jsoncpp/include/json/value.h

936 lines
30 KiB
C++

// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
// Distributed under MIT license, or public domain if desired and
// recognized in your jurisdiction.
// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
#ifndef JSON_H_INCLUDED
#define JSON_H_INCLUDED
#if !defined(JSON_IS_AMALGAMATION)
#include "forwards.h"
#endif // if !defined(JSON_IS_AMALGAMATION)
// Conditional NORETURN attribute on the throw functions would:
// a) suppress false positives from static code analysis
// b) possibly improve optimization opportunities.
#if !defined(JSONCPP_NORETURN)
#if defined(_MSC_VER) && _MSC_VER == 1800
#define JSONCPP_NORETURN __declspec(noreturn)
#else
#define JSONCPP_NORETURN [[noreturn]]
#endif
#endif
// Support for '= delete' with template declarations was a late addition
// to the c++11 standard and is rejected by clang 3.8 and Apple clang 8.2
// even though these declare themselves to be c++11 compilers.
#if !defined(JSONCPP_TEMPLATE_DELETE)
#if defined(__clang__) && defined(__apple_build_version__)
#if __apple_build_version__ <= 8000042
#define JSONCPP_TEMPLATE_DELETE
#endif
#elif defined(__clang__)
#if __clang_major__ == 3 && __clang_minor__ <= 8
#define JSONCPP_TEMPLATE_DELETE
#endif
#endif
#if !defined(JSONCPP_TEMPLATE_DELETE)
#define JSONCPP_TEMPLATE_DELETE = delete
#endif
#endif
#include <array>
#include <exception>
#include <map>
#include <memory>
#include <string>
#include <vector>
// Disable warning C4251: <data member>: <type> needs to have dll-interface to
// be used by...
#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
#pragma warning(push)
#pragma warning(disable : 4251 4275)
#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
#pragma pack(push, 8)
/** \brief JSON (JavaScript Object Notation).
*/
namespace Json {
#if JSON_USE_EXCEPTION
/** Base class for all exceptions we throw.
*
* We use nothing but these internally. Of course, STL can throw others.
*/
class JSON_API Exception : public std::exception {
public:
Exception(String msg);
~Exception() noexcept override;
char const* what() const noexcept override;
protected:
String msg_;
};
/** Exceptions which the user cannot easily avoid.
*
* E.g. out-of-memory (when we use malloc), stack-overflow, malicious input
*
* \remark derived from Json::Exception
*/
class JSON_API RuntimeError : public Exception {
public:
RuntimeError(String const& msg);
};
/** Exceptions thrown by JSON_ASSERT/JSON_FAIL macros.
*
* These are precondition-violations (user bugs) and internal errors (our bugs).
*
* \remark derived from Json::Exception
*/
class JSON_API LogicError : public Exception {
public:
LogicError(String const& msg);
};
#endif
/// used internally
JSONCPP_NORETURN void throwRuntimeError(String const& msg);
/// used internally
JSONCPP_NORETURN void throwLogicError(String const& msg);
/** \brief Type of the value held by a Value object.
*/
enum ValueType {
nullValue = 0, ///< 'null' value
intValue, ///< signed integer value
uintValue, ///< unsigned integer value
realValue, ///< double value
stringValue, ///< UTF-8 string value
booleanValue, ///< bool value
arrayValue, ///< array value (ordered list)
objectValue ///< object value (collection of name/value pairs).
};
enum CommentPlacement {
commentBefore = 0, ///< a comment placed on the line before a value
commentAfterOnSameLine, ///< a comment just after a value on the same line
commentAfter, ///< a comment on the line after a value (only make sense for
/// root value)
numberOfCommentPlacement
};
/** \brief Type of precision for formatting of real values.
*/
enum PrecisionType {
significantDigits = 0, ///< we set max number of significant digits in string
decimalPlaces ///< we set max number of digits after "." in string
};
/** \brief Lightweight wrapper to tag static string.
*
* Value constructor and objectValue member assignment takes advantage of the
* StaticString and avoid the cost of string duplication when storing the
* string or the member name.
*
* Example of usage:
* \code
* Json::Value aValue( StaticString("some text") );
* Json::Value object;
* static const StaticString code("code");
* object[code] = 1234;
* \endcode
*/
class JSON_API StaticString {
public:
explicit StaticString(const char* czstring) : c_str_(czstring) {}
operator const char*() const { return c_str_; }
const char* c_str() const { return c_str_; }
private:
const char* c_str_;
};
/** \brief Represents a <a HREF="http://www.json.org">JSON</a> value.
*
* This class is a discriminated union wrapper that can represents a:
* - signed integer [range: Value::minInt - Value::maxInt]
* - unsigned integer (range: 0 - Value::maxUInt)
* - double
* - UTF-8 string
* - boolean
* - 'null'
* - an ordered list of Value
* - collection of name/value pairs (javascript object)
*
* The type of the held value is represented by a #ValueType and
* can be obtained using type().
*
* Values of an #objectValue or #arrayValue can be accessed using operator[]()
* methods.
* Non-const methods will automatically create the a #nullValue element
* if it does not exist.
* The sequence of an #arrayValue will be automatically resized and initialized
* with #nullValue. resize() can be used to enlarge or truncate an #arrayValue.
*
* The get() methods can be used to obtain default value in the case the
* required element does not exist.
*
* It is possible to iterate over the list of member keys of an object using
* the getMemberNames() method.
*
* \note #Value string-length fit in size_t, but keys must be < 2^30.
* (The reason is an implementation detail.) A #CharReader will raise an
* exception if a bound is exceeded to avoid security holes in your app,
* but the Value API does *not* check bounds. That is the responsibility
* of the caller.
*/
class JSON_API Value {
friend class ValueIteratorBase;
public:
using Members = std::vector<String>;
using iterator = ValueIterator;
using const_iterator = ValueConstIterator;
using UInt = Json::UInt;
using Int = Json::Int;
#if defined(JSON_HAS_INT64)
using UInt64 = Json::UInt64;
using Int64 = Json::Int64;
#endif // defined(JSON_HAS_INT64)
using LargestInt = Json::LargestInt;
using LargestUInt = Json::LargestUInt;
using ArrayIndex = Json::ArrayIndex;
// Required for boost integration, e. g. BOOST_TEST
using value_type = std::string;
#if JSON_USE_NULLREF
// Binary compatibility kludges, do not use.
static const Value& null;
static const Value& nullRef;
#endif
// null and nullRef are deprecated, use this instead.
static Value const& nullSingleton();
/// Minimum signed integer value that can be stored in a Json::Value.
static constexpr LargestInt minLargestInt =
LargestInt(~(LargestUInt(-1) / 2));
/// Maximum signed integer value that can be stored in a Json::Value.
static constexpr LargestInt maxLargestInt = LargestInt(LargestUInt(-1) / 2);
/// Maximum unsigned integer value that can be stored in a Json::Value.
static constexpr LargestUInt maxLargestUInt = LargestUInt(-1);
/// Minimum signed int value that can be stored in a Json::Value.
static constexpr Int minInt = Int(~(UInt(-1) / 2));
/// Maximum signed int value that can be stored in a Json::Value.
static constexpr Int maxInt = Int(UInt(-1) / 2);
/// Maximum unsigned int value that can be stored in a Json::Value.
static constexpr UInt maxUInt = UInt(-1);
#if defined(JSON_HAS_INT64)
/// Minimum signed 64 bits int value that can be stored in a Json::Value.
static constexpr Int64 minInt64 = Int64(~(UInt64(-1) / 2));
/// Maximum signed 64 bits int value that can be stored in a Json::Value.
static constexpr Int64 maxInt64 = Int64(UInt64(-1) / 2);
/// Maximum unsigned 64 bits int value that can be stored in a Json::Value.
static constexpr UInt64 maxUInt64 = UInt64(-1);
#endif // defined(JSON_HAS_INT64)
/// Default precision for real value for string representation.
static constexpr UInt defaultRealPrecision = 17;
// The constant is hard-coded because some compiler have trouble
// converting Value::maxUInt64 to a double correctly (AIX/xlC).
// Assumes that UInt64 is a 64 bits integer.
static constexpr double maxUInt64AsDouble = 18446744073709551615.0;
// Workaround for bug in the NVIDIAs CUDA 9.1 nvcc compiler
// when using gcc and clang backend compilers. CZString
// cannot be defined as private. See issue #486
#ifdef __NVCC__
public:
#else
private:
#endif
#ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
class CZString {
public:
enum DuplicationPolicy { noDuplication = 0, duplicate, duplicateOnCopy };
CZString(ArrayIndex index);
CZString(char const* str, unsigned length, DuplicationPolicy allocate);
CZString(CZString const& other);
CZString(CZString&& other) noexcept;
~CZString();
CZString& operator=(const CZString& other);
CZString& operator=(CZString&& other) noexcept;
bool operator<(CZString const& other) const;
bool operator==(CZString const& other) const;
ArrayIndex index() const;
// const char* c_str() const; ///< \deprecated
char const* data() const;
unsigned length() const;
bool isStaticString() const;
private:
void swap(CZString& other);
struct StringStorage {
unsigned policy_ : 2;
unsigned length_ : 30; // 1GB max
};
char const* cstr_; // actually, a prefixed string, unless policy is noDup
union {
ArrayIndex index_;
StringStorage storage_;
};
};
public:
typedef std::map<CZString, Value> ObjectValues;
#endif // ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
public:
/**
* \brief Create a default Value of the given type.
*
* This is a very useful constructor.
* To create an empty array, pass arrayValue.
* To create an empty object, pass objectValue.
* Another Value can then be set to this one by assignment.
* This is useful since clear() and resize() will not alter types.
*
* Examples:
* \code
* Json::Value null_value; // null
* Json::Value arr_value(Json::arrayValue); // []
* Json::Value obj_value(Json::objectValue); // {}
* \endcode
*/
Value(ValueType type = nullValue);
Value(Int value);
Value(UInt value);
#if defined(JSON_HAS_INT64)
Value(Int64 value);
Value(UInt64 value);
#endif // if defined(JSON_HAS_INT64)
Value(double value);
Value(const char* value); ///< Copy til first 0. (NULL causes to seg-fault.)
Value(const char* begin, const char* end); ///< Copy all, incl zeroes.
/**
* \brief Constructs a value from a static string.
*
* Like other value string constructor but do not duplicate the string for
* internal storage. The given string must remain alive after the call to
* this constructor.
*
* \note This works only for null-terminated strings. (We cannot change the
* size of this class, so we have nowhere to store the length, which might be
* computed later for various operations.)
*
* Example of usage:
* \code
* static StaticString foo("some text");
* Json::Value aValue(foo);
* \endcode
*/
Value(const StaticString& value);
Value(const String& value);
Value(bool value);
Value(std::nullptr_t ptr) = delete;
Value(const Value& other);
Value(Value&& other) noexcept;
~Value();
/// \note Overwrite existing comments. To preserve comments, use
/// #swapPayload().
Value& operator=(const Value& other);
Value& operator=(Value&& other) noexcept;
/// Swap everything.
void swap(Value& other);
/// Swap values but leave comments and source offsets in place.
void swapPayload(Value& other);
/// copy everything.
void copy(const Value& other);
/// copy values but leave comments and source offsets in place.
void copyPayload(const Value& other);
ValueType type() const;
/// Compare payload only, not comments etc.
bool operator<(const Value& other) const;
bool operator<=(const Value& other) const;
bool operator>=(const Value& other) const;
bool operator>(const Value& other) const;
bool operator==(const Value& other) const;
bool operator!=(const Value& other) const;
int compare(const Value& other) const;
const char* asCString() const; ///< Embedded zeroes could cause you trouble!
#if JSONCPP_USING_SECURE_MEMORY
unsigned getCStringLength() const; // Allows you to understand the length of
// the CString
#endif
String asString() const; ///< Embedded zeroes are possible.
/** Get raw char* of string-value.
* \return false if !string. (Seg-fault if str or end are NULL.)
*/
bool getString(char const** begin, char const** end) const;
Int asInt() const;
UInt asUInt() const;
#if defined(JSON_HAS_INT64)
Int64 asInt64() const;
UInt64 asUInt64() const;
#endif // if defined(JSON_HAS_INT64)
LargestInt asLargestInt() const;
LargestUInt asLargestUInt() const;
float asFloat() const;
double asDouble() const;
bool asBool() const;
bool isNull() const;
bool isBool() const;
bool isInt() const;
bool isInt64() const;
bool isUInt() const;
bool isUInt64() const;
bool isIntegral() const;
bool isDouble() const;
bool isNumeric() const;
bool isString() const;
bool isArray() const;
bool isObject() const;
/// The `as<T>` and `is<T>` member function templates and specializations.
template <typename T> T as() const JSONCPP_TEMPLATE_DELETE;
template <typename T> bool is() const JSONCPP_TEMPLATE_DELETE;
bool isConvertibleTo(ValueType other) const;
/// Number of values in array or object
ArrayIndex size() const;
/// \brief Return true if empty array, empty object, or null;
/// otherwise, false.
bool empty() const;
/// Return !isNull()
explicit operator bool() const;
/// Remove all object members and array elements.
/// \pre type() is arrayValue, objectValue, or nullValue
/// \post type() is unchanged
void clear();
/// Resize the array to newSize elements.
/// New elements are initialized to null.
/// May only be called on nullValue or arrayValue.
/// \pre type() is arrayValue or nullValue
/// \post type() is arrayValue
void resize(ArrayIndex newSize);
//@{
/// Access an array element (zero based index). If the array contains less
/// than index element, then null value are inserted in the array so that
/// its size is index+1.
/// (You may need to say 'value[0u]' to get your compiler to distinguish
/// this from the operator[] which takes a string.)
Value& operator[](ArrayIndex index);
Value& operator[](int index);
//@}
//@{
/// Access an array element (zero based index).
/// (You may need to say 'value[0u]' to get your compiler to distinguish
/// this from the operator[] which takes a string.)
const Value& operator[](ArrayIndex index) const;
const Value& operator[](int index) const;
//@}
/// If the array contains at least index+1 elements, returns the element
/// value, otherwise returns defaultValue.
Value get(ArrayIndex index, const Value& defaultValue) const;
/// Return true if index < size().
bool isValidIndex(ArrayIndex index) const;
/// \brief Append value to array at the end.
///
/// Equivalent to jsonvalue[jsonvalue.size()] = value;
Value& append(const Value& value);
Value& append(Value&& value);
/// \brief Insert value in array at specific index
bool insert(ArrayIndex index, const Value& newValue);
bool insert(ArrayIndex index, Value&& newValue);
/// Access an object value by name, create a null member if it does not exist.
/// \note Because of our implementation, keys are limited to 2^30 -1 chars.
/// Exceeding that will cause an exception.
Value& operator[](const char* key);
/// Access an object value by name, returns null if there is no member with
/// that name.
const Value& operator[](const char* key) const;
/// Access an object value by name, create a null member if it does not exist.
/// \param key may contain embedded nulls.
Value& operator[](const String& key);
/// Access an object value by name, returns null if there is no member with
/// that name.
/// \param key may contain embedded nulls.
const Value& operator[](const String& key) const;
/** \brief Access an object value by name, create a null member if it does not
* exist.
*
* If the object has no entry for that name, then the member name used to
* store the new entry is not duplicated.
* Example of use:
* \code
* Json::Value object;
* static const StaticString code("code");
* object[code] = 1234;
* \endcode
*/
Value& operator[](const StaticString& key);
/// Return the member named key if it exist, defaultValue otherwise.
/// \note deep copy
Value get(const char* key, const Value& defaultValue) const;
/// Return the member named key if it exist, defaultValue otherwise.
/// \note deep copy
/// \note key may contain embedded nulls.
Value get(const char* begin, const char* end,
const Value& defaultValue) const;
/// Return the member named key if it exist, defaultValue otherwise.
/// \note deep copy
/// \param key may contain embedded nulls.
Value get(const String& key, const Value& defaultValue) const;
/// Most general and efficient version of isMember()const, get()const,
/// and operator[]const
/// \note As stated elsewhere, behavior is undefined if (end-begin) >= 2^30
Value const* find(char const* begin, char const* end) const;
/// Most general and efficient version of object-mutators.
/// \note As stated elsewhere, behavior is undefined if (end-begin) >= 2^30
/// \return non-zero, but JSON_ASSERT if this is neither object nor nullValue.
Value* demand(char const* begin, char const* end);
/// \brief Remove and return the named member.
///
/// Do nothing if it did not exist.
/// \pre type() is objectValue or nullValue
/// \post type() is unchanged
void removeMember(const char* key);
/// Same as removeMember(const char*)
/// \param key may contain embedded nulls.
void removeMember(const String& key);
/// Same as removeMember(const char* begin, const char* end, Value* removed),
/// but 'key' is null-terminated.
bool removeMember(const char* key, Value* removed);
/** \brief Remove the named map member.
*
* Update 'removed' iff removed.
* \param key may contain embedded nulls.
* \return true iff removed (no exceptions)
*/
bool removeMember(String const& key, Value* removed);
/// Same as removeMember(String const& key, Value* removed)
bool removeMember(const char* begin, const char* end, Value* removed);
/** \brief Remove the indexed array element.
*
* O(n) expensive operations.
* Update 'removed' iff removed.
* \return true if removed (no exceptions)
*/
bool removeIndex(ArrayIndex index, Value* removed);
/// Return true if the object has a member named key.
/// \note 'key' must be null-terminated.
bool isMember(const char* key) const;
/// Return true if the object has a member named key.
/// \param key may contain embedded nulls.
bool isMember(const String& key) const;
/// Same as isMember(String const& key)const
bool isMember(const char* begin, const char* end) const;
/// \brief Return a list of the member names.
///
/// If null, return an empty list.
/// \pre type() is objectValue or nullValue
/// \post if type() was nullValue, it remains nullValue
Members getMemberNames() const;
/// \deprecated Always pass len.
JSONCPP_DEPRECATED("Use setComment(String const&) instead.")
void setComment(const char* comment, CommentPlacement placement) {
setComment(String(comment, strlen(comment)), placement);
}
/// Comments must be //... or /* ... */
void setComment(const char* comment, size_t len, CommentPlacement placement) {
setComment(String(comment, len), placement);
}
/// Comments must be //... or /* ... */
void setComment(String comment, CommentPlacement placement);
bool hasComment(CommentPlacement placement) const;
/// Include delimiters and embedded newlines.
String getComment(CommentPlacement placement) const;
String toStyledString() const;
const_iterator begin() const;
const_iterator end() const;
iterator begin();
iterator end();
// Accessors for the [start, limit) range of bytes within the JSON text from
// which this value was parsed, if any.
void setOffsetStart(ptrdiff_t start);
void setOffsetLimit(ptrdiff_t limit);
ptrdiff_t getOffsetStart() const;
ptrdiff_t getOffsetLimit() const;
private:
void setType(ValueType v) {
bits_.value_type_ = static_cast<unsigned char>(v);
}
bool isAllocated() const { return bits_.allocated_; }
void setIsAllocated(bool v) { bits_.allocated_ = v; }
void initBasic(ValueType type, bool allocated = false);
void dupPayload(const Value& other);
void releasePayload();
void dupMeta(const Value& other);
Value& resolveReference(const char* key);
Value& resolveReference(const char* key, const char* end);
// struct MemberNamesTransform
//{
// typedef const char *result_type;
// const char *operator()( const CZString &name ) const
// {
// return name.c_str();
// }
//};
union ValueHolder {
LargestInt int_;
LargestUInt uint_;
double real_;
bool bool_;
char* string_; // if allocated_, ptr to { unsigned, char[] }.
ObjectValues* map_;
} value_;
struct {
// Really a ValueType, but types should agree for bitfield packing.
unsigned int value_type_ : 8;
// Unless allocated_, string_ must be null-terminated.
unsigned int allocated_ : 1;
} bits_;
class Comments {
public:
Comments() = default;
Comments(const Comments& that);
Comments(Comments&& that) noexcept;
Comments& operator=(const Comments& that);
Comments& operator=(Comments&& that) noexcept;
bool has(CommentPlacement slot) const;
String get(CommentPlacement slot) const;
void set(CommentPlacement slot, String comment);
private:
using Array = std::array<String, numberOfCommentPlacement>;
std::unique_ptr<Array> ptr_;
};
Comments comments_;
// [start, limit) byte offsets in the source JSON text from which this Value
// was extracted.
ptrdiff_t start_;
ptrdiff_t limit_;
};
template <> inline bool Value::as<bool>() const { return asBool(); }
template <> inline bool Value::is<bool>() const { return isBool(); }
template <> inline Int Value::as<Int>() const { return asInt(); }
template <> inline bool Value::is<Int>() const { return isInt(); }
template <> inline UInt Value::as<UInt>() const { return asUInt(); }
template <> inline bool Value::is<UInt>() const { return isUInt(); }
#if defined(JSON_HAS_INT64)
template <> inline Int64 Value::as<Int64>() const { return asInt64(); }
template <> inline bool Value::is<Int64>() const { return isInt64(); }
template <> inline UInt64 Value::as<UInt64>() const { return asUInt64(); }
template <> inline bool Value::is<UInt64>() const { return isUInt64(); }
#endif
template <> inline double Value::as<double>() const { return asDouble(); }
template <> inline bool Value::is<double>() const { return isDouble(); }
template <> inline String Value::as<String>() const { return asString(); }
template <> inline bool Value::is<String>() const { return isString(); }
/// These `as` specializations are type conversions, and do not have a
/// corresponding `is`.
template <> inline float Value::as<float>() const { return asFloat(); }
template <> inline const char* Value::as<const char*>() const {
return asCString();
}
/** \brief Experimental and untested: represents an element of the "path" to
* access a node.
*/
class JSON_API PathArgument {
public:
friend class Path;
PathArgument();
PathArgument(ArrayIndex index);
PathArgument(const char* key);
PathArgument(String key);
private:
enum Kind { kindNone = 0, kindIndex, kindKey };
String key_;
ArrayIndex index_{};
Kind kind_{kindNone};
};
/** \brief Experimental and untested: represents a "path" to access a node.
*
* Syntax:
* - "." => root node
* - ".[n]" => elements at index 'n' of root node (an array value)
* - ".name" => member named 'name' of root node (an object value)
* - ".name1.name2.name3"
* - ".[0][1][2].name1[3]"
* - ".%" => member name is provided as parameter
* - ".[%]" => index is provided as parameter
*/
class JSON_API Path {
public:
Path(const String& path, const PathArgument& a1 = PathArgument(),
const PathArgument& a2 = PathArgument(),
const PathArgument& a3 = PathArgument(),
const PathArgument& a4 = PathArgument(),
const PathArgument& a5 = PathArgument());
const Value& resolve(const Value& root) const;
Value resolve(const Value& root, const Value& defaultValue) const;
/// Creates the "path" to access the specified node and returns a reference on
/// the node.
Value& make(Value& root) const;
private:
using InArgs = std::vector<const PathArgument*>;
using Args = std::vector<PathArgument>;
void makePath(const String& path, const InArgs& in);
void addPathInArg(const String& path, const InArgs& in,
InArgs::const_iterator& itInArg, PathArgument::Kind kind);
static void invalidPath(const String& path, int location);
Args args_;
};
/** \brief base class for Value iterators.
*
*/
class JSON_API ValueIteratorBase {
public:
using iterator_category = std::bidirectional_iterator_tag;
using size_t = unsigned int;
using difference_type = int;
using SelfType = ValueIteratorBase;
bool operator==(const SelfType& other) const { return isEqual(other); }
bool operator!=(const SelfType& other) const { return !isEqual(other); }
difference_type operator-(const SelfType& other) const {
return other.computeDistance(*this);
}
/// Return either the index or the member name of the referenced value as a
/// Value.
Value key() const;
/// Return the index of the referenced Value, or -1 if it is not an
/// arrayValue.
UInt index() const;
/// Return the member name of the referenced Value, or "" if it is not an
/// objectValue.
/// \note Avoid `c_str()` on result, as embedded zeroes are possible.
String name() const;
/// Return the member name of the referenced Value. "" if it is not an
/// objectValue.
/// \deprecated This cannot be used for UTF-8 strings, since there can be
/// embedded nulls.
JSONCPP_DEPRECATED("Use `key = name();` instead.")
char const* memberName() const;
/// Return the member name of the referenced Value, or NULL if it is not an
/// objectValue.
/// \note Better version than memberName(). Allows embedded nulls.
char const* memberName(char const** end) const;
protected:
/*! Internal utility functions to assist with implementing
* other iterator functions. The const and non-const versions
* of the "deref" protected methods expose the protected
* current_ member variable in a way that can often be
* optimized away by the compiler.
*/
const Value& deref() const;
Value& deref();
void increment();
void decrement();
difference_type computeDistance(const SelfType& other) const;
bool isEqual(const SelfType& other) const;
void copy(const SelfType& other);
private:
Value::ObjectValues::iterator current_;
// Indicates that iterator is for a null value.
bool isNull_{true};
public:
// For some reason, BORLAND needs these at the end, rather
// than earlier. No idea why.
ValueIteratorBase();
explicit ValueIteratorBase(const Value::ObjectValues::iterator& current);
};
/** \brief const iterator for object and array value.
*
*/
class JSON_API ValueConstIterator : public ValueIteratorBase {
friend class Value;
public:
using value_type = const Value;
// typedef unsigned int size_t;
// typedef int difference_type;
using reference = const Value&;
using pointer = const Value*;
using SelfType = ValueConstIterator;
ValueConstIterator();
ValueConstIterator(ValueIterator const& other);
private:
/*! \internal Use by Value to create an iterator.
*/
explicit ValueConstIterator(const Value::ObjectValues::iterator& current);
public:
SelfType& operator=(const ValueIteratorBase& other);
SelfType operator++(int) {
SelfType temp(*this);
++*this;
return temp;
}
SelfType operator--(int) {
SelfType temp(*this);
--*this;
return temp;
}
SelfType& operator--() {
decrement();
return *this;
}
SelfType& operator++() {
increment();
return *this;
}
reference operator*() const { return deref(); }
pointer operator->() const { return &deref(); }
};
/** \brief Iterator for object and array value.
*/
class JSON_API ValueIterator : public ValueIteratorBase {
friend class Value;
public:
using value_type = Value;
using size_t = unsigned int;
using difference_type = int;
using reference = Value&;
using pointer = Value*;
using SelfType = ValueIterator;
ValueIterator();
explicit ValueIterator(const ValueConstIterator& other);
ValueIterator(const ValueIterator& other);
private:
/*! \internal Use by Value to create an iterator.
*/
explicit ValueIterator(const Value::ObjectValues::iterator& current);
public:
SelfType& operator=(const SelfType& other);
SelfType operator++(int) {
SelfType temp(*this);
++*this;
return temp;
}
SelfType operator--(int) {
SelfType temp(*this);
--*this;
return temp;
}
SelfType& operator--() {
decrement();
return *this;
}
SelfType& operator++() {
increment();
return *this;
}
/*! The return value of non-const iterators can be
* changed, so the these functions are not const
* because the returned references/pointers can be used
* to change state of the base class.
*/
reference operator*() const { return const_cast<reference>(deref()); }
pointer operator->() const { return const_cast<pointer>(&deref()); }
};
inline void swap(Value& a, Value& b) { a.swap(b); }
} // namespace Json
#pragma pack(pop)
#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
#pragma warning(pop)
#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
#endif // JSON_H_INCLUDED