value.h

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// 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_VALUE_H_INCLUDED
#define JSON_VALUE_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

#ifndef JSONCPP_HAS_STRING_VIEW
#if __cplusplus >= 201703L
#define JSONCPP_HAS_STRING_VIEW 1
#endif
#endif

#include <array>
#include <exception>
#include <map>
#include <memory>
#include <string>
#include <vector>

// Forward declaration for testing.
struct ValueTest;

#ifdef JSONCPP_HAS_STRING_VIEW
#include <string_view>
#endif

// 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)
#pragma pack()

namespace Json {

#if JSON_USE_EXCEPTION

class JSON_API Exception : public std::exception {
public:
  Exception(String msg);
  ~Exception() noexcept override;
  char const* what() const noexcept override;

protected:
  String msg_;
};

class JSON_API RuntimeError : public Exception {
public:
  RuntimeError(String const& msg);
};

class JSON_API LogicError : public Exception {
public:
  LogicError(String const& msg);
};
#endif

JSONCPP_NORETURN void throwRuntimeError(String const& msg);
JSONCPP_NORETURN void throwLogicError(String const& msg);

enum ValueType {
  nullValue = 0, 
  intValue,      
  uintValue,     
  realValue,     
  stringValue,   
  booleanValue,  
  arrayValue,    
  objectValue    
};

enum CommentPlacement {
  commentBefore = 0,      
  commentAfterOnSameLine, 
  commentAfter, 
  numberOfCommentPlacement
};

enum PrecisionType {
  significantDigits = 0, 
  decimalPlaces          
};

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_;
};

class JSON_API Value {
  friend class ValueIteratorBase;
  friend struct ::ValueTest;

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();

  static constexpr LargestInt minLargestInt =
      LargestInt(~(LargestUInt(-1) / 2));
  static constexpr LargestInt maxLargestInt = LargestInt(LargestUInt(-1) / 2);
  static constexpr LargestUInt maxLargestUInt = LargestUInt(-1);

  static constexpr Int minInt = Int(~(UInt(-1) / 2));
  static constexpr Int maxInt = Int(UInt(-1) / 2);
  static constexpr UInt maxUInt = UInt(-1);

#if defined(JSON_HAS_INT64)
  static constexpr Int64 minInt64 = Int64(~(UInt64(-1) / 2));
  static constexpr Int64 maxInt64 = Int64(UInt64(-1) / 2);
  static constexpr UInt64 maxUInt64 = UInt64(-1);
#endif // defined(JSON_HAS_INT64)
  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 JSON_API 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:
  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); 
  Value(const char* begin, const char* end); 

  Value(const StaticString& value);
  Value(const String& value);
#ifdef JSONCPP_HAS_STRING_VIEW
  inline Value(std::string_view value)
      : Value(value.data(), value.data() + value.length()) {}
#endif
  Value(bool value);
  Value(std::nullptr_t ptr) = delete;
  Value(const Value& other);
  Value(Value&& other) noexcept;
  ~Value();

  Value& operator=(const Value& other);
  Value& operator=(Value&& other) noexcept;

  void swap(Value& other);
  void swapPayload(Value& other);

  void copy(const Value& other);
  void copyPayload(const Value& other);

  ValueType type() 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;
  bool operator!=(const Value& other) const;
  int compare(const Value& other) const;

  const char* asCString() const; 
#if JSONCPP_USE_SECURE_MEMORY
  unsigned getCStringLength() const; // Allows you to understand the length of
                                     // the CString
#endif
  String asString() const; 

  bool getString(char const** begin, char const** end) const;
#ifdef JSONCPP_HAS_STRING_VIEW

  inline bool getString(std::string_view* str) const {
    char const* begin;
    char const* end;
    if (!getString(&begin, &end))
      return false;
    *str = std::string_view(begin, static_cast<size_t>(end - begin));
    return true;
  }
#endif
  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;

  template <typename T> T as() const JSONCPP_TEMPLATE_DELETE;
  template <typename T> bool is() const JSONCPP_TEMPLATE_DELETE;

  bool isConvertibleTo(ValueType other) const;

  ArrayIndex size() const;

  bool empty() const;

  explicit operator bool() const;

  void clear();

  void resize(ArrayIndex newSize);

  Value& operator[](ArrayIndex index);
  Value& operator[](int index);

  const Value& operator[](ArrayIndex index) const;
  const Value& operator[](int index) const;

  Value get(ArrayIndex index, const Value& defaultValue) const;
  bool isValidIndex(ArrayIndex index) const;
  Value& append(const Value& value);
  Value& append(Value&& value);

  bool insert(ArrayIndex index, const Value& newValue);
  bool insert(ArrayIndex index, Value&& newValue);

#ifdef JSONCPP_HAS_STRING_VIEW
  inline Value& operator[](std::string_view key) {
    return resolveReference(key.data(), key.data() + key.length());
  }
  inline const Value& operator[](std::string_view key) const {
    Value const* found = find(key.data(), key.data() + key.length());
    if (!found)
      return nullSingleton();
    return *found;
  }
#endif
  Value& operator[](const char* key);
  const Value& operator[](const char* key) const;
  Value& operator[](const String& key);
  const Value& operator[](const String& key) const;
  Value& operator[](const StaticString& key);
#ifdef JSONCPP_HAS_STRING_VIEW
  inline Value get(std::string_view key, const Value& defaultValue) const {
    return get(key.data(), key.data() + key.length(), defaultValue);
  }
#endif
  Value get(const char* key, const Value& defaultValue) const;
  Value get(const String& key, const Value& defaultValue) const;
  Value get(const char* begin, const char* end,
            const Value& defaultValue) const;
  Value const* find(char const* begin, char const* end) const;
  Value const* find(const String& key) const;

  template <typename T, bool (T::*TMemFn)() const>
  Value const* findValue(const String& key) const {
    Value const* found = find(key);
    if (!found || !(found->*TMemFn)())
      return nullptr;
    return found;
  }

  Value const* findNull(const String& key) const;
  Value const* findBool(const String& key) const;
  Value const* findInt(const String& key) const;
  Value const* findInt64(const String& key) const;
  Value const* findUInt(const String& key) const;
  Value const* findUInt64(const String& key) const;
  Value const* findIntegral(const String& key) const;
  Value const* findDouble(const String& key) const;
  Value const* findNumeric(const String& key) const;
  Value const* findString(const String& key) const;
  Value const* findArray(const String& key) const;
  Value const* findObject(const String& key) const;

  Value* demand(char const* begin, char const* end);
#if JSONCPP_HAS_STRING_VIEW
  inline void removeMember(std::string_view key) {
    removeMember(key.data(), key.data() + key.length(), nullptr);
  }
#endif
  void removeMember(const char* key);
  void removeMember(const String& key);
#if JSONCPP_HAS_STRING_VIEW
  inline bool removeMember(std::string_view key, Value* removed) {
    return removeMember(key.data(), key.data() + key.length(), removed);
  }
#endif
  bool removeMember(String const& key, Value* removed);
  bool removeMember(const char* key, Value* removed);
  bool removeMember(const char* begin, const char* end, Value* removed);
  bool removeIndex(ArrayIndex index, Value* removed);

#ifdef JSONCPP_HAS_STRING_VIEW
  inline bool isMember(std::string_view key) const {
    return isMember(key.data(), key.data() + key.length());
  }
#endif
  bool isMember(const char* key) const;
  bool isMember(const String& key) const;
  bool isMember(const char* begin, const char* end) const;

  Members getMemberNames() const;

  JSONCPP_DEPRECATED("Use setComment(String const&) instead.")
  void setComment(const char* comment, CommentPlacement placement) {
    setComment(String(comment, strlen(comment)), placement);
  }
  void setComment(const char* comment, size_t len, CommentPlacement placement) {
    setComment(String(comment, len), placement);
  }
  void setComment(String comment, CommentPlacement placement);
  bool hasComment(CommentPlacement placement) const;
  String getComment(CommentPlacement placement) const;

  String toStyledString() const;

  const_iterator begin() const;
  const_iterator end() const;

  iterator begin();
  iterator end();

  // \brief Returns a view of member pairs for range-based for loops.
  ValueMembersView members();
  // \brief Returns a view of member pairs for range-based for loops.
  ValueConstMembersView members() const;

  const Value& front() const;

  Value& front();

  const Value& back() const;

  Value& back();

  // 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(); }

template <> inline float Value::as<float>() const { return asFloat(); }
template <> inline const char* Value::as<const char*>() const {
  return asCString();
}

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};
};

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;
  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_;
};

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);
  }

  Value key() const;

  UInt index() const;

  String name() const;

  JSONCPP_DEPRECATED("Use `key = name();` instead.")
  char const* memberName() const;
  char const* memberName(char const** end) const;

protected:
  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);
};

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:
  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(); }
};

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:
  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;
  }

  reference operator*() const { return const_cast<reference>(deref()); }
  pointer operator->() const { return const_cast<pointer>(&deref()); }
};

struct MemberProxy {
  const String name;
  Value& value;
};

struct ConstMemberProxy {
  const String name;
  const Value& value;
};

class ValueMembersIterator {
public:
  using iterator_category = std::forward_iterator_tag;
  using value_type = MemberProxy;
  using difference_type = int;
  using pointer = MemberProxy*;
  using reference = MemberProxy;

  ValueMembersIterator() = default;
  explicit ValueMembersIterator(ValueIterator const& iter) : it_(iter) {}

  ValueMembersIterator& operator++() {
    ++it_;
    return *this;
  }
  ValueMembersIterator operator++(int) {
    ValueMembersIterator temp(*this);
    ++*this;
    return temp;
  }
  bool operator==(ValueMembersIterator const& other) const {
    return it_ == other.it_;
  }
  bool operator!=(ValueMembersIterator const& other) const {
    return it_ != other.it_;
  }
  MemberProxy operator*() const { return MemberProxy{it_.name(), *it_}; }

private:
  ValueIterator it_;
};

class ValueConstMembersIterator {
public:
  using iterator_category = std::forward_iterator_tag;
  using value_type = ConstMemberProxy;
  using difference_type = int;
  using pointer = ConstMemberProxy*;
  using reference = ConstMemberProxy;

  ValueConstMembersIterator() = default;
  explicit ValueConstMembersIterator(ValueConstIterator const& iter)
      : it_(iter) {}

  ValueConstMembersIterator& operator++() {
    ++it_;
    return *this;
  }
  ValueConstMembersIterator operator++(int) {
    ValueConstMembersIterator temp(*this);
    ++*this;
    return temp;
  }
  bool operator==(ValueConstMembersIterator const& other) const {
    return it_ == other.it_;
  }
  bool operator!=(ValueConstMembersIterator const& other) const {
    return it_ != other.it_;
  }
  ConstMemberProxy operator*() const {
    return ConstMemberProxy{it_.name(), *it_};
  }

private:
  ValueConstIterator it_;
};

class ValueMembersView {
public:
  ValueMembersView(ValueIterator begin, ValueIterator end)
      : begin_(begin), end_(end) {}
  ValueMembersIterator begin() const { return ValueMembersIterator(begin_); }
  ValueMembersIterator end() const { return ValueMembersIterator(end_); }

private:
  ValueIterator begin_;
  ValueIterator end_;
};

class ValueConstMembersView {
public:
  ValueConstMembersView(ValueConstIterator begin, ValueConstIterator end)
      : begin_(begin), end_(end) {}
  ValueConstMembersIterator begin() const {
    return ValueConstMembersIterator(begin_);
  }
  ValueConstMembersIterator end() const {
    return ValueConstMembersIterator(end_);
  }

private:
  ValueConstIterator begin_;
  ValueConstIterator end_;
};

inline ValueMembersView Value::members() {
  return ValueMembersView(begin(), end());
}
inline ValueConstMembersView Value::members() const {
  return ValueConstMembersView(begin(), end());
}

inline void swap(Value& a, Value& b) { a.swap(b); }

inline const Value& Value::front() const { return *begin(); }

inline Value& Value::front() { return *begin(); }

inline const Value& Value::back() const { return *(--end()); }

inline Value& Value::back() { return *(--end()); }

} // 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