ( *( utf8Source + 2 ) & 0x3F ) << 6 ) |
                                      ( ( *( utf8Source + 3 ) & 0x3F ) );

                        utf16Source = ( uint16_t ) ( ( ( ulUtf32char - 0x10000 ) & 0xFFC00 ) >> 10 ) | 0xD800;
                        memcpy( utf16Dest, &utf16Source, sizeof( uint16_t ) );
                        utf16Source = ( uint16_t ) ( ( ( ulUtf32char - 0x10000 ) & 0x003FF ) >> 00 ) | 0xDC00;
                        memcpy( utf16Dest + 1, &utf16Source, sizeof( uint16_t ) );
                    }

                    break;

                default:
                    break;
            }
        }

        return lSequenceNumber;
    } /* FF_Utf8ctoUtf16c() */
#endif /* ffconfigUNICODE_UTF8_SUPPORT */

/*-----------------------------------------------------------*/

/*
 *  Returns the number of UTF-8 units required to encode the UTF-16 sequence.
 *  Will not exceed ulSize UTF-8 units. (ulSize  * 1 bytes).
 */
#if ( ffconfigUNICODE_UTF8_SUPPORT != 0 )
    int32_t FF_Utf16ctoUtf8c( uint8_t * utf8Dest,
                              const uint16_t * utf16Source,
                              uint32_t ulSize )
    {
        uint32_t ulUtf32char;
        uint16_t ulUtf16char;
        int32_t lReturn = 0L;

        do
        {
            if( ulSize == 0UL )
            {
                lReturn = FF_ERR_UNICODE_DEST_TOO_SMALL | FF_UTF16CTOUTF8C;
                break;
            }

            memcpy( &ulUtf16char, utf16Source, sizeof( uint16_t ) );

            /* A surrogate sequence was encountered. Must transform to UTF32 first. */
            if( ( ulUtf16char & 0xF800 ) == 0xD800 )
            {
                ulUtf32char = ( ( uint32_t ) ( ulUtf16char & 0x003FF ) << 10 ) + 0x10000;

                memcpy( &ulUtf16char, utf16Source + 1, sizeof( uint16_t ) );

                if( ( ulUtf16char & 0xFC00 ) != 0xDC00 )
                {
                    /* Invalid UTF-16 sequence. */
                    lReturn = FF_ERR_UNICODE_INVALID_SEQUENCE | FF_UTF16CTOUTF8C;
                    break;
                }

                ulUtf32char |= ( ( uint32_t ) ( ulUtf16char & 0x003FF ) );
            }
            else
            {
                ulUtf32char = ( uint32_t ) ulUtf16char;
            }

            /* Now convert to the UTF-8 sequence. */
            /* Single byte UTF-8 sequence. */
            if( ulUtf32char < 0x00000080 )
            {
                *( utf8Dest + 0 ) = ( uint8_t ) ulUtf32char;
                lReturn = 1;
                break;
            }

            /* Double byte UTF-8 sequence. */
            if( ulUtf32char < 0x00000800 )
            {
                if( ulSize < 2 )
                {
                    lReturn = FF_ERR_UNICODE_DEST_TOO_SMALL | FF_UTF16CTOUTF8C;
                }
                else
                {
                    *( utf8Dest + 0 ) = ( uint8_t ) ( 0xC0 | ( ( ulUtf32char >> 6 ) & 0x1F ) );
                    *( utf8Dest + 1 ) = ( uint8_t ) ( 0x80 | ( ( ulUtf32char >> 0 ) & 0x3F ) );
                    lReturn = 2;
                }

                break;
            }

            /* Triple byte UTF-8 sequence. */
            if( ulUtf32char < 0x00010000 )
            {
                if( ulSize < 3 )
                {
                    lReturn = FF_ERR_UNICODE_DEST_TOO_SMALL | FF_UTF16CTOUTF8C;
                }
                else
                {
                    *( utf8Dest + 0 ) = ( uint8_t ) ( 0xE0 | ( ( ulUtf32char >> 12 ) & 0x0F ) );
                    *( utf8Dest + 1 ) = ( uint8_t ) ( 0x80 | ( ( ulUtf32char >> 6 ) & 0x3F ) );
                    *( utf8Dest + 2 ) = ( uint8_t ) ( 0x80 | ( ( ulUtf32char >> 0 ) & 0x3F ) );
                    lReturn = 3;
                }

                break;
            }

            /* Quadruple byte UTF-8 sequence. */
            if( ulUtf32char < 0x00200000 )
            {
                if( ulSize < 4 )
                {
                    lReturn = FF_ERR_UNICODE_DEST_TOO_SMALL | FF_UTF16CTOUTF8C;
                }
                else
                {
                    *( utf8Dest + 0 ) = ( uint8_t ) ( 0xF0 | ( ( ulUtf32char >> 18 ) & 0x07 ) );
                    *( utf8Dest + 1 ) = ( uint8_t ) ( 0x80 | ( ( ulUtf32char >> 12 ) & 0x3F ) );
                    *( utf8Dest + 2 ) = ( uint8_t ) ( 0x80 | ( ( ulUtf32char >> 6 ) & 0x3F ) );
                    *( utf8Dest + 3 ) = ( uint8_t ) ( 0x80 | ( ( ulUtf32char >> 0 ) & 0x3F ) );
                    lReturn = 4;
                }

                break;
            }

            lReturn = FF_ERR_UNICODE_INVALID_CODE | FF_UTF16CTOUTF8C; /* Invalid Character */
        }
        while( pdFALSE );

        return lReturn;
    } /* FF_Utf16ctoUtf8c() */
#endif /* ffconfigUNICODE_UTF8_SUPPORT */
/*-----------------------------------------------------------*/

/* UTF-16 Support Functions */

/* Converts a UTF-32 Character into its equivalent UTF-16 sequence. */
#if ( ffconfigUNICODE_UTF16_SUPPORT != 0 ) && ( WCHAR_MAX > 0xFFFF )
    int32_t FF_Utf32ctoUtf16c( uint16_t * utf16Dest,
                               uint32_t utf32char,
                               uint32_t ulSize )
    {
        int32_t lReturn;

        /* Check that its a valid UTF-32 wide-char!	*/

        /* This range is not a valid Unicode code point. */
        if( ( utf32char >= 0xD800 ) && ( utf32char <= 0xDFFF ) )
        {
            lReturn = FF_ERR_UNICODE_INVALID_CODE | FF_UTF32CTOUTF16C; /* Invalid character. */
        }
        else if( utf32char < 0x10000 )
        {
            *utf16Dest = ( uint16_t ) utf32char; /* Simple conversion! Char comes within UTF-16 space (without surrogates). */
            lReturn = 1;
        }
        else if( ulSize < 2 )
        {
            lReturn = FF_ERR_UNICODE_DEST_TOO_SMALL | FF_UTF32CTOUTF16C; /* Not enough UTF-16 units to record this character. */
        }
        else if( utf32char < 0x00200000 )
        {
            /* Conversion to a UTF-16 Surrogate pair! */
            /*valueImage = utf32char - 0x10000; */
            *( utf16Dest + 0 ) = ( uint16_t ) ( ( ( utf32char - 0x10000 ) & 0xFFC00 ) >> 10 ) | 0xD800;
            *( utf16Dest + 1 ) = ( uint16_t ) ( ( ( utf32char - 0x10000 ) & 0x003FF ) >> 00 ) | 0xDC00;

            lReturn = 2; /* Surrogate pair encoded value. */
        }
        else
        {
            /* Invalid Character */
            lReturn = FF_ERR_UNICODE_INVALID_CODE | FF_UTF32CTOUTF16C;
        }

        return lReturn;
    } /* FF_Utf32ctoUtf16c() */
#endif /* #if( ffconfigUNICODE_UTF16_SUPPORT != 0 ) && ( WCHAR_MAX > 0xFFFF ) */
/*-----------------------------------------------------------*/

/* Converts a UTF-16 sequence into its equivalent UTF-32 code point. */
#if ( ffconfigNOT_USED_FOR_NOW != 0 )
    int32_t FF_Utf16ctoUtf32c( uint32_t * utf32Dest,
                               const uint16_t * utf16Source )
    {
        int32_t lReturn;

        /*Not a surrogate sequence. */
        if( ( *utf16Source & 0xFC00 ) != 0xD800 )
        {
            *utf32Dest = ( uint32_t ) *utf16Source;
            lReturn = 1; /* A single UTF-16 item was used to represent the character. */
        }
        else
        {
            *utf32Dest = ( ( uint32_t ) ( *( utf16Source + 0 ) & 0x003FF ) << 10 ) + 0x10000;

            if( ( *( utf16Source + 1 ) & 0xFC00 ) != 0xDC00 )
            {
                lReturn = FF_ERR_UNICODE_INVALID_SEQUENCE | FF_UTF16CTOUTF32C; /* Invalid UTF-16 sequence. */
            }
            else
            {
                *utf32Dest |= ( ( uint32_t ) ( *( utf16Source + 1 ) & 0x003FF ) );
                lReturn = 2; /* 2 utf-16 units make up the Unicode code-point. */
            }
        }

        return lReturn;
    } /* FF_Utf16ctoUtf32c() */
#endif /* ffconfigNOT_USED_FOR_NOW */
/*-----------------------------------------------------------*/

/*
 *  Returns the total number of UTF-16 items required to represent
 *  the provided UTF-32 string in UTF-16 form.
 */

/*
 * UBaseType_t FF_Utf32GetUtf16Len( const uint32_t *utf32String )
 * {
 *  UBaseType_t utf16len = 0;
 *
 *  while( *utf32String )
 *  {
 *      if( *utf32String++ <= 0xFFFF )
 *      {
 *          utf16len++;
 *      }
 *      else
 *      {
 *          utf16len += 2;
 *      }
 *  }
 *
 *  return utf16len;
 * }
 */
/*-----------------------------------------------------------*/


/* String conversions */

#if ( ffconfigNOT_USED_FOR_NOW != 0 )
    int32_t FF_Utf32stoUtf8s( uint8_t * Utf8String,
                              uint32_t * Utf32String )
    {
        int i = 0, y = 0;

        uint16_t utf16buffer[ 2 ];

        while( Utf32String[ i ] != '\0' )
        {
            /* Convert to a UTF16 char. */
            FF_Utf32ctoUtf16c( utf16buffer, Utf32String[ i ], 2 );
            /* Now convert the UTF16 to UTF8 sequence. */
            y += FF_Utf16ctoUtf8c( &Utf8String[ y ], utf16buffer, 4 );
            i++;
        }

        Utf8String[ y ] = '\0';

        return 0;
    } /* FF_Utf32stoUtf8s() */
#endif /* ffconfigNOT_USED_FOR_NOW */
/*-----------------------------------------------------------*/