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  1. 1
      .gitignore
  2. 2
      Makefile
  3. 42
      README.md
  4. 674
      json11.cpp
  5. 187
      json11.hpp
  6. 100
      test.cpp

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test

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test: json11.cpp json11.hpp test.cpp
clang++ -O -std=c++11 -stdlib=libc++ json11.cpp test.cpp -o test -fno-rtti -fno-exceptions

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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<Point> 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.

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/* 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 <cassert>
#include <cstdlib>
#include <cstdio>
#include <limits>
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<string, Json> &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 <Json::Type tag, typename T>
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<const Value<tag, T> *>(other)->m_value;
}
bool less(const JsonValue * other) const {
return m_value < reinterpret_cast<const Value<tag, T> *>(other)->m_value;
}
const T m_value;
void dump(string &out) const { json11::dump(m_value, out); }
};
class JsonDouble final : public Value<Json::NUMBER, double> {
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<Json::NUMBER, int> {
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<Json::BOOL, bool> {
bool bool_value() const { return m_value; }
public:
JsonBoolean(bool value) : Value(value) {}
};
class JsonString final : public Value<Json::STRING, string> {
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<Json::ARRAY, Json::array> {
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<Json::OBJECT, Json::object> {
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<Json::NUL, std::nullptr_t> {
public:
JsonNull() : Value(nullptr) {}
};
/* * * * * * * * * * * * * * * * * * * *
* Constructors
*/
static const std::shared_ptr<JsonValue> obj_null(make_shared<JsonNull>());
static const std::shared_ptr<JsonValue> obj_true(make_shared<JsonBoolean>(true));
static const std::shared_ptr<JsonValue> obj_false(make_shared<JsonBoolean>(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<JsonDouble>(value)) {}
Json::Json(int value) : m_ptr(make_shared<JsonInt>(value)) {}
Json::Json(bool value) : m_ptr(value ? obj_true : obj_false) {}
Json::Json(const string &value) : m_ptr(make_shared<JsonString>(value)) {}
Json::Json(string &&value) : m_ptr(make_shared<JsonString>(move(value))) {}
Json::Json(const char * value) : m_ptr(make_shared<JsonString>(value)) {}
Json::Json(const Json::array &values) : m_ptr(make_shared<JsonArray>(values)) {}
Json::Json(Json::array &&values) : m_ptr(make_shared<JsonArray>(move(values))) {}
Json::Json(const Json::object &values) : m_ptr(make_shared<JsonObject>(values)) {}
Json::Json(Json::object &&values) : m_ptr(make_shared<JsonObject>(move(values))) {}
/* * * * * * * * * * * * * * * * * * * *
* Accessors
*/
static const string empty_string;
static const vector<Json> empty_vector;
static const map<string, Json> 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> & Json::array_items() const { return m_ptr->array_items(); }
const map<string, Json> & 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<Json> & JsonValue::array_items() const { return empty_vector; }
const map<string, Json> & 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 <typename T>
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<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

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/* 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

100
test.cpp
View File

@ -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());
}
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