Merge branch 'upstream-jsoncpp' into update-jsoncpp

* upstream-jsoncpp:
  jsoncpp 2020-09-25 (9059f5ca)

1 files changed, 516 insertions, 544 deletions

diff --git a/Utilities/cmjsoncpp/src/lib_json/json_value.cpp b/Utilities/cmjsoncpp/src/lib_json/json_value.cpp
index f271e57..d59b7d9 100644
--- a/Utilities/cmjsoncpp/src/lib_json/json_value.cpp
+++ b/Utilities/cmjsoncpp/src/lib_json/json_value.cpp
@@ -8,20 +8,54 @@
 #include <json/value.h>
 #include <json/writer.h>
 #endif // if !defined(JSON_IS_AMALGAMATION)
-#include <math.h>
+#include <algorithm>
+#include <cassert>
+#include <cmath>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
 #include <sstream>
 #include <utility>
-#include <string.h>
-#include <assert.h>
-#ifdef JSON_USE_CPPTL
-#include <cpptl/conststring.h>
+
+// Provide implementation equivalent of std::snprintf for older _MSC compilers
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#include <stdarg.h>
+static int msvc_pre1900_c99_vsnprintf(char* outBuf, size_t size,
+                                      const char* format, va_list ap) {
+  int count = -1;
+  if (size != 0)
+    count = _vsnprintf_s(outBuf, size, _TRUNCATE, format, ap);
+  if (count == -1)
+    count = _vscprintf(format, ap);
+  return count;
+}
+
+int JSON_API msvc_pre1900_c99_snprintf(char* outBuf, size_t size,
+                                       const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  const int count = msvc_pre1900_c99_vsnprintf(outBuf, size, format, ap);
+  va_end(ap);
+  return count;
+}
+#endif
+
+// Disable warning C4702 : unreachable code
+#if defined(_MSC_VER)
+#pragma warning(disable : 4702)
 #endif
-#include <cstddef> // size_t
-#include <algorithm> // min()
 
 #define JSON_ASSERT_UNREACHABLE assert(false)
 
 namespace Json {
+template <typename T>
+static std::unique_ptr<T> cloneUnique(const std::unique_ptr<T>& p) {
+  std::unique_ptr<T> r;
+  if (p) {
+    r = std::unique_ptr<T>(new T(*p));
+  }
+  return r;
+}
 
 // This is a walkaround to avoid the static initialization of Value::null.
 // kNull must be word-aligned to avoid crashing on ARM.  We use an alignment of
@@ -31,50 +65,34 @@ namespace Json {
 #else
 #define ALIGNAS(byte_alignment)
 #endif
-//static const unsigned char ALIGNAS(8) kNull[sizeof(Value)] = { 0 };
-//const unsigned char& kNullRef = kNull[0];
-//const Value& Value::null = reinterpret_cast<const Value&>(kNullRef);
-//const Value& Value::nullRef = null;
 
 // static
-Value const& Value::nullSingleton()
-{
- static Value const nullStatic;
- return nullStatic;
+Value const& Value::nullSingleton() {
+  static Value const nullStatic;
+  return nullStatic;
 }
 
-// for backwards compatibility, we'll leave these global references around, but DO NOT
-// use them in JSONCPP library code any more!
+#if JSON_USE_NULLREF
+// for backwards compatibility, we'll leave these global references around, but
+// DO NOT use them in JSONCPP library code any more!
+// static
 Value const& Value::null = Value::nullSingleton();
-Value const& Value::nullRef = Value::nullSingleton();
 
-const Int Value::minInt = Int(~(UInt(-1) / 2));
-const Int Value::maxInt = Int(UInt(-1) / 2);
-const UInt Value::maxUInt = UInt(-1);
-#if defined(JSON_HAS_INT64)
-const Int64 Value::minInt64 = Int64(~(UInt64(-1) / 2));
-const Int64 Value::maxInt64 = Int64(UInt64(-1) / 2);
-const UInt64 Value::maxUInt64 = UInt64(-1);
-// 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 const double maxUInt64AsDouble = 18446744073709551615.0;
-#endif // defined(JSON_HAS_INT64)
-const LargestInt Value::minLargestInt = LargestInt(~(LargestUInt(-1) / 2));
-const LargestInt Value::maxLargestInt = LargestInt(LargestUInt(-1) / 2);
-const LargestUInt Value::maxLargestUInt = LargestUInt(-1);
+// static
+Value const& Value::nullRef = Value::nullSingleton();
+#endif
 
 #if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
 template <typename T, typename U>
 static inline bool InRange(double d, T min, U max) {
   // The casts can lose precision, but we are looking only for
   // an approximate range. Might fail on edge cases though. ~cdunn
-  //return d >= static_cast<double>(min) && d <= static_cast<double>(max);
-  return d >= min && d <= max;
+  return d >= static_cast<double>(min) && d <= static_cast<double>(max);
 }
 #else  // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
 static inline double integerToDouble(Json::UInt64 value) {
-  return static_cast<double>(Int64(value / 2)) * 2.0 + static_cast<double>(Int64(value & 1));
+  return static_cast<double>(Int64(value / 2)) * 2.0 +
+         static_cast<double>(Int64(value & 1));
 }
 
 template <typename T> static inline double integerToDouble(T value) {
@@ -94,19 +112,16 @@ static inline bool InRange(double d, T min, U max) {
  *               computed using strlen(value).
  * @return Pointer on the duplicate instance of string.
  */
-static inline char* duplicateStringValue(const char* value,
-                                         size_t length)
-{
+static inline char* duplicateStringValue(const char* value, size_t length) {
   // Avoid an integer overflow in the call to malloc below by limiting length
   // to a sane value.
   if (length >= static_cast<size_t>(Value::maxInt))
     length = Value::maxInt - 1;
 
-  char* newString = static_cast<char*>(malloc(length + 1));
-  if (newString == NULL) {
-    throwRuntimeError(
-        "in Json::Value::duplicateStringValue(): "
-        "Failed to allocate string value buffer");
+  auto newString = static_cast<char*>(malloc(length + 1));
+  if (newString == nullptr) {
+    throwRuntimeError("in Json::Value::duplicateStringValue(): "
+                      "Failed to allocate string value buffer");
   }
   memcpy(newString, value, length);
   newString[length] = 0;
@@ -115,31 +130,28 @@ static inline char* duplicateStringValue(const char* value,
 
 /* Record the length as a prefix.
  */
-static inline char* duplicateAndPrefixStringValue(
-    const char* value,
-    unsigned int length)
-{
+static inline char* duplicateAndPrefixStringValue(const char* value,
+                                                  unsigned int length) {
   // Avoid an integer overflow in the call to malloc below by limiting length
   // to a sane value.
-  JSON_ASSERT_MESSAGE(length <= static_cast<unsigned>(Value::maxInt) - sizeof(unsigned) - 1U,
+  JSON_ASSERT_MESSAGE(length <= static_cast<unsigned>(Value::maxInt) -
+                                    sizeof(unsigned) - 1U,
                       "in Json::Value::duplicateAndPrefixStringValue(): "
                       "length too big for prefixing");
-  unsigned actualLength = length + static_cast<unsigned>(sizeof(unsigned)) + 1U;
-  char* newString = static_cast<char*>(malloc(actualLength));
-  if (newString == 0) {
-    throwRuntimeError(
-        "in Json::Value::duplicateAndPrefixStringValue(): "
-        "Failed to allocate string value buffer");
+  size_t actualLength = sizeof(length) + length + 1;
+  auto newString = static_cast<char*>(malloc(actualLength));
+  if (newString == nullptr) {
+    throwRuntimeError("in Json::Value::duplicateAndPrefixStringValue(): "
+                      "Failed to allocate string value buffer");
   }
   *reinterpret_cast<unsigned*>(newString) = length;
   memcpy(newString + sizeof(unsigned), value, length);
-  newString[actualLength - 1U] = 0; // to avoid buffer over-run accidents by users later
+  newString[actualLength - 1U] =
+      0; // to avoid buffer over-run accidents by users later
   return newString;
 }
-inline static void decodePrefixedString(
-    bool isPrefixed, char const* prefixed,
-    unsigned* length, char const** value)
-{
+inline static void decodePrefixedString(bool isPrefixed, char const* prefixed,
+                                        unsigned* length, char const** value) {
   if (!isPrefixed) {
     *length = static_cast<unsigned>(strlen(prefixed));
     *value = prefixed;
@@ -148,7 +160,8 @@ inline static void decodePrefixedString(
     *value = prefixed + sizeof(unsigned);
   }
 }
-/** Free the string duplicated by duplicateStringValue()/duplicateAndPrefixStringValue().
+/** Free the string duplicated by
+ * duplicateStringValue()/duplicateAndPrefixStringValue().
  */
 #if JSONCPP_USING_SECURE_MEMORY
 static inline void releasePrefixedStringValue(char* value) {
@@ -161,17 +174,13 @@ static inline void releasePrefixedStringValue(char* value) {
 }
 static inline void releaseStringValue(char* value, unsigned length) {
   // length==0 => we allocated the strings memory
-  size_t size = (length==0) ? strlen(value) : length;
+  size_t size = (length == 0) ? strlen(value) : length;
   memset(value, 0, size);
   free(value);
 }
-#else // !JSONCPP_USING_SECURE_MEMORY
-static inline void releasePrefixedStringValue(char* value) {
-  free(value);
-}
-static inline void releaseStringValue(char* value, unsigned) {
-  free(value);
-}
+#else  // !JSONCPP_USING_SECURE_MEMORY
+static inline void releasePrefixedStringValue(char* value) { free(value); }
+static inline void releaseStringValue(char* value, unsigned) { free(value); }
 #endif // JSONCPP_USING_SECURE_MEMORY
 
 } // namespace Json
@@ -190,58 +199,28 @@ static inline void releaseStringValue(char* value, unsigned) {
 
 namespace Json {
 
-Exception::Exception(JSONCPP_STRING const& msg)
-  : msg_(msg)
-{}
-Exception::~Exception() JSONCPP_NOEXCEPT
-{}
-char const* Exception::what() const JSONCPP_NOEXCEPT
-{
-  return msg_.c_str();
-}
-RuntimeError::RuntimeError(JSONCPP_STRING const& msg)
-  : Exception(msg)
-{}
-LogicError::LogicError(JSONCPP_STRING const& msg)
-  : Exception(msg)
-{}
-JSONCPP_NORETURN void throwRuntimeError(JSONCPP_STRING const& msg)
-{
+#if JSON_USE_EXCEPTION
+Exception::Exception(String msg) : msg_(std::move(msg)) {}
+Exception::~Exception() noexcept = default;
+char const* Exception::what() const noexcept { return msg_.c_str(); }
+RuntimeError::RuntimeError(String const& msg) : Exception(msg) {}
+LogicError::LogicError(String const& msg) : Exception(msg) {}
+JSONCPP_NORETURN void throwRuntimeError(String const& msg) {
   throw RuntimeError(msg);
 }
-JSONCPP_NORETURN void throwLogicError(JSONCPP_STRING const& msg)
-{
+JSONCPP_NORETURN void throwLogicError(String const& msg) {
   throw LogicError(msg);
 }
-
-// //////////////////////////////////////////////////////////////////
-// //////////////////////////////////////////////////////////////////
-// //////////////////////////////////////////////////////////////////
-// class Value::CommentInfo
-// //////////////////////////////////////////////////////////////////
-// //////////////////////////////////////////////////////////////////
-// //////////////////////////////////////////////////////////////////
-
-Value::CommentInfo::CommentInfo() : comment_(0)
-{}
-
-Value::CommentInfo::~CommentInfo() {
-  if (comment_)
-    releaseStringValue(comment_, 0u);
+#else // !JSON_USE_EXCEPTION
+JSONCPP_NORETURN void throwRuntimeError(String const& msg) {
+  std::cerr << msg << std::endl;
+  abort();
 }
-
-void Value::CommentInfo::setComment(const char* text, size_t len) {
-  if (comment_) {
-    releaseStringValue(comment_, 0u);
-    comment_ = 0;
-  }
-  JSON_ASSERT(text != 0);
-  JSON_ASSERT_MESSAGE(
-      text[0] == '\0' || text[0] == '/',
-      "in Json::Value::setComment(): Comments must start with /");
-  // It seems that /**/ style comments are acceptable as well.
-  comment_ = duplicateStringValue(text, len);
+JSONCPP_NORETURN void throwLogicError(String const& msg) {
+  std::cerr << msg << std::endl;
+  abort();
 }
+#endif
 
 // //////////////////////////////////////////////////////////////////
 // //////////////////////////////////////////////////////////////////
@@ -254,36 +233,44 @@ void Value::CommentInfo::setComment(const char* text, size_t len) {
 // Notes: policy_ indicates if the string was allocated when
 // a string is stored.
 
-Value::CZString::CZString(ArrayIndex aindex) : cstr_(0), index_(aindex) {}
+Value::CZString::CZString(ArrayIndex index) : cstr_(nullptr), index_(index) {}
 
-Value::CZString::CZString(char const* str, unsigned ulength, DuplicationPolicy allocate)
+Value::CZString::CZString(char const* str, unsigned length,
+                          DuplicationPolicy allocate)
     : cstr_(str) {
   // allocate != duplicate
   storage_.policy_ = allocate & 0x3;
-  storage_.length_ = ulength & 0x3FFFFFFF;
+  storage_.length_ = length & 0x3FFFFFFF;
 }
 
 Value::CZString::CZString(const CZString& other) {
-  cstr_ = (other.storage_.policy_ != noDuplication && other.cstr_ != 0
-				 ? duplicateStringValue(other.cstr_, other.storage_.length_)
-				 : other.cstr_);
-  storage_.policy_ = static_cast<unsigned>(other.cstr_
-                 ? (static_cast<DuplicationPolicy>(other.storage_.policy_) == noDuplication
-                     ? noDuplication : duplicate)
-                 : static_cast<DuplicationPolicy>(other.storage_.policy_)) & 3U;
+  cstr_ = (other.storage_.policy_ != noDuplication && other.cstr_ != nullptr
+               ? duplicateStringValue(other.cstr_, other.storage_.length_)
+               : other.cstr_);
+  storage_.policy_ =
+      static_cast<unsigned>(
+          other.cstr_
+              ? (static_cast<DuplicationPolicy>(other.storage_.policy_) ==
+                         noDuplication
+                     ? noDuplication
+                     : duplicate)
+              : static_cast<DuplicationPolicy>(other.storage_.policy_)) &
+      3U;
   storage_.length_ = other.storage_.length_;
 }
 
-#if JSON_HAS_RVALUE_REFERENCES
 Value::CZString::CZString(CZString&& other)
-  : cstr_(other.cstr_), index_(other.index_) {
+    : cstr_(other.cstr_), index_(other.index_) {
   other.cstr_ = nullptr;
 }
-#endif
 
 Value::CZString::~CZString() {
   if (cstr_ && storage_.policy_ == duplicate) {
-	  releaseStringValue(const_cast<char*>(cstr_), storage_.length_ + 1u); //+1 for null terminating character for sake of completeness but not actually necessary
+    releaseStringValue(const_cast<char*>(cstr_),
+                       storage_.length_ + 1U); // +1 for null terminating
+                                               // character for sake of
+                                               // completeness but not actually
+                                               // necessary
   }
 }
 
@@ -298,36 +285,39 @@ Value::CZString& Value::CZString::operator=(const CZString& other) {
   return *this;
 }
 
-#if JSON_HAS_RVALUE_REFERENCES
 Value::CZString& Value::CZString::operator=(CZString&& other) {
   cstr_ = other.cstr_;
   index_ = other.index_;
   other.cstr_ = nullptr;
   return *this;
 }
-#endif
 
 bool Value::CZString::operator<(const CZString& other) const {
-  if (!cstr_) return index_ < other.index_;
-  //return strcmp(cstr_, other.cstr_) < 0;
+  if (!cstr_)
+    return index_ < other.index_;
+  // return strcmp(cstr_, other.cstr_) < 0;
   // Assume both are strings.
   unsigned this_len = this->storage_.length_;
   unsigned other_len = other.storage_.length_;
   unsigned min_len = std::min<unsigned>(this_len, other_len);
   JSON_ASSERT(this->cstr_ && other.cstr_);
   int comp = memcmp(this->cstr_, other.cstr_, min_len);
-  if (comp < 0) return true;
-  if (comp > 0) return false;
+  if (comp < 0)
+    return true;
+  if (comp > 0)
+    return false;
   return (this_len < other_len);
 }
 
 bool Value::CZString::operator==(const CZString& other) const {
-  if (!cstr_) return index_ == other.index_;
-  //return strcmp(cstr_, other.cstr_) == 0;
+  if (!cstr_)
+    return index_ == other.index_;
+  // return strcmp(cstr_, other.cstr_) == 0;
   // Assume both are strings.
   unsigned this_len = this->storage_.length_;
   unsigned other_len = other.storage_.length_;
-  if (this_len != other_len) return false;
+  if (this_len != other_len)
+    return false;
   JSON_ASSERT(this->cstr_ && other.cstr_);
   int comp = memcmp(this->cstr_, other.cstr_, this_len);
   return comp == 0;
@@ -335,10 +325,12 @@ bool Value::CZString::operator==(const CZString& other) const {
 
 ArrayIndex Value::CZString::index() const { return index_; }
 
-//const char* Value::CZString::c_str() const { return cstr_; }
+// const char* Value::CZString::c_str() const { return cstr_; }
 const char* Value::CZString::data() const { return cstr_; }
 unsigned Value::CZString::length() const { return storage_.length_; }
-bool Value::CZString::isStaticString() const { return storage_.policy_ == noDuplication; }
+bool Value::CZString::isStaticString() const {
+  return storage_.policy_ == noDuplication;
+}
 
 // //////////////////////////////////////////////////////////////////
 // //////////////////////////////////////////////////////////////////
@@ -352,10 +344,10 @@ bool Value::CZString::isStaticString() const { return storage_.policy_ == noDupl
  * memset( this, 0, sizeof(Value) )
  * This optimization is used in ValueInternalMap fast allocator.
  */
-Value::Value(ValueType vtype) {
+Value::Value(ValueType type) {
   static char const emptyString[] = "";
-  initBasic(vtype);
-  switch (vtype) {
+  initBasic(type);
+  switch (type) {
   case nullValue:
     break;
   case intValue:
@@ -408,20 +400,22 @@ Value::Value(double value) {
 
 Value::Value(const char* value) {
   initBasic(stringValue, true);
-  JSON_ASSERT_MESSAGE(value != NULL, "Null Value Passed to Value Constructor");
-  value_.string_ = duplicateAndPrefixStringValue(value, static_cast<unsigned>(strlen(value)));
+  JSON_ASSERT_MESSAGE(value != nullptr,
+                      "Null Value Passed to Value Constructor");
+  value_.string_ = duplicateAndPrefixStringValue(
+      value, static_cast<unsigned>(strlen(value)));
 }
 
-Value::Value(const char* beginValue, const char* endValue) {
+Value::Value(const char* begin, const char* end) {
   initBasic(stringValue, true);
   value_.string_ =
-      duplicateAndPrefixStringValue(beginValue, static_cast<unsigned>(endValue - beginValue));
+      duplicateAndPrefixStringValue(begin, static_cast<unsigned>(end - begin));
 }
 
-Value::Value(const JSONCPP_STRING& value) {
+Value::Value(const String& value) {
   initBasic(stringValue, true);
-  value_.string_ =
-      duplicateAndPrefixStringValue(value.data(), static_cast<unsigned>(value.length()));
+  value_.string_ = duplicateAndPrefixStringValue(
+      value.data(), static_cast<unsigned>(value.length()));
 }
 
 Value::Value(const StaticString& value) {
@@ -429,114 +423,44 @@ Value::Value(const StaticString& value) {
   value_.string_ = const_cast<char*>(value.c_str());
 }
 
-#ifdef JSON_USE_CPPTL
-Value::Value(const CppTL::ConstString& value) {
-  initBasic(stringValue, true);
-  value_.string_ = duplicateAndPrefixStringValue(value, static_cast<unsigned>(value.length()));
-}
-#endif
-
 Value::Value(bool value) {
   initBasic(booleanValue);
   value_.bool_ = value;
 }
 
-Value::Value(Value const& other)
-    : type_(other.type_), allocated_(false)
-      ,
-      comments_(0), start_(other.start_), limit_(other.limit_)
-{
-  switch (type_) {
-  case nullValue:
-  case intValue:
-  case uintValue:
-  case realValue:
-  case booleanValue:
-    value_ = other.value_;
-    break;
-  case stringValue:
-    if (other.value_.string_ && other.allocated_) {
-      unsigned len;
-      char const* str;
-      decodePrefixedString(other.allocated_, other.value_.string_,
-          &len, &str);
-      value_.string_ = duplicateAndPrefixStringValue(str, len);
-      allocated_ = true;
-    } else {
-      value_.string_ = other.value_.string_;
-      allocated_ = false;
-    }
-    break;
-  case arrayValue:
-  case objectValue:
-    value_.map_ = new ObjectValues(*other.value_.map_);
-    break;
-  default:
-    JSON_ASSERT_UNREACHABLE;
-  }
-  if (other.comments_) {
-    comments_ = new CommentInfo[numberOfCommentPlacement];
-    for (int comment = 0; comment < numberOfCommentPlacement; ++comment) {
-      const CommentInfo& otherComment = other.comments_[comment];
-      if (otherComment.comment_)
-        comments_[comment].setComment(
-            otherComment.comment_, strlen(otherComment.comment_));
-    }
-  }
+Value::Value(const Value& other) {
+  dupPayload(other);
+  dupMeta(other);
 }
 
-#if JSON_HAS_RVALUE_REFERENCES
-// Move constructor
 Value::Value(Value&& other) {
   initBasic(nullValue);
   swap(other);
 }
-#endif
 
 Value::~Value() {
-  switch (type_) {
-  case nullValue:
-  case intValue:
-  case uintValue:
-  case realValue:
-  case booleanValue:
-    break;
-  case stringValue:
-    if (allocated_)
-      releasePrefixedStringValue(value_.string_);
-    break;
-  case arrayValue:
-  case objectValue:
-    delete value_.map_;
-    break;
-  default:
-    JSON_ASSERT_UNREACHABLE;
-  }
-
-  delete[] comments_;
-
+  releasePayload();
   value_.uint_ = 0;
 }
 
-Value& Value::operator=(Value other) {
-  swap(other);
+Value& Value::operator=(const Value& other) {
+  Value(other).swap(*this);
+  return *this;
+}
+
+Value& Value::operator=(Value&& other) {
+  other.swap(*this);
   return *this;
 }
 
 void Value::swapPayload(Value& other) {
-  ValueType temp = type_;
-  type_ = other.type_;
-  other.type_ = temp;
+  std::swap(bits_, other.bits_);
   std::swap(value_, other.value_);
-  int temp2 = allocated_;
-  allocated_ = other.allocated_;
-  other.allocated_ = temp2 & 0x1;
 }
 
 void Value::copyPayload(const Value& other) {
-  type_ = other.type_;
-  value_ = other.value_;
-  allocated_ = other.allocated_;
+  releasePayload();
+  dupPayload(other);
 }
 
 void Value::swap(Value& other) {
@@ -548,12 +472,12 @@ void Value::swap(Value& other) {
 
 void Value::copy(const Value& other) {
   copyPayload(other);
-  comments_ = other.comments_;
-  start_ = other.start_;
-  limit_ = other.limit_;
+  dupMeta(other);
 }
 
-ValueType Value::type() const { return type_; }
+ValueType Value::type() const {
+  return static_cast<ValueType>(bits_.value_type_);
+}
 
 int Value::compare(const Value& other) const {
   if (*this < other)
@@ -564,10 +488,10 @@ int Value::compare(const Value& other) const {
 }
 
 bool Value::operator<(const Value& other) const {
-  int typeDelta = type_ - other.type_;
+  int typeDelta = type() - other.type();
   if (typeDelta)
-    return typeDelta < 0 ? true : false;
-  switch (type_) {
+    return typeDelta < 0;
+  switch (type()) {
   case nullValue:
     return false;
   case intValue:
@@ -578,30 +502,33 @@ bool Value::operator<(const Value& other) const {
     return value_.real_ < other.value_.real_;
   case booleanValue:
     return value_.bool_ < other.value_.bool_;
-  case stringValue:
-  {
-    if ((value_.string_ == 0) || (other.value_.string_ == 0)) {
-      if (other.value_.string_) return true;
-      else return false;
+  case stringValue: {
+    if ((value_.string_ == nullptr) || (other.value_.string_ == nullptr)) {
+      return other.value_.string_ != nullptr;
     }
     unsigned this_len;
     unsigned other_len;
     char const* this_str;
     char const* other_str;
-    decodePrefixedString(this->allocated_, this->value_.string_, &this_len, &this_str);
-    decodePrefixedString(other.allocated_, other.value_.string_, &other_len, &other_str);
+    decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                         &this_str);
+    decodePrefixedString(other.isAllocated(), other.value_.string_, &other_len,
+                         &other_str);
     unsigned min_len = std::min<unsigned>(this_len, other_len);
     JSON_ASSERT(this_str && other_str);
     int comp = memcmp(this_str, other_str, min_len);
-    if (comp < 0) return true;
-    if (comp > 0) return false;
+    if (comp < 0)
+      return true;
+    if (comp > 0)
+      return false;
     return (this_len < other_len);
   }
   case arrayValue:
   case objectValue: {
-    int delta = int(value_.map_->size() - other.value_.map_->size());
-    if (delta)
-      return delta < 0;
+    auto thisSize = value_.map_->size();
+    auto otherSize = other.value_.map_->size();
+    if (thisSize != otherSize)
+      return thisSize < otherSize;
     return (*value_.map_) < (*other.value_.map_);
   }
   default:
@@ -617,14 +544,9 @@ bool Value::operator>=(const Value& other) const { return !(*this < other); }
 bool Value::operator>(const Value& other) const { return other < *this; }
 
 bool Value::operator==(const Value& other) const {
-  // if ( type_ != other.type_ )
-  // GCC 2.95.3 says:
-  // attempt to take address of bit-field structure member `Json::Value::type_'
-  // Beats me, but a temp solves the problem.
-  int temp = other.type_;
-  if (type_ != temp)
+  if (type() != other.type())
     return false;
-  switch (type_) {
+  switch (type()) {
   case nullValue:
     return true;
   case intValue:
@@ -635,18 +557,20 @@ bool Value::operator==(const Value& other) const {
     return value_.real_ == other.value_.real_;
   case booleanValue:
     return value_.bool_ == other.value_.bool_;
-  case stringValue:
-  {
-    if ((value_.string_ == 0) || (other.value_.string_ == 0)) {
+  case stringValue: {
+    if ((value_.string_ == nullptr) || (other.value_.string_ == nullptr)) {
       return (value_.string_ == other.value_.string_);
     }
     unsigned this_len;
     unsigned other_len;
     char const* this_str;
     char const* other_str;
-    decodePrefixedString(this->allocated_, this->value_.string_, &this_len, &this_str);
-    decodePrefixedString(other.allocated_, other.value_.string_, &other_len, &other_str);
-    if (this_len != other_len) return false;
+    decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                         &this_str);
+    decodePrefixedString(other.isAllocated(), other.value_.string_, &other_len,
+                         &other_str);
+    if (this_len != other_len)
+      return false;
     JSON_ASSERT(this_str && other_str);
     int comp = memcmp(this_str, other_str, this_len);
     return comp == 0;
@@ -664,47 +588,55 @@ bool Value::operator==(const Value& other) const {
 bool Value::operator!=(const Value& other) const { return !(*this == other); }
 
 const char* Value::asCString() const {
-  JSON_ASSERT_MESSAGE(type_ == stringValue,
+  JSON_ASSERT_MESSAGE(type() == stringValue,
                       "in Json::Value::asCString(): requires stringValue");
-  if (value_.string_ == 0) return 0;
+  if (value_.string_ == nullptr)
+    return nullptr;
   unsigned this_len;
   char const* this_str;
-  decodePrefixedString(this->allocated_, this->value_.string_, &this_len, &this_str);
+  decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                       &this_str);
   return this_str;
 }
 
 #if JSONCPP_USING_SECURE_MEMORY
 unsigned Value::getCStringLength() const {
-  JSON_ASSERT_MESSAGE(type_ == stringValue,
-	                  "in Json::Value::asCString(): requires stringValue");
-  if (value_.string_ == 0) return 0;
+  JSON_ASSERT_MESSAGE(type() == stringValue,
+                      "in Json::Value::asCString(): requires stringValue");
+  if (value_.string_ == 0)
+    return 0;
   unsigned this_len;
   char const* this_str;
-  decodePrefixedString(this->allocated_, this->value_.string_, &this_len, &this_str);
+  decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                       &this_str);
   return this_len;
 }
 #endif
 
-bool Value::getString(char const** str, char const** cend) const {
-  if (type_ != stringValue) return false;
-  if (value_.string_ == 0) return false;
+bool Value::getString(char const** begin, char const** end) const {
+  if (type() != stringValue)
+    return false;
+  if (value_.string_ == nullptr)
+    return false;
   unsigned length;
-  decodePrefixedString(this->allocated_, this->value_.string_, &length, str);
-  *cend = *str + length;
+  decodePrefixedString(this->isAllocated(), this->value_.string_, &length,
+                       begin);
+  *end = *begin + length;
   return true;
 }
 
-JSONCPP_STRING Value::asString() const {
-  switch (type_) {
+String Value::asString() const {
+  switch (type()) {
   case nullValue:
     return "";
-  case stringValue:
-  {
-    if (value_.string_ == 0) return "";
+  case stringValue: {
+    if (value_.string_ == nullptr)
+      return "";
     unsigned this_len;
     char const* this_str;
-    decodePrefixedString(this->allocated_, this->value_.string_, &this_len, &this_str);
-    return JSONCPP_STRING(this_str, this_len);
+    decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                         &this_str);
+    return String(this_str, this_len);
   }
   case booleanValue:
     return value_.bool_ ? "true" : "false";
@@ -719,18 +651,8 @@ JSONCPP_STRING Value::asString() const {
   }
 }
 
-#ifdef JSON_USE_CPPTL
-CppTL::ConstString Value::asConstString() const {
-  unsigned len;
-  char const* str;
-  decodePrefixedString(allocated_, value_.string_,
-      &len, &str);
-  return CppTL::ConstString(str, len);
-}
-#endif
-
 Value::Int Value::asInt() const {
-  switch (type_) {
+  switch (type()) {
   case intValue:
     JSON_ASSERT_MESSAGE(isInt(), "LargestInt out of Int range");
     return Int(value_.int_);
@@ -752,7 +674,7 @@ Value::Int Value::asInt() const {
 }
 
 Value::UInt Value::asUInt() const {
-  switch (type_) {
+  switch (type()) {
   case intValue:
     JSON_ASSERT_MESSAGE(isUInt(), "LargestInt out of UInt range");
     return UInt(value_.int_);
@@ -776,7 +698,7 @@ Value::UInt Value::asUInt() const {
 #if defined(JSON_HAS_INT64)
 
 Value::Int64 Value::asInt64() const {
-  switch (type_) {
+  switch (type()) {
   case intValue:
     return Int64(value_.int_);
   case uintValue:
@@ -797,7 +719,7 @@ Value::Int64 Value::asInt64() const {
 }
 
 Value::UInt64 Value::asUInt64() const {
-  switch (type_) {
+  switch (type()) {
   case intValue:
     JSON_ASSERT_MESSAGE(isUInt64(), "LargestInt out of UInt64 range");
     return UInt64(value_.int_);
@@ -835,7 +757,7 @@ LargestUInt Value::asLargestUInt() const {
 }
 
 double Value::asDouble() const {
-  switch (type_) {
+  switch (type()) {
   case intValue:
     return static_cast<double>(value_.int_);
   case uintValue:
@@ -857,7 +779,7 @@ double Value::asDouble() const {
 }
 
 float Value::asFloat() const {
-  switch (type_) {
+  switch (type()) {
   case intValue:
     return static_cast<float>(value_.int_);
   case uintValue:
@@ -872,7 +794,7 @@ float Value::asFloat() const {
   case nullValue:
     return 0.0;
   case booleanValue:
-    return value_.bool_ ? 1.0f : 0.0f;
+    return value_.bool_ ? 1.0F : 0.0F;
   default:
     break;
   }
@@ -880,18 +802,20 @@ float Value::asFloat() const {
 }
 
 bool Value::asBool() const {
-  switch (type_) {
+  switch (type()) {
   case booleanValue:
     return value_.bool_;
   case nullValue:
     return false;
   case intValue:
-    return value_.int_ ? true : false;
+    return value_.int_ != 0;
   case uintValue:
-    return value_.uint_ ? true : false;
-  case realValue:
-    // This is kind of strange. Not recommended.
-    return (value_.real_ != 0.0) ? true : false;
+    return value_.uint_ != 0;
+  case realValue: {
+    // According to JavaScript language zero or NaN is regarded as false
+    const auto value_classification = std::fpclassify(value_.real_);
+    return value_classification != FP_ZERO && value_classification != FP_NAN;
+  }
   default:
     break;
   }
@@ -902,30 +826,30 @@ bool Value::isConvertibleTo(ValueType other) const {
   switch (other) {
   case nullValue:
     return (isNumeric() && asDouble() == 0.0) ||
-           (type_ == booleanValue && value_.bool_ == false) ||
-           (type_ == stringValue && asString().empty()) ||
-           (type_ == arrayValue && value_.map_->size() == 0) ||
-           (type_ == objectValue && value_.map_->size() == 0) ||
-           type_ == nullValue;
+           (type() == booleanValue && !value_.bool_) ||
+           (type() == stringValue && asString().empty()) ||
+           (type() == arrayValue && value_.map_->empty()) ||
+           (type() == objectValue && value_.map_->empty()) ||
+           type() == nullValue;
   case intValue:
     return isInt() ||
-           (type_ == realValue && InRange(value_.real_, minInt, maxInt)) ||
-           type_ == booleanValue || type_ == nullValue;
+           (type() == realValue && InRange(value_.real_, minInt, maxInt)) ||
+           type() == booleanValue || type() == nullValue;
   case uintValue:
     return isUInt() ||
-           (type_ == realValue && InRange(value_.real_, 0, maxUInt)) ||
-           type_ == booleanValue || type_ == nullValue;
+           (type() == realValue && InRange(value_.real_, 0, maxUInt)) ||
+           type() == booleanValue || type() == nullValue;
   case realValue:
-    return isNumeric() || type_ == booleanValue || type_ == nullValue;
+    return isNumeric() || type() == booleanValue || type() == nullValue;
   case booleanValue:
-    return isNumeric() || type_ == booleanValue || type_ == nullValue;
+    return isNumeric() || type() == booleanValue || type() == nullValue;
   case stringValue:
-    return isNumeric() || type_ == booleanValue || type_ == stringValue ||
-           type_ == nullValue;
+    return isNumeric() || type() == booleanValue || type() == stringValue ||
+           type() == nullValue;
   case arrayValue:
-    return type_ == arrayValue || type_ == nullValue;
+    return type() == arrayValue || type() == nullValue;
   case objectValue:
-    return type_ == objectValue || type_ == nullValue;
+    return type() == objectValue || type() == nullValue;
   }
   JSON_ASSERT_UNREACHABLE;
   return false;
@@ -933,7 +857,7 @@ bool Value::isConvertibleTo(ValueType other) const {
 
 /// Number of values in array or object
 ArrayIndex Value::size() const {
-  switch (type_) {
+  switch (type()) {
   case nullValue:
   case intValue:
   case uintValue:
@@ -957,20 +881,19 @@ ArrayIndex Value::size() const {
 
 bool Value::empty() const {
   if (isNull() || isArray() || isObject())
-    return size() == 0u;
-  else
-    return false;
+    return size() == 0U;
+  return false;
 }
 
-bool Value::operator!() const { return isNull(); }
+Value::operator bool() const { return !isNull(); }
 
 void Value::clear() {
-  JSON_ASSERT_MESSAGE(type_ == nullValue || type_ == arrayValue ||
-                          type_ == objectValue,
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == arrayValue ||
+                          type() == objectValue,
                       "in Json::Value::clear(): requires complex value");
   start_ = 0;
   limit_ = 0;
-  switch (type_) {
+  switch (type()) {
   case arrayValue:
   case objectValue:
     value_.map_->clear();
@@ -981,15 +904,15 @@ void Value::clear() {
 }
 
 void Value::resize(ArrayIndex newSize) {
-  JSON_ASSERT_MESSAGE(type_ == nullValue || type_ == arrayValue,
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == arrayValue,
                       "in Json::Value::resize(): requires arrayValue");
-  if (type_ == nullValue)
+  if (type() == nullValue)
     *this = Value(arrayValue);
   ArrayIndex oldSize = size();
   if (newSize == 0)
     clear();
   else if (newSize > oldSize)
-    (*this)[newSize - 1];
+    this->operator[](newSize - 1);
   else {
     for (ArrayIndex index = newSize; index < oldSize; ++index) {
       value_.map_->erase(index);
@@ -1000,12 +923,12 @@ void Value::resize(ArrayIndex newSize) {
 
 Value& Value::operator[](ArrayIndex index) {
   JSON_ASSERT_MESSAGE(
-      type_ == nullValue || type_ == arrayValue,
+      type() == nullValue || type() == arrayValue,
       "in Json::Value::operator[](ArrayIndex): requires arrayValue");
-  if (type_ == nullValue)
+  if (type() == nullValue)
     *this = Value(arrayValue);
   CZString key(index);
-  ObjectValues::iterator it = value_.map_->lower_bound(key);
+  auto it = value_.map_->lower_bound(key);
   if (it != value_.map_->end() && (*it).first == key)
     return (*it).second;
 
@@ -1023,9 +946,9 @@ Value& Value::operator[](int index) {
 
 const Value& Value::operator[](ArrayIndex index) const {
   JSON_ASSERT_MESSAGE(
-      type_ == nullValue || type_ == arrayValue,
+      type() == nullValue || type() == arrayValue,
       "in Json::Value::operator[](ArrayIndex)const: requires arrayValue");
-  if (type_ == nullValue)
+  if (type() == nullValue)
     return nullSingleton();
   CZString key(index);
   ObjectValues::const_iterator it = value_.map_->find(key);
@@ -1041,26 +964,85 @@ const Value& Value::operator[](int index) const {
   return (*this)[ArrayIndex(index)];
 }
 
-void Value::initBasic(ValueType vtype, bool allocated) {
-  type_ = vtype;
-  allocated_ = allocated;
-  comments_ = 0;
+void Value::initBasic(ValueType type, bool allocated) {
+  setType(type);
+  setIsAllocated(allocated);
+  comments_ = Comments{};
   start_ = 0;
   limit_ = 0;
 }
 
+void Value::dupPayload(const Value& other) {
+  setType(other.type());
+  setIsAllocated(false);
+  switch (type()) {
+  case nullValue:
+  case intValue:
+  case uintValue:
+  case realValue:
+  case booleanValue:
+    value_ = other.value_;
+    break;
+  case stringValue:
+    if (other.value_.string_ && other.isAllocated()) {
+      unsigned len;
+      char const* str;
+      decodePrefixedString(other.isAllocated(), other.value_.string_, &len,
+                           &str);
+      value_.string_ = duplicateAndPrefixStringValue(str, len);
+      setIsAllocated(true);
+    } else {
+      value_.string_ = other.value_.string_;
+    }
+    break;
+  case arrayValue:
+  case objectValue:
+    value_.map_ = new ObjectValues(*other.value_.map_);
+    break;
+  default:
+    JSON_ASSERT_UNREACHABLE;
+  }
+}
+
+void Value::releasePayload() {
+  switch (type()) {
+  case nullValue:
+  case intValue:
+  case uintValue:
+  case realValue:
+  case booleanValue:
+    break;
+  case stringValue:
+    if (isAllocated())
+      releasePrefixedStringValue(value_.string_);
+    break;
+  case arrayValue:
+  case objectValue:
+    delete value_.map_;
+    break;
+  default:
+    JSON_ASSERT_UNREACHABLE;
+  }
+}
+
+void Value::dupMeta(const Value& other) {
+  comments_ = other.comments_;
+  start_ = other.start_;
+  limit_ = other.limit_;
+}
+
 // Access an object value by name, create a null member if it does not exist.
 // @pre Type of '*this' is object or null.
 // @param key is null-terminated.
 Value& Value::resolveReference(const char* key) {
   JSON_ASSERT_MESSAGE(
-      type_ == nullValue || type_ == objectValue,
+      type() == nullValue || type() == objectValue,
       "in Json::Value::resolveReference(): requires objectValue");
-  if (type_ == nullValue)
+  if (type() == nullValue)
     *this = Value(objectValue);
-  CZString actualKey(
-      key, static_cast<unsigned>(strlen(key)), CZString::noDuplication); // NOTE!
-  ObjectValues::iterator it = value_.map_->lower_bound(actualKey);
+  CZString actualKey(key, static_cast<unsigned>(strlen(key)),
+                     CZString::noDuplication); // NOTE!
+  auto it = value_.map_->lower_bound(actualKey);
   if (it != value_.map_->end() && (*it).first == actualKey)
     return (*it).second;
 
@@ -1071,16 +1053,15 @@ Value& Value::resolveReference(const char* key) {
 }
 
 // @param key is not null-terminated.
-Value& Value::resolveReference(char const* key, char const* cend)
-{
+Value& Value::resolveReference(char const* key, char const* end) {
   JSON_ASSERT_MESSAGE(
-      type_ == nullValue || type_ == objectValue,
+      type() == nullValue || type() == objectValue,
       "in Json::Value::resolveReference(key, end): requires objectValue");
-  if (type_ == nullValue)
+  if (type() == nullValue)
     *this = Value(objectValue);
-  CZString actualKey(
-      key, static_cast<unsigned>(cend-key), CZString::duplicateOnCopy);
-  ObjectValues::iterator it = value_.map_->lower_bound(actualKey);
+  CZString actualKey(key, static_cast<unsigned>(end - key),
+                     CZString::duplicateOnCopy);
+  auto it = value_.map_->lower_bound(actualKey);
   if (it != value_.map_->end() && (*it).first == actualKey)
     return (*it).second;
 
@@ -1097,27 +1078,35 @@ Value Value::get(ArrayIndex index, const Value& defaultValue) const {
 
 bool Value::isValidIndex(ArrayIndex index) const { return index < size(); }
 
-Value const* Value::find(char const* key, char const* cend) const
-{
-  JSON_ASSERT_MESSAGE(
-      type_ == nullValue || type_ == objectValue,
-      "in Json::Value::find(key, end, found): requires objectValue or nullValue");
-  if (type_ == nullValue) return NULL;
-  CZString actualKey(key, static_cast<unsigned>(cend-key), CZString::noDuplication);
+Value const* Value::find(char const* begin, char const* end) const {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == objectValue,
+                      "in Json::Value::find(begin, end): requires "
+                      "objectValue or nullValue");
+  if (type() == nullValue)
+    return nullptr;
+  CZString actualKey(begin, static_cast<unsigned>(end - begin),
+                     CZString::noDuplication);
   ObjectValues::const_iterator it = value_.map_->find(actualKey);
-  if (it == value_.map_->end()) return NULL;
+  if (it == value_.map_->end())
+    return nullptr;
   return &(*it).second;
 }
-const Value& Value::operator[](const char* key) const
-{
+Value* Value::demand(char const* begin, char const* end) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == objectValue,
+                      "in Json::Value::demand(begin, end): requires "
+                      "objectValue or nullValue");
+  return &resolveReference(begin, end);
+}
+const Value& Value::operator[](const char* key) const {
   Value const* found = find(key, key + strlen(key));
-  if (!found) return nullSingleton();
+  if (!found)
+    return nullSingleton();
   return *found;
 }
-Value const& Value::operator[](JSONCPP_STRING const& key) const
-{
+Value const& Value::operator[](const String& key) const {
   Value const* found = find(key.data(), key.data() + key.length());
-  if (!found) return nullSingleton();
+  if (!found)
+    return nullSingleton();
   return *found;
 }
 
@@ -1125,7 +1114,7 @@ Value& Value::operator[](const char* key) {
   return resolveReference(key, key + strlen(key));
 }
 
-Value& Value::operator[](const JSONCPP_STRING& key) {
+Value& Value::operator[](const String& key) {
   return resolveReference(key.data(), key.data() + key.length());
 }
 
@@ -1133,179 +1122,140 @@ Value& Value::operator[](const StaticString& key) {
   return resolveReference(key.c_str());
 }
 
-#ifdef JSON_USE_CPPTL
-Value& Value::operator[](const CppTL::ConstString& key) {
-  return resolveReference(key.c_str(), key.end_c_str());
-}
-Value const& Value::operator[](CppTL::ConstString const& key) const
-{
-  Value const* found = find(key.c_str(), key.end_c_str());
-  if (!found) return nullSingleton();
-  return *found;
+Value& Value::append(const Value& value) { return append(Value(value)); }
+
+Value& Value::append(Value&& value) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == arrayValue,
+                      "in Json::Value::append: requires arrayValue");
+  if (type() == nullValue) {
+    *this = Value(arrayValue);
+  }
+  return this->value_.map_->emplace(size(), std::move(value)).first->second;
 }
-#endif
 
-Value& Value::append(const Value& value) { return (*this)[size()] = value; }
+bool Value::insert(ArrayIndex index, const Value& newValue) {
+  return insert(index, Value(newValue));
+}
 
-#if JSON_HAS_RVALUE_REFERENCES
-  Value& Value::append(Value&& value) { return (*this)[size()] = value; }
-#endif
+bool Value::insert(ArrayIndex index, Value&& newValue) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == arrayValue,
+                      "in Json::Value::insert: requires arrayValue");
+  ArrayIndex length = size();
+  if (index > length) {
+    return false;
+  }
+  for (ArrayIndex i = length; i > index; i--) {
+    (*this)[i] = std::move((*this)[i - 1]);
+  }
+  (*this)[index] = std::move(newValue);
+  return true;
+}
 
-Value Value::get(char const* key, char const* cend, Value const& defaultValue) const
-{
-  Value const* found = find(key, cend);
+Value Value::get(char const* begin, char const* end,
+                 Value const& defaultValue) const {
+  Value const* found = find(begin, end);
   return !found ? defaultValue : *found;
 }
-Value Value::get(char const* key, Value const& defaultValue) const
-{
+Value Value::get(char const* key, Value const& defaultValue) const {
   return get(key, key + strlen(key), defaultValue);
 }
-Value Value::get(JSONCPP_STRING const& key, Value const& defaultValue) const
-{
+Value Value::get(String const& key, Value const& defaultValue) const {
   return get(key.data(), key.data() + key.length(), defaultValue);
 }
 
-
-bool Value::removeMember(const char* key, const char* cend, Value* removed)
-{
-  if (type_ != objectValue) {
+bool Value::removeMember(const char* begin, const char* end, Value* removed) {
+  if (type() != objectValue) {
     return false;
   }
-  CZString actualKey(key, static_cast<unsigned>(cend-key), CZString::noDuplication);
-  ObjectValues::iterator it = value_.map_->find(actualKey);
+  CZString actualKey(begin, static_cast<unsigned>(end - begin),
+                     CZString::noDuplication);
+  auto it = value_.map_->find(actualKey);
   if (it == value_.map_->end())
     return false;
-  *removed = it->second;
+  if (removed)
+    *removed = std::move(it->second);
   value_.map_->erase(it);
   return true;
 }
-bool Value::removeMember(const char* key, Value* removed)
-{
+bool Value::removeMember(const char* key, Value* removed) {
   return removeMember(key, key + strlen(key), removed);
 }
-bool Value::removeMember(JSONCPP_STRING const& key, Value* removed)
-{
+bool Value::removeMember(String const& key, Value* removed) {
   return removeMember(key.data(), key.data() + key.length(), removed);
 }
-Value Value::removeMember(const char* key)
-{
-  JSON_ASSERT_MESSAGE(type_ == nullValue || type_ == objectValue,
+void Value::removeMember(const char* key) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == objectValue,
                       "in Json::Value::removeMember(): requires objectValue");
-  if (type_ == nullValue)
-    return nullSingleton();
+  if (type() == nullValue)
+    return;
 
-  Value removed;  // null
-  removeMember(key, key + strlen(key), &removed);
-  return removed; // still null if removeMember() did nothing
-}
-Value Value::removeMember(const JSONCPP_STRING& key)
-{
-  return removeMember(key.c_str());
+  CZString actualKey(key, unsigned(strlen(key)), CZString::noDuplication);
+  value_.map_->erase(actualKey);
 }
+void Value::removeMember(const String& key) { removeMember(key.c_str()); }
 
 bool Value::removeIndex(ArrayIndex index, Value* removed) {
-  if (type_ != arrayValue) {
+  if (type() != arrayValue) {
     return false;
   }
   CZString key(index);
-  ObjectValues::iterator it = value_.map_->find(key);
+  auto it = value_.map_->find(key);
   if (it == value_.map_->end()) {
     return false;
   }
-  *removed = it->second;
+  if (removed)
+    *removed = it->second;
   ArrayIndex oldSize = size();
   // shift left all items left, into the place of the "removed"
-  for (ArrayIndex i = index; i < (oldSize - 1); ++i){
+  for (ArrayIndex i = index; i < (oldSize - 1); ++i) {
     CZString keey(i);
     (*value_.map_)[keey] = (*this)[i + 1];
   }
   // erase the last one ("leftover")
   CZString keyLast(oldSize - 1);
-  ObjectValues::iterator itLast = value_.map_->find(keyLast);
+  auto itLast = value_.map_->find(keyLast);
   value_.map_->erase(itLast);
   return true;
 }
 
-#ifdef JSON_USE_CPPTL
-Value Value::get(const CppTL::ConstString& key,
-                 const Value& defaultValue) const {
-  return get(key.c_str(), key.end_c_str(), defaultValue);
+bool Value::isMember(char const* begin, char const* end) const {
+  Value const* value = find(begin, end);
+  return nullptr != value;
 }
-#endif
-
-bool Value::isMember(char const* key, char const* cend) const
-{
-  Value const* value = find(key, cend);
-  return NULL != value;
-}
-bool Value::isMember(char const* key) const
-{
+bool Value::isMember(char const* key) const {
   return isMember(key, key + strlen(key));
 }
-bool Value::isMember(JSONCPP_STRING const& key) const
-{
+bool Value::isMember(String const& key) const {
   return isMember(key.data(), key.data() + key.length());
 }
 
-#ifdef JSON_USE_CPPTL
-bool Value::isMember(const CppTL::ConstString& key) const {
-  return isMember(key.c_str(), key.end_c_str());
-}
-#endif
-
 Value::Members Value::getMemberNames() const {
   JSON_ASSERT_MESSAGE(
-      type_ == nullValue || type_ == objectValue,
+      type() == nullValue || type() == objectValue,
       "in Json::Value::getMemberNames(), value must be objectValue");
-  if (type_ == nullValue)
+  if (type() == nullValue)
     return Value::Members();
   Members members;
   members.reserve(value_.map_->size());
   ObjectValues::const_iterator it = value_.map_->begin();
   ObjectValues::const_iterator itEnd = value_.map_->end();
   for (; it != itEnd; ++it) {
-    members.push_back(JSONCPP_STRING((*it).first.data(),
-                                  (*it).first.length()));
+    members.push_back(String((*it).first.data(), (*it).first.length()));
   }
   return members;
 }
-//
-//# ifdef JSON_USE_CPPTL
-// EnumMemberNames
-// Value::enumMemberNames() const
-//{
-//   if ( type_ == objectValue )
-//   {
-//      return CppTL::Enum::any(  CppTL::Enum::transform(
-//         CppTL::Enum::keys( *(value_.map_), CppTL::Type<const CZString &>() ),
-//         MemberNamesTransform() ) );
-//   }
-//   return EnumMemberNames();
-//}
-//
-//
-// EnumValues
-// Value::enumValues() const
-//{
-//   if ( type_ == objectValue  ||  type_ == arrayValue )
-//      return CppTL::Enum::anyValues( *(value_.map_),
-//                                     CppTL::Type<const Value &>() );
-//   return EnumValues();
-//}
-//
-//# endif
 
 static bool IsIntegral(double d) {
   double integral_part;
   return modf(d, &integral_part) == 0.0;
 }
 
-bool Value::isNull() const { return type_ == nullValue; }
+bool Value::isNull() const { return type() == nullValue; }
 
-bool Value::isBool() const { return type_ == booleanValue; }
+bool Value::isBool() const { return type() == booleanValue; }
 
 bool Value::isInt() const {
-  switch (type_) {
+  switch (type()) {
   case intValue:
 #if defined(JSON_HAS_INT64)
     return value_.int_ >= minInt && value_.int_ <= maxInt;
@@ -1324,7 +1274,7 @@ bool Value::isInt() const {
 }
 
 bool Value::isUInt() const {
-  switch (type_) {
+  switch (type()) {
   case intValue:
 #if defined(JSON_HAS_INT64)
     return value_.int_ >= 0 && LargestUInt(value_.int_) <= LargestUInt(maxUInt);
@@ -1348,7 +1298,7 @@ bool Value::isUInt() const {
 
 bool Value::isInt64() const {
 #if defined(JSON_HAS_INT64)
-  switch (type_) {
+  switch (type()) {
   case intValue:
     return true;
   case uintValue:
@@ -1368,7 +1318,7 @@ bool Value::isInt64() const {
 
 bool Value::isUInt64() const {
 #if defined(JSON_HAS_INT64)
-  switch (type_) {
+  switch (type()) {
   case intValue:
     return value_.int_ >= 0;
   case uintValue:
@@ -1387,61 +1337,92 @@ bool Value::isUInt64() const {
 }
 
 bool Value::isIntegral() const {
-  switch (type_) {
-    case intValue:
-    case uintValue:
-      return true;
-    case realValue:
+  switch (type()) {
+  case intValue:
+  case uintValue:
+    return true;
+  case realValue:
 #if defined(JSON_HAS_INT64)
-      // Note that maxUInt64 (= 2^64 - 1) is not exactly representable as a
-      // double, so double(maxUInt64) will be rounded up to 2^64. Therefore we
-      // require the value to be strictly less than the limit.
-      return value_.real_ >= double(minInt64) && value_.real_ < maxUInt64AsDouble && IsIntegral(value_.real_);
+    // Note that maxUInt64 (= 2^64 - 1) is not exactly representable as a
+    // double, so double(maxUInt64) will be rounded up to 2^64. Therefore we
+    // require the value to be strictly less than the limit.
+    return value_.real_ >= double(minInt64) &&
+           value_.real_ < maxUInt64AsDouble && IsIntegral(value_.real_);
 #else
-      return value_.real_ >= minInt && value_.real_ <= maxUInt && IsIntegral(value_.real_);
+    return value_.real_ >= minInt && value_.real_ <= maxUInt &&
+           IsIntegral(value_.real_);
 #endif // JSON_HAS_INT64
-    default:
-      break;
+  default:
+    break;
   }
   return false;
 }
 
-bool Value::isDouble() const { return type_ == intValue || type_ == uintValue || type_ == realValue; }
+bool Value::isDouble() const {
+  return type() == intValue || type() == uintValue || type() == realValue;
+}
 
 bool Value::isNumeric() const { return isDouble(); }
 
-bool Value::isString() const { return type_ == stringValue; }
+bool Value::isString() const { return type() == stringValue; }
 
-bool Value::isArray() const { return type_ == arrayValue; }
+bool Value::isArray() const { return type() == arrayValue; }
 
-bool Value::isObject() const { return type_ == objectValue; }
+bool Value::isObject() const { return type() == objectValue; }
 
-void Value::setComment(const char* comment, size_t len, CommentPlacement placement) {
-  if (!comments_)
-    comments_ = new CommentInfo[numberOfCommentPlacement];
-  if ((len > 0) && (comment[len-1] == '\n')) {
-    // Always discard trailing newline, to aid indentation.
-    len -= 1;
-  }
-  comments_[placement].setComment(comment, len);
+Value::Comments::Comments(const Comments& that)
+    : ptr_{cloneUnique(that.ptr_)} {}
+
+Value::Comments::Comments(Comments&& that) : ptr_{std::move(that.ptr_)} {}
+
+Value::Comments& Value::Comments::operator=(const Comments& that) {
+  ptr_ = cloneUnique(that.ptr_);
+  return *this;
 }
 
-void Value::setComment(const char* comment, CommentPlacement placement) {
-  setComment(comment, strlen(comment), placement);
+Value::Comments& Value::Comments::operator=(Comments&& that) {
+  ptr_ = std::move(that.ptr_);
+  return *this;
+}
+
+bool Value::Comments::has(CommentPlacement slot) const {
+  return ptr_ && !(*ptr_)[slot].empty();
 }
 
-void Value::setComment(const JSONCPP_STRING& comment, CommentPlacement placement) {
-  setComment(comment.c_str(), comment.length(), placement);
+String Value::Comments::get(CommentPlacement slot) const {
+  if (!ptr_)
+    return {};
+  return (*ptr_)[slot];
+}
+
+void Value::Comments::set(CommentPlacement slot, String comment) {
+  if (!ptr_) {
+    ptr_ = std::unique_ptr<Array>(new Array());
+  }
+  // check comments array boundry.
+  if (slot < CommentPlacement::numberOfCommentPlacement) {
+    (*ptr_)[slot] = std::move(comment);
+  }
+}
+
+void Value::setComment(String comment, CommentPlacement placement) {
+  if (!comment.empty() && (comment.back() == '\n')) {
+    // Always discard trailing newline, to aid indentation.
+    comment.pop_back();
+  }
+  JSON_ASSERT(!comment.empty());
+  JSON_ASSERT_MESSAGE(
+      comment[0] == '\0' || comment[0] == '/',
+      "in Json::Value::setComment(): Comments must start with /");
+  comments_.set(placement, std::move(comment));
 }
 
 bool Value::hasComment(CommentPlacement placement) const {
-  return comments_ != 0 && comments_[placement].comment_ != 0;
+  return comments_.has(placement);
 }
 
-JSONCPP_STRING Value::getComment(CommentPlacement placement) const {
-  if (hasComment(placement))
-    return comments_[placement].comment_;
-  return "";
+String Value::getComment(CommentPlacement placement) const {
+  return comments_.get(placement);
 }
 
 void Value::setOffsetStart(ptrdiff_t start) { start_ = start; }
@@ -1452,18 +1433,18 @@ ptrdiff_t Value::getOffsetStart() const { return start_; }
 
 ptrdiff_t Value::getOffsetLimit() const { return limit_; }
 
-JSONCPP_STRING Value::toStyledString() const {
+String Value::toStyledString() const {
   StreamWriterBuilder builder;
 
-  JSONCPP_STRING out = this->hasComment(commentBefore) ? "\n" : "";
+  String out = this->hasComment(commentBefore) ? "\n" : "";
   out += Json::writeString(builder, *this);
-  out += "\n";
+  out += '\n';
 
   return out;
 }
 
 Value::const_iterator Value::begin() const {
-  switch (type_) {
+  switch (type()) {
   case arrayValue:
   case objectValue:
     if (value_.map_)
@@ -1472,11 +1453,11 @@ Value::const_iterator Value::begin() const {
   default:
     break;
   }
-  return const_iterator();
+  return {};
 }
 
 Value::const_iterator Value::end() const {
-  switch (type_) {
+  switch (type()) {
   case arrayValue:
   case objectValue:
     if (value_.map_)
@@ -1485,11 +1466,11 @@ Value::const_iterator Value::end() const {
   default:
     break;
   }
-  return const_iterator();
+  return {};
 }
 
 Value::iterator Value::begin() {
-  switch (type_) {
+  switch (type()) {
   case arrayValue:
   case objectValue:
     if (value_.map_)
@@ -1502,7 +1483,7 @@ Value::iterator Value::begin() {
 }
 
 Value::iterator Value::end() {
-  switch (type_) {
+  switch (type()) {
   case arrayValue:
   case objectValue:
     if (value_.map_)
@@ -1517,25 +1498,20 @@ Value::iterator Value::end() {
 // class PathArgument
 // //////////////////////////////////////////////////////////////////
 
-PathArgument::PathArgument() : key_(), index_(), kind_(kindNone) {}
+PathArgument::PathArgument() = default;
 
 PathArgument::PathArgument(ArrayIndex index)
-    : key_(), index_(index), kind_(kindIndex) {}
+    : index_(index), kind_(kindIndex) {}
 
-PathArgument::PathArgument(const char* key)
-    : key_(key), index_(), kind_(kindKey) {}
+PathArgument::PathArgument(const char* key) : key_(key), kind_(kindKey) {}
 
-PathArgument::PathArgument(const JSONCPP_STRING& key)
-    : key_(key.c_str()), index_(), kind_(kindKey) {}
+PathArgument::PathArgument(String key) : key_(std::move(key)), kind_(kindKey) {}
 
 // class Path
 // //////////////////////////////////////////////////////////////////
 
-Path::Path(const JSONCPP_STRING& path,
-           const PathArgument& a1,
-           const PathArgument& a2,
-           const PathArgument& a3,
-           const PathArgument& a4,
+Path::Path(const String& path, const PathArgument& a1, const PathArgument& a2,
+           const PathArgument& a3, const PathArgument& a4,
            const PathArgument& a5) {
   InArgs in;
   in.reserve(5);
@@ -1547,10 +1523,10 @@ Path::Path(const JSONCPP_STRING& path,
   makePath(path, in);
 }
 
-void Path::makePath(const JSONCPP_STRING& path, const InArgs& in) {
+void Path::makePath(const String& path, const InArgs& in) {
   const char* current = path.c_str();
   const char* end = current + path.length();
-  InArgs::const_iterator itInArg = in.begin();
+  auto itInArg = in.begin();
   while (current != end) {
     if (*current == '[') {
       ++current;
@@ -1573,13 +1549,12 @@ void Path::makePath(const JSONCPP_STRING& path, const InArgs& in) {
       const char* beginName = current;
       while (current != end && !strchr("[.", *current))
         ++current;
-      args_.push_back(JSONCPP_STRING(beginName, current));
+      args_.push_back(String(beginName, current));
     }
   }
 }
 
-void Path::addPathInArg(const JSONCPP_STRING& /*path*/,
-                        const InArgs& in,
+void Path::addPathInArg(const String& /*path*/, const InArgs& in,
                         InArgs::const_iterator& itInArg,
                         PathArgument::Kind kind) {
   if (itInArg == in.end()) {
@@ -1591,30 +1566,29 @@ void Path::addPathInArg(const JSONCPP_STRING& /*path*/,
   }
 }
 
-void Path::invalidPath(const JSONCPP_STRING& /*path*/, int /*location*/) {
+void Path::invalidPath(const String& /*path*/, int /*location*/) {
   // Error: invalid path.
 }
 
 const Value& Path::resolve(const Value& root) const {
   const Value* node = &root;
-  for (Args::const_iterator it = args_.begin(); it != args_.end(); ++it) {
-    const PathArgument& arg = *it;
+  for (const auto& arg : args_) {
     if (arg.kind_ == PathArgument::kindIndex) {
       if (!node->isArray() || !node->isValidIndex(arg.index_)) {
-        // Error: unable to resolve path (array value expected at position...
-        return Value::null;
+        // Error: unable to resolve path (array value expected at position... )
+        return Value::nullSingleton();
       }
       node = &((*node)[arg.index_]);
     } else if (arg.kind_ == PathArgument::kindKey) {
       if (!node->isObject()) {
         // Error: unable to resolve path (object value expected at position...)
-        return Value::null;
+        return Value::nullSingleton();
       }
       node = &((*node)[arg.key_]);
       if (node == &Value::nullSingleton()) {
         // Error: unable to resolve path (object has no member named '' at
         // position...)
-        return Value::null;
+        return Value::nullSingleton();
       }
     }
   }
@@ -1623,8 +1597,7 @@ const Value& Path::resolve(const Value& root) const {
 
 Value Path::resolve(const Value& root, const Value& defaultValue) const {
   const Value* node = &root;
-  for (Args::const_iterator it = args_.begin(); it != args_.end(); ++it) {
-    const PathArgument& arg = *it;
+  for (const auto& arg : args_) {
     if (arg.kind_ == PathArgument::kindIndex) {
       if (!node->isArray() || !node->isValidIndex(arg.index_))
         return defaultValue;
@@ -1642,8 +1615,7 @@ Value Path::resolve(const Value& root, const Value& defaultValue) const {
 
 Value& Path::make(Value& root) const {
   Value* node = &root;
-  for (Args::const_iterator it = args_.begin(); it != args_.end(); ++it) {
-    const PathArgument& arg = *it;
+  for (const auto& arg : args_) {
     if (arg.kind_ == PathArgument::kindIndex) {
       if (!node->isArray()) {
         // Error: node is not an array at position ...