//     __ _____ _____ _____
//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
// |  |  |__   |  |  | | | |  version 3.12.0
// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT

#include "doctest_compatibility.h"

#include <nlohmann/json_view.hpp>
using nlohmann::json;
using nlohmann::ordered_json;
using nlohmann::json_document;
using nlohmann::json_view;
using nlohmann::ordered_json_document;
using nlohmann::ordered_json_view;

#include <algorithm>
#include <array>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iterator>
#include <list>
#include <map>
#include <random>
#include <sstream>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>

#ifdef JSON_HAS_CPP_17
    #include <string_view>
#endif

namespace
{
#if !defined(JSON_NOEXCEPTION)
// the exception parse() throws for a text, or "" if it accepts it
std::string parse_exception(const std::string& text, bool comments = false, bool trailing_commas = false)
{
    try
    {
        const json j = json::parse(text, nullptr, true, comments, trailing_commas);
        static_cast<void>(j);
    }
    catch (const json::exception& e)
    {
        return e.what();
    }
    return "";
}

std::string view_exception(const std::string& text, bool comments = false, bool trailing_commas = false)
{
    try
    {
        const json_document d = json_document::parse(text, true, comments, trailing_commas);
        static_cast<void>(d);
    }
    catch (const json::exception& e)
    {
        return e.what();
    }
    return "";
}
#endif

// a small deterministic generator of documents
struct generator
{
    std::mt19937 rng{5295}; // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)

    int r(int n)
    {
        return static_cast<int>(rng() % static_cast<unsigned>(n));
    }

    void str(std::string& o)
    {
        static const char* const pieces[] = {"a", "Z", " ", "\\n", "\\\"", "\\u00e9", "\\ud83d\\ude00", "\xc3\xa9", "\xe3\x81\x82", "long text beyond the first sixteen bytes"}; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
        o += '"';
        for (int n = r(5); n > 0; --n)
        {
            o += pieces[r(10)];
        }
        o += '"';
    }

    void value(std::string& o, int depth)
    {
        static const char* const scalars[] = {"0", "-1", "123456789012", "18446744073709551615", "18446744073709551616", "-9223372036854775809", // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
                                              "1.5", "-2.25e-3", "1E2", "0.1", "true", "false", "null"
                                             };
        const int k = depth > 5 ? 2 + r(4) : r(6);
        if (k < 2)
        {
            const bool object = k == 0;
            o += object ? '{' : '[';
            for (int i = r(5); i > 0; --i)
            {
                if (object)
                {
                    str(o);
                    o += r(2) == 0 ? ":" : " : ";
                }
                value(o, depth + 1);
                o += i > 1 ? ", " : "";
            }
            o += object ? '}' : ']';
        }
        else if (k < 4)
        {
            str(o);
        }
        else
        {
            o += scalars[r(13)];
        }
    }
};
} // namespace

TEST_CASE("json_view")
{
    SECTION("types and capacity")
    {
        for (const char* text :
                {"null", "true", "false", "0", "-1", "18446744073709551615", "-9223372036854775808", "18446744073709551616", "1.5",
                 "\"\"", "\"text\"", "[]", "[1,2,3]", "{}", "{\"a\":1,\"b\":2}" // NOLINT(modernize-raw-string-literal)
                })
        {
            CAPTURE(text);
            const json j = json::parse(text);
            const json_document d = json_document::parse(text);
            const json_view v = d.root();
            CHECK(v.type() == j.type());
            CHECK(v.is_null() == j.is_null());
            CHECK(v.is_boolean() == j.is_boolean());
            CHECK(v.is_number() == j.is_number());
            CHECK(v.is_number_integer() == j.is_number_integer());
            CHECK(v.is_number_unsigned() == j.is_number_unsigned());
            CHECK(v.is_number_float() == j.is_number_float());
            CHECK(v.is_string() == j.is_string());
            CHECK(v.is_array() == j.is_array());
            CHECK(v.is_object() == j.is_object());
            CHECK(v.is_binary() == j.is_binary());
            CHECK(v.is_primitive() == j.is_primitive());
            CHECK(v.is_structured() == j.is_structured());
            CHECK(!v.is_discarded());
            CHECK(static_cast<bool>(v));
            CHECK(v.size() == j.size());
            CHECK(v.empty() == j.empty());
            CHECK(v.materialize() == j);
        }

        const json_view invalid{};
        CHECK(invalid.is_discarded());
        CHECK(!static_cast<bool>(invalid));
        CHECK(invalid.type() == json::value_t::discarded);
        CHECK(invalid.size() == 0);
        CHECK(invalid.empty());
        CHECK(invalid.materialize().is_discarded());
        CHECK(invalid.source_offset() == static_cast<std::size_t>(-1));
    }

    SECTION("materialize")
    {
        generator g;
        for (int i = 0; i < 2000; ++i)
        {
            std::string text;
            g.value(text, 0);
            CAPTURE(text);
            CHECK(json_document::parse(text).root().materialize() == json::parse(text));
            // member order as ordered_json::parse keeps it
            CHECK(ordered_json_document::parse(text).root().materialize().dump() == ordered_json::parse(text).dump());
        }
        // duplicate keys: the last value, at the position of the first key
        CHECK(json_document::parse(R"({"a":1,"b":2,"a":3})").root().materialize() == json::parse(R"({"a":1,"b":2,"a":3})"));
        CHECK(ordered_json_document::parse(R"({"a":1,"b":2,"a":3})").root().materialize().dump() == R"({"a":3,"b":2})");
        // very deep nesting (iterative, as parse())
        const std::string deep = std::string(100000, '[') + std::string(100000, ']');
        CHECK(json_document::parse(deep).root().materialize() == json::parse(deep));
#if JSON_DIAGNOSTICS
        // the parents are set, so errors name the path
        const json m = json_document::parse(R"({"a":{"b":[1]}})").root().materialize();
        CHECK_THROWS_WITH_AS(m.at("a").at("b").at(0).at("x"), "[json.exception.type_error.304] (/a/b/0) cannot use at() with number", json::type_error&);
#endif
    }

    SECTION("parse errors are those of parse()")
    {
        for (const char* text :
                {
                    "", " ", "[", "]", "{", "[1,]", "{\"a\":1,}", "[1 2]", "{\"a\" 1}", "{1:2}", "tru", "nul", "fals", "truex", "-", "01", "1.", ".5", "1e",
                    "\"", "\"abc", "\"\\x\"", "\"\\u12\"", "\"\\ud800\"", "\"\\udc00\"", "\"\x01\"", "\"\xff\"", "\"\xc3\"", "[1]x", "/", "/*", "[\n  1,\n  x\n]", // NOLINT(modernize-raw-string-literal)
                    "1e400", "-1e400", "[1.7976931348623159e308]", "{\"a\":\n{\"b\": [1, 2,\n 3 x]}}"
                })
        {
            CAPTURE(text);
#if !defined(JSON_NOEXCEPTION)
            const std::string expected = parse_exception(text);
            REQUIRE(!expected.empty());
            CHECK(view_exception(text) == expected);
#endif
            CHECK(!json_document::accept(text));
            const json_document d = json_document::parse(text, false);
            CHECK(d.is_discarded());
            CHECK(d.root().is_discarded());
            CHECK(d.node_count() == 0);
        }
        // the exception types
        json_document _;
        CHECK_THROWS_AS(_ = json_document::parse("[1,"), json::parse_error&);
        CHECK_THROWS_AS(_ = json_document::parse("1e400"), json::out_of_range&);
    }

    SECTION("parse options")
    {
        for (const char* text :
                {"// c\n[1]", "[1, /* c */ 2]", "[1,]", "{\"a\":1,}", "[1,/* c */]", "/", "/* ", "[1,,]"
                })
        {
            CAPTURE(text);
            for (int options = 0; options < 4; ++options)
            {
                const bool comments = (options & 1) != 0;
                const bool trailing_commas = (options & 2) != 0;
                CHECK(json_document::accept(text, comments, trailing_commas) == json::accept(text, comments, trailing_commas));
#if !defined(JSON_NOEXCEPTION)
                CHECK(view_exception(text, comments, trailing_commas) == parse_exception(text, comments, trailing_commas));
#endif
            }
        }
    }

    SECTION("NUL and BOM")
    {
        const std::string with_nul("[1]\0garbage", 11);
        CHECK(json_document::accept(with_nul) == json::accept(with_nul));
        const std::string nul_in_comment("[1, // c\0\n2]", 12);
        CHECK(json_document::accept(nul_in_comment, true) == json::accept(nul_in_comment, true));
        CHECK(json_document::parse("\xEF\xBB\xBF[1]").root().materialize() == json::parse("\xEF\xBB\xBF[1]"));
#if !defined(JSON_NOEXCEPTION)
        CHECK(view_exception("\xEF\xBB") == parse_exception("\xEF\xBB"));
#endif
    }

    SECTION("inputs")
    {
        const std::string text = R"([1, "two", {"three": 3.5}])";
        const json expected = json::parse(text);

        // borrowed: the text must outlive the document
        const json_document borrowed = json_document::parse(text);
        CHECK(!borrowed.owns_source());
        CHECK(borrowed.source().data() == text.data());
        CHECK(borrowed.root().materialize() == expected);
        CHECK(json_document::parse(text.c_str()).root().materialize() == expected);
        CHECK(json_document::parse(R"([1, "two", {"three": 3.5}])").root().materialize() == expected);
        CHECK(json_document::parse(text.data(), text.data() + text.size()).root().materialize() == expected);
        const std::vector<char> chars(text.begin(), text.end());
        CHECK(!json_document::parse(chars).owns_source());
        CHECK(json_document::parse(chars).root().materialize() == expected);
        const std::vector<std::uint8_t> bytes(text.begin(), text.end());
        CHECK(json_document::parse(bytes).root().materialize() == expected);
#ifdef JSON_HAS_CPP_17
        const std::string_view sv = text;
        CHECK(!json_document::parse(sv).owns_source());
        CHECK(json_document::parse(sv).root().materialize() == expected);
#endif

        // owned
        std::string moved = text;
        const json_document from_rvalue = json_document::parse(std::move(moved));
        CHECK(from_rvalue.owns_source());
        CHECK(from_rvalue.root().materialize() == expected);
        CHECK(json_document::parse(std::vector<char>(text.begin(), text.end())).owns_source());
        CHECK(json_document::parse_copy(text).owns_source());
        CHECK(json_document::parse_copy(text).root().materialize() == expected);
        std::istringstream stream(text);
        const json_document from_stream = json_document::parse(stream);
        CHECK(from_stream.owns_source());
        CHECK(from_stream.root().materialize() == expected);
        const std::list<char> list(text.begin(), text.end());
        CHECK(json_document::parse(list.begin(), list.end()).owns_source());
        CHECK(json_document::parse(list.begin(), list.end()).root().materialize() == expected);

        // iterator pairs: pointers are borrowed, and so are contiguous library
        // iterators where the input adapter detects them (C++20)
        CHECK(!json_document::parse(text.data(), text.data() + text.size()).owns_source());
        const bool contiguous = nlohmann::detail::iterator_input_adapter<std::vector<char>::const_iterator>::supports_bulk_scan;
        const json_document from_iterators = json_document::parse(chars.cbegin(), chars.cend());
        CHECK(from_iterators.owns_source() != contiguous);
        CHECK((from_iterators.source().data() == chars.data()) == contiguous);
        CHECK(from_iterators.root().materialize() == expected);
        const std::string padded = "x" + text + "x";
        CHECK(json_document::parse(padded.begin() + 1, padded.end() - 1).root().materialize() == expected);
        CHECK(json_document::parse(chars.cbegin(), chars.cbegin(), false).is_discarded());
        const std::wstring wide = L"[\"\u00e4\u20ac\", 1]";
        CHECK(json_document::parse(wide).root().materialize() == json::parse(wide));
        CHECK(json_document::parse(static_cast<const char*>(nullptr), false).is_discarded());
        CHECK(json_document::parse("", false).is_discarded());
    }

    SECTION("document lifetime and reuse")
    {
        json_document d;
        CHECK(d.is_discarded());
        CHECK(d.root().is_discarded());
        CHECK(d.node_count() == 0);
        CHECK(d.memory_usage() == 0);
        CHECK(d.source().empty());

        const std::string a = "[1,2,3]";
        const std::string b = "{\"x\":[true]}";
        d.read(a);
        CHECK(d.node_count() == 4);
        CHECK(d.root().materialize() == json::parse(a));
        d.read(b);
        CHECK(d.node_count() == 4);
        CHECK(d.root().materialize() == json::parse(b));
        d.read("[", false);
        CHECK(d.is_discarded());

        // views stay valid when the document moves
        json_document first = json_document::parse(a);
        const json_view root = first.root();
        const json_document second = std::move(first);
        CHECK(root.materialize() == json::parse(a));
        CHECK(second.root().materialize() == json::parse(a));
    }

    SECTION("memory")
    {
        std::string big = "[";
        for (int i = 0; i < 10000; ++i)
        {
            big += (i != 0 ? ",\"" : "\"") + std::to_string(i) + "\"";
        }
        big += ']';
        json_document d = json_document::parse(big);
        CHECK(d.node_count() == 10001);
        const std::size_t before = d.memory_usage();
        d.shrink_to_fit(); // (invalidates views, like std::vector::shrink_to_fit)
        CHECK(d.memory_usage() <= before);
        CHECK(d.node_count() == 10001);
        CHECK(d.root().materialize() == json::parse(big));
        CHECK(d.root().size() == 10000);
        d.shrink_to_fit(); // nothing left to release

        // after reading a smaller text, both the index and the decoded strings
        // shrink, and the strings are found in their new place
        std::string escaped = "[";
        for (int i = 0; i < 1000; ++i)
        {
            escaped += (i != 0 ? ",\"a\\n" : "\"a\\n") + std::to_string(i) + "\"";
        }
        escaped += ']';
        json_document reused = json_document::parse(escaped);
        const std::string smaller = "[\"x\\ty\", [true, \"\\u00e4\"]]"; // NOLINT(modernize-raw-string-literal)
        reused.read(smaller);
        const std::size_t grown = reused.memory_usage();
        reused.shrink_to_fit();
        CHECK(reused.memory_usage() < grown);
        CHECK(reused.root().materialize() == json::parse(smaller));

        // an empty document has nothing to release
        json_document empty;
        empty.shrink_to_fit();
        CHECK(empty.memory_usage() == 0);

        // a small document stays in the storage block of the header
        json_document small = json_document::parse("[1,[2,3],{\"a\":\"b\\n\"}]"); // NOLINT(modernize-raw-string-literal)
        small.shrink_to_fit();
        CHECK(small.root().materialize() == json::parse("[1,[2,3],{\"a\":\"b\\n\"}]"));
    }

    SECTION("source offsets")
    {
        const std::string text = R"(  {"key": "value", "escaped": "a\nb", "n": 42})";
        const json_document d = json_document::parse(text);
        CHECK(d.root().source_offset() == 2);
        CHECK(d.root()["key"].source_offset() == text.find("value"));
        CHECK(d.root()["escaped"].source_offset() == static_cast<std::size_t>(-1));
        CHECK(d.root()["n"].source_offset() == text.find("42"));
    }
}

namespace
{
#if !defined(JSON_NOEXCEPTION)
// the exception a call throws, or "" if it throws none
template<typename F>
std::string exception_of(F f)
{
    try
    {
        f();
    }
    catch (const json::exception& e)
    {
        return e.what();
    }
    return "";
}
#endif

// compares a view with the ordered_json value materialize() gives for it:
// types, sizes, elements and members (by index, key, and iteration), in
// document order; duplicate keys are found as their first occurrence
void check_access(const ordered_json_view& v, const ordered_json& j)
{
    REQUIRE(v.type() == j.type());
    CHECK(std::string(v.type_name()) == j.type_name());
    if (v.is_array())
    {
        REQUIRE(v.size() == j.size());
        std::size_t i = 0;
        for (const ordered_json_view e : v)
        {
            CHECK(v[i].materialize() == e.materialize());
            CHECK(v.at(i).materialize() == e.materialize());
            check_access(e, j[i]);
            ++i;
        }
        CHECK(i == v.size());
        CHECK(!v[v.size()]);
        std::size_t index = 0;
        for (const auto& item : v.items())
        {
            CHECK(item.key() == std::to_string(index));
            CHECK(item.value().materialize() == j[index]);
            ++index;
        }
        if (!v.empty())
        {
            CHECK(v.front().materialize() == j.front());
            CHECK(v.back().materialize() == j.back());
        }
    }
    else if (v.is_object())
    {
        std::vector<std::string> keys; // first occurrences, in order
        std::size_t members = 0;
        for (auto it = v.begin(); it != v.end(); ++it)
        {
            ++members;
            const std::string key(it.key().data(), it.key().size());
            CHECK(v.contains(key));
            CHECK(v.count(key) == 1);
            if (std::find(keys.begin(), keys.end(), key) != keys.end())
            {
                continue; // a duplicate: lookups find the first one
            }
            keys.push_back(key);
            CHECK(v.find(key) == it);
            CHECK(v[key].materialize() == it->materialize());
            CHECK(v.at(key).materialize() == it.value().materialize());
            CHECK(v[key.c_str()].materialize() == (*it).materialize());
        }
        CHECK(members == v.size());
        REQUIRE(keys.size() == j.size());
        std::size_t k = 0;
        for (const auto& member : j.items())
        {
            CHECK(keys[k++] == member.key());
        }
        if (keys.size() == members)
        {
            // no duplicates: the values are those of the object
            for (const auto& key : keys)
            {
                check_access(v[key], j[key]);
            }
            if (!v.empty())
            {
                CHECK(v.front().materialize() == j.front());
                CHECK(v.back().materialize() == j.back());
            }
        }
        CHECK(!v["not a key in the generated documents"]);
        CHECK(v.find("not a key in the generated documents") == v.end());
    }
    else
    {
        // a primitive is a range of one element; null is empty
        CHECK(static_cast<std::size_t>(std::distance(v.begin(), v.end())) == (v.is_null() ? 0u : 1u));
        if (!v.is_null())
        {
            CHECK((*v.begin()).materialize() == j);
            CHECK(v.front().materialize() == j);
            CHECK(v.back().materialize() == j);
        }
    }
}
} // namespace

TEST_CASE("json_view element access and iteration")
{
    SECTION("generated documents")
    {
        generator g;
        for (int i = 0; i < 2000; ++i)
        {
            std::string text;
            g.value(text, 0);
            CAPTURE(text);
            const ordered_json_document d = ordered_json_document::parse(text);
            check_access(d.root(), ordered_json::parse(text));
        }
    }

    SECTION("keys")
    {
        // keys of every length around the 2/4/8/16-byte loads, with escapes
        std::string text = "{";
        std::vector<std::string> keys = {"", "x"};
        for (std::size_t n = 1; n <= 40; ++n)
        {
            keys.emplace_back(n, 'k');
            keys.push_back(std::string(n, 'k') + "x");
            keys.push_back("x" + std::string(n, 'k'));
        }
        for (std::size_t i = 0; i < keys.size(); ++i)
        {
            text += (i != 0 ? ",\"" : "\"") + keys[i] + "\":" + std::to_string(i);
        }
        text += ",\"esc\\u0061ped\":\"escaped key\"}"; // NOLINT(modernize-raw-string-literal)
        const json_document d = json_document::parse(text);
        const json_view root = d.root();
        for (std::size_t i = 0; i < keys.size(); ++i)
        {
            CAPTURE(keys[i]);
            CHECK(root[keys[i]].materialize() == i);
            CHECK(root.at(keys[i]).materialize() == i);
            CHECK(root.find(keys[i]).key() == keys[i]);
            CHECK(!root.contains(keys[i] + "y"));
        }
        CHECK(root["escaped"].materialize() == "escaped key");
        CHECK(!root.contains("esc\\u0061ped"));
#ifdef JSON_HAS_CPP_17
        CHECK(root[std::string_view("kkk")].materialize() == root["kkk"].materialize());
#endif
    }

    SECTION("duplicate keys: lookups find the first member, iteration all")
    {
        const json_document d = json_document::parse(R"({"a":1,"b":2,"a":3})");
        const json_view v = d.root();
        CHECK(v.size() == 3);
        CHECK(v["a"].materialize() == 1);
        CHECK(v.at("a").materialize() == 1);
        CHECK(v.find("a") == v.begin());
        CHECK(v.count("a") == 1);
        std::string order;
        for (auto it = v.begin(); it != v.end(); ++it)
        {
            order += std::string(it.key().data(), it.key().size()) + it->materialize().dump();
        }
        CHECK(order == "a1b2a3");
        CHECK(v.back().materialize() == 3);
        CHECK(v.materialize() == json::parse(R"({"a":1,"b":2,"a":3})")); // the last value, as parse()
    }

    SECTION("errors are those of const basic_json")
    {
        for (const char* text :
                {"null", "true", "42", "-1", "1.5", "\"s\"", "[]", "[1,2]", "{}", "{\"a\":1}"
                })
        {
            CAPTURE(text);
            const json_document d = json_document::parse(text);
            const json_view v = d.root();
            const json j = v.materialize();
#if !defined(JSON_NOEXCEPTION)
            if (!j.is_object())
            {
                CHECK(exception_of([&] { static_cast<void>(v["a"]); }) == exception_of([&] { static_cast<void>(j["a"]); }));
            }
            if (!j.is_array())
            {
                CHECK(exception_of([&] { static_cast<void>(v[0]); }) == exception_of([&] { static_cast<void>(j[0]); }));
            }
            CHECK(exception_of([&] { static_cast<void>(v.at("a")); }) == exception_of([&] { static_cast<void>(j.at("a")); }));
            CHECK(exception_of([&] { static_cast<void>(v.at("missing")); }) == exception_of([&] { static_cast<void>(j.at("missing")); }));
            CHECK(exception_of([&] { static_cast<void>(v.at(0)); }) == exception_of([&] { static_cast<void>(j.at(0)); }));
            CHECK(exception_of([&] { static_cast<void>(v.at(5)); }) == exception_of([&] { static_cast<void>(j.at(5)); }));
            if (!(j.is_object() && j.empty())) // (key() of an end iterator)
            {
                CHECK(exception_of([&] { static_cast<void>(v.begin().key()); }) == exception_of([&] { static_cast<void>(j.begin().key()); }));
            }
            if (!j.empty() || j.is_null())
            {
                CHECK(exception_of([&] { static_cast<void>(v.front()); }) == exception_of([&] { static_cast<void>(j.front()); }));
                CHECK(exception_of([&] { static_cast<void>(v.back()); }) == exception_of([&] { static_cast<void>(j.back()); }));
            }
#endif
            CHECK(v.contains("a") == j.contains("a"));
            CHECK(v.count("a") == j.count("a"));
            CHECK((v.find("a") == v.end()) == (j.find("a") == j.end())); // NOLINT(readability-container-contains): find() is what is tested
        }

        // where basic_json has undefined behavior, the view answers safely
        const json_document d = json_document::parse(R"({"a":[]})");
        CHECK(!d.root()["b"]);
        CHECK(!d.root()["a"][0]);
        CHECK_THROWS_WITH_AS(d.root()["a"].front(), "[json.exception.invalid_iterator.214] cannot get value", json::invalid_iterator&);
        CHECK_THROWS_WITH_AS(d.root()["a"].back(), "[json.exception.invalid_iterator.214] cannot get value", json::invalid_iterator&);
        const json_view invalid{};
        CHECK(invalid.begin() == invalid.end());
        CHECK(std::string(invalid.type_name()) == "discarded");
        CHECK_THROWS_WITH_AS(invalid["a"], "[json.exception.type_error.305] cannot use operator[] with a string argument with discarded", json::type_error&);
    }

    SECTION("iterators")
    {
        const json_document d = json_document::parse(R"({"x":[1,{"y":2}],"z":null})");
        const json_view v = d.root();
        json_view::iterator it = v.begin();
        CHECK(it.is_object_iterator());
        CHECK(it->is_array());
        CHECK(it->size() == 2);
        const json_view::iterator previous = it++;
        CHECK(previous.key() == "x");
        CHECK(it.key() == "z");
        CHECK(it.value().is_null());
        CHECK(++it == v.end());
        CHECK(v.cbegin() == v.begin());
        CHECK(v.cend() == v.end());
        CHECK(!v["x"].begin().is_object_iterator());
        CHECK(json_view::iterator() == json_view::iterator());
        // standard algorithms
        CHECK(std::count_if(v["x"].begin(), v["x"].end(), [](const json_view & e)
        {
            return e.is_object();
        }) == 1);
    }

    SECTION("items")
    {
        const json_document d = json_document::parse(R"({"a":1,"b":[true,false]})");
        std::string keys;
        for (const auto& item : d.root().items())
        {
            keys += std::string(item.key().data(), item.key().size());
            CHECK(item.value().materialize() == d.root()[item.key()].materialize());
        }
        CHECK(keys == "ab");
        auto items = d.root()["b"].items();
        auto first = items.begin();
        CHECK((*first++).key() == "0");
        CHECK((*first).key() == "1");
        CHECK(++first == items.end());
#ifdef JSON_HAS_CPP_17
        std::string pairs;
        for (const auto [key, value] : d.root().items())
        {
            pairs += std::string(key) + "=" + value.materialize().dump() + ";";
        }
        CHECK(pairs == "a=1;b=[true,false];");
        static_assert(std::tuple_size<json_view::item>::value == 2, "");
        static_assert(std::is_same<std::tuple_element<1, json_view::item>::type, json_view>::value, "");
#endif
    }
}

namespace
{
#if !defined(JSON_NOEXCEPTION)
// an exception message without the context that basic_json adds with
// JSON_DIAGNOSTICS ("(/path) ") and JSON_DIAGNOSTIC_POSITIONS ("(bytes 1-2) ");
// the view's exceptions have no such context
std::string without_path(std::string msg)
{
    for (const char* prefix :
            {"] (/", "] (bytes "
            })
    {
        const std::size_t open = msg.find(prefix);
        if (open != std::string::npos)
        {
            msg.erase(open + 2, msg.find(") ", open) + 2 - (open + 2));
        }
    }
    return msg;
}
#endif

// the bits of a float, to compare values bit for bit
std::uint64_t bits(double x)
{
    std::uint64_t r = 0;
    std::memcpy(&r, &x, sizeof(r));
    return r;
}

std::uint32_t bits(float x)
{
    std::uint32_t r = 0;
    std::memcpy(&r, &x, sizeof(r));
    return r;
}

bool has_duplicate_keys(const ordered_json_view& v)
{
    if (v.is_object() && v.size() != v.materialize().size())
    {
        return true;
    }
    return std::any_of(v.begin(), v.end(), [](const ordered_json_view e)
    {
        return e.is_structured() && has_duplicate_keys(e);
    });
}

// compares the conversions of a view with those of ordered_json
void check_values(const ordered_json_view& v, const ordered_json& j, const std::string& text)
{
    CHECK(v.get<ordered_json>() == j);
    switch (j.type())
    {
        case json::value_t::number_integer:
        case json::value_t::number_unsigned:
        case json::value_t::number_float:
        {
            // (converting a float out of range of the target type is undefined)
            if (j.is_number_unsigned())
            {
                CHECK(v.get<std::uint64_t>() == j.get<std::uint64_t>());
            }
            else if (j.is_number_integer())
            {
                CHECK(v.get<std::int64_t>() == j.get<std::int64_t>());
            }
            CHECK(bits(v.get<double>()) == bits(j.get<double>()));
            if (std::abs(j.get<double>()) < 1e9)
            {
                CHECK(v.get<int>() == j.get<int>());
            }
            const auto token = v.number_token();
            CHECK(text.compare(v.source_offset(), token.size(), token.data(), token.size()) == 0);
            break;
        }
        case json::value_t::string:
            CHECK(v.get<std::string>() == j.get<std::string>());
            CHECK(std::string(v.get_string().data(), v.get_string().size()) == j.get<std::string>());
            break;
        case json::value_t::boolean:
            CHECK(v.get<bool>() == j.get<bool>());
            CHECK(v.get<int>() == j.get<int>());
            break;
        case json::value_t::null:
            CHECK(v.get<std::nullptr_t>() == nullptr);
            break;
        case json::value_t::array:
            CHECK(v.get<std::vector<ordered_json>>() == j.get<std::vector<ordered_json>>());
            break;
        case json::value_t::object:
            CHECK((v.get<std::map<std::string, ordered_json>>() == j.get<std::map<std::string, ordered_json>>()));
            break;
        case json::value_t::binary:
        case json::value_t::discarded:
        default:
            break;
    }

#if !defined(JSON_NOEXCEPTION)
    // conversions to the wrong type throw what basic_json throws
    if (!j.is_number())
    {
        CHECK(exception_of([&] { static_cast<void>(v.get<int>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<int>()); })));
    }
    CHECK(exception_of([&] { static_cast<void>(v.get<bool>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<bool>()); })));
    CHECK(exception_of([&] { static_cast<void>(v.get<std::string>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<std::string>()); })));
    CHECK(exception_of([&] { static_cast<void>(v.get<std::nullptr_t>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<std::nullptr_t>()); })));
    if (!j.is_array())
    {
        CHECK(exception_of([&] { static_cast<void>(v.get<std::vector<int>>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<std::vector<int>>()); })));
    }
    if (!j.is_object())
    {
        CHECK(exception_of([&] { static_cast<void>(v.get<std::map<std::string, int>>()); }) == without_path(exception_of([&] { static_cast<void>(j.get<std::map<std::string, int>>()); })));
    }
#endif

    if (v.is_array())
    {
        std::size_t i = 0;
        for (const ordered_json_view e : v)
        {
            check_values(e, j[i++], text);
        }
    }
    else if (v.is_object())
    {
        for (auto it = v.begin(); it != v.end(); ++it)
        {
            const std::string key(it.key().data(), it.key().size());
            if (v.size() == j.size()) // (no duplicate keys)
            {
                check_values(it.value(), j[key], text);
            }
        }
    }
}

struct record
{
    std::string name{}; // NOLINT(readability-redundant-member-init)
    int count = 0;
};

void from_json(const json& j, record& r)
{
    j.at("name").get_to(r.name);
    j.at("count").get_to(r.count);
}
} // namespace

TEST_CASE("json_view values")
{
    SECTION("generated documents")
    {
        generator g;
        for (int i = 0; i < 2000; ++i)
        {
            std::string text;
            g.value(text, 0);
            CAPTURE(text);
            const ordered_json_document d = ordered_json_document::parse(text);
            check_values(d.root(), ordered_json::parse(text), text);
        }
    }

    SECTION("floats are converted as parse() converts them")
    {
        std::mt19937_64 rng(5295); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
        std::vector<std::string> tokens = {"0.1", "-0.0", "1e308", "1.7976931348623157e308", "2.2250738585072011e-308", "4.9e-324", "5e-324",
                                           "0.1000000000000000055511151231257827021181583404541015625", "123456789012345678901234567890",
                                           "9007199254740993", "1.00000000000000011102230246251565404236316680908203125", "7.2057594037927933e16",
                                           // around the limits of the conversion from the digit layout: 19 and 20
                                           // digits, and those of Clinger's fast path (2^53, 10^22)
                                           "1234567890.123456789", "1234567890.1234567891", "0.0000000000000000001", "123456789012345678.9",
                                           "9007199254740992.0", "9007199254740993.0", "9007199254740994.0", "1.5e22", "1.5e23", "15e-22", "15e-23",
                                           "1e-400", "0.0e0", "-0.0e-5", "12E+3", "12e-0"
                                          };
        for (int i = 0; i < 20000; ++i)
        {
            const std::uint64_t bits = rng();
            double d = 0;
            std::memcpy(&d, &bits, sizeof(d));
            if (!std::isfinite(d))
            {
                continue;
            }
            std::array<char, 400> buf{};
            switch (i % 5) // NOLINT(hicpp-multiway-paths-covered)
            {
                case 0:
                    std::snprintf(buf.data(), buf.size(), "%.17g", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                    break;
                case 1:
                    std::snprintf(buf.data(), buf.size(), "%.15g", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                    break;
                case 2:
                    std::snprintf(buf.data(), buf.size(), "%.3e", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                    break;
                case 3:
                    std::snprintf(buf.data(), buf.size(), "%.25g", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                    break;
                default:
                    std::snprintf(buf.data(), buf.size(), "%.0f", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                    break;
            }
            tokens.emplace_back(buf.data());
        }
        using json_float = nlohmann::basic_json<std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t, float>;
        for (const auto& token : tokens)
        {
            CAPTURE(token);
            const std::string text = "[" + token + "]";
            const double b = json::parse(text)[0].get<double>();
            CHECK(bits(json_document::parse(text).root()[0].get<double>()) == bits(b));
            if (std::abs(b) < 1e38)
            {
                CHECK(bits(nlohmann::basic_json_document<json_float>::parse(text).root()[0].get<float>()) == bits(json_float::parse(text)[0].get<float>()));
            }
        }
    }

    SECTION("number tokens")
    {
        const json_document d = json_document::parse(R"([1.50, 1E2, -0, 123456789012345678901234567890, -12, 7, "x"])");
        const json_view v = d.root();
        CHECK(v[0].number_token() == "1.50");
        CHECK(v[1].number_token() == "1E2");
        CHECK(v[2].number_token() == "-0");
        CHECK(v[3].number_token() == "123456789012345678901234567890");
        CHECK(v[4].number_token() == "-12");
        CHECK(v[5].number_token() == "7");
        CHECK_THROWS_WITH_AS(v[6].number_token(), "[json.exception.type_error.302] type must be number, but is string", json::type_error&);
        CHECK_THROWS_WITH_AS(v.get_string(), "[json.exception.type_error.302] type must be string, but is array", json::type_error&);
    }

    SECTION("conversions")
    {
        const std::string text = R"({"name": "widget", "count": 3, "tags": ["a", "b\n"], "sizes": {"s": 1, "m": 2}, "pair": [1, "x"]})";
        const json_document d = json_document::parse(text);
        const json_view v = d.root();
        const json j = json::parse(text);

        // user types with from_json, and other types, through basic_json
        const record r = v.get<record>();
        CHECK(r.name == "widget");
        CHECK(r.count == 3);
        CHECK((v["pair"].get<std::pair<int, std::string>>() == j["pair"].get<std::pair<int, std::string>>()));
        CHECK(v["tags"].get<std::list<std::string>>() == j["tags"].get<std::list<std::string>>());
        CHECK((v["sizes"].get<std::unordered_map<std::string, int>>() == j["sizes"].get<std::unordered_map<std::string, int>>()));
        CHECK(v["tags"].get<std::vector<std::string>>() == std::vector<std::string> {"a", "b\n"});

        // views of the elements
        const auto views = v["tags"].get<std::vector<json_view>>();
        CHECK(views.size() == 2);
        CHECK(views[1].get_string() == "b\n");
        const auto members = v.get<std::map<std::string, json_view>>();
        CHECK(members.at("count").get<int>() == 3);
        CHECK(v.get<json_view>()["name"].get_string() == "widget");

        // strings without a copy point into the source text
        CHECK(v["name"].get_string().data() == text.data() + text.find("widget"));
#ifdef JSON_HAS_CPP_17
        CHECK(v["name"].get<std::string_view>() == "widget");
#endif

        std::string name;
        int count = 0;
        CHECK(&v["name"].get_to(name) == &name);
        v["count"].get_to(count);
        CHECK(name == "widget");
        CHECK(count == 3);

        // a duplicate key: the last value, as parse()
        CHECK((json_document::parse(R"({"a":1,"a":2})").root().get<std::map<std::string, int>>() == std::map<std::string, int> {{"a", 2}}));

        const json_view invalid{};
        CHECK_THROWS_WITH_AS(invalid.get<int>(), "[json.exception.type_error.302] type must be number, but is discarded", json::type_error&);
        CHECK(invalid.get<json>().is_discarded());
    }

    SECTION("value")
    {
        const json_document d = json_document::parse(R"({"n": 1, "s": "text", "o": {"x": [10, 20]}})");
        const json_view v = d.root();
        const json j = v.materialize();
        CHECK(v.value("n", 0) == j.value("n", 0));
        CHECK(v.value("missing", 42) == j.value("missing", 42));
        CHECK(v.value("s", "default") == j.value("s", "default"));
        CHECK(v.value("missing", "default") == j.value("missing", "default"));
        CHECK(v.value(std::string("n"), 2.5) == j.value(std::string("n"), 2.5));
        CHECK(v.value(json::json_pointer("/o/x/1"), 0) == j.value(json::json_pointer("/o/x/1"), 0));
        CHECK(v.value(json::json_pointer("/o/x/5"), 0) == j.value(json::json_pointer("/o/x/5"), 0));
        CHECK(v.value(json::json_pointer("/o/y"), "none") == j.value(json::json_pointer("/o/y"), "none"));
        // with a JSON pointer, arrays can be asked as well
        CHECK(v["o"]["x"].value(json::json_pointer("/1"), 0) == j["o"]["x"].value(json::json_pointer("/1"), 0));
        CHECK(v["o"]["x"].value(json::json_pointer("/7"), 3) == j["o"]["x"].value(json::json_pointer("/7"), 3));
#if !defined(JSON_NOEXCEPTION)
        CHECK(exception_of([&] { static_cast<void>(v["o"]["x"].value("k", 0)); }) == without_path(exception_of([&] { static_cast<void>(j["o"]["x"].value("k", 0)); })));
        CHECK(exception_of([&] { static_cast<void>(v.value("s", 0)); }) == without_path(exception_of([&] { static_cast<void>(j.value("s", 0)); })));
        CHECK(exception_of([&] { static_cast<void>(v["n"].value("x", 0)); }) == without_path(exception_of([&] { static_cast<void>(j["n"].value("x", 0)); })));
        CHECK(exception_of([&] { static_cast<void>(v["n"].value(json::json_pointer("/x"), 0)); }) == without_path(exception_of([&] { static_cast<void>(j["n"].value(json::json_pointer("/x"), 0)); })));
#endif
    }
}

TEST_CASE("json_view JSON pointers")
{
    SECTION("every value of generated documents")
    {
        generator g;
        for (int i = 0; i < 1000; ++i)
        {
            std::string text;
            g.value(text, 0);
            const ordered_json_document d = ordered_json_document::parse(text);
            if (has_duplicate_keys(d.root()))
            {
                continue;
            }
            CAPTURE(text);
            const ordered_json j = ordered_json::parse(text);
            const ordered_json flat = j.flatten();
            for (const auto& leaf : flat.items())
            {
                // the leaf and each of its parents
                for (ordered_json::json_pointer p(leaf.key());; p = p.parent_pointer())
                {
                    CAPTURE(p.to_string());
                    CHECK(d.root()[p].materialize() == j[p]);
                    CHECK(d.root().at(p).materialize() == j.at(p));
                    CHECK(d.root().contains(p));
                    if (p.empty())
                    {
                        break;
                    }
                }
            }
        }
    }

#if !defined(JSON_NOEXCEPTION)
    SECTION("errors are those of basic_json")
    {
        const std::string text = R"({"a": [1, {"b": null}], "c": "s", "": {"": 0}, "a~b": 1, "c/d": 2})";
        const json_document d = json_document::parse(text);
        const json_view v = d.root();
        const json j = v.materialize();
        for (const char* pointer :
                {"", "/", "//", "/a", "/a/0", "/a/1/b", "/a/-", "/a/01", "/a/00", "/a/1a", "/a/a", "/a/", "/a/2", "/a/99", "/a/99999999999999999999",
                 "/a/18446744073709551615", "/a/-1", "/a/+1", "/a/ 1", "/x", "/c/x", "/a/0/x", "/a/1/b/c", "/a~0b", "/c~1d", "/c~1d/x", "/a/1/-"
                })
        {
            CAPTURE(pointer);
            const json::json_pointer p(pointer);
            const std::string at_error = without_path(exception_of([&] { static_cast<void>(j.at(p)); }));
            CHECK(exception_of([&] { static_cast<void>(v.at(p)); }) == at_error);
            if (at_error.empty())
            {
                CHECK(v.at(p).materialize() == j.at(p));
                CHECK(v[p].materialize() == j[p]);
            }
            else if (at_error.find("out_of_range.401") != std::string::npos || at_error.find("out_of_range.403") != std::string::npos) // NOLINT(abseil-string-find-str-contains)
            {
                // undefined behavior for const basic_json::operator[]
                CHECK(!v[p]);
            }
            else
            {
                CHECK(exception_of([&] { static_cast<void>(v[p]); }) == without_path(exception_of([&] { static_cast<void>(j[p]); })));
            }
            // (basic_json::contains() throws out_of_range.404 for an empty
            // array index token, although it is not meant to throw; the view
            // answers false)
            const std::string contains_error = exception_of([&]
            {
                const bool found = j.contains(p);
                static_cast<void>(found);
            });
            CHECK(v.contains(p) == (contains_error.empty() && j.contains(p)));
            CHECK(exception_of([&] { static_cast<void>(v.value(p, 5)); }) == without_path(exception_of([&] { static_cast<void>(j.value(p, 5)); })));
        }
    }
#endif
}

TEST_CASE("json_view dump")
{
    SECTION("the output of ordered_json::dump()")
    {
        generator g;
        for (int i = 0; i < 2000; ++i)
        {
            std::string text;
            g.value(text, 0);
            const ordered_json_document d = ordered_json_document::parse(text);
            if (has_duplicate_keys(d.root()))
            {
                continue;
            }
            CAPTURE(text);
            const ordered_json j = ordered_json::parse(text);
            for (const int indent :
                    {
                        -1, 0, 2
                    })
            {
                for (const bool ensure_ascii :
                        {
                            false, true
                        })
                {
                    CHECK(d.root().dump(indent, i % 2 == 0 ? ' ' : '\t', ensure_ascii) == j.dump(indent, i % 2 == 0 ? ' ' : '\t', ensure_ascii));
                }
            }
            // also of each element
            for (const ordered_json_view e : d.root())
            {
                CHECK(e.dump() == e.materialize().dump());
            }
        }
    }

    SECTION("strings")
    {
        const std::string text = R"(["plain", "\u0000\u0001\u001f\u007f\u0080é€￿😀", "\"\\\/\b\f\n\r\t", "aéあ😀b", "long text beyond the eight bytes of a word \n with an escape in the middle"])";
        const ordered_json_document d = ordered_json_document::parse(text);
        const ordered_json j = ordered_json::parse(text);
        CHECK(d.root().dump() == j.dump());
        CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
        CHECK(d.root().dump(4, ' ', true) == j.dump(4, ' ', true));
        const ordered_json_document keys = ordered_json_document::parse(R"({"é\n": {"\"": [], "": {}}})");
        CHECK(keys.root().dump(2, ' ', true) == ordered_json::parse(R"({"é\n": {"\"": [], "": {}}})").dump(2, ' ', true));
    }

    SECTION("numbers")
    {
        const std::string text = "[1.50, 1E2, -0, -0.0, 123456789012345678901234567890, 18446744073709551615, -9223372036854775808, 0.1, 1e-7, 5e-324]";
        const json_document d = json_document::parse(text);
        CHECK(d.root().dump() == json::parse(text).dump());
        CHECK(d.root().dump() == "[1.5,100.0,0,-0.0,1.2345678901234568e+29,18446744073709551615,-9223372036854775808,0.1,1e-07,5e-324]");
        CHECK(d.root().dump(-1, ' ', false, json_view::number_format::source) == "[1.50,1E2,-0,-0.0,123456789012345678901234567890,18446744073709551615,-9223372036854775808,0.1,1e-7,5e-324]");

        // random doubles, written as parse() and dump() would
        std::mt19937_64 rng(1170); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
        std::string many = "[";
        for (int i = 0; i < 5000; ++i)
        {
            const std::uint64_t bits = rng();
            double x = 0;
            std::memcpy(&x, &bits, sizeof(x));
            if (std::isfinite(x))
            {
                many += (many.size() > 1 ? "," : "") + json(x).dump();
            }
        }
        many += ']';
        CHECK(json_document::parse(many).root().dump() == json::parse(many).dump());

        using json_float = nlohmann::basic_json<std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t, float>;
        CHECK(nlohmann::basic_json_document<json_float>::parse("[0.1, 1.5e10, 3.4028235e38]").root().dump() == json_float::parse("[0.1, 1.5e10, 3.4028235e38]").dump());
    }

    SECTION("members in document order, all of them")
    {
        const json_document d = json_document::parse(R"({"b": 1, "a": 2, "b": 3})");
        CHECK(d.root().dump() == R"({"b":1,"a":2,"b":3})");
        CHECK(d.root().dump(1) == "{\n \"b\": 1,\n \"a\": 2,\n \"b\": 3\n}");
    }

    SECTION("deep nesting")
    {
        const std::string deep = std::string(100000, '[') + std::string(100000, ']');
        CHECK(json_document::parse(deep).root().dump() == deep);
    }

    SECTION("streams and discarded views")
    {
        const json_document d = json_document::parse(R"({"a": [1, 2]})");
        std::ostringstream compact;
        compact << d.root();
        CHECK(compact.str() == R"({"a":[1,2]})");
        std::ostringstream pretty;
        pretty << std::setw(2) << std::setfill('.') << d.root() << d.root()["a"];
        CHECK(pretty.str() == "{\n..\"a\": [\n....1,\n....2\n..]\n}[1,2]");
        CHECK(json_view().dump() == json(json::value_t::discarded).dump());
    }
}

TEST_CASE("json_view comparison")
{
    SECTION("equality of the values parse() produces")
    {
        generator g;
        std::vector<std::string> texts;
        for (int i = 0; i < 600; ++i)
        {
            std::string text;
            g.value(text, 0);
            texts.push_back(text);
            // the same value written differently: sorted keys, canonical numbers
            texts.push_back(json::parse(text).dump(1));
        }
        for (std::size_t i = 0; i + 2 < texts.size(); ++i)
        {
            for (std::size_t k = i; k < i + 3; ++k)
            {
                CAPTURE(texts[i]);
                CAPTURE(texts[k]);
                const json_document a = json_document::parse(texts[i]);
                const json_document b = json_document::parse(texts[k]);
                const json ja = json::parse(texts[i]);
                const json jb = json::parse(texts[k]);
                CHECK((a.root() == b.root()) == (ja == jb));
                CHECK((a.root() != b.root()) == (ja != jb));
                CHECK((a.root() == jb) == (ja == jb));
                CHECK((jb == a.root()) == (ja == jb));
                CHECK((a.root() != jb) == (ja != jb));
                CHECK((jb != a.root()) == (ja != jb));

                // ordered_json compares members in order
                const ordered_json_document oa = ordered_json_document::parse(texts[i]);
                const ordered_json_document ob = ordered_json_document::parse(texts[k]);
                const ordered_json oja = ordered_json::parse(texts[i]);
                const ordered_json ojb = ordered_json::parse(texts[k]);
                CHECK((oa.root() == ob.root()) == (oja == ojb));
                CHECK((oa.root() == ojb) == (oja == ojb));
            }
        }
    }

    SECTION("numbers, duplicate keys, member order")
    {
        const auto same = [](const char* x, const char* y)
        {
            return json_document::parse(x).root() == json_document::parse(y).root();
        };
        CHECK(same("1", "1.0"));
        CHECK(same("[1, -1, 2.5]", "[1.0, -1.0, 25e-1]"));
        CHECK(!same("1", "1.5"));
        CHECK(same("18446744073709551615", "18446744073709551615"));
        CHECK(same(R"({"a": 1, "a": 2})", R"({"a": 2})"));
        CHECK(!same(R"({"a": 1, "a": 2})", R"({"a": 1})"));
        CHECK(same(R"({"a": 1, "b": 2})", R"({"b": 2, "a": 1})"));
        CHECK(!same(R"({"a": 1})", R"({"a": 1, "b": 2})"));
        CHECK(!same("[1, 2]", "[2, 1]"));
        CHECK(!same("\"a\"", "\"b\""));
        CHECK(same("\"\\u00e9\"", "\"\xc3\xa9\""));
        CHECK(!same("null", "false"));
        CHECK(!same("[]", "{}"));
        CHECK(ordered_json_document::parse(R"({"a": 1, "b": 2, "a": 3})").root() == ordered_json_document::parse(R"({"a": 3, "b": 2})").root());
        CHECK(ordered_json_document::parse(R"({"a": 1, "b": 2})").root() != ordered_json_document::parse(R"({"b": 2, "a": 1})").root());

        // discarded values compare as basic_json's do
        const json discarded(json::value_t::discarded);
        CHECK((json_view() == json_view()) == (discarded == discarded)); // NOLINT(readability-container-size-empty): operator== is tested
        CHECK((json_view() == discarded) == (discarded == discarded));
        CHECK(!(json_view() == json_document::parse("null").root())); // NOLINT(readability-container-size-empty)
        CHECK(!(json_document::parse("null").root() == discarded));
    }

    SECTION("deep nesting")
    {
        const std::string deep = std::string(100000, '[') + std::string(100000, ']');
        const json_document a = json_document::parse(deep);
        const json_document b = json_document::parse(deep);
        CHECK(a.root() == b.root());
        CHECK(a.root() == json::parse(deep));
        const std::string other = std::string(100000, '[') + "1" + std::string(100000, ']');
        CHECK(a.root() != json_document::parse(other).root());
    }
}

TEST_CASE("json_view large objects")
{
    // objects with 128 members or more are looked up with a hash index
    for (const std::size_t members :
            {
                127u, 128u, 129u, 10000u
            })
    {
        CAPTURE(members);
        std::string text = "{";
        for (std::size_t i = 0; i < members; ++i)
        {
            text += (i != 0 ? ",\"" : "\"") + std::string(i % 23, 'k') + std::to_string(i) + (i % 7 == 0 ? "\\n" : "") + "\":" + std::to_string(i);
        }
        text += R"(,"":"empty key","k1":"a duplicate of an earlier key"})";
        const json_document d = json_document::parse(text);
        const json_view v = d.root();
        const json j = json::parse(text);
        for (std::size_t i = 0; i < members; ++i)
        {
            const std::string key = std::string(i % 23, 'k') + std::to_string(i) + (i % 7 == 0 ? "\n" : "");
            CHECK(v[key].get<std::size_t>() == i);
            CHECK(v.contains(key));
            CHECK(v.find(key).key() == key);
            CHECK(v.at(key).get<std::size_t>() == i);
            CHECK(!v.contains(key + "x"));
        }
        CHECK(v[""].get_string() == "empty key");
        CHECK(v["k1"].get<int>() == 1); // the first of duplicate keys, as for small objects
        CHECK(!v.contains("missing"));
        CHECK_THROWS_WITH_AS(v.at("missing"), "[json.exception.out_of_range.403] key 'missing' not found", json::out_of_range&);
        CHECK(v == j);
        CHECK(v.materialize() == j);
    }

    SECTION("nested, reused, and in arrays")
    {
        std::string inner = "{";
        for (int i = 0; i < 300; ++i)
        {
            inner += (i != 0 ? ",\"m" : "\"m") + std::to_string(i) + "\":" + std::to_string(i);
        }
        inner += '}';
        const std::string text = "[" + inner + ",{\"x\":" + inner + "}," + inner + "]";
        json_document d = json_document::parse(text);
        CHECK(d.root()[0]["m299"].get<int>() == 299);
        CHECK(d.root()[1]["x"]["m150"].get<int>() == 150);
        CHECK(d.root()[2]["m0"].get<int>() == 0);
        const std::size_t with_index = d.memory_usage();
        d.read(std::string("{\"small\": 1}"));
        CHECK(d.root()["small"].get<int>() == 1);
        d.read(text);
        CHECK(d.root()[2]["m7"].get<int>() == 7);
        CHECK(d.memory_usage() >= with_index / 2);
    }
}