/* 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.
*
* A note on numbers - JSON specifies the syntax of number formatting but not its semantics,
* so some JSON implementations distinguish between integers and floating-point numbers, while
* some don't. In json11, we choose the latter. Because some JSON implementations (namely
* Javascript itself) treat all numbers as the same type, distinguishing the two leads
* to JSON that will be *silently* changed by a round-trip through those implementations.
* Dangerous! To avoid that risk, json11 stores all numbers as double internally, but also
* provides integer helpers.
*
* Fortunately, double-precision IEEE754 ('double') can precisely store any integer in the
* range +/-2^53, which includes every 'int' on most systems. (Timestamps often use int64
* or long long to avoid the Y2038K problem; a double storing microseconds since some epoch
* will be exact for +/- 275 years.)
*/
/* 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 <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <initializer_list>
#include <iosfwd>
#include <limits>
#include <map>
#include <memory>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>
#ifdef _MSC_VER
#if _MSC_VER <= 1800 // VS 2013
#ifndef noexcept
#define noexcept throw()
#endif
#ifndef snprintf
#define snprintf _snprintf_s
#endif
#endif
#endif
namespace json11 {
enum JsonParse { STANDARD, COMMENTS };
class JsonValue;
class Json final {
public:
// Types
enum Type { NUL, NUMBER, BOOL, STRING, ARRAY, OBJECT };
// Array and object typedefs
using array = std::vector<Json>;
using object = std::map<std::string, Json>;
// Constructors for the various types of JSON value.
Json() noexcept; // NUL
Json(std::nullptr_t) noexcept; // NUL
Json(double value); // NUMBER
Json(long long 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;
long long long_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 array, 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, JsonParse strategy = JsonParse::STANDARD);
static Json parse(const char* in, std::string& err, JsonParse strategy = JsonParse::STANDARD) {
if (in == nullptr) {
err = "null input";
return nullptr;
}
return parse(std::string(in), err, strategy);
}
// Parse multiple objects, concatenated or separated by whitespace
static std::vector<Json> parse_multi(const std::string& in, std::string::size_type& parser_stop_pos,
std::string& err, JsonParse strategy = JsonParse::STANDARD);
static inline std::vector<Json> parse_multi(
const std::string& in, std::string& err, JsonParse strategy = JsonParse::STANDARD) {
std::string::size_type parser_stop_pos;
return parse_multi(in, parser_stop_pos, err, strategy);
}
bool operator==(const Json& rhs) const;
bool operator<(const Json& rhs) const;
bool operator!=(const Json& rhs) const {
return !(*this == rhs);
}
bool operator<=(const Json& rhs) const {
return !(rhs < *this);
}
bool operator>(const Json& rhs) const {
return (rhs < *this);
}
bool operator>=(const Json& rhs) const {
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.
*/
using shape = std::initializer_list<std::pair<std::string, Type>>;
bool has_shape(const shape& types, std::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;
}
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 long long long_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() = default;
};
static const int max_depth = 200;
/* Helper for representing null - just a do-nothing struct, plus comparison
* operators so the helpers in JsonValue work. We can't use nullptr_t because
* it may not be orderable.
*/
struct NullStruct {
bool operator==(NullStruct) const {
return true;
}
bool operator<(NullStruct) const {
return false;
}
};
/* * * * * * * * * * * * * * * * * * * *
* Serialization
*/
static void dump(NullStruct, std::string& out) {
out += "null";
}
static void dump(double value, std::string& out) {
if (std::isfinite(value)) {
char buf[32];
snprintf(buf, sizeof buf, "%.17g", value);
out += buf;
} else {
out += "null";
}
}
static void dump(long long value, std::string& out) {
char buf[32];
snprintf(buf, sizeof buf, "%lld", value);
out += buf;
}
static void dump(bool value, std::string& out) {
out += value ? "true" : "false";
}
static void dump(const std::string& value, std::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 (static_cast<uint8_t>(ch) <= 0x1f) {
char buf[8];
snprintf(buf, sizeof buf, "\\u%04x", ch);
out += buf;
} else if (static_cast<uint8_t>(ch) == 0xe2 && static_cast<uint8_t>(value[i + 1]) == 0x80 &&
static_cast<uint8_t>(value[i + 2]) == 0xa8) {
out += "\\u2028";
i += 2;
} else if (static_cast<uint8_t>(ch) == 0xe2 && static_cast<uint8_t>(value[i + 1]) == 0x80 &&
static_cast<uint8_t>(value[i + 2]) == 0xa9) {
out += "\\u2029";
i += 2;
} else {
out += ch;
}
}
out += '"';
}
static void dump(const Json::array& values, std::string& out) {
bool first = true;
out += "[";
for (const auto& value : values) {
if (!first) out += ", ";
value.dump(out);
first = false;
}
out += "]";
}
static void dump(const Json::object& values, std::string& out) {
bool first = true;
out += "{";
for (const auto& kv : values) {
if (!first) out += ", ";
dump(kv.first, out);
out += ": ";
kv.second.dump(out);
first = false;
}
out += "}";
}
inline void Json::dump(std::string& out) const {
m_ptr->dump(out);
}
/* * * * * * * * * * * * * * * * * * * *
* Value wrappers
*/
template <Json::Type tag, typename T>
class Value : public JsonValue {
protected:
// Constructors
explicit Value(T value) : m_value(std::move(value)) {}
// Get type tag
Json::Type type() const override {
return tag;
}
// Comparisons
bool equals(const JsonValue* other) const override {
return m_value == static_cast<const Value<tag, T>*>(other)->m_value;
}
bool less(const JsonValue* other) const override {
return m_value < static_cast<const Value<tag, T>*>(other)->m_value;
}
const T m_value;
void dump(std::string& out) const override {
json11::dump(m_value, out);
}
};
class JsonDouble final : public Value<Json::NUMBER, double> {
double number_value() const override {
return m_value;
}
int int_value() const override {
return static_cast<int>(m_value);
}
long long long_value() const override {
return static_cast<long long>(m_value);
}
bool equals(const JsonValue* other) const override {
return m_value == other->number_value();
}
bool less(const JsonValue* other) const override {
return m_value < other->number_value();
}
public:
explicit JsonDouble(double value) : Value(value) {}
};
class JsonInt final : public Value<Json::NUMBER, long long> {
double number_value() const override {
return m_value;
}
int int_value() const override {
return m_value;
}
long long long_value() const override {
return static_cast<long long>(m_value);
}
bool equals(const JsonValue* other) const override {
return m_value == other->number_value();
}
bool less(const JsonValue* other) const override {
return m_value < other->number_value();
}
public:
explicit JsonInt(int value) : Value(value) {}
};
class JsonBoolean final : public Value<Json::BOOL, bool> {
bool bool_value() const override {
return m_value;
}
public:
explicit JsonBoolean(bool value) : Value(value) {}
};
class JsonString final : public Value<Json::STRING, std::string> {
const std::string& string_value() const override {
return m_value;
}
public:
explicit JsonString(const std::string& value) : Value(value) {}
explicit JsonString(std::string&& value) : Value(std::move(value)) {}
};
class JsonArray final : public Value<Json::ARRAY, Json::array> {
const Json::array& array_items() const override {
return m_value;
}
const Json& operator[](size_t i) const override;
public:
explicit JsonArray(const Json::array& value) : Value(value) {}
explicit JsonArray(Json::array&& value) : Value(std::move(value)) {}
};
class JsonObject final : public Value<Json::OBJECT, Json::object> {
const Json::object& object_items() const override {
return m_value;
}
const Json& operator[](const std::string& key) const override;
public:
explicit JsonObject(const Json::object& value) : Value(value) {}
explicit JsonObject(Json::object&& value) : Value(std::move(value)) {}
};
class JsonNull final : public Value<Json::NUL, NullStruct> {
public:
JsonNull() : Value({}) {}
};
/* * * * * * * * * * * * * * * * * * * *
* Static globals - static-init-safe
*/
struct Statics {
const std::shared_ptr<JsonValue> null = std::make_shared<JsonNull>();
const std::shared_ptr<JsonValue> t = std::make_shared<JsonBoolean>(true);
const std::shared_ptr<JsonValue> f = std::make_shared<JsonBoolean>(false);
const std::string empty_string{};
const std::vector<Json> empty_vector{};
const std::map<std::string, Json> empty_map{};
Statics() = default;
};
static const Statics& statics() {
static const Statics s{};
return s;
}
static const Json& static_null() {
// This has to be separate, not in Statics, because Json() accesses statics().null.
static const Json json_null;
return json_null;
}
/* * * * * * * * * * * * * * * * * * * *
* Constructors
*/
inline Json::Json() noexcept : m_ptr(statics().null) {}
inline Json::Json(std::nullptr_t) noexcept : m_ptr(statics().null) {}
inline Json::Json(double value) : m_ptr(std::make_shared<JsonDouble>(value)) {}
inline Json::Json(long long value) : m_ptr(std::make_shared<JsonInt>(value)) {}
inline Json::Json(bool value) : m_ptr(value ? statics().t : statics().f) {}
inline Json::Json(const std::string& value) : m_ptr(std::make_shared<JsonString>(value)) {}
inline Json::Json(std::string&& value) : m_ptr(std::make_shared<JsonString>(std::move(value))) {}
inline Json::Json(const char* value) : m_ptr(std::make_shared<JsonString>(value)) {}
inline Json::Json(const Json::array& values) : m_ptr(std::make_shared<JsonArray>(values)) {}
inline Json::Json(Json::array&& values) : m_ptr(std::make_shared<JsonArray>(std::move(values))) {}
inline Json::Json(const Json::object& values) : m_ptr(std::make_shared<JsonObject>(values)) {}
inline Json::Json(Json::object&& values) : m_ptr(std::make_shared<JsonObject>(std::move(values))) {}
/* * * * * * * * * * * * * * * * * * * *
* Accessors
*/
inline Json::Type Json::type() const {
return m_ptr->type();
}
inline double Json::number_value() const {
return m_ptr->number_value();
}
inline int Json::int_value() const {
return m_ptr->int_value();
}
inline long long Json::long_value() const {
return m_ptr->long_value();
}
inline bool Json::bool_value() const {
return m_ptr->bool_value();
}
inline const std::string& Json::string_value() const {
return m_ptr->string_value();
}
inline const std::vector<Json>& Json::array_items() const {
return m_ptr->array_items();
}
inline const std::map<std::string, Json>& Json::object_items() const {
return m_ptr->object_items();
}
inline const Json& Json::operator[](size_t i) const {
return (*m_ptr)[i];
}
inline const Json& Json::operator[](const std::string& key) const {
return (*m_ptr)[key];
}
inline double JsonValue::number_value() const {
return 0;
}
inline int JsonValue::int_value() const {
return 0;
}
inline long long JsonValue::long_value() const {
return 0;
}
inline bool JsonValue::bool_value() const {
return false;
}
inline const std::string& JsonValue::string_value() const {
return statics().empty_string;
}
inline const std::vector<Json>& JsonValue::array_items() const {
return statics().empty_vector;
}
inline const std::map<std::string, Json>& JsonValue::object_items() const {
return statics().empty_map;
}
inline const Json& JsonValue::operator[](size_t) const {
return static_null();
}
inline const Json& JsonValue::operator[](const std::string&) const {
return static_null();
}
inline const Json& JsonObject::operator[](const std::string& key) const {
auto iter = m_value.find(key);
return (iter == m_value.end()) ? static_null() : iter->second;
}
inline const Json& JsonArray::operator[](size_t i) const {
if (i >= m_value.size()) {
return static_null();
}
return m_value[i];
}
/* * * * * * * * * * * * * * * * * * * *
* Comparison
*/
inline bool Json::operator==(const Json& other) const {
if (m_ptr == other.m_ptr) {
return true;
}
if (m_ptr->type() != other.m_ptr->type()) {
return false;
}
return m_ptr->equals(other.m_ptr.get());
}
inline bool Json::operator<(const Json& other) const {
if (m_ptr == other.m_ptr) {
return false;
}
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 std::string esc(char c) {
char buf[12];
if (static_cast<uint8_t>(c) >= 0x20 && static_cast<uint8_t>(c) <= 0x7f) {
snprintf(buf, sizeof buf, "'%c' (%d)", c, c);
} else {
snprintf(buf, sizeof buf, "(%d)", c);
}
return std::string(buf);
}
static inline bool in_range(long x, long lower, long upper) {
return (x >= lower && x <= upper);
}
namespace {
/* JsonParser
*
* Object that tracks all state of an in-progress parse.
*/
struct JsonParser final {
/* State
*/
const std::string& str;
size_t i;
std::string& err;
bool failed;
const JsonParse strategy;
/* fail(msg, err_ret = Json())
*
* Mark this parse as failed.
*/
Json fail(std::string&& msg) {
return fail(std::move(msg), Json());
}
template <typename T>
T fail(std::string&& msg, 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++;
}
}
/* consume_comment()
*
* Advance comments (c-style inline and multiline).
*/
bool consume_comment() {
bool comment_found = false;
if (str[i] == '/') {
i++;
if (i == str.size()) {
return fail("unexpected end of input after start of comment", false);
}
if (str[i] == '/') { // inline comment
i++;
// advance until next line, or end of input
while (i < str.size() && str[i] != '\n') {
i++;
}
comment_found = true;
} else if (str[i] == '*') { // multiline comment
i++;
if (i > str.size() - 2)
return fail("unexpected end of input inside multi-line comment", false);
// advance until closing tokens
while (!(str[i] == '*' && str[i + 1] == '/')) {
i++;
if (i > str.size() - 2)
return fail("unexpected end of input inside multi-line comment", false);
}
i += 2;
comment_found = true;
} else {
return fail("malformed comment", false);
}
}
return comment_found;
}
/* consume_garbage()
*
* Advance until the current character is non-whitespace and non-comment.
*/
void consume_garbage() {
consume_whitespace();
if (strategy == JsonParse::COMMENTS) {
bool comment_found = false;
do {
comment_found = consume_comment();
if (failed) {
return;
}
consume_whitespace();
} while (comment_found);
}
}
/* 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_garbage();
if (failed) {
return static_cast<char>(0);
}
if (i == str.size()) {
return fail("unexpected end of input", static_cast<char>(0));
}
return str[i++];
}
/* encode_utf8(pt, out)
*
* Encode pt as UTF-8 and add it to out.
*/
void encode_utf8(long pt, std::string& out) {
if (pt < 0) {
return;
}
if (pt < 0x80) {
out += static_cast<char>(pt);
} else if (pt < 0x800) {
out += static_cast<char>((pt >> 6) | 0xC0);
out += static_cast<char>((pt & 0x3F) | 0x80);
} else if (pt < 0x10000) {
out += static_cast<char>((pt >> 12) | 0xE0);
out += static_cast<char>(((pt >> 6) & 0x3F) | 0x80);
out += static_cast<char>((pt & 0x3F) | 0x80);
} else {
out += static_cast<char>((pt >> 18) | 0xF0);
out += static_cast<char>(((pt >> 12) & 0x3F) | 0x80);
out += static_cast<char>(((pt >> 6) & 0x3F) | 0x80);
out += static_cast<char>((pt & 0x3F) | 0x80);
}
}
/* parse_string()
*
* Parse a std::string, starting at the current position.
*/
std::string parse_string() {
std::string out;
long last_escaped_codepoint = -1;
while (true) {
if (i == str.size()) return fail("unexpected end of input in std::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 std::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 std::string", "");
}
ch = str[i++];
if (ch == 'u') {
// Extract 4-byte escape sequence
std::string esc = str.substr(i, 4);
// Explicitly check length of the substring. The following loop
// relies on std::string returning the terminating NUL when
// accessing str[length]. Checking here reduces brittleness.
if (esc.length() < 4) {
return fail("bad \\u escape: " + esc, "");
}
for (size_t 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) <= static_cast<size_t>(std::numeric_limits<int>::digits10)) {
return std::atoll(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::strtod(str.c_str() + start_pos, nullptr);
}
/* 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 std::string& expected, Json res) {
assert(i != 0);
i--;
if (str.compare(i, expected.length(), expected) == 0) {
i += expected.length();
return res;
} else {
return fail("parse error: expected " + expected + ", got " + str.substr(i, expected.length()));
}
}
/* parse_json()
*
* Parse a JSON object.
*/
Json parse_json(int depth) {
if (depth > max_depth) {
return fail("exceeded maximum nesting depth");
}
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 == '{') {
std::map<std::string, Json> data;
ch = get_next_token();
if (ch == '}') {
return data;
}
while (true) {
if (ch != '"') return fail("expected '\"' in object, got " + esc(ch));
std::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(depth + 1);
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 == '[') {
std::vector<Json> data;
ch = get_next_token();
if (ch == ']') {
return data;
}
while (true) {
i--;
data.push_back(parse_json(depth + 1));
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));
}
};
} // namespace
inline Json Json::parse(const std::string& in, std::string& err, JsonParse strategy) {
JsonParser parser{in, 0, err, false, strategy};
Json result = parser.parse_json(0);
// Check for any trailing garbage
parser.consume_garbage();
if (parser.failed) {
return Json();
}
if (parser.i != in.size()) {
return parser.fail("unexpected trailing " + esc(in[parser.i]));
}
return result;
}
inline std::vector<Json> parse_multi(const std::string& in, std::string::size_type& parser_stop_pos,
std::string& err, JsonParse strategy) {
JsonParser parser{in, 0, err, false, strategy};
parser_stop_pos = 0;
std::vector<Json> json_vec;
while (parser.i != in.size() && !parser.failed) {
json_vec.push_back(parser.parse_json(0));
if (parser.failed) {
break;
}
// Check for another object
parser.consume_garbage();
if (parser.failed) {
break;
}
parser_stop_pos = parser.i;
}
return json_vec;
}
} // namespace json11