From 1d055261b4144dbf86b2658437015b15d4dd9bff Mon Sep 17 00:00:00 2001
From: Richard <q@1bpm.net>
Date: Sun, 4 Sep 2022 00:32:56 +0100
Subject: initial

---
 include/jsoncons_ext/bson/bson_encoder.hpp | 585 +++++++++++++++++++++++++++++
 1 file changed, 585 insertions(+)
 create mode 100644 include/jsoncons_ext/bson/bson_encoder.hpp

(limited to 'include/jsoncons_ext/bson/bson_encoder.hpp')

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
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