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diff --git a/include/jsoncons_ext/bson/bson.hpp b/include/jsoncons_ext/bson/bson.hpp
new file mode 100644
index 0000000..ec3192d
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson.hpp
@@ -0,0 +1,23 @@
+// Copyright 2013 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_BSON_HPP
+#define JSONCONS_BSON_BSON_HPP
+
+#include <string>
+#include <vector>
+#include <memory>
+#include <type_traits> // std::enable_if
+#include <istream> // std::basic_istream
+#include <jsoncons/json.hpp>
+#include <jsoncons/config/jsoncons_config.hpp>
+#include <jsoncons_ext/bson/bson_encoder.hpp>
+#include <jsoncons_ext/bson/bson_reader.hpp>
+#include <jsoncons_ext/bson/bson_cursor.hpp>
+#include <jsoncons_ext/bson/encode_bson.hpp>
+#include <jsoncons_ext/bson/decode_bson.hpp>
+
+#endif
diff --git a/include/jsoncons_ext/bson/bson_cursor.hpp b/include/jsoncons_ext/bson/bson_cursor.hpp
new file mode 100644
index 0000000..8baee53
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_cursor.hpp
@@ -0,0 +1,320 @@
+// Copyright 2018 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_BSON_CURSOR_HPP
+#define JSONCONS_BSON_BSON_CURSOR_HPP
+
+#include <memory> // std::allocator
+#include <string>
+#include <vector>
+#include <stdexcept>
+#include <system_error>
+#include <ios>
+#include <istream> // std::basic_istream
+#include <jsoncons/byte_string.hpp>
+#include <jsoncons/config/jsoncons_config.hpp>
+#include <jsoncons/json_visitor.hpp>
+#include <jsoncons/json_exception.hpp>
+#include <jsoncons/staj_cursor.hpp>
+#include <jsoncons/source.hpp>
+#include <jsoncons_ext/bson/bson_parser.hpp>
+
+namespace jsoncons { 
+namespace bson {
+
+template<class Source=jsoncons::binary_stream_source,class Allocator=std::allocator<char>>
+class basic_bson_cursor : public basic_staj_cursor<char>, private virtual ser_context
+{
+    using super_type = basic_staj_cursor<char>;
+public:
+    using source_type = Source;
+    using char_type = char;
+    using allocator_type = Allocator;
+private:
+    basic_bson_parser<Source,Allocator> parser_;
+    basic_staj_visitor<char_type> cursor_visitor_;
+    bool eof_;
+
+    // Noncopyable and nonmoveable
+    basic_bson_cursor(const basic_bson_cursor&) = delete;
+    basic_bson_cursor& operator=(const basic_bson_cursor&) = delete;
+
+public:
+    using string_view_type = string_view;
+
+    template <class Sourceable>
+    basic_bson_cursor(Sourceable&& source,
+                      const bson_decode_options& options = bson_decode_options(),
+                      const Allocator& alloc = Allocator())
+        : parser_(std::forward<Sourceable>(source), options, alloc), 
+          cursor_visitor_(accept_all),
+          eof_(false)
+    {
+        if (!done())
+        {
+            next();
+        }
+    }
+
+    // Constructors that set parse error codes
+
+    template <class Sourceable>
+    basic_bson_cursor(Sourceable&& source,
+                      std::error_code& ec)
+        : basic_bson_cursor(std::allocator_arg, Allocator(),
+                            std::forward<Sourceable>(source), 
+                            bson_decode_options(), 
+                            ec)
+    {
+    }
+
+    template <class Sourceable>
+    basic_bson_cursor(Sourceable&& source,
+                      const bson_decode_options& options,
+                      std::error_code& ec)
+        : basic_bson_cursor(std::allocator_arg, Allocator(),
+                            std::forward<Sourceable>(source), 
+                            options, 
+                            ec)
+    {
+    }
+
+    template <class Sourceable>
+    basic_bson_cursor(std::allocator_arg_t, const Allocator& alloc, 
+                      Sourceable&& source,
+                      const bson_decode_options& options,
+                      std::error_code& ec)
+       : parser_(std::forward<Sourceable>(source), options, alloc),
+         cursor_visitor_(accept_all),
+         eof_(false)
+    {
+        if (!done())
+        {
+            next(ec);
+        }
+    }
+
+    void reset()
+    {
+        parser_.reset();
+        cursor_visitor_.reset();
+        eof_ = false;
+        if (!done())
+        {
+            next();
+        }
+    }
+
+    template <class Sourceable>
+    void reset(Sourceable&& source)
+    {
+        parser_.reset(std::forward<Sourceable>(source));
+        cursor_visitor_.reset();
+        eof_ = false;
+        if (!done())
+        {
+            next();
+        }
+    }
+
+    void reset(std::error_code& ec)
+    {
+        parser_.reset();
+        cursor_visitor_.reset();
+        eof_ = false;
+        if (!done())
+        {
+            next(ec);
+        }
+    }
+
+    template <class Sourceable>
+    void reset(Sourceable&& source, std::error_code& ec)
+    {
+        parser_.reset(std::forward<Sourceable>(source));
+        cursor_visitor_.reset();
+        eof_ = false;
+        if (!done())
+        {
+            next(ec);
+        }
+    }
+
+    bool done() const override
+    {
+        return parser_.done();
+    }
+
+    void array_expected(std::error_code& ec) override
+    {
+        if (cursor_visitor_.event().event_type() == staj_event_type::begin_object)
+        {
+            parser_.array_expected(cursor_visitor_, ec);
+        }
+        else
+        { 
+            super_type::array_expected(ec);
+        }
+    }
+
+    const staj_event& current() const override
+    {
+        return cursor_visitor_.event();
+    }
+
+    void read_to(basic_json_visitor<char_type>& visitor) override
+    {
+        std::error_code ec;
+        read_to(visitor, ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec,parser_.line(),parser_.column()));
+        }
+    }
+
+    void read_to(basic_json_visitor<char_type>& visitor,
+                std::error_code& ec) override
+    {
+        if (staj_to_saj_event(cursor_visitor_.event(), visitor, *this, ec))
+        {
+            read_next(visitor, ec);
+        }
+    }
+
+    void next() override
+    {
+        std::error_code ec;
+        next(ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec,parser_.line(),parser_.column()));
+        }
+    }
+
+    void next(std::error_code& ec) override
+    {
+        read_next(ec);
+    }
+
+    const ser_context& context() const override
+    {
+        return *this;
+    }
+
+    bool eof() const
+    {
+        return eof_;
+    }
+
+    std::size_t line() const override
+    {
+        return parser_.line();
+    }
+
+    std::size_t column() const override
+    {
+        return parser_.column();
+    }
+
+    friend
+    staj_filter_view operator|(basic_bson_cursor& cursor, 
+                               std::function<bool(const staj_event&, const ser_context&)> pred)
+    {
+        return staj_filter_view(cursor, pred);
+    }
+
+#if !defined(JSONCONS_NO_DEPRECATED)
+
+    template <class Sourceable>
+    JSONCONS_DEPRECATED_MSG("Instead, use pipe syntax for filter")
+    basic_bson_cursor(Sourceable&& source,
+                      std::function<bool(const staj_event&, const ser_context&)> filter,
+                      std::error_code& ec)
+       : basic_bson_cursor(std::allocator_arg, Allocator(), 
+                           std::forward<Sourceable>(source), filter, ec)
+    {
+    }
+
+    template <class Sourceable>
+    JSONCONS_DEPRECATED_MSG("Instead, use pipe syntax for filter")
+    basic_bson_cursor(Sourceable&& source,
+                      std::function<bool(const staj_event&, const ser_context&)> filter,
+                      const bson_decode_options& options = bson_decode_options(),
+                      const Allocator& alloc = Allocator())
+       : parser_(std::forward<Sourceable>(source), options, alloc), 
+         cursor_visitor_(filter), 
+         eof_(false)
+    {
+        if (!done())
+        {
+            next();
+        }
+    }
+
+    template <class Sourceable>
+    JSONCONS_DEPRECATED_MSG("Instead, use pipe syntax for filter")
+    basic_bson_cursor(std::allocator_arg_t, const Allocator& alloc, 
+                      Sourceable&& source,
+                      std::function<bool(const staj_event&, const ser_context&)> filter, 
+                      std::error_code& ec)
+       : parser_(std::forward<Sourceable>(source),alloc), 
+         cursor_visitor_(filter),
+         eof_(false)
+    {
+        if (!done())
+        {
+            next(ec);
+        }
+    }
+
+    JSONCONS_DEPRECATED_MSG("Instead, use read_to(basic_json_visitor<char_type>&)")
+    void read(basic_json_visitor<char_type>& visitor)
+    {
+        read_to(visitor);
+    }
+
+    JSONCONS_DEPRECATED_MSG("Instead, use read_to(basic_json_visitor<char_type>&, std::error_code&)")
+    void read(basic_json_visitor<char_type>& visitor,
+                 std::error_code& ec) 
+    {
+        read_to(visitor, ec);
+    }
+#endif
+private:
+    static bool accept_all(const staj_event&, const ser_context&) 
+    {
+        return true;
+    }
+
+    void read_next(std::error_code& ec)
+    {
+        parser_.restart();
+        while (!parser_.stopped())
+        {
+            parser_.parse(cursor_visitor_, ec);
+            if (ec) return;
+        }
+    }
+
+    void read_next(basic_json_visitor<char_type>& visitor, std::error_code& ec)
+    {
+        parser_.restart();
+        while (!parser_.stopped())
+        {
+            parser_.parse(visitor, ec);
+            if (ec) return;
+        }
+    }
+};
+
+using bson_stream_cursor = basic_bson_cursor<jsoncons::binary_stream_source>;
+using bson_bytes_cursor = basic_bson_cursor<jsoncons::bytes_source>;
+
+} // namespace bson
+} // namespace jsoncons
+
+#endif
+
diff --git a/include/jsoncons_ext/bson/bson_decimal128.hpp b/include/jsoncons_ext/bson/bson_decimal128.hpp
new file mode 100644
index 0000000..b487a04
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_decimal128.hpp
@@ -0,0 +1,865 @@
+#ifndef JSONCONS_BSON_BSON_DECIMAL128_HPP
+#define JSONCONS_BSON_BSON_DECIMAL128_HPP
+
+/*
+ *  Implements decimal128_to_chars and decimal128_from_chars
+ *  
+ *  Based on the libjson functions bson_decimal128_to_string
+ *  and bson_decimal128_from_string_w_len, available at
+ *  https://github.com/mongodb/mongo-c-driver/blob/master/src/libbson/src/bson/bson-decimal128.h
+ *  and https://github.com/mongodb/mongo-c-driver/blob/master/src/libbson/src/bson/bson-decimal128.c
+ *  
+*/
+
+/*
+ * Copyright 2015 MongoDB, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <cstring>
+#include <ctype.h>
+#include <system_error>
+#include <algorithm>
+#include <jsoncons/config/jsoncons_config.hpp>
+
+namespace jsoncons { namespace bson {
+
+    struct decimal128_to_chars_result 
+    {
+        char* ptr;
+        std::errc ec;
+    };
+
+    struct decimal128_from_chars_result 
+    {
+        const char* ptr;
+        std::errc ec;
+    };
+
+/**
+ * BSON_DECIMAL128_STRING:
+ *
+ * The length of a decimal128 string (with null terminator).
+ *
+ * 1  for the sign
+ * 35 for digits and radix
+ * 2  for exponent indicator and sign
+ * 4  for exponent digits
+ */
+#define BSON_DECIMAL128_STRING 43
+
+    struct TP1 
+    { 
+        uint64_t low; 
+        uint64_t high; 
+
+        constexpr TP1() : low(0), high(0) {}
+        constexpr TP1(uint64_t hi, uint64_t lo) : low(lo), high(hi) {}
+    };
+    struct TP2 
+    { 
+        uint64_t high; 
+        uint64_t low; 
+
+        constexpr TP2() : high(0), low(0) {}
+        constexpr TP2(uint64_t hi, uint64_t lo) : high(hi), low(lo) {}
+    };
+
+    typedef std::conditional<
+        jsoncons::endian::native == jsoncons::endian::little,
+        TP1,
+        TP2
+    >::type decimal128_t;
+
+    inline
+    bool operator==(const decimal128_t& lhs, const decimal128_t& rhs)
+    {
+       return lhs.high == rhs.high && lhs.low == rhs.low;
+    }   
+
+    inline
+    bool operator!=(const decimal128_t& lhs, const decimal128_t& rhs)
+    {
+       return !(lhs == rhs);
+    }   
+
+    struct decimal128_limits
+    {
+        // The length of a decimal128 string (without null terminator).
+        //
+        // 1  for the sign
+        // 35 for digits and radix
+        // 2  for exponent indicator and sign
+        // 4  for exponent digits
+        static constexpr int buf_size = 42;  
+        static constexpr int exponent_max = 6111;
+        static constexpr int exponent_min = -6176;
+        static constexpr int exponent_bias = 6176;
+        static constexpr int max_digits = 34;
+
+        static constexpr decimal128_t nan() {return decimal128_t(0x7c00000000000000ull, 0);}
+        static constexpr decimal128_t infinity() {return decimal128_t(0x7800000000000000ull, 0);}
+        static constexpr decimal128_t neg_infinity() {return decimal128_t(0x7800000000000000ull + 0x8000000000000000ull, 0);}
+    };
+
+    inline
+    bool is_nan(decimal128_t dec) { return dec == decimal128_limits::nan(); }
+
+    inline
+    bool is_inf(decimal128_t dec) { return dec == decimal128_limits::infinity(); }
+
+    inline
+    bool is_neg_inf(decimal128_t dec) { return dec == decimal128_limits::neg_infinity(); }
+
+    /**
+     * bson_uint128_t:
+     *
+     * This struct represents a 128 bit integer.
+     */
+    typedef struct {
+       uint32_t parts[4]; /* 32-bit words stored high to low. */
+    } bson_uint128_t;
+
+    typedef struct {
+       uint64_t high, low;
+    } bson_uint128_6464_t;
+
+    namespace detail {
+    
+        /**
+         *------------------------------------------------------------------------------
+         *
+         * bson_uint128_divide1B --
+         *
+         *    This function divides a #bson_uint128_t by 1000000000 (1 billion) and
+         *    computes the quotient and remainder.
+         *
+         *    The remainder will contain 9 decimal digits for conversion to string.
+         *
+         * @value     The #bson_uint128_t operand.
+         * @quotient  A pointer to store the #bson_uint128_t quotient.
+         * @rem       A pointer to store the #uint64_t remainder.
+         *
+         * Returns:
+         *    The quotient at @quotient and the remainder at @rem.
+         *
+         * Side effects:
+         *    None.
+         *
+         *------------------------------------------------------------------------------
+         */
+
+        inline
+        void bson_uint128_divide1B (bson_uint128_t value,     /* IN */
+                                     bson_uint128_t *quotient, /* OUT */
+                                     uint32_t *rem)             /* OUT */
+        {
+            const uint32_t DIVISOR = 1000 * 1000 * 1000;
+            uint64_t _rem = 0;
+            int i = 0;
+            
+            if (!value.parts[0] && !value.parts[1] && !value.parts[2] &&
+                !value.parts[3]) {
+               *quotient = value;
+               *rem = 0;
+               return;
+            }
+            
+            for (i = 0; i <= 3; i++) {
+               _rem <<= 32; /* Adjust remainder to match value of next dividend */
+               _rem += value.parts[i]; /* Add the divided to _rem */
+               value.parts[i] = (uint32_t) (_rem / DIVISOR);
+               _rem %= DIVISOR; /* Store the remainder */
+            }
+            
+            *quotient = value;
+            *rem = (uint32_t) _rem;
+        }
+
+        /**
+         *-------------------------------------------------------------------------
+         *
+         * mul64x64 --
+         *
+         *    This function multiplies two &uint64_t into a &bson_uint128_6464_t.
+         *
+         * Returns:
+         *    The product of @left and @right.
+         *
+         * Side Effects:
+         *    None.
+         *
+         *-------------------------------------------------------------------------
+         */
+
+        inline
+        void mul_64x64 (uint64_t left,                 /* IN */
+                        uint64_t right,                /* IN */
+                        bson_uint128_6464_t *product) /* OUT */
+        {
+            uint64_t left_high, left_low, right_high, right_low, product_high,
+               product_mid, product_mid2, product_low;
+            bson_uint128_6464_t rt = {0,0};
+ 
+            if (!left && !right) {
+               *product = rt;
+               return;
+            }
+ 
+            left_high = left >> 32;
+            left_low = (uint32_t) left;
+            right_high = right >> 32;
+            right_low = (uint32_t) right;
+ 
+            product_high = left_high * right_high;
+            product_mid = left_high * right_low;
+            product_mid2 = left_low * right_high;
+            product_low = left_low * right_low;
+ 
+            product_high += product_mid >> 32;
+            product_mid = (uint32_t) product_mid + product_mid2 + (product_low >> 32);
+ 
+            product_high = product_high + (product_mid >> 32);
+            product_low = (product_mid << 32) + (uint32_t) product_low;
+ 
+            rt.high = product_high;
+            rt.low = product_low;
+            *product = rt;
+        }
+
+        /**
+         *------------------------------------------------------------------------------
+         *
+         * dec128_tolower --
+         *
+         *    This function converts the ASCII character @c to lowercase.  It is locale
+         *    insensitive (unlike the stdlib tolower).
+         *
+         * Returns:
+         *    The lowercased character.
+         */
+
+        inline
+        char dec128_tolower (char c)
+        {
+           if (isupper (c)) {
+              c += 32;
+           }
+
+           return c;
+        }
+
+        /**
+         *------------------------------------------------------------------------------
+         *
+         * dec128_istreq --
+         *
+         *    This function compares the null-terminated *ASCII* strings @a and @b
+         *    for case-insensitive equality.
+         *
+         * Returns:
+         *    true if the strings are equal, false otherwise.
+         */
+
+        inline
+        bool dec128_istreq (const char* a, const char* lasta,
+                            const char* b, const char* lastb)
+        {
+            while (!(a == lasta && b == lastb)) 
+            {
+               // strings are different lengths
+               if (a == lasta || b == lastb) 
+               {
+                  return false;
+               }
+         
+               if (dec128_tolower (*a) != dec128_tolower (*b)) {
+                  return false;
+               }
+         
+               a++;
+               b++;
+            }
+         
+            return true;
+        }
+
+    } // namespace detail
+
+
+    /**
+     *------------------------------------------------------------------------------
+     *
+     * decimal128_to_chars --
+     *
+     *    This function converts a BID formatted decimal128 value to string,
+     *    accepting a &decimal128_t as @dec.  The string is stored at @str.
+     *
+     * @dec : The BID formatted decimal to convert.
+     * @str : The output decimal128 string. At least %BSON_DECIMAL128_STRING
+     *characters.
+     *
+     * Returns:
+     *    None.
+     *
+     * Side effects:
+     *    None.
+     *
+     *------------------------------------------------------------------------------
+     */
+
+    inline
+    decimal128_to_chars_result decimal128_to_chars(char* first, char* last, const decimal128_t& dec)
+    {
+        const std::string bson_decimal128_inf = "Infinity";
+        const std::string bson_decimal128_nan = "NaN";
+
+        const uint32_t combination_mask = 0x1f;   /* Extract least significant 5 bits */
+        const uint32_t exponent_mask = 0x3fff;    /* Extract least significant 14 bits */
+        const uint32_t combination_infinity = 30; /* Value of combination field for Inf */
+        const uint32_t combination_nan = 31;      /* Value of combination field for NaN */
+        const uint32_t exponent_bias = 6176;      /* decimal128 exponent bias */
+
+        char* str_out = first;      /* output pointer in string */
+        char significand_str[35]; /* decoded significand digits */
+
+        /* Note: bits in this routine are referred to starting at 0, */
+        /* from the sign bit, towards the coefficient. */
+        uint32_t high;                   /* bits 0 - 31 */
+        uint32_t midh;                   /* bits 32 - 63 */
+        uint32_t midl;                   /* bits 64 - 95 */
+        uint32_t low;                    /* bits 96 - 127 */
+        uint32_t combination;            /* bits 1 - 5 */
+        uint32_t biased_exponent;        /* decoded biased exponent (14 bits) */
+        uint32_t significand_digits = 0; /* the number of significand digits */
+        uint32_t significand[36] = {0};  /* the base-10 digits in the significand */
+        uint32_t *significand_read = significand; /* read pointer into significand */
+        int32_t exponent;                         /* unbiased exponent */
+        int32_t scientific_exponent; /* the exponent if scientific notation is
+                                      * used */
+        bool is_zero = false;        /* true if the number is zero */
+ 
+        uint8_t significand_msb; /* the most signifcant significand bits (50-46) */
+        bson_uint128_t
+           significand128; /* temporary storage for significand decoding */
+ 
+        memset (significand_str, 0, sizeof (significand_str));
+ 
+        if ((int64_t) dec.high < 0) { /* negative */
+           *(str_out++) = '-';
+        }
+ 
+        low = (uint32_t) dec.low, midl = (uint32_t) (dec.low >> 32),
+        midh = (uint32_t) dec.high, high = (uint32_t) (dec.high >> 32);
+ 
+        /* Decode combination field and exponent */
+        combination = (high >> 26) & combination_mask;
+ 
+        if (JSONCONS_UNLIKELY ((combination >> 3) == 3)) {
+           /* Check for 'special' values */
+           if (combination == combination_infinity) { /* Infinity */
+               if (last-str_out >= static_cast<ptrdiff_t >(bson_decimal128_inf.size())) 
+               {
+                   std::memcpy(str_out, bson_decimal128_inf.data(), bson_decimal128_inf.size());
+                   str_out += bson_decimal128_inf.size();
+               }
+               *str_out = 0;
+              //strcpy_s (str_out, last-str_out, bson_decimal128_inf.c_str());
+              return decimal128_to_chars_result{str_out, std::errc()};
+           } else if (combination == combination_nan) { /* NaN */
+               /* first, not str_out, to erase the sign */
+               str_out = first;
+               if (last-str_out >= static_cast<ptrdiff_t >(bson_decimal128_nan.size())) 
+               {
+                   std::memcpy(str_out, bson_decimal128_nan.data(), bson_decimal128_nan.size());
+                   str_out += bson_decimal128_nan.size();
+               }
+               *str_out = 0;
+              //strcpy_s (first, last-first, bson_decimal128_nan.c_str());
+              /* we don't care about the NaN payload. */
+               return decimal128_to_chars_result{str_out, std::errc()};
+           } else {
+              biased_exponent = (high >> 15) & exponent_mask;
+              significand_msb = 0x8 + ((high >> 14) & 0x1);
+           }
+        } else {
+           significand_msb = (high >> 14) & 0x7;
+           biased_exponent = (high >> 17) & exponent_mask;
+        }
+ 
+        exponent = biased_exponent - exponent_bias;
+        /* Create string of significand digits */
+ 
+        /* Convert the 114-bit binary number represented by */
+        /* (high, midh, midl, low) to at most 34 decimal */
+        /* digits through modulo and division. */
+        significand128.parts[0] = (high & 0x3fff) + ((significand_msb & 0xf) << 14);
+        significand128.parts[1] = midh;
+        significand128.parts[2] = midl;
+        significand128.parts[3] = low;
+ 
+        if (significand128.parts[0] == 0 && significand128.parts[1] == 0 &&
+            significand128.parts[2] == 0 && significand128.parts[3] == 0) {
+           is_zero = true;
+        } else if (significand128.parts[0] >= (1 << 17)) {
+           /* The significand is non-canonical or zero.
+            * In order to preserve compatibility with the densely packed decimal
+            * format, the maximum value for the significand of decimal128 is
+            * 1e34 - 1.  If the value is greater than 1e34 - 1, the IEEE 754
+            * standard dictates that the significand is interpreted as zero.
+            */
+           is_zero = true;
+        } else {
+           for (int k = 3; k >= 0; k--) {
+              uint32_t least_digits = 0;
+              detail::bson_uint128_divide1B (
+                 significand128, &significand128, &least_digits);
+ 
+              /* We now have the 9 least significant digits (in base 2). */
+              /* Convert and output to string. */
+              if (!least_digits) {
+                 continue;
+              }
+ 
+              for (int j = 8; j >= 0; j--) {
+                 significand[k * 9 + j] = least_digits % 10;
+                 least_digits /= 10;
+              }
+           }
+        }
+ 
+        /* Output format options: */
+        /* Scientific - [-]d.dddE(+/-)dd or [-]dE(+/-)dd */
+        /* Regular    - ddd.ddd */
+ 
+        if (is_zero) {
+           significand_digits = 1;
+           *significand_read = 0;
+        } else {
+           significand_digits = 36;
+           while (!(*significand_read)) {
+              significand_digits--;
+              significand_read++;
+           }
+        }
+ 
+        scientific_exponent = significand_digits - 1 + exponent;
+ 
+        /* The scientific exponent checks are dictated by the string conversion
+         * specification and are somewhat arbitrary cutoffs.
+         *
+         * We must check exponent > 0, because if this is the case, the number
+         * has trailing zeros.  However, we *cannot* output these trailing zeros,
+         * because doing so would change the precision of the value, and would
+         * change stored data if the string converted number is round tripped.
+         */
+        if (scientific_exponent < -6 || exponent > 0) {
+           /* Scientific format */
+           *(str_out++) = char(*(significand_read++)) + '0';
+           significand_digits--;
+ 
+           if (significand_digits) {
+              *(str_out++) = '.';
+           }
+ 
+           for (std::size_t i = 0; i < significand_digits && (str_out - first) < 36; i++) {
+              *(str_out++) = char(*(significand_read++)) + '0';
+           }
+           /* Exponent */
+           *(str_out++) = 'E';
+
+           std::string s;
+           if (scientific_exponent >= 0) {
+               s.push_back('+');
+           }
+           jsoncons::detail::from_integer(scientific_exponent, s);
+           if (str_out + s.size() < last) 
+           {
+               std::memcpy(str_out, s.data(), s.size());
+           }
+           else
+           {
+               return decimal128_to_chars_result{str_out, std::errc::value_too_large};
+           }
+           str_out += s.size();
+        } else {
+           /* Regular format with no decimal place */
+           if (exponent >= 0) {
+              for (std::size_t i = 0; i < significand_digits && (str_out - first) < 36; i++) {
+                 *(str_out++) = char(*(significand_read++)) + '0';
+              }
+           } else {
+              int32_t radix_position = significand_digits + exponent;
+ 
+              if (radix_position > 0) { /* non-zero digits before radix */
+                 for (int32_t i = 0;
+                      i < radix_position && (str_out < last);
+                      i++) {
+                    *(str_out++) = char(*(significand_read++)) + '0';
+                 }
+              } else { /* leading zero before radix point */
+                 *(str_out++) = '0';
+              }
+ 
+              *(str_out++) = '.';
+              while (radix_position++ < 0) { /* add leading zeros after radix */
+                 *(str_out++) = '0';
+              }
+ 
+              for (std::size_t i = 0;
+                   (i < significand_digits - (std::max) (radix_position - 1, 0)) &&
+                   (str_out < last);
+                   i++) {
+                 *(str_out++) = char(*(significand_read++)) + '0';
+              }
+           }
+        }
+        return decimal128_to_chars_result{str_out, std::errc()};
+    }
+
+
+
+    /**
+     *------------------------------------------------------------------------------
+     *
+     * bson_decimal128_from_string_w_len --
+     *
+     *    This function converts @string in the format [+-]ddd[.]ddd[E][+-]dddd to
+     *    decimal128.  Out of range values are converted to +/-Infinity.  Invalid
+     *    strings are converted to NaN. @len is the length of the string, or -1
+     *    meaning the string is null-terminated.
+     *
+     *    If more digits are provided than the available precision allows,
+     *    round to the nearest expressable decimal128 with ties going to even will
+     *    occur.
+     *
+     *    Note: @string must be ASCII only!
+     *
+     * Returns:
+     *    true on success, or false on failure. @dec will be NaN if @str was invalid
+     *    The &decimal128_t converted from @string at @dec.
+     *
+     * Side effects:
+     *    None.
+     *
+     *------------------------------------------------------------------------------
+     */
+
+    inline
+    decimal128_from_chars_result decimal128_from_chars(const char* first, const char* last, decimal128_t& dec) 
+    {
+        const string_view inf_str = "inf";
+        const string_view infinity_str = "infinity";
+        const string_view nan_str = "nan";
+
+        ptrdiff_t len = last - first;
+
+        bson_uint128_6464_t significand = {0,0};
+ 
+        const char* str_read = first; /* Read pointer for consuming str. */
+ 
+        /* Parsing state tracking */
+        bool is_negative = false;
+        bool saw_radix = false;
+        bool includes_sign = false; /* True if the input first contains a sign. */
+        bool found_nonzero = false;
+ 
+        size_t significant_digits = 0; /* Total number of significant digits
+                                        * (no leading or trailing zero) */
+        size_t ndigits_read = 0;       /* Total number of significand digits read */
+        size_t ndigits = 0;        /* Total number of digits (no leading zeros) */
+        size_t radix_position = 0; /* The number of the digits after radix */
+        size_t first_nonzero = 0;  /* The index of the first non-zero in *str* */
+ 
+        uint16_t digits[decimal128_limits::max_digits] = {0};
+        uint16_t ndigits_stored = 0;      /* The number of digits in digits */
+        uint16_t *digits_insert = digits; /* Insertion pointer for digits */
+        size_t first_digit = 0;           /* The index of the first non-zero digit */
+        size_t last_digit = 0;            /* The index of the last digit */
+ 
+        int32_t exponent = 0;
+        uint64_t significand_high = 0; /* The high 17 digits of the significand */
+        uint64_t significand_low = 0;  /* The low 17 digits of the significand */
+        uint16_t biased_exponent = 0;  /* The biased exponent */
+ 
+        dec.high = 0;
+        dec.low = 0;
+ 
+        if (*str_read == '+' || *str_read == '-') {
+           is_negative = *(str_read++) == '-';
+           includes_sign = true;
+        }
+
+        /* Check for Infinity or NaN */
+        if (!isdigit (*str_read) && *str_read != '.') {
+           if (detail::dec128_istreq (str_read, last, inf_str.data(), inf_str.data()+inf_str.length()) ||
+               detail::dec128_istreq (str_read, last, infinity_str.data(), infinity_str.data()+infinity_str.length())) 
+           {
+               dec = is_negative ? decimal128_limits::neg_infinity() : decimal128_limits::infinity();
+              return decimal128_from_chars_result{str_read,std::errc()};
+           } else if (detail::dec128_istreq (str_read, last, nan_str.data(), nan_str.data()+nan_str.length())) {
+              dec = decimal128_limits::nan();
+              return decimal128_from_chars_result{str_read,std::errc()};
+           }
+ 
+           dec = decimal128_limits::nan();
+           return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+        }
+ 
+        /* Read digits */
+        while (((isdigit (*str_read) || *str_read == '.')) &&
+               (len == -1 || str_read < first + len)) {
+           if (*str_read == '.') {
+              if (saw_radix) {
+                 dec = decimal128_limits::nan();
+                 return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+              }
+ 
+              saw_radix = true;
+              str_read++;
+              continue;
+           }
+ 
+           if (ndigits_stored < 34) {
+              if (*str_read != '0' || found_nonzero) {
+                 if (!found_nonzero) {
+                    first_nonzero = ndigits_read;
+                 }
+ 
+                 found_nonzero = true;
+                 *(digits_insert++) = *(str_read) - '0'; /* Only store 34 digits */
+                 ndigits_stored++;
+              }
+           }
+ 
+           if (found_nonzero) {
+              ndigits++;
+           }
+ 
+           if (saw_radix) {
+              radix_position++;
+           }
+ 
+           ndigits_read++;
+           str_read++;
+        }
+ 
+        if (saw_radix && !ndigits_read) {
+           dec = decimal128_limits::nan();
+           return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+        }
+ 
+        /* Read exponent if exists */
+        if (*str_read == 'e' || *str_read == 'E') {
+           ++str_read;
+           if (*str_read == '+') {
+               ++str_read;
+           }
+           auto result = jsoncons::detail::to_integer(str_read, last - str_read, exponent);
+           if (result.ec != jsoncons::detail::to_integer_errc()) 
+           {
+               dec = decimal128_limits::nan();
+               return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+           }
+           str_read = result.ptr;
+        }
+
+        if ((len == -1 || str_read < first + len) && *str_read) {
+           dec = decimal128_limits::nan();
+           return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+        }
+ 
+        /* Done reading input. */
+        /* Find first non-zero digit in digits */
+        first_digit = 0;
+ 
+        if (!ndigits_stored) { /* value is zero */
+           first_digit = 0;
+           last_digit = 0;
+           digits[0] = 0;
+           ndigits = 1;
+           ndigits_stored = 1;
+           significant_digits = 0;
+        } else {
+           last_digit = ndigits_stored - 1;
+           significant_digits = ndigits;
+           /* Mark trailing zeros as non-significant */
+           while (first[first_nonzero + significant_digits - 1 + includes_sign +
+                         saw_radix] == '0') {
+              significant_digits--;
+           }
+        }
+ 
+ 
+        /* Normalization of exponent */
+        /* Correct exponent based on radix position, and shift significand as needed
+         */
+        /* to represent user input */
+ 
+        /* Overflow prevention */
+        if (exponent <= static_cast<int32_t>(radix_position) && static_cast<int32_t>(radix_position) - exponent > (1 << 14)) {
+           exponent = decimal128_limits::exponent_min;
+        } else {
+           exponent -= static_cast<int32_t>(radix_position);
+        }
+ 
+        /* Attempt to normalize the exponent */
+        while (exponent > decimal128_limits::exponent_max) {
+           /* Shift exponent to significand and decrease */
+           last_digit++;
+ 
+           if (last_digit - first_digit > decimal128_limits::max_digits) {
+              /* The exponent is too great to shift into the significand. */
+              if (significant_digits == 0) {
+                 /* Value is zero, we are allowed to clamp the exponent. */
+                 exponent = decimal128_limits::exponent_max;
+                 break;
+              }
+ 
+              /* Overflow is not permitted, error. */
+              dec = decimal128_limits::nan();
+              return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+           }
+ 
+           exponent--;
+        }
+ 
+        while (exponent < decimal128_limits::exponent_min || ndigits_stored < ndigits) {
+           /* Shift last digit */
+           if (last_digit == 0) {
+              /* underflow is not allowed, but zero clamping is */
+              if (significant_digits == 0) {
+                 exponent = decimal128_limits::exponent_min;
+                 break;
+              }
+ 
+              dec = decimal128_limits::nan();
+              return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+           }
+ 
+           if (ndigits_stored < ndigits) {
+              if (first[ndigits - 1 + includes_sign + saw_radix] - '0' != 0 &&
+                  significant_digits != 0) {
+                 dec = decimal128_limits::nan();
+                 return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+              }
+ 
+              ndigits--; /* adjust to match digits not stored */
+           } else {
+              if (digits[last_digit] != 0) {
+                 /* Inexact rounding is not allowed. */
+                 dec = decimal128_limits::nan();
+                 return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+              }
+ 
+ 
+              last_digit--; /* adjust to round */
+           }
+ 
+           if (exponent < decimal128_limits::exponent_max) {
+              exponent++;
+           } else {
+              dec = decimal128_limits::nan();
+              return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+           }
+        }
+ 
+        /* Round */
+        /* We've normalized the exponent, but might still need to round. */
+        if (last_digit - first_digit + 1 < significant_digits) {
+           uint8_t round_digit;
+ 
+           /* There are non-zero digits after last_digit that need rounding. */
+           /* We round to nearest, ties to even */
+           round_digit =
+              first[first_nonzero + last_digit + includes_sign + saw_radix + 1] -
+              '0';
+ 
+           if (round_digit != 0) {
+              /* Inexact (non-zero) rounding is not allowed */
+              dec = decimal128_limits::nan();
+              return decimal128_from_chars_result{str_read,std::errc::invalid_argument};
+           }
+        }
+ 
+        /* Encode significand */
+        significand_high = 0,   /* The high 17 digits of the significand */
+           significand_low = 0; /* The low 17 digits of the significand */
+ 
+        if (significant_digits == 0) { /* read a zero */
+           significand_high = 0;
+           significand_low = 0;
+        } else if (last_digit - first_digit < 17) {
+           size_t d_idx = first_digit;
+           significand_low = digits[d_idx++];
+ 
+           for (; d_idx <= last_digit; d_idx++) {
+              significand_low *= 10;
+              significand_low += digits[d_idx];
+              significand_high = 0;
+           }
+        } else {
+           size_t d_idx = first_digit;
+           significand_high = digits[d_idx++];
+ 
+           for (; d_idx <= last_digit - 17; d_idx++) {
+              significand_high *= 10;
+              significand_high += digits[d_idx];
+           }
+ 
+           significand_low = digits[d_idx++];
+ 
+           for (; d_idx <= last_digit; d_idx++) {
+              significand_low *= 10;
+              significand_low += digits[d_idx];
+           }
+        }
+ 
+        detail::mul_64x64 (significand_high, 100000000000000000ull, &significand);
+        significand.low += significand_low;
+ 
+        if (significand.low < significand_low) {
+           significand.high += 1;
+        }
+ 
+ 
+        biased_exponent = static_cast<uint16_t>(exponent + static_cast<int32_t>(decimal128_limits::exponent_bias));
+ 
+        /* Encode combination, exponent, and significand. */
+        if ((significand.high >> 49) & 1) {
+           /* Encode '11' into bits 1 to 3 */
+           dec.high |= (0x3ull << 61);
+           dec.high |= (biased_exponent & 0x3fffull) << 47;
+           dec.high |= significand.high & 0x7fffffffffffull;
+        } else {
+           dec.high |= (biased_exponent & 0x3fffull) << 49;
+           dec.high |= significand.high & 0x1ffffffffffffull;
+        }
+ 
+        dec.low = significand.low;
+ 
+        /* Encode sign */
+        if (is_negative) {
+           dec.high |= 0x8000000000000000ull;
+        }
+ 
+        return decimal128_from_chars_result{str_read,std::errc()};
+    }
+
+} // namespace bson
+} // namespace jsoncons
+
+#endif
diff --git a/include/jsoncons_ext/bson/bson_decimal128.hpp.bak b/include/jsoncons_ext/bson/bson_decimal128.hpp.bak
new file mode 100644
index 0000000..8e27ee1
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_decimal128.hpp.bak
@@ -0,0 +1,816 @@
+#ifndef JSONCONS_BSON_BSON_DECIMAL128_HPP
+#define JSONCONS_BSON_BSON_DECIMAL128_HPP
+
+/*
+ * Copyright 2015 MongoDB, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <system_error>
+#include <jsoncons/config/jsoncons_config.hpp>
+
+namespace jsoncons { namespace bson {
+
+    struct decimal128_to_chars_result 
+    {
+        char* ptr;
+        std::errc ec;
+    };
+
+    struct decimal128_from_chars_result 
+    {
+        const char* ptr;
+        std::errc ec;
+    };
+
+/**
+ * BSON_DECIMAL128_STRING:
+ *
+ * The length of a decimal128 string (with null terminator).
+ *
+ * 1  for the sign
+ * 35 for digits and radix
+ * 2  for exponent indicator and sign
+ * 4  for exponent digits
+ */
+#define BSON_DECIMAL128_STRING 43
+#define BSON_DECIMAL128_INF "Infinity"
+#define BSON_DECIMAL128_NAN "NaN"
+
+    struct TP1 
+    { 
+        uint64_t low; 
+        uint64_t high; 
+
+        constexpr TP1() : low(0), high(0) {}
+        constexpr TP1(uint64_t hi, uint64_t lo) : low(lo), high(hi) {}
+    };
+    struct TP2 
+    { 
+        uint64_t high; 
+        uint64_t low; 
+
+        constexpr TP2() : high(0), low(0) {}
+        constexpr TP2(uint64_t hi, uint64_t lo) : high(hi), low(lo) {}
+    };
+
+    typedef typename std::conditional<
+        jsoncons::endian::native == jsoncons::endian::little,
+        TP1,
+        TP2
+    >::type decimal128_t;
+
+    inline
+    bool operator==(const decimal128_t& lhs, const decimal128_t& rhs)
+    {
+       return lhs.high == rhs.high && lhs.low == rhs.low;
+    }   
+
+    inline
+    bool operator!=(const decimal128_t& lhs, const decimal128_t& rhs)
+    {
+       return !(lhs == rhs);
+    }   
+
+    struct decimal128_limits
+    {
+        // The length of a decimal128 string (without null terminator).
+        //
+        // 1  for the sign
+        // 35 for digits and radix
+        // 2  for exponent indicator and sign
+        // 4  for exponent digits
+        static constexpr int recommended_buffer_size = 42;  
+        static constexpr decimal128_t nan = decimal128_t(0x7c00000000000000ull, 0);
+        static constexpr decimal128_t infinity = decimal128_t(0x7800000000000000ull, 0);
+        static constexpr decimal128_t neg_infinity = decimal128_t(0x7800000000000000ull + 0x8000000000000000ull, 0);
+        static constexpr int exponent_max = 6111;
+        static constexpr int exponent_min = -6176;
+        static constexpr int exponent_bias = 6176;
+        static constexpr int max_digits = 34;
+    };
+
+    /**
+     * bson_uint128_t:
+     *
+     * This struct represents a 128 bit integer.
+     */
+    typedef struct {
+       uint32_t parts[4]; /* 32-bit words stored high to low. */
+    } bson_uint128_t;
+
+    typedef struct {
+       uint64_t high, low;
+    } bson_uint128_6464_t;
+
+    namespace detail {
+    
+        /**
+         *------------------------------------------------------------------------------
+         *
+         * bson_uint128_divide1B --
+         *
+         *    This function divides a #bson_uint128_t by 1000000000 (1 billion) and
+         *    computes the quotient and remainder.
+         *
+         *    The remainder will contain 9 decimal digits for conversion to string.
+         *
+         * @value     The #bson_uint128_t operand.
+         * @quotient  A pointer to store the #bson_uint128_t quotient.
+         * @rem       A pointer to store the #uint64_t remainder.
+         *
+         * Returns:
+         *    The quotient at @quotient and the remainder at @rem.
+         *
+         * Side effects:
+         *    None.
+         *
+         *------------------------------------------------------------------------------
+         */
+
+        inline
+        void bson_uint128_divide1B (bson_uint128_t value,     /* IN */
+                                     bson_uint128_t *quotient, /* OUT */
+                                     uint32_t *rem)             /* OUT */
+        {
+           const uint32_t DIVISOR = 1000 * 1000 * 1000;
+           uint64_t _rem = 0;
+           int i = 0;
+
+           if (!value.parts[0] && !value.parts[1] && !value.parts[2] &&
+               !value.parts[3]) {
+              *quotient = value;
+              *rem = 0;
+              return;
+           }
+
+           for (i = 0; i <= 3; i++) {
+              _rem <<= 32; /* Adjust remainder to match value of next dividend */
+              _rem += value.parts[i]; /* Add the divided to _rem */
+              value.parts[i] = (uint32_t) (_rem / DIVISOR);
+              _rem %= DIVISOR; /* Store the remainder */
+           }
+
+           *quotient = value;
+           *rem = (uint32_t) _rem;
+        }
+
+        /**
+         *-------------------------------------------------------------------------
+         *
+         * mul64x64 --
+         *
+         *    This function multiplies two &uint64_t into a &bson_uint128_6464_t.
+         *
+         * Returns:
+         *    The product of @left and @right.
+         *
+         * Side Effects:
+         *    None.
+         *
+         *-------------------------------------------------------------------------
+         */
+
+        inline
+        void mul_64x64 (uint64_t left,                 /* IN */
+                        uint64_t right,                /* IN */
+                        bson_uint128_6464_t *product) /* OUT */
+        {
+           uint64_t left_high, left_low, right_high, right_low, product_high,
+              product_mid, product_mid2, product_low;
+           bson_uint128_6464_t rt = {0};
+
+           if (!left && !right) {
+              *product = rt;
+              return;
+           }
+
+           left_high = left >> 32;
+           left_low = (uint32_t) left;
+           right_high = right >> 32;
+           right_low = (uint32_t) right;
+
+           product_high = left_high * right_high;
+           product_mid = left_high * right_low;
+           product_mid2 = left_low * right_high;
+           product_low = left_low * right_low;
+
+           product_high += product_mid >> 32;
+           product_mid = (uint32_t) product_mid + product_mid2 + (product_low >> 32);
+
+           product_high = product_high + (product_mid >> 32);
+           product_low = (product_mid << 32) + (uint32_t) product_low;
+
+           rt.high = product_high;
+           rt.low = product_low;
+           *product = rt;
+        }
+
+        /**
+         *------------------------------------------------------------------------------
+         *
+         * dec128_tolower --
+         *
+         *    This function converts the ASCII character @c to lowercase.  It is locale
+         *    insensitive (unlike the stdlib tolower).
+         *
+         * Returns:
+         *    The lowercased character.
+         */
+
+        inline
+        char dec128_tolower (char c)
+        {
+           if (isupper (c)) {
+              c += 32;
+           }
+
+           return c;
+        }
+
+        /**
+         *------------------------------------------------------------------------------
+         *
+         * dec128_istreq --
+         *
+         *    This function compares the null-terminated *ASCII* strings @a and @b
+         *    for case-insensitive equality.
+         *
+         * Returns:
+         *    true if the strings are equal, false otherwise.
+         */
+
+        inline
+        bool dec128_istreq (const char* a, /* IN */
+                        const char* b /* IN */)
+        {
+           while (*a != '\0' || *b != '\0') {
+              /* strings are different lengths. */
+              if (*a == '\0' || *b == '\0') {
+                 return false;
+              }
+
+              if (dec128_tolower (*a) != dec128_tolower (*b)) {
+                 return false;
+              }
+
+              a++;
+              b++;
+           }
+
+           return true;
+        }
+
+    } // namespace detail
+
+
+    /**
+     *------------------------------------------------------------------------------
+     *
+     * decimal128_to_chars --
+     *
+     *    This function converts a BID formatted decimal128 value to string,
+     *    accepting a &decimal128_t as @dec.  The string is stored at @str.
+     *
+     * @dec : The BID formatted decimal to convert.
+     * @str : The output decimal128 string. At least %BSON_DECIMAL128_STRING
+     *characters.
+     *
+     * Returns:
+     *    None.
+     *
+     * Side effects:
+     *    None.
+     *
+     *------------------------------------------------------------------------------
+     */
+
+    inline
+    void decimal128_to_chars(char* first, char* last, const decimal128_t& dec)
+    {
+       uint32_t COMBINATION_MASK = 0x1f;   /* Extract least significant 5 bits */
+       uint32_t EXPONENT_MASK = 0x3fff;    /* Extract least significant 14 bits */
+       uint32_t COMBINATION_INFINITY = 30; /* Value of combination field for Inf */
+       uint32_t COMBINATION_NAN = 31;      /* Value of combination field for NaN */
+       uint32_t EXPONENT_BIAS = 6176;      /* decimal128 exponent bias */
+
+       char* str_out = first;      /* output pointer in string */
+       char significand_str[35]; /* decoded significand digits */
+
+
+       /* Note: bits in this routine are referred to starting at 0, */
+       /* from the sign bit, towards the coefficient. */
+       uint32_t high;                   /* bits 0 - 31 */
+       uint32_t midh;                   /* bits 32 - 63 */
+       uint32_t midl;                   /* bits 64 - 95 */
+       uint32_t low;                    /* bits 96 - 127 */
+       uint32_t combination;            /* bits 1 - 5 */
+       uint32_t biased_exponent;        /* decoded biased exponent (14 bits) */
+       uint32_t significand_digits = 0; /* the number of significand digits */
+       uint32_t significand[36] = {0};  /* the base-10 digits in the significand */
+       uint32_t *significand_read = significand; /* read pointer into significand */
+       int32_t exponent;                         /* unbiased exponent */
+       int32_t scientific_exponent; /* the exponent if scientific notation is
+                                     * used */
+       bool is_zero = false;        /* true if the number is zero */
+
+       uint8_t significand_msb; /* the most signifcant significand bits (50-46) */
+       bson_uint128_t
+          significand128; /* temporary storage for significand decoding */
+       size_t i;          /* indexing variables */
+       int j, k;
+
+       memset (significand_str, 0, sizeof (significand_str));
+
+       if ((int64_t) dec.high < 0) { /* negative */
+          *(str_out++) = '-';
+       }
+
+       low = (uint32_t) dec.low, midl = (uint32_t) (dec.low >> 32),
+       midh = (uint32_t) dec.high, high = (uint32_t) (dec.high >> 32);
+
+       /* Decode combination field and exponent */
+       combination = (high >> 26) & COMBINATION_MASK;
+
+       if (JSONCONS_UNLIKELY ((combination >> 3) == 3)) {
+          /* Check for 'special' values */
+          if (combination == COMBINATION_INFINITY) { /* Infinity */
+             strcpy (str_out, BSON_DECIMAL128_INF);
+             return;
+          } else if (combination == COMBINATION_NAN) { /* NaN */
+             /* first, not str_out, to erase the sign */
+             strcpy (first, BSON_DECIMAL128_NAN);
+             /* we don't care about the NaN payload. */
+             return;
+          } else {
+             biased_exponent = (high >> 15) & EXPONENT_MASK;
+             significand_msb = 0x8 + ((high >> 14) & 0x1);
+          }
+       } else {
+          significand_msb = (high >> 14) & 0x7;
+          biased_exponent = (high >> 17) & EXPONENT_MASK;
+       }
+
+       exponent = biased_exponent - EXPONENT_BIAS;
+       /* Create string of significand digits */
+
+       /* Convert the 114-bit binary number represented by */
+       /* (high, midh, midl, low) to at most 34 decimal */
+       /* digits through modulo and division. */
+       significand128.parts[0] = (high & 0x3fff) + ((significand_msb & 0xf) << 14);
+       significand128.parts[1] = midh;
+       significand128.parts[2] = midl;
+       significand128.parts[3] = low;
+
+       if (significand128.parts[0] == 0 && significand128.parts[1] == 0 &&
+           significand128.parts[2] == 0 && significand128.parts[3] == 0) {
+          is_zero = true;
+       } else if (significand128.parts[0] >= (1 << 17)) {
+          /* The significand is non-canonical or zero.
+           * In order to preserve compatibility with the densely packed decimal
+           * format, the maximum value for the significand of decimal128 is
+           * 1e34 - 1.  If the value is greater than 1e34 - 1, the IEEE 754
+           * standard dictates that the significand is interpreted as zero.
+           */
+          is_zero = true;
+       } else {
+          for (k = 3; k >= 0; k--) {
+             uint32_t least_digits = 0;
+             detail::bson_uint128_divide1B (
+                significand128, &significand128, &least_digits);
+
+             /* We now have the 9 least significant digits (in base 2). */
+             /* Convert and output to string. */
+             if (!least_digits) {
+                continue;
+             }
+
+             for (j = 8; j >= 0; j--) {
+                significand[k * 9 + j] = least_digits % 10;
+                least_digits /= 10;
+             }
+          }
+       }
+
+       /* Output format options: */
+       /* Scientific - [-]d.dddE(+/-)dd or [-]dE(+/-)dd */
+       /* Regular    - ddd.ddd */
+
+       if (is_zero) {
+          significand_digits = 1;
+          *significand_read = 0;
+       } else {
+          significand_digits = 36;
+          while (!(*significand_read)) {
+             significand_digits--;
+             significand_read++;
+          }
+       }
+
+       scientific_exponent = significand_digits - 1 + exponent;
+
+       /* The scientific exponent checks are dictated by the string conversion
+        * specification and are somewhat arbitrary cutoffs.
+        *
+        * We must check exponent > 0, because if this is the case, the number
+        * has trailing zeros.  However, we *cannot* output these trailing zeros,
+        * because doing so would change the precision of the value, and would
+        * change stored data if the string converted number is round tripped.
+        */
+       if (scientific_exponent < -6 || exponent > 0) {
+          /* Scientific format */
+          *(str_out++) = *(significand_read++) + '0';
+          significand_digits--;
+
+          if (significand_digits) {
+             *(str_out++) = '.';
+          }
+
+          for (i = 0; i < significand_digits && (str_out - first) < 36; i++) {
+             *(str_out++) = *(significand_read++) + '0';
+          }
+          /* Exponent */
+          *(str_out++) = 'E';
+          snprintf (str_out, 6, "%+d", scientific_exponent);
+       } else {
+          /* Regular format with no decimal place */
+          if (exponent >= 0) {
+             for (i = 0; i < significand_digits && (str_out - first) < 36; i++) {
+                *(str_out++) = *(significand_read++) + '0';
+             }
+             *str_out = '\0';
+          } else {
+             int32_t radix_position = significand_digits + exponent;
+
+             if (radix_position > 0) { /* non-zero digits before radix */
+                for (i = 0;
+                     i < radix_position && (str_out < last);
+                     i++) {
+                   *(str_out++) = *(significand_read++) + '0';
+                }
+             } else { /* leading zero before radix point */
+                *(str_out++) = '0';
+             }
+
+             *(str_out++) = '.';
+             while (radix_position++ < 0) { /* add leading zeros after radix */
+                *(str_out++) = '0';
+             }
+
+             for (i = 0;
+                  (i < significand_digits - (std::max) (radix_position - 1, 0)) &&
+                  (str_out < last);
+                  i++) {
+                *(str_out++) = *(significand_read++) + '0';
+             }
+             *str_out = '\0';
+          }
+       }
+    }
+
+
+
+    /**
+     *------------------------------------------------------------------------------
+     *
+     * bson_decimal128_from_string_w_len --
+     *
+     *    This function converts @string in the format [+-]ddd[.]ddd[E][+-]dddd to
+     *    decimal128.  Out of range values are converted to +/-Infinity.  Invalid
+     *    strings are converted to NaN. @len is the length of the string, or -1
+     *    meaning the string is null-terminated.
+     *
+     *    If more digits are provided than the available precision allows,
+     *    round to the nearest expressable decimal128 with ties going to even will
+     *    occur.
+     *
+     *    Note: @string must be ASCII only!
+     *
+     * Returns:
+     *    true on success, or false on failure. @dec will be NaN if @str was invalid
+     *    The &decimal128_t converted from @string at @dec.
+     *
+     * Side effects:
+     *    None.
+     *
+     *------------------------------------------------------------------------------
+     */
+
+    inline
+    bool decimal128_from_chars(const char* first, const char* last, decimal128_t& dec) 
+    {
+        int len = last - first;
+
+       bson_uint128_6464_t significand = {0};
+
+       const char* str_read = first; /* Read pointer for consuming str. */
+
+       /* Parsing state tracking */
+       bool is_negative = false;
+       bool saw_radix = false;
+       bool includes_sign = false; /* True if the input first contains a sign. */
+       bool found_nonzero = false;
+
+       size_t significant_digits = 0; /* Total number of significant digits
+                                       * (no leading or trailing zero) */
+       size_t ndigits_read = 0;       /* Total number of significand digits read */
+       size_t ndigits = 0;        /* Total number of digits (no leading zeros) */
+       size_t radix_position = 0; /* The number of the digits after radix */
+       size_t first_nonzero = 0;  /* The index of the first non-zero in *str* */
+
+       uint16_t digits[decimal128_limits::max_digits] = {0};
+       uint16_t ndigits_stored = 0;      /* The number of digits in digits */
+       uint16_t *digits_insert = digits; /* Insertion pointer for digits */
+       size_t first_digit = 0;           /* The index of the first non-zero digit */
+       size_t last_digit = 0;            /* The index of the last digit */
+
+       int32_t exponent = 0;
+       uint64_t significand_high = 0; /* The high 17 digits of the significand */
+       uint64_t significand_low = 0;  /* The low 17 digits of the significand */
+       uint16_t biased_exponent = 0;  /* The biased exponent */
+
+       dec.high = 0;
+       dec.low = 0;
+
+       if (*str_read == '+' || *str_read == '-') {
+          is_negative = *(str_read++) == '-';
+          includes_sign = true;
+       }
+
+       /* Check for Infinity or NaN */
+       if (!isdigit (*str_read) && *str_read != '.') {
+          if (detail::dec128_istreq (str_read, "inf") ||
+              detail::dec128_istreq (str_read, "infinity")) {
+              dec = is_negative ? decimal128_limits::neg_infinity : decimal128_limits::infinity;
+             return true;
+          } else if (detail::dec128_istreq (str_read, "nan")) {
+             dec = decimal128_limits::nan;
+             return true;
+          }
+
+          dec = decimal128_limits::nan;
+          return false;
+       }
+
+       /* Read digits */
+       while (((isdigit (*str_read) || *str_read == '.')) &&
+              (len == -1 || str_read < first + len)) {
+          if (*str_read == '.') {
+             if (saw_radix) {
+                dec = decimal128_limits::nan;
+                return false;
+             }
+
+             saw_radix = true;
+             str_read++;
+             continue;
+          }
+
+          if (ndigits_stored < 34) {
+             if (*str_read != '0' || found_nonzero) {
+                if (!found_nonzero) {
+                   first_nonzero = ndigits_read;
+                }
+
+                found_nonzero = true;
+                *(digits_insert++) = *(str_read) - '0'; /* Only store 34 digits */
+                ndigits_stored++;
+             }
+          }
+
+          if (found_nonzero) {
+             ndigits++;
+          }
+
+          if (saw_radix) {
+             radix_position++;
+          }
+
+          ndigits_read++;
+          str_read++;
+       }
+
+       if (saw_radix && !ndigits_read) {
+          dec = decimal128_limits::nan;
+          return false;
+       }
+
+       /* Read exponent if exists */
+       if (*str_read == 'e' || *str_read == 'E') {
+          int nread = 0;
+    #ifdef _MSC_VER
+    #define SSCANF sscanf_s
+    #else
+    #define SSCANF sscanf
+    #endif
+          int read_exponent = SSCANF (++str_read, "%d%n", &exponent, &nread);
+          str_read += nread;
+
+          if (!read_exponent || nread == 0) {
+             dec = decimal128_limits::nan;
+             return false;
+          }
+
+    #undef SSCANF
+       }
+
+       if ((len == -1 || str_read < first + len) && *str_read) {
+          dec = decimal128_limits::nan;
+          return false;
+       }
+
+       /* Done reading input. */
+       /* Find first non-zero digit in digits */
+       first_digit = 0;
+
+       if (!ndigits_stored) { /* value is zero */
+          first_digit = 0;
+          last_digit = 0;
+          digits[0] = 0;
+          ndigits = 1;
+          ndigits_stored = 1;
+          significant_digits = 0;
+       } else {
+          last_digit = ndigits_stored - 1;
+          significant_digits = ndigits;
+          /* Mark trailing zeros as non-significant */
+          while (first[first_nonzero + significant_digits - 1 + includes_sign +
+                        saw_radix] == '0') {
+             significant_digits--;
+          }
+       }
+
+
+       /* Normalization of exponent */
+       /* Correct exponent based on radix position, and shift significand as needed
+        */
+       /* to represent user input */
+
+       /* Overflow prevention */
+       if (exponent <= radix_position && radix_position - exponent > (1 << 14)) {
+          exponent = decimal128_limits::exponent_min;
+       } else {
+          exponent -= radix_position;
+       }
+
+       /* Attempt to normalize the exponent */
+       while (exponent > decimal128_limits::exponent_max) {
+          /* Shift exponent to significand and decrease */
+          last_digit++;
+
+          if (last_digit - first_digit > decimal128_limits::max_digits) {
+             /* The exponent is too great to shift into the significand. */
+             if (significant_digits == 0) {
+                /* Value is zero, we are allowed to clamp the exponent. */
+                exponent = decimal128_limits::exponent_max;
+                break;
+             }
+
+             /* Overflow is not permitted, error. */
+             dec = decimal128_limits::nan;
+             return false;
+          }
+
+          exponent--;
+       }
+
+       while (exponent < decimal128_limits::exponent_min || ndigits_stored < ndigits) {
+          /* Shift last digit */
+          if (last_digit == 0) {
+             /* underflow is not allowed, but zero clamping is */
+             if (significant_digits == 0) {
+                exponent = decimal128_limits::exponent_min;
+                break;
+             }
+
+             dec = decimal128_limits::nan;
+             return false;
+          }
+
+          if (ndigits_stored < ndigits) {
+             if (first[ndigits - 1 + includes_sign + saw_radix] - '0' != 0 &&
+                 significant_digits != 0) {
+                dec = decimal128_limits::nan;
+                return false;
+             }
+
+             ndigits--; /* adjust to match digits not stored */
+          } else {
+             if (digits[last_digit] != 0) {
+                /* Inexact rounding is not allowed. */
+                dec = decimal128_limits::nan;
+                return false;
+             }
+
+
+             last_digit--; /* adjust to round */
+          }
+
+          if (exponent < decimal128_limits::exponent_max) {
+             exponent++;
+          } else {
+             dec = decimal128_limits::nan;
+             return false;
+          }
+       }
+
+       /* Round */
+       /* We've normalized the exponent, but might still need to round. */
+       if (last_digit - first_digit + 1 < significant_digits) {
+          uint8_t round_digit;
+
+          /* There are non-zero digits after last_digit that need rounding. */
+          /* We round to nearest, ties to even */
+          round_digit =
+             first[first_nonzero + last_digit + includes_sign + saw_radix + 1] -
+             '0';
+
+          if (round_digit != 0) {
+             /* Inexact (non-zero) rounding is not allowed */
+             dec = decimal128_limits::nan;
+             return false;
+          }
+       }
+
+       /* Encode significand */
+       significand_high = 0,   /* The high 17 digits of the significand */
+          significand_low = 0; /* The low 17 digits of the significand */
+
+       if (significant_digits == 0) { /* read a zero */
+          significand_high = 0;
+          significand_low = 0;
+       } else if (last_digit - first_digit < 17) {
+          size_t d_idx = first_digit;
+          significand_low = digits[d_idx++];
+
+          for (; d_idx <= last_digit; d_idx++) {
+             significand_low *= 10;
+             significand_low += digits[d_idx];
+             significand_high = 0;
+          }
+       } else {
+          size_t d_idx = first_digit;
+          significand_high = digits[d_idx++];
+
+          for (; d_idx <= last_digit - 17; d_idx++) {
+             significand_high *= 10;
+             significand_high += digits[d_idx];
+          }
+
+          significand_low = digits[d_idx++];
+
+          for (; d_idx <= last_digit; d_idx++) {
+             significand_low *= 10;
+             significand_low += digits[d_idx];
+          }
+       }
+
+       detail::mul_64x64 (significand_high, 100000000000000000ull, &significand);
+       significand.low += significand_low;
+
+       if (significand.low < significand_low) {
+          significand.high += 1;
+       }
+
+
+       biased_exponent = (exponent + (int16_t) decimal128_limits::exponent_bias);
+
+       /* Encode combination, exponent, and significand. */
+       if ((significand.high >> 49) & 1) {
+          /* Encode '11' into bits 1 to 3 */
+          dec.high |= (0x3ull << 61);
+          dec.high |= (biased_exponent & 0x3fffull) << 47;
+          dec.high |= significand.high & 0x7fffffffffffull;
+       } else {
+          dec.high |= (biased_exponent & 0x3fffull) << 49;
+          dec.high |= significand.high & 0x1ffffffffffffull;
+       }
+
+       dec.low = significand.low;
+
+       /* Encode sign */
+       if (is_negative) {
+          dec.high |= 0x8000000000000000ull;
+       }
+
+       return true;
+    }
+
+} // namespace bson
+} // namespace jsoncons
+
+#endif
diff --git a/include/jsoncons_ext/bson/bson_encoder.hpp b/include/jsoncons_ext/bson/bson_encoder.hpp
new file mode 100644
index 0000000..4569f06
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_encoder.hpp
@@ -0,0 +1,585 @@
+// Copyright 2018 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_BSON_ENCODER_HPP
+#define JSONCONS_BSON_BSON_ENCODER_HPP
+
+#include <string>
+#include <vector>
+#include <limits> // std::numeric_limits
+#include <memory>
+#include <utility> // std::move
+#include <jsoncons/json_exception.hpp>
+#include <jsoncons/json_visitor.hpp>
+#include <jsoncons/config/jsoncons_config.hpp>
+#include <jsoncons/sink.hpp>
+#include <jsoncons/detail/parse_number.hpp>
+#include <jsoncons_ext/bson/bson_type.hpp>
+#include <jsoncons_ext/bson/bson_error.hpp>
+#include <jsoncons_ext/bson/bson_options.hpp>
+#include <jsoncons_ext/bson/bson_decimal128.hpp>
+#include <jsoncons_ext/bson/bson_oid.hpp>
+
+namespace jsoncons { namespace bson {
+
+template<class Sink=jsoncons::binary_stream_sink,class Allocator=std::allocator<char>>
+class basic_bson_encoder final : public basic_json_visitor<char>
+{
+    enum class decimal_parse_state { start, integer, exp1, exp2, fraction1 };
+    static constexpr int64_t nanos_in_milli = 1000000;
+    static constexpr int64_t nanos_in_second = 1000000000;
+    static constexpr int64_t millis_in_second = 1000;
+public:
+    using allocator_type = Allocator;
+    using char_type = char;
+    using typename basic_json_visitor<char>::string_view_type;
+    using sink_type = Sink;
+
+private:
+    struct stack_item
+    {
+        jsoncons::bson::bson_container_type type_;
+        std::size_t offset_;
+        std::size_t name_offset_;
+        std::size_t index_;
+
+        stack_item(jsoncons::bson::bson_container_type type, std::size_t offset) noexcept
+           : type_(type), offset_(offset), name_offset_(0), index_(0)
+        {
+        }
+
+        std::size_t offset() const
+        {
+            return offset_;
+        }
+
+        std::size_t member_offset() const
+        {
+            return name_offset_;
+        }
+
+        void member_offset(std::size_t offset) 
+        {
+            name_offset_ = offset;
+        }
+
+        std::size_t next_index()
+        {
+            return index_++;
+        }
+
+        bool is_object() const
+        {
+            return type_ == jsoncons::bson::bson_container_type::document;
+        }
+
+
+    };
+
+    sink_type sink_;
+    const bson_encode_options options_;
+    allocator_type alloc_;
+
+    std::vector<stack_item> stack_;
+    std::vector<uint8_t> buffer_;
+    int nesting_depth_;
+
+    // Noncopyable and nonmoveable
+    basic_bson_encoder(const basic_bson_encoder&) = delete;
+    basic_bson_encoder& operator=(const basic_bson_encoder&) = delete;
+public:
+    explicit basic_bson_encoder(Sink&& sink, 
+                                const Allocator& alloc = Allocator())
+       : basic_bson_encoder(std::forward<Sink>(sink),
+                            bson_encode_options(),
+                            alloc)
+    {
+    }
+
+    explicit basic_bson_encoder(Sink&& sink, 
+                                const bson_encode_options& options, 
+                                const Allocator& alloc = Allocator())
+       : sink_(std::forward<Sink>(sink)),
+         options_(options),
+         alloc_(alloc), 
+         nesting_depth_(0)
+    {
+    }
+
+    ~basic_bson_encoder() noexcept
+    {
+        sink_.flush();
+    }
+
+    void reset()
+    {
+        stack_.clear();
+        buffer_.clear();
+        nesting_depth_ = 0;
+    }
+
+    void reset(Sink&& sink)
+    {
+        sink_ = std::move(sink);
+        reset();
+    }
+
+private:
+    // Implementing methods
+
+    void visit_flush() override
+    {
+        sink_.flush();
+    }
+
+    bool visit_begin_object(semantic_tag, const ser_context&, std::error_code& ec) override
+    {
+        if (JSONCONS_UNLIKELY(++nesting_depth_ > options_.max_nesting_depth()))
+        {
+            ec = bson_errc::max_nesting_depth_exceeded;
+            return false;
+        } 
+        if (buffer_.size() > 0)
+        {
+            if (stack_.empty())
+            {
+                ec = bson_errc::expected_bson_document;
+                return false;
+            }
+            before_value(jsoncons::bson::bson_type::document_type);
+        }
+
+        stack_.emplace_back(jsoncons::bson::bson_container_type::document, buffer_.size());
+        buffer_.insert(buffer_.end(), sizeof(int32_t), 0);
+
+        return true;
+    }
+
+    bool visit_end_object(const ser_context&, std::error_code&) override
+    {
+        JSONCONS_ASSERT(!stack_.empty());
+        --nesting_depth_;
+
+        buffer_.push_back(0x00);
+
+        std::size_t length = buffer_.size() - stack_.back().offset();
+        binary::native_to_little(static_cast<uint32_t>(length), buffer_.begin()+stack_.back().offset());
+
+        stack_.pop_back();
+        if (stack_.empty())
+        {
+            for (auto c : buffer_)
+            {
+                sink_.push_back(c);
+            }
+        }
+        return true;
+    }
+
+    bool visit_begin_array(semantic_tag, const ser_context&, std::error_code& ec) override
+    {
+        if (JSONCONS_UNLIKELY(++nesting_depth_ > options_.max_nesting_depth()))
+        {
+            ec = bson_errc::max_nesting_depth_exceeded;
+            return false;
+        } 
+        if (buffer_.size() > 0)
+        {
+            if (stack_.empty())
+            {
+                ec = bson_errc::expected_bson_document;
+                return false;
+            }
+            before_value(jsoncons::bson::bson_type::array_type);
+        }
+        stack_.emplace_back(jsoncons::bson::bson_container_type::array, buffer_.size());
+        buffer_.insert(buffer_.end(), sizeof(int32_t), 0);
+        return true;
+    }
+
+    bool visit_end_array(const ser_context&, std::error_code&) override
+    {
+        JSONCONS_ASSERT(!stack_.empty());
+        --nesting_depth_;
+
+        buffer_.push_back(0x00);
+
+        std::size_t length = buffer_.size() - stack_.back().offset();
+        binary::native_to_little(static_cast<uint32_t>(length), buffer_.begin()+stack_.back().offset());
+
+        stack_.pop_back();
+        if (stack_.empty())
+        {
+            for (auto c : buffer_)
+            {
+                sink_.push_back(c);
+            }
+        }
+        return true;
+    }
+
+    bool visit_key(const string_view_type& name, const ser_context&, std::error_code&) override
+    {
+        stack_.back().member_offset(buffer_.size());
+        buffer_.push_back(0x00); // reserve space for code
+        for (auto c : name)
+        {
+            buffer_.push_back(c);
+        }
+        buffer_.push_back(0x00);
+        return true;
+    }
+
+    bool visit_null(semantic_tag tag, const ser_context&, std::error_code& ec) override
+    {
+        if (stack_.empty())
+        {
+            ec = bson_errc::expected_bson_document;
+            return false;
+        }
+        switch (tag)
+        {
+            case semantic_tag::undefined:
+                before_value(jsoncons::bson::bson_type::undefined_type);
+                break;
+            default:
+                before_value(jsoncons::bson::bson_type::null_type);
+                break;
+        }
+        return true;
+    }
+
+    bool visit_bool(bool val, semantic_tag, const ser_context&, std::error_code& ec) override
+    {
+        if (stack_.empty())
+        {
+            ec = bson_errc::expected_bson_document;
+            return false;
+        }
+        before_value(jsoncons::bson::bson_type::bool_type);
+        if (val)
+        {
+            buffer_.push_back(0x01);
+        }
+        else
+        {
+            buffer_.push_back(0x00);
+        }
+
+        return true;
+    }
+
+    bool visit_string(const string_view_type& sv, semantic_tag tag, const ser_context&, std::error_code& ec) override
+    {
+        if (stack_.empty())
+        {
+            ec = bson_errc::expected_bson_document;
+            return false;
+        }
+
+        switch (tag)
+        {
+            case semantic_tag::float128:
+            {
+                before_value(jsoncons::bson::bson_type::decimal128_type);
+                decimal128_t dec;
+                auto rc = decimal128_from_chars(sv.data(), sv.data()+sv.size(), dec);
+                if (rc.ec != std::errc())
+                {
+                    ec = bson_errc::invalid_decimal128_string;
+                    return false;
+                }
+                binary::native_to_little(dec.low,std::back_inserter(buffer_));
+                binary::native_to_little(dec.high,std::back_inserter(buffer_));
+                break;
+            }
+            case semantic_tag::id:
+            {
+                before_value(jsoncons::bson::bson_type::object_id_type);
+                oid_t oid(sv);
+                for (auto b : oid)
+                {
+                    buffer_.push_back(b);
+                }
+                break;
+            }
+            case semantic_tag::regex:
+            {
+                before_value(jsoncons::bson::bson_type::regex_type);
+                std::size_t first = sv.find_first_of('/');
+                std::size_t last = sv.find_last_of('/');
+                if (first == string_view::npos || last == string_view::npos || first == last)
+                {
+                    ec = bson_errc::invalid_regex_string;
+                    return false;
+                }
+                string_view regex = sv.substr(first+1,last-1);
+                for (auto c : regex)
+                {
+                    buffer_.push_back(c);
+                }
+                buffer_.push_back(0x00);
+                string_view options = sv.substr(last+1);
+                for (auto c : options)
+                {
+                    buffer_.push_back(c);
+                }
+                buffer_.push_back(0x00);
+                break;
+            }
+            default:
+                switch (tag)
+                {
+                    case semantic_tag::code:
+                        before_value(jsoncons::bson::bson_type::javascript_type);
+                        break;
+                    default:
+                        before_value(jsoncons::bson::bson_type::string_type);
+                        break;
+                }
+                std::size_t offset = buffer_.size();
+                buffer_.insert(buffer_.end(), sizeof(int32_t), 0);
+                std::size_t string_offset = buffer_.size();
+                auto sink = unicode_traits::validate(sv.data(), sv.size());
+                if (sink.ec != unicode_traits::conv_errc())
+                {
+                    ec = bson_errc::invalid_utf8_text_string;
+                    return false;
+                }
+                for (auto c : sv)
+                {
+                    buffer_.push_back(c);
+                }
+                buffer_.push_back(0x00);
+                std::size_t length = buffer_.size() - string_offset;
+                binary::native_to_little(static_cast<uint32_t>(length), buffer_.begin()+offset);
+                break;
+        }
+
+        return true;
+    }
+
+    bool visit_byte_string(const byte_string_view& b, 
+                           semantic_tag, 
+                           const ser_context&,
+                           std::error_code& ec) override
+    {
+        if (stack_.empty())
+        {
+            ec = bson_errc::expected_bson_document;
+            return false;
+        }
+        before_value(jsoncons::bson::bson_type::binary_type);
+
+        std::size_t offset = buffer_.size();
+        buffer_.insert(buffer_.end(), sizeof(int32_t), 0);
+        std::size_t string_offset = buffer_.size();
+
+        buffer_.push_back(0x80); // default subtype
+
+        for (auto c : b)
+        {
+            buffer_.push_back(c);
+        }
+        std::size_t length = buffer_.size() - string_offset - 1;
+        binary::native_to_little(static_cast<uint32_t>(length), buffer_.begin()+offset);
+
+        return true;
+    }
+
+    bool visit_byte_string(const byte_string_view& b, 
+                           uint64_t ext_tag, 
+                           const ser_context&,
+                           std::error_code& ec) override
+    {
+        if (stack_.empty())
+        {
+            ec = bson_errc::expected_bson_document;
+            return false;
+        }
+        before_value(jsoncons::bson::bson_type::binary_type);
+
+        std::size_t offset = buffer_.size();
+        buffer_.insert(buffer_.end(), sizeof(int32_t), 0);
+        std::size_t string_offset = buffer_.size();
+
+        buffer_.push_back(static_cast<uint8_t>(ext_tag)); // default subtype
+
+        for (auto c : b)
+        {
+            buffer_.push_back(c);
+        }
+        std::size_t length = buffer_.size() - string_offset - 1;
+        binary::native_to_little(static_cast<uint32_t>(length), buffer_.begin()+offset);
+
+        return true;
+    }
+
+    bool visit_int64(int64_t val, 
+                     semantic_tag tag, 
+                     const ser_context&,
+                     std::error_code& ec) override
+    {
+        static constexpr int64_t min_value_div_1000 = (std::numeric_limits<int64_t>::min)() / 1000;
+        static constexpr int64_t max_value_div_1000 = (std::numeric_limits<int64_t>::max)() / 1000;
+        if (stack_.empty())
+        {
+            ec = bson_errc::expected_bson_document;
+            return false;
+        }
+
+        switch (tag)
+        {
+            case semantic_tag::epoch_second:
+                if (val < min_value_div_1000)
+                {
+                    ec = bson_errc::datetime_too_small;
+                    return false;
+                }
+                if (val > max_value_div_1000)
+                {
+                    ec = bson_errc::datetime_too_large;
+                    return false;
+                }
+                before_value(jsoncons::bson::bson_type::datetime_type);
+                binary::native_to_little(val*millis_in_second,std::back_inserter(buffer_));
+                return true;
+            case semantic_tag::epoch_milli:
+                before_value(jsoncons::bson::bson_type::datetime_type);
+                binary::native_to_little(val,std::back_inserter(buffer_));
+                return true;
+            case semantic_tag::epoch_nano:
+                before_value(jsoncons::bson::bson_type::datetime_type);
+                if (val != 0)
+                {
+                    val /= nanos_in_milli;
+                }
+                binary::native_to_little(static_cast<int64_t>(val),std::back_inserter(buffer_));
+                return true;
+            default:
+            {
+                if (val >= (std::numeric_limits<int32_t>::lowest)() && val <= (std::numeric_limits<int32_t>::max)())
+                {
+                    before_value(jsoncons::bson::bson_type::int32_type);
+                    binary::native_to_little(static_cast<uint32_t>(val),std::back_inserter(buffer_));
+                }
+                else 
+                {
+                    before_value(jsoncons::bson::bson_type::int64_type);
+                    binary::native_to_little(static_cast<int64_t>(val),std::back_inserter(buffer_));
+                }
+                return true;
+            }
+        }
+    }
+
+    bool visit_uint64(uint64_t val, 
+                      semantic_tag tag, 
+                      const ser_context&,
+                      std::error_code& ec) override
+    {
+        static constexpr uint64_t max_value_div_1000 = (std::numeric_limits<uint64_t>::max)() / 1000;
+        if (stack_.empty())
+        {
+            ec = bson_errc::expected_bson_document;
+            return false;
+        }
+
+        switch (tag)
+        {
+            case semantic_tag::epoch_second:
+                if (val > max_value_div_1000)
+                {
+                    ec = bson_errc::datetime_too_large;
+                    return false;
+                }
+                before_value(jsoncons::bson::bson_type::datetime_type);
+                binary::native_to_little(static_cast<int64_t>(val*millis_in_second),std::back_inserter(buffer_));
+                return true;
+            case semantic_tag::epoch_milli:
+                before_value(jsoncons::bson::bson_type::datetime_type);
+                binary::native_to_little(static_cast<int64_t>(val),std::back_inserter(buffer_));
+                return true;
+            case semantic_tag::epoch_nano:
+                before_value(jsoncons::bson::bson_type::datetime_type);
+                if (val != 0)
+                {
+                    val /= nanos_in_second;
+                }
+                binary::native_to_little(static_cast<int64_t>(val),std::back_inserter(buffer_));
+                return true;
+            default:
+            {
+                bool more;
+                if (val <= static_cast<uint64_t>((std::numeric_limits<int32_t>::max)()))
+                {
+                    before_value(jsoncons::bson::bson_type::int32_type);
+                    binary::native_to_little(static_cast<uint32_t>(val),std::back_inserter(buffer_));
+                    more = true;
+                }
+                else if (val <= static_cast<uint64_t>((std::numeric_limits<int64_t>::max)()))
+                {
+                    before_value(jsoncons::bson::bson_type::int64_type);
+                    binary::native_to_little(static_cast<uint64_t>(val),std::back_inserter(buffer_));
+                    more = true;
+                }
+                else
+                {
+                    ec = bson_errc::number_too_large;
+                    more = false;
+                }
+                return more;
+            }
+        }
+    }
+
+    bool visit_double(double val, 
+                      semantic_tag,
+                      const ser_context&,
+                      std::error_code& ec) override
+    {
+        if (stack_.empty())
+        {
+            ec = bson_errc::expected_bson_document;
+            return false;
+        }
+        before_value(jsoncons::bson::bson_type::double_type);
+        binary::native_to_little(val,std::back_inserter(buffer_));
+        return true;
+    }
+
+    void before_value(uint8_t code) 
+    {
+        JSONCONS_ASSERT(!stack_.empty());
+        if (stack_.back().is_object())
+        {
+            buffer_[stack_.back().member_offset()] = code;
+        }
+        else
+        {
+            buffer_.push_back(code);
+            std::string name = std::to_string(stack_.back().next_index());
+            buffer_.insert(buffer_.end(), name.begin(), name.end());
+            buffer_.push_back(0x00);
+        }
+    }
+};
+
+using bson_stream_encoder = basic_bson_encoder<jsoncons::binary_stream_sink>;
+using bson_bytes_encoder = basic_bson_encoder<jsoncons::bytes_sink<std::vector<uint8_t>>>;
+
+#if !defined(JSONCONS_NO_DEPRECATED)
+template<class Sink=jsoncons::binary_stream_sink>
+using basic_bson_serializer = basic_bson_encoder<Sink>; 
+
+JSONCONS_DEPRECATED_MSG("Instead, use bson_stream_encoder") typedef bson_stream_encoder bson_encoder;
+JSONCONS_DEPRECATED_MSG("Instead, use bson_stream_encoder") typedef bson_stream_encoder bson_serializer;
+JSONCONS_DEPRECATED_MSG("Instead, use bson_bytes_encoder")  typedef bson_bytes_encoder bson_buffer_serializer;
+
+#endif
+
+}}
+#endif
diff --git a/include/jsoncons_ext/bson/bson_error.hpp b/include/jsoncons_ext/bson/bson_error.hpp
new file mode 100644
index 0000000..85cf24d
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_error.hpp
@@ -0,0 +1,103 @@
+/// Copyright 2018 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_BSON_ERROR_HPP
+#define JSONCONS_BSON_BSON_ERROR_HPP
+
+#include <system_error>
+#include <jsoncons/config/jsoncons_config.hpp>
+
+namespace jsoncons { namespace bson {
+
+enum class bson_errc
+{
+    success = 0,
+    unexpected_eof = 1,
+    source_error,
+    invalid_utf8_text_string,
+    max_nesting_depth_exceeded,
+    string_length_is_non_positive,
+    length_is_negative,
+    number_too_large,
+    invalid_decimal128_string,
+    datetime_too_small,
+    datetime_too_large,
+    expected_bson_document,
+    invalid_regex_string,
+    size_mismatch,
+    unknown_type
+};
+
+class bson_error_category_impl
+   : public std::error_category
+{
+public:
+    const char* name() const noexcept override
+    {
+        return "jsoncons/bson";
+    }
+    std::string message(int ev) const override
+    {
+        switch (static_cast<bson_errc>(ev))
+        {
+            case bson_errc::unexpected_eof:
+                return "Unexpected end of file";
+            case bson_errc::source_error:
+                return "Source error";
+            case bson_errc::invalid_utf8_text_string:
+                return "Illegal UTF-8 encoding in text string";
+            case bson_errc::max_nesting_depth_exceeded:
+                return "Data item nesting exceeds limit in options";
+            case bson_errc::string_length_is_non_positive:
+                return "Request for the length of a string returned a non-positive result";
+            case bson_errc::length_is_negative:
+                return "Request for the length of a binary returned a negative result";
+            case bson_errc::unknown_type:
+                return "An unknown type was found in the stream";
+            case bson_errc::number_too_large:
+                return "Number too large";
+            case bson_errc::invalid_decimal128_string:
+                return "Invalid decimal128 string";
+            case bson_errc::datetime_too_large:
+                return "datetime too large";
+            case bson_errc::datetime_too_small:
+                return "datetime too small";
+            case bson_errc::expected_bson_document:
+                return "Expected BSON document";
+            case bson_errc::invalid_regex_string:
+                return "Invalid regex string";
+            case bson_errc::size_mismatch:
+                return "Document or array size doesn't match bytes read";
+            default:
+                return "Unknown BSON parser error";
+        }
+    }
+};
+
+inline
+const std::error_category& bson_error_category()
+{
+  static bson_error_category_impl instance;
+  return instance;
+}
+
+inline 
+std::error_code make_error_code(bson_errc result)
+{
+    return std::error_code(static_cast<int>(result),bson_error_category());
+}
+
+
+}}
+
+namespace std {
+    template<>
+    struct is_error_code_enum<jsoncons::bson::bson_errc> : public true_type
+    {
+    };
+}
+
+#endif
diff --git a/include/jsoncons_ext/bson/bson_oid.hpp b/include/jsoncons_ext/bson/bson_oid.hpp
new file mode 100644
index 0000000..065d8da
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_oid.hpp
@@ -0,0 +1,245 @@
+#ifndef JSONCONS_BSON_BSON_OID_HPP
+#define JSONCONS_BSON_BSON_OID_HPP
+
+/*
+ *  Implements class oid_t and non member function bson_oid_to_string
+ *  
+ *  Based on the libjson functions bson_oid_to_string 
+ *  and bson_oid_init_from_string_unsafe , available at
+ *  https://github.com/mongodb/mongo-c-driver/blob/master/src/libbson/src/bson/bson-oid.h
+ *  and https://github.com/mongodb/mongo-c-driver/blob/master/src/libbson/src/bson/bson-oid.c
+ *  
+*/
+
+/*
+ * Copyright 2015 MongoDB, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cstdlib>
+#include <cstring>
+#include <ctype.h>
+#include <system_error>
+#include <algorithm>
+#include <string>
+#include <type_traits>
+#include <array>
+#include <jsoncons/config/jsoncons_config.hpp>
+
+namespace jsoncons { namespace bson {
+
+    class oid_t
+    {
+        std::array<uint8_t,12> bytes_;
+    public:
+        using iterator = std::array<uint8_t,12>::iterator;
+        using const_iterator = std::array<uint8_t,12>::const_iterator;
+
+        oid_t(const std::array<uint8_t,12>& bytes)
+            : bytes_(bytes)
+        {
+        }
+        oid_t(uint8_t data[12])
+        {
+            std::memcpy(bytes_.data(),data,12);
+        }
+
+        oid_t(const string_view& str)
+        {
+            for (std::size_t i = 0; i < bytes_.size(); i++) 
+            {
+               bytes_[i] = ((parse_hex_char (str[2 * i]) << 4) |
+                           (parse_hex_char (str[2 * i + 1])));
+            }
+        }
+
+        const uint8_t* data() const
+        {
+            return bytes_.data();
+        }
+
+        std::size_t size() const
+        {
+            return bytes_.size();
+        }
+
+        iterator begin()
+        {
+            return bytes_.begin();
+        }
+
+        iterator end()
+        {
+            return bytes_.end();
+        }
+
+        const_iterator begin() const
+        {
+            return bytes_.begin();
+        }
+
+        const_iterator end() const
+        {
+            return bytes_.end();
+        }
+
+    private:
+
+        static uint8_t parse_hex_char (char hex)
+        {
+           switch (hex) {
+           case '0':
+              return 0;
+           case '1':
+              return 1;
+           case '2':
+              return 2;
+           case '3':
+              return 3;
+           case '4':
+              return 4;
+           case '5':
+              return 5;
+           case '6':
+              return 6;
+           case '7':
+              return 7;
+           case '8':
+              return 8;
+           case '9':
+              return 9;
+           case 'a':
+           case 'A':
+              return 0xa;
+           case 'b':
+           case 'B':
+              return 0xb;
+           case 'c':
+           case 'C':
+              return 0xc;
+           case 'd':
+           case 'D':
+              return 0xd;
+           case 'e':
+           case 'E':
+              return 0xe;
+           case 'f':
+           case 'F':
+              return 0xf;
+           default:
+              return 0;
+           }
+        }
+    };
+
+    namespace detail {
+
+        inline
+        const uint16_t* get_hex_char_pairs(std::true_type) // big endian
+        {
+            static const uint16_t hex_char_pairs[] = {
+               12336, 12337, 12338, 12339, 12340, 12341, 12342, 12343, 12344, 12345, 12385,
+               12386, 12387, 12388, 12389, 12390, 12592, 12593, 12594, 12595, 12596, 12597,
+               12598, 12599, 12600, 12601, 12641, 12642, 12643, 12644, 12645, 12646, 12848,
+               12849, 12850, 12851, 12852, 12853, 12854, 12855, 12856, 12857, 12897, 12898,
+               12899, 12900, 12901, 12902, 13104, 13105, 13106, 13107, 13108, 13109, 13110,
+               13111, 13112, 13113, 13153, 13154, 13155, 13156, 13157, 13158, 13360, 13361,
+               13362, 13363, 13364, 13365, 13366, 13367, 13368, 13369, 13409, 13410, 13411,
+               13412, 13413, 13414, 13616, 13617, 13618, 13619, 13620, 13621, 13622, 13623,
+               13624, 13625, 13665, 13666, 13667, 13668, 13669, 13670, 13872, 13873, 13874,
+               13875, 13876, 13877, 13878, 13879, 13880, 13881, 13921, 13922, 13923, 13924,
+               13925, 13926, 14128, 14129, 14130, 14131, 14132, 14133, 14134, 14135, 14136,
+               14137, 14177, 14178, 14179, 14180, 14181, 14182, 14384, 14385, 14386, 14387,
+               14388, 14389, 14390, 14391, 14392, 14393, 14433, 14434, 14435, 14436, 14437,
+               14438, 14640, 14641, 14642, 14643, 14644, 14645, 14646, 14647, 14648, 14649,
+               14689, 14690, 14691, 14692, 14693, 14694, 24880, 24881, 24882, 24883, 24884,
+               24885, 24886, 24887, 24888, 24889, 24929, 24930, 24931, 24932, 24933, 24934,
+               25136, 25137, 25138, 25139, 25140, 25141, 25142, 25143, 25144, 25145, 25185,
+               25186, 25187, 25188, 25189, 25190, 25392, 25393, 25394, 25395, 25396, 25397,
+               25398, 25399, 25400, 25401, 25441, 25442, 25443, 25444, 25445, 25446, 25648,
+               25649, 25650, 25651, 25652, 25653, 25654, 25655, 25656, 25657, 25697, 25698,
+               25699, 25700, 25701, 25702, 25904, 25905, 25906, 25907, 25908, 25909, 25910,
+               25911, 25912, 25913, 25953, 25954, 25955, 25956, 25957, 25958, 26160, 26161,
+               26162, 26163, 26164, 26165, 26166, 26167, 26168, 26169, 26209, 26210, 26211,
+               26212, 26213, 26214};
+
+            return hex_char_pairs;
+        }
+
+        inline
+        const uint16_t* get_hex_char_pairs(std::false_type) // little endian
+        {
+            static const uint16_t hex_char_pairs[] = {
+                12336, 12592, 12848, 13104, 13360, 13616, 13872, 14128, 14384, 14640, 24880,
+                25136, 25392, 25648, 25904, 26160, 12337, 12593, 12849, 13105, 13361, 13617,
+                13873, 14129, 14385, 14641, 24881, 25137, 25393, 25649, 25905, 26161, 12338,
+                12594, 12850, 13106, 13362, 13618, 13874, 14130, 14386, 14642, 24882, 25138,
+                25394, 25650, 25906, 26162, 12339, 12595, 12851, 13107, 13363, 13619, 13875,
+                14131, 14387, 14643, 24883, 25139, 25395, 25651, 25907, 26163, 12340, 12596,
+                12852, 13108, 13364, 13620, 13876, 14132, 14388, 14644, 24884, 25140, 25396,
+                25652, 25908, 26164, 12341, 12597, 12853, 13109, 13365, 13621, 13877, 14133,
+                14389, 14645, 24885, 25141, 25397, 25653, 25909, 26165, 12342, 12598, 12854,
+                13110, 13366, 13622, 13878, 14134, 14390, 14646, 24886, 25142, 25398, 25654,
+                25910, 26166, 12343, 12599, 12855, 13111, 13367, 13623, 13879, 14135, 14391,
+                14647, 24887, 25143, 25399, 25655, 25911, 26167, 12344, 12600, 12856, 13112,
+                13368, 13624, 13880, 14136, 14392, 14648, 24888, 25144, 25400, 25656, 25912,
+                26168, 12345, 12601, 12857, 13113, 13369, 13625, 13881, 14137, 14393, 14649,
+                24889, 25145, 25401, 25657, 25913, 26169, 12385, 12641, 12897, 13153, 13409,
+                13665, 13921, 14177, 14433, 14689, 24929, 25185, 25441, 25697, 25953, 26209,
+                12386, 12642, 12898, 13154, 13410, 13666, 13922, 14178, 14434, 14690, 24930,
+                25186, 25442, 25698, 25954, 26210, 12387, 12643, 12899, 13155, 13411, 13667,
+                13923, 14179, 14435, 14691, 24931, 25187, 25443, 25699, 25955, 26211, 12388,
+                12644, 12900, 13156, 13412, 13668, 13924, 14180, 14436, 14692, 24932, 25188,
+                25444, 25700, 25956, 26212, 12389, 12645, 12901, 13157, 13413, 13669, 13925,
+                14181, 14437, 14693, 24933, 25189, 25445, 25701, 25957, 26213, 12390, 12646,
+                12902, 13158, 13414, 13670, 13926, 14182, 14438, 14694, 24934, 25190, 25446,
+                25702, 25958, 26214};
+
+            return hex_char_pairs;
+        }
+
+        inline
+        void init_hex_char_pairs(const oid_t& oid, uint16_t* data)
+        {
+            const uint8_t* bytes = oid.data();
+            const uint16_t* gHexCharPairs = get_hex_char_pairs(std::integral_constant<bool, jsoncons::endian::native == jsoncons::endian::big>());
+
+            data[0] = gHexCharPairs[bytes[0]];
+            data[1] = gHexCharPairs[bytes[1]];
+            data[2] = gHexCharPairs[bytes[2]];
+            data[3] = gHexCharPairs[bytes[3]];
+            data[4] = gHexCharPairs[bytes[4]];
+            data[5] = gHexCharPairs[bytes[5]];
+            data[6] = gHexCharPairs[bytes[6]];
+            data[7] = gHexCharPairs[bytes[7]];
+            data[8] = gHexCharPairs[bytes[8]];
+            data[9] = gHexCharPairs[bytes[9]];
+            data[10] = gHexCharPairs[bytes[10]];
+            data[11] = gHexCharPairs[bytes[11]];
+        }
+
+    } // namsepace detail
+
+    template <typename StringT>
+    inline 
+    void to_string(const oid_t& oid, StringT& s)
+    {
+        s.resize(24);
+        detail::init_hex_char_pairs(oid, reinterpret_cast<uint16_t*>(&s[0]));
+    }
+
+} // namespace bson
+} // namespace jsoncons
+
+#endif
diff --git a/include/jsoncons_ext/bson/bson_options.hpp b/include/jsoncons_ext/bson/bson_options.hpp
new file mode 100644
index 0000000..0e4620e
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_options.hpp
@@ -0,0 +1,75 @@
+// Copyright 2019 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_BSON_OPTIONS_HPP
+#define JSONCONS_BSON_BSON_OPTIONS_HPP
+
+#include <string>
+#include <limits> // std::numeric_limits
+#include <cwchar>
+#include <jsoncons/json_exception.hpp>
+#include <jsoncons_ext/bson/bson_type.hpp>
+
+namespace jsoncons { namespace bson {
+
+class bson_options;
+
+class bson_options_common
+{
+    friend class bson_options;
+
+    int max_nesting_depth_;
+protected:
+    virtual ~bson_options_common() = default;
+
+    bson_options_common()
+        : max_nesting_depth_(1024)
+    {
+    }
+
+    bson_options_common(const bson_options_common&) = default;
+    bson_options_common& operator=(const bson_options_common&) = default;
+    bson_options_common(bson_options_common&&) = default;
+    bson_options_common& operator=(bson_options_common&&) = default;
+public:
+    int max_nesting_depth() const 
+    {
+        return max_nesting_depth_;
+    }
+};
+
+class bson_decode_options : public virtual bson_options_common
+{
+    friend class bson_options;
+public:
+    bson_decode_options()
+    {
+    }
+};
+
+class bson_encode_options : public virtual bson_options_common
+{
+    friend class bson_options;
+public:
+    bson_encode_options()
+    {
+    }
+};
+
+class bson_options final : public bson_decode_options, public bson_encode_options
+{
+public:
+    using bson_options_common::max_nesting_depth;
+
+    bson_options& max_nesting_depth(int value)
+    {
+        this->max_nesting_depth_ = value;
+        return *this;
+    }
+};
+
+}}
+#endif
diff --git a/include/jsoncons_ext/bson/bson_parser.hpp b/include/jsoncons_ext/bson/bson_parser.hpp
new file mode 100644
index 0000000..2dc6e75
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_parser.hpp
@@ -0,0 +1,645 @@
+// Copyright 2017 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_BSON_PARSER_HPP
+#define JSONCONS_BSON_BSON_PARSER_HPP
+
+#include <string>
+#include <vector>
+#include <memory>
+#include <utility> // std::move
+#include <jsoncons/json.hpp>
+#include <jsoncons/source.hpp>
+#include <jsoncons/json_visitor.hpp>
+#include <jsoncons/config/jsoncons_config.hpp>
+#include <jsoncons_ext/bson/bson_type.hpp>
+#include <jsoncons_ext/bson/bson_decimal128.hpp>
+#include <jsoncons_ext/bson/bson_error.hpp>
+#include <jsoncons_ext/bson/bson_options.hpp>
+#include <jsoncons_ext/bson/bson_oid.hpp>
+
+namespace jsoncons { namespace bson {
+
+enum class parse_mode {root,accept,document,array,value};
+
+struct parse_state 
+{
+    parse_mode mode; 
+    std::size_t length;
+    std::size_t pos;
+    uint8_t type;
+    std::size_t index;
+
+    parse_state(parse_mode mode_, std::size_t length_, std::size_t pos_, uint8_t type_ = 0) noexcept
+        : mode(mode_), length(length_), pos(pos_), type(type_), index(0)
+    {
+    }
+
+    parse_state(const parse_state&) = default;
+    parse_state(parse_state&&) = default;
+    parse_state& operator=(const parse_state&) = default;
+    parse_state& operator=(parse_state&&) = default;
+};
+
+template <class Source,class Allocator=std::allocator<char>>
+class basic_bson_parser : public ser_context
+{
+    using char_type = char;
+    using char_traits_type = std::char_traits<char>;
+    using temp_allocator_type = Allocator;
+    using char_allocator_type = typename std::allocator_traits<temp_allocator_type>:: template rebind_alloc<char_type>;                  
+    using byte_allocator_type = typename std::allocator_traits<temp_allocator_type>:: template rebind_alloc<uint8_t>;                  
+    using parse_state_allocator_type = typename std::allocator_traits<temp_allocator_type>:: template rebind_alloc<parse_state>;                         
+
+    Source source_;
+    bson_decode_options options_;
+    bool more_;
+    bool done_;
+    std::vector<uint8_t,byte_allocator_type> bytes_buffer_;
+    std::basic_string<char,std::char_traits<char>,char_allocator_type> text_buffer_;
+    std::vector<parse_state,parse_state_allocator_type> state_stack_;
+public:
+    template <class Sourceable>
+    basic_bson_parser(Sourceable&& source,
+                      const bson_decode_options& options = bson_decode_options(),
+                      const Allocator alloc = Allocator())
+       : source_(std::forward<Sourceable>(source)), 
+         options_(options),
+         more_(true), 
+         done_(false),
+         text_buffer_(alloc),
+         state_stack_(alloc)
+    {
+        state_stack_.emplace_back(parse_mode::root,0,0);
+    }
+
+    void restart()
+    {
+        more_ = true;
+    }
+
+    void reset()
+    {
+        more_ = true;
+        done_ = false;
+        bytes_buffer_.clear();
+        text_buffer_.clear();
+        state_stack_.clear();
+        state_stack_.emplace_back(parse_mode::root,0,0);
+    }
+
+    template <class Sourceable>
+    void reset(Sourceable&& source)
+    {
+        source_ = std::forward<Sourceable>(source);
+        reset();
+    }
+
+    bool done() const
+    {
+        return done_;
+    }
+
+    bool stopped() const
+    {
+        return !more_;
+    }
+
+    std::size_t line() const override
+    {
+        return 0;
+    }
+
+    std::size_t column() const override
+    {
+        return source_.position();
+    }
+
+    void array_expected(json_visitor& visitor, std::error_code& ec)
+    {
+        if (state_stack_.size() == 2 && state_stack_.back().mode == parse_mode::document)
+        {
+            state_stack_.back().mode = parse_mode::array;
+            more_ = visitor.begin_array(semantic_tag::none, *this, ec);
+        }
+    }
+
+    void parse(json_visitor& visitor, std::error_code& ec)
+    {
+        if (JSONCONS_UNLIKELY(source_.is_error()))
+        {
+            ec = bson_errc::source_error;
+            more_ = false;
+            return;
+        }
+        
+        while (!done_ && more_)
+        {
+            switch (state_stack_.back().mode)
+            {
+                case parse_mode::root:
+                    state_stack_.back().mode = parse_mode::accept;
+                    begin_document(visitor, ec);
+                    break;
+                case parse_mode::document:
+                {
+                    uint8_t type;
+                    std::size_t n = source_.read(&type, 1);
+                    state_stack_.back().pos += n;
+                    if (JSONCONS_UNLIKELY(n != 1))
+                    {
+                        ec = bson_errc::unexpected_eof;
+                        more_ = false;
+                        return;
+                    }
+                    if (type != 0x00)
+                    {
+                        read_e_name(visitor,jsoncons::bson::bson_container_type::document,ec);
+                        state_stack_.back().mode = parse_mode::value;
+                        state_stack_.back().type = type;
+                    }
+                    else
+                    {
+                        end_document(visitor,ec);
+                    }
+                    break;
+                }
+                case parse_mode::array:
+                {
+                    uint8_t type;
+                    std::size_t n = source_.read(&type, 1);
+                    state_stack_.back().pos += n;
+                    if (JSONCONS_UNLIKELY(n != 1))
+                    {
+                        ec = bson_errc::unexpected_eof;
+                        more_ = false;
+                        return;
+                    }
+                    if (type != 0x00)
+                    {
+                        read_e_name(visitor,jsoncons::bson::bson_container_type::array,ec);
+                        read_value(visitor, type, ec);
+                    }
+                    else
+                    {
+                        end_array(visitor,ec);
+                    }
+                    break;
+                }
+                case parse_mode::value:
+                    state_stack_.back().mode = parse_mode::document;
+                    read_value(visitor,state_stack_.back().type,ec);
+                    break;
+                case parse_mode::accept:
+                {
+                    JSONCONS_ASSERT(state_stack_.size() == 1);
+                    state_stack_.clear();
+                    more_ = false;
+                    done_ = true;
+                    visitor.flush();
+                    break;
+                }
+            }
+        }
+    }
+
+private:
+
+    void begin_document(json_visitor& visitor, std::error_code& ec)
+    {
+        if (JSONCONS_UNLIKELY(static_cast<int>(state_stack_.size()) > options_.max_nesting_depth()))
+        {
+            ec = bson_errc::max_nesting_depth_exceeded;
+            more_ = false;
+            return;
+        } 
+
+        uint8_t buf[sizeof(int32_t)]; 
+        size_t n = source_.read(buf, sizeof(int32_t));
+        if (JSONCONS_UNLIKELY(n != sizeof(int32_t)))
+        {
+            ec = bson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+
+        auto length = binary::little_to_native<int32_t>(buf, sizeof(buf));
+
+        more_ = visitor.begin_object(semantic_tag::none, *this, ec);
+        state_stack_.emplace_back(parse_mode::document,length,n);
+    }
+
+    void end_document(json_visitor& visitor, std::error_code& ec)
+    {
+        JSONCONS_ASSERT(state_stack_.size() >= 2);
+
+        more_ = visitor.end_object(*this,ec);
+        if (JSONCONS_UNLIKELY(state_stack_.back().pos != state_stack_.back().length))
+        {
+            ec = bson_errc::size_mismatch;
+            more_ = false;
+            return;
+        }
+        std::size_t pos = state_stack_.back().pos;
+        state_stack_.pop_back();
+        state_stack_.back().pos += pos;
+    }
+
+    void begin_array(json_visitor& visitor, std::error_code& ec)
+    {
+        if (JSONCONS_UNLIKELY(static_cast<int>(state_stack_.size()) > options_.max_nesting_depth()))
+        {
+            ec = bson_errc::max_nesting_depth_exceeded;
+            more_ = false;
+            return;
+        } 
+        uint8_t buf[sizeof(int32_t)]; 
+        std::size_t n = source_.read(buf, sizeof(int32_t));
+        if (JSONCONS_UNLIKELY(n != sizeof(int32_t)))
+        {
+            ec = bson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+        auto length = binary::little_to_native<int32_t>(buf, sizeof(buf));
+
+        more_ = visitor.begin_array(semantic_tag::none, *this, ec);
+        if (ec)
+        {
+            return;
+        }
+        state_stack_.emplace_back(parse_mode::array, length, n);
+    }
+
+    void end_array(json_visitor& visitor, std::error_code& ec)
+    {
+        JSONCONS_ASSERT(state_stack_.size() >= 2);
+
+        more_ = visitor.end_array(*this, ec);
+        if (JSONCONS_UNLIKELY(state_stack_.back().pos != state_stack_.back().length))
+        {
+            ec = bson_errc::size_mismatch;
+            more_ = false;
+            return;
+        }
+        std::size_t pos = state_stack_.back().pos;
+        state_stack_.pop_back();
+        state_stack_.back().pos += pos;
+    }
+
+    void read_e_name(json_visitor& visitor, jsoncons::bson::bson_container_type type, std::error_code& ec)
+    {
+        text_buffer_.clear();
+        read_cstring(ec);
+        if (ec)
+        {
+            return;
+        }
+        if (type == jsoncons::bson::bson_container_type::document)
+        {
+            auto result = unicode_traits::validate(text_buffer_.data(),text_buffer_.size());
+            if (JSONCONS_UNLIKELY(result.ec != unicode_traits::conv_errc()))
+            {
+                ec = bson_errc::invalid_utf8_text_string;
+                more_ = false;
+                return;
+            }
+            more_ = visitor.key(jsoncons::basic_string_view<char>(text_buffer_.data(),text_buffer_.length()), *this, ec);
+        }
+    }
+
+    void read_value(json_visitor& visitor, uint8_t type, std::error_code& ec)
+    {
+        switch (type)
+        {
+            case jsoncons::bson::bson_type::double_type:
+            {
+                uint8_t buf[sizeof(double)]; 
+                std::size_t n = source_.read(buf, sizeof(double));
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != sizeof(double)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                double res = binary::little_to_native<double>(buf, sizeof(buf));
+                more_ = visitor.double_value(res, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::symbol_type:
+            case jsoncons::bson::bson_type::min_key_type:
+            case jsoncons::bson::bson_type::max_key_type:
+            case jsoncons::bson::bson_type::string_type:
+            {
+                text_buffer_.clear();
+                read_string(ec);
+                if (ec)
+                {
+                    return;
+                }
+                auto result = unicode_traits::validate(text_buffer_.data(), text_buffer_.size());
+                if (JSONCONS_UNLIKELY(result.ec != unicode_traits::conv_errc()))
+                {
+                    ec = bson_errc::invalid_utf8_text_string;
+                    more_ = false;
+                    return;
+                }
+                more_ = visitor.string_value(text_buffer_, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::javascript_type:
+            {
+                text_buffer_.clear();
+                read_string(ec);
+                if (ec)
+                {
+                    return;
+                }
+                auto result = unicode_traits::validate(text_buffer_.data(), text_buffer_.size());
+                if (JSONCONS_UNLIKELY(result.ec != unicode_traits::conv_errc()))
+                {
+                    ec = bson_errc::invalid_utf8_text_string;
+                    more_ = false;
+                    return;
+                }
+                more_ = visitor.string_value(text_buffer_, semantic_tag::code, *this, ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::regex_type:
+            {
+                text_buffer_.clear();
+                text_buffer_.push_back('/');
+                read_cstring(ec);
+                if (ec)
+                {
+                    return;
+                }
+                text_buffer_.push_back('/');
+                read_cstring(ec);
+                if (ec)
+                {
+                    return;
+                }
+                more_ = visitor.string_value(text_buffer_, semantic_tag::regex, *this, ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::document_type: 
+            {
+                begin_document(visitor,ec);
+                break;
+            }
+
+            case jsoncons::bson::bson_type::array_type: 
+            {
+                begin_array(visitor,ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::undefined_type: 
+                {
+                    more_ = visitor.null_value(semantic_tag::undefined, *this, ec);
+                    break;
+                }
+            case jsoncons::bson::bson_type::null_type: 
+            {
+                more_ = visitor.null_value(semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::bool_type:
+            {
+                uint8_t c;
+                std::size_t n = source_.read(&c, 1);
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != 1))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                more_ = visitor.bool_value(c != 0, semantic_tag::none, *this, ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::int32_type: 
+            {
+                uint8_t buf[sizeof(int32_t)]; 
+                std::size_t n = source_.read(buf, sizeof(int32_t));
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != sizeof(int32_t)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                auto val = binary::little_to_native<int32_t>(buf, sizeof(buf));
+                more_ = visitor.int64_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+
+            case jsoncons::bson::bson_type::timestamp_type: 
+            {
+                uint8_t buf[sizeof(uint64_t)]; 
+                std::size_t n = source_.read(buf, sizeof(uint64_t));
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != sizeof(uint64_t)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                auto val = binary::little_to_native<uint64_t>(buf, sizeof(buf));
+                more_ = visitor.uint64_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+
+            case jsoncons::bson::bson_type::int64_type: 
+            {
+                uint8_t buf[sizeof(int64_t)]; 
+                std::size_t n = source_.read(buf, sizeof(int64_t));
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != sizeof(int64_t)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                auto val = binary::little_to_native<int64_t>(buf, sizeof(buf));
+                more_ = visitor.int64_value(val, semantic_tag::none, *this, ec);
+                break;
+            }
+
+            case jsoncons::bson::bson_type::datetime_type: 
+            {
+                uint8_t buf[sizeof(int64_t)]; 
+                std::size_t n = source_.read(buf, sizeof(int64_t));
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != sizeof(int64_t)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                auto val = binary::little_to_native<int64_t>(buf, sizeof(buf));
+                more_ = visitor.int64_value(val, semantic_tag::epoch_milli, *this, ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::binary_type: 
+            {
+                uint8_t buf[sizeof(int32_t)]; 
+                std::size_t n = source_.read(buf, sizeof(int32_t));
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != sizeof(int32_t)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+                const auto len = binary::little_to_native<int32_t>(buf, sizeof(buf));
+                if (JSONCONS_UNLIKELY(len < 0))
+                {
+                    ec = bson_errc::length_is_negative;
+                    more_ = false;
+                    return;
+                }
+                uint8_t subtype;
+                n = source_.read(&subtype, 1);
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != 1))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+
+                bytes_buffer_.clear();
+                n = source_reader<Source>::read(source_, bytes_buffer_, len);
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != static_cast<std::size_t>(len)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+
+                more_ = visitor.byte_string_value(bytes_buffer_, 
+                                                  subtype, 
+                                                  *this,
+                                                  ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::decimal128_type: 
+            {
+                uint8_t buf[sizeof(uint64_t)*2]; 
+                std::size_t n = source_.read(buf, sizeof(buf));
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != sizeof(buf)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+
+                decimal128_t dec;
+                dec.low = binary::little_to_native<uint64_t>(buf, sizeof(uint64_t));
+                dec.high = binary::little_to_native<uint64_t>(buf+sizeof(uint64_t), sizeof(uint64_t));
+
+                text_buffer_.clear();
+                text_buffer_.resize(bson::decimal128_limits::buf_size);
+                auto r = bson::decimal128_to_chars(&text_buffer_[0], &text_buffer_[0]+text_buffer_.size(), dec);
+                more_ = visitor.string_value(string_view(text_buffer_.data(),static_cast<std::size_t>(r.ptr-text_buffer_.data())), semantic_tag::float128, *this, ec);
+                break;
+            }
+            case jsoncons::bson::bson_type::object_id_type: 
+            {
+                uint8_t buf[12]; 
+                std::size_t n = source_.read(buf, sizeof(buf));
+                state_stack_.back().pos += n;
+                if (JSONCONS_UNLIKELY(n != sizeof(buf)))
+                {
+                    ec = bson_errc::unexpected_eof;
+                    more_ = false;
+                    return;
+                }
+
+                oid_t oid(buf);
+                to_string(oid, text_buffer_);
+
+                more_ = visitor.string_value(text_buffer_, semantic_tag::id, *this, ec);
+                break;
+            }
+            default:
+            {
+                ec = bson_errc::unknown_type;
+                more_ = false;
+                return;
+            }
+        }
+    }
+
+    void read_cstring(std::error_code& ec)
+    {
+        uint8_t c = 0xff;
+        while (true)
+        {
+            std::size_t n = source_.read(&c, 1);
+            state_stack_.back().pos += n;
+            if (JSONCONS_UNLIKELY(n != 1))
+            {
+                ec = bson_errc::unexpected_eof;
+                more_ = false;
+                return;
+            }
+            if (c == 0)
+            {
+                break;
+            }
+            text_buffer_.push_back(c);
+        }
+    }
+
+    void read_string(std::error_code& ec)
+    {
+        uint8_t buf[sizeof(int32_t)]; 
+        std::size_t n = source_.read(buf, sizeof(int32_t));
+        state_stack_.back().pos += n;
+        if (JSONCONS_UNLIKELY(n != sizeof(int32_t)))
+        {
+            ec = bson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+        auto len = binary::little_to_native<int32_t>(buf, sizeof(buf));
+        if (JSONCONS_UNLIKELY(len < 1))
+        {
+            ec = bson_errc::string_length_is_non_positive;
+            more_ = false;
+            return;
+        }
+
+        std::size_t size = static_cast<std::size_t>(len) - static_cast<std::size_t>(1);
+        n = source_reader<Source>::read(source_, text_buffer_, size);
+        state_stack_.back().pos += n;
+
+        if (JSONCONS_UNLIKELY(n != size))
+        {
+            ec = bson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+        uint8_t c;
+        n = source_.read(&c, 1);
+        state_stack_.back().pos += n;
+        if (JSONCONS_UNLIKELY(n != 1))
+        {
+            ec = bson_errc::unexpected_eof;
+            more_ = false;
+            return;
+        }
+    }
+};
+
+}}
+
+#endif
diff --git a/include/jsoncons_ext/bson/bson_reader.hpp b/include/jsoncons_ext/bson/bson_reader.hpp
new file mode 100644
index 0000000..0079cc9
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_reader.hpp
@@ -0,0 +1,92 @@
+// Copyright 2017 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_BSON_READER_HPP
+#define JSONCONS_BSON_BSON_READER_HPP
+
+#include <string>
+#include <vector>
+#include <memory>
+#include <utility> // std::move
+#include <jsoncons/json.hpp>
+#include <jsoncons/source.hpp>
+#include <jsoncons/json_visitor.hpp>
+#include <jsoncons/config/jsoncons_config.hpp>
+#include <jsoncons_ext/bson/bson_type.hpp>
+#include <jsoncons_ext/bson/bson_error.hpp>
+#include <jsoncons_ext/bson/bson_parser.hpp>
+
+namespace jsoncons { namespace bson {
+
+template <class Source,class Allocator=std::allocator<char>>
+class basic_bson_reader 
+{
+    basic_bson_parser<Source,Allocator> parser_;
+    json_visitor& visitor_;
+public:
+    template <class Sourceable>
+    basic_bson_reader(Sourceable&& source, 
+                      json_visitor& visitor, 
+                      const Allocator alloc)
+       : basic_bson_reader(std::forward<Sourceable>(source),
+                           visitor,
+                           bson_decode_options(),
+                           alloc)
+    {
+    }
+
+    template <class Sourceable>
+    basic_bson_reader(Sourceable&& source, 
+                      json_visitor& visitor, 
+                      const bson_decode_options& options = bson_decode_options(),
+                      const Allocator alloc=Allocator())
+       : parser_(std::forward<Sourceable>(source), options, alloc),
+         visitor_(visitor)
+    {
+    }
+
+    void read()
+    {
+        std::error_code ec;
+        read(ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec,line(),column()));
+        }
+    }
+
+    void read(std::error_code& ec)
+    {
+        parser_.reset();
+        parser_.parse(visitor_, ec);
+        if (ec)
+        {
+            return;
+        }
+    }
+
+    std::size_t line() const
+    {
+        return parser_.line();
+    }
+
+    std::size_t column() const
+    {
+        return parser_.column();
+    }
+};
+
+using bson_stream_reader = basic_bson_reader<jsoncons::binary_stream_source>;
+using bson_bytes_reader = basic_bson_reader<jsoncons::bytes_source>;
+
+#if !defined(JSONCONS_NO_DEPRECATED) 
+JSONCONS_DEPRECATED_MSG("Instead, use bson_stream_reader") typedef bson_stream_reader bson_reader;
+JSONCONS_DEPRECATED_MSG("Instead, use bson_bytes_reader") typedef bson_bytes_reader bson_buffer_reader;
+#endif
+
+}}
+
+#endif
diff --git a/include/jsoncons_ext/bson/bson_type.hpp b/include/jsoncons_ext/bson/bson_type.hpp
new file mode 100644
index 0000000..cf12344
--- /dev/null
+++ b/include/jsoncons_ext/bson/bson_type.hpp
@@ -0,0 +1,44 @@
+// Copyright 2013 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_BSON_TYPE_HPP
+#define JSONCONS_BSON_BSON_TYPE_HPP
+
+#include <string>
+#include <memory>
+#include <jsoncons/config/jsoncons_config.hpp>
+
+namespace jsoncons { namespace bson {
+
+    namespace bson_type
+    {
+        const uint8_t double_type = 0x01;
+        const uint8_t string_type = 0x02; // UTF-8 string
+        const uint8_t document_type = 0x03;
+        const uint8_t array_type = 0x04;
+        const uint8_t binary_type = 0x05;
+        const uint8_t undefined_type = 0x06; // map to null
+        const uint8_t object_id_type = 0x07;
+        const uint8_t bool_type = 0x08;
+        const uint8_t datetime_type = 0x09;
+        const uint8_t null_type = 0x0a;
+        const uint8_t regex_type = 0x0b;
+        const uint8_t javascript_type = 0x0d;
+        const uint8_t symbol_type = 0x0e; // deprecated, mapped to string
+        const uint8_t javascript_with_scope_type = 0x0f; // unsupported
+        const uint8_t int32_type = 0x10;
+        const uint8_t timestamp_type = 0x11; // MongoDB internal Timestamp, uint64
+        const uint8_t int64_type = 0x12;
+        const uint8_t decimal128_type = 0x13;
+        const uint8_t min_key_type = 0xff;
+        const uint8_t max_key_type = 0x7f;
+    }
+
+    enum class bson_container_type {document, array};
+
+}}
+
+#endif
diff --git a/include/jsoncons_ext/bson/decode_bson.hpp b/include/jsoncons_ext/bson/decode_bson.hpp
new file mode 100644
index 0000000..ad352f6
--- /dev/null
+++ b/include/jsoncons_ext/bson/decode_bson.hpp
@@ -0,0 +1,201 @@
+// Copyright 2013 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_DECODE_BSON_HPP
+#define JSONCONS_BSON_DECODE_BSON_HPP
+
+#include <string>
+#include <vector>
+#include <memory>
+#include <type_traits> // std::enable_if
+#include <istream> // std::basic_istream
+#include <jsoncons/json.hpp>
+#include <jsoncons/config/jsoncons_config.hpp>
+#include <jsoncons_ext/bson/bson_reader.hpp>
+#include <jsoncons_ext/bson/bson_cursor.hpp>
+
+namespace jsoncons { 
+namespace bson {
+
+    template<class T, class Source>
+    typename std::enable_if<type_traits::is_basic_json<T>::value &&
+                            type_traits::is_byte_sequence<Source>::value,T>::type 
+    decode_bson(const Source& v, 
+                const bson_decode_options& options = bson_decode_options())
+    {
+        jsoncons::json_decoder<T> decoder;
+        auto adaptor = make_json_visitor_adaptor<json_visitor>(decoder);
+        basic_bson_reader<jsoncons::bytes_source> reader(v, adaptor, options);
+        reader.read();
+        if (!decoder.is_valid())
+        {
+            JSONCONS_THROW(ser_error(conv_errc::conversion_failed, reader.line(), reader.column()));
+        }
+        return decoder.get_result();
+    }
+
+    template<class T, class Source>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value &&
+                            type_traits::is_byte_sequence<Source>::value,T>::type 
+    decode_bson(const Source& v, 
+                const bson_decode_options& options = bson_decode_options())
+    {
+        basic_bson_cursor<bytes_source> cursor(v, options);
+        json_decoder<basic_json<char,sorted_policy>> decoder{};
+
+        std::error_code ec;
+        T val = decode_traits<T,char>::decode(cursor, decoder, ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec, cursor.context().line(), cursor.context().column()));
+        }
+        return val;
+    }
+
+    template<class T>
+    typename std::enable_if<type_traits::is_basic_json<T>::value,T>::type 
+    decode_bson(std::istream& is, 
+                const bson_decode_options& options = bson_decode_options())
+    {
+        jsoncons::json_decoder<T> decoder;
+        auto adaptor = make_json_visitor_adaptor<json_visitor>(decoder);
+        bson_stream_reader reader(is, adaptor, options);
+        reader.read();
+        if (!decoder.is_valid())
+        {
+            JSONCONS_THROW(ser_error(conv_errc::conversion_failed, reader.line(), reader.column()));
+        }
+        return decoder.get_result();
+    }
+
+    template<class T>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value,T>::type 
+    decode_bson(std::istream& is, 
+                const bson_decode_options& options = bson_decode_options())
+    {
+        basic_bson_cursor<binary_stream_source> cursor(is, options);
+        json_decoder<basic_json<char,sorted_policy>> decoder{};
+
+        std::error_code ec;
+        T val = decode_traits<T,char>::decode(cursor, decoder, ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec, cursor.context().line(), cursor.context().column()));
+        }
+        return val;
+    }
+
+    template<class T, class InputIt>
+    typename std::enable_if<type_traits::is_basic_json<T>::value,T>::type 
+    decode_bson(InputIt first, InputIt last,
+                const bson_decode_options& options = bson_decode_options())
+    {
+        jsoncons::json_decoder<T> decoder;
+        auto adaptor = make_json_visitor_adaptor<json_visitor>(decoder);
+        basic_bson_reader<binary_iterator_source<InputIt>> reader(binary_iterator_source<InputIt>(first, last), adaptor, options);
+        reader.read();
+        if (!decoder.is_valid())
+        {
+            JSONCONS_THROW(ser_error(conv_errc::conversion_failed, reader.line(), reader.column()));
+        }
+        return decoder.get_result();
+    }
+
+    template<class T, class InputIt>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value,T>::type 
+    decode_bson(InputIt first, InputIt last,
+                const bson_decode_options& options = bson_decode_options())
+    {
+        basic_bson_cursor<binary_iterator_source<InputIt>> cursor(binary_iterator_source<InputIt>(first, last), options);
+        json_decoder<basic_json<char,sorted_policy>> decoder{};
+
+        std::error_code ec;
+        T val = decode_traits<T,char>::decode(cursor, decoder, ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec, cursor.context().line(), cursor.context().column()));
+        }
+        return val;
+    }
+
+    // With leading allocator parameter
+
+    template<class T, class Source, class TempAllocator>
+    typename std::enable_if<type_traits::is_basic_json<T>::value &&
+                            type_traits::is_byte_sequence<Source>::value,T>::type 
+    decode_bson(temp_allocator_arg_t, const TempAllocator& temp_alloc,
+                const Source& v, 
+                const bson_decode_options& options = bson_decode_options())
+    {
+        json_decoder<T,TempAllocator> decoder(temp_alloc);
+        auto adaptor = make_json_visitor_adaptor<json_visitor>(decoder);
+        basic_bson_reader<jsoncons::bytes_source,TempAllocator> reader(v, adaptor, options, temp_alloc);
+        reader.read();
+        if (!decoder.is_valid())
+        {
+            JSONCONS_THROW(ser_error(conv_errc::conversion_failed, reader.line(), reader.column()));
+        }
+        return decoder.get_result();
+    }
+
+    template<class T, class Source, class TempAllocator>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value &&
+                            type_traits::is_byte_sequence<Source>::value,T>::type 
+    decode_bson(temp_allocator_arg_t, const TempAllocator& temp_alloc,
+                const Source& v, 
+                const bson_decode_options& options = bson_decode_options())
+    {
+        basic_bson_cursor<bytes_source,TempAllocator> cursor(v, options, temp_alloc);
+        json_decoder<basic_json<char,sorted_policy,TempAllocator>,TempAllocator> decoder(temp_alloc, temp_alloc);
+
+        std::error_code ec;
+        T val = decode_traits<T,char>::decode(cursor, decoder, ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec, cursor.context().line(), cursor.context().column()));
+        }
+        return val;
+    }
+
+    template<class T,class TempAllocator>
+    typename std::enable_if<type_traits::is_basic_json<T>::value,T>::type 
+    decode_bson(temp_allocator_arg_t, const TempAllocator& temp_alloc,
+                std::istream& is, 
+                const bson_decode_options& options = bson_decode_options())
+    {
+        json_decoder<T,TempAllocator> decoder(temp_alloc);
+        auto adaptor = make_json_visitor_adaptor<json_visitor>(decoder);
+        basic_bson_reader<jsoncons::binary_stream_source,TempAllocator> reader(is, adaptor, options, temp_alloc);
+        reader.read();
+        if (!decoder.is_valid())
+        {
+            JSONCONS_THROW(ser_error(conv_errc::conversion_failed, reader.line(), reader.column()));
+        }
+        return decoder.get_result();
+    }
+
+    template<class T,class TempAllocator>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value,T>::type 
+    decode_bson(temp_allocator_arg_t, const TempAllocator& temp_alloc,
+                std::istream& is, 
+                const bson_decode_options& options = bson_decode_options())
+    {
+        basic_bson_cursor<binary_stream_source,TempAllocator> cursor(is, options, temp_alloc);
+        json_decoder<basic_json<char,sorted_policy,TempAllocator>,TempAllocator> decoder(temp_alloc, temp_alloc);
+
+        std::error_code ec;
+        T val = decode_traits<T,char>::decode(cursor, decoder, ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec, cursor.context().line(), cursor.context().column()));
+        }
+        return val;
+    }
+  
+} // bson
+} // jsoncons
+
+#endif
diff --git a/include/jsoncons_ext/bson/encode_bson.hpp b/include/jsoncons_ext/bson/encode_bson.hpp
new file mode 100644
index 0000000..55f8cf5
--- /dev/null
+++ b/include/jsoncons_ext/bson/encode_bson.hpp
@@ -0,0 +1,144 @@
+// Copyright 2013 Daniel Parker
+// Distributed under the Boost license, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See https://github.com/danielaparker/jsoncons for latest version
+
+#ifndef JSONCONS_BSON_ENCODE_BSON_HPP
+#define JSONCONS_BSON_ENCODE_BSON_HPP
+
+#include <string>
+#include <vector>
+#include <memory>
+#include <type_traits> // std::enable_if
+#include <istream> // std::basic_istream
+#include <jsoncons/json.hpp>
+#include <jsoncons/config/jsoncons_config.hpp>
+#include <jsoncons_ext/bson/bson_encoder.hpp>
+#include <jsoncons_ext/bson/bson_reader.hpp>
+
+namespace jsoncons { 
+namespace bson {
+
+    template<class T, class Container>
+    typename std::enable_if<type_traits::is_basic_json<T>::value &&
+                            type_traits::is_back_insertable_byte_container<Container>::value,void>::type 
+    encode_bson(const T& j, 
+                Container& v, 
+                const bson_encode_options& options = bson_encode_options())
+    {
+        using char_type = typename T::char_type;
+        basic_bson_encoder<jsoncons::bytes_sink<Container>> encoder(v, options);
+        auto adaptor = make_json_visitor_adaptor<basic_json_visitor<char_type>>(encoder);
+        j.dump(adaptor);
+    }
+
+    template<class T, class Container>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value &&
+                            type_traits::is_back_insertable_byte_container<Container>::value,void>::type 
+    encode_bson(const T& val, 
+                Container& v, 
+                const bson_encode_options& options = bson_encode_options())
+    {
+        basic_bson_encoder<jsoncons::bytes_sink<Container>> encoder(v, options);
+        std::error_code ec;
+        encode_traits<T,char>::encode(val, encoder, json(), ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec));
+        }
+    }
+
+    template<class T>
+    typename std::enable_if<type_traits::is_basic_json<T>::value,void>::type 
+    encode_bson(const T& j, 
+                std::ostream& os, 
+                const bson_encode_options& options = bson_encode_options())
+    {
+        using char_type = typename T::char_type;
+        bson_stream_encoder encoder(os, options);
+        auto adaptor = make_json_visitor_adaptor<basic_json_visitor<char_type>>(encoder);
+        j.dump(adaptor);
+    }
+
+    template<class T>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value,void>::type 
+    encode_bson(const T& val, 
+                std::ostream& os, 
+                const bson_encode_options& options = bson_encode_options())
+    {
+        bson_stream_encoder encoder(os, options);
+        std::error_code ec;
+        encode_traits<T,char>::encode(val, encoder, json(), ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec));
+        }
+    }
+  
+    // with temp_allocator_rag
+
+    template<class T, class Container, class TempAllocator>
+    typename std::enable_if<type_traits::is_basic_json<T>::value &&
+                            type_traits::is_back_insertable_byte_container<Container>::value,void>::type 
+    encode_bson(temp_allocator_arg_t, const TempAllocator& temp_alloc,
+                const T& j, 
+                Container& v, 
+                const bson_encode_options& options = bson_encode_options())
+    {
+        using char_type = typename T::char_type;
+        basic_bson_encoder<jsoncons::bytes_sink<Container>,TempAllocator> encoder(v, options, temp_alloc);
+        auto adaptor = make_json_visitor_adaptor<basic_json_visitor<char_type>>(encoder);
+        j.dump(adaptor);
+    }
+
+    template<class T, class Container, class TempAllocator>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value &&
+                            type_traits::is_back_insertable_byte_container<Container>::value,void>::type 
+    encode_bson(temp_allocator_arg_t, const TempAllocator& temp_alloc,
+                const T& val, 
+                Container& v, 
+                const bson_encode_options& options = bson_encode_options())
+    {
+        basic_bson_encoder<jsoncons::bytes_sink<Container>,TempAllocator> encoder(v, options, temp_alloc);
+        std::error_code ec;
+        encode_traits<T,char>::encode(val, encoder, json(), ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec));
+        }
+    }
+
+    template<class T,class TempAllocator>
+    typename std::enable_if<type_traits::is_basic_json<T>::value,void>::type 
+    encode_bson(temp_allocator_arg_t, const TempAllocator& temp_alloc,
+                const T& j, 
+                std::ostream& os, 
+                const bson_encode_options& options = bson_encode_options())
+    {
+        using char_type = typename T::char_type;
+        basic_bson_encoder<jsoncons::binary_stream_sink,TempAllocator> encoder(os, options, temp_alloc);
+        auto adaptor = make_json_visitor_adaptor<basic_json_visitor<char_type>>(encoder);
+        j.dump(adaptor);
+    }
+
+    template<class T,class TempAllocator>
+    typename std::enable_if<!type_traits::is_basic_json<T>::value,void>::type 
+    encode_bson(temp_allocator_arg_t, const TempAllocator& temp_alloc,
+                const T& val, 
+                std::ostream& os, 
+                const bson_encode_options& options = bson_encode_options())
+    {
+        basic_bson_encoder<jsoncons::binary_stream_sink,TempAllocator> encoder(os, options, temp_alloc);
+        std::error_code ec;
+        encode_traits<T,char>::encode(val, encoder, json(), ec);
+        if (ec)
+        {
+            JSONCONS_THROW(ser_error(ec));
+        }
+    }
+      
+} // bson
+} // jsoncons
+
+#endif