Upgrade jsoncpp to 1.9.4

Bug: 170642246
Change-Id: Id1fae5a1b6421117f923c616718ee4b3571231e0
diff --git a/include/json/allocator.h b/include/json/allocator.h
new file mode 100644
index 0000000..0f5c224
--- /dev/null
+++ b/include/json/allocator.h
@@ -0,0 +1,89 @@
+// 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
diff --git a/include/json/assertions.h b/include/json/assertions.h
index 5ef7e7b..666fa7f 100644
--- a/include/json/assertions.h
+++ b/include/json/assertions.h
@@ -1,41 +1,61 @@
-// Copyright 2007-2010 Baptiste Lepilleur
+// 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 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)
 #include "config.h"
 #endif // if !defined(JSON_IS_AMALGAMATION)
 
+/** It should not be possible for a maliciously designed file to
+ *  cause an abort() or seg-fault, so these macros are used only
+ *  for pre-condition violations and internal logic errors.
+ */
 #if JSON_USE_EXCEPTION
-#include <stdexcept>
+
+// @todo <= add detail about condition in exception
 #define JSON_ASSERT(condition)                                                 \
-  assert(condition); // @todo <= change this into an exception throw
-#define JSON_FAIL_MESSAGE(message) throw std::runtime_error(message);
+  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 bugs we write to invalid memory in order to crash hard, so that a
-// debugger or crash reporter gets the chance to take over. We still call exit()
-// afterward in order to tell the compiler that this macro doesn't return.
+// release builds we abort, for a core-dump or debugger.
 #define JSON_FAIL_MESSAGE(message)                                             \
   {                                                                            \
-    assert(false&& message);                                                   \
-    strcpy(reinterpret_cast<char*>(666), message);                             \
-    exit(123);                                                                 \
+    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
diff --git a/include/json/autolink.h b/include/json/autolink.h
deleted file mode 100644
index 6fcc8af..0000000
--- a/include/json/autolink.h
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2007-2010 Baptiste Lepilleur
-// 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_AUTOLINK_H_INCLUDED
-#define JSON_AUTOLINK_H_INCLUDED
-
-#include "config.h"
-
-#ifdef JSON_IN_CPPTL
-#include <cpptl/cpptl_autolink.h>
-#endif
-
-#if !defined(JSON_NO_AUTOLINK) && !defined(JSON_DLL_BUILD) &&                  \
-    !defined(JSON_IN_CPPTL)
-#define CPPTL_AUTOLINK_NAME "json"
-#undef CPPTL_AUTOLINK_DLL
-#ifdef JSON_DLL
-#define CPPTL_AUTOLINK_DLL
-#endif
-#include "autolink.h"
-#endif
-
-#endif // JSON_AUTOLINK_H_INCLUDED
diff --git a/include/json/config.h b/include/json/config.h
index afd3a45..6359273 100644
--- a/include/json/config.h
+++ b/include/json/config.h
@@ -1,31 +1,18 @@
-// Copyright 2007-2010 Baptiste Lepilleur
+// 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_CONFIG_H_INCLUDED
 #define JSON_CONFIG_H_INCLUDED
-
-/// 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
-/// If defined, indicates that Json specific container should be used
-/// (hash table & simple deque container with customizable allocator).
-/// THIS FEATURE IS STILL EXPERIMENTAL! There is know bugs: See #3177332
-//#  define JSON_VALUE_USE_INTERNAL_MAP 1
-/// Force usage of standard new/malloc based allocator instead of memory pool
-/// based allocator.
-/// The memory pools allocator used optimization (initializing Value and
-/// ValueInternalLink
-/// as if it was a POD) that may cause some validation tool to report errors.
-/// Only has effects if JSON_VALUE_USE_INTERNAL_MAP is defined.
-//#  define JSON_USE_SIMPLE_INTERNAL_ALLOCATOR 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.
@@ -33,80 +20,131 @@
 #define JSON_USE_EXCEPTION 1
 #endif
 
-/// If defined, indicates that the source file is amalgated
+// 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 amalgated header.
+/// 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)
-#if defined(_MSC_VER)
+// 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)
+#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 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) && _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_snprintf std::snprintf
+#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 <= 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 // if defined(_MSC_VER)  &&  _MSC_VER < 1200 // MSVC 6
+// JSONCPP_OVERRIDE is maintained for backwards compatibility of external tools.
+// C++11 should be used directly in JSONCPP.
+#define JSONCPP_OVERRIDE override
 
-#if defined(_MSC_VER) && _MSC_VER >= 1500 // MSVC 2008
-/// Indicates that the following function is deprecated.
-#define JSONCPP_DEPRECATED(message) __declspec(deprecated(message))
+#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
+#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 defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 6))
+#define JSON_USE_INT64_DOUBLE_CONVERSION 1
+#endif
+
+#if !defined(JSON_IS_AMALGAMATION)
+
+#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 long long int Int64;
-typedef unsigned long long int 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)
-} // 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
diff --git a/include/json/forwards.h b/include/json/forwards.h
index 84a26cd..affe33a 100644
--- a/include/json/forwards.h
+++ b/include/json/forwards.h
@@ -1,4 +1,4 @@
-// Copyright 2007-2010 Baptiste Lepilleur
+// 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
@@ -13,17 +13,23 @@
 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;
@@ -31,12 +37,6 @@
 class ValueIteratorBase;
 class ValueIterator;
 class ValueConstIterator;
-#ifdef JSON_VALUE_USE_INTERNAL_MAP
-class ValueMapAllocator;
-class ValueInternalLink;
-class ValueInternalArray;
-class ValueInternalMap;
-#endif // #ifdef JSON_VALUE_USE_INTERNAL_MAP
 
 } // namespace Json
 
diff --git a/include/json/json.h b/include/json/json.h
index 8f10ac2..5c776a1 100644
--- a/include/json/json.h
+++ b/include/json/json.h
@@ -1,4 +1,4 @@
-// Copyright 2007-2010 Baptiste Lepilleur
+// 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
@@ -6,10 +6,10 @@
 #ifndef JSON_JSON_H_INCLUDED
 #define JSON_JSON_H_INCLUDED
 
-#include "autolink.h"
-#include "value.h"
+#include "config.h"
+#include "json_features.h"
 #include "reader.h"
+#include "value.h"
 #include "writer.h"
-#include "features.h"
 
 #endif // JSON_JSON_H_INCLUDED
diff --git a/include/json/features.h b/include/json/json_features.h
similarity index 80%
rename from include/json/features.h
rename to include/json/json_features.h
index 1bb7bb6..7c7e9f5 100644
--- a/include/json/features.h
+++ b/include/json/json_features.h
@@ -1,15 +1,17 @@
-// Copyright 2007-2010 Baptiste Lepilleur
+// 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 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"
 #endif // if !defined(JSON_IS_AMALGAMATION)
 
+#pragma pack(push, 8)
+
 namespace Json {
 
 /** \brief Configuration passed to reader and writer.
@@ -39,19 +41,21 @@
   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
 
-#endif // CPPTL_JSON_FEATURES_H_INCLUDED
+#pragma pack(pop)
+
+#endif // JSON_FEATURES_H_INCLUDED
diff --git a/include/json/reader.h b/include/json/reader.h
index 98814d5..9175466 100644
--- a/include/json/reader.h
+++ b/include/json/reader.h
@@ -1,17 +1,18 @@
-// Copyright 2007-2010 Baptiste Lepilleur
+// 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 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>
 
@@ -22,134 +23,135 @@
 #pragma warning(disable : 4251)
 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 
+#pragma pack(push, 8)
+
 namespace Json {
 
 /** \brief Unserialize a <a HREF="http://www.json.org">JSON</a> document into a
- *Value.
+ * Value.
  *
+ * \deprecated Use CharReader and CharReaderBuilder.
  */
-class 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 {
-    size_t offset_start;
-    size_t offset_limit;
-    std::string message;
+    ptrdiff_t offset_start;
+    ptrdiff_t offset_limit;
+    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(std::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")
-  std::string getFormatedErrorMessages() const;
+  JSONCPP_DEPRECATED("Use getFormattedErrorMessages() instead.")
+  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.
    */
-  std::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 std::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 std::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;
 
@@ -181,16 +183,15 @@
   class ErrorInfo {
   public:
     Token token_;
-    std::string message_;
+    String message_;
     Location extra_;
   };
 
-  typedef std::deque<ErrorInfo> Errors;
+  using Errors = std::deque<ErrorInfo>;
 
-  bool expectToken(TokenType type, Token& token, const char* message);
   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();
@@ -202,75 +203,201 @@
   bool decodeNumber(Token& token);
   bool decodeNumber(Token& token, Value& decoded);
   bool decodeString(Token& token);
-  bool decodeString(Token& token, std::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 std::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 std::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;
-  std::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);
 
-  typedef std::stack<Value*> Nodes;
+  static bool containsNewLine(Location begin, Location end);
+  static String normalizeEOL(Location begin, Location end);
+
+  using Nodes = std::stack<Value*>;
   Nodes nodes_;
   Errors errors_;
-  std::string document_;
-  Location begin_;
-  Location end_;
-  Location current_;
-  Location lastValueEnd_;
-  Value* lastValue_;
-  std::string commentsBefore_;
+  String document_;
+  Location begin_{};
+  Location end_{};
+  Location current_{};
+  Location lastValueEnd_{};
+  Value* lastValue_{};
+  String commentsBefore_;
   Features features_;
-  bool collectComments_;
+  bool collectComments_{};
+}; // Reader
+
+/** Interface for reading JSON from a char array.
+ */
+class JSON_API CharReader {
+public:
+  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.
+   *
+   * \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.
+   */
+  virtual bool parse(char const* beginDoc, char const* endDoc, Value* root,
+                     String* errs) = 0;
+
+  class JSON_API Factory {
+  public:
+    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
+
+/** \brief Build a CharReader implementation.
+ *
+ * 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.
+   * - `"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() override;
+
+  CharReader* newCharReader() const override;
+
+  /** \return true if 'settings' are legal and consistent;
+   *   otherwise, indicate bad settings via 'invalid'.
+   */
+  bool validate(Json::Value* invalid) const;
+
+  /** A simple way to update a specific setting.
+   */
+  Value& operator[](const String& key);
+
+  /** Called by ctor, but you can use this to reset settings_.
+   * \pre 'settings' != NULL (but Json::null is fine)
+   * \remark Defaults:
+   * \snippet src/lib_json/json_reader.cpp CharReaderBuilderDefaults
+   */
+  static void setDefaults(Json::Value* settings);
+  /** Same as old Features::strictMode().
+   * \pre 'settings' != NULL (but Json::null is fine)
+   * \remark Defaults:
+   * \snippet src/lib_json/json_reader.cpp CharReaderBuilderStrictMode
+   */
+  static void strictMode(Json::Value* settings);
 };
 
+/** 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&, 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 std::istream& operator>>(std::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
 
+#pragma pack(pop)
+
 #if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 #pragma warning(pop)
 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 
-#endif // CPPTL_JSON_READER_H_INCLUDED
+#endif // JSON_READER_H_INCLUDED
diff --git a/include/json/value.h b/include/json/value.h
index 197a856..df1eba6 100644
--- a/include/json/value.h
+++ b/include/json/value.h
@@ -1,26 +1,51 @@
-// Copyright 2007-2010 Baptiste Lepilleur
+// 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 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)
+
+// Conditional NORETURN attribute on the throw functions would:
+// a) suppress false positives from static code analysis
+// b) possibly improve optimization opportunities.
+#if !defined(JSONCPP_NORETURN)
+#if defined(_MSC_VER) && _MSC_VER == 1800
+#define JSONCPP_NORETURN __declspec(noreturn)
+#else
+#define JSONCPP_NORETURN [[noreturn]]
+#endif
+#endif
+
+// Support for '= delete' with template declarations was a late addition
+// to the c++11 standard and is rejected by clang 3.8 and Apple clang 8.2
+// even though these declare themselves to be c++11 compilers.
+#if !defined(JSONCPP_TEMPLATE_DELETE)
+#if defined(__clang__) && defined(__apple_build_version__)
+#if __apple_build_version__ <= 8000042
+#define JSONCPP_TEMPLATE_DELETE
+#endif
+#elif defined(__clang__)
+#if __clang_major__ == 3 && __clang_minor__ <= 8
+#define JSONCPP_TEMPLATE_DELETE
+#endif
+#endif
+#if !defined(JSONCPP_TEMPLATE_DELETE)
+#define JSONCPP_TEMPLATE_DELETE = delete
+#endif
+#endif
+
+#include <array>
+#include <exception>
+#include <map>
+#include <memory>
 #include <string>
 #include <vector>
 
-#ifndef JSON_USE_CPPTL_SMALLMAP
-#include <map>
-#else
-#include <cpptl/smallmap.h>
-#endif
-#ifdef JSON_USE_CPPTL
-#include <cpptl/forwards.h>
-#endif
-
 // Disable warning C4251: <data member>: <type> needs to have dll-interface to
 // be used by...
 #if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
@@ -28,10 +53,55 @@
 #pragma warning(disable : 4251)
 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 
+#pragma pack(push, 8)
+
 /** \brief JSON (JavaScript Object Notation).
  */
 namespace Json {
 
+#if JSON_USE_EXCEPTION
+/** Base class for all exceptions we throw.
+ *
+ * We use nothing but these internally. Of course, STL can throw others.
+ */
+class JSON_API Exception : public std::exception {
+public:
+  Exception(String msg);
+  ~Exception() noexcept override;
+  char const* what() const noexcept override;
+
+protected:
+  String msg_;
+};
+
+/** Exceptions which the user cannot easily avoid.
+ *
+ * E.g. out-of-memory (when we use malloc), stack-overflow, malicious input
+ *
+ * \remark derived from Json::Exception
+ */
+class JSON_API RuntimeError : public Exception {
+public:
+  RuntimeError(String const& msg);
+};
+
+/** Exceptions thrown by JSON_ASSERT/JSON_FAIL macros.
+ *
+ * These are precondition-violations (user bugs) and internal errors (our bugs).
+ *
+ * \remark derived from Json::Exception
+ */
+class JSON_API LogicError : public Exception {
+public:
+  LogicError(String const& msg);
+};
+#endif
+
+/// used internally
+JSONCPP_NORETURN void throwRuntimeError(String const& msg);
+/// used internally
+JSONCPP_NORETURN void throwLogicError(String const& msg);
+
 /** \brief Type of the value held by a Value object.
  */
 enum ValueType {
@@ -53,14 +123,16 @@
   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.
  *
- * Value constructor and objectValue member assignement takes advantage of the
+ * Value constructor and objectValue member assignment takes advantage of the
  * StaticString and avoid the cost of string duplication when storing the
  * string or the member name.
  *
@@ -74,14 +146,14 @@
  */
 class JSON_API StaticString {
 public:
-  explicit StaticString(const char* czstring) : str_(czstring) {}
+  explicit StaticString(const char* czstring) : c_str_(czstring) {}
 
-  operator const char*() const { return str_; }
+  operator const char*() const { return c_str_; }
 
-  const char* c_str() const { return str_; }
+  const char* c_str() const { return c_str_; }
 
 private:
-  const char* str_;
+  const char* c_str_;
 };
 
 /** \brief Represents a <a HREF="http://www.json.org">JSON</a> value.
@@ -99,116 +171,147 @@
  * The type of the held value is represented by a #ValueType and
  * can be obtained using type().
  *
- * values of an #objectValue or #arrayValue can be accessed using operator[]()
- *methods.
- * Non const methods will automatically create the a #nullValue element
+ * Values of an #objectValue or #arrayValue can be accessed using operator[]()
+ * methods.
+ * Non-const methods will automatically create the a #nullValue element
  * if it does not exist.
- * The sequence of an #arrayValue will be automatically resize and initialized
+ * The sequence of an #arrayValue will be automatically resized and initialized
  * with #nullValue. resize() can be used to enlarge or truncate an #arrayValue.
  *
- * The get() methods can be used to obtanis default value in the case the
- *required element
- * does not exist.
+ * 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.
+ * (The reason is an implementation detail.) A #CharReader will raise an
+ * exception if a bound is exceeded to avoid security holes in your app,
+ * but the Value API does *not* check bounds. That is the responsibility
+ * of the caller.
  */
 class JSON_API Value {
   friend class ValueIteratorBase;
-#ifdef JSON_VALUE_USE_INTERNAL_MAP
-  friend class ValueInternalLink;
-  friend class ValueInternalMap;
-#endif
-public:
-  typedef std::vector<std::string> Members;
-  typedef ValueIterator iterator;
-  typedef ValueConstIterator const_iterator;
-  typedef Json::UInt UInt;
-  typedef Json::Int Int;
-#if defined(JSON_HAS_INT64)
-  typedef Json::UInt64 UInt64;
-  typedef Json::Int64 Int64;
-#endif // defined(JSON_HAS_INT64)
-  typedef Json::LargestInt LargestInt;
-  typedef Json::LargestUInt LargestUInt;
-  typedef Json::ArrayIndex ArrayIndex;
 
+public:
+  using Members = std::vector<String>;
+  using iterator = ValueIterator;
+  using const_iterator = ValueConstIterator;
+  using UInt = Json::UInt;
+  using Int = Json::Int;
+#if defined(JSON_HAS_INT64)
+  using UInt64 = Json::UInt64;
+  using Int64 = Json::Int64;
+#endif // defined(JSON_HAS_INT64)
+  using LargestInt = Json::LargestInt;
+  using LargestUInt = Json::LargestUInt;
+  using ArrayIndex = Json::ArrayIndex;
+
+  // Required for boost integration, e. g. BOOST_TEST
+  using value_type = std::string;
+
+#if JSON_USE_NULLREF
+  // Binary compatibility kludges, do not use.
   static const Value& null;
+  static const Value& nullRef;
+#endif
+
+  // null and nullRef are deprecated, use this instead.
+  static Value const& nullSingleton();
+
   /// Minimum signed integer value that can be stored in a Json::Value.
-  static 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
-#ifndef JSON_VALUE_USE_INTERNAL_MAP
   class CZString {
   public:
-    enum DuplicationPolicy {
-      noDuplication = 0,
-      duplicate,
-      duplicateOnCopy
-    };
+    enum DuplicationPolicy { noDuplication = 0, duplicate, duplicateOnCopy };
     CZString(ArrayIndex index);
-    CZString(const char* cstr, DuplicationPolicy allocate);
-    CZString(const CZString& other);
+    CZString(char const* str, unsigned length, DuplicationPolicy allocate);
+    CZString(CZString const& other);
+    CZString(CZString&& other);
     ~CZString();
-    CZString& operator=(CZString other);
-    bool operator<(const CZString& other) const;
-    bool operator==(const CZString& other) const;
+    CZString& operator=(const CZString& other);
+    CZString& operator=(CZString&& other);
+
+    bool operator<(CZString const& other) const;
+    bool operator==(CZString const& other) const;
     ArrayIndex index() const;
-    const char* c_str() const;
+    // const char* c_str() const; ///< \deprecated
+    char const* data() const;
+    unsigned length() const;
     bool isStaticString() const;
 
   private:
     void swap(CZString& other);
-    const char* cstr_;
-    ArrayIndex index_;
+
+    struct StringStorage {
+      unsigned policy_ : 2;
+      unsigned length_ : 30; // 1GB max
+    };
+
+    char const* cstr_; // actually, a prefixed string, unless policy is noDup
+    union {
+      ArrayIndex index_;
+      StringStorage storage_;
+    };
   };
 
 public:
-#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 JSON_VALUE_USE_INTERNAL_MAP
 #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);
@@ -217,50 +320,69 @@
   Value(UInt64 value);
 #endif // if defined(JSON_HAS_INT64)
   Value(double value);
-  Value(const char* value);
-  Value(const char* beginValue, const char* endValue);
-  /** \brief Constructs a value from a static string.
-
+  Value(const char* value); ///< Copy til first 0. (NULL causes to seg-fault.)
+  Value(const char* begin, const char* end); ///< Copy all, incl zeroes.
+  /**
+   * \brief Constructs a value from a static string.
+   *
    * Like other value string constructor but do not duplicate the string for
-   * internal storage. The given string must remain alive after the call to this
-   * constructor.
+   * internal storage. The given string must remain alive after the call to
+   * this constructor.
+   *
+   * \note This works only for null-terminated strings. (We cannot change the
+   * size of this class, so we have nowhere to store the length, which might be
+   * computed later for various operations.)
+   *
    * Example of usage:
-   * \code
-   * Json::Value aValue( StaticString("some text") );
-   * \endcode
+   *   \code
+   *   static StaticString foo("some text");
+   *   Json::Value aValue(foo);
+   *   \endcode
    */
   Value(const StaticString& value);
-  Value(const std::string& value);
-#ifdef JSON_USE_CPPTL
-  Value(const CppTL::ConstString& value);
-#endif
+  Value(const String& value);
   Value(bool value);
+  Value(std::nullptr_t ptr) = delete;
   Value(const Value& other);
+  Value(Value&& other);
   ~Value();
 
-  Value& operator=(Value other);
-  /// Swap values.
-  /// \note Currently, comments are intentionally not swapped, for
-  /// both logic and efficiency.
+  /// \note Overwrite existing comments. To preserve comments, use
+  /// #swapPayload().
+  Value& operator=(const Value& other);
+  Value& operator=(Value&& other);
+
+  /// Swap everything.
   void swap(Value& other);
+  /// Swap values but leave comments and source offsets in place.
+  void swapPayload(Value& other);
+
+  /// copy everything.
+  void copy(const Value& other);
+  /// copy values but leave comments and source offsets in place.
+  void copyPayload(const Value& other);
 
   ValueType type() const;
 
+  /// Compare payload only, not comments etc.
   bool operator<(const Value& other) const;
   bool operator<=(const Value& other) const;
   bool operator>=(const Value& other) const;
   bool operator>(const Value& other) const;
-
   bool operator==(const Value& other) const;
   bool operator!=(const Value& other) const;
-
   int compare(const Value& other) const;
 
-  const char* asCString() const;
-  std::string asString() const;
-#ifdef JSON_USE_CPPTL
-  CppTL::ConstString asConstString() const;
+  const char* asCString() const; ///< Embedded zeroes could cause you trouble!
+#if JSONCPP_USING_SECURE_MEMORY
+  unsigned getCStringLength() const; // Allows you to understand the length of
+                                     // the CString
 #endif
+  String asString() const; ///< Embedded zeroes are possible.
+  /** Get raw char* of string-value.
+   *  \return false if !string. (Seg-fault if str or end are NULL.)
+   */
+  bool getString(char const** begin, char const** end) const;
   Int asInt() const;
   UInt asUInt() const;
 #if defined(JSON_HAS_INT64)
@@ -286,6 +408,10 @@
   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
@@ -295,50 +421,41 @@
   /// otherwise, false.
   bool empty() const;
 
-  /// Return isNull()
-  bool operator!() const;
+  /// Return !isNull()
+  explicit operator bool() const;
 
   /// Remove all object members and array elements.
   /// \pre type() is arrayValue, objectValue, or nullValue
   /// \post type() is unchanged
   void clear();
 
-  /// Resize the array to 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;
@@ -346,63 +463,96 @@
   ///
   /// Equivalent to jsonvalue[jsonvalue.size()] = value;
   Value& append(const Value& value);
+  Value& append(Value&& value);
+
+  /// \brief Insert value in array at specific index
+  bool insert(ArrayIndex index, const Value& newValue);
+  bool insert(ArrayIndex index, Value&& newValue);
 
   /// Access an object value by name, create a null member if it does not exist.
+  /// \note Because of our implementation, keys are limited to 2^30 -1 chars.
+  /// Exceeding that will cause an exception.
   Value& operator[](const char* key);
   /// Access an object value by name, returns null if there is no member with
   /// that name.
   const Value& operator[](const char* key) const;
   /// Access an object value by name, create a null member if it does not exist.
-  Value& operator[](const std::string& key);
+  /// \param key may contain embedded nulls.
+  Value& operator[](const String& key);
   /// Access an object value by name, returns null if there is no member with
   /// that name.
-  const Value& operator[](const std::string& key) const;
+  /// \param key may contain embedded nulls.
+  const Value& operator[](const String& key) const;
   /** \brief Access an object value by name, create a null member if it does not
-   exist.
-
-   * If the object as 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.
-  Value get(const std::string& key, const Value& defaultValue) const;
-#ifdef JSON_USE_CPPTL
+  /// \note deep copy
+  /// \note key may contain embedded nulls.
+  Value get(const char* begin, const char* end,
+            const Value& defaultValue) const;
   /// Return the member named key if it exist, defaultValue otherwise.
-  Value get(const CppTL::ConstString& key, const Value& defaultValue) const;
-#endif
+  /// \note deep copy
+  /// \param key may contain embedded nulls.
+  Value get(const String& key, const Value& defaultValue) const;
+  /// Most general and efficient version of isMember()const, get()const,
+  /// and operator[]const
+  /// \note As stated elsewhere, behavior is undefined if (end-begin) >= 2^30
+  Value const* find(char const* begin, char const* end) const;
+  /// Most general and efficient version of object-mutators.
+  /// \note As stated elsewhere, behavior is undefined if (end-begin) >= 2^30
+  /// \return non-zero, but JSON_ASSERT if this is neither object nor nullValue.
+  Value* demand(char const* begin, char const* end);
   /// \brief Remove and return the named member.
   ///
   /// Do nothing if it did not exist.
-  /// \return the removed Value, or null.
   /// \pre type() is objectValue or nullValue
   /// \post type() is unchanged
-  Value removeMember(const char* key);
+  void removeMember(const char* key);
   /// Same as removeMember(const char*)
-  Value removeMember(const std::string& key);
+  /// \param key may contain embedded nulls.
+  void removeMember(const String& key);
+  /// Same as removeMember(const char* begin, const char* end, Value* removed),
+  /// but 'key' is null-terminated.
+  bool removeMember(const char* key, Value* removed);
+  /** \brief Remove the named map member.
+   *
+   *  Update 'removed' iff removed.
+   *  \param key may contain embedded nulls.
+   *  \return true iff removed (no exceptions)
+   */
+  bool removeMember(String const& key, Value* removed);
+  /// Same as removeMember(String const& key, Value* removed)
+  bool removeMember(const char* begin, const char* end, Value* removed);
+  /** \brief Remove the indexed array element.
+   *
+   *  O(n) expensive operations.
+   *  Update 'removed' iff removed.
+   *  \return true if removed (no exceptions)
+   */
+  bool removeIndex(ArrayIndex index, Value* removed);
 
   /// Return true if the object has a member named key.
+  /// \note 'key' must be null-terminated.
   bool isMember(const char* key) const;
   /// Return true if the object has a member named key.
-  bool isMember(const std::string& key) const;
-#ifdef JSON_USE_CPPTL
-  /// Return true if the object has a member named key.
-  bool isMember(const CppTL::ConstString& key) const;
-#endif
+  /// \param key may contain embedded nulls.
+  bool isMember(const String& key) const;
+  /// Same as isMember(String const& key)const
+  bool isMember(const char* begin, const char* end) const;
 
   /// \brief Return a list of the member names.
   ///
@@ -411,20 +561,22 @@
   /// \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(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, CommentPlacement placement);
+  void setComment(const char* comment, size_t len, CommentPlacement placement) {
+    setComment(String(comment, len), placement);
+  }
   /// Comments must be //... or /* ... */
-  void setComment(const std::string& comment, CommentPlacement placement);
+  void setComment(String comment, CommentPlacement placement);
   bool hasComment(CommentPlacement placement) const;
   /// Include delimiters and embedded newlines.
-  std::string getComment(CommentPlacement placement) const;
+  String getComment(CommentPlacement placement) const;
 
-  std::string toStyledString() const;
+  String toStyledString() const;
 
   const_iterator begin() const;
   const_iterator end() const;
@@ -434,37 +586,25 @@
 
   // Accessors for the [start, limit) range of bytes within the JSON text from
   // which this value was parsed, if any.
-  void setOffsetStart(size_t start);
-  void setOffsetLimit(size_t limit);
-  size_t getOffsetStart() const;
-  size_t getOffsetLimit() const;
+  void setOffsetStart(ptrdiff_t start);
+  void setOffsetLimit(ptrdiff_t limit);
+  ptrdiff_t getOffsetStart() const;
+  ptrdiff_t getOffsetLimit() const;
 
 private:
-  void initBasic(ValueType type, bool allocated = false);
-
-  Value& resolveReference(const char* key, bool isStatic);
-
-#ifdef JSON_VALUE_USE_INTERNAL_MAP
-  inline bool isItemAvailable() const { return itemIsUsed_ == 0; }
-
-  inline void setItemUsed(bool isUsed = true) { itemIsUsed_ = isUsed ? 1 : 0; }
-
-  inline bool isMemberNameStatic() const { return memberNameIsStatic_ == 0; }
-
-  inline void setMemberNameIsStatic(bool isStatic) {
-    memberNameIsStatic_ = isStatic ? 1 : 0;
+  void setType(ValueType v) {
+    bits_.value_type_ = static_cast<unsigned char>(v);
   }
-#endif // # ifdef JSON_VALUE_USE_INTERNAL_MAP
+  bool isAllocated() const { return bits_.allocated_; }
+  void setIsAllocated(bool v) { bits_.allocated_ = v; }
 
-private:
-  struct CommentInfo {
-    CommentInfo();
-    ~CommentInfo();
+  void initBasic(ValueType type, bool allocated = false);
+  void dupPayload(const Value& other);
+  void releasePayload();
+  void dupMeta(const Value& other);
 
-    void setComment(const char* text);
-
-    char* comment_;
-  };
+  Value& resolveReference(const char* key);
+  Value& resolveReference(const char* key, const char* end);
 
   // struct MemberNamesTransform
   //{
@@ -480,28 +620,70 @@
     LargestUInt uint_;
     double real_;
     bool bool_;
-    char* string_;
-#ifdef JSON_VALUE_USE_INTERNAL_MAP
-    ValueInternalArray* array_;
-    ValueInternalMap* map_;
-#else
+    char* string_; // if allocated_, ptr to { unsigned, char[] }.
     ObjectValues* map_;
-#endif
   } value_;
-  ValueType type_ : 8;
-  int allocated_ : 1; // Notes: if declared as bool, bitfield is useless.
-#ifdef JSON_VALUE_USE_INTERNAL_MAP
-  unsigned int itemIsUsed_ : 1; // used by the ValueInternalMap container.
-  int memberNameIsStatic_ : 1;  // used by the ValueInternalMap container.
-#endif
-  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.
-  size_t start_;
-  size_t limit_;
+  ptrdiff_t start_;
+  ptrdiff_t limit_;
 };
 
+template <> inline bool Value::as<bool>() const { return asBool(); }
+template <> inline bool Value::is<bool>() const { return isBool(); }
+
+template <> inline Int Value::as<Int>() const { return asInt(); }
+template <> inline bool Value::is<Int>() const { return isInt(); }
+
+template <> inline UInt Value::as<UInt>() const { return asUInt(); }
+template <> inline bool Value::is<UInt>() const { return isUInt(); }
+
+#if defined(JSON_HAS_INT64)
+template <> inline Int64 Value::as<Int64>() const { return asInt64(); }
+template <> inline bool Value::is<Int64>() const { return isInt64(); }
+
+template <> inline UInt64 Value::as<UInt64>() const { return asUInt64(); }
+template <> inline bool Value::is<UInt64>() const { return isUInt64(); }
+#endif
+
+template <> inline double Value::as<double>() const { return asDouble(); }
+template <> inline bool Value::is<double>() const { return isDouble(); }
+
+template <> inline String Value::as<String>() const { return asString(); }
+template <> inline bool Value::is<String>() const { return isString(); }
+
+/// These `as` specializations are type conversions, and do not have a
+/// corresponding `is`.
+template <> inline float Value::as<float>() const { return asFloat(); }
+template <> inline const char* Value::as<const char*>() const {
+  return asCString();
+}
+
 /** \brief Experimental and untested: represents an element of the "path" to
  * access a node.
  */
@@ -512,17 +694,13 @@
   PathArgument();
   PathArgument(ArrayIndex index);
   PathArgument(const char* key);
-  PathArgument(const std::string& key);
+  PathArgument(String key);
 
 private:
-  enum Kind {
-    kindNone = 0,
-    kindIndex,
-    kindKey
-  };
-  std::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.
@@ -534,12 +712,11 @@
  * - ".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 std::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(),
@@ -552,397 +729,68 @@
   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 std::string& path, const InArgs& in);
-  void addPathInArg(const std::string& path,
-                    const InArgs& in,
-                    InArgs::const_iterator& itInArg,
-                    PathArgument::Kind kind);
-  void invalidPath(const std::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_;
 };
 
-#ifdef JSON_VALUE_USE_INTERNAL_MAP
-/** \brief Allocator to customize Value internal map.
- * Below is an example of a simple implementation (default implementation
- actually
- * use memory pool for speed).
- * \code
-   class DefaultValueMapAllocator : public ValueMapAllocator
-   {
-   public: // overridden from ValueMapAllocator
-      virtual ValueInternalMap *newMap()
-      {
-         return new ValueInternalMap();
-      }
-
-      virtual ValueInternalMap *newMapCopy( const ValueInternalMap &other )
-      {
-         return new ValueInternalMap( other );
-      }
-
-      virtual void destructMap( ValueInternalMap *map )
-      {
-         delete map;
-      }
-
-      virtual ValueInternalLink *allocateMapBuckets( unsigned int size )
-      {
-         return new ValueInternalLink[size];
-      }
-
-      virtual void releaseMapBuckets( ValueInternalLink *links )
-      {
-         delete [] links;
-      }
-
-      virtual ValueInternalLink *allocateMapLink()
-      {
-         return new ValueInternalLink();
-      }
-
-      virtual void releaseMapLink( ValueInternalLink *link )
-      {
-         delete link;
-      }
-   };
- * \endcode
- */
-class JSON_API ValueMapAllocator {
-public:
-  virtual ~ValueMapAllocator();
-  virtual ValueInternalMap* newMap() = 0;
-  virtual ValueInternalMap* newMapCopy(const ValueInternalMap& other) = 0;
-  virtual void destructMap(ValueInternalMap* map) = 0;
-  virtual ValueInternalLink* allocateMapBuckets(unsigned int size) = 0;
-  virtual void releaseMapBuckets(ValueInternalLink* links) = 0;
-  virtual ValueInternalLink* allocateMapLink() = 0;
-  virtual void releaseMapLink(ValueInternalLink* link) = 0;
-};
-
-/** \brief ValueInternalMap hash-map bucket chain link (for internal use only).
- * \internal previous_ & next_ allows for bidirectional traversal.
- */
-class JSON_API ValueInternalLink {
-public:
-  enum {
-    itemPerLink = 6
-  }; // sizeof(ValueInternalLink) = 128 on 32 bits architecture.
-  enum InternalFlags {
-    flagAvailable = 0,
-    flagUsed = 1
-  };
-
-  ValueInternalLink();
-
-  ~ValueInternalLink();
-
-  Value items_[itemPerLink];
-  char* keys_[itemPerLink];
-  ValueInternalLink* previous_;
-  ValueInternalLink* next_;
-};
-
-/** \brief A linked page based hash-table implementation used internally by
- *Value.
- * \internal ValueInternalMap is a tradional bucket based hash-table, with a
- *linked
- * list in each bucket to handle collision. There is an addional twist in that
- * each node of the collision linked list is a page containing a fixed amount of
- * value. This provides a better compromise between memory usage and speed.
- *
- * Each bucket is made up of a chained list of ValueInternalLink. The last
- * link of a given bucket can be found in the 'previous_' field of the following
- *bucket.
- * The last link of the last bucket is stored in tailLink_ as it has no
- *following bucket.
- * Only the last link of a bucket may contains 'available' item. The last link
- *always
- * contains at least one element unless is it the bucket one very first link.
- */
-class JSON_API ValueInternalMap {
-  friend class ValueIteratorBase;
-  friend class Value;
-
-public:
-  typedef unsigned int HashKey;
-  typedef unsigned int BucketIndex;
-
-#ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
-  struct IteratorState {
-    IteratorState() : map_(0), link_(0), itemIndex_(0), bucketIndex_(0) {}
-    ValueInternalMap* map_;
-    ValueInternalLink* link_;
-    BucketIndex itemIndex_;
-    BucketIndex bucketIndex_;
-  };
-#endif // ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
-
-  ValueInternalMap();
-  ValueInternalMap(const ValueInternalMap& other);
-  ValueInternalMap& operator=(ValueInternalMap other);
-  ~ValueInternalMap();
-
-  void swap(ValueInternalMap& other);
-
-  BucketIndex size() const;
-
-  void clear();
-
-  bool reserveDelta(BucketIndex growth);
-
-  bool reserve(BucketIndex newItemCount);
-
-  const Value* find(const char* key) const;
-
-  Value* find(const char* key);
-
-  Value& resolveReference(const char* key, bool isStatic);
-
-  void remove(const char* key);
-
-  void doActualRemove(ValueInternalLink* link,
-                      BucketIndex index,
-                      BucketIndex bucketIndex);
-
-  ValueInternalLink*& getLastLinkInBucket(BucketIndex bucketIndex);
-
-  Value& setNewItem(const char* key,
-                    bool isStatic,
-                    ValueInternalLink* link,
-                    BucketIndex index);
-
-  Value& unsafeAdd(const char* key, bool isStatic, HashKey hashedKey);
-
-  HashKey hash(const char* key) const;
-
-  int compare(const ValueInternalMap& other) const;
-
-private:
-  void makeBeginIterator(IteratorState& it) const;
-  void makeEndIterator(IteratorState& it) const;
-  static bool equals(const IteratorState& x, const IteratorState& other);
-  static void increment(IteratorState& iterator);
-  static void incrementBucket(IteratorState& iterator);
-  static void decrement(IteratorState& iterator);
-  static const char* key(const IteratorState& iterator);
-  static const char* key(const IteratorState& iterator, bool& isStatic);
-  static Value& value(const IteratorState& iterator);
-  static int distance(const IteratorState& x, const IteratorState& y);
-
-private:
-  ValueInternalLink* buckets_;
-  ValueInternalLink* tailLink_;
-  BucketIndex bucketsSize_;
-  BucketIndex itemCount_;
-};
-
-/** \brief A simplified deque implementation used internally by Value.
-* \internal
-* It is based on a list of fixed "page", each page contains a fixed number of
-*items.
-* Instead of using a linked-list, a array of pointer is used for fast item
-*look-up.
-* Look-up for an element is as follow:
-* - compute page index: pageIndex = itemIndex / itemsPerPage
-* - look-up item in page: pages_[pageIndex][itemIndex % itemsPerPage]
-*
-* Insertion is amortized constant time (only the array containing the index of
-*pointers
-* need to be reallocated when items are appended).
-*/
-class JSON_API ValueInternalArray {
-  friend class Value;
-  friend class ValueIteratorBase;
-
-public:
-  enum {
-    itemsPerPage = 8
-  }; // should be a power of 2 for fast divide and modulo.
-  typedef Value::ArrayIndex ArrayIndex;
-  typedef unsigned int PageIndex;
-
-#ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
-  struct IteratorState // Must be a POD
-      {
-    IteratorState() : array_(0), currentPageIndex_(0), currentItemIndex_(0) {}
-    ValueInternalArray* array_;
-    Value** currentPageIndex_;
-    unsigned int currentItemIndex_;
-  };
-#endif // ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
-
-  ValueInternalArray();
-  ValueInternalArray(const ValueInternalArray& other);
-  ValueInternalArray& operator=(ValueInternalArray other);
-  ~ValueInternalArray();
-  void swap(ValueInternalArray& other);
-
-  void clear();
-  void resize(ArrayIndex newSize);
-
-  Value& resolveReference(ArrayIndex index);
-
-  Value* find(ArrayIndex index) const;
-
-  ArrayIndex size() const;
-
-  int compare(const ValueInternalArray& other) const;
-
-private:
-  static bool equals(const IteratorState& x, const IteratorState& other);
-  static void increment(IteratorState& iterator);
-  static void decrement(IteratorState& iterator);
-  static Value& dereference(const IteratorState& iterator);
-  static Value& unsafeDereference(const IteratorState& iterator);
-  static int distance(const IteratorState& x, const IteratorState& y);
-  static ArrayIndex indexOf(const IteratorState& iterator);
-  void makeBeginIterator(IteratorState& it) const;
-  void makeEndIterator(IteratorState& it) const;
-  void makeIterator(IteratorState& it, ArrayIndex index) const;
-
-  void makeIndexValid(ArrayIndex index);
-
-  Value** pages_;
-  ArrayIndex size_;
-  PageIndex pageCount_;
-};
-
-/** \brief Experimental: do not use. Allocator to customize Value internal
-array.
- * Below is an example of a simple implementation (actual implementation use
- * memory pool).
-   \code
-class DefaultValueArrayAllocator : public ValueArrayAllocator
-{
-public: // overridden from ValueArrayAllocator
-virtual ~DefaultValueArrayAllocator()
-{
-}
-
-virtual ValueInternalArray *newArray()
-{
-   return new ValueInternalArray();
-}
-
-virtual ValueInternalArray *newArrayCopy( const ValueInternalArray &other )
-{
-   return new ValueInternalArray( other );
-}
-
-virtual void destruct( ValueInternalArray *array )
-{
-   delete array;
-}
-
-virtual void reallocateArrayPageIndex( Value **&indexes,
-                                       ValueInternalArray::PageIndex
-&indexCount,
-                                       ValueInternalArray::PageIndex
-minNewIndexCount )
-{
-   ValueInternalArray::PageIndex newIndexCount = (indexCount*3)/2 + 1;
-   if ( minNewIndexCount > newIndexCount )
-      newIndexCount = minNewIndexCount;
-   void *newIndexes = realloc( indexes, sizeof(Value*) * newIndexCount );
-   if ( !newIndexes )
-      throw std::bad_alloc();
-   indexCount = newIndexCount;
-   indexes = static_cast<Value **>( newIndexes );
-}
-virtual void releaseArrayPageIndex( Value **indexes,
-                                    ValueInternalArray::PageIndex indexCount )
-{
-   if ( indexes )
-      free( indexes );
-}
-
-virtual Value *allocateArrayPage()
-{
-   return static_cast<Value *>( malloc( sizeof(Value) *
-ValueInternalArray::itemsPerPage ) );
-}
-
-virtual void releaseArrayPage( Value *value )
-{
-   if ( value )
-      free( value );
-}
-};
-   \endcode
- */
-class JSON_API ValueArrayAllocator {
-public:
-  virtual ~ValueArrayAllocator();
-  virtual ValueInternalArray* newArray() = 0;
-  virtual ValueInternalArray* newArrayCopy(const ValueInternalArray& other) = 0;
-  virtual void destructArray(ValueInternalArray* array) = 0;
-  /** \brief Reallocate array page index.
-   * Reallocates an array of pointer on each page.
-   * \param indexes [input] pointer on the current index. May be \c NULL.
-   *                [output] pointer on the new index of at least
-   *                         \a minNewIndexCount pages.
-   * \param indexCount [input] current number of pages in the index.
-   *                   [output] number of page the reallocated index can handle.
-   *                            \b MUST be >= \a minNewIndexCount.
-   * \param minNewIndexCount Minimum number of page the new index must be able
-   * to
-   *                         handle.
-   */
-  virtual void
-  reallocateArrayPageIndex(Value**& indexes,
-                           ValueInternalArray::PageIndex& indexCount,
-                           ValueInternalArray::PageIndex minNewIndexCount) = 0;
-  virtual void
-  releaseArrayPageIndex(Value** indexes,
-                        ValueInternalArray::PageIndex indexCount) = 0;
-  virtual Value* allocateArrayPage() = 0;
-  virtual void releaseArrayPage(Value* value) = 0;
-};
-#endif // #ifdef JSON_VALUE_USE_INTERNAL_MAP
-
 /** \brief base class for Value iterators.
  *
  */
 class JSON_API ValueIteratorBase {
 public:
-  typedef std::bidirectional_iterator_tag iterator_category;
-  typedef unsigned int size_t;
-  typedef int difference_type;
-  typedef ValueIteratorBase SelfType;
-
-  ValueIteratorBase();
-#ifndef JSON_VALUE_USE_INTERNAL_MAP
-  explicit ValueIteratorBase(const Value::ObjectValues::iterator& current);
-#else
-  ValueIteratorBase(const ValueInternalArray::IteratorState& state);
-  ValueIteratorBase(const ValueInternalMap::IteratorState& state);
-#endif
+  using iterator_category = std::bidirectional_iterator_tag;
+  using size_t = unsigned int;
+  using difference_type = int;
+  using SelfType = ValueIteratorBase;
 
   bool operator==(const SelfType& other) const { return isEqual(other); }
 
   bool operator!=(const SelfType& other) const { return !isEqual(other); }
 
   difference_type operator-(const SelfType& other) const {
-    return computeDistance(other);
+    return other.computeDistance(*this);
   }
 
   /// Return either the index or the member name of the referenced value as a
   /// Value.
   Value key() const;
 
-  /// Return the index of the referenced Value. -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.
+  String name() const;
+
   /// Return the member name of the referenced Value. "" if it is not an
   /// objectValue.
-  const char* memberName() const;
+  /// \deprecated This cannot be used for UTF-8 strings, since there can be
+  /// embedded nulls.
+  JSONCPP_DEPRECATED("Use `key = name();` instead.")
+  char const* memberName() const;
+  /// Return the member name of the referenced Value, or NULL if it is not an
+  /// objectValue.
+  /// \note Better version than memberName(). Allows embedded nulls.
+  char const* memberName(char const** end) const;
 
 protected:
-  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();
 
@@ -955,17 +803,15 @@
   void copy(const SelfType& other);
 
 private:
-#ifndef JSON_VALUE_USE_INTERNAL_MAP
   Value::ObjectValues::iterator current_;
   // Indicates that iterator is for a null value.
-  bool isNull_;
-#else
-  union {
-    ValueInternalArray::IteratorState array_;
-    ValueInternalMap::IteratorState map_;
-  } iterator_;
-  bool isArray_;
-#endif
+  bool isNull_{true};
+
+public:
+  // For some reason, BORLAND needs these at the end, rather
+  // than earlier. No idea why.
+  ValueIteratorBase();
+  explicit ValueIteratorBase(const Value::ObjectValues::iterator& current);
 };
 
 /** \brief const iterator for object and array value.
@@ -975,24 +821,21 @@
   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.
- */
-#ifndef JSON_VALUE_USE_INTERNAL_MAP
+  /*! \internal Use by Value to create an iterator.
+   */
   explicit ValueConstIterator(const Value::ObjectValues::iterator& current);
-#else
-  ValueConstIterator(const ValueInternalArray::IteratorState& state);
-  ValueConstIterator(const ValueInternalMap::IteratorState& state);
-#endif
+
 public:
   SelfType& operator=(const ValueIteratorBase& other);
 
@@ -1029,26 +872,22 @@
   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();
-  ValueIterator(const ValueConstIterator& other);
+  explicit ValueIterator(const ValueConstIterator& other);
   ValueIterator(const ValueIterator& other);
 
 private:
-/*! \internal Use by Value to create an iterator.
- */
-#ifndef JSON_VALUE_USE_INTERNAL_MAP
+  /*! \internal Use by Value to create an iterator.
+   */
   explicit ValueIterator(const Value::ObjectValues::iterator& current);
-#else
-  ValueIterator(const ValueInternalArray::IteratorState& state);
-  ValueIterator(const ValueInternalMap::IteratorState& state);
-#endif
+
 public:
   SelfType& operator=(const SelfType& other);
 
@@ -1074,15 +913,23 @@
     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(); }
 };
 
+inline void swap(Value& a, Value& b) { a.swap(b); }
+
 } // namespace Json
 
+#pragma pack(pop)
+
 #if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 #pragma warning(pop)
 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 
-#endif // CPPTL_JSON_H_INCLUDED
+#endif // JSON_H_INCLUDED
diff --git a/include/json/version.h b/include/json/version.h
new file mode 100644
index 0000000..5b9783d
--- /dev/null
+++ b/include/json/version.h
@@ -0,0 +1,28 @@
+#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
diff --git a/include/json/writer.h b/include/json/writer.h
index dc9e46f..fb0852a 100644
--- a/include/json/writer.h
+++ b/include/json/writer.h
@@ -1,4 +1,4 @@
-// Copyright 2007-2010 Baptiste Lepilleur
+// 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
@@ -9,27 +9,147 @@
 #if !defined(JSON_IS_AMALGAMATION)
 #include "value.h"
 #endif // if !defined(JSON_IS_AMALGAMATION)
-#include <vector>
+#include <ostream>
 #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)
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING) && defined(_MSC_VER)
 #pragma warning(push)
 #pragma warning(disable : 4251)
 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 
+#pragma pack(push, 8)
+
 namespace Json {
 
 class Value;
 
-/** \brief Abstract class for writers.
+/**
+ *
+ * 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 Writer {
+class JSON_API StreamWriter {
+protected:
+  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
+   */
+  virtual int write(Value const& root, OStream* sout) = 0;
+
+  /** \brief A simple abstract factory.
+   */
+  class JSON_API Factory {
+  public:
+    virtual ~Factory();
+    /** \brief Allocate a CharReader via operator new().
+     * \throw std::exception if something goes wrong (e.g. invalid settings)
+     */
+    virtual StreamWriter* newStreamWriter() const = 0;
+  }; // Factory
+};   // StreamWriter
+
+/** \brief Write into stringstream, then return string, for convenience.
+ * A StreamWriter will be created from the factory, used, and then deleted.
+ */
+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
+*/
+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>".
+   *  - 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() override;
+
+  /**
+   * \throw std::exception if something goes wrong (e.g. invalid settings)
+   */
+  StreamWriter* newStreamWriter() const override;
+
+  /** \return true if 'settings' are legal and consistent;
+   *   otherwise, indicate bad settings via 'invalid'.
+   */
+  bool validate(Json::Value* invalid) const;
+  /** A simple way to update a specific setting.
+   */
+  Value& operator[](const String& key);
+
+  /** Called by ctor, but you can use this to reset settings_.
+   * \pre 'settings' != NULL (but Json::null is fine)
+   * \remark Defaults:
+   * \snippet src/lib_json/json_writer.cpp StreamWriterBuilderDefaults
+   */
+  static void setDefaults(Json::Value* settings);
+};
+
+/** \brief Abstract class for writers.
+ * \deprecated Use StreamWriter. (And really, this is an implementation detail.)
+ */
+class JSONCPP_DEPRECATED("Use StreamWriter instead") JSON_API Writer {
 public:
   virtual ~Writer();
 
-  virtual std::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
@@ -37,19 +157,25 @@
  *
  * 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.
  */
-class JSON_API FastWriter : public Writer {
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4996) // Deriving from deprecated class
+#endif
+class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API FastWriter
+    : public Writer {
 public:
   FastWriter();
-  virtual ~FastWriter() {}
+  ~FastWriter() override = default;
 
   void enableYAMLCompatibility();
 
   /** \brief 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
+   * fed to a browser's JavaScript, it makes for smaller output and the
    * browser can handle the output just fine.
    */
   void dropNullPlaceholders();
@@ -57,16 +183,19 @@
   void omitEndingLineFeed();
 
 public: // overridden from Writer
-  virtual std::string write(const Value& root);
+  String write(const Value& root) override;
 
 private:
   void writeValue(const Value& value);
 
-  std::string document_;
-  bool yamlCompatiblityEnabled_;
-  bool dropNullPlaceholders_;
-  bool omitEndingLineFeed_;
+  String document_;
+  bool yamlCompatibilityEnabled_{false};
+  bool dropNullPlaceholders_{false};
+  bool omitEndingLineFeed_{false};
 };
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
 
 /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a
  *human friendly way.
@@ -90,42 +219,51 @@
  *#CommentPlacement.
  *
  * \sa Reader, Value, Value::setComment()
+ * \deprecated Use StreamWriterBuilder.
  */
-class JSON_API StyledWriter : public Writer {
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4996) // Deriving from deprecated class
+#endif
+class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API
+    StyledWriter : public Writer {
 public:
   StyledWriter();
-  virtual ~StyledWriter() {}
+  ~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.
    */
-  virtual std::string write(const Value& root);
+  String write(const Value& root) override;
 
 private:
   void writeValue(const Value& value);
   void writeArrayValue(const Value& value);
-  bool isMultineArray(const Value& value);
-  void pushValue(const std::string& value);
+  bool isMultilineArray(const Value& value);
+  void pushValue(const String& value);
   void writeIndent();
-  void writeWithIndent(const std::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 std::string normalizeEOL(const std::string& text);
+  static bool hasCommentForValue(const Value& value);
+  static String normalizeEOL(const String& text);
 
-  typedef std::vector<std::string> ChildValues;
+  using ChildValues = std::vector<String>;
 
   ChildValues childValues_;
-  std::string document_;
-  std::string indentString_;
-  int rightMargin_;
-  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)
+#endif
 
 /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a
  human friendly way,
@@ -149,13 +287,21 @@
  * If the Value have comments then they are outputed according to their
  #CommentPlacement.
  *
- * \param indentation Each level will be indented by this amount extra.
  * \sa Reader, Value, Value::setComment()
+ * \deprecated Use StreamWriterBuilder.
  */
-class JSON_API StyledStreamWriter {
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4996) // Deriving from deprecated class
+#endif
+class JSONCPP_DEPRECATED("Use StreamWriterBuilder instead") JSON_API
+    StyledStreamWriter {
 public:
-  StyledStreamWriter(std::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.
@@ -164,48 +310,56 @@
    * \note There is no point in deriving from Writer, since write() should not
    * return a value.
    */
-  void write(std::ostream& out, const Value& root);
+  void write(OStream& out, const Value& root);
 
 private:
   void writeValue(const Value& value);
   void writeArrayValue(const Value& value);
-  bool isMultineArray(const Value& value);
-  void pushValue(const std::string& value);
+  bool isMultilineArray(const Value& value);
+  void pushValue(const String& value);
   void writeIndent();
-  void writeWithIndent(const std::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 std::string normalizeEOL(const std::string& text);
+  static bool hasCommentForValue(const Value& value);
+  static String normalizeEOL(const String& text);
 
-  typedef std::vector<std::string> ChildValues;
+  using ChildValues = std::vector<String>;
 
   ChildValues childValues_;
-  std::ostream* document_;
-  std::string indentString_;
-  int rightMargin_;
-  std::string indentation_;
-  bool addChildValues_;
+  OStream* document_;
+  String indentString_;
+  unsigned int rightMargin_{74};
+  String indentation_;
+  bool addChildValues_ : 1;
+  bool indented_ : 1;
 };
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
 
 #if defined(JSON_HAS_INT64)
-std::string JSON_API valueToString(Int value);
-std::string JSON_API valueToString(UInt value);
+String JSON_API valueToString(Int value);
+String JSON_API valueToString(UInt value);
 #endif // if defined(JSON_HAS_INT64)
-std::string JSON_API valueToString(LargestInt value);
-std::string JSON_API valueToString(LargestUInt value);
-std::string JSON_API valueToString(double value);
-std::string JSON_API valueToString(bool value);
-std::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 std::ostream& operator<<(std::ostream&, const Value& root);
+JSON_API OStream& operator<<(OStream&, const Value& root);
 
 } // namespace Json
 
+#pragma pack(pop)
+
 #if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
 #pragma warning(pop)
 #endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)