commit
fe5e2167a5
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test |
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test: json11.cpp json11.hpp test.cpp |
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clang++ -O -std=c++11 -stdlib=libc++ json11.cpp test.cpp -o test -fno-rtti -fno-exceptions
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json11 |
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------ |
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|
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json11 is a tiny JSON library for C++11, providing JSON parsing and serialization. |
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The core object provided by the library is json11::Json. A Json object represents any JSON |
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value: null, bool, number (int or double), string (std::string), array (std::vector), or |
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object (std::map). |
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|
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Json objects act like values. They can be assigned, copied, moved, compared for equality or |
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order, and so on. There are also helper methods Json::dump, to serialize a Json to a string, and |
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Json::parse (static) to parse a std::string as a Json object. |
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|
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It's easy to make a JSON object with C++11's new initializer syntax: |
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Json my_json = Json::object { |
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{ "key1", "value1" }, |
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{ "key2", false }, |
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{ "key3", Json::array { 1, 2, 3 } }, |
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}; |
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std::string json_str = my_json.dump(); |
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|
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There are also implicit constructors that allow standard and user-defined types to be |
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automatically converted to JSON. For example: |
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class Point { |
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public: |
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int x; |
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int y; |
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Point (int x, int y) : x(x), y(y) {} |
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Json to_json() const { return Json::array { x, y }; } |
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}; |
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std::vector<Point> points = { { 1, 2 }, { 10, 20 }, { 100, 200 } }; |
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std::string points_json = Json(points).dump(); |
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JSON values can have their values queried and inspected: |
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Json json = Json::array { Json::object { { "k", "v" } } }; |
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std::string str = json[0]["k"].string_value(); |
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|
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More documentation is still to come. For now, see json11.hpp. |
@ -0,0 +1,674 @@ |
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/* Copyright (c) 2013 Dropbox, Inc.
|
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this software and associated documentation files (the "Software"), to deal |
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* in the Software without restriction, including without limitation the rights |
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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* copies of the Software, and to permit persons to whom the Software is |
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* furnished to do so, subject to the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be included in |
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* all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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* THE SOFTWARE. |
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*/ |
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|
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#include "json11.hpp" |
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#include <cassert> |
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#include <cstdlib> |
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#include <cstdio> |
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#include <limits> |
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namespace json11 { |
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using std::string; |
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using std::vector; |
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using std::map; |
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using std::make_shared; |
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using std::initializer_list; |
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using std::move; |
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/* * * * * * * * * * * * * * * * * * * *
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* Serialization |
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*/ |
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static void dump(std::nullptr_t, string &out) { |
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out += "null"; |
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} |
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|
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static void dump(double value, string &out) { |
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char buf[32]; |
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snprintf(buf, sizeof buf, "%.17g", value); |
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out += buf; |
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} |
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|
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static void dump(int value, string &out) { |
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char buf[32]; |
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snprintf(buf, sizeof buf, "%d", value); |
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out += buf; |
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} |
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|
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static void dump(bool value, string &out) { |
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out += value ? "true" : "false"; |
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} |
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static void dump(const string &value, string &out) { |
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out += '"'; |
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for (size_t i = 0; i < value.length(); i++) { |
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const char ch = value[i]; |
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if (ch == '\\') { |
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out += "\\\\"; |
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} else if (ch == '"') { |
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out += "\\\""; |
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} else if (ch == '\b') { |
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out += "\\b"; |
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} else if (ch == '\f') { |
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out += "\\f"; |
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} else if (ch == '\n') { |
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out += "\\n"; |
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} else if (ch == '\r') { |
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out += "\\r"; |
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} else if (ch == '\t') { |
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out += "\\t"; |
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} else if ((uint8_t)ch <= 0x1f) { |
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char buf[8]; |
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snprintf(buf, sizeof buf, "\\u%04x", ch); |
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out += buf; |
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} else if ((uint8_t)ch == 0xe2 && (uint8_t)value[i+1] == 0x80 |
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&& (uint8_t)value[i+2] == 0xa8) { |
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out += "\\u2028"; |
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i += 2; |
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} else if ((uint8_t)ch == 0xe2 && (uint8_t)value[i+1] == 0x80 |
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&& (uint8_t)value[i+2] == 0xa9) { |
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out += "\\u2029"; |
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i += 2; |
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} else { |
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out += ch; |
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} |
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} |
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out += '"'; |
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} |
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|
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static void dump(const Json::array &values, string &out) { |
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bool first = true; |
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out += "["; |
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for (auto &value : values) { |
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if (!first) |
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out += ", "; |
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value.dump(out); |
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first = false; |
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} |
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out += "]"; |
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} |
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|
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static void dump(const Json::object &values, string &out) { |
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bool first = true; |
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out += "{"; |
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for (const std::pair<string, Json> &kv : values) { |
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if (!first) |
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out += ", "; |
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dump(kv.first, out); |
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out += ": "; |
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kv.second.dump(out); |
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first = false; |
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} |
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out += "}"; |
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} |
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void Json::dump(string &out) const { |
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m_ptr->dump(out); |
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} |
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/* * * * * * * * * * * * * * * * * * * *
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* Value wrappers |
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*/ |
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template <Json::Type tag, typename T> |
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class Value : public JsonValue { |
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protected: |
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|
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// Constructors
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Value(const T &value) : m_value(value) {} |
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Value(T &&value) : m_value(move(value)) {} |
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|
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// Get type tag
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Json::Type type() const { |
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return tag; |
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} |
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|
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// Comparisons
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bool equals(const JsonValue * other) const { |
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return m_value == reinterpret_cast<const Value<tag, T> *>(other)->m_value; |
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} |
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bool less(const JsonValue * other) const { |
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return m_value < reinterpret_cast<const Value<tag, T> *>(other)->m_value; |
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} |
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const T m_value; |
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void dump(string &out) const { json11::dump(m_value, out); } |
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}; |
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class JsonDouble final : public Value<Json::NUMBER, double> { |
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double number_value() const { return m_value; } |
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int int_value() const { return m_value; } |
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bool equals(const JsonValue * other) const { return m_value == other->number_value(); } |
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bool less(const JsonValue * other) const { return m_value < other->number_value(); } |
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public: |
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JsonDouble(double value) : Value(value) {} |
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}; |
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class JsonInt final : public Value<Json::NUMBER, int> { |
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double number_value() const { return m_value; } |
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int int_value() const { return m_value; } |
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bool equals(const JsonValue * other) const { return m_value == other->number_value(); } |
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bool less(const JsonValue * other) const { return m_value < other->number_value(); } |
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public: |
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JsonInt(double value) : Value(value) {} |
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}; |
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class JsonBoolean final : public Value<Json::BOOL, bool> { |
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bool bool_value() const { return m_value; } |
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public: |
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JsonBoolean(bool value) : Value(value) {} |
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}; |
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class JsonString final : public Value<Json::STRING, string> { |
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const string &string_value() const { return m_value; } |
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public: |
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JsonString(const string &value) : Value(value) {} |
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JsonString(string &&value) : Value(move(value)) {} |
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}; |
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class JsonArray final : public Value<Json::ARRAY, Json::array> { |
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const Json::array &array_items() const { return m_value; } |
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const Json & operator[](size_t i) const; |
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public: |
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JsonArray(const Json::array &value) : Value(value) {} |
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JsonArray(Json::array &&value) : Value(move(value)) {} |
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}; |
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class JsonObject final : public Value<Json::OBJECT, Json::object> { |
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const Json::object &object_items() const { return m_value; } |
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const Json & operator[](const string &key) const; |
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public: |
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JsonObject(const Json::object &value) : Value(value) {} |
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JsonObject(Json::object &&value) : Value(move(value)) {} |
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}; |
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class JsonNull final : public Value<Json::NUL, std::nullptr_t> { |
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public: |
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JsonNull() : Value(nullptr) {} |
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}; |
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|
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/* * * * * * * * * * * * * * * * * * * *
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* Constructors |
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*/ |
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static const std::shared_ptr<JsonValue> obj_null(make_shared<JsonNull>()); |
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static const std::shared_ptr<JsonValue> obj_true(make_shared<JsonBoolean>(true)); |
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static const std::shared_ptr<JsonValue> obj_false(make_shared<JsonBoolean>(false)); |
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Json::Json() noexcept : m_ptr(obj_null) {} |
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Json::Json(std::nullptr_t) noexcept : m_ptr(obj_null) {} |
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Json::Json(double value) : m_ptr(make_shared<JsonDouble>(value)) {} |
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Json::Json(int value) : m_ptr(make_shared<JsonInt>(value)) {} |
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Json::Json(bool value) : m_ptr(value ? obj_true : obj_false) {} |
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Json::Json(const string &value) : m_ptr(make_shared<JsonString>(value)) {} |
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Json::Json(string &&value) : m_ptr(make_shared<JsonString>(move(value))) {} |
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Json::Json(const char * value) : m_ptr(make_shared<JsonString>(value)) {} |
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Json::Json(const Json::array &values) : m_ptr(make_shared<JsonArray>(values)) {} |
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Json::Json(Json::array &&values) : m_ptr(make_shared<JsonArray>(move(values))) {} |
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Json::Json(const Json::object &values) : m_ptr(make_shared<JsonObject>(values)) {} |
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Json::Json(Json::object &&values) : m_ptr(make_shared<JsonObject>(move(values))) {} |
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/* * * * * * * * * * * * * * * * * * * *
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* Accessors |
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*/ |
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static const string empty_string; |
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static const vector<Json> empty_vector; |
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static const map<string, Json> empty_map; |
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static const Json json_null; |
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Json::Type Json::type() const { return m_ptr->type(); } |
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double Json::number_value() const { return m_ptr->number_value(); } |
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int Json::int_value() const { return m_ptr->int_value(); } |
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bool Json::bool_value() const { return m_ptr->bool_value(); } |
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const string & Json::string_value() const { return m_ptr->string_value(); } |
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const vector<Json> & Json::array_items() const { return m_ptr->array_items(); } |
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const map<string, Json> & Json::object_items() const { return m_ptr->object_items(); } |
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const Json & Json::operator[] (size_t i) const { return (*m_ptr)[i]; } |
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const Json & Json::operator[] (const string &key) const { return (*m_ptr)[key]; } |
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double JsonValue::number_value() const { return 0; } |
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int JsonValue::int_value() const { return 0; } |
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bool JsonValue::bool_value() const { return false; } |
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const string & JsonValue::string_value() const { return empty_string; } |
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const vector<Json> & JsonValue::array_items() const { return empty_vector; } |
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const map<string, Json> & JsonValue::object_items() const { return empty_map; } |
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const Json & JsonValue::operator[] (size_t) const { return json_null; } |
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const Json & JsonValue::operator[] (const string &) const { return json_null; } |
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const Json & JsonObject::operator[] (const string &key) const { |
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auto iter = m_value.find(key); |
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return (iter == m_value.end()) ? json_null : iter->second; |
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} |
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const Json & JsonArray::operator[] (size_t i) const { |
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if (i >= m_value.size()) return json_null; |
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else return m_value[i]; |
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} |
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|
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/* * * * * * * * * * * * * * * * * * * *
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* Comparison |
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*/ |
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bool Json::operator== (const Json &other) const { |
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if (m_ptr->type() != other.m_ptr->type()) |
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return false; |
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return m_ptr->equals(other.m_ptr.get()); |
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} |
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bool Json::operator< (const Json &other) const { |
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if (m_ptr->type() != other.m_ptr->type()) |
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return m_ptr->type() < other.m_ptr->type(); |
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return m_ptr->less(other.m_ptr.get()); |
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} |
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|
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/* * * * * * * * * * * * * * * * * * * *
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* Parsing |
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*/ |
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|
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/* esc(c)
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* |
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* Format char c suitable for printing in an error message. |
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*/ |
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static inline string esc(char c) { |
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char buf[12]; |
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if ((uint8_t)c >= 0x20 && (uint8_t)c <= 0x7f) { |
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snprintf(buf, sizeof buf, "'%c' (%d)", c, c); |
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} else { |
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snprintf(buf, sizeof buf, "(%d)", c); |
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} |
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return string(buf); |
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} |
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static inline bool in_range (int x, int lower, int upper) { |
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return (x >= lower && x <= upper); |
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} |
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|
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/* JsonParser
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* |
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* Object that tracks all state of an in-progress parse. |
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*/ |
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struct JsonParser { |
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|
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/* State
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*/ |
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const string &str; |
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size_t i; |
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string &err; |
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bool failed; |
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|
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/* fail(msg, err_ret = Json())
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* |
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* Mark this parse as failed. |
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*/ |
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Json fail(string &&msg) { |
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return fail(move(msg), Json()); |
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} |
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template <typename T> |
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T fail(string &&msg, const T err_ret) { |
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if (!failed) |
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err = std::move(msg); |
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failed = true; |
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return err_ret; |
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} |
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|
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/* consume_whitespace()
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* |
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* Advance until the current character is non-whitespace. |
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*/ |
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void consume_whitespace() { |
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while (str[i] == ' ' || str[i] == '\r' || str[i] == '\n' || str[i] == '\t') |
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i++; |
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} |
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|
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/* get_next_token()
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* |
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* Return the next non-whitespace character. If the end of the input is reached, |
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* flag an error and return 0. |
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*/ |
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char get_next_token() { |
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consume_whitespace(); |
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if (i == str.size()) |
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return fail("unexpected end of input", 0); |
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|
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return str[i++]; |
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} |
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|
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/* encode_utf8(pt, out)
|
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* |
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* Encode pt as UTF-8 and add it to out. |
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*/ |
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void encode_utf8(long pt, string & out) { |
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if (pt < 0) |
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return; |
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|
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if (pt < 0x80) { |
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out += pt; |
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} else if (pt < 0x800) { |
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out += (pt >> 6) | 0xC0; |
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out += (pt & 0x3F) | 0x80; |
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} else if (pt < 0x10000) { |
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out += (pt >> 12) | 0xE0; |
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out += ((pt >> 6) & 0x3F) | 0x80; |
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out += (pt & 0x3F) | 0x80; |
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} else { |
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out += (pt >> 18) | 0xF0; |
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out += ((pt >> 12) & 0x3F) | 0x80; |
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out += ((pt >> 6) & 0x3F) | 0x80; |
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out += (pt & 0x3F) | 0x80; |
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} |
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} |
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|
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/* parse_string()
|
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* |
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* Parse a string, starting at the current position. |
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*/ |
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string parse_string() { |
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string out; |
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long last_escaped_codepoint = -1; |
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while (true) { |
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if (i == str.size()) |
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return fail("unexpected end of input in string", ""); |
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|
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char ch = str[i++]; |
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|
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if (ch == '"') { |
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encode_utf8(last_escaped_codepoint, out); |
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return out; |
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} |
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|
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if (in_range(ch, 0, 0x1f)) |
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return fail("unescaped " + esc(ch) + " in string", ""); |
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|
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// The usual case: non-escaped characters
|
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if (ch != '\\') { |
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encode_utf8(last_escaped_codepoint, out); |
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last_escaped_codepoint = -1; |
||||
out += ch; |
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continue; |
||||
} |
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|
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// Handle escapes
|
||||
if (i == str.size()) |
||||
return fail("unexpected end of input in string", ""); |
||||
|
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ch = str[i++]; |
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|
||||
if (ch == 'u') { |
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// Extract 4-byte escape sequence
|
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string esc = str.substr(i, 4); |
||||
for (int j = 0; j < 4; j++) { |
||||
if (!in_range(esc[j], 'a', 'f') && !in_range(esc[j], 'A', 'F') |
||||
&& !in_range(esc[j], '0', '9')) |
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return fail("bad \\u escape: " + esc, ""); |
||||
} |
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|
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long codepoint = strtol(esc.data(), nullptr, 16); |
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|
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// JSON specifies that characters outside the BMP shall be encoded as a pair
|
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// of 4-hex-digit \u escapes encoding their surrogate pair components. Check
|
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// whether we're in the middle of such a beast: the previous codepoint was an
|
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// escaped lead (high) surrogate, and this is a trail (low) surrogate.
|
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if (in_range(last_escaped_codepoint, 0xD800, 0xDBFF) |
||||
&& in_range(codepoint, 0xDC00, 0xDFFF)) { |
||||
// Reassemble the two surrogate pairs into one astral-plane character, per
|
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// the UTF-16 algorithm.
|
||||
encode_utf8((((last_escaped_codepoint - 0xD800) << 10) |
||||
| (codepoint - 0xDC00)) + 0x10000, out); |
||||
last_escaped_codepoint = -1; |
||||
} else { |
||||
encode_utf8(last_escaped_codepoint, out); |
||||
last_escaped_codepoint = codepoint; |
||||
} |
||||
|
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i += 4; |
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continue; |
||||
} |
||||
|
||||
encode_utf8(last_escaped_codepoint, out); |
||||
last_escaped_codepoint = -1; |
||||
|
||||
if (ch == 'b') { |
||||
out += '\b'; |
||||
} else if (ch == 'f') { |
||||
out += '\f'; |
||||
} else if (ch == 'n') { |
||||
out += '\n'; |
||||
} else if (ch == 'r') { |
||||
out += '\r'; |
||||
} else if (ch == 't') { |
||||
out += '\t'; |
||||
} else if (ch == '"' || ch == '\\' || ch == '/') { |
||||
out += ch; |
||||
} else { |
||||
return fail("invalid escape character " + esc(ch), ""); |
||||
} |
||||
} |
||||
} |
||||
|
||||
/* parse_number()
|
||||
* |
||||
* Parse a double. |
||||
*/ |
||||
Json parse_number() { |
||||
size_t start_pos = i; |
||||
|
||||
if (str[i] == '-') |
||||
i++; |
||||
|
||||
// Integer part
|
||||
if (str[i] == '0') { |
||||
i++; |
||||
if (in_range(str[i], '0', '9')) |
||||
return fail("leading 0s not permitted in numbers"); |
||||
} else if (in_range(str[i], '1', '9')) { |
||||
i++; |
||||
while (in_range(str[i], '0', '9')) |
||||
i++; |
||||
} else { |
||||
return fail("invalid " + esc(str[i]) + " in number"); |
||||
} |
||||
|
||||
if (str[i] != '.' && str[i] != 'e' && str[i] != 'E' |
||||
&& (i - start_pos) <= (size_t)std::numeric_limits<int>::digits10) { |
||||
return std::atoi(str.c_str() + start_pos); |
||||
} |
||||
|
||||
// Decimal part
|
||||
if (str[i] == '.') { |
||||
i++; |
||||
if (!in_range(str[i], '0', '9')) |
||||
return fail("at least one digit required in fractional part"); |
||||
|
||||
while (in_range(str[i], '0', '9')) |
||||
i++; |
||||
} |
||||
|
||||
// Exponent part
|
||||
if (str[i] == 'e' || str[i] == 'E') { |
||||
i++; |
||||
|
||||
if (str[i] == '+' || str[i] == '-') |
||||
i++; |
||||
|
||||
if (!in_range(str[i], '0', '9')) |
||||
return fail("at least one digit required in exponent"); |
||||
|
||||
while (in_range(str[i], '0', '9')) |
||||
i++; |
||||
} |
||||
|
||||
return std::atof(str.c_str() + start_pos); |
||||
} |
||||
|
||||
/* expect(str, res)
|
||||
* |
||||
* Expect that 'str' starts at the character that was just read. If it does, advance |
||||
* the input and return res. If not, flag an error. |
||||
*/ |
||||
Json expect(const string &expected, Json res) { |
||||
assert(i != 0); |
||||
i--; |
||||
const string found = str.substr(i, expected.length()); |
||||
if (expected == found) { |
||||
i += expected.length(); |
||||
return res; |
||||
} else { |
||||
return fail("parse error: expected " + expected + ", got " + found); |
||||
} |
||||
} |
||||
|
||||
/* parse_json()
|
||||
* |
||||
* Parse a JSON object. |
||||
*/ |
||||
Json parse_json() { |
||||
char ch = get_next_token(); |
||||
if (failed) |
||||
return Json(); |
||||
|
||||
if (ch == '-' || (ch >= '0' && ch <= '9')) { |
||||
i--; |
||||
return parse_number(); |
||||
} |
||||
|
||||
if (ch == 't') |
||||
return expect("true", true); |
||||
|
||||
if (ch == 'f') |
||||
return expect("false", false); |
||||
|
||||
if (ch == 'n') |
||||
return expect("null", Json()); |
||||
|
||||
if (ch == '"') |
||||
return parse_string(); |
||||
|
||||
if (ch == '{') { |
||||
map<string, Json> data; |
||||
ch = get_next_token(); |
||||
if (ch == '}') |
||||
return data; |
||||
|
||||
while (1) { |
||||
if (ch != '"') |
||||
return fail("expected '\"' in object, got " + esc(ch)); |
||||
|
||||
string key = parse_string(); |
||||
if (failed) |
||||
return Json(); |
||||
|
||||
ch = get_next_token(); |
||||
if (ch != ':') |
||||
return fail("expected ':' in object, got " + esc(ch)); |
||||
|
||||
data[std::move(key)] = parse_json(); |
||||
if (failed) |
||||
return Json(); |
||||
|
||||
ch = get_next_token(); |
||||
if (ch == '}') |
||||
break; |
||||
if (ch != ',') |
||||
return fail("expected ',' in object, got " + esc(ch)); |
||||
|
||||
ch = get_next_token(); |
||||
} |
||||
return data; |
||||
} |
||||
|
||||
if (ch == '[') { |
||||
vector<Json> data; |
||||
ch = get_next_token(); |
||||
if (ch == ']') |
||||
return data; |
||||
|
||||
while (1) { |
||||
i--; |
||||
data.push_back(parse_json()); |
||||
if (failed) |
||||
return Json(); |
||||
|
||||
ch = get_next_token(); |
||||
if (ch == ']') |
||||
break; |
||||
if (ch != ',') |
||||
return fail("expected ',' in list, got " + esc(ch)); |
||||
|
||||
ch = get_next_token(); |
||||
(void)ch; |
||||
} |
||||
return data; |
||||
} |
||||
|
||||
return fail("expected value, got " + esc(ch)); |
||||
} |
||||
}; |
||||
|
||||
Json Json::parse(const string &in, string &err) { |
||||
JsonParser parser { in, 0, err, false }; |
||||
Json result = parser.parse_json(); |
||||
|
||||
// Check for any trailing garbage
|
||||
parser.consume_whitespace(); |
||||
if (parser.i != in.size()) |
||||
return parser.fail("unexpected trailing " + esc(in[parser.i])); |
||||
|
||||
return result; |
||||
} |
||||
|
||||
// Documented in json11.hpp
|
||||
vector<Json> Json::parse_multi(const string &in, string &err) { |
||||
JsonParser parser { in, 0, err, false }; |
||||
|
||||
vector<Json> json_vec; |
||||
while (parser.i != in.size() && !parser.failed) { |
||||
json_vec.push_back(parser.parse_json()); |
||||
// Check for another object
|
||||
parser.consume_whitespace(); |
||||
} |
||||
return json_vec; |
||||
} |
||||
|
||||
/* * * * * * * * * * * * * * * * * * * *
|
||||
* Shape-checking |
||||
*/ |
||||
|
||||
bool Json::has_shape(const shape & types, string & err) const { |
||||
if (!is_object()) { |
||||
err = "expected JSON object, got " + dump(); |
||||
return false; |
||||
} |
||||
|
||||
for (auto & item : types) { |
||||
if ((*this)[item.first].type() != item.second) { |
||||
err = "bad type for " + item.first + " in " + dump(); |
||||
return false; |
||||
} |
||||
} |
||||
|
||||
return true; |
||||
} |
||||
|
||||
} // namespace json11
|
@ -0,0 +1,187 @@ |
||||
/* json11
|
||||
* |
||||
* json11 is a tiny JSON library for C++11, providing JSON parsing and serialization. |
||||
* |
||||
* The core object provided by the library is json11::Json. A Json object represents any JSON |
||||
* value: null, bool, number (int or double), string (std::string), array (std::vector), or |
||||
* object (std::map). |
||||
* |
||||
* Json objects act like values: they can be assigned, copied, moved, compared for equality or |
||||
* order, etc. There are also helper methods Json::dump, to serialize a Json to a string, and |
||||
* Json::parse (static) to parse a std::string as a Json object. |
||||
* |
||||
* Internally, the various types of Json object are represented by the JsonValue class
|
||||
* hierarchy. |
||||
*/ |
||||
|
||||
/* Copyright (c) 2013 Dropbox, Inc.
|
||||
* |
||||
* 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. |
||||
*/ |
||||
|
||||
#pragma once |
||||
|
||||
#include <string> |
||||
#include <vector> |
||||
#include <map> |
||||
#include <memory> |
||||
#include <initializer_list> |
||||
|
||||
namespace json11 { |
||||
|
||||
class JsonValue; |
||||
|
||||
class Json final { |
||||
public: |
||||
// Types
|
||||
enum Type { |
||||
NUL, NUMBER, BOOL, STRING, ARRAY, OBJECT |
||||
}; |
||||
|
||||
// Array and object typedefs
|
||||
typedef std::vector<Json> array; |
||||
typedef std::map<std::string, Json> object; |
||||
|
||||
// Constructors for the various types of JSON value.
|
||||
Json() noexcept; // NUL
|
||||
Json(std::nullptr_t) noexcept; // NUL
|
||||
Json(double value); // NUMBER
|
||||
Json(int value); // NUMBER
|
||||
Json(bool value); // BOOL
|
||||
Json(const std::string &value); // STRING
|
||||
Json(std::string &&value); // STRING
|
||||
Json(const char * value); // STRING
|
||||
Json(const array &values); // ARRAY
|
||||
Json(array &&values); // ARRAY
|
||||
Json(const object &values); // OBJECT
|
||||
Json(object &&values); // OBJECT
|
||||
|
||||
// Implicit constructor: anything with a to_json() function.
|
||||
template <class T, class = decltype(&T::to_json)> |
||||
Json(const T & t) : Json(t.to_json()) {} |
||||
|
||||
// Implicit constructor: map-like objects (std::map, std::unordered_map, etc)
|
||||
template <class M, typename std::enable_if< |
||||
std::is_constructible<std::string, decltype(std::declval<M>().begin()->first)>::value |
||||
&& std::is_constructible<Json, decltype(std::declval<M>().begin()->second)>::value, |
||||
int>::type = 0> |
||||
Json(const M & m) : Json(object(m.begin(), m.end())) {} |
||||
|
||||
// Implicit constructor: vector-like objects (std::list, std::vector, std::set, etc)
|
||||
template <class V, typename std::enable_if< |
||||
std::is_constructible<Json, decltype(*std::declval<V>().begin())>::value, |
||||
int>::type = 0> |
||||
Json(const V & v) : Json(array(v.begin(), v.end())) {} |
||||
|
||||
// This prevents Json(some_pointer) from accidentally producing a bool. Use
|
||||
// Json(bool(some_pointer)) if that behavior is desired.
|
||||
Json(void *) = delete; |
||||
|
||||
// Accessors
|
||||
Type type() const; |
||||
|
||||
bool is_null() const { return type() == NUL; } |
||||
bool is_number() const { return type() == NUMBER; } |
||||
bool is_bool() const { return type() == BOOL; } |
||||
bool is_string() const { return type() == STRING; } |
||||
bool is_array() const { return type() == ARRAY; } |
||||
bool is_object() const { return type() == OBJECT; } |
||||
|
||||
// Return the enclosed value if this is a number, 0 otherwise. Note that json11 does not
|
||||
// distinguish between integer and non-integer numbers - number_value() and int_value()
|
||||
// can both be applied to a NUMBER-typed object.
|
||||
double number_value() const; |
||||
int int_value() const; |
||||
|
||||
// Return the enclosed value if this is a boolean, false otherwise.
|
||||
bool bool_value() const; |
||||
// Return the enclosed string if this is a string, "" otherwise.
|
||||
const std::string &string_value() const; |
||||
// Return the enclosed std::vector if this is an array, or an empty vector otherwise.
|
||||
const array &array_items() const; |
||||
// Return the enclosed std::map if this is an object, or an empty map otherwise.
|
||||
const object &object_items() const; |
||||
|
||||
// Return a reference to arr[i] if this is an object, Json() otherwise.
|
||||
const Json & operator[](size_t i) const; |
||||
// Return a reference to obj[key] if this is an object, Json() otherwise.
|
||||
const Json & operator[](const std::string &key) const; |
||||
|
||||
// Serialize.
|
||||
void dump(std::string &out) const; |
||||
std::string dump() const { |
||||
std::string out; |
||||
dump(out); |
||||
return out; |
||||
} |
||||
|
||||
// Parse. If parse fails, return Json() and assign an error message to err.
|
||||
static Json parse(const std::string & in, std::string & err); |
||||
static Json parse(const char * in, std::string & err) { |
||||
if (in) { |
||||
return parse(std::string(in), err); |
||||
} else { |
||||
err = "null input"; |
||||
return nullptr; |
||||
} |
||||
} |
||||
// Parse multiple objects, concatenated or separated by whitespace
|
||||
static std::vector<Json> parse_multi(const std::string & in, std::string & err); |
||||
|
||||
bool operator== (const Json &rhs) const; |
||||
bool operator< (const Json &rhs) const; |
||||
bool operator!= (const Json &rhs) { return !(*this == rhs); } |
||||
bool operator<= (const Json &rhs) { return !(rhs < *this); } |
||||
bool operator> (const Json &rhs) { return (rhs < *this); } |
||||
bool operator>= (const Json &rhs) { return !(*this < rhs); } |
||||
|
||||
/* has_shape(types, err)
|
||||
* |
||||
* Return true if this is a JSON object and, for each item in types, has a field of |
||||
* the given type. If not, return false and set err to a descriptive message. |
||||
*/ |
||||
typedef std::initializer_list<std::pair<std::string, Type>> shape; |
||||
bool has_shape(const shape & types, std::string & err) const; |
||||
|
||||
private: |
||||
std::shared_ptr<JsonValue> m_ptr; |
||||
}; |
||||
|
||||
// Internal class hierarchy - JsonValue objects are not exposed to users of this API.
|
||||
class JsonValue { |
||||
protected: |
||||
friend class Json; |
||||
friend class JsonInt; |
||||
friend class JsonDouble; |
||||
virtual Json::Type type() const = 0; |
||||
virtual bool equals(const JsonValue * other) const = 0; |
||||
virtual bool less(const JsonValue * other) const = 0; |
||||
virtual void dump(std::string &out) const = 0; |
||||
virtual double number_value() const; |
||||
virtual int int_value() const; |
||||
virtual bool bool_value() const; |
||||
virtual const std::string &string_value() const; |
||||
virtual const Json::array &array_items() const; |
||||
virtual const Json &operator[](size_t i) const; |
||||
virtual const Json::object &object_items() const; |
||||
virtual const Json &operator[](const std::string &key) const; |
||||
virtual ~JsonValue() {} |
||||
}; |
||||
|
||||
} // namespace json11
|
@ -0,0 +1,100 @@ |
||||
#include <string> |
||||
#include <cstdio> |
||||
#include <iostream> |
||||
#include <sstream> |
||||
#include "json11.hpp" |
||||
#include <cassert> |
||||
|
||||
using namespace json11; |
||||
using std::string; |
||||
|
||||
// Check that Json has the properties we want.
|
||||
#include <type_traits> |
||||
#define CHECK_TRAIT(x) static_assert(std::x::value, #x) |
||||
CHECK_TRAIT(is_nothrow_constructible<Json>); |
||||
CHECK_TRAIT(is_nothrow_default_constructible<Json>); |
||||
CHECK_TRAIT(is_copy_constructible<Json>); |
||||
CHECK_TRAIT(is_nothrow_move_constructible<Json>); |
||||
CHECK_TRAIT(is_copy_assignable<Json>); |
||||
CHECK_TRAIT(is_nothrow_move_assignable<Json>); |
||||
CHECK_TRAIT(is_nothrow_destructible<Json>); |
||||
|
||||
void parse_from_stdin() { |
||||
string buf; |
||||
while (!std::cin.eof()) buf += std::cin.get(); |
||||
|
||||
string err; |
||||
auto json = Json::parse(buf, err); |
||||
if (!err.empty()) { |
||||
printf("Failed: %s\n", err.c_str()); |
||||
} else { |
||||
printf("Result: %s\n", json.dump().c_str()); |
||||
} |
||||
} |
||||
|
||||
int main(int argc, char **argv) { |
||||
if (argc == 2 && argv[1] == string("--stdin")) { |
||||
parse_from_stdin(); |
||||
return 0; |
||||
} |
||||
|
||||
const string simple_test = |
||||
R"({"k1":"v1", "k2":42, "k3":["a",123,true,false,null]})"; |
||||
|
||||
string err; |
||||
auto json = Json::parse(simple_test, err); |
||||
|
||||
std::cout << "k1: " << json["k1"].string_value() << "\n"; |
||||
std::cout << "k3: " << json["k3"].dump() << "\n"; |
||||
|
||||
for (auto &k : json["k3"].array_items()) { |
||||
std::cout << " - " << k.dump() << "\n"; |
||||
} |
||||
|
||||
// Json literals
|
||||
Json obj = Json::object({ |
||||
{ "k1", "v1" }, |
||||
{ "k2", 42.0 }, |
||||
{ "k3", Json::array({ "a", 123.0, true, false, nullptr }) }, |
||||
}); |
||||
|
||||
std::cout << "obj: " << obj.dump() << "\n"; |
||||
|
||||
assert(Json("a").number_value() == 0); |
||||
assert(Json("a").string_value() == "a"); |
||||
assert(Json().number_value() == 0); |
||||
|
||||
assert(obj == json); |
||||
assert(Json(42) == Json(42.0)); |
||||
assert(Json(42) != Json(42.1)); |
||||
|
||||
const string unicode_escape_test = |
||||
R"([ "blah\ud83d\udca9blah\ud83dblah\udca9blah\u0000blah\u1234" ])"; |
||||
|
||||
const char utf8[] = "blah" "\xf0\x9f\x92\xa9" "blah" "\xed\xa0\xbd" "blah" |
||||
"\xed\xb2\xa9" "blah" "\0" "blah" "\xe1\x88\xb4"; |
||||
|
||||
Json uni = Json::parse(unicode_escape_test, err); |
||||
assert(uni[0].string_value().size() == (sizeof utf8) - 1); |
||||
assert(memcmp(uni[0].string_value().data(), utf8, sizeof utf8) == 0); |
||||
|
||||
Json my_json = Json::object { |
||||
{ "key1", "value1" }, |
||||
{ "key2", false }, |
||||
{ "key3", Json::array { 1, 2, 3 } }, |
||||
}; |
||||
std::string json_str = my_json.dump(); |
||||
printf("%s\n", json_str.c_str()); |
||||
|
||||
class Point { |
||||
public: |
||||
int x; |
||||
int y; |
||||
Point (int x, int y) : x(x), y(y) {} |
||||
Json to_json() const { return Json::array { x, y }; } |
||||
}; |
||||
|
||||
std::vector<Point> points = { { 1, 2 }, { 10, 20 }, { 100, 200 } }; |
||||
std::string points_json = Json(points).dump(); |
||||
printf("%s\n", points_json.c_str()); |
||||
} |
Loading…
Reference in new issue