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 // 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_WRITER_H_
 #define RAPIDJSON_WRITER_H_
  
 #include "stream.h"
 #include "internal/clzll.h"
 #include "internal/meta.h"
 #include "internal/stack.h"
 #include "internal/strfunc.h"
 #include "internal/dtoa.h"
 #include "internal/itoa.h"
 #include "stringbuffer.h"
 #include <new>      // placement new
  
 #if defined(RAPIDJSON_SIMD) && defined(_MSC_VER)
 #include <intrin.h>
 #pragma intrinsic(_BitScanForward)
 #endif
 #ifdef RAPIDJSON_SSE42
 #include <nmmintrin.h>
 #elif defined(RAPIDJSON_SSE2)
 #include <emmintrin.h>
 #elif defined(RAPIDJSON_NEON)
 #include <arm_neon.h>
 #endif
  
 #ifdef __clang__
 RAPIDJSON_DIAG_PUSH
 RAPIDJSON_DIAG_OFF(padded)
 RAPIDJSON_DIAG_OFF(unreachable-code)
 RAPIDJSON_DIAG_OFF(c++98-compat)
 #elif defined(_MSC_VER)
 RAPIDJSON_DIAG_PUSH
 RAPIDJSON_DIAG_OFF(4127) // conditional expression is constant
 #endif
  
 RAPIDJSON_NAMESPACE_BEGIN
  
 // WriteFlag
  
 #ifndef RAPIDJSON_WRITE_DEFAULT_FLAGS
 #define RAPIDJSON_WRITE_DEFAULT_FLAGS kWriteNoFlags
 #endif
  
 enum WriteFlag {
     kWriteNoFlags = 0,              
     kWriteValidateEncodingFlag = 1, 
     kWriteNanAndInfFlag = 2,        
     kWriteNanAndInfNullFlag = 4,    
     kWriteDefaultFlags = RAPIDJSON_WRITE_DEFAULT_FLAGS  
 };
  
  
 template<typename OutputStream, typename SourceEncoding = UTF8<>, typename TargetEncoding = UTF8<>, typename StackAllocator = CrtAllocator, unsigned writeFlags = kWriteDefaultFlags>
 class Writer {
 public:
     typedef typename SourceEncoding::Ch Ch;
  
     static const int kDefaultMaxDecimalPlaces = 324;
  
  
     explicit
     Writer(OutputStream& os, StackAllocator* stackAllocator = 0, size_t levelDepth = kDefaultLevelDepth) : 
         os_(&os), level_stack_(stackAllocator, levelDepth * sizeof(Level)), maxDecimalPlaces_(kDefaultMaxDecimalPlaces), hasRoot_(false) {}
  
     explicit
     Writer(StackAllocator* allocator = 0, size_t levelDepth = kDefaultLevelDepth) :
         os_(0), level_stack_(allocator, levelDepth * sizeof(Level)), maxDecimalPlaces_(kDefaultMaxDecimalPlaces), hasRoot_(false) {}
  
 #if RAPIDJSON_HAS_CXX11_RVALUE_REFS
     Writer(Writer&& rhs) :
         os_(rhs.os_), level_stack_(std::move(rhs.level_stack_)), maxDecimalPlaces_(rhs.maxDecimalPlaces_), hasRoot_(rhs.hasRoot_) {
         rhs.os_ = 0;
     }
 #endif
  
  
     void Reset(OutputStream& os) {
         os_ = &os;
         hasRoot_ = false;
         level_stack_.Clear();
     }
  
  
     bool IsComplete() const {
         return hasRoot_ && level_stack_.Empty();
     }
  
     int GetMaxDecimalPlaces() const {
         return maxDecimalPlaces_;
     }
  
  
     void SetMaxDecimalPlaces(int maxDecimalPlaces) {
         maxDecimalPlaces_ = maxDecimalPlaces;
     }
  
  
     bool Null()                 { Prefix(kNullType);   return EndValue(WriteNull()); }
     bool Bool(bool b)           { Prefix(b ? kTrueType : kFalseType); return EndValue(WriteBool(b)); }
     bool Int(int i)             { Prefix(kNumberType); return EndValue(WriteInt(i)); }
     bool Uint(unsigned u)       { Prefix(kNumberType); return EndValue(WriteUint(u)); }
     bool Int64(int64_t i64)     { Prefix(kNumberType); return EndValue(WriteInt64(i64)); }
     bool Uint64(uint64_t u64)   { Prefix(kNumberType); return EndValue(WriteUint64(u64)); }
  
  
     bool Double(double d)       { Prefix(kNumberType); return EndValue(WriteDouble(d)); }
  
     bool RawNumber(const Ch* str, SizeType length, bool copy = false) {
         RAPIDJSON_ASSERT(str != 0);
         (void)copy;
         Prefix(kNumberType);
         return EndValue(WriteString(str, length));
     }
  
     bool String(const Ch* str, SizeType length, bool copy = false) {
         RAPIDJSON_ASSERT(str != 0);
         (void)copy;
         Prefix(kStringType);
         return EndValue(WriteString(str, length));
     }
  
 #if RAPIDJSON_HAS_STDSTRING
     bool String(const std::basic_string<Ch>& str) {
         return String(str.data(), SizeType(str.size()));
     }
 #endif
  
     bool StartObject() {
         Prefix(kObjectType);
         new (level_stack_.template Push<Level>()) Level(false);
         return WriteStartObject();
     }
  
     bool Key(const Ch* str, SizeType length, bool copy = false) { return String(str, length, copy); }
  
 #if RAPIDJSON_HAS_STDSTRING
     bool Key(const std::basic_string<Ch>& str)
     {
       return Key(str.data(), SizeType(str.size()));
     }
 #endif
  
     bool EndObject(SizeType memberCount = 0) {
         (void)memberCount;
         RAPIDJSON_ASSERT(level_stack_.GetSize() >= sizeof(Level)); // not inside an Object
         RAPIDJSON_ASSERT(!level_stack_.template Top<Level>()->inArray); // currently inside an Array, not Object
         RAPIDJSON_ASSERT(0 == level_stack_.template Top<Level>()->valueCount % 2); // Object has a Key without a Value
         level_stack_.template Pop<Level>(1);
         return EndValue(WriteEndObject());
     }
  
     bool StartArray() {
         Prefix(kArrayType);
         new (level_stack_.template Push<Level>()) Level(true);
         return WriteStartArray();
     }
  
     bool EndArray(SizeType elementCount = 0) {
         (void)elementCount;
         RAPIDJSON_ASSERT(level_stack_.GetSize() >= sizeof(Level));
         RAPIDJSON_ASSERT(level_stack_.template Top<Level>()->inArray);
         level_stack_.template Pop<Level>(1);
         return EndValue(WriteEndArray());
     }
  
  
     bool String(const Ch* const& str) { return String(str, internal::StrLen(str)); }
     bool Key(const Ch* const& str) { return Key(str, internal::StrLen(str)); }
     
  
  
     bool RawValue(const Ch* json, size_t length, Type type) {
         RAPIDJSON_ASSERT(json != 0);
         Prefix(type);
         return EndValue(WriteRawValue(json, length));
     }
  
  
     void Flush() {
         os_->Flush();
     }
  
     static const size_t kDefaultLevelDepth = 32;
  
 protected:
     struct Level {
         Level(bool inArray_) : valueCount(0), inArray(inArray_) {}
         size_t valueCount;  
         bool inArray;       
     };
  
     bool WriteNull()  {
         PutReserve(*os_, 4);
         PutUnsafe(*os_, 'n'); PutUnsafe(*os_, 'u'); PutUnsafe(*os_, 'l'); PutUnsafe(*os_, 'l'); return true;
     }
  
     bool WriteBool(bool b)  {
         if (b) {
             PutReserve(*os_, 4);
             PutUnsafe(*os_, 't'); PutUnsafe(*os_, 'r'); PutUnsafe(*os_, 'u'); PutUnsafe(*os_, 'e');
         }
         else {
             PutReserve(*os_, 5);
             PutUnsafe(*os_, 'f'); PutUnsafe(*os_, 'a'); PutUnsafe(*os_, 'l'); PutUnsafe(*os_, 's'); PutUnsafe(*os_, 'e');
         }
         return true;
     }
  
     bool WriteInt(int i) {
         char buffer[11];
         const char* end = internal::i32toa(i, buffer);
         PutReserve(*os_, static_cast<size_t>(end - buffer));
         for (const char* p = buffer; p != end; ++p)
             PutUnsafe(*os_, static_cast<typename OutputStream::Ch>(*p));
         return true;
     }
  
     bool WriteUint(unsigned u) {
         char buffer[10];
         const char* end = internal::u32toa(u, buffer);
         PutReserve(*os_, static_cast<size_t>(end - buffer));
         for (const char* p = buffer; p != end; ++p)
             PutUnsafe(*os_, static_cast<typename OutputStream::Ch>(*p));
         return true;
     }
  
     bool WriteInt64(int64_t i64) {
         char buffer[21];
         const char* end = internal::i64toa(i64, buffer);
         PutReserve(*os_, static_cast<size_t>(end - buffer));
         for (const char* p = buffer; p != end; ++p)
             PutUnsafe(*os_, static_cast<typename OutputStream::Ch>(*p));
         return true;
     }
  
     bool WriteUint64(uint64_t u64) {
         char buffer[20];
         char* end = internal::u64toa(u64, buffer);
         PutReserve(*os_, static_cast<size_t>(end - buffer));
         for (char* p = buffer; p != end; ++p)
             PutUnsafe(*os_, static_cast<typename OutputStream::Ch>(*p));
         return true;
     }
  
     bool WriteDouble(double d) {
         if (internal::Double(d).IsNanOrInf()) {
             if (!(writeFlags & kWriteNanAndInfFlag) && !(writeFlags & kWriteNanAndInfNullFlag))
                 return false;
             if (writeFlags & kWriteNanAndInfNullFlag) {
                 PutReserve(*os_, 4);
                 PutUnsafe(*os_, 'n'); PutUnsafe(*os_, 'u'); PutUnsafe(*os_, 'l'); PutUnsafe(*os_, 'l');
                 return true;
             }
             if (internal::Double(d).IsNan()) {
                 PutReserve(*os_, 3);
                 PutUnsafe(*os_, 'N'); PutUnsafe(*os_, 'a'); PutUnsafe(*os_, 'N');
                 return true;
             }
             if (internal::Double(d).Sign()) {
                 PutReserve(*os_, 9);
                 PutUnsafe(*os_, '-');
             }
             else
                 PutReserve(*os_, 8);
             PutUnsafe(*os_, 'I'); PutUnsafe(*os_, 'n'); PutUnsafe(*os_, 'f');
             PutUnsafe(*os_, 'i'); PutUnsafe(*os_, 'n'); PutUnsafe(*os_, 'i'); PutUnsafe(*os_, 't'); PutUnsafe(*os_, 'y');
             return true;
         }
  
         char buffer[25];
         char* end = internal::dtoa(d, buffer, maxDecimalPlaces_);
         PutReserve(*os_, static_cast<size_t>(end - buffer));
         for (char* p = buffer; p != end; ++p)
             PutUnsafe(*os_, static_cast<typename OutputStream::Ch>(*p));
         return true;
     }
  
     bool WriteString(const Ch* str, SizeType length)  {
         static const typename OutputStream::Ch hexDigits[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
         static const char escape[256] = {
 #define Z16 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
             //0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F
             'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'b', 't', 'n', 'u', 'f', 'r', 'u', 'u', // 00
             'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', // 10
               0,   0, '"',   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, // 20
             Z16, Z16,                                                                       // 30~4F
               0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,'\\',   0,   0,   0, // 50
             Z16, Z16, Z16, Z16, Z16, Z16, Z16, Z16, Z16, Z16                                // 60~FF
 #undef Z16
         };
  
         if (TargetEncoding::supportUnicode)
             PutReserve(*os_, 2 + length * 6); // "\uxxxx..."
         else
             PutReserve(*os_, 2 + length * 12);  // "\uxxxx\uyyyy..."
  
         PutUnsafe(*os_, '\"');
         GenericStringStream<SourceEncoding> is(str);
         while (ScanWriteUnescapedString(is, length)) {
             const Ch c = is.Peek();
             if (!TargetEncoding::supportUnicode && static_cast<unsigned>(c) >= 0x80) {
                 // Unicode escaping
                 unsigned codepoint;
                 if (RAPIDJSON_UNLIKELY(!SourceEncoding::Decode(is, &codepoint)))
                     return false;
                 PutUnsafe(*os_, '\\');
                 PutUnsafe(*os_, 'u');
                 if (codepoint <= 0xD7FF || (codepoint >= 0xE000 && codepoint <= 0xFFFF)) {
                     PutUnsafe(*os_, hexDigits[(codepoint >> 12) & 15]);
                     PutUnsafe(*os_, hexDigits[(codepoint >>  8) & 15]);
                     PutUnsafe(*os_, hexDigits[(codepoint >>  4) & 15]);
                     PutUnsafe(*os_, hexDigits[(codepoint      ) & 15]);
                 }
                 else {
                     RAPIDJSON_ASSERT(codepoint >= 0x010000 && codepoint <= 0x10FFFF);
                     // Surrogate pair
                     unsigned s = codepoint - 0x010000;
                     unsigned lead = (s >> 10) + 0xD800;
                     unsigned trail = (s & 0x3FF) + 0xDC00;
                     PutUnsafe(*os_, hexDigits[(lead >> 12) & 15]);
                     PutUnsafe(*os_, hexDigits[(lead >>  8) & 15]);
                     PutUnsafe(*os_, hexDigits[(lead >>  4) & 15]);
                     PutUnsafe(*os_, hexDigits[(lead      ) & 15]);
                     PutUnsafe(*os_, '\\');
                     PutUnsafe(*os_, 'u');
                     PutUnsafe(*os_, hexDigits[(trail >> 12) & 15]);
                     PutUnsafe(*os_, hexDigits[(trail >>  8) & 15]);
                     PutUnsafe(*os_, hexDigits[(trail >>  4) & 15]);
                     PutUnsafe(*os_, hexDigits[(trail      ) & 15]);                    
                 }
             }
             else if ((sizeof(Ch) == 1 || static_cast<unsigned>(c) < 256) && RAPIDJSON_UNLIKELY(escape[static_cast<unsigned char>(c)]))  {
                 is.Take();
                 PutUnsafe(*os_, '\\');
                 PutUnsafe(*os_, static_cast<typename OutputStream::Ch>(escape[static_cast<unsigned char>(c)]));
                 if (escape[static_cast<unsigned char>(c)] == 'u') {
                     PutUnsafe(*os_, '0');
                     PutUnsafe(*os_, '0');
                     PutUnsafe(*os_, hexDigits[static_cast<unsigned char>(c) >> 4]);
                     PutUnsafe(*os_, hexDigits[static_cast<unsigned char>(c) & 0xF]);
                 }
             }
             else if (RAPIDJSON_UNLIKELY(!(writeFlags & kWriteValidateEncodingFlag ? 
                 Transcoder<SourceEncoding, TargetEncoding>::Validate(is, *os_) :
                 Transcoder<SourceEncoding, TargetEncoding>::TranscodeUnsafe(is, *os_))))
                 return false;
         }
         PutUnsafe(*os_, '\"');
         return true;
     }
  
     bool ScanWriteUnescapedString(GenericStringStream<SourceEncoding>& is, size_t length) {
         return RAPIDJSON_LIKELY(is.Tell() < length);
     }
  
     bool WriteStartObject() { os_->Put('{'); return true; }
     bool WriteEndObject()   { os_->Put('}'); return true; }
     bool WriteStartArray()  { os_->Put('['); return true; }
     bool WriteEndArray()    { os_->Put(']'); return true; }
  
     bool WriteRawValue(const Ch* json, size_t length) {
         PutReserve(*os_, length);
         GenericStringStream<SourceEncoding> is(json);
         while (RAPIDJSON_LIKELY(is.Tell() < length)) {
             RAPIDJSON_ASSERT(is.Peek() != '\0');
             if (RAPIDJSON_UNLIKELY(!(writeFlags & kWriteValidateEncodingFlag ? 
                 Transcoder<SourceEncoding, TargetEncoding>::Validate(is, *os_) :
                 Transcoder<SourceEncoding, TargetEncoding>::TranscodeUnsafe(is, *os_))))
                 return false;
         }
         return true;
     }
  
     void Prefix(Type type) {
         (void)type;
         if (RAPIDJSON_LIKELY(level_stack_.GetSize() != 0)) { // this value is not at root
             Level* level = level_stack_.template Top<Level>();
             if (level->valueCount > 0) {
                 if (level->inArray) 
                     os_->Put(','); // add comma if it is not the first element in array
                 else  // in object
                     os_->Put((level->valueCount % 2 == 0) ? ',' : ':');
             }
             if (!level->inArray && level->valueCount % 2 == 0)
                 RAPIDJSON_ASSERT(type == kStringType);  // if it's in object, then even number should be a name
             level->valueCount++;
         }
         else {
             RAPIDJSON_ASSERT(!hasRoot_);    // Should only has one and only one root.
             hasRoot_ = true;
         }
     }
  
     // Flush the value if it is the top level one.
     bool EndValue(bool ret) {
         if (RAPIDJSON_UNLIKELY(level_stack_.Empty()))   // end of json text
             Flush();
         return ret;
     }
  
     OutputStream* os_;
     internal::Stack<StackAllocator> level_stack_;
     int maxDecimalPlaces_;
     bool hasRoot_;
  
 private:
     // Prohibit copy constructor & assignment operator.
     Writer(const Writer&);
     Writer& operator=(const Writer&);
 };
  
 // Full specialization for StringStream to prevent memory copying
  
 template<>
 inline bool Writer<StringBuffer>::WriteInt(int i) {
     char *buffer = os_->Push(11);
     const char* end = internal::i32toa(i, buffer);
     os_->Pop(static_cast<size_t>(11 - (end - buffer)));
     return true;
 }
  
 template<>
 inline bool Writer<StringBuffer>::WriteUint(unsigned u) {
     char *buffer = os_->Push(10);
     const char* end = internal::u32toa(u, buffer);
     os_->Pop(static_cast<size_t>(10 - (end - buffer)));
     return true;
 }
  
 template<>
 inline bool Writer<StringBuffer>::WriteInt64(int64_t i64) {
     char *buffer = os_->Push(21);
     const char* end = internal::i64toa(i64, buffer);
     os_->Pop(static_cast<size_t>(21 - (end - buffer)));
     return true;
 }
  
 template<>
 inline bool Writer<StringBuffer>::WriteUint64(uint64_t u) {
     char *buffer = os_->Push(20);
     const char* end = internal::u64toa(u, buffer);
     os_->Pop(static_cast<size_t>(20 - (end - buffer)));
     return true;
 }
  
 template<>
 inline bool Writer<StringBuffer>::WriteDouble(double d) {
     if (internal::Double(d).IsNanOrInf()) {
         // Note: This code path can only be reached if (RAPIDJSON_WRITE_DEFAULT_FLAGS & kWriteNanAndInfFlag).
         if (!(kWriteDefaultFlags & kWriteNanAndInfFlag))
             return false;
         if (kWriteDefaultFlags & kWriteNanAndInfNullFlag) {
             PutReserve(*os_, 4);
             PutUnsafe(*os_, 'n'); PutUnsafe(*os_, 'u'); PutUnsafe(*os_, 'l'); PutUnsafe(*os_, 'l');
             return true;
         }
         if (internal::Double(d).IsNan()) {
             PutReserve(*os_, 3);
             PutUnsafe(*os_, 'N'); PutUnsafe(*os_, 'a'); PutUnsafe(*os_, 'N');
             return true;
         }
         if (internal::Double(d).Sign()) {
             PutReserve(*os_, 9);
             PutUnsafe(*os_, '-');
         }
         else
             PutReserve(*os_, 8);
         PutUnsafe(*os_, 'I'); PutUnsafe(*os_, 'n'); PutUnsafe(*os_, 'f');
         PutUnsafe(*os_, 'i'); PutUnsafe(*os_, 'n'); PutUnsafe(*os_, 'i'); PutUnsafe(*os_, 't'); PutUnsafe(*os_, 'y');
         return true;
     }
     
     char *buffer = os_->Push(25);
     char* end = internal::dtoa(d, buffer, maxDecimalPlaces_);
     os_->Pop(static_cast<size_t>(25 - (end - buffer)));
     return true;
 }
  
 #if defined(RAPIDJSON_SSE2) || defined(RAPIDJSON_SSE42)
 template<>
 inline bool Writer<StringBuffer>::ScanWriteUnescapedString(StringStream& is, size_t length) {
     if (length < 16)
         return RAPIDJSON_LIKELY(is.Tell() < length);
  
     if (!RAPIDJSON_LIKELY(is.Tell() < length))
         return false;
  
     const char* p = is.src_;
     const char* end = is.head_ + length;
     const char* nextAligned = reinterpret_cast<const char*>((reinterpret_cast<size_t>(p) + 15) & static_cast<size_t>(~15));
     const char* endAligned = reinterpret_cast<const char*>(reinterpret_cast<size_t>(end) & static_cast<size_t>(~15));
     if (nextAligned > end)
         return true;
  
     while (p != nextAligned)
         if (*p < 0x20 || *p == '\"' || *p == '\\') {
             is.src_ = p;
             return RAPIDJSON_LIKELY(is.Tell() < length);
         }
         else
             os_->PutUnsafe(*p++);
  
     // The rest of string using SIMD
     static const char dquote[16] = { '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"' };
     static const char bslash[16] = { '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\' };
     static const char space[16]  = { 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F };
     const __m128i dq = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&dquote[0]));
     const __m128i bs = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&bslash[0]));
     const __m128i sp = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&space[0]));
  
     for (; p != endAligned; p += 16) {
         const __m128i s = _mm_load_si128(reinterpret_cast<const __m128i *>(p));
         const __m128i t1 = _mm_cmpeq_epi8(s, dq);
         const __m128i t2 = _mm_cmpeq_epi8(s, bs);
         const __m128i t3 = _mm_cmpeq_epi8(_mm_max_epu8(s, sp), sp); // s < 0x20 <=> max(s, 0x1F) == 0x1F
         const __m128i x = _mm_or_si128(_mm_or_si128(t1, t2), t3);
         unsigned short r = static_cast<unsigned short>(_mm_movemask_epi8(x));
         if (RAPIDJSON_UNLIKELY(r != 0)) {   // some of characters is escaped
             SizeType len;
 #ifdef _MSC_VER         // Find the index of first escaped
             unsigned long offset;
             _BitScanForward(&offset, r);
             len = offset;
 #else
             len = static_cast<SizeType>(__builtin_ffs(r) - 1);
 #endif
             char* q = reinterpret_cast<char*>(os_->PushUnsafe(len));
             for (size_t i = 0; i < len; i++)
                 q[i] = p[i];
  
             p += len;
             break;
         }
         _mm_storeu_si128(reinterpret_cast<__m128i *>(os_->PushUnsafe(16)), s);
     }
  
     is.src_ = p;
     return RAPIDJSON_LIKELY(is.Tell() < length);
 }
 #elif defined(RAPIDJSON_NEON)
 template<>
 inline bool Writer<StringBuffer>::ScanWriteUnescapedString(StringStream& is, size_t length) {
     if (length < 16)
         return RAPIDJSON_LIKELY(is.Tell() < length);
  
     if (!RAPIDJSON_LIKELY(is.Tell() < length))
         return false;
  
     const char* p = is.src_;
     const char* end = is.head_ + length;
     const char* nextAligned = reinterpret_cast<const char*>((reinterpret_cast<size_t>(p) + 15) & static_cast<size_t>(~15));
     const char* endAligned = reinterpret_cast<const char*>(reinterpret_cast<size_t>(end) & static_cast<size_t>(~15));
     if (nextAligned > end)
         return true;
  
     while (p != nextAligned)
         if (*p < 0x20 || *p == '\"' || *p == '\\') {
             is.src_ = p;
             return RAPIDJSON_LIKELY(is.Tell() < length);
         }
         else
             os_->PutUnsafe(*p++);
  
     // The rest of string using SIMD
     const uint8x16_t s0 = vmovq_n_u8('"');
     const uint8x16_t s1 = vmovq_n_u8('\\');
     const uint8x16_t s2 = vmovq_n_u8('\b');
     const uint8x16_t s3 = vmovq_n_u8(32);
  
     for (; p != endAligned; p += 16) {
         const uint8x16_t s = vld1q_u8(reinterpret_cast<const uint8_t *>(p));
         uint8x16_t x = vceqq_u8(s, s0);
         x = vorrq_u8(x, vceqq_u8(s, s1));
         x = vorrq_u8(x, vceqq_u8(s, s2));
         x = vorrq_u8(x, vcltq_u8(s, s3));
  
         x = vrev64q_u8(x);                     // Rev in 64
         uint64_t low = vgetq_lane_u64(vreinterpretq_u64_u8(x), 0);   // extract
         uint64_t high = vgetq_lane_u64(vreinterpretq_u64_u8(x), 1);  // extract
  
         SizeType len = 0;
         bool escaped = false;
         if (low == 0) {
             if (high != 0) {
                 uint32_t lz = internal::clzll(high);
                 len = 8 + (lz >> 3);
                 escaped = true;
             }
         } else {
             uint32_t lz = internal::clzll(low);
             len = lz >> 3;
             escaped = true;
         }
         if (RAPIDJSON_UNLIKELY(escaped)) {   // some of characters is escaped
             char* q = reinterpret_cast<char*>(os_->PushUnsafe(len));
             for (size_t i = 0; i < len; i++)
                 q[i] = p[i];
  
             p += len;
             break;
         }
         vst1q_u8(reinterpret_cast<uint8_t *>(os_->PushUnsafe(16)), s);
     }
  
     is.src_ = p;
     return RAPIDJSON_LIKELY(is.Tell() < length);
 }
 #endif // RAPIDJSON_NEON
  
 RAPIDJSON_NAMESPACE_END
  
 #if defined(_MSC_VER) || defined(__clang__)
 RAPIDJSON_DIAG_POP
 #endif
  
 #endif // RAPIDJSON_RAPIDJSON_H_