charset_convert.hh

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/*
 * Copyright (c) 2016 Zhao DAI <daidodo@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or any
 * later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see accompanying file LICENSE.txt
 * or <http://www.gnu.org/licenses/>.
 */

#ifndef DOZERG_CHARSET_CONVERT_H_20130513
#define DOZERG_CHARSET_CONVERT_H_20130513

#include <iconv.h>
#include <cassert>
#include "to_string.hh"

NS_SERVER_BEGIN

class CCharsetConvert
{
public:
    enum EMode{
        kNormal = 0,
        kTranslit,
        kIgnore
    };
    CCharsetConvert()
        : cv_(iconv_t(-1))
        , mode_(kNormal)
    {}
    ~CCharsetConvert(){
        if(valid())
            ::iconv_close(cv_);
    }
    CCharsetConvert(const std::string & fromCode, const std::string & toCode, EMode mode = kNormal)
        : cv_(iconv_t(-1))
        , mode_(kNormal)
    {
        init(fromCode, toCode, mode);
    }
    bool init(const std::string & fromCode, const std::string & toCode, EMode mode = kNormal){
        if(valid())
            return false;
        if(fromCode.empty() || toCode.empty())
            return false;
        std::string t = toCode;
        switch(mode){
            case kTranslit:t += "//TRANSLIT";break;
            case kIgnore:t += "//IGNORE";break;
            default:;
        }
        from_ = fromCode;
        to_ = toCode;
        mode_ = mode;
        cv_ = ::iconv_open(t.c_str(), fromCode.c_str());
        return valid();
    }
    bool valid() const{return (iconv_t(-1) != cv_);}
    const std::string fromCode() const{return from_;}
    const std::string toCode() const{return to_;}
    EMode mode() const{return mode_;}
    bool convert(const std::string & source, std::string & dest){
        if(!valid())
            return false;
        if(source.empty())
            return true;
        ::iconv(cv_, NULL, NULL, NULL, NULL);    //reset init state;
        char * inbuf = const_cast<char *>(&source[0]);  //iconv()'s bug
        size_t inLen = source.size();
        for(char buf[64];inLen > 0;){
            const size_t inOld = inLen;
            char * outbuf = buf;
            size_t outLen = sizeof buf;
            ::iconv(cv_, &inbuf, &inLen, &outbuf, &outLen);
            if(inOld <= inLen)   //cannot proceed
                return false;
            if(buf != outbuf){
                assert(buf < outbuf);
                dest.append(buf, outbuf - buf);
            }
        }
        return true;
    }
    std::string toString() const{
        CToString oss;
        oss<<"{cv_="<<cv_
            <<", from_="<<from_
            <<", to_="<<to_
            <<", mode_="<<mode_
            <<'}';
        return oss.str();
    }
private:
    CCharsetConvert(const CCharsetConvert &);   //disable copy and assignment
    CCharsetConvert & operator =(const CCharsetConvert &);
    //members
    std::string from_, to_;
    iconv_t cv_;
    EMode mode_;
};

NS_SERVER_END

#endif