/*
    __ _____ _____ _____
 __|  |   __|     |   | |  JSON for Modern C++ (test suite)
|  |  |__   |  |  | | | |  version 3.10.2
|_____|_____|_____|_|___|  https://github.com/nlohmann/json

Licensed under the MIT License <http://opensource.org/licenses/MIT>.
SPDX-License-Identifier: MIT
Copyright (c) 2013-2019 Niels Lohmann <http://nlohmann.me>.

Permission is hereby  granted, free of charge, to any  person obtaining a copy
of this software and associated  documentation files (the "Software"), to deal
in the Software  without restriction, including without  limitation the rights
to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

#include "doctest_compatibility.h"

#include <nlohmann/json.hpp>
using nlohmann::json;

#include <iostream>
#include <sstream>
#include <valarray>

namespace
{
struct SaxEventLogger : public nlohmann::json_sax<json>
{
    bool null() override
    {
        events.emplace_back("null()");
        return true;
    }

    bool boolean(bool val) override
    {
        events.emplace_back(val ? "boolean(true)" : "boolean(false)");
        return true;
    }

    bool number_integer(json::number_integer_t val) override
    {
        events.push_back("number_integer(" + std::to_string(val) + ")");
        return true;
    }

    bool number_unsigned(json::number_unsigned_t val) override
    {
        events.push_back("number_unsigned(" + std::to_string(val) + ")");
        return true;
    }

    bool number_float(json::number_float_t /*val*/, const std::string& s) override
    {
        events.push_back("number_float(" + s + ")");
        return true;
    }

    bool string(std::string& val) override
    {
        events.push_back("string(" + val + ")");
        return true;
    }

    bool binary(json::binary_t& val) override
    {
        std::string binary_contents = "binary(";
        std::string comma_space;
        for (auto b : val)
        {
            binary_contents.append(comma_space);
            binary_contents.append(std::to_string(static_cast<int>(b)));
            comma_space = ", ";
        }
        binary_contents.append(")");
        events.push_back(binary_contents);
        return true;
    }

    bool start_object(std::size_t elements) override
    {
        if (elements == std::size_t(-1))
        {
            events.emplace_back("start_object()");
        }
        else
        {
            events.push_back("start_object(" + std::to_string(elements) + ")");
        }
        return true;
    }

    bool key(std::string& val) override
    {
        events.push_back("key(" + val + ")");
        return true;
    }

    bool end_object() override
    {
        events.emplace_back("end_object()");
        return true;
    }

    bool start_array(std::size_t elements) override
    {
        if (elements == std::size_t(-1))
        {
            events.emplace_back("start_array()");
        }
        else
        {
            events.push_back("start_array(" + std::to_string(elements) + ")");
        }
        return true;
    }

    bool end_array() override
    {
        events.emplace_back("end_array()");
        return true;
    }

    bool parse_error(std::size_t position, const std::string& /*last_token*/, const json::exception& /*ex*/) override
    {
        events.push_back("parse_error(" + std::to_string(position) + ")");
        return false;
    }

    std::vector<std::string> events {};
};

struct SaxEventLoggerExitAfterStartObject : public SaxEventLogger
{
    bool start_object(std::size_t elements) override
    {
        if (elements == std::size_t(-1))
        {
            events.emplace_back("start_object()");
        }
        else
        {
            events.push_back("start_object(" + std::to_string(elements) + ")");
        }
        return false;
    }
};

struct SaxEventLoggerExitAfterKey : public SaxEventLogger
{
    bool key(std::string& val) override
    {
        events.push_back("key(" + val + ")");
        return false;
    }
};

struct SaxEventLoggerExitAfterStartArray : public SaxEventLogger
{
    bool start_array(std::size_t elements) override
    {
        if (elements == std::size_t(-1))
        {
            events.emplace_back("start_array()");
        }
        else
        {
            events.push_back("start_array(" + std::to_string(elements) + ")");
        }
        return false;
    }
};
} // namespace

TEST_CASE("deserialization")
{
    SECTION("successful deserialization")
    {
        SECTION("stream")
        {
            std::stringstream ss1;
            std::stringstream ss2;
            std::stringstream ss3;
            ss1 << R"(["foo",1,2,3,false,{"one":1}])";
            ss2 << R"(["foo",1,2,3,false,{"one":1}])";
            ss3 << R"(["foo",1,2,3,false,{"one":1}])";
            json j = json::parse(ss1);
            CHECK(json::accept(ss2));
            CHECK(j == json({"foo", 1, 2, 3, false, {{"one", 1}}}));

            SaxEventLogger l;
            CHECK(json::sax_parse(ss3, &l));
            CHECK(l.events.size() == 11);
            CHECK(l.events == std::vector<std::string>(
            {
                "start_array()", "string(foo)", "number_unsigned(1)",
                "number_unsigned(2)", "number_unsigned(3)", "boolean(false)",
                "start_object()", "key(one)", "number_unsigned(1)",
                "end_object()", "end_array()"
            }));
        }

        SECTION("string literal")
        {
            const auto* s = R"(["foo",1,2,3,false,{"one":1}])";
            json j = json::parse(s);
            CHECK(json::accept(s));
            CHECK(j == json({"foo", 1, 2, 3, false, {{"one", 1}}}));

            SaxEventLogger l;
            CHECK(json::sax_parse(s, &l));
            CHECK(l.events.size() == 11);
            CHECK(l.events == std::vector<std::string>(
            {
                "start_array()", "string(foo)", "number_unsigned(1)",
                "number_unsigned(2)", "number_unsigned(3)", "boolean(false)",
                "start_object()", "key(one)", "number_unsigned(1)",
                "end_object()", "end_array()"
            }));
        }

        SECTION("string_t")
        {
            json::string_t s = R"(["foo",1,2,3,false,{"one":1}])";
            json j = json::parse(s);
            CHECK(json::accept(s));
            CHECK(j == json({"foo", 1, 2, 3, false, {{"one", 1}}}));

            SaxEventLogger l;
            CHECK(json::sax_parse(s, &l));
            CHECK(l.events.size() == 11);
            CHECK(l.events == std::vector<std::string>(
            {
                "start_array()", "string(foo)", "number_unsigned(1)",
                "number_unsigned(2)", "number_unsigned(3)", "boolean(false)",
                "start_object()", "key(one)", "number_unsigned(1)",
                "end_object()", "end_array()"
            }));
        }

        SECTION("operator<<")
        {
            std::stringstream ss;
            ss << R"(["foo",1,2,3,false,{"one":1}])";
            json j;
            j << ss;
            CHECK(j == json({"foo", 1, 2, 3, false, {{"one", 1}}}));
        }

        SECTION("operator>>")
        {
            std::stringstream ss;
            ss << R"(["foo",1,2,3,false,{"one":1}])";
            json j;
            ss >> j;
            CHECK(j == json({"foo", 1, 2, 3, false, {{"one", 1}}}));
        }

        SECTION("user-defined string literal")
        {
            CHECK("[\"foo\",1,2,3,false,{\"one\":1}]"_json == json({"foo", 1, 2, 3, false, {{"one", 1}}}));
        }
    }

    SECTION("unsuccessful deserialization")
    {
        SECTION("stream")
        {
            std::stringstream ss1;
            std::stringstream ss2;
            std::stringstream ss3;
            std::stringstream ss4;
            std::stringstream ss5;
            ss1 << R"(["foo",1,2,3,false,{"one":1})";
            ss2 << R"(["foo",1,2,3,false,{"one":1})";
            ss3 << R"(["foo",1,2,3,false,{"one":1})";
            ss4 << R"(["foo",1,2,3,false,{"one":1})";
            ss5 << R"(["foo",1,2,3,false,{"one":1})";

            json _;
            CHECK_THROWS_AS(_ = json::parse(ss1), json::parse_error&);
            CHECK_THROWS_WITH(_ = json::parse(ss2),
                              "[json.exception.parse_error.101] parse error at line 1, column 29: syntax error while parsing array - unexpected end of input; expected ']'");
            CHECK(!json::accept(ss3));

            json j_error;
            CHECK_NOTHROW(j_error = json::parse(ss4, nullptr, false));
            CHECK(j_error.is_discarded());

            SaxEventLogger l;
            CHECK(!json::sax_parse(ss5, &l));
            CHECK(l.events.size() == 11);
            CHECK(l.events == std::vector<std::string>(
            {
                "start_array()", "string(foo)", "number_unsigned(1)",
                "number_unsigned(2)", "number_unsigned(3)", "boolean(false)",
                "start_object()", "key(one)", "number_unsigned(1)",
                "end_object()", "parse_error(29)"
            }));
        }

        SECTION("string")
        {
            json::string_t s = R"(["foo",1,2,3,false,{"one":1})";
            json _;
            CHECK_THROWS_AS(_ = json::parse(s), json::parse_error&);
            CHECK_THROWS_WITH(_ = json::parse(s),
                              "[json.exception.parse_error.101] parse error at line 1, column 29: syntax error while parsing array - unexpected end of input; expected ']'");
            CHECK(!json::accept(s));

            json j_error;
            CHECK_NOTHROW(j_error = json::parse(s, nullptr, false));
            CHECK(j_error.is_discarded());

            SaxEventLogger l;
            CHECK(!json::sax_parse(s, &l));
            CHECK(l.events.size() == 11);
            CHECK(l.events == std::vector<std::string>(
            {
                "start_array()", "string(foo)", "number_unsigned(1)",
                "number_unsigned(2)", "number_unsigned(3)", "boolean(false)",
                "start_object()", "key(one)", "number_unsigned(1)",
                "end_object()", "parse_error(29)"
            }));
        }

        SECTION("operator<<")
        {
            std::stringstream ss1;
            std::stringstream ss2;
            ss1 << R"(["foo",1,2,3,false,{"one":1})";
            ss2 << R"(["foo",1,2,3,false,{"one":1})";
            json j;
            CHECK_THROWS_AS(j << ss1, json::parse_error&);
            CHECK_THROWS_WITH(j << ss2,
                              "[json.exception.parse_error.101] parse error at line 1, column 29: syntax error while parsing array - unexpected end of input; expected ']'");
        }

        SECTION("operator>>")
        {
            std::stringstream ss1;
            std::stringstream ss2;
            ss1 << R"(["foo",1,2,3,false,{"one":1})";
            ss2 << R"(["foo",1,2,3,false,{"one":1})";
            json j;
            CHECK_THROWS_AS(ss1 >> j, json::parse_error&);
            CHECK_THROWS_WITH(ss2 >> j,
                              "[json.exception.parse_error.101] parse error at line 1, column 29: syntax error while parsing array - unexpected end of input; expected ']'");
        }

        SECTION("user-defined string literal")
        {
            CHECK_THROWS_AS("[\"foo\",1,2,3,false,{\"one\":1}"_json, json::parse_error&);
            CHECK_THROWS_WITH("[\"foo\",1,2,3,false,{\"one\":1}"_json,
                              "[json.exception.parse_error.101] parse error at line 1, column 29: syntax error while parsing array - unexpected end of input; expected ']'");
        }
    }

    SECTION("contiguous containers")
    {
        SECTION("directly")
        {
            SECTION("from std::vector")
            {
                std::vector<uint8_t> v = {'t', 'r', 'u', 'e'};
                CHECK(json::parse(v) == json(true));
                CHECK(json::accept(v));

                SaxEventLogger l;
                CHECK(json::sax_parse(v, &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("from std::array")
            {
                std::array<uint8_t, 5> v { {'t', 'r', 'u', 'e'} };
                CHECK(json::parse(v) == json(true));
                CHECK(json::accept(v));

                SaxEventLogger l;
                CHECK(json::sax_parse(v, &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("from array")
            {
                uint8_t v[] = {'t', 'r', 'u', 'e'}; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
                CHECK(json::parse(v) == json(true));
                CHECK(json::accept(v));

                SaxEventLogger l;
                CHECK(json::sax_parse(v, &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("from chars")
            {
                auto* v = new uint8_t[5]; // NOLINT(cppcoreguidelines-owning-memory)
                v[0] = 't';
                v[1] = 'r';
                v[2] = 'u';
                v[3] = 'e';
                v[4] = '\0';
                CHECK(json::parse(v) == json(true));
                CHECK(json::accept(v));

                SaxEventLogger l;
                CHECK(json::sax_parse(v, &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));

                delete[] v; // NOLINT(cppcoreguidelines-owning-memory)
            }

            SECTION("from std::string")
            {
                std::string v = {'t', 'r', 'u', 'e'};
                CHECK(json::parse(v) == json(true));
                CHECK(json::accept(v));

                SaxEventLogger l;
                CHECK(json::sax_parse(v, &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("from std::initializer_list")
            {
                std::initializer_list<uint8_t> v = {'t', 'r', 'u', 'e'};
                CHECK(json::parse(v) == json(true));
                CHECK(json::accept(v));

                SaxEventLogger l;
                CHECK(json::sax_parse(v, &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("empty container")
            {
                std::vector<uint8_t> v;
                json _;
                CHECK_THROWS_AS(_ = json::parse(v), json::parse_error&);
                CHECK(!json::accept(v));

                SaxEventLogger l;
                CHECK(!json::sax_parse(v, &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(1)"}));
            }
        }

        SECTION("via iterator range")
        {
            SECTION("from std::vector")
            {
                std::vector<uint8_t> v = {'t', 'r', 'u', 'e'};
                CHECK(json::parse(std::begin(v), std::end(v)) == json(true));
                CHECK(json::accept(std::begin(v), std::end(v)));

                SaxEventLogger l;
                CHECK(json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));

            }

            SECTION("from std::array")
            {
                std::array<uint8_t, 5> v { {'t', 'r', 'u', 'e'} };
                CHECK(json::parse(std::begin(v), std::end(v)) == json(true));
                CHECK(json::accept(std::begin(v), std::end(v)));

                SaxEventLogger l;
                CHECK(json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("from array")
            {
                uint8_t v[] = {'t', 'r', 'u', 'e'}; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
                CHECK(json::parse(std::begin(v), std::end(v)) == json(true));
                CHECK(json::accept(std::begin(v), std::end(v)));

                SaxEventLogger l;
                CHECK(json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("from std::string")
            {
                std::string v = {'t', 'r', 'u', 'e'};
                CHECK(json::parse(std::begin(v), std::end(v)) == json(true));
                CHECK(json::accept(std::begin(v), std::end(v)));

                SaxEventLogger l;
                CHECK(json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("from std::initializer_list")
            {
                std::initializer_list<uint8_t> v = {'t', 'r', 'u', 'e'};
                CHECK(json::parse(std::begin(v), std::end(v)) == json(true));
                CHECK(json::accept(std::begin(v), std::end(v)));

                SaxEventLogger l;
                CHECK(json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("from std::valarray")
            {
                std::valarray<uint8_t> v = {'t', 'r', 'u', 'e'};
                CHECK(json::parse(std::begin(v), std::end(v)) == json(true));
                CHECK(json::accept(std::begin(v), std::end(v)));

                SaxEventLogger l;
                CHECK(json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
            }

            SECTION("with empty range")
            {
                std::vector<uint8_t> v;
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(1)"}));
            }
        }

        // these cases are required for 100% line coverage
        SECTION("error cases")
        {
            SECTION("case 1")
            {
                std::array<std::uint8_t, 9> v = {{'\"', 'a', 'a', 'a', 'a', 'a', 'a', '\\', 'u'}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(10)"}));
            }

            SECTION("case 2")
            {
                std::array<std::uint8_t, 10> v = {{'\"', 'a', 'a', 'a', 'a', 'a', 'a', '\\', 'u', '1'}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(11)"}));
            }

            SECTION("case 3")
            {
                std::array<std::uint8_t, 17> v = {{'\"', 'a', 'a', 'a', 'a', 'a', 'a', '\\', 'u', '1', '1', '1', '1', '1', '1', '1', '1'}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(18)"}));
            }

            SECTION("case 4")
            {
                std::array<std::uint8_t, 17> v = {{'\"', 'a', 'a', 'a', 'a', 'a', 'a', 'u', '1', '1', '1', '1', '1', '1', '1', '1', '\\'}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(18)"}));
            }

            SECTION("case 5")
            {
                std::array<std::uint8_t, 3> v = {{'\"', 0x7F, 0xC1}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(3)"}));
            }

            SECTION("case 6")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xDF, 0x7F}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK_THROWS_WITH(_ = json::parse(std::begin(v), std::end(v)),
                                  "[json.exception.parse_error.101] parse error at line 1, column 4: syntax error while parsing value - invalid string: ill-formed UTF-8 byte; last read: '\"\x7f\xdf\x7f'");
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 7")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xDF, 0xC0}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 8")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xE0, 0x9F}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 9")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xEF, 0xC0}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 10")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xED, 0x7F}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 11")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xF0, 0x8F}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 12")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xF0, 0xC0}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 13")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xF3, 0x7F}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 14")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xF3, 0xC0}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 15")
            {
                std::array<std::uint8_t, 4> v = {{'\"', 0x7F, 0xF4, 0x7F}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 1);
                CHECK(l.events == std::vector<std::string>({"parse_error(4)"}));
            }

            SECTION("case 16")
            {
                std::array<std::uint8_t, 6> v = {{'{', '\"', '\"', ':', '1', '1'}};
                json _;
                CHECK_THROWS_AS(_ = json::parse(std::begin(v), std::end(v)), json::parse_error&);
                CHECK(!json::accept(std::begin(v), std::end(v)));

                json j_error;
                CHECK_NOTHROW(j_error = json::parse(std::begin(v), std::end(v), nullptr, false));
                CHECK(j_error.is_discarded());

                SaxEventLogger l;
                CHECK(!json::sax_parse(std::begin(v), std::end(v), &l));
                CHECK(l.events.size() == 4);
                CHECK(l.events == std::vector<std::string>(
                {
                    "start_object()", "key()", "number_unsigned(11)",
                    "parse_error(7)"
                }));
            }
        }
    }

    SECTION("ignoring byte-order marks")
    {
        std::string bom = "\xEF\xBB\xBF";

        SECTION("BOM only")
        {
            json _;
            CHECK_THROWS_AS(_ = json::parse(bom), json::parse_error&);
            CHECK_THROWS_WITH(_ = json::parse(bom),
                              "[json.exception.parse_error.101] parse error at line 1, column 4: syntax error while parsing value - unexpected end of input; expected '[', '{', or a literal");

            CHECK_THROWS_AS(_ = json::parse(std::istringstream(bom)), json::parse_error&);
            CHECK_THROWS_WITH(_ = json::parse(std::istringstream(bom)),
                              "[json.exception.parse_error.101] parse error at line 1, column 4: syntax error while parsing value - unexpected end of input; expected '[', '{', or a literal");

            SaxEventLogger l;
            CHECK(!json::sax_parse(bom, &l));
            CHECK(l.events.size() == 1);
            CHECK(l.events == std::vector<std::string>(
            {
                "parse_error(4)"
            }));
        }

        SECTION("BOM and content")
        {
            CHECK(json::parse(bom + "1") == 1);
            CHECK(json::parse(std::istringstream(bom + "1")) == 1);

            SaxEventLogger l1;
            SaxEventLogger l2;
            CHECK(json::sax_parse(std::istringstream(bom + "1"), &l1));
            CHECK(json::sax_parse(bom + "1", &l2));
            CHECK(l1.events.size() == 1);
            CHECK(l1.events == std::vector<std::string>(
            {
                "number_unsigned(1)"
            }));
            CHECK(l2.events.size() == 1);
            CHECK(l2.events == std::vector<std::string>(
            {
                "number_unsigned(1)"
            }));
        }

        SECTION("2 byte of BOM")
        {
            json _;
            CHECK_THROWS_AS(_ = json::parse(bom.substr(0, 2)), json::parse_error&);
            CHECK_THROWS_WITH(_ = json::parse(bom.substr(0, 2)),
                              "[json.exception.parse_error.101] parse error at line 1, column 3: syntax error while parsing value - invalid BOM; must be 0xEF 0xBB 0xBF if given; last read: '\xEF\xBB'");

            CHECK_THROWS_AS(_ = json::parse(std::istringstream(bom.substr(0, 2))), json::parse_error&);
            CHECK_THROWS_WITH(_ = json::parse(std::istringstream(bom.substr(0, 2))),
                              "[json.exception.parse_error.101] parse error at line 1, column 3: syntax error while parsing value - invalid BOM; must be 0xEF 0xBB 0xBF if given; last read: '\xEF\xBB'");

            SaxEventLogger l1;
            SaxEventLogger l2;
            CHECK(!json::sax_parse(std::istringstream(bom.substr(0, 2)), &l1));
            CHECK(!json::sax_parse(bom.substr(0, 2), &l2));
            CHECK(l1.events.size() == 1);
            CHECK(l1.events == std::vector<std::string>(
            {
                "parse_error(3)"
            }));
            CHECK(l2.events.size() == 1);
            CHECK(l2.events == std::vector<std::string>(
            {
                "parse_error(3)"
            }));
        }

        SECTION("1 byte of BOM")
        {
            json _;
            CHECK_THROWS_AS(_ = json::parse(bom.substr(0, 1)), json::parse_error&);
            CHECK_THROWS_WITH(_ = json::parse(bom.substr(0, 1)),
                              "[json.exception.parse_error.101] parse error at line 1, column 2: syntax error while parsing value - invalid BOM; must be 0xEF 0xBB 0xBF if given; last read: '\xEF'");

            CHECK_THROWS_AS(_ = json::parse(std::istringstream(bom.substr(0, 1))), json::parse_error&);
            CHECK_THROWS_WITH(_ = json::parse(std::istringstream(bom.substr(0, 1))),
                              "[json.exception.parse_error.101] parse error at line 1, column 2: syntax error while parsing value - invalid BOM; must be 0xEF 0xBB 0xBF if given; last read: '\xEF'");

            SaxEventLogger l1;
            SaxEventLogger l2;
            CHECK(!json::sax_parse(std::istringstream(bom.substr(0, 1)), &l1));
            CHECK(!json::sax_parse(bom.substr(0, 1), &l2));
            CHECK(l1.events.size() == 1);
            CHECK(l1.events == std::vector<std::string>(
            {
                "parse_error(2)"
            }));
            CHECK(l2.events.size() == 1);
            CHECK(l2.events == std::vector<std::string>(
            {
                "parse_error(2)"
            }));
        }

        SECTION("variations")
        {
            // calculate variations of each byte of the BOM to make sure
            // that the BOM and only the BOM is skipped
            for (int i0 = -1; i0 < 2; ++i0)
            {
                for (int i1 = -1; i1 < 2; ++i1)
                {
                    for (int i2 = -1; i2 < 2; ++i2)
                    {
                        // debug output for the variations
                        CAPTURE(i0)
                        CAPTURE(i1)
                        CAPTURE(i2)

                        std::string s;
                        s.push_back(static_cast<char>(bom[0] + i0));
                        s.push_back(static_cast<char>(bom[1] + i1));
                        s.push_back(static_cast<char>(bom[2] + i2));

                        if (i0 == 0 && i1 == 0 && i2 == 0)
                        {
                            // without any variation, we skip the BOM
                            CHECK(json::parse(s + "null") == json());
                            CHECK(json::parse(std::istringstream(s + "null")) == json());

                            SaxEventLogger l;
                            CHECK(json::sax_parse(s + "null", &l));
                            CHECK(l.events.size() == 1);
                            CHECK(l.events == std::vector<std::string>(
                            {
                                "null()"
                            }));
                        }
                        else
                        {
                            // any variation is an error
                            json _;
                            CHECK_THROWS_AS(_ = json::parse(s + "null"), json::parse_error&);
                            CHECK_THROWS_AS(_ = json::parse(std::istringstream(s + "null")), json::parse_error&);

                            SaxEventLogger l;
                            CHECK(!json::sax_parse(s + "null", &l));
                            CHECK(l.events.size() == 1);

                            if (i0 != 0)
                            {
                                CHECK(l.events == std::vector<std::string>(
                                {
                                    "parse_error(1)"
                                }));
                            }
                            else if (i1 != 0)
                            {
                                CHECK(l.events == std::vector<std::string>(
                                {
                                    "parse_error(2)"
                                }));
                            }
                            else
                            {
                                CHECK(l.events == std::vector<std::string>(
                                {
                                    "parse_error(3)"
                                }));
                            }
                        }
                    }
                }
            }
        }

        SECTION("preserve state after parsing")
        {
            std::istringstream s(bom + "123 456");
            json j;
            j << s;
            CHECK(j == 123);
            j << s;
            CHECK(j == 456);
        }
    }

    SECTION("SAX and early abort")
    {
        std::string s = R"([1, ["string", 43.12], null, {"key1": true, "key2": false}])";

        SaxEventLogger default_logger;
        SaxEventLoggerExitAfterStartObject exit_after_start_object;
        SaxEventLoggerExitAfterKey exit_after_key;
        SaxEventLoggerExitAfterStartArray exit_after_start_array;

        json::sax_parse(s, &default_logger);
        CHECK(default_logger.events.size() == 14);
        CHECK(default_logger.events == std::vector<std::string>(
        {
            "start_array()", "number_unsigned(1)", "start_array()",
            "string(string)", "number_float(43.12)", "end_array()", "null()",
            "start_object()", "key(key1)", "boolean(true)", "key(key2)",
            "boolean(false)", "end_object()", "end_array()"
        }));

        json::sax_parse(s, &exit_after_start_object);
        CHECK(exit_after_start_object.events.size() == 8);
        CHECK(exit_after_start_object.events == std::vector<std::string>(
        {
            "start_array()", "number_unsigned(1)", "start_array()",
            "string(string)", "number_float(43.12)", "end_array()", "null()",
            "start_object()"
        }));

        json::sax_parse(s, &exit_after_key);
        CHECK(exit_after_key.events.size() == 9);
        CHECK(exit_after_key.events == std::vector<std::string>(
        {
            "start_array()", "number_unsigned(1)", "start_array()",
            "string(string)", "number_float(43.12)", "end_array()", "null()",
            "start_object()", "key(key1)"
        }));

        json::sax_parse(s, &exit_after_start_array);
        CHECK(exit_after_start_array.events.size() == 1);
        CHECK(exit_after_start_array.events == std::vector<std::string>(
        {
            "start_array()"
        }));
    }
}

TEST_CASE_TEMPLATE("deserialization of different character types (ASCII)", T,
                   char, unsigned char, signed char,
                   wchar_t,
                   char16_t, char32_t,
                   std::uint8_t, std::int8_t,
                   std::int16_t, std::uint16_t,
                   std::int32_t, std::uint32_t)
{
    std::vector<T> v = {'t', 'r', 'u', 'e'};
    CHECK(json::parse(v) == json(true));
    CHECK(json::accept(v));

    SaxEventLogger l;
    CHECK(json::sax_parse(v, &l));
    CHECK(l.events.size() == 1);
    CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
}

TEST_CASE_TEMPLATE("deserialization of different character types (UTF-8)", T,
                   char, unsigned char, std::uint8_t)
{
    // a star emoji
    std::vector<T> v = {'"', static_cast<T>(0xe2u), static_cast<T>(0xadu), static_cast<T>(0x90u), static_cast<T>(0xefu), static_cast<T>(0xb8u), static_cast<T>(0x8fu), '"'};
    CHECK(json::parse(v).dump(-1, ' ', true) == "\"\\u2b50\\ufe0f\"");
    CHECK(json::accept(v));

    SaxEventLogger l;
    CHECK(json::sax_parse(v, &l));
    CHECK(l.events.size() == 1);
}

TEST_CASE_TEMPLATE("deserialization of different character types (UTF-16)", T,
                   char16_t, std::uint16_t)
{
    // a star emoji
    std::vector<T> v = {static_cast<T>('"'), static_cast<T>(0x2b50), static_cast<T>(0xfe0f), static_cast<T>('"')};
    CHECK(json::parse(v).dump(-1, ' ', true) == "\"\\u2b50\\ufe0f\"");
    CHECK(json::accept(v));

    SaxEventLogger l;
    CHECK(json::sax_parse(v, &l));
    CHECK(l.events.size() == 1);
}

TEST_CASE_TEMPLATE("deserialization of different character types (UTF-32)", T,
                   char32_t, std::uint32_t)
{
    // a star emoji
    std::vector<T> v = {static_cast<T>('"'), static_cast<T>(0x2b50), static_cast<T>(0xfe0f), static_cast<T>('"')};
    CHECK(json::parse(v).dump(-1, ' ', true) == "\"\\u2b50\\ufe0f\"");
    CHECK(json::accept(v));

    SaxEventLogger l;
    CHECK(json::sax_parse(v, &l));
    CHECK(l.events.size() == 1);
}