encodings.h Source File

encodings.h Source File#

Composable Kernel: encodings.h Source File
// Tencent is pleased to support the open source community by making RapidJSON available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
 
#ifndef RAPIDJSON_ENCODINGS_H_
#define RAPIDJSON_ENCODINGS_H_
 
#include "rapidjson.h"
 
#if defined(_MSC_VER) && !defined(__clang__)
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(4244) // conversion from 'type1' to 'type2', possible loss of data
RAPIDJSON_DIAG_OFF(4702) // unreachable code
#elif defined(__GNUC__)
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(effc++)
RAPIDJSON_DIAG_OFF(overflow)
#endif
 
RAPIDJSON_NAMESPACE_BEGIN
// Encoding
    template<typename OutputStream>
    static void Encode(OutputStream& os, unsigned codepoint);
    template <typename InputStream>
    static bool Decode(InputStream& is, unsigned* codepoint);
    template <typename InputStream, typename OutputStream>
    static bool Validate(InputStream& is, OutputStream& os);
 
    // The following functions are deal with byte streams.
    template <typename InputByteStream>
    static CharType TakeBOM(InputByteStream& is);
    template <typename InputByteStream>
    static Ch Take(InputByteStream& is);
    template <typename OutputByteStream>
    static void PutBOM(OutputByteStream& os);
    template <typename OutputByteStream>
    static void Put(OutputByteStream& os, Ch c);
};
\endcode
*/
// UTF8
template <typename CharType = char>
struct UTF8
{
    typedef CharType Ch;
 
    enum
    {
        supportUnicode = 1
    };
 
    template <typename OutputStream>
    static void Encode(OutputStream& os, unsigned codepoint)
    {
        if(codepoint <= 0x7F)
            os.Put(static_cast<Ch>(codepoint & 0xFF));
        else if(codepoint <= 0x7FF)
        {
            os.Put(static_cast<Ch>(0xC0 | ((codepoint >> 6) & 0xFF)));
            os.Put(static_cast<Ch>(0x80 | ((codepoint & 0x3F))));
        }
        else if(codepoint <= 0xFFFF)
        {
            os.Put(static_cast<Ch>(0xE0 | ((codepoint >> 12) & 0xFF)));
            os.Put(static_cast<Ch>(0x80 | ((codepoint >> 6) & 0x3F)));
            os.Put(static_cast<Ch>(0x80 | (codepoint & 0x3F)));
        }
        else
        {
            RAPIDJSON_ASSERT(codepoint <= 0x10FFFF);
            os.Put(static_cast<Ch>(0xF0 | ((codepoint >> 18) & 0xFF)));
            os.Put(static_cast<Ch>(0x80 | ((codepoint >> 12) & 0x3F)));
            os.Put(static_cast<Ch>(0x80 | ((codepoint >> 6) & 0x3F)));
            os.Put(static_cast<Ch>(0x80 | (codepoint & 0x3F)));
        }
    }
 
    template <typename OutputStream>
    static void EncodeUnsafe(OutputStream& os, unsigned codepoint)
    {
        if(codepoint <= 0x7F)
            PutUnsafe(os, static_cast<Ch>(codepoint & 0xFF));
        else if(codepoint <= 0x7FF)
        {
            PutUnsafe(os, static_cast<Ch>(0xC0 | ((codepoint >> 6) & 0xFF)));
            PutUnsafe(os, static_cast<Ch>(0x80 | ((codepoint & 0x3F))));
        }
        else if(codepoint <= 0xFFFF)
        {
            PutUnsafe(os, static_cast<Ch>(0xE0 | ((codepoint >> 12) & 0xFF)));
            PutUnsafe(os, static_cast<Ch>(0x80 | ((codepoint >> 6) & 0x3F)));
            PutUnsafe(os, static_cast<Ch>(0x80 | (codepoint & 0x3F)));
        }
        else
        {
            RAPIDJSON_ASSERT(codepoint <= 0x10FFFF);
            PutUnsafe(os, static_cast<Ch>(0xF0 | ((codepoint >> 18) & 0xFF)));
            PutUnsafe(os, static_cast<Ch>(0x80 | ((codepoint >> 12) & 0x3F)));
            PutUnsafe(os, static_cast<Ch>(0x80 | ((codepoint >> 6) & 0x3F)));
            PutUnsafe(os, static_cast<Ch>(0x80 | (codepoint & 0x3F)));
        }
    }
 
    template <typename InputStream>
    static bool Decode(InputStream& is, unsigned* codepoint)
    {
#define RAPIDJSON_COPY()    \
    c          = is.Take(); \
    *codepoint = (*codepoint << 6) | (static_cast<unsigned char>(c) & 0x3Fu)
#define RAPIDJSON_TRANS(mask) result &= ((GetRange(static_cast<unsigned char>(c)) & mask) != 0)
#define RAPIDJSON_TAIL() \
    RAPIDJSON_COPY();    \
    RAPIDJSON_TRANS(0x70)
        typename InputStream::Ch c = is.Take();
        if(!(c & 0x80))
        {
            *codepoint = static_cast<unsigned char>(c);
            return true;
        }
 
        unsigned char type = GetRange(static_cast<unsigned char>(c));
        if(type >= 32)
        {
            *codepoint = 0;
        }
        else
        {
            *codepoint = (0xFFu >> type) & static_cast<unsigned char>(c);
        }
        bool result = true;
        switch(type)
        {
        case 2: RAPIDJSON_TAIL(); return result;
        case 3:
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            return result;
        case 4:
            RAPIDJSON_COPY();
            RAPIDJSON_TRANS(0x50);
            RAPIDJSON_TAIL();
            return result;
        case 5:
            RAPIDJSON_COPY();
            RAPIDJSON_TRANS(0x10);
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            return result;
        case 6:
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            return result;
        case 10:
            RAPIDJSON_COPY();
            RAPIDJSON_TRANS(0x20);
            RAPIDJSON_TAIL();
            return result;
        case 11:
            RAPIDJSON_COPY();
            RAPIDJSON_TRANS(0x60);
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            return result;
        default: return false;
        }
#undef RAPIDJSON_COPY
#undef RAPIDJSON_TRANS
#undef RAPIDJSON_TAIL
    }
 
    template <typename InputStream, typename OutputStream>
    static bool Validate(InputStream& is, OutputStream& os)
    {
#define RAPIDJSON_COPY() \
    if(c != '\0')        \
    os.Put(c = is.Take())
#define RAPIDJSON_TRANS(mask) result &= ((GetRange(static_cast<unsigned char>(c)) & mask) != 0)
#define RAPIDJSON_TAIL() \
    RAPIDJSON_COPY();    \
    RAPIDJSON_TRANS(0x70)
        Ch c = static_cast<Ch>(-1);
        RAPIDJSON_COPY();
        if(!(c & 0x80))
            return true;
 
        bool result = true;
        switch(GetRange(static_cast<unsigned char>(c)))
        {
        case 2: RAPIDJSON_TAIL(); return result;
        case 3:
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            return result;
        case 4:
            RAPIDJSON_COPY();
            RAPIDJSON_TRANS(0x50);
            RAPIDJSON_TAIL();
            return result;
        case 5:
            RAPIDJSON_COPY();
            RAPIDJSON_TRANS(0x10);
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            return result;
        case 6:
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            return result;
        case 10:
            RAPIDJSON_COPY();
            RAPIDJSON_TRANS(0x20);
            RAPIDJSON_TAIL();
            return result;
        case 11:
            RAPIDJSON_COPY();
            RAPIDJSON_TRANS(0x60);
            RAPIDJSON_TAIL();
            RAPIDJSON_TAIL();
            return result;
        default: return false;
        }
#undef RAPIDJSON_COPY
#undef RAPIDJSON_TRANS
#undef RAPIDJSON_TAIL
    }
 
    static unsigned char GetRange(unsigned char c)
    {
        // Referring to DFA of http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
        // With new mapping 1 -> 0x10, 7 -> 0x20, 9 -> 0x40, such that AND operation can test
        // multiple types.
        static const unsigned char type[] = {
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
            0,    0,    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
            0x10, 0x10, 0x10, 0x10, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,
            0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
            0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
            0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 8,    8,    2,    2,
            2,    2,    2,    2,    2,    2,    2,    2,    2,    2,    2,    2,    2,    2,
            2,    2,    2,    2,    2,    2,    2,    2,    2,    2,    2,    2,    2,    2,
            10,   3,    3,    3,    3,    3,    3,    3,    3,    3,    3,    3,    3,    4,
            3,    3,    11,   6,    6,    6,    5,    8,    8,    8,    8,    8,    8,    8,
            8,    8,    8,    8,
        };
        return type[c];
    }
 
    template <typename InputByteStream>
    static CharType TakeBOM(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        typename InputByteStream::Ch c = Take(is);
        if(static_cast<unsigned char>(c) != 0xEFu)
            return c;
        c = is.Take();
        if(static_cast<unsigned char>(c) != 0xBBu)
            return c;
        c = is.Take();
        if(static_cast<unsigned char>(c) != 0xBFu)
            return c;
        c = is.Take();
        return c;
    }
 
    template <typename InputByteStream>
    static Ch Take(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        return static_cast<Ch>(is.Take());
    }
 
    template <typename OutputByteStream>
    static void PutBOM(OutputByteStream& os)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(0xEFu));
        os.Put(static_cast<typename OutputByteStream::Ch>(0xBBu));
        os.Put(static_cast<typename OutputByteStream::Ch>(0xBFu));
    }
 
    template <typename OutputByteStream>
    static void Put(OutputByteStream& os, Ch c)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(c));
    }
};
// UTF16
template <typename CharType = wchar_t>
struct UTF16
{
    typedef CharType Ch;
    RAPIDJSON_STATIC_ASSERT(sizeof(Ch) >= 2);
 
    enum
    {
        supportUnicode = 1
    };
 
    template <typename OutputStream>
    static void Encode(OutputStream& os, unsigned codepoint)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputStream::Ch) >= 2);
        if(codepoint <= 0xFFFF)
        {
            RAPIDJSON_ASSERT(codepoint < 0xD800 ||
                             codepoint > 0xDFFF); // Code point itself cannot be surrogate pair
            os.Put(static_cast<typename OutputStream::Ch>(codepoint));
        }
        else
        {
            RAPIDJSON_ASSERT(codepoint <= 0x10FFFF);
            unsigned v = codepoint - 0x10000;
            os.Put(static_cast<typename OutputStream::Ch>((v >> 10) | 0xD800));
            os.Put(static_cast<typename OutputStream::Ch>((v & 0x3FF) | 0xDC00));
        }
    }
 
    template <typename OutputStream>
    static void EncodeUnsafe(OutputStream& os, unsigned codepoint)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputStream::Ch) >= 2);
        if(codepoint <= 0xFFFF)
        {
            RAPIDJSON_ASSERT(codepoint < 0xD800 ||
                             codepoint > 0xDFFF); // Code point itself cannot be surrogate pair
            PutUnsafe(os, static_cast<typename OutputStream::Ch>(codepoint));
        }
        else
        {
            RAPIDJSON_ASSERT(codepoint <= 0x10FFFF);
            unsigned v = codepoint - 0x10000;
            PutUnsafe(os, static_cast<typename OutputStream::Ch>((v >> 10) | 0xD800));
            PutUnsafe(os, static_cast<typename OutputStream::Ch>((v & 0x3FF) | 0xDC00));
        }
    }
 
    template <typename InputStream>
    static bool Decode(InputStream& is, unsigned* codepoint)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputStream::Ch) >= 2);
        typename InputStream::Ch c = is.Take();
        if(c < 0xD800 || c > 0xDFFF)
        {
            *codepoint = static_cast<unsigned>(c);
            return true;
        }
        else if(c <= 0xDBFF)
        {
            *codepoint = (static_cast<unsigned>(c) & 0x3FF) << 10;
            c          = is.Take();
            *codepoint |= (static_cast<unsigned>(c) & 0x3FF);
            *codepoint += 0x10000;
            return c >= 0xDC00 && c <= 0xDFFF;
        }
        return false;
    }
 
    template <typename InputStream, typename OutputStream>
    static bool Validate(InputStream& is, OutputStream& os)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputStream::Ch) >= 2);
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputStream::Ch) >= 2);
        typename InputStream::Ch c;
        os.Put(static_cast<typename OutputStream::Ch>(c = is.Take()));
        if(c < 0xD800 || c > 0xDFFF)
            return true;
        else if(c <= 0xDBFF)
        {
            os.Put(c = is.Take());
            return c >= 0xDC00 && c <= 0xDFFF;
        }
        return false;
    }
};
template <typename CharType = wchar_t>
struct UTF16LE : UTF16<CharType>
{
    template <typename InputByteStream>
    static CharType TakeBOM(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        CharType c = Take(is);
        return static_cast<uint16_t>(c) == 0xFEFFu ? Take(is) : c;
    }
 
    template <typename InputByteStream>
    static CharType Take(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        unsigned c = static_cast<uint8_t>(is.Take());
        c |= static_cast<unsigned>(static_cast<uint8_t>(is.Take())) << 8;
        return static_cast<CharType>(c);
    }
 
    template <typename OutputByteStream>
    static void PutBOM(OutputByteStream& os)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>(0xFEu));
    }
 
    template <typename OutputByteStream>
    static void Put(OutputByteStream& os, CharType c)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(static_cast<unsigned>(c) & 0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>((static_cast<unsigned>(c) >> 8) & 0xFFu));
    }
};
template <typename CharType = wchar_t>
struct UTF16BE : UTF16<CharType>
{
    template <typename InputByteStream>
    static CharType TakeBOM(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        CharType c = Take(is);
        return static_cast<uint16_t>(c) == 0xFEFFu ? Take(is) : c;
    }
 
    template <typename InputByteStream>
    static CharType Take(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        unsigned c = static_cast<unsigned>(static_cast<uint8_t>(is.Take())) << 8;
        c |= static_cast<unsigned>(static_cast<uint8_t>(is.Take()));
        return static_cast<CharType>(c);
    }
 
    template <typename OutputByteStream>
    static void PutBOM(OutputByteStream& os)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(0xFEu));
        os.Put(static_cast<typename OutputByteStream::Ch>(0xFFu));
    }
 
    template <typename OutputByteStream>
    static void Put(OutputByteStream& os, CharType c)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>((static_cast<unsigned>(c) >> 8) & 0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>(static_cast<unsigned>(c) & 0xFFu));
    }
};
// UTF32
template <typename CharType = unsigned>
struct UTF32
{
    typedef CharType Ch;
    RAPIDJSON_STATIC_ASSERT(sizeof(Ch) >= 4);
 
    enum
    {
        supportUnicode = 1
    };
 
    template <typename OutputStream>
    static void Encode(OutputStream& os, unsigned codepoint)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputStream::Ch) >= 4);
        RAPIDJSON_ASSERT(codepoint <= 0x10FFFF);
        os.Put(codepoint);
    }
 
    template <typename OutputStream>
    static void EncodeUnsafe(OutputStream& os, unsigned codepoint)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputStream::Ch) >= 4);
        RAPIDJSON_ASSERT(codepoint <= 0x10FFFF);
        PutUnsafe(os, codepoint);
    }
 
    template <typename InputStream>
    static bool Decode(InputStream& is, unsigned* codepoint)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputStream::Ch) >= 4);
        Ch c       = is.Take();
        *codepoint = c;
        return c <= 0x10FFFF;
    }
 
    template <typename InputStream, typename OutputStream>
    static bool Validate(InputStream& is, OutputStream& os)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputStream::Ch) >= 4);
        Ch c;
        os.Put(c = is.Take());
        return c <= 0x10FFFF;
    }
};
template <typename CharType = unsigned>
struct UTF32LE : UTF32<CharType>
{
    template <typename InputByteStream>
    static CharType TakeBOM(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        CharType c = Take(is);
        return static_cast<uint32_t>(c) == 0x0000FEFFu ? Take(is) : c;
    }
 
    template <typename InputByteStream>
    static CharType Take(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        unsigned c = static_cast<uint8_t>(is.Take());
        c |= static_cast<unsigned>(static_cast<uint8_t>(is.Take())) << 8;
        c |= static_cast<unsigned>(static_cast<uint8_t>(is.Take())) << 16;
        c |= static_cast<unsigned>(static_cast<uint8_t>(is.Take())) << 24;
        return static_cast<CharType>(c);
    }
 
    template <typename OutputByteStream>
    static void PutBOM(OutputByteStream& os)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>(0xFEu));
        os.Put(static_cast<typename OutputByteStream::Ch>(0x00u));
        os.Put(static_cast<typename OutputByteStream::Ch>(0x00u));
    }
 
    template <typename OutputByteStream>
    static void Put(OutputByteStream& os, CharType c)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(c & 0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>((c >> 8) & 0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>((c >> 16) & 0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>((c >> 24) & 0xFFu));
    }
};
template <typename CharType = unsigned>
struct UTF32BE : UTF32<CharType>
{
    template <typename InputByteStream>
    static CharType TakeBOM(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        CharType c = Take(is);
        return static_cast<uint32_t>(c) == 0x0000FEFFu ? Take(is) : c;
    }
 
    template <typename InputByteStream>
    static CharType Take(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        unsigned c = static_cast<unsigned>(static_cast<uint8_t>(is.Take())) << 24;
        c |= static_cast<unsigned>(static_cast<uint8_t>(is.Take())) << 16;
        c |= static_cast<unsigned>(static_cast<uint8_t>(is.Take())) << 8;
        c |= static_cast<unsigned>(static_cast<uint8_t>(is.Take()));
        return static_cast<CharType>(c);
    }
 
    template <typename OutputByteStream>
    static void PutBOM(OutputByteStream& os)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(0x00u));
        os.Put(static_cast<typename OutputByteStream::Ch>(0x00u));
        os.Put(static_cast<typename OutputByteStream::Ch>(0xFEu));
        os.Put(static_cast<typename OutputByteStream::Ch>(0xFFu));
    }
 
    template <typename OutputByteStream>
    static void Put(OutputByteStream& os, CharType c)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>((c >> 24) & 0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>((c >> 16) & 0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>((c >> 8) & 0xFFu));
        os.Put(static_cast<typename OutputByteStream::Ch>(c & 0xFFu));
    }
};
// ASCII
template <typename CharType = char>
struct ASCII
{
    typedef CharType Ch;
 
    enum
    {
        supportUnicode = 0
    };
 
    template <typename OutputStream>
    static void Encode(OutputStream& os, unsigned codepoint)
    {
        RAPIDJSON_ASSERT(codepoint <= 0x7F);
        os.Put(static_cast<Ch>(codepoint & 0xFF));
    }
 
    template <typename OutputStream>
    static void EncodeUnsafe(OutputStream& os, unsigned codepoint)
    {
        RAPIDJSON_ASSERT(codepoint <= 0x7F);
        PutUnsafe(os, static_cast<Ch>(codepoint & 0xFF));
    }
 
    template <typename InputStream>
    static bool Decode(InputStream& is, unsigned* codepoint)
    {
        uint8_t c  = static_cast<uint8_t>(is.Take());
        *codepoint = c;
        return c <= 0X7F;
    }
 
    template <typename InputStream, typename OutputStream>
    static bool Validate(InputStream& is, OutputStream& os)
    {
        uint8_t c = static_cast<uint8_t>(is.Take());
        os.Put(static_cast<typename OutputStream::Ch>(c));
        return c <= 0x7F;
    }
 
    template <typename InputByteStream>
    static CharType TakeBOM(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        uint8_t c = static_cast<uint8_t>(Take(is));
        return static_cast<Ch>(c);
    }
 
    template <typename InputByteStream>
    static Ch Take(InputByteStream& is)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
        return static_cast<Ch>(is.Take());
    }
 
    template <typename OutputByteStream>
    static void PutBOM(OutputByteStream& os)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        (void)os;
    }
 
    template <typename OutputByteStream>
    static void Put(OutputByteStream& os, Ch c)
    {
        RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
        os.Put(static_cast<typename OutputByteStream::Ch>(c));
    }
};
// AutoUTF
enum UTFType
{
    kUTF8    = 0, 
    kUTF16LE = 1, 
    kUTF16BE = 2, 
    kUTF32LE = 3, 
    kUTF32BE = 4  
};
template <typename CharType>
struct AutoUTF
{
    typedef CharType Ch;
 
    enum
    {
        supportUnicode = 1
    };
 
#define RAPIDJSON_ENCODINGS_FUNC(x) \
    UTF8<Ch>::x, UTF16LE<Ch>::x, UTF16BE<Ch>::x, UTF32LE<Ch>::x, UTF32BE<Ch>::x
 
    template <typename OutputStream>
    static RAPIDJSON_FORCEINLINE void Encode(OutputStream& os, unsigned codepoint)
    {
        typedef void (*EncodeFunc)(OutputStream&, unsigned);
        static const EncodeFunc f[] = {RAPIDJSON_ENCODINGS_FUNC(Encode)};
        (*f[os.GetType()])(os, codepoint);
    }
 
    template <typename OutputStream>
    static RAPIDJSON_FORCEINLINE void EncodeUnsafe(OutputStream& os, unsigned codepoint)
    {
        typedef void (*EncodeFunc)(OutputStream&, unsigned);
        static const EncodeFunc f[] = {RAPIDJSON_ENCODINGS_FUNC(EncodeUnsafe)};
        (*f[os.GetType()])(os, codepoint);
    }
 
    template <typename InputStream>
    static RAPIDJSON_FORCEINLINE bool Decode(InputStream& is, unsigned* codepoint)
    {
        typedef bool (*DecodeFunc)(InputStream&, unsigned*);
        static const DecodeFunc f[] = {RAPIDJSON_ENCODINGS_FUNC(Decode)};
        return (*f[is.GetType()])(is, codepoint);
    }
 
    template <typename InputStream, typename OutputStream>
    static RAPIDJSON_FORCEINLINE bool Validate(InputStream& is, OutputStream& os)
    {
        typedef bool (*ValidateFunc)(InputStream&, OutputStream&);
        static const ValidateFunc f[] = {RAPIDJSON_ENCODINGS_FUNC(Validate)};
        return (*f[is.GetType()])(is, os);
    }
 
#undef RAPIDJSON_ENCODINGS_FUNC
};
// Transcoder
template <typename SourceEncoding, typename TargetEncoding>
struct Transcoder
{
    template <typename InputStream, typename OutputStream>
    static RAPIDJSON_FORCEINLINE bool Transcode(InputStream& is, OutputStream& os)
    {
        unsigned codepoint;
        if(!SourceEncoding::Decode(is, &codepoint))
            return false;
        TargetEncoding::Encode(os, codepoint);
        return true;
    }
 
    template <typename InputStream, typename OutputStream>
    static RAPIDJSON_FORCEINLINE bool TranscodeUnsafe(InputStream& is, OutputStream& os)
    {
        unsigned codepoint;
        if(!SourceEncoding::Decode(is, &codepoint))
            return false;
        TargetEncoding::EncodeUnsafe(os, codepoint);
        return true;
    }
    template <typename InputStream, typename OutputStream>
    static RAPIDJSON_FORCEINLINE bool Validate(InputStream& is, OutputStream& os)
    {
        return Transcode(is, os); // Since source/target encoding is different, must transcode.
    }
};
 
// Forward declaration.
template <typename Stream>
inline void PutUnsafe(Stream& stream, typename Stream::Ch c);
template <typename Encoding>
struct Transcoder<Encoding, Encoding>
{
    template <typename InputStream, typename OutputStream>
    static RAPIDJSON_FORCEINLINE bool Transcode(InputStream& is, OutputStream& os)
    {
        os.Put(is.Take()); // Just copy one code unit. This semantic is different from primary
                           // template class.
        return true;
    }
 
    template <typename InputStream, typename OutputStream>
    static RAPIDJSON_FORCEINLINE bool TranscodeUnsafe(InputStream& is, OutputStream& os)
    {
        PutUnsafe(os, is.Take()); // Just copy one code unit. This semantic is different from
                                  // primary template class.
        return true;
    }
 
    template <typename InputStream, typename OutputStream>
    static RAPIDJSON_FORCEINLINE bool Validate(InputStream& is, OutputStream& os)
    {
        return Encoding::Validate(is, os); // source/target encoding are the same
    }
};
 
RAPIDJSON_NAMESPACE_END
 
#if defined(__GNUC__) || (defined(_MSC_VER) && !defined(__clang__))
RAPIDJSON_DIAG_POP
#endif
 
#endif // RAPIDJSON_ENCODINGS_H_