commit fe5e2167a51ad0f9dba0261843d058ab2e12e369 Author: Jacob Potter Date: Tue Sep 3 14:45:11 2013 -0700 Initial commit diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..9daeafb --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +test diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..f251c1f --- /dev/null +++ b/Makefile @@ -0,0 +1,2 @@ +test: json11.cpp json11.hpp test.cpp + clang++ -O -std=c++11 -stdlib=libc++ json11.cpp test.cpp -o test -fno-rtti -fno-exceptions diff --git a/README.md b/README.md new file mode 100644 index 0000000..21f4e8b --- /dev/null +++ b/README.md @@ -0,0 +1,42 @@ +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, and so on. 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. + +It's easy to make a JSON object with C++11's new initializer syntax: + + Json my_json = Json::object { + { "key1", "value1" }, + { "key2", false }, + { "key3", Json::array { 1, 2, 3 } }, + }; + std::string json_str = my_json.dump(); + +There are also implicit constructors that allow standard and user-defined types to be +automatically converted to JSON. For example: + + 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 points = { { 1, 2 }, { 10, 20 }, { 100, 200 } }; + std::string points_json = Json(points).dump(); + +JSON values can have their values queried and inspected: + + Json json = Json::array { Json::object { { "k", "v" } } }; + std::string str = json[0]["k"].string_value(); + +More documentation is still to come. For now, see json11.hpp. diff --git a/json11.cpp b/json11.cpp new file mode 100644 index 0000000..dc88207 --- /dev/null +++ b/json11.cpp @@ -0,0 +1,674 @@ +/* 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. + */ + +#include "json11.hpp" +#include +#include +#include +#include + +namespace json11 { + +using std::string; +using std::vector; +using std::map; +using std::make_shared; +using std::initializer_list; +using std::move; + +/* * * * * * * * * * * * * * * * * * * * + * Serialization + */ + +static void dump(std::nullptr_t, string &out) { + out += "null"; +} + +static void dump(double value, string &out) { + char buf[32]; + snprintf(buf, sizeof buf, "%.17g", value); + out += buf; +} + +static void dump(int value, string &out) { + char buf[32]; + snprintf(buf, sizeof buf, "%d", value); + out += buf; +} + +static void dump(bool value, string &out) { + out += value ? "true" : "false"; +} + +static void dump(const string &value, string &out) { + out += '"'; + for (size_t i = 0; i < value.length(); i++) { + const char ch = value[i]; + if (ch == '\\') { + out += "\\\\"; + } else if (ch == '"') { + out += "\\\""; + } else 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 ((uint8_t)ch <= 0x1f) { + char buf[8]; + snprintf(buf, sizeof buf, "\\u%04x", ch); + out += buf; + } else if ((uint8_t)ch == 0xe2 && (uint8_t)value[i+1] == 0x80 + && (uint8_t)value[i+2] == 0xa8) { + out += "\\u2028"; + i += 2; + } else if ((uint8_t)ch == 0xe2 && (uint8_t)value[i+1] == 0x80 + && (uint8_t)value[i+2] == 0xa9) { + out += "\\u2029"; + i += 2; + } else { + out += ch; + } + } + out += '"'; +} + +static void dump(const Json::array &values, string &out) { + bool first = true; + out += "["; + for (auto &value : values) { + if (!first) + out += ", "; + value.dump(out); + first = false; + } + out += "]"; +} + +static void dump(const Json::object &values, string &out) { + bool first = true; + out += "{"; + for (const std::pair &kv : values) { + if (!first) + out += ", "; + dump(kv.first, out); + out += ": "; + kv.second.dump(out); + first = false; + } + out += "}"; +} + +void Json::dump(string &out) const { + m_ptr->dump(out); +} + +/* * * * * * * * * * * * * * * * * * * * + * Value wrappers + */ + +template +class Value : public JsonValue { +protected: + + // Constructors + Value(const T &value) : m_value(value) {} + Value(T &&value) : m_value(move(value)) {} + + // Get type tag + Json::Type type() const { + return tag; + } + + // Comparisons + bool equals(const JsonValue * other) const { + return m_value == reinterpret_cast *>(other)->m_value; + } + bool less(const JsonValue * other) const { + return m_value < reinterpret_cast *>(other)->m_value; + } + + const T m_value; + void dump(string &out) const { json11::dump(m_value, out); } +}; + +class JsonDouble final : public Value { + double number_value() const { return m_value; } + int int_value() const { return m_value; } + bool equals(const JsonValue * other) const { return m_value == other->number_value(); } + bool less(const JsonValue * other) const { return m_value < other->number_value(); } +public: + JsonDouble(double value) : Value(value) {} +}; + +class JsonInt final : public Value { + double number_value() const { return m_value; } + int int_value() const { return m_value; } + bool equals(const JsonValue * other) const { return m_value == other->number_value(); } + bool less(const JsonValue * other) const { return m_value < other->number_value(); } +public: + JsonInt(double value) : Value(value) {} +}; + +class JsonBoolean final : public Value { + bool bool_value() const { return m_value; } +public: + JsonBoolean(bool value) : Value(value) {} +}; + +class JsonString final : public Value { + const string &string_value() const { return m_value; } +public: + JsonString(const string &value) : Value(value) {} + JsonString(string &&value) : Value(move(value)) {} +}; + +class JsonArray final : public Value { + const Json::array &array_items() const { return m_value; } + const Json & operator[](size_t i) const; +public: + JsonArray(const Json::array &value) : Value(value) {} + JsonArray(Json::array &&value) : Value(move(value)) {} +}; + +class JsonObject final : public Value { + const Json::object &object_items() const { return m_value; } + const Json & operator[](const string &key) const; +public: + JsonObject(const Json::object &value) : Value(value) {} + JsonObject(Json::object &&value) : Value(move(value)) {} +}; + +class JsonNull final : public Value { +public: + JsonNull() : Value(nullptr) {} +}; + +/* * * * * * * * * * * * * * * * * * * * + * Constructors + */ + +static const std::shared_ptr obj_null(make_shared()); +static const std::shared_ptr obj_true(make_shared(true)); +static const std::shared_ptr obj_false(make_shared(false)); + +Json::Json() noexcept : m_ptr(obj_null) {} +Json::Json(std::nullptr_t) noexcept : m_ptr(obj_null) {} +Json::Json(double value) : m_ptr(make_shared(value)) {} +Json::Json(int value) : m_ptr(make_shared(value)) {} +Json::Json(bool value) : m_ptr(value ? obj_true : obj_false) {} +Json::Json(const string &value) : m_ptr(make_shared(value)) {} +Json::Json(string &&value) : m_ptr(make_shared(move(value))) {} +Json::Json(const char * value) : m_ptr(make_shared(value)) {} +Json::Json(const Json::array &values) : m_ptr(make_shared(values)) {} +Json::Json(Json::array &&values) : m_ptr(make_shared(move(values))) {} +Json::Json(const Json::object &values) : m_ptr(make_shared(values)) {} +Json::Json(Json::object &&values) : m_ptr(make_shared(move(values))) {} + +/* * * * * * * * * * * * * * * * * * * * + * Accessors + */ + +static const string empty_string; +static const vector empty_vector; +static const map empty_map; +static const Json json_null; + +Json::Type Json::type() const { return m_ptr->type(); } +double Json::number_value() const { return m_ptr->number_value(); } +int Json::int_value() const { return m_ptr->int_value(); } +bool Json::bool_value() const { return m_ptr->bool_value(); } +const string & Json::string_value() const { return m_ptr->string_value(); } +const vector & Json::array_items() const { return m_ptr->array_items(); } +const map & Json::object_items() const { return m_ptr->object_items(); } +const Json & Json::operator[] (size_t i) const { return (*m_ptr)[i]; } +const Json & Json::operator[] (const string &key) const { return (*m_ptr)[key]; } + +double JsonValue::number_value() const { return 0; } +int JsonValue::int_value() const { return 0; } +bool JsonValue::bool_value() const { return false; } +const string & JsonValue::string_value() const { return empty_string; } +const vector & JsonValue::array_items() const { return empty_vector; } +const map & JsonValue::object_items() const { return empty_map; } +const Json & JsonValue::operator[] (size_t) const { return json_null; } +const Json & JsonValue::operator[] (const string &) const { return json_null; } + +const Json & JsonObject::operator[] (const string &key) const { + auto iter = m_value.find(key); + return (iter == m_value.end()) ? json_null : iter->second; +} +const Json & JsonArray::operator[] (size_t i) const { + if (i >= m_value.size()) return json_null; + else return m_value[i]; +} + +/* * * * * * * * * * * * * * * * * * * * + * Comparison + */ + +bool Json::operator== (const Json &other) const { + if (m_ptr->type() != other.m_ptr->type()) + return false; + + return m_ptr->equals(other.m_ptr.get()); +} + +bool Json::operator< (const Json &other) const { + if (m_ptr->type() != other.m_ptr->type()) + return m_ptr->type() < other.m_ptr->type(); + + return m_ptr->less(other.m_ptr.get()); +} + +/* * * * * * * * * * * * * * * * * * * * + * Parsing + */ + +/* esc(c) + * + * Format char c suitable for printing in an error message. + */ +static inline string esc(char c) { + char buf[12]; + if ((uint8_t)c >= 0x20 && (uint8_t)c <= 0x7f) { + snprintf(buf, sizeof buf, "'%c' (%d)", c, c); + } else { + snprintf(buf, sizeof buf, "(%d)", c); + } + return string(buf); +} + +static inline bool in_range (int x, int lower, int upper) { + return (x >= lower && x <= upper); +} + +/* JsonParser + * + * Object that tracks all state of an in-progress parse. + */ +struct JsonParser { + + /* State + */ + const string &str; + size_t i; + string &err; + bool failed; + + /* fail(msg, err_ret = Json()) + * + * Mark this parse as failed. + */ + Json fail(string &&msg) { + return fail(move(msg), Json()); + } + + template + T fail(string &&msg, const T err_ret) { + if (!failed) + err = std::move(msg); + failed = true; + return err_ret; + } + + /* consume_whitespace() + * + * Advance until the current character is non-whitespace. + */ + void consume_whitespace() { + while (str[i] == ' ' || str[i] == '\r' || str[i] == '\n' || str[i] == '\t') + i++; + } + + /* get_next_token() + * + * Return the next non-whitespace character. If the end of the input is reached, + * flag an error and return 0. + */ + char get_next_token() { + consume_whitespace(); + if (i == str.size()) + return fail("unexpected end of input", 0); + + return str[i++]; + } + + /* encode_utf8(pt, out) + * + * Encode pt as UTF-8 and add it to out. + */ + void encode_utf8(long pt, string & out) { + if (pt < 0) + return; + + if (pt < 0x80) { + out += pt; + } else if (pt < 0x800) { + out += (pt >> 6) | 0xC0; + out += (pt & 0x3F) | 0x80; + } else if (pt < 0x10000) { + out += (pt >> 12) | 0xE0; + out += ((pt >> 6) & 0x3F) | 0x80; + out += (pt & 0x3F) | 0x80; + } else { + out += (pt >> 18) | 0xF0; + out += ((pt >> 12) & 0x3F) | 0x80; + out += ((pt >> 6) & 0x3F) | 0x80; + out += (pt & 0x3F) | 0x80; + } + } + + /* parse_string() + * + * Parse a string, starting at the current position. + */ + string parse_string() { + string out; + long last_escaped_codepoint = -1; + while (true) { + if (i == str.size()) + return fail("unexpected end of input in string", ""); + + char ch = str[i++]; + + if (ch == '"') { + encode_utf8(last_escaped_codepoint, out); + return out; + } + + if (in_range(ch, 0, 0x1f)) + return fail("unescaped " + esc(ch) + " in string", ""); + + // The usual case: non-escaped characters + if (ch != '\\') { + encode_utf8(last_escaped_codepoint, out); + last_escaped_codepoint = -1; + out += ch; + continue; + } + + // Handle escapes + if (i == str.size()) + return fail("unexpected end of input in string", ""); + + ch = str[i++]; + + if (ch == 'u') { + // Extract 4-byte escape sequence + 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')) + return fail("bad \\u escape: " + esc, ""); + } + + long codepoint = strtol(esc.data(), nullptr, 16); + + // JSON specifies that characters outside the BMP shall be encoded as a pair + // of 4-hex-digit \u escapes encoding their surrogate pair components. Check + // whether we're in the middle of such a beast: the previous codepoint was an + // escaped lead (high) surrogate, and this is a trail (low) surrogate. + if (in_range(last_escaped_codepoint, 0xD800, 0xDBFF) + && in_range(codepoint, 0xDC00, 0xDFFF)) { + // Reassemble the two surrogate pairs into one astral-plane character, per + // 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; + } + + i += 4; + 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::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 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 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::parse_multi(const string &in, string &err) { + JsonParser parser { in, 0, err, false }; + + vector 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 diff --git a/json11.hpp b/json11.hpp new file mode 100644 index 0000000..a2fa5c7 --- /dev/null +++ b/json11.hpp @@ -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 +#include +#include +#include +#include + +namespace json11 { + +class JsonValue; + +class Json final { +public: + // Types + enum Type { + NUL, NUMBER, BOOL, STRING, ARRAY, OBJECT + }; + + // Array and object typedefs + typedef std::vector array; + typedef std::map 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 + Json(const T & t) : Json(t.to_json()) {} + + // Implicit constructor: map-like objects (std::map, std::unordered_map, etc) + template ().begin()->first)>::value + && std::is_constructible().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 ().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 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> shape; + bool has_shape(const shape & types, std::string & err) const; + +private: + std::shared_ptr 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 diff --git a/test.cpp b/test.cpp new file mode 100644 index 0000000..f34c4a0 --- /dev/null +++ b/test.cpp @@ -0,0 +1,100 @@ +#include +#include +#include +#include +#include "json11.hpp" +#include + +using namespace json11; +using std::string; + +// Check that Json has the properties we want. +#include +#define CHECK_TRAIT(x) static_assert(std::x::value, #x) +CHECK_TRAIT(is_nothrow_constructible); +CHECK_TRAIT(is_nothrow_default_constructible); +CHECK_TRAIT(is_copy_constructible); +CHECK_TRAIT(is_nothrow_move_constructible); +CHECK_TRAIT(is_copy_assignable); +CHECK_TRAIT(is_nothrow_move_assignable); +CHECK_TRAIT(is_nothrow_destructible); + +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 points = { { 1, 2 }, { 10, 20 }, { 100, 200 } }; + std::string points_json = Json(points).dump(); + printf("%s\n", points_json.c_str()); +}