utf8.hpp

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/*
 * Copyright (c) 2014 Patrick P. Frey
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
#ifndef _STRUS_BASE_UTF8_ENCODING_DECODING_HPP_INCLUDED
#define _STRUS_BASE_UTF8_ENCODING_DECODING_HPP_INCLUDED
#include "strus/base/bitOperations.hpp"
#include "strus/base/stdint.h"

namespace strus
{
enum {
        B11111111=0xFF,
        B01111111=0x7F,
        B00111111=0x3F,
        B00011111=0x1F,
        B00001111=0x0F,
        B00000111=0x07,
        B00000011=0x03,
        B00000001=0x01,
        B00000000=0x00,
        B10000000=0x80,
        B11000000=0xC0,
        B11100000=0xE0,
        B11110000=0xF0,
        B11111000=0xF8,
        B11111100=0xFC,
        B11111110=0xFE,

        B11011111=B11000000|B00011111,
        B11101111=B11100000|B00001111,
        B11110111=B11110000|B00000111,
        B11111011=B11111000|B00000011,
        B11111101=B11111100|B00000001
};

static inline bool utf8midchr( unsigned char ch)
{
        return (ch & B11000000) == B10000000;
}

static inline const char* utf8prev( char const* end)
{
        for (--end; ((unsigned char)*end & B11000000) == B10000000; --end){}
        return end;
}

static inline unsigned char utf8charlen( unsigned char ch)
{
        unsigned char cl = 9-BitOperations::bitScanReverse( (uint8_t)(ch^0xFF));
        return cl>2?(cl-1):1;
}

int32_t utf8decode( const char* itr, unsigned int charsize);

std::size_t utf8encode( char* buf, int32_t chr);

} //namespace
#endif