132 lines
3.2 KiB
C++
132 lines
3.2 KiB
C++
#include <iostream>
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#include <iomanip>
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#include <sstream>
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#include <nlohmann/json.hpp>
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using json = nlohmann::json;
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// a simple event consumer that collects string representations of the passed
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// values; note inheriting from json::json_sax_t is not required, but can
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// help not to forget a required function
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class sax_event_consumer : public json::json_sax_t
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{
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public:
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std::vector<std::string> events;
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bool null() override
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{
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events.push_back("null()");
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return true;
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}
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bool boolean(bool val) override
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{
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events.push_back("boolean(val=" + std::string(val ? "true" : "false") + ")");
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return true;
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}
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bool number_integer(number_integer_t val) override
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{
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events.push_back("number_integer(val=" + std::to_string(val) + ")");
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return true;
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}
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bool number_unsigned(number_unsigned_t val) override
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{
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events.push_back("number_unsigned(val=" + std::to_string(val) + ")");
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return true;
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}
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bool number_float(number_float_t val, const string_t& s) override
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{
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events.push_back("number_float(val=" + std::to_string(val) + ", s=" + s + ")");
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return true;
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}
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bool string(string_t& val) override
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{
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events.push_back("string(val=" + val + ")");
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return true;
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}
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bool start_object(std::size_t elements) override
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{
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events.push_back("start_object(elements=" + std::to_string(elements) + ")");
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return true;
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}
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bool end_object() override
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{
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events.push_back("end_object()");
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return true;
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}
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bool start_array(std::size_t elements) override
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{
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events.push_back("start_array(elements=" + std::to_string(elements) + ")");
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return true;
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}
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bool end_array() override
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{
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events.push_back("end_array()");
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return true;
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}
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bool key(string_t& val) override
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{
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events.push_back("key(val=" + val + ")");
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return true;
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}
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bool binary(json::binary_t& val) override
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{
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events.push_back("binary(val=[...])");
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return true;
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}
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bool parse_error(std::size_t position, const std::string& last_token, const json::exception& ex) override
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{
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events.push_back("parse_error(position=" + std::to_string(position) + ", last_token=" + last_token + ",\n ex=" + std::string(ex.what()) + ")");
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return false;
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}
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};
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int main()
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{
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// a JSON text
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auto text = R"(
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{
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"Image": {
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"Width": 800,
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"Height": 600,
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"Title": "View from 15th Floor",
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"Thumbnail": {
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"Url": "http://www.example.com/image/481989943",
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"Height": 125,
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"Width": 100
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},
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"Animated" : false,
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"IDs": [116, 943, 234, -38793],
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"DeletionDate": null,
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"Distance": 12.723374634
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}
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}]
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)";
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// create a SAX event consumer object
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sax_event_consumer sec;
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// parse JSON
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bool result = json::sax_parse(text, &sec);
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// output the recorded events
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for (auto& event : sec.events)
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{
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std::cout << event << "\n";
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}
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// output the result of sax_parse
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std::cout << "\nresult: " << std::boolalpha << result << std::endl;
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}
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