kicad/gerbview/json11.cpp

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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 <cmath>
#include <cstdlib>
#include <cstdio>
#include <limits>
namespace json11 {
static const int max_depth = 200;
using std::string;
using std::vector;
using std::map;
using std::make_shared;
using std::initializer_list;
using std::move;
/* 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, string& out )
{
out += "null";
}
static void dump( double value, string& out )
{
if( std::isfinite( value ) )
{
char buf[32];
snprintf( buf, sizeof buf, "%.17g", value );
out += buf;
}
else
{
out += "null";
}
}
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( 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, 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, 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 += "}";
}
void Json::dump( string& out ) const
{
m_ptr->dump( out );
}
/* * * * * * * * * * * * * * * * * * * *
* Value wrappers
*/
template <Json::Type tag, typename T>
class Value : public JsonValue
{
protected:
// Constructors
explicit Value( const T& value ) : m_value( value ) {}
explicit Value( T&& value ) : m_value( 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( 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); }
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, int>
{
double number_value() const override { return m_value; }
int int_value() const override { return 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, string>
{
const string& string_value() const override { return m_value; }
public:
explicit JsonString( const string& value ) : Value( value ) {}
explicit JsonString( string&& value ) : Value( 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( 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 string& key ) const override;
public:
explicit JsonObject( const Json::object& value ) : Value( value ) {}
explicit JsonObject( Json::object&& value ) : Value( 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 = make_shared<JsonNull>();
const std::shared_ptr<JsonValue> t = make_shared<JsonBoolean>( true );
const std::shared_ptr<JsonValue> f = make_shared<JsonBoolean>( false );
const string empty_string;
const vector<Json> empty_vector;
const map<string, Json> empty_map;
Statics() {}
};
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
*/
Json::Json() noexcept : m_ptr( statics().null )
{
}
Json::Json( std::nullptr_t ) noexcept : m_ptr( statics().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 ? statics().t : statics().f )
{
}
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
*/
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 statics().empty_string;
}
const vector<Json>& JsonValue::array_items() const
{
return statics().empty_vector;
}
const map<string, Json>& JsonValue::object_items() const
{
return statics().empty_map;
}
const Json& JsonValue::operator[]( size_t ) const
{
return static_null();
}
const Json& JsonValue::operator[]( const string& ) const
{
return static_null();
}
const Json& JsonObject::operator[]( const string& key ) const
{
auto iter = m_value.find( key );
return ( iter == m_value.end() ) ? static_null() : iter->second;
}
const Json& JsonArray::operator[]( size_t i ) const
{
if( i >= m_value.size() )
return static_null();
else
return m_value[i];
}
/* * * * * * * * * * * * * * * * * * * *
* Comparison
*/
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() );
}
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 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 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 string& str;
size_t i;
string& err;
bool failed;
const JsonParse strategy;
/* 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++;
}
/* 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 (char) 0;
if( i == str.size() )
return fail( "unexpected end of input", (char) 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 += 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 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 );
// 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::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::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 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 == '{' )
{
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( 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 == '[' )
{
vector<Json> data;
ch = get_next_token();
if( ch == ']' )
return data;
while( 1 )
{
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 {
Json Json::parse( const string& in, 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;
}
// Documented in json11.hpp
vector<Json> Json::parse_multi( const string& in,
std::string::size_type& parser_stop_pos,
string& err,
JsonParse strategy )
{
JsonParser parser {
in, 0, err, false, strategy
};
parser_stop_pos = 0;
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;
}
/* * * * * * * * * * * * * * * * * * * *
* 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