boost/libs/locale/src/icu/codecvt.cpp

//
//  Copyright (c) 2009-2011 Artyom Beilis (Tonkikh)
//
//  Distributed under the Boost Software License, Version 1.0. (See
//  accompanying file LICENSE_1_0.txt or copy at
//  http://www.boost.org/LICENSE_1_0.txt)
//
#define BOOST_LOCALE_SOURCE
#include <boost/locale/encoding.hpp>
#include "../encoding/conv.hpp"
#include "all_generator.hpp"
#include "uconv.hpp"
#include <unicode/ucnv.h>
#include <unicode/ucnv_err.h>
#include <boost/locale/util.hpp>
#include "codecvt.hpp"

#ifdef BOOST_MSVC
#  pragma warning(disable : 4244) // loose data 
#endif

#include "icu_util.hpp"
#include <vector>
namespace boost {
namespace locale {
namespace impl_icu {
    class uconv_converter : public util::base_converter {
    public:
       
        uconv_converter(std::string const &encoding) :
            encoding_(encoding)
        {
            UErrorCode err=U_ZERO_ERROR;
            
            // No need to check err each time, this
            // is how ICU works.
            cvt_ = ucnv_open(encoding.c_str(),&err);
            ucnv_setFromUCallBack(cvt_,UCNV_FROM_U_CALLBACK_STOP,0,0,0,&err);
            ucnv_setToUCallBack(cvt_,UCNV_TO_U_CALLBACK_STOP,0,0,0,&err);

            if(!cvt_ || U_FAILURE(err)) {
                if(cvt_)
                    ucnv_close(cvt_);
                throw conv::invalid_charset_error(encoding);
            }
            
            max_len_ = ucnv_getMaxCharSize(cvt_);
        }
        
        virtual ~uconv_converter()
        {
            ucnv_close(cvt_);
        }

        virtual bool is_thread_safe() const
        {
            return false;
        }

        virtual uconv_converter *clone() const
        {
            return new uconv_converter(encoding_);
        }

        uint32_t to_unicode(char const *&begin,char const *end)
        {
            UErrorCode err=U_ZERO_ERROR;
            char const *tmp = begin;
            UChar32 c=ucnv_getNextUChar(cvt_,&tmp,end,&err);
            ucnv_reset(cvt_);
            if(err == U_TRUNCATED_CHAR_FOUND) {
                return incomplete;
            }
            if(U_FAILURE(err)) {
                return illegal;
            }

            begin = tmp;
            return c;
        }

        uint32_t from_unicode(uint32_t u,char *begin,char const *end)
        {
            UChar code_point[2]={0};
            int len;
            if(u<=0xFFFF) {
                if(0xD800 <=u && u<= 0xDFFF) // No surragates
                    return illegal;
                code_point[0]=u;
                len=1;
            }
            else {
                u-=0x10000;
                code_point[0]=0xD800 | (u>>10);
                code_point[1]=0xDC00 | (u & 0x3FF);
                len=2;
            }
            UErrorCode err=U_ZERO_ERROR;
            int olen = ucnv_fromUChars(cvt_,begin,end-begin,code_point,len,&err);
            ucnv_reset(cvt_);
            if(err == U_BUFFER_OVERFLOW_ERROR)
                return incomplete;
            if(U_FAILURE(err))
                return illegal;
            return olen;
        }

        virtual int max_len() const
        {
            return max_len_;
        }

    private:
        std::string encoding_;
        UConverter *cvt_;
        int max_len_;
    };
    
    std::auto_ptr<util::base_converter> create_uconv_converter(std::string const &encoding)
    {
        std::auto_ptr<util::base_converter> cvt;
        try {
            cvt.reset(new uconv_converter(encoding));
        }
        catch(std::exception const &/*e*/)
        {
            // no encoding so we return empty pointer
        }
        return cvt;
    }

    std::locale create_codecvt(std::locale const &in,std::string const &encoding,character_facet_type type)
    {
        std::auto_ptr<util::base_converter> cvt;
        if(conv::impl::normalize_encoding(encoding.c_str())=="utf8")
            cvt = util::create_utf8_converter(); 
        else {
            cvt = util::create_simple_converter(encoding);
            if(!cvt.get()) {
                try {
                    cvt = create_uconv_converter(encoding);
                }
                catch(std::exception const &/*e*/)
                {
                    // not too much we can do
                }
            }
        }
        return util::create_codecvt(in,cvt,type);
    }

} // impl_icu
} // locale 
} // boost

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