writer.h
// Copyright (C) 2011 Milo Yip
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#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
#ifdef _MSC_VER
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(4127) // conditional expression is constant
#endif
namespace rapidjson {
//! 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 allocator User supplied allocator. If it is null, it will create a private one.
\param levelDepth Initial capacity of stack.
*/
Writer(OutputStream& os, StackAllocator* stackAllocator = 0, size_t levelDepth = kDefaultLevelDepth) :
os_(&os), level_stack_(stackAllocator, levelDepth * sizeof(Level)), hasRoot_(false) {}
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);
}
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 if (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
return false; // invalid code point
}
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
Transcoder<SourceEncoding, TargetEncoding>::Transcode(is, *os_);
}
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;
}
} // namespace rapidjson
#ifdef _MSC_VER
RAPIDJSON_DIAG_POP
#endif
#endif // RAPIDJSON_RAPIDJSON_H_
rapidjson::kTrueType
true
Definition: rapidjson.h:570
rapidjson::Writer::Double
bool Double(double d)
Writes the given double value to the stream.
Definition: writer.h:120
rapidjson::SizeType
unsigned SizeType
Size type (for string lengths, array sizes, etc.)
Definition: rapidjson.h:247
rapidjson::kFalseType
false
Definition: rapidjson.h:569
rapidjson::Writer::Level::inArray
bool inArray
true if in array, otherwise in object
Definition: writer.h:179
rapidjson::Writer::Level
Information for each nested level.
Definition: writer.h:176
rapidjson::Writer::String
bool String(const Ch *str)
Simpler but slower overload.
Definition: writer.h:169
rapidjson::Type
Type
Type of JSON value.
Definition: rapidjson.h:567
rapidjson::kObjectType
object
Definition: rapidjson.h:571
rapidjson::Writer::Writer
Writer(OutputStream &os, StackAllocator *stackAllocator=0, size_t levelDepth=kDefaultLevelDepth)
Constructor.
Definition: writer.h:65
rapidjson::Writer::Level::valueCount
size_t valueCount
number of values in this level
Definition: writer.h:178
rapidjson::kArrayType
array
Definition: rapidjson.h:572
rapidjson::Writer
JSON writer.
Definition: writer.h:56
rapidjson
main RapidJSON namespace
Definition: rapidjson.h:241
rapidjson::Writer::IsComplete
bool IsComplete() const
Checks whether the output is a complete JSON.
Definition: writer.h:99
rapidjson::kNullType
null
Definition: rapidjson.h:568
rapidjson::kStringType
string
Definition: rapidjson.h:573
rapidjson.h
common definitions and configuration
rapidjson::Transcoder::Transcode
static RAPIDJSON_FORCEINLINE bool Transcode(InputStream &is, OutputStream &os)
Take one Unicode codepoint from source encoding, convert it to target encoding and put it to the outp...
Definition: encodings.h:594
rapidjson::Writer::Reset
void Reset(OutputStream &os)
Reset the writer with a new stream.
Definition: writer.h:89
RAPIDJSON_ASSERT
#define RAPIDJSON_ASSERT(x)
Assertion.
Definition: rapidjson.h:269
rapidjson::kNumberType
number
Definition: rapidjson.h:574