Update jsoncpp to 1.9.4 (#10477)

Co-authored-by: Zughy <4279489-marco_a@users.noreply.gitlab.com>

3 files changed, 1122 insertions, 872 deletions

diff --git a/lib/jsoncpp/json/UPDATING b/lib/jsoncpp/json/UPDATING
index f0226e8ee..0893244cf 100644
--- a/lib/jsoncpp/json/UPDATING
+++ b/lib/jsoncpp/json/UPDATING
@@ -1,6 +1,6 @@
 #!/bin/sh
 cd ..
-git clone https://github.com/open-source-parsers/jsoncpp -b 1.8.3 --depth 1
+git clone https://github.com/open-source-parsers/jsoncpp -b 1.9.4 --depth 1
 cd jsoncpp
 python amalgamate.py
 cp -R dist/json ../json
diff --git a/lib/jsoncpp/json/json-forwards.h b/lib/jsoncpp/json/json-forwards.h
index de2e4bd79..d3260c57c 100644
--- a/lib/jsoncpp/json/json-forwards.h
+++ b/lib/jsoncpp/json/json-forwards.h
@@ -80,6 +80,151 @@ license you like.
 #define JSON_IS_AMALGAMATION
 
 // //////////////////////////////////////////////////////////////////////
+// Beginning of content of file: include/json/version.h
+// //////////////////////////////////////////////////////////////////////
+
+#ifndef JSON_VERSION_H_INCLUDED
+#define JSON_VERSION_H_INCLUDED
+
+// Note: version must be updated in three places when doing a release. This
+// annoying process ensures that amalgamate, CMake, and meson all report the
+// correct version.
+// 1. /meson.build
+// 2. /include/json/version.h
+// 3. /CMakeLists.txt
+// IMPORTANT: also update the SOVERSION!!
+
+#define JSONCPP_VERSION_STRING "1.9.4"
+#define JSONCPP_VERSION_MAJOR 1
+#define JSONCPP_VERSION_MINOR 9
+#define JSONCPP_VERSION_PATCH 3
+#define JSONCPP_VERSION_QUALIFIER
+#define JSONCPP_VERSION_HEXA                                                   \
+  ((JSONCPP_VERSION_MAJOR << 24) | (JSONCPP_VERSION_MINOR << 16) |             \
+   (JSONCPP_VERSION_PATCH << 8))
+
+#ifdef JSONCPP_USING_SECURE_MEMORY
+#undef JSONCPP_USING_SECURE_MEMORY
+#endif
+#define JSONCPP_USING_SECURE_MEMORY 0
+// If non-zero, the library zeroes any memory that it has allocated before
+// it frees its memory.
+
+#endif // JSON_VERSION_H_INCLUDED
+
+// //////////////////////////////////////////////////////////////////////
+// End of content of file: include/json/version.h
+// //////////////////////////////////////////////////////////////////////
+
+
+
+
+
+
+// //////////////////////////////////////////////////////////////////////
+// Beginning of content of file: include/json/allocator.h
+// //////////////////////////////////////////////////////////////////////
+
+// 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_ALLOCATOR_H_INCLUDED
+#define JSON_ALLOCATOR_H_INCLUDED
+
+#include <cstring>
+#include <memory>
+
+#pragma pack(push, 8)
+
+namespace Json {
+template <typename T> class SecureAllocator {
+public:
+  // Type definitions
+  using value_type = T;
+  using pointer = T*;
+  using const_pointer = const T*;
+  using reference = T&;
+  using const_reference = const T&;
+  using size_type = std::size_t;
+  using difference_type = std::ptrdiff_t;
+
+  /**
+   * Allocate memory for N items using the standard allocator.
+   */
+  pointer allocate(size_type n) {
+    // allocate using "global operator new"
+    return static_cast<pointer>(::operator new(n * sizeof(T)));
+  }
+
+  /**
+   * Release memory which was allocated for N items at pointer P.
+   *
+   * The memory block is filled with zeroes before being released.
+   * The pointer argument is tagged as "volatile" to prevent the
+   * compiler optimizing out this critical step.
+   */
+  void deallocate(volatile pointer p, size_type n) {
+    std::memset(p, 0, n * sizeof(T));
+    // free using "global operator delete"
+    ::operator delete(p);
+  }
+
+  /**
+   * Construct an item in-place at pointer P.
+   */
+  template <typename... Args> void construct(pointer p, Args&&... args) {
+    // construct using "placement new" and "perfect forwarding"
+    ::new (static_cast<void*>(p)) T(std::forward<Args>(args)...);
+  }
+
+  size_type max_size() const { return size_t(-1) / sizeof(T); }
+
+  pointer address(reference x) const { return std::addressof(x); }
+
+  const_pointer address(const_reference x) const { return std::addressof(x); }
+
+  /**
+   * Destroy an item in-place at pointer P.
+   */
+  void destroy(pointer p) {
+    // destroy using "explicit destructor"
+    p->~T();
+  }
+
+  // Boilerplate
+  SecureAllocator() {}
+  template <typename U> SecureAllocator(const SecureAllocator<U>&) {}
+  template <typename U> struct rebind { using other = SecureAllocator<U>; };
+};
+
+template <typename T, typename U>
+bool operator==(const SecureAllocator<T>&, const SecureAllocator<U>&) {
+  return true;
+}
+
+template <typename T, typename U>
+bool operator!=(const SecureAllocator<T>&, const SecureAllocator<U>&) {
+  return false;
+}
+
+} // namespace Json
+
+#pragma pack(pop)
+
+#endif // JSON_ALLOCATOR_H_INCLUDED
+
+// //////////////////////////////////////////////////////////////////////
+// End of content of file: include/json/allocator.h
+// //////////////////////////////////////////////////////////////////////
+
+
+
+
+
+
+// //////////////////////////////////////////////////////////////////////
 // Beginning of content of file: include/json/config.h
 // //////////////////////////////////////////////////////////////////////
 
@@ -90,19 +235,14 @@ license you like.
 
 #ifndef JSON_CONFIG_H_INCLUDED
 #define JSON_CONFIG_H_INCLUDED
-#include <stddef.h>
-#include <string> //typedef String
-#include <stdint.h> //typedef int64_t, uint64_t
-
-/// If defined, indicates that json library is embedded in CppTL library.
-//# define JSON_IN_CPPTL 1
-
-/// If defined, indicates that json may leverage CppTL library
-//#  define JSON_USE_CPPTL 1
-/// If defined, indicates that cpptl vector based map should be used instead of
-/// std::map
-/// as Value container.
-//#  define JSON_USE_CPPTL_SMALLMAP 1
+#include <cstddef>
+#include <cstdint>
+#include <istream>
+#include <memory>
+#include <ostream>
+#include <sstream>
+#include <string>
+#include <type_traits>
 
 // If non-zero, the library uses exceptions to report bad input instead of C
 // assertion macros. The default is to use exceptions.
@@ -110,164 +250,132 @@ license you like.
 #define JSON_USE_EXCEPTION 1
 #endif
 
+// Temporary, tracked for removal with issue #982.
+#ifndef JSON_USE_NULLREF
+#define JSON_USE_NULLREF 1
+#endif
+
 /// If defined, indicates that the source file is amalgamated
 /// to prevent private header inclusion.
 /// Remarks: it is automatically defined in the generated amalgamated header.
 // #define JSON_IS_AMALGAMATION
 
-#ifdef JSON_IN_CPPTL
-#include <cpptl/config.h>
-#ifndef JSON_USE_CPPTL
-#define JSON_USE_CPPTL 1
-#endif
-#endif
-
-#ifdef JSON_IN_CPPTL
-#define JSON_API CPPTL_API
-#elif defined(JSON_DLL_BUILD)
+// Export macros for DLL visibility
+#if defined(JSON_DLL_BUILD)
 #if defined(_MSC_VER) || defined(__MINGW32__)
 #define JSON_API __declspec(dllexport)
 #define JSONCPP_DISABLE_DLL_INTERFACE_WARNING
+#elif defined(__GNUC__) || defined(__clang__)
+#define JSON_API __attribute__((visibility("default")))
 #endif // if defined(_MSC_VER)
+
 #elif defined(JSON_DLL)
 #if defined(_MSC_VER) || defined(__MINGW32__)
 #define JSON_API __declspec(dllimport)
 #define JSONCPP_DISABLE_DLL_INTERFACE_WARNING
 #endif // if defined(_MSC_VER)
-#endif // ifdef JSON_IN_CPPTL
+#endif // ifdef JSON_DLL_BUILD
+
 #if !defined(JSON_API)
 #define JSON_API
 #endif
 
-// If JSON_NO_INT64 is defined, then Json only support C++ "int" type for
-// integer
-// Storages, and 64 bits integer support is disabled.
-// #define JSON_NO_INT64 1
+#if defined(_MSC_VER) && _MSC_VER < 1800
+#error                                                                         \
+    "ERROR:  Visual Studio 12 (2013) with _MSC_VER=1800 is the oldest supported compiler with sufficient C++11 capabilities"
+#endif
 
-#if defined(_MSC_VER) // MSVC
-#  if _MSC_VER <= 1200 // MSVC 6
-    // Microsoft Visual Studio 6 only support conversion from __int64 to double
-    // (no conversion from unsigned __int64).
-#    define JSON_USE_INT64_DOUBLE_CONVERSION 1
-    // Disable warning 4786 for VS6 caused by STL (identifier was truncated to '255'
-    // characters in the debug information)
-    // All projects I've ever seen with VS6 were using this globally (not bothering
-    // with pragma push/pop).
-#    pragma warning(disable : 4786)
-#  endif // MSVC 6
-
-#  if _MSC_VER >= 1500 // MSVC 2008
-    /// Indicates that the following function is deprecated.
-#    define JSONCPP_DEPRECATED(message) __declspec(deprecated(message))
-#  endif
-
-#endif // defined(_MSC_VER)
-
-// In c++11 the override keyword allows you to explicitly define that a function
-// is intended to override the base-class version.  This makes the code more
-// managable and fixes a set of common hard-to-find bugs.
-#if __cplusplus >= 201103L
-# define JSONCPP_OVERRIDE override
-# define JSONCPP_NOEXCEPT noexcept
-#elif defined(_MSC_VER) && _MSC_VER > 1600 && _MSC_VER < 1900
-# define JSONCPP_OVERRIDE override
-# define JSONCPP_NOEXCEPT throw()
-#elif defined(_MSC_VER) && _MSC_VER >= 1900
-# define JSONCPP_OVERRIDE override
-# define JSONCPP_NOEXCEPT noexcept
+#if defined(_MSC_VER) && _MSC_VER < 1900
+// As recommended at
+// https://stackoverflow.com/questions/2915672/snprintf-and-visual-studio-2010
+extern JSON_API int msvc_pre1900_c99_snprintf(char* outBuf, size_t size,
+                                              const char* format, ...);
+#define jsoncpp_snprintf msvc_pre1900_c99_snprintf
 #else
-# define JSONCPP_OVERRIDE
-# define JSONCPP_NOEXCEPT throw()
+#define jsoncpp_snprintf std::snprintf
 #endif
 
-#ifndef JSON_HAS_RVALUE_REFERENCES
+// If JSON_NO_INT64 is defined, then Json only support C++ "int" type for
+// integer
+// Storages, and 64 bits integer support is disabled.
+// #define JSON_NO_INT64 1
 
-#if defined(_MSC_VER) && _MSC_VER >= 1600 // MSVC >= 2010
-#define JSON_HAS_RVALUE_REFERENCES 1
-#endif // MSVC >= 2010
+// JSONCPP_OVERRIDE is maintained for backwards compatibility of external tools.
+// C++11 should be used directly in JSONCPP.
+#define JSONCPP_OVERRIDE override
 
 #ifdef __clang__
-#if __has_feature(cxx_rvalue_references)
-#define JSON_HAS_RVALUE_REFERENCES 1
-#endif  // has_feature
-
-#elif defined __GNUC__ // not clang (gcc comes later since clang emulates gcc)
-#if defined(__GXX_EXPERIMENTAL_CXX0X__) || (__cplusplus >= 201103L)
-#define JSON_HAS_RVALUE_REFERENCES 1
-#endif  // GXX_EXPERIMENTAL
-
-#endif // __clang__ || __GNUC__
-
-#endif // not defined JSON_HAS_RVALUE_REFERENCES
-
-#ifndef JSON_HAS_RVALUE_REFERENCES
-#define JSON_HAS_RVALUE_REFERENCES 0
+#if __has_extension(attribute_deprecated_with_message)
+#define JSONCPP_DEPRECATED(message) __attribute__((deprecated(message)))
 #endif
-
-#ifdef __clang__
-#  if __has_extension(attribute_deprecated_with_message)
-#    define JSONCPP_DEPRECATED(message)  __attribute__ ((deprecated(message)))
-#  endif
-#elif defined __GNUC__ // not clang (gcc comes later since clang emulates gcc)
-#  if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))
-#    define JSONCPP_DEPRECATED(message)  __attribute__ ((deprecated(message)))
-#  elif (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
-#    define JSONCPP_DEPRECATED(message)  __attribute__((__deprecated__))
-#  endif  // GNUC version
-#endif // __clang__ || __GNUC__
+#elif defined(__GNUC__) // not clang (gcc comes later since clang emulates gcc)
+#if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))
+#define JSONCPP_DEPRECATED(message) __attribute__((deprecated(message)))
+#elif (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
+#define JSONCPP_DEPRECATED(message) __attribute__((__deprecated__))
+#endif                  // GNUC version
+#elif defined(_MSC_VER) // MSVC (after clang because clang on Windows emulates
+                        // MSVC)
+#define JSONCPP_DEPRECATED(message) __declspec(deprecated(message))
+#endif // __clang__ || __GNUC__ || _MSC_VER
 
 #if !defined(JSONCPP_DEPRECATED)
 #define JSONCPP_DEPRECATED(message)
 #endif // if !defined(JSONCPP_DEPRECATED)
 
-#if __GNUC__ >= 6
-#  define JSON_USE_INT64_DOUBLE_CONVERSION 1
+#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 6))
+#define JSON_USE_INT64_DOUBLE_CONVERSION 1
 #endif
 
 #if !defined(JSON_IS_AMALGAMATION)
 
-# include "version.h"
-
-# if JSONCPP_USING_SECURE_MEMORY
-#  include "allocator.h" //typedef Allocator
-# endif
+#include "allocator.h"
+#include "version.h"
 
 #endif // if !defined(JSON_IS_AMALGAMATION)
 
 namespace Json {
-typedef int Int;
-typedef unsigned int UInt;
+using Int = int;
+using UInt = unsigned int;
 #if defined(JSON_NO_INT64)
-typedef int LargestInt;
-typedef unsigned int LargestUInt;
+using LargestInt = int;
+using LargestUInt = unsigned int;
 #undef JSON_HAS_INT64
 #else                 // if defined(JSON_NO_INT64)
 // For Microsoft Visual use specific types as long long is not supported
 #if defined(_MSC_VER) // Microsoft Visual Studio
-typedef __int64 Int64;
-typedef unsigned __int64 UInt64;
+using Int64 = __int64;
+using UInt64 = unsigned __int64;
 #else                 // if defined(_MSC_VER) // Other platforms, use long long
-typedef int64_t Int64;
-typedef uint64_t UInt64;
-#endif // if defined(_MSC_VER)
-typedef Int64 LargestInt;
-typedef UInt64 LargestUInt;
+using Int64 = int64_t;
+using UInt64 = uint64_t;
+#endif                // if defined(_MSC_VER)
+using LargestInt = Int64;
+using LargestUInt = UInt64;
 #define JSON_HAS_INT64
 #endif // if defined(JSON_NO_INT64)
-#if JSONCPP_USING_SECURE_MEMORY
-#define JSONCPP_STRING        std::basic_string<char, std::char_traits<char>, Json::SecureAllocator<char> >
-#define JSONCPP_OSTRINGSTREAM std::basic_ostringstream<char, std::char_traits<char>, Json::SecureAllocator<char> >
-#define JSONCPP_OSTREAM       std::basic_ostream<char, std::char_traits<char>>
-#define JSONCPP_ISTRINGSTREAM std::basic_istringstream<char, std::char_traits<char>, Json::SecureAllocator<char> >
-#define JSONCPP_ISTREAM       std::istream
-#else
-#define JSONCPP_STRING        std::string
-#define JSONCPP_OSTRINGSTREAM std::ostringstream
-#define JSONCPP_OSTREAM       std::ostream
-#define JSONCPP_ISTRINGSTREAM std::istringstream
-#define JSONCPP_ISTREAM       std::istream
-#endif // if JSONCPP_USING_SECURE_MEMORY
-} // end namespace Json
+
+template <typename T>
+using Allocator =
+    typename std::conditional<JSONCPP_USING_SECURE_MEMORY, SecureAllocator<T>,
+                              std::allocator<T>>::type;
+using String = std::basic_string<char, std::char_traits<char>, Allocator<char>>;
+using IStringStream =
+    std::basic_istringstream<String::value_type, String::traits_type,
+                             String::allocator_type>;
+using OStringStream =
+    std::basic_ostringstream<String::value_type, String::traits_type,
+                             String::allocator_type>;
+using IStream = std::istream;
+using OStream = std::ostream;
+} // namespace Json
+
+// Legacy names (formerly macros).
+using JSONCPP_STRING = Json::String;
+using JSONCPP_ISTRINGSTREAM = Json::IStringStream;
+using JSONCPP_OSTRINGSTREAM = Json::OStringStream;
+using JSONCPP_ISTREAM = Json::IStream;
+using JSONCPP_OSTREAM = Json::OStream;
 
 #endif // JSON_CONFIG_H_INCLUDED
 
@@ -299,17 +407,23 @@ typedef UInt64 LargestUInt;
 namespace Json {
 
 // writer.h
+class StreamWriter;
+class StreamWriterBuilder;
+class Writer;
 class FastWriter;
 class StyledWriter;
+class StyledStreamWriter;
 
 // reader.h
 class Reader;
+class CharReader;
+class CharReaderBuilder;
 
-// features.h
+// json_features.h
 class Features;
 
 // value.h
-typedef unsigned int ArrayIndex;
+using ArrayIndex = unsigned int;
 class StaticString;
 class Path;
 class PathArgument;
diff --git a/lib/jsoncpp/json/json.h b/lib/jsoncpp/json/json.h
index 625ba02e9..3f4813a95 100644
--- a/lib/jsoncpp/json/json.h
+++ b/lib/jsoncpp/json/json.h
@@ -82,17 +82,25 @@ license you like.
 // Beginning of content of file: include/json/version.h
 // //////////////////////////////////////////////////////////////////////
 
-// DO NOT EDIT. This file (and "version") is generated by CMake.
-// Run CMake configure step to update it.
 #ifndef JSON_VERSION_H_INCLUDED
-# define JSON_VERSION_H_INCLUDED
-
-# define JSONCPP_VERSION_STRING "1.8.4"
-# define JSONCPP_VERSION_MAJOR 1
-# define JSONCPP_VERSION_MINOR 8
-# define JSONCPP_VERSION_PATCH 4
-# define JSONCPP_VERSION_QUALIFIER
-# define JSONCPP_VERSION_HEXA ((JSONCPP_VERSION_MAJOR << 24) | (JSONCPP_VERSION_MINOR << 16) | (JSONCPP_VERSION_PATCH << 8))
+#define JSON_VERSION_H_INCLUDED
+
+// Note: version must be updated in three places when doing a release. This
+// annoying process ensures that amalgamate, CMake, and meson all report the
+// correct version.
+// 1. /meson.build
+// 2. /include/json/version.h
+// 3. /CMakeLists.txt
+// IMPORTANT: also update the SOVERSION!!
+
+#define JSONCPP_VERSION_STRING "1.9.4"
+#define JSONCPP_VERSION_MAJOR 1
+#define JSONCPP_VERSION_MINOR 9
+#define JSONCPP_VERSION_PATCH 3
+#define JSONCPP_VERSION_QUALIFIER
+#define JSONCPP_VERSION_HEXA                                                   \
+  ((JSONCPP_VERSION_MAJOR << 24) | (JSONCPP_VERSION_MINOR << 16) |             \
+   (JSONCPP_VERSION_PATCH << 8))
 
 #ifdef JSONCPP_USING_SECURE_MEMORY
 #undef JSONCPP_USING_SECURE_MEMORY
@@ -113,6 +121,109 @@ license you like.
 
 
 // //////////////////////////////////////////////////////////////////////
+// Beginning of content of file: include/json/allocator.h
+// //////////////////////////////////////////////////////////////////////
+
+// 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_ALLOCATOR_H_INCLUDED
+#define JSON_ALLOCATOR_H_INCLUDED
+
+#include <cstring>
+#include <memory>
+
+#pragma pack(push, 8)
+
+namespace Json {
+template <typename T> class SecureAllocator {
+public:
+  // Type definitions
+  using value_type = T;
+  using pointer = T*;
+  using const_pointer = const T*;
+  using reference = T&;
+  using const_reference = const T&;
+  using size_type = std::size_t;
+  using difference_type = std::ptrdiff_t;
+
+  /**
+   * Allocate memory for N items using the standard allocator.
+   */
+  pointer allocate(size_type n) {
+    // allocate using "global operator new"
+    return static_cast<pointer>(::operator new(n * sizeof(T)));
+  }
+
+  /**
+   * Release memory which was allocated for N items at pointer P.
+   *
+   * The memory block is filled with zeroes before being released.
+   * The pointer argument is tagged as "volatile" to prevent the
+   * compiler optimizing out this critical step.
+   */
+  void deallocate(volatile pointer p, size_type n) {
+    std::memset(p, 0, n * sizeof(T));
+    // free using "global operator delete"
+    ::operator delete(p);
+  }
+
+  /**
+   * Construct an item in-place at pointer P.
+   */
+  template <typename... Args> void construct(pointer p, Args&&... args) {
+    // construct using "placement new" and "perfect forwarding"
+    ::new (static_cast<void*>(p)) T(std::forward<Args>(args)...);
+  }
+
+  size_type max_size() const { return size_t(-1) / sizeof(T); }
+
+  pointer address(reference x) const { return std::addressof(x); }
+
+  const_pointer address(const_reference x) const { return std::addressof(x); }
+
+  /**
+   * Destroy an item in-place at pointer P.
+   */
+  void destroy(pointer p) {
+    // destroy using "explicit destructor"
+    p->~T();
+  }
+
+  // Boilerplate
+  SecureAllocator() {}
+  template <typename U> SecureAllocator(const SecureAllocator<U>&) {}
+  template <typename U> struct rebind { using other = SecureAllocator<U>; };
+};
+
+template <typename T, typename U>
+bool operator==(const SecureAllocator<T>&, const SecureAllocator<U>&) {
+  return true;
+}
+
+template <typename T, typename U>
+bool operator!=(const SecureAllocator<T>&, const SecureAllocator<U>&) {
+  return false;
+}
+
+} // namespace Json
+
+#pragma pack(pop)
+
+#endif // JSON_ALLOCATOR_H_INCLUDED
+
+// //////////////////////////////////////////////////////////////////////
+// End of content of file: include/json/allocator.h
+// //////////////////////////////////////////////////////////////////////
+
+
+
+
+
+
+// //////////////////////////////////////////////////////////////////////
 // Beginning of content of file: include/json/config.h
 // //////////////////////////////////////////////////////////////////////
 
@@ -123,19 +234,14 @@ license you like.
 
 #ifndef JSON_CONFIG_H_INCLUDED
 #define JSON_CONFIG_H_INCLUDED
-#include <stddef.h>
-#include <string> //typedef String
-#include <stdint.h> //typedef int64_t, uint64_t
-
-/// If defined, indicates that json library is embedded in CppTL library.
-//# define JSON_IN_CPPTL 1
-
-/// If defined, indicates that json may leverage CppTL library
-//#  define JSON_USE_CPPTL 1
-/// If defined, indicates that cpptl vector based map should be used instead of
-/// std::map
-/// as Value container.
-//#  define JSON_USE_CPPTL_SMALLMAP 1
+#include <cstddef>
+#include <cstdint>
+#include <istream>
+#include <memory>
+#include <ostream>
+#include <sstream>
+#include <string>
+#include <type_traits>
 
 // If non-zero, the library uses exceptions to report bad input instead of C
 // assertion macros. The default is to use exceptions.
@@ -143,164 +249,132 @@ license you like.
 #define JSON_USE_EXCEPTION 1
 #endif
 
+// Temporary, tracked for removal with issue #982.
+#ifndef JSON_USE_NULLREF
+#define JSON_USE_NULLREF 1
+#endif
+
 /// If defined, indicates that the source file is amalgamated
 /// to prevent private header inclusion.
 /// Remarks: it is automatically defined in the generated amalgamated header.
 // #define JSON_IS_AMALGAMATION
 
-#ifdef JSON_IN_CPPTL
-#include <cpptl/config.h>
-#ifndef JSON_USE_CPPTL
-#define JSON_USE_CPPTL 1
-#endif
-#endif
-
-#ifdef JSON_IN_CPPTL
-#define JSON_API CPPTL_API
-#elif defined(JSON_DLL_BUILD)
+// Export macros for DLL visibility
+#if defined(JSON_DLL_BUILD)
 #if defined(_MSC_VER) || defined(__MINGW32__)
 #define JSON_API __declspec(dllexport)
 #define JSONCPP_DISABLE_DLL_INTERFACE_WARNING
+#elif defined(__GNUC__) || defined(__clang__)
+#define JSON_API __attribute__((visibility("default")))
 #endif // if defined(_MSC_VER)
+
 #elif defined(JSON_DLL)
 #if defined(_MSC_VER) || defined(__MINGW32__)
 #define JSON_API __declspec(dllimport)
 #define JSONCPP_DISABLE_DLL_INTERFACE_WARNING
 #endif // if defined(_MSC_VER)
-#endif // ifdef JSON_IN_CPPTL
+#endif // ifdef JSON_DLL_BUILD
+
 #if !defined(JSON_API)
 #define JSON_API
 #endif
 
-// If JSON_NO_INT64 is defined, then Json only support C++ "int" type for
-// integer
-// Storages, and 64 bits integer support is disabled.
-// #define JSON_NO_INT64 1
+#if defined(_MSC_VER) && _MSC_VER < 1800
+#error                                                                         \
+    "ERROR:  Visual Studio 12 (2013) with _MSC_VER=1800 is the oldest supported compiler with sufficient C++11 capabilities"
+#endif
 
-#if defined(_MSC_VER) // MSVC
-#  if _MSC_VER <= 1200 // MSVC 6
-    // Microsoft Visual Studio 6 only support conversion from __int64 to double
-    // (no conversion from unsigned __int64).
-#    define JSON_USE_INT64_DOUBLE_CONVERSION 1
-    // Disable warning 4786 for VS6 caused by STL (identifier was truncated to '255'
-    // characters in the debug information)
-    // All projects I've ever seen with VS6 were using this globally (not bothering
-    // with pragma push/pop).
-#    pragma warning(disable : 4786)
-#  endif // MSVC 6
-
-#  if _MSC_VER >= 1500 // MSVC 2008
-    /// Indicates that the following function is deprecated.
-#    define JSONCPP_DEPRECATED(message) __declspec(deprecated(message))
-#  endif
-
-#endif // defined(_MSC_VER)
-
-// In c++11 the override keyword allows you to explicitly define that a function
-// is intended to override the base-class version.  This makes the code more
-// managable and fixes a set of common hard-to-find bugs.
-#if __cplusplus >= 201103L
-# define JSONCPP_OVERRIDE override
-# define JSONCPP_NOEXCEPT noexcept
-#elif defined(_MSC_VER) && _MSC_VER > 1600 && _MSC_VER < 1900
-# define JSONCPP_OVERRIDE override
-# define JSONCPP_NOEXCEPT throw()
-#elif defined(_MSC_VER) && _MSC_VER >= 1900
-# define JSONCPP_OVERRIDE override
-# define JSONCPP_NOEXCEPT noexcept
+#if defined(_MSC_VER) && _MSC_VER < 1900
+// As recommended at
+// https://stackoverflow.com/questions/2915672/snprintf-and-visual-studio-2010
+extern JSON_API int msvc_pre1900_c99_snprintf(char* outBuf, size_t size,
+                                              const char* format, ...);
+#define jsoncpp_snprintf msvc_pre1900_c99_snprintf
 #else
-# define JSONCPP_OVERRIDE
-# define JSONCPP_NOEXCEPT throw()
+#define jsoncpp_snprintf std::snprintf
 #endif
 
-#ifndef JSON_HAS_RVALUE_REFERENCES
+// If JSON_NO_INT64 is defined, then Json only support C++ "int" type for
+// integer
+// Storages, and 64 bits integer support is disabled.
+// #define JSON_NO_INT64 1
 
-#if defined(_MSC_VER) && _MSC_VER >= 1600 // MSVC >= 2010
-#define JSON_HAS_RVALUE_REFERENCES 1
-#endif // MSVC >= 2010
+// JSONCPP_OVERRIDE is maintained for backwards compatibility of external tools.
+// C++11 should be used directly in JSONCPP.
+#define JSONCPP_OVERRIDE override
 
 #ifdef __clang__
-#if __has_feature(cxx_rvalue_references)
-#define JSON_HAS_RVALUE_REFERENCES 1
-#endif  // has_feature
-
-#elif defined __GNUC__ // not clang (gcc comes later since clang emulates gcc)
-#if defined(__GXX_EXPERIMENTAL_CXX0X__) || (__cplusplus >= 201103L)
-#define JSON_HAS_RVALUE_REFERENCES 1
-#endif  // GXX_EXPERIMENTAL
-
-#endif // __clang__ || __GNUC__
-
-#endif // not defined JSON_HAS_RVALUE_REFERENCES
-
-#ifndef JSON_HAS_RVALUE_REFERENCES
-#define JSON_HAS_RVALUE_REFERENCES 0
+#if __has_extension(attribute_deprecated_with_message)
+#define JSONCPP_DEPRECATED(message) __attribute__((deprecated(message)))
 #endif
-
-#ifdef __clang__
-#  if __has_extension(attribute_deprecated_with_message)
-#    define JSONCPP_DEPRECATED(message)  __attribute__ ((deprecated(message)))
-#  endif
-#elif defined __GNUC__ // not clang (gcc comes later since clang emulates gcc)
-#  if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))
-#    define JSONCPP_DEPRECATED(message)  __attribute__ ((deprecated(message)))
-#  elif (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
-#    define JSONCPP_DEPRECATED(message)  __attribute__((__deprecated__))
-#  endif  // GNUC version
-#endif // __clang__ || __GNUC__
+#elif defined(__GNUC__) // not clang (gcc comes later since clang emulates gcc)
+#if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))
+#define JSONCPP_DEPRECATED(message) __attribute__((deprecated(message)))
+#elif (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
+#define JSONCPP_DEPRECATED(message) __attribute__((__deprecated__))
+#endif                  // GNUC version
+#elif defined(_MSC_VER) // MSVC (after clang because clang on Windows emulates
+                        // MSVC)
+#define JSONCPP_DEPRECATED(message) __declspec(deprecated(message))
+#endif // __clang__ || __GNUC__ || _MSC_VER
 
 #if !defined(JSONCPP_DEPRECATED)
 #define JSONCPP_DEPRECATED(message)
 #endif // if !defined(JSONCPP_DEPRECATED)
 
-#if __GNUC__ >= 6
-#  define JSON_USE_INT64_DOUBLE_CONVERSION 1
+#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 6))
+#define JSON_USE_INT64_DOUBLE_CONVERSION 1
 #endif
 
 #if !defined(JSON_IS_AMALGAMATION)
 
-# include "version.h"
-
-# if JSONCPP_USING_SECURE_MEMORY
-#  include "allocator.h" //typedef Allocator
-# endif
+#include "allocator.h"
+#include "version.h"
 
 #endif // if !defined(JSON_IS_AMALGAMATION)
 
 namespace Json {
-typedef int Int;
-typedef unsigned int UInt;
+using Int = int;
+using UInt = unsigned int;
 #if defined(JSON_NO_INT64)
-typedef int LargestInt;
-typedef unsigned int LargestUInt;
+using LargestInt = int;
+using LargestUInt = unsigned int;
 #undef JSON_HAS_INT64
 #else                 // if defined(JSON_NO_INT64)
 // For Microsoft Visual use specific types as long long is not supported
 #if defined(_MSC_VER) // Microsoft Visual Studio
-typedef __int64 Int64;
-typedef unsigned __int64 UInt64;
+using Int64 = __int64;
+using UInt64 = unsigned __int64;
 #else                 // if defined(_MSC_VER) // Other platforms, use long long
-typedef int64_t Int64;
-typedef uint64_t UInt64;
-#endif // if defined(_MSC_VER)
-typedef Int64 LargestInt;
-typedef UInt64 LargestUInt;
+using Int64 = int64_t;
+using UInt64 = uint64_t;
+#endif                // if defined(_MSC_VER)
+using LargestInt = Int64;
+using LargestUInt = UInt64;
 #define JSON_HAS_INT64
 #endif // if defined(JSON_NO_INT64)
-#if JSONCPP_USING_SECURE_MEMORY
-#define JSONCPP_STRING        std::basic_string<char, std::char_traits<char>, Json::SecureAllocator<char> >
-#define JSONCPP_OSTRINGSTREAM std::basic_ostringstream<char, std::char_traits<char>, Json::SecureAllocator<char> >
-#define JSONCPP_OSTREAM       std::basic_ostream<char, std::char_traits<char>>
-#define JSONCPP_ISTRINGSTREAM std::basic_istringstream<char, std::char_traits<char>, Json::SecureAllocator<char> >
-#define JSONCPP_ISTREAM       std::istream
-#else
-#define JSONCPP_STRING        std::string
-#define JSONCPP_OSTRINGSTREAM std::ostringstream
-#define JSONCPP_OSTREAM       std::ostream
-#define JSONCPP_ISTRINGSTREAM std::istringstream
-#define JSONCPP_ISTREAM       std::istream
-#endif // if JSONCPP_USING_SECURE_MEMORY
-} // end namespace Json
+
+template <typename T>
+using Allocator =
+    typename std::conditional<JSONCPP_USING_SECURE_MEMORY, SecureAllocator<T>,
+                              std::allocator<T>>::type;
+using String = std::basic_string<char, std::char_traits<char>, Allocator<char>>;
+using IStringStream =
+    std::basic_istringstream<String::value_type, String::traits_type,
+                             String::allocator_type>;
+using OStringStream =
+    std::basic_ostringstream<String::value_type, String::traits_type,
+                             String::allocator_type>;
+using IStream = std::istream;
+using OStream = std::ostream;
+} // namespace Json
+
+// Legacy names (formerly macros).
+using JSONCPP_STRING = Json::String;
+using JSONCPP_ISTRINGSTREAM = Json::IStringStream;
+using JSONCPP_OSTRINGSTREAM = Json::OStringStream;
+using JSONCPP_ISTREAM = Json::IStream;
+using JSONCPP_OSTREAM = Json::OStream;
 
 #endif // JSON_CONFIG_H_INCLUDED
 
@@ -332,17 +406,23 @@ typedef UInt64 LargestUInt;
 namespace Json {
 
 // writer.h
+class StreamWriter;
+class StreamWriterBuilder;
+class Writer;
 class FastWriter;
 class StyledWriter;
+class StyledStreamWriter;
 
 // reader.h
 class Reader;
+class CharReader;
+class CharReaderBuilder;
 
-// features.h
+// json_features.h
 class Features;
 
 // value.h
-typedef unsigned int ArrayIndex;
+using ArrayIndex = unsigned int;
 class StaticString;
 class Path;
 class PathArgument;
@@ -365,7 +445,7 @@ class ValueConstIterator;
 
 
 // //////////////////////////////////////////////////////////////////////
-// Beginning of content of file: include/json/features.h
+// Beginning of content of file: include/json/json_features.h
 // //////////////////////////////////////////////////////////////////////
 
 // Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
@@ -373,8 +453,8 @@ class ValueConstIterator;
 // recognized in your jurisdiction.
 // See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
 
-#ifndef CPPTL_JSON_FEATURES_H_INCLUDED
-#define CPPTL_JSON_FEATURES_H_INCLUDED
+#ifndef JSON_FEATURES_H_INCLUDED
+#define JSON_FEATURES_H_INCLUDED
 
 #if !defined(JSON_IS_AMALGAMATION)
 #include "forwards.h"
@@ -411,27 +491,27 @@ public:
   Features();
 
   /// \c true if comments are allowed. Default: \c true.
-  bool allowComments_;
+  bool allowComments_{true};
 
   /// \c true if root must be either an array or an object value. Default: \c
   /// false.
-  bool strictRoot_;
+  bool strictRoot_{false};
 
   /// \c true if dropped null placeholders are allowed. Default: \c false.
-  bool allowDroppedNullPlaceholders_;
+  bool allowDroppedNullPlaceholders_{false};
 
   /// \c true if numeric object key are allowed. Default: \c false.
-  bool allowNumericKeys_;
+  bool allowNumericKeys_{false};
 };
 
 } // namespace Json
 
 #pragma pack(pop)
 
-#endif // CPPTL_JSON_FEATURES_H_INCLUDED
+#endif // JSON_FEATURES_H_INCLUDED
 
 // //////////////////////////////////////////////////////////////////////
-// End of content of file: include/json/features.h
+// End of content of file: include/json/json_features.h
 // //////////////////////////////////////////////////////////////////////
 
 
@@ -448,38 +528,49 @@ public:
 // recognized in your jurisdiction.
 // See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
 
-#ifndef CPPTL_JSON_H_INCLUDED
-#define CPPTL_JSON_H_INCLUDED
+#ifndef JSON_H_INCLUDED
+#define JSON_H_INCLUDED
 
 #if !defined(JSON_IS_AMALGAMATION)
 #include "forwards.h"
 #endif // if !defined(JSON_IS_AMALGAMATION)
-#include <string>
-#include <vector>
-#include <exception>
 
-#ifndef JSON_USE_CPPTL_SMALLMAP
-#include <map>
+// 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
-#include <cpptl/smallmap.h>
+#define JSONCPP_NORETURN [[noreturn]]
 #endif
-#ifdef JSON_USE_CPPTL
-#include <cpptl/forwards.h>
 #endif
 
-//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)
-#    define JSONCPP_NORETURN __declspec(noreturn)
-#  elif defined(__GNUC__)
-#    define JSONCPP_NORETURN __attribute__ ((__noreturn__))
-#  else
-#    define JSONCPP_NORETURN
-#  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)
@@ -493,17 +584,19 @@ public:
  */
 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(JSONCPP_STRING const& msg);
-  ~Exception() JSONCPP_NOEXCEPT JSONCPP_OVERRIDE;
-  char const* what() const JSONCPP_NOEXCEPT JSONCPP_OVERRIDE;
+  Exception(String msg);
+  ~Exception() noexcept override;
+  char const* what() const noexcept override;
+
 protected:
-  JSONCPP_STRING msg_;
+  String msg_;
 };
 
 /** Exceptions which the user cannot easily avoid.
@@ -514,7 +607,7 @@ protected:
  */
 class JSON_API RuntimeError : public Exception {
 public:
-  RuntimeError(JSONCPP_STRING const& msg);
+  RuntimeError(String const& msg);
 };
 
 /** Exceptions thrown by JSON_ASSERT/JSON_FAIL macros.
@@ -525,13 +618,14 @@ public:
  */
 class JSON_API LogicError : public Exception {
 public:
-  LogicError(JSONCPP_STRING const& msg);
+  LogicError(String const& msg);
 };
+#endif
 
 /// used internally
-JSONCPP_NORETURN void throwRuntimeError(JSONCPP_STRING const& msg);
+JSONCPP_NORETURN void throwRuntimeError(String const& msg);
 /// used internally
-JSONCPP_NORETURN void throwLogicError(JSONCPP_STRING const& msg);
+JSONCPP_NORETURN void throwLogicError(String const& msg);
 
 /** \brief Type of the value held by a Value object.
  */
@@ -554,10 +648,12 @@ enum CommentPlacement {
   numberOfCommentPlacement
 };
 
-//# ifdef JSON_USE_CPPTL
-//   typedef CppTL::AnyEnumerator<const char *> EnumMemberNames;
-//   typedef CppTL::AnyEnumerator<const Value &> EnumValues;
-//# endif
+/** \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.
  *
@@ -610,7 +706,7 @@ private:
  * 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 a #objectValue values using
+ * 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.
@@ -621,76 +717,86 @@ private:
  */
 class JSON_API Value {
   friend class ValueIteratorBase;
+
 public:
-  typedef std::vector<JSONCPP_STRING> Members;
-  typedef ValueIterator iterator;
-  typedef ValueConstIterator const_iterator;
-  typedef Json::UInt UInt;
-  typedef Json::Int Int;
+  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)
-  typedef Json::UInt64 UInt64;
-  typedef Json::Int64 Int64;
+  using UInt64 = Json::UInt64;
+  using Int64 = Json::Int64;
 #endif // defined(JSON_HAS_INT64)
-  typedef Json::LargestInt LargestInt;
-  typedef Json::LargestUInt LargestUInt;
-  typedef Json::ArrayIndex ArrayIndex;
+  using LargestInt = Json::LargestInt;
+  using LargestUInt = Json::LargestUInt;
+  using ArrayIndex = Json::ArrayIndex;
 
   // Required for boost integration, e. g. BOOST_TEST
-  typedef std::string value_type;
+  using value_type = std::string;
+
+#if JSON_USE_NULLREF
+  // Binary compatibility kludges, do not use.
+  static const Value& null;
+  static const Value& nullRef;
+#endif
 
-  static const Value& null;  ///< We regret this reference to a global instance; prefer the simpler Value().
-  static const Value& nullRef;  ///< just a kludge for binary-compatibility; same as null
-  static Value const& nullSingleton(); ///< Prefer this to null or nullRef.
+  // 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 const LargestInt minLargestInt;
+  static constexpr LargestInt minLargestInt =
+      LargestInt(~(LargestUInt(-1) / 2));
   /// Maximum signed integer value that can be stored in a Json::Value.
-  static const LargestInt maxLargestInt;
+  static constexpr LargestInt maxLargestInt = LargestInt(LargestUInt(-1) / 2);
   /// Maximum unsigned integer value that can be stored in a Json::Value.
-  static const LargestUInt maxLargestUInt;
+  static constexpr LargestUInt maxLargestUInt = LargestUInt(-1);
 
   /// Minimum signed int value that can be stored in a Json::Value.
-  static const Int minInt;
+  static constexpr Int minInt = Int(~(UInt(-1) / 2));
   /// Maximum signed int value that can be stored in a Json::Value.
-  static const Int maxInt;
+  static constexpr Int maxInt = Int(UInt(-1) / 2);
   /// Maximum unsigned int value that can be stored in a Json::Value.
-  static const UInt maxUInt;
+  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 const Int64 minInt64;
+  static constexpr Int64 minInt64 = Int64(~(UInt64(-1) / 2));
   /// Maximum signed 64 bits int value that can be stored in a Json::Value.
-  static const Int64 maxInt64;
+  static constexpr Int64 maxInt64 = Int64(UInt64(-1) / 2);
   /// Maximum unsigned 64 bits int value that can be stored in a Json::Value.
-  static const UInt64 maxUInt64;
+  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
-    };
+    enum DuplicationPolicy { noDuplication = 0, duplicate, duplicateOnCopy };
     CZString(ArrayIndex index);
     CZString(char const* str, unsigned length, DuplicationPolicy allocate);
     CZString(CZString const& other);
-#if JSON_HAS_RVALUE_REFERENCES
     CZString(CZString&& other);
-#endif
     ~CZString();
     CZString& operator=(const CZString& other);
-
-#if JSON_HAS_RVALUE_REFERENCES
     CZString& operator=(CZString&& other);
-#endif
 
     bool operator<(CZString const& other) const;
     bool operator==(CZString const& other) const;
     ArrayIndex index() const;
-    //const char* c_str() const; ///< \deprecated
+    // const char* c_str() const; ///< \deprecated
     char const* data() const;
     unsigned length() const;
     bool isStaticString() const;
@@ -699,11 +805,11 @@ private:
     void swap(CZString& other);
 
     struct StringStorage {
-      unsigned policy_: 2;
-      unsigned length_: 30; // 1GB max
+      unsigned policy_ : 2;
+      unsigned length_ : 30; // 1GB max
     };
 
-    char const* cstr_;  // actually, a prefixed string, unless policy is noDup
+    char const* cstr_; // actually, a prefixed string, unless policy is noDup
     union {
       ArrayIndex index_;
       StringStorage storage_;
@@ -711,29 +817,26 @@ private:
   };
 
 public:
-#ifndef JSON_USE_CPPTL_SMALLMAP
   typedef std::map<CZString, Value> ObjectValues;
-#else
-  typedef CppTL::SmallMap<CZString, Value> ObjectValues;
-#endif // ifndef JSON_USE_CPPTL_SMALLMAP
 #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
-  */
+  /**
+   * \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);
@@ -744,38 +847,35 @@ Json::Value obj_value(Json::objectValue); // {}
   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.
-
+  /**
+   * \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.
+   * 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.)
+   * 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
+   *   \code
+   *   static StaticString foo("some text");
+   *   Json::Value aValue(foo);
+   *   \endcode
    */
   Value(const StaticString& value);
-  Value(const JSONCPP_STRING& value); ///< Copy data() til size(). Embedded zeroes too.
-#ifdef JSON_USE_CPPTL
-  Value(const CppTL::ConstString& value);
-#endif
+  Value(const String& value);
   Value(bool value);
-  /// Deep copy.
+  Value(std::nullptr_t ptr) = delete;
   Value(const Value& other);
-#if JSON_HAS_RVALUE_REFERENCES
-  /// Move constructor
   Value(Value&& other);
-#endif
   ~Value();
 
-  /// Deep copy, then swap(other).
-  /// \note Over-write existing comments. To preserve comments, use #swapPayload().
-  Value& operator=(Value other);
+  /// \note Overwrite existing comments. To preserve comments, use
+  /// #swapPayload().
+  Value& operator=(const Value& other);
+  Value& operator=(Value&& other);
 
   /// Swap everything.
   void swap(Value& other);
@@ -800,17 +900,14 @@ Json::Value obj_value(Json::objectValue); // {}
 
   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
+  unsigned getCStringLength() const; // Allows you to understand the length of
+                                     // the CString
 #endif
-  JSONCPP_STRING asString() const; ///< Embedded zeroes are possible.
+  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;
-#ifdef JSON_USE_CPPTL
-  CppTL::ConstString asConstString() const;
-#endif
+  bool getString(char const** begin, char const** end) const;
   Int asInt() const;
   UInt asUInt() const;
 #if defined(JSON_HAS_INT64)
@@ -836,6 +933,10 @@ Json::Value obj_value(Json::objectValue); // {}
   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
@@ -853,42 +954,33 @@ Json::Value obj_value(Json::objectValue); // {}
   /// \post type() is unchanged
   void clear();
 
-  /// Resize the array to size elements.
+  /// 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 size);
+  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.
+  //@{
+  /// 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.)
+  /// this from the operator[] which takes a string.)
   Value& operator[](ArrayIndex index);
-
-  /// 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[](int index);
+  //@}
 
-  /// Access an array element (zero based 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.)
+  /// this from the operator[] which takes a string.)
   const Value& operator[](ArrayIndex index) const;
-
-  /// 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[](int index) const;
+  //@}
 
   /// If the array contains at least index+1 elements, returns the element
-  /// value,
-  /// otherwise returns defaultValue.
+  /// value, otherwise returns defaultValue.
   Value get(ArrayIndex index, const Value& defaultValue) const;
   /// Return true if index < size().
   bool isValidIndex(ArrayIndex index) const;
@@ -896,61 +988,51 @@ Json::Value obj_value(Json::objectValue); // {}
   ///
   /// Equivalent to jsonvalue[jsonvalue.size()] = value;
   Value& append(const Value& value);
-
-#if JSON_HAS_RVALUE_REFERENCES
   Value& append(Value&& value);
-#endif
+
+  /// \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.
+  /// 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 JSONCPP_STRING& key);
+  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 JSONCPP_STRING& key) const;
+  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.
+   * 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
+   *   \code
+   *   Json::Value object;
+   *   static const StaticString code("code");
+   *   object[code] = 1234;
+   *   \endcode
    */
   Value& operator[](const StaticString& key);
-#ifdef JSON_USE_CPPTL
-  /// Access an object value by name, create a null member if it does not exist.
-  Value& operator[](const CppTL::ConstString& key);
-  /// Access an object value by name, returns null if there is no member with
-  /// that name.
-  const Value& operator[](const CppTL::ConstString& key) const;
-#endif
   /// 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;
+  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 JSONCPP_STRING& key, const Value& defaultValue) const;
-#ifdef JSON_USE_CPPTL
-  /// Return the member named key if it exist, defaultValue otherwise.
-  /// \note deep copy
-  Value get(const CppTL::ConstString& key, const Value& defaultValue) const;
-#endif
+  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
@@ -958,51 +1040,44 @@ Json::Value obj_value(Json::objectValue); // {}
   /// 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 const* demand(char const* begin, char const* end);
+  Value* demand(char const* begin, char const* end);
   /// \brief Remove and return the named member.
   ///
   /// Do nothing if it did not exist.
-  /// \return the removed Value, or null.
   /// \pre type() is objectValue or nullValue
   /// \post type() is unchanged
-  /// \deprecated
   void removeMember(const char* key);
   /// Same as removeMember(const char*)
   /// \param key may contain embedded nulls.
-  /// \deprecated
-  void removeMember(const JSONCPP_STRING& key);
+  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(JSONCPP_STRING const& key, Value* removed);
-  /// Same as removeMember(JSONCPP_STRING const& key, Value* removed)
+   *
+   *  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 iff removed (no exceptions)
-  */
-  bool removeIndex(ArrayIndex i, Value* removed);
+   *
+   *  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 JSONCPP_STRING& key) const;
-  /// Same as isMember(JSONCPP_STRING const& key)const
+  bool isMember(const String& key) const;
+  /// Same as isMember(String const& key)const
   bool isMember(const char* begin, const char* end) const;
-#ifdef JSON_USE_CPPTL
-  /// Return true if the object has a member named key.
-  bool isMember(const CppTL::ConstString& key) const;
-#endif
 
   /// \brief Return a list of the member names.
   ///
@@ -1011,23 +1086,22 @@ Json::Value obj_value(Json::objectValue); // {}
   /// \post if type() was nullValue, it remains nullValue
   Members getMemberNames() const;
 
-  //# ifdef JSON_USE_CPPTL
-  //      EnumMemberNames enumMemberNames() const;
-  //      EnumValues enumValues() const;
-  //# endif
-
   /// \deprecated Always pass len.
-  JSONCPP_DEPRECATED("Use setComment(JSONCPP_STRING const&) instead.")
-  void setComment(const char* comment, CommentPlacement placement);
+  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);
+  void setComment(const char* comment, size_t len, CommentPlacement placement) {
+    setComment(String(comment, len), placement);
+  }
   /// Comments must be //... or /* ... */
-  void setComment(const JSONCPP_STRING& comment, CommentPlacement placement);
+  void setComment(String comment, CommentPlacement placement);
   bool hasComment(CommentPlacement placement) const;
   /// Include delimiters and embedded newlines.
-  JSONCPP_STRING getComment(CommentPlacement placement) const;
+  String getComment(CommentPlacement placement) const;
 
-  JSONCPP_STRING toStyledString() const;
+  String toStyledString() const;
 
   const_iterator begin() const;
   const_iterator end() const;
@@ -1043,20 +1117,20 @@ Json::Value obj_value(Json::objectValue); // {}
   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 CommentInfo {
-    CommentInfo();
-    ~CommentInfo();
-
-    void setComment(const char* text, size_t len);
-
-    char* comment_;
-  };
-
   // struct MemberNamesTransform
   //{
   //   typedef const char *result_type;
@@ -1071,13 +1145,33 @@ private:
     LargestUInt uint_;
     double real_;
     bool bool_;
-    char* string_;  // actually ptr to unsigned, followed by str, unless !allocated_
+    char* string_; // if allocated_, ptr to { unsigned, char[] }.
     ObjectValues* map_;
   } value_;
-  ValueType type_ : 8;
-  unsigned int allocated_ : 1; // Notes: if declared as bool, bitfield is useless.
-                               // If not allocated_, string_ must be null-terminated.
-  CommentInfo* comments_;
+
+  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);
+    Comments& operator=(const Comments& that);
+    Comments& operator=(Comments&& that);
+    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.
@@ -1085,6 +1179,36 @@ private:
   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.
  */
@@ -1095,17 +1219,13 @@ public:
   PathArgument();
   PathArgument(ArrayIndex index);
   PathArgument(const char* key);
-  PathArgument(const JSONCPP_STRING& key);
+  PathArgument(String key);
 
 private:
-  enum Kind {
-    kindNone = 0,
-    kindIndex,
-    kindKey
-  };
-  JSONCPP_STRING key_;
-  ArrayIndex index_;
-  Kind kind_;
+  enum Kind { kindNone = 0, kindIndex, kindKey };
+  String key_;
+  ArrayIndex index_{};
+  Kind kind_{kindNone};
 };
 
 /** \brief Experimental and untested: represents a "path" to access a node.
@@ -1117,12 +1237,11 @@ private:
  * - ".name1.name2.name3"
  * - ".[0][1][2].name1[3]"
  * - ".%" => member name is provided as parameter
- * - ".[%]" => index is provied as parameter
+ * - ".[%]" => index is provided as parameter
  */
 class JSON_API Path {
 public:
-  Path(const JSONCPP_STRING& path,
-       const PathArgument& a1 = PathArgument(),
+  Path(const String& path, const PathArgument& a1 = PathArgument(),
        const PathArgument& a2 = PathArgument(),
        const PathArgument& a3 = PathArgument(),
        const PathArgument& a4 = PathArgument(),
@@ -1135,15 +1254,13 @@ public:
   Value& make(Value& root) const;
 
 private:
-  typedef std::vector<const PathArgument*> InArgs;
-  typedef std::vector<PathArgument> Args;
+  using InArgs = std::vector<const PathArgument*>;
+  using Args = std::vector<PathArgument>;
 
-  void makePath(const JSONCPP_STRING& path, const InArgs& in);
-  void addPathInArg(const JSONCPP_STRING& path,
-                    const InArgs& in,
-                    InArgs::const_iterator& itInArg,
-                    PathArgument::Kind kind);
-  void invalidPath(const JSONCPP_STRING& path, int location);
+  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_;
 };
@@ -1153,10 +1270,10 @@ private:
  */
 class JSON_API ValueIteratorBase {
 public:
-  typedef std::bidirectional_iterator_tag iterator_category;
-  typedef unsigned int size_t;
-  typedef int difference_type;
-  typedef ValueIteratorBase SelfType;
+  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); }
 
@@ -1170,17 +1287,19 @@ public:
   /// Value.
   Value key() const;
 
-  /// Return the index of the referenced Value, or -1 if it is not an arrayValue.
+  /// 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.
-  JSONCPP_STRING name() const;
+  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.
+  /// \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
@@ -1189,7 +1308,14 @@ public:
   char const* memberName(char const** end) const;
 
 protected:
-  Value& deref() const;
+  /*! 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();
 
@@ -1204,7 +1330,7 @@ protected:
 private:
   Value::ObjectValues::iterator current_;
   // Indicates that iterator is for a null value.
-  bool isNull_;
+  bool isNull_{true};
 
 public:
   // For some reason, BORLAND needs these at the end, rather
@@ -1220,20 +1346,21 @@ class JSON_API ValueConstIterator : public ValueIteratorBase {
   friend class Value;
 
 public:
-  typedef const Value value_type;
-  //typedef unsigned int size_t;
-  //typedef int difference_type;
-  typedef const Value& reference;
-  typedef const Value* pointer;
-  typedef ValueConstIterator SelfType;
+  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.
- */
+  /*! \internal Use by Value to create an iterator.
+   */
   explicit ValueConstIterator(const Value::ObjectValues::iterator& current);
+
 public:
   SelfType& operator=(const ValueIteratorBase& other);
 
@@ -1270,21 +1397,22 @@ class JSON_API ValueIterator : public ValueIteratorBase {
   friend class Value;
 
 public:
-  typedef Value value_type;
-  typedef unsigned int size_t;
-  typedef int difference_type;
-  typedef Value& reference;
-  typedef Value* pointer;
-  typedef ValueIterator SelfType;
+  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.
- */
+  /*! \internal Use by Value to create an iterator.
+   */
   explicit ValueIterator(const Value::ObjectValues::iterator& current);
+
 public:
   SelfType& operator=(const SelfType& other);
 
@@ -1310,19 +1438,18 @@ public:
     return *this;
   }
 
-  reference operator*() const { return deref(); }
-
-  pointer operator->() const { return &deref(); }
+  /*! 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*() { return deref(); }
+  pointer operator->() { return &deref(); }
 };
 
-} // namespace Json
-
+inline void swap(Value& a, Value& b) { a.swap(b); }
 
-namespace std {
-/// Specialize std::swap() for Json::Value.
-template<>
-inline void swap(Json::Value& a, Json::Value& b) { a.swap(b); }
-}
+} // namespace Json
 
 #pragma pack(pop)
 
@@ -1330,7 +1457,7 @@ inline void swap(Json::Value& a, Json::Value& b) { a.swap(b); }
 #pragma warning(pop)
 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 
-#endif // CPPTL_JSON_H_INCLUDED
+#endif // JSON_H_INCLUDED
 
 // //////////////////////////////////////////////////////////////////////
 // End of content of file: include/json/value.h
@@ -1350,18 +1477,18 @@ inline void swap(Json::Value& a, Json::Value& b) { a.swap(b); }
 // recognized in your jurisdiction.
 // See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
 
-#ifndef CPPTL_JSON_READER_H_INCLUDED
-#define CPPTL_JSON_READER_H_INCLUDED
+#ifndef JSON_READER_H_INCLUDED
+#define JSON_READER_H_INCLUDED
 
 #if !defined(JSON_IS_AMALGAMATION)
-#include "features.h"
+#include "json_features.h"
 #include "value.h"
 #endif // if !defined(JSON_IS_AMALGAMATION)
 #include <deque>
 #include <iosfwd>
+#include <istream>
 #include <stack>
 #include <string>
-#include <istream>
 
 // Disable warning C4251: <data member>: <type> needs to have dll-interface to
 // be used by...
@@ -1375,132 +1502,130 @@ inline void swap(Json::Value& a, Json::Value& b) { a.swap(b); }
 namespace Json {
 
 /** \brief Unserialize a <a HREF="http://www.json.org">JSON</a> document into a
- *Value.
+ * Value.
  *
  * \deprecated Use CharReader and CharReaderBuilder.
  */
-class JSONCPP_DEPRECATED("Use CharReader and CharReaderBuilder instead") JSON_API Reader {
+
+class JSONCPP_DEPRECATED(
+    "Use CharReader and CharReaderBuilder instead.") JSON_API Reader {
 public:
-  typedef char Char;
-  typedef const Char* Location;
+  using Char = char;
+  using Location = const Char*;
 
   /** \brief An error tagged with where in the JSON text it was encountered.
    *
    * The offsets give the [start, limit) range of bytes within the text. Note
    * that this is bytes, not codepoints.
-   *
    */
   struct StructuredError {
     ptrdiff_t offset_start;
     ptrdiff_t offset_limit;
-    JSONCPP_STRING message;
+    String message;
   };
 
-  /** \brief Constructs a Reader allowing all features
-   * for parsing.
+  /** \brief Constructs a Reader allowing all features for parsing.
    */
+  JSONCPP_DEPRECATED("Use CharReader and CharReaderBuilder instead")
   Reader();
 
-  /** \brief Constructs a Reader allowing the specified feature set
-   * for parsing.
+  /** \brief Constructs a Reader allowing the specified feature set for parsing.
    */
+  JSONCPP_DEPRECATED("Use CharReader and CharReaderBuilder instead")
   Reader(const Features& features);
 
   /** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
    * document.
-   * \param document UTF-8 encoded string containing the document to read.
-   * \param root [out] Contains the root value of the document if it was
-   *             successfully parsed.
-   * \param collectComments \c true to collect comment and allow writing them
-   * back during
-   *                        serialization, \c false to discard comments.
-   *                        This parameter is ignored if
-   * Features::allowComments_
-   *                        is \c false.
+   *
+   * \param      document        UTF-8 encoded string containing the document
+   *                             to read.
+   * \param[out] root            Contains the root value of the document if it
+   *                             was successfully parsed.
+   * \param      collectComments \c true to collect comment and allow writing
+   *                             them back during serialization, \c false to
+   *                             discard comments.  This parameter is ignored
+   *                             if Features::allowComments_ is \c false.
    * \return \c true if the document was successfully parsed, \c false if an
    * error occurred.
    */
-  bool
-  parse(const std::string& document, Value& root, bool collectComments = true);
+  bool parse(const std::string& document, Value& root,
+             bool collectComments = true);
 
   /** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
-   document.
-   * \param beginDoc Pointer on the beginning of the UTF-8 encoded string of the
-   document to read.
-   * \param endDoc Pointer on the end of the UTF-8 encoded string of the
-   document to read.
-   *               Must be >= beginDoc.
-   * \param root [out] Contains the root value of the document if it was
-   *             successfully parsed.
-   * \param collectComments \c true to collect comment and allow writing them
-   back during
-   *                        serialization, \c false to discard comments.
-   *                        This parameter is ignored if
-   Features::allowComments_
-   *                        is \c false.
+   * document.
+   *
+   * \param      beginDoc        Pointer on the beginning of the UTF-8 encoded
+   *                             string of the document to read.
+   * \param      endDoc          Pointer on the end of the UTF-8 encoded string
+   *                             of the document to read.  Must be >= beginDoc.
+   * \param[out] root            Contains the root value of the document if it
+   *                             was successfully parsed.
+   * \param      collectComments \c true to collect comment and allow writing
+   *                             them back during serialization, \c false to
+   *                             discard comments.  This parameter is ignored
+   *                             if Features::allowComments_ is \c false.
    * \return \c true if the document was successfully parsed, \c false if an
-   error occurred.
+   * error occurred.
    */
-  bool parse(const char* beginDoc,
-             const char* endDoc,
-             Value& root,
+  bool parse(const char* beginDoc, const char* endDoc, Value& root,
              bool collectComments = true);
 
   /// \brief Parse from input stream.
   /// \see Json::operator>>(std::istream&, Json::Value&).
-  bool parse(JSONCPP_ISTREAM& is, Value& root, bool collectComments = true);
+  bool parse(IStream& is, Value& root, bool collectComments = true);
 
   /** \brief Returns a user friendly string that list errors in the parsed
    * document.
-   * \return Formatted error message with the list of errors with their location
-   * in
-   *         the parsed document. An empty string is returned if no error
-   * occurred
-   *         during parsing.
+   *
+   * \return Formatted error message with the list of errors with their
+   * location in the parsed document. An empty string is returned if no error
+   * occurred during parsing.
    * \deprecated Use getFormattedErrorMessages() instead (typo fix).
    */
   JSONCPP_DEPRECATED("Use getFormattedErrorMessages() instead.")
-  JSONCPP_STRING getFormatedErrorMessages() const;
+  String getFormatedErrorMessages() const;
 
   /** \brief Returns a user friendly string that list errors in the parsed
    * document.
-   * \return Formatted error message with the list of errors with their location
-   * in
-   *         the parsed document. An empty string is returned if no error
-   * occurred
-   *         during parsing.
+   *
+   * \return Formatted error message with the list of errors with their
+   * location in the parsed document. An empty string is returned if no error
+   * occurred during parsing.
    */
-  JSONCPP_STRING getFormattedErrorMessages() const;
+  String getFormattedErrorMessages() const;
 
-  /** \brief Returns a vector of structured erros encounted while parsing.
+  /** \brief Returns a vector of structured errors encountered while parsing.
+   *
    * \return A (possibly empty) vector of StructuredError objects. Currently
-   *         only one error can be returned, but the caller should tolerate
-   * multiple
-   *         errors.  This can occur if the parser recovers from a non-fatal
-   *         parse error and then encounters additional errors.
+   * only one error can be returned, but the caller should tolerate multiple
+   * errors.  This can occur if the parser recovers from a non-fatal parse
+   * error and then encounters additional errors.
    */
   std::vector<StructuredError> getStructuredErrors() const;
 
   /** \brief Add a semantic error message.
-   * \param value JSON Value location associated with the error
+   *
+   * \param value   JSON Value location associated with the error
    * \param message The error message.
-   * \return \c true if the error was successfully added, \c false if the
-   * Value offset exceeds the document size.
+   * \return \c true if the error was successfully added, \c false if the Value
+   * offset exceeds the document size.
    */
-  bool pushError(const Value& value, const JSONCPP_STRING& message);
+  bool pushError(const Value& value, const String& message);
 
   /** \brief Add a semantic error message with extra context.
-   * \param value JSON Value location associated with the error
+   *
+   * \param value   JSON Value location associated with the error
    * \param message The error message.
-   * \param extra Additional JSON Value location to contextualize the error
+   * \param extra   Additional JSON Value location to contextualize the error
    * \return \c true if the error was successfully added, \c false if either
    * Value offset exceeds the document size.
    */
-  bool pushError(const Value& value, const JSONCPP_STRING& message, const Value& extra);
+  bool pushError(const Value& value, const String& message, const Value& extra);
 
   /** \brief Return whether there are any errors.
-   * \return \c true if there are no errors to report \c false if
-   * errors have occurred.
+   *
+   * \return \c true if there are no errors to report \c false if errors have
+   * occurred.
    */
   bool good() const;
 
@@ -1532,15 +1657,15 @@ private:
   class ErrorInfo {
   public:
     Token token_;
-    JSONCPP_STRING message_;
+    String message_;
     Location extra_;
   };
 
-  typedef std::deque<ErrorInfo> Errors;
+  using Errors = std::deque<ErrorInfo>;
 
   bool readToken(Token& token);
   void skipSpaces();
-  bool match(Location pattern, int patternLength);
+  bool match(const Char* pattern, int patternLength);
   bool readComment();
   bool readCStyleComment();
   bool readCppStyleComment();
@@ -1552,142 +1677,138 @@ private:
   bool decodeNumber(Token& token);
   bool decodeNumber(Token& token, Value& decoded);
   bool decodeString(Token& token);
-  bool decodeString(Token& token, JSONCPP_STRING& decoded);
+  bool decodeString(Token& token, String& decoded);
   bool decodeDouble(Token& token);
   bool decodeDouble(Token& token, Value& decoded);
-  bool decodeUnicodeCodePoint(Token& token,
-                              Location& current,
-                              Location end,
+  bool decodeUnicodeCodePoint(Token& token, Location& current, Location end,
                               unsigned int& unicode);
-  bool decodeUnicodeEscapeSequence(Token& token,
-                                   Location& current,
-                                   Location end,
-                                   unsigned int& unicode);
-  bool addError(const JSONCPP_STRING& message, Token& token, Location extra = 0);
+  bool decodeUnicodeEscapeSequence(Token& token, Location& current,
+                                   Location end, unsigned int& unicode);
+  bool addError(const String& message, Token& token, Location extra = nullptr);
   bool recoverFromError(TokenType skipUntilToken);
-  bool addErrorAndRecover(const JSONCPP_STRING& message,
-                          Token& token,
+  bool addErrorAndRecover(const String& message, Token& token,
                           TokenType skipUntilToken);
   void skipUntilSpace();
   Value& currentValue();
   Char getNextChar();
-  void
-  getLocationLineAndColumn(Location location, int& line, int& column) const;
-  JSONCPP_STRING getLocationLineAndColumn(Location location) const;
+  void getLocationLineAndColumn(Location location, int& line,
+                                int& column) const;
+  String getLocationLineAndColumn(Location location) const;
   void addComment(Location begin, Location end, CommentPlacement placement);
   void skipCommentTokens(Token& token);
 
   static bool containsNewLine(Location begin, Location end);
-  static JSONCPP_STRING normalizeEOL(Location begin, Location end);
+  static String normalizeEOL(Location begin, Location end);
 
-  typedef std::stack<Value*> Nodes;
+  using Nodes = std::stack<Value*>;
   Nodes nodes_;
   Errors errors_;
-  JSONCPP_STRING document_;
-  Location begin_;
-  Location end_;
-  Location current_;
-  Location lastValueEnd_;
-  Value* lastValue_;
-  JSONCPP_STRING commentsBefore_;
+  String document_;
+  Location begin_{};
+  Location end_{};
+  Location current_{};
+  Location lastValueEnd_{};
+  Value* lastValue_{};
+  String commentsBefore_;
   Features features_;
-  bool collectComments_;
-};  // Reader
+  bool collectComments_{};
+}; // Reader
 
 /** Interface for reading JSON from a char array.
  */
 class JSON_API CharReader {
 public:
-  virtual ~CharReader() {}
+  virtual ~CharReader() = default;
   /** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
-   document.
-   * The document must be a UTF-8 encoded string containing the document to read.
+   * document. The document must be a UTF-8 encoded string containing the
+   * document to read.
    *
-   * \param beginDoc Pointer on the beginning of the UTF-8 encoded string of the
-   document to read.
-   * \param endDoc Pointer on the end of the UTF-8 encoded string of the
-   document to read.
-   *        Must be >= beginDoc.
-   * \param root [out] Contains the root value of the document if it was
-   *             successfully parsed.
-   * \param errs [out] Formatted error messages (if not NULL)
-   *        a user friendly string that lists errors in the parsed
-   * document.
+   * \param      beginDoc Pointer on the beginning of the UTF-8 encoded string
+   *                      of the document to read.
+   * \param      endDoc   Pointer on the end of the UTF-8 encoded string of the
+   *                      document to read. Must be >= beginDoc.
+   * \param[out] root     Contains the root value of the document if it was
+   *                      successfully parsed.
+   * \param[out] errs     Formatted error messages (if not NULL) a user
+   *                      friendly string that lists errors in the parsed
+   *                      document.
    * \return \c true if the document was successfully parsed, \c false if an
-   error occurred.
+   * error occurred.
    */
-  virtual bool parse(
-      char const* beginDoc, char const* endDoc,
-      Value* root, JSONCPP_STRING* errs) = 0;
+  virtual bool parse(char const* beginDoc, char const* endDoc, Value* root,
+                     String* errs) = 0;
 
   class JSON_API Factory {
   public:
-    virtual ~Factory() {}
+    virtual ~Factory() = default;
     /** \brief Allocate a CharReader via operator new().
      * \throw std::exception if something goes wrong (e.g. invalid settings)
      */
     virtual CharReader* newCharReader() const = 0;
-  };  // Factory
-};  // CharReader
+  }; // Factory
+};   // CharReader
 
 /** \brief Build a CharReader implementation.
-
-Usage:
-\code
-  using namespace Json;
-  CharReaderBuilder builder;
-  builder["collectComments"] = false;
-  Value value;
-  JSONCPP_STRING errs;
-  bool ok = parseFromStream(builder, std::cin, &value, &errs);
-\endcode
-*/
+ *
+ * Usage:
+ *   \code
+ *   using namespace Json;
+ *   CharReaderBuilder builder;
+ *   builder["collectComments"] = false;
+ *   Value value;
+ *   String errs;
+ *   bool ok = parseFromStream(builder, std::cin, &value, &errs);
+ *   \endcode
+ */
 class JSON_API CharReaderBuilder : public CharReader::Factory {
 public:
   // Note: We use a Json::Value so that we can add data-members to this class
   // without a major version bump.
   /** Configuration of this builder.
-    These are case-sensitive.
-    Available settings (case-sensitive):
-    - `"collectComments": false or true`
-      - true to collect comment and allow writing them
-        back during serialization, false to discard comments.
-        This parameter is ignored if allowComments is false.
-    - `"allowComments": false or true`
-      - true if comments are allowed.
-    - `"strictRoot": false or true`
-      - true if root must be either an array or an object value
-    - `"allowDroppedNullPlaceholders": false or true`
-      - true if dropped null placeholders are allowed. (See StreamWriterBuilder.)
-    - `"allowNumericKeys": false or true`
-      - true if numeric object keys are allowed.
-    - `"allowSingleQuotes": false or true`
-      - true if '' are allowed for strings (both keys and values)
-    - `"stackLimit": integer`
-      - Exceeding stackLimit (recursive depth of `readValue()`) will
-        cause an exception.
-      - This is a security issue (seg-faults caused by deeply nested JSON),
-        so the default is low.
-    - `"failIfExtra": false or true`
-      - If true, `parse()` returns false when extra non-whitespace trails
-        the JSON value in the input string.
-    - `"rejectDupKeys": false or true`
-      - If true, `parse()` returns false when a key is duplicated within an object.
-    - `"allowSpecialFloats": false or true`
-      - If true, special float values (NaNs and infinities) are allowed 
-        and their values are lossfree restorable.
-
-    You can examine 'settings_` yourself
-    to see the defaults. You can also write and read them just like any
-    JSON Value.
-    \sa setDefaults()
-    */
+   * These are case-sensitive.
+   * Available settings (case-sensitive):
+   * - `"collectComments": false or true`
+   *   - true to collect comment and allow writing them back during
+   *     serialization, false to discard comments.  This parameter is ignored
+   *     if allowComments is false.
+   * - `"allowComments": false or true`
+   *   - true if comments are allowed.
+   * - `"allowTrailingCommas": false or true`
+   *   - true if trailing commas in objects and arrays are allowed.
+   * - `"strictRoot": false or true`
+   *   - true if root must be either an array or an object value
+   * - `"allowDroppedNullPlaceholders": false or true`
+   *   - true if dropped null placeholders are allowed. (See
+   *     StreamWriterBuilder.)
+   * - `"allowNumericKeys": false or true`
+   *   - true if numeric object keys are allowed.
+   * - `"allowSingleQuotes": false or true`
+   *   - true if '' are allowed for strings (both keys and values)
+   * - `"stackLimit": integer`
+   *   - Exceeding stackLimit (recursive depth of `readValue()`) will cause an
+   *     exception.
+   *   - This is a security issue (seg-faults caused by deeply nested JSON), so
+   *     the default is low.
+   * - `"failIfExtra": false or true`
+   *   - If true, `parse()` returns false when extra non-whitespace trails the
+   *     JSON value in the input string.
+   * - `"rejectDupKeys": false or true`
+   *   - If true, `parse()` returns false when a key is duplicated within an
+   *     object.
+   * - `"allowSpecialFloats": false or true`
+   *   - If true, special float values (NaNs and infinities) are allowed and
+   *     their values are lossfree restorable.
+   *
+   * You can examine 'settings_` yourself to see the defaults. You can also
+   * write and read them just like any JSON Value.
+   * \sa setDefaults()
+   */
   Json::Value settings_;
 
   CharReaderBuilder();
-  ~CharReaderBuilder() JSONCPP_OVERRIDE;
+  ~CharReaderBuilder() override;
 
-  CharReader* newCharReader() const JSONCPP_OVERRIDE;
+  CharReader* newCharReader() const override;
 
   /** \return true if 'settings' are legal and consistent;
    *   otherwise, indicate bad settings via 'invalid'.
@@ -1696,7 +1817,7 @@ public:
 
   /** A simple way to update a specific setting.
    */
-  Value& operator[](JSONCPP_STRING key);
+  Value& operator[](const String& key);
 
   /** Called by ctor, but you can use this to reset settings_.
    * \pre 'settings' != NULL (but Json::null is fine)
@@ -1713,39 +1834,37 @@ public:
 };
 
 /** Consume entire stream and use its begin/end.
-  * Someday we might have a real StreamReader, but for now this
-  * is convenient.
-  */
-bool JSON_API parseFromStream(
-    CharReader::Factory const&,
-    JSONCPP_ISTREAM&,
-    Value* root, std::string* errs);
+ * Someday we might have a real StreamReader, but for now this
+ * is convenient.
+ */
+bool JSON_API parseFromStream(CharReader::Factory const&, IStream&, Value* root,
+                              String* errs);
 
 /** \brief Read from 'sin' into 'root'.
-
- Always keep comments from the input JSON.
-
- This can be used to read a file into a particular sub-object.
- For example:
- \code
- Json::Value root;
- cin >> root["dir"]["file"];
- cout << root;
- \endcode
- Result:
- \verbatim
- {
- "dir": {
-     "file": {
-     // The input stream JSON would be nested here.
-     }
- }
- }
- \endverbatim
- \throw std::exception on parse error.
- \see Json::operator<<()
-*/
-JSON_API JSONCPP_ISTREAM& operator>>(JSONCPP_ISTREAM&, Value&);
+ *
+ * Always keep comments from the input JSON.
+ *
+ * This can be used to read a file into a particular sub-object.
+ * For example:
+ *   \code
+ *   Json::Value root;
+ *   cin >> root["dir"]["file"];
+ *   cout << root;
+ *   \endcode
+ * Result:
+ * \verbatim
+ * {
+ * "dir": {
+ *    "file": {
+ *    // The input stream JSON would be nested here.
+ *    }
+ * }
+ * }
+ * \endverbatim
+ * \throw std::exception on parse error.
+ * \see Json::operator<<()
+ */
+JSON_API IStream& operator>>(IStream&, Value&);
 
 } // namespace Json
 
@@ -1755,7 +1874,7 @@ JSON_API JSONCPP_ISTREAM& operator>>(JSONCPP_ISTREAM&, Value&);
 #pragma warning(pop)
 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 
-#endif // CPPTL_JSON_READER_H_INCLUDED
+#endif // JSON_READER_H_INCLUDED
 
 // //////////////////////////////////////////////////////////////////////
 // End of content of file: include/json/reader.h
@@ -1781,9 +1900,9 @@ JSON_API JSONCPP_ISTREAM& operator>>(JSONCPP_ISTREAM&, Value&);
 #if !defined(JSON_IS_AMALGAMATION)
 #include "value.h"
 #endif // if !defined(JSON_IS_AMALGAMATION)
-#include <vector>
-#include <string>
 #include <ostream>
+#include <string>
+#include <vector>
 
 // Disable warning C4251: <data member>: <type> needs to have dll-interface to
 // be used by...
@@ -1799,31 +1918,31 @@ namespace Json {
 class Value;
 
 /**
-
-Usage:
-\code
-  using namespace Json;
-  void writeToStdout(StreamWriter::Factory const& factory, Value const& value) {
-    std::unique_ptr<StreamWriter> const writer(
-      factory.newStreamWriter());
-    writer->write(value, &std::cout);
-    std::cout << std::endl;  // add lf and flush
-  }
-\endcode
-*/
+ *
+ * Usage:
+ *  \code
+ *  using namespace Json;
+ *  void writeToStdout(StreamWriter::Factory const& factory, Value const& value)
+ * { std::unique_ptr<StreamWriter> const writer( factory.newStreamWriter());
+ *    writer->write(value, &std::cout);
+ *    std::cout << std::endl;  // add lf and flush
+ *  }
+ *  \endcode
+ */
 class JSON_API StreamWriter {
 protected:
-  JSONCPP_OSTREAM* sout_;  // not owned; will not delete
+  OStream* sout_; // not owned; will not delete
 public:
   StreamWriter();
   virtual ~StreamWriter();
   /** Write Value into document as configured in sub-class.
-      Do not take ownership of sout, but maintain a reference during function.
-      \pre sout != NULL
-      \return zero on success (For now, we always return zero, so check the stream instead.)
-      \throw std::exception possibly, depending on configuration
+   *   Do not take ownership of sout, but maintain a reference during function.
+   *   \pre sout != NULL
+   *   \return zero on success (For now, we always return zero, so check the
+   *   stream instead.) \throw std::exception possibly, depending on
+   * configuration
    */
-  virtual int write(Value const& root, JSONCPP_OSTREAM* sout) = 0;
+  virtual int write(Value const& root, OStream* sout) = 0;
 
   /** \brief A simple abstract factory.
    */
@@ -1834,64 +1953,69 @@ public:
      * \throw std::exception if something goes wrong (e.g. invalid settings)
      */
     virtual StreamWriter* newStreamWriter() const = 0;
-  };  // Factory
-};  // StreamWriter
+  }; // Factory
+};   // StreamWriter
 
 /** \brief Write into stringstream, then return string, for convenience.
  * A StreamWriter will be created from the factory, used, and then deleted.
  */
-JSONCPP_STRING JSON_API writeString(StreamWriter::Factory const& factory, Value const& root);
-
+String JSON_API writeString(StreamWriter::Factory const& factory,
+                            Value const& root);
 
 /** \brief Build a StreamWriter implementation.
 
-Usage:
-\code
-  using namespace Json;
-  Value value = ...;
-  StreamWriterBuilder builder;
-  builder["commentStyle"] = "None";
-  builder["indentation"] = "   ";  // or whatever you like
-  std::unique_ptr<Json::StreamWriter> writer(
-      builder.newStreamWriter());
-  writer->write(value, &std::cout);
-  std::cout << std::endl;  // add lf and flush
-\endcode
+* Usage:
+*   \code
+*   using namespace Json;
+*   Value value = ...;
+*   StreamWriterBuilder builder;
+*   builder["commentStyle"] = "None";
+*   builder["indentation"] = "   ";  // or whatever you like
+*   std::unique_ptr<Json::StreamWriter> writer(
+*      builder.newStreamWriter());
+*   writer->write(value, &std::cout);
+*   std::cout << std::endl;  // add lf and flush
+*   \endcode
 */
 class JSON_API StreamWriterBuilder : public StreamWriter::Factory {
 public:
   // Note: We use a Json::Value so that we can add data-members to this class
   // without a major version bump.
   /** Configuration of this builder.
-    Available settings (case-sensitive):
-    - "commentStyle": "None" or "All"
-    - "indentation":  "<anything>"
-    - "enableYAMLCompatibility": false or true
-      - slightly change the whitespace around colons
-    - "dropNullPlaceholders": false or true
-      - Drop the "null" string from the writer's output for nullValues.
-        Strictly speaking, this is not valid JSON. But when the output is being
-        fed to a browser's JavaScript, it makes for smaller output and the
-        browser can handle the output just fine.
-    - "useSpecialFloats": false or true
-      - If true, outputs non-finite floating point values in the following way:
-        NaN values as "NaN", positive infinity as "Infinity", and negative infinity
-        as "-Infinity".
-
-    You can examine 'settings_` yourself
-    to see the defaults. You can also write and read them just like any
-    JSON Value.
-    \sa setDefaults()
-    */
+   *  Available settings (case-sensitive):
+   *  - "commentStyle": "None" or "All"
+   *  - "indentation":  "<anything>".
+   *  - Setting this to an empty string also omits newline characters.
+   *  - "enableYAMLCompatibility": false or true
+   *  - slightly change the whitespace around colons
+   *  - "dropNullPlaceholders": false or true
+   *  - Drop the "null" string from the writer's output for nullValues.
+   *    Strictly speaking, this is not valid JSON. But when the output is being
+   *    fed to a browser's JavaScript, it makes for smaller output and the
+   *    browser can handle the output just fine.
+   *  - "useSpecialFloats": false or true
+   *  - If true, outputs non-finite floating point values in the following way:
+   *    NaN values as "NaN", positive infinity as "Infinity", and negative
+   *  infinity as "-Infinity".
+   *  - "precision": int
+   *  - Number of precision digits for formatting of real values.
+   *  - "precisionType": "significant"(default) or "decimal"
+   *  - Type of precision for formatting of real values.
+
+   *  You can examine 'settings_` yourself
+   *  to see the defaults. You can also write and read them just like any
+   *  JSON Value.
+   *  \sa setDefaults()
+   */
   Json::Value settings_;
 
   StreamWriterBuilder();
-  ~StreamWriterBuilder() JSONCPP_OVERRIDE;
+  ~StreamWriterBuilder() override;
 
   /**
    * \throw std::exception if something goes wrong (e.g. invalid settings)
    */
-  StreamWriter* newStreamWriter() const JSONCPP_OVERRIDE;
+  StreamWriter* newStreamWriter() const override;
 
   /** \return true if 'settings' are legal and consistent;
    *   otherwise, indicate bad settings via 'invalid'.
@@ -1899,7 +2023,7 @@ public:
   bool validate(Json::Value* invalid) const;
   /** A simple way to update a specific setting.
    */
-  Value& operator[](JSONCPP_STRING key);
+  Value& operator[](const String& key);
 
   /** Called by ctor, but you can use this to reset settings_.
    * \pre 'settings' != NULL (but Json::null is fine)
@@ -1916,7 +2040,7 @@ class JSONCPP_DEPRECATED("Use StreamWriter instead") JSON_API Writer {
 public:
   virtual ~Writer();
 
-  virtual JSONCPP_STRING write(const Value& root) = 0;
+  virtual String write(const Value& root) = 0;
 };
 
 /** \brief Outputs a Value in <a HREF="http://www.json.org">JSON</a> format
@@ -1924,18 +2048,19 @@ public:
  *
  * The JSON document is written in a single line. It is not intended for 'human'
  *consumption,
- * but may be usefull to support feature such as RPC where bandwith is limited.
+ * but may be useful to support feature such as RPC where bandwidth is limited.
  * \sa Reader, Value
  * \deprecated Use StreamWriterBuilder.
  */
 #if defined(_MSC_VER)
 #pragma warning(push)
-#pragma warning(disable:4996) // Deriving from deprecated class
+#pragma warning(disable : 4996) // Deriving from deprecated class
 #endif
-class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API FastWriter : public Writer {
+class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API FastWriter
+    : public Writer {
 public:
   FastWriter();
-  ~FastWriter() JSONCPP_OVERRIDE {}
+  ~FastWriter() override = default;
 
   void enableYAMLCompatibility();
 
@@ -1949,15 +2074,15 @@ public:
   void omitEndingLineFeed();
 
 public: // overridden from Writer
-  JSONCPP_STRING write(const Value& root) JSONCPP_OVERRIDE;
+  String write(const Value& root) override;
 
 private:
   void writeValue(const Value& value);
 
-  JSONCPP_STRING document_;
-  bool yamlCompatibilityEnabled_;
-  bool dropNullPlaceholders_;
-  bool omitEndingLineFeed_;
+  String document_;
+  bool yamlCompatibilityEnabled_{false};
+  bool dropNullPlaceholders_{false};
+  bool omitEndingLineFeed_{false};
 };
 #if defined(_MSC_VER)
 #pragma warning(pop)
@@ -1989,42 +2114,43 @@ private:
  */
 #if defined(_MSC_VER)
 #pragma warning(push)
-#pragma warning(disable:4996) // Deriving from deprecated class
+#pragma warning(disable : 4996) // Deriving from deprecated class
 #endif
-class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API StyledWriter : public Writer {
+class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API
+    StyledWriter : public Writer {
 public:
   StyledWriter();
-  ~StyledWriter() JSONCPP_OVERRIDE {}
+  ~StyledWriter() override = default;
 
 public: // overridden from Writer
   /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
    * \param root Value to serialize.
    * \return String containing the JSON document that represents the root value.
    */
-  JSONCPP_STRING write(const Value& root) JSONCPP_OVERRIDE;
+  String write(const Value& root) override;
 
 private:
   void writeValue(const Value& value);
   void writeArrayValue(const Value& value);
   bool isMultilineArray(const Value& value);
-  void pushValue(const JSONCPP_STRING& value);
+  void pushValue(const String& value);
   void writeIndent();
-  void writeWithIndent(const JSONCPP_STRING& value);
+  void writeWithIndent(const String& value);
   void indent();
   void unindent();
   void writeCommentBeforeValue(const Value& root);
   void writeCommentAfterValueOnSameLine(const Value& root);
-  bool hasCommentForValue(const Value& value);
-  static JSONCPP_STRING normalizeEOL(const JSONCPP_STRING& text);
+  static bool hasCommentForValue(const Value& value);
+  static String normalizeEOL(const String& text);
 
-  typedef std::vector<JSONCPP_STRING> ChildValues;
+  using ChildValues = std::vector<String>;
 
   ChildValues childValues_;
-  JSONCPP_STRING document_;
-  JSONCPP_STRING indentString_;
-  unsigned int rightMargin_;
-  unsigned int indentSize_;
-  bool addChildValues_;
+  String document_;
+  String indentString_;
+  unsigned int rightMargin_{74};
+  unsigned int indentSize_{3};
+  bool addChildValues_{false};
 };
 #if defined(_MSC_VER)
 #pragma warning(pop)
@@ -2057,15 +2183,16 @@ private:
  */
 #if defined(_MSC_VER)
 #pragma warning(push)
-#pragma warning(disable:4996) // Deriving from deprecated class
+#pragma warning(disable : 4996) // Deriving from deprecated class
 #endif
-class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API StyledStreamWriter {
+class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API
+    StyledStreamWriter {
 public:
-/**
- * \param indentation Each level will be indented by this amount extra.
- */
-  StyledStreamWriter(JSONCPP_STRING indentation = "\t");
-  ~StyledStreamWriter() {}
+  /**
+   * \param indentation Each level will be indented by this amount extra.
+   */
+  StyledStreamWriter(String indentation = "\t");
+  ~StyledStreamWriter() = default;
 
 public:
   /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
@@ -2074,29 +2201,29 @@ public:
    * \note There is no point in deriving from Writer, since write() should not
    * return a value.
    */
-  void write(JSONCPP_OSTREAM& out, const Value& root);
+  void write(OStream& out, const Value& root);
 
 private:
   void writeValue(const Value& value);
   void writeArrayValue(const Value& value);
   bool isMultilineArray(const Value& value);
-  void pushValue(const JSONCPP_STRING& value);
+  void pushValue(const String& value);
   void writeIndent();
-  void writeWithIndent(const JSONCPP_STRING& value);
+  void writeWithIndent(const String& value);
   void indent();
   void unindent();
   void writeCommentBeforeValue(const Value& root);
   void writeCommentAfterValueOnSameLine(const Value& root);
-  bool hasCommentForValue(const Value& value);
-  static JSONCPP_STRING normalizeEOL(const JSONCPP_STRING& text);
+  static bool hasCommentForValue(const Value& value);
+  static String normalizeEOL(const String& text);
 
-  typedef std::vector<JSONCPP_STRING> ChildValues;
+  using ChildValues = std::vector<String>;
 
   ChildValues childValues_;
-  JSONCPP_OSTREAM* document_;
-  JSONCPP_STRING indentString_;
-  unsigned int rightMargin_;
-  JSONCPP_STRING indentation_;
+  OStream* document_;
+  String indentString_;
+  unsigned int rightMargin_{74};
+  String indentation_;
   bool addChildValues_ : 1;
   bool indented_ : 1;
 };
@@ -2105,18 +2232,20 @@ private:
 #endif
 
 #if defined(JSON_HAS_INT64)
-JSONCPP_STRING JSON_API valueToString(Int value);
-JSONCPP_STRING JSON_API valueToString(UInt value);
+String JSON_API valueToString(Int value);
+String JSON_API valueToString(UInt value);
 #endif // if defined(JSON_HAS_INT64)
-JSONCPP_STRING JSON_API valueToString(LargestInt value);
-JSONCPP_STRING JSON_API valueToString(LargestUInt value);
-JSONCPP_STRING JSON_API valueToString(double value);
-JSONCPP_STRING JSON_API valueToString(bool value);
-JSONCPP_STRING JSON_API valueToQuotedString(const char* value);
+String JSON_API valueToString(LargestInt value);
+String JSON_API valueToString(LargestUInt value);
+String JSON_API valueToString(
+    double value, unsigned int precision = Value::defaultRealPrecision,
+    PrecisionType precisionType = PrecisionType::significantDigits);
+String JSON_API valueToString(bool value);
+String JSON_API valueToQuotedString(const char* value);
 
 /// \brief Output using the StyledStreamWriter.
 /// \see Json::operator>>()
-JSON_API JSONCPP_OSTREAM& operator<<(JSONCPP_OSTREAM&, const Value& root);
+JSON_API OStream& operator<<(OStream&, const Value& root);
 
 } // namespace Json
 
@@ -2146,10 +2275,10 @@ JSON_API JSONCPP_OSTREAM& operator<<(JSONCPP_OSTREAM&, const Value& root);
 // recognized in your jurisdiction.
 // See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
 
-#ifndef CPPTL_JSON_ASSERTIONS_H_INCLUDED
-#define CPPTL_JSON_ASSERTIONS_H_INCLUDED
+#ifndef JSON_ASSERTIONS_H_INCLUDED
+#define JSON_ASSERTIONS_H_INCLUDED
 
-#include <stdlib.h>
+#include <cstdlib>
 #include <sstream>
 
 #if !defined(JSON_IS_AMALGAMATION)
@@ -2163,38 +2292,45 @@ JSON_API JSONCPP_OSTREAM& operator<<(JSONCPP_OSTREAM&, const Value& root);
 #if JSON_USE_EXCEPTION
 
 // @todo <= add detail about condition in exception
-# define JSON_ASSERT(condition)                                                \
-  {if (!(condition)) {Json::throwLogicError( "assert json failed" );}}
-
-# define JSON_FAIL_MESSAGE(message)                                            \
-  {                                                                            \
-    JSONCPP_OSTRINGSTREAM oss; oss << message;                                    \
+#define JSON_ASSERT(condition)                                                 \
+  do {                                                                         \
+    if (!(condition)) {                                                        \
+      Json::throwLogicError("assert json failed");                             \
+    }                                                                          \
+  } while (0)
+
+#define JSON_FAIL_MESSAGE(message)                                             \
+  do {                                                                         \
+    OStringStream oss;                                                         \
+    oss << message;                                                            \
     Json::throwLogicError(oss.str());                                          \
     abort();                                                                   \
-  }
+  } while (0)
 
 #else // JSON_USE_EXCEPTION
 
-# define JSON_ASSERT(condition) assert(condition)
+#define JSON_ASSERT(condition) assert(condition)
 
 // The call to assert() will show the failure message in debug builds. In
 // release builds we abort, for a core-dump or debugger.
-# define JSON_FAIL_MESSAGE(message)                                            \
+#define JSON_FAIL_MESSAGE(message)                                             \
   {                                                                            \
-    JSONCPP_OSTRINGSTREAM oss; oss << message;                                    \
+    OStringStream oss;                                                         \
+    oss << message;                                                            \
     assert(false && oss.str().c_str());                                        \
     abort();                                                                   \
   }
 
-
 #endif
 
 #define JSON_ASSERT_MESSAGE(condition, message)                                \
-  if (!(condition)) {                                                          \
-    JSON_FAIL_MESSAGE(message);                                                \
-  }
+  do {                                                                         \
+    if (!(condition)) {                                                        \
+      JSON_FAIL_MESSAGE(message);                                              \
+    }                                                                          \
+  } while (0)
 
-#endif // CPPTL_JSON_ASSERTIONS_H_INCLUDED
+#endif // JSON_ASSERTIONS_H_INCLUDED
 
 // //////////////////////////////////////////////////////////////////////
 // End of content of file: include/json/assertions.h