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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. All rights reserved.
- //
- // 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 "rapidjson.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 RAPIDJSON_HAS_STDSTRING
- #include <string>
- #endif
- #ifdef _MSC_VER
- RAPIDJSON_DIAG_PUSH
- RAPIDJSON_DIAG_OFF(4127) // conditional expression is constant
- #endif
- RAPIDJSON_NAMESPACE_BEGIN
- //! JSON writer
- /*! Writer implements the concept Handler.
- It generates JSON text by events to an output os.
- User may programmatically calls the functions of a writer to generate JSON text.
- On the other side, a writer can also be passed to objects that generates events,
- for example Reader::Parse() and Document::Accept().
- \tparam OutputStream Type of output stream.
- \tparam SourceEncoding Encoding of source string.
- \tparam TargetEncoding Encoding of output stream.
- \tparam StackAllocator Type of allocator for allocating memory of stack.
- \note implements Handler concept
- */
- template<typename OutputStream, typename SourceEncoding = UTF8<>, typename TargetEncoding = UTF8<>, typename StackAllocator = CrtAllocator>
- class Writer {
- public:
- typedef typename SourceEncoding::Ch Ch;
- //! Constructor
- /*! \param os Output stream.
- \param stackAllocator User supplied allocator. If it is null, it will create a private one.
- \param levelDepth Initial capacity of stack.
- */
- explicit
- Writer(OutputStream& os, StackAllocator* stackAllocator = 0, size_t levelDepth = kDefaultLevelDepth) :
- os_(&os), level_stack_(stackAllocator, levelDepth * sizeof(Level)), hasRoot_(false) {}
- explicit
- Writer(StackAllocator* allocator = 0, size_t levelDepth = kDefaultLevelDepth) :
- os_(0), level_stack_(allocator, levelDepth * sizeof(Level)), hasRoot_(false) {}
- //! Reset the writer with a new stream.
- /*!
- This function reset the writer with a new stream and default settings,
- in order to make a Writer object reusable for output multiple JSONs.
- \param os New output stream.
- \code
- Writer<OutputStream> writer(os1);
- writer.StartObject();
- // ...
- writer.EndObject();
- writer.Reset(os2);
- writer.StartObject();
- // ...
- writer.EndObject();
- \endcode
- */
- void Reset(OutputStream& os) {
- os_ = &os;
- hasRoot_ = false;
- level_stack_.Clear();
- }
- //! Checks whether the output is a complete JSON.
- /*!
- A complete JSON has a complete root object or array.
- */
- bool IsComplete() const {
- return hasRoot_ && level_stack_.Empty();
- }
- /*!@name Implementation of Handler
- \see Handler
- */
- //@{
- bool Null() { Prefix(kNullType); return WriteNull(); }
- bool Bool(bool b) { Prefix(b ? kTrueType : kFalseType); return WriteBool(b); }
- bool Int(int i) { Prefix(kNumberType); return WriteInt(i); }
- bool Uint(unsigned u) { Prefix(kNumberType); return WriteUint(u); }
- bool Int64(int64_t i64) { Prefix(kNumberType); return WriteInt64(i64); }
- bool Uint64(uint64_t u64) { Prefix(kNumberType); return WriteUint64(u64); }
- //! Writes the given \c double value to the stream
- /*!
- \param d The value to be written.
- \return Whether it is succeed.
- */
- bool Double(double d) { Prefix(kNumberType); return WriteDouble(d); }
- bool String(const Ch* str, SizeType length, bool copy = false) {
- (void)copy;
- Prefix(kStringType);
- return 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); }
-
- bool EndObject(SizeType memberCount = 0) {
- (void)memberCount;
- RAPIDJSON_ASSERT(level_stack_.GetSize() >= sizeof(Level));
- RAPIDJSON_ASSERT(!level_stack_.template Top<Level>()->inArray);
- level_stack_.template Pop<Level>(1);
- bool ret = WriteEndObject();
- if (level_stack_.Empty()) // end of json text
- os_->Flush();
- return ret;
- }
- 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);
- bool ret = WriteEndArray();
- if (level_stack_.Empty()) // end of json text
- os_->Flush();
- return ret;
- }
- //@}
- /*! @name Convenience extensions */
- //@{
- //! Simpler but slower overload.
- bool String(const Ch* str) { return String(str, internal::StrLen(str)); }
- bool Key(const Ch* str) { return Key(str, internal::StrLen(str)); }
- //@}
- protected:
- //! Information for each nested level
- struct Level {
- Level(bool inArray_) : valueCount(0), inArray(inArray_) {}
- size_t valueCount; //!< number of values in this level
- bool inArray; //!< true if in array, otherwise in object
- };
- static const size_t kDefaultLevelDepth = 32;
- bool WriteNull() {
- os_->Put('n'); os_->Put('u'); os_->Put('l'); os_->Put('l'); return true;
- }
- bool WriteBool(bool b) {
- if (b) {
- os_->Put('t'); os_->Put('r'); os_->Put('u'); os_->Put('e');
- }
- else {
- os_->Put('f'); os_->Put('a'); os_->Put('l'); os_->Put('s'); os_->Put('e');
- }
- return true;
- }
- bool WriteInt(int i) {
- char buffer[11];
- const char* end = internal::i32toa(i, buffer);
- for (const char* p = buffer; p != end; ++p)
- os_->Put(*p);
- return true;
- }
- bool WriteUint(unsigned u) {
- char buffer[10];
- const char* end = internal::u32toa(u, buffer);
- for (const char* p = buffer; p != end; ++p)
- os_->Put(*p);
- return true;
- }
- bool WriteInt64(int64_t i64) {
- char buffer[21];
- const char* end = internal::i64toa(i64, buffer);
- for (const char* p = buffer; p != end; ++p)
- os_->Put(*p);
- return true;
- }
- bool WriteUint64(uint64_t u64) {
- char buffer[20];
- char* end = internal::u64toa(u64, buffer);
- for (char* p = buffer; p != end; ++p)
- os_->Put(*p);
- return true;
- }
- bool WriteDouble(double d) {
- char buffer[25];
- char* end = internal::dtoa(d, buffer);
- for (char* p = buffer; p != end; ++p)
- os_->Put(*p);
- return true;
- }
- bool WriteString(const Ch* str, SizeType length) {
- static const char 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
- };
- os_->Put('\"');
- GenericStringStream<SourceEncoding> is(str);
- while (is.Tell() < length) {
- const Ch c = is.Peek();
- if (!TargetEncoding::supportUnicode && (unsigned)c >= 0x80) {
- // Unicode escaping
- unsigned codepoint;
- if (!SourceEncoding::Decode(is, &codepoint))
- return false;
- os_->Put('\\');
- os_->Put('u');
- if (codepoint <= 0xD7FF || (codepoint >= 0xE000 && codepoint <= 0xFFFF)) {
- os_->Put(hexDigits[(codepoint >> 12) & 15]);
- os_->Put(hexDigits[(codepoint >> 8) & 15]);
- os_->Put(hexDigits[(codepoint >> 4) & 15]);
- os_->Put(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;
- os_->Put(hexDigits[(lead >> 12) & 15]);
- os_->Put(hexDigits[(lead >> 8) & 15]);
- os_->Put(hexDigits[(lead >> 4) & 15]);
- os_->Put(hexDigits[(lead ) & 15]);
- os_->Put('\\');
- os_->Put('u');
- os_->Put(hexDigits[(trail >> 12) & 15]);
- os_->Put(hexDigits[(trail >> 8) & 15]);
- os_->Put(hexDigits[(trail >> 4) & 15]);
- os_->Put(hexDigits[(trail ) & 15]);
- }
- }
- else if ((sizeof(Ch) == 1 || (unsigned)c < 256) && escape[(unsigned char)c]) {
- is.Take();
- os_->Put('\\');
- os_->Put(escape[(unsigned char)c]);
- if (escape[(unsigned char)c] == 'u') {
- os_->Put('0');
- os_->Put('0');
- os_->Put(hexDigits[(unsigned char)c >> 4]);
- os_->Put(hexDigits[(unsigned char)c & 0xF]);
- }
- }
- else
- if (!Transcoder<SourceEncoding, TargetEncoding>::Transcode(is, *os_))
- return false;
- }
- os_->Put('\"');
- return true;
- }
- bool WriteStartObject() { os_->Put('{'); return true; }
- bool WriteEndObject() { os_->Put('}'); return true; }
- bool WriteStartArray() { os_->Put('['); return true; }
- bool WriteEndArray() { os_->Put(']'); return true; }
- void Prefix(Type type) {
- (void)type;
- if (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;
- }
- }
- OutputStream* os_;
- internal::Stack<StackAllocator> level_stack_;
- 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(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(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(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(20 - (end - buffer));
- return true;
- }
- template<>
- inline bool Writer<StringBuffer>::WriteDouble(double d) {
- char *buffer = os_->Push(25);
- char* end = internal::dtoa(d, buffer);
- os_->Pop(25 - (end - buffer));
- return true;
- }
- RAPIDJSON_NAMESPACE_END
- #ifdef _MSC_VER
- RAPIDJSON_DIAG_POP
- #endif
- #endif // RAPIDJSON_RAPIDJSON_H_
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