/* Copyright (c) 2007-2008 John W Wilkinson
This source code can be used for any purpose as long as
this comment is retained. */
// json spirit version 2.05
#include "json_spirit_reader.h"
#include "json_spirit_value.h"
//#define BOOST_SPIRIT_THREADSAFE // uncomment for multithreaded use, requires linking to boost.thead
#include <boost/bind.hpp>
#include <boost/function.hpp>
#include <boost/spirit/core.hpp>
#include <boost/spirit/utility/confix.hpp>
#include <boost/spirit/utility/escape_char.hpp>
#include <boost/spirit/utility/lists.hpp>
using namespace json_spirit;
using namespace std;
using namespace boost;
using namespace boost::spirit;
namespace
{
const int_parser< int64_t > int64_p = int_parser< int64_t >();
// this class solely allows its inner classes and methods to
// be conveniently templatised by Value type and dependent types
//
template< class Value_t >
struct Reader
{
typedef typename Value_t::String_type String_t;
typedef typename Value_t::Object Object_t;
typedef typename Value_t::Array Array_t;
typedef typename String_t::value_type Char_t;
typedef typename String_t::const_iterator Iter_t;
typedef Pair_impl< String_t > Pair_t;
typedef std::basic_istream< Char_t > Istream_t;
// this class's methods get called by the spirit parse resulting
// in the creation of a JSON object or array
//
class Semantic_actions
{
public:
Semantic_actions( Value_t& value )
: value_( value )
, current_p_( 0 )
{
}
void begin_obj( Char_t c )
{
assert( c == '{' );
begin_compound< Object_t >();
}
void end_obj( Char_t c )
{
assert( c == '}' );
end_compound();
}
void begin_array( Char_t c )
{
assert( c == '[' );
begin_compound< Array_t >();
}
void end_array( Char_t c )
{
assert( c == ']' );
end_compound();
}
void new_name( Iter_t str, Iter_t end )
{
assert( current_p_->type() == obj_type );
name_ = get_str( str, end );
}
void new_str( Iter_t str, Iter_t end )
{
add_to_current( get_str( str, end ) );
}
void new_true( Iter_t str, Iter_t end )
{
assert( is_eq( str, end, "true" ) );
add_to_current( true );
}
void new_false( Iter_t str, Iter_t end )
{
assert( is_eq( str, end, "false" ) );
add_to_current( false );
}
void new_null( Iter_t str, Iter_t end )
{
assert( is_eq( str, end, "null" ) );
add_to_current( Value_t() );
}
void new_int( int64_t i )
{
add_to_current( i );
}
void new_real( double d )
{
add_to_current( d );
}
private:
void add_first( const Value_t& value )
{
assert( current_p_ == 0 );
value_ = value;
current_p_ = &value_;
}
template< class Array_or_obj >
void begin_compound()
{
if( current_p_ == 0 )
{
add_first( Array_or_obj() );
}
else
{
stack_.push_back( current_p_ );
Array_or_obj new_array_or_obj; // avoid copy by building new array or object in place
add_to_current( new_array_or_obj );
if( current_p_->type() == array_type )
{
current_p_ = ¤t_p_->get_array().back();
}
else
{
current_p_ = ¤t_p_->get_obj().back().value_;
}
}
}
void end_compound()
{
if( current_p_ != &value_ )
{
current_p_ = stack_.back();
stack_.pop_back();
}
}
void add_to_current( const Value_t& value )
{
if( !current_p_ )
{
add_first( value );
}
else if( current_p_->type() == array_type )
{
current_p_->get_array().push_back( value );
}
else if( current_p_->type() == obj_type )
{
current_p_->get_obj().push_back( Pair_t( name_, value ) );
}
}
Value_t& value_; // this is the object or array that is being created
Value_t* current_p_; // the child object or array that is currently being constructed
vector< Value_t* > stack_; // previous child objects and arrays
String_t name_; // of current name/value pair
};
// the spirit grammer
//
class Json_grammer : public grammar< Json_grammer >
{
public:
Json_grammer( Semantic_actions& semantic_actions )
: actions_( semantic_actions )
{
}
template< typename ScannerT >
struct definition
{
definition( const Json_grammer& self )
{
// need to convert the semantic action class methods to functors with the
// parameter signature expected by spirit
typedef function< void( Char_t ) > Char_action;
typedef function< void( Iter_t, Iter_t ) > Str_action;
typedef function< void( double ) > Real_action;
typedef function< void( int64_t ) > Int_action;
Char_action begin_obj ( bind( &Semantic_actions::begin_obj, &self.actions_, _1 ) );
Char_action end_obj ( bind( &Semantic_actions::end_obj, &self.actions_, _1 ) );
Char_action begin_array( bind( &Semantic_actions::begin_array, &self.actions_, _1 ) );
Char_action end_array ( bind( &Semantic_actions::end_array, &self.actions_, _1 ) );
Str_action new_name ( bind( &Semantic_actions::new_name, &self.actions_, _1, _2 ) );
Str_action new_str ( bind( &Semantic_actions::new_str, &self.actions_, _1, _2 ) );
Str_action new_true ( bind( &Semantic_actions::new_true, &self.actions_, _1, _2 ) );
Str_action new_false ( bind( &Semantic_actions::new_false, &self.actions_, _1, _2 ) );
Str_action new_null ( bind( &Semantic_actions::new_null, &self.actions_, _1, _2 ) );
Real_action new_real ( bind( &Semantic_actions::new_real, &self.actions_, _1 ) );
Int_action new_int ( bind( &Semantic_actions::new_int, &self.actions_, _1 ) );
json_
= value_ >> end_p
;
object_
= confix_p
(
ch_p('{')[ begin_obj ],
!members_,
ch_p('}')[ end_obj ]
)
;
members_
= pair_ >> *( ',' >> pair_ )
;
pair_
= string_[ new_name ]
>> ':'
>> value_
;
value_
= string_[ new_str ]
| number_
| object_
| array_
| str_p( "true" ) [ new_true ]
| str_p( "false" )[ new_false ]
| str_p( "null" ) [ new_null ]
;
array_
= confix_p
(
ch_p('[')[ begin_array ],
!elements_,
ch_p(']')[ end_array ]
)
;
elements_
= value_ >> *( ',' >> value_ )
;
string_
= lexeme_d // this causes white space inside a string to be retained
[
confix_p
(
'"',
*lex_escape_ch_p,
'"'
)
]
;
number_
= strict_real_p[ new_real ]
| int64_p [ new_int ]
;
}
rule< ScannerT > json_, object_, members_, pair_, array_, elements_, value_, string_, number_;
const rule< ScannerT >& start() const { return json_; }
};
Semantic_actions& actions_;
};
static bool is_eq( Iter_t str, Iter_t end, const char* c_str )
{
const String_t s1( str, end );
const string s2( c_str );
if( s1.length() != s2.length() ) return false;
for( typename String_t::size_type i = 0; i < s1.length(); ++i )
{
if( s1[i] != s2[i] ) return false;
}
return true;
}
static Char_t hex_to_num( const Char_t c )
{
if( ( c >= '0' ) && ( c <= '9' ) ) return c - '0';
if( ( c >= 'a' ) && ( c <= 'f' ) ) return c - 'a' + 10;
if( ( c >= 'A' ) && ( c <= 'F' ) ) return c - 'A' + 10;
return 0;
}
static Char_t hex_str_to_char( Iter_t& str )
{
const Char_t c1( *( ++str ) );
const Char_t c2( *( ++str ) );
return hex_to_num( c1 ) * 0x10 + hex_to_num( c2 );
}
static Char_t unicode_str_to_char( Iter_t& str )
{
const Char_t c1( *( ++str ) );
const Char_t c2( *( ++str ) );
const Char_t c3( *( ++str ) );
const Char_t c4( *( ++str ) );
return hex_to_num( c1 ) * 0x1000 + hex_to_num( c2 ) * 0x100 + hex_to_num( c3 ) * 0x10 + hex_to_num( c4 );
}
static String_t substitute_esc_chars( Iter_t str, Iter_t end )
{
if( end - str < 2 ) return String_t( str, end );
String_t result;
Iter_t end_minus_1( end - 1 );
for( Iter_t i = str; i < end; ++i )
{
const Char_t c1( *i );
if( ( c1 == '\\' ) && ( i != end_minus_1 ) )
{
++i;
const Char_t c2( *i );
switch( c2 )
{
case 't': result += '\t'; break;
case 'b': result += '\b'; break;
case 'f': result += '\f'; break;
case 'n': result += '\n'; break;
case 'r': result += '\r'; break;
case '\\': result += '\\'; break;
case '/': result += '/'; break;
case '"': result += '"'; break;
case 'x':
{
if( end - i >= 3 ) // expecting "xHH..."
{
result += hex_str_to_char( i );
}
break;
}
case 'u':
{
if( end - i >= 5 ) // expecting "uHHHH..."
{
result += unicode_str_to_char( i );
}
break;
}
}
}
else
{
result += c1;
}
}
return result;
}
static String_t get_str( Iter_t str, Iter_t end )
{
assert( end - str >= 2 );
Iter_t str_without_quotes( str + 1 );
Iter_t end_without_quotes( end - 1 );
return substitute_esc_chars( str_without_quotes, end_without_quotes );
}
static void stream_to_string( Istream_t& is, String_t& s )
{
typedef istream_iterator< Char_t, Char_t > istream_iter;
is.unsetf( ios::skipws );
copy( istream_iter( is ), istream_iter(), back_inserter( s ) );
}
static bool read_string( const String_t& s, Value_t& value )
{
Semantic_actions semantic_actions( value );
parse_info< Iter_t > info = parse( s.begin(), s.end(),
Json_grammer( semantic_actions ),
space_p );
return info.full;
}
static bool read_stream( Istream_t& is, Value_t& value )
{
String_t s;
stream_to_string( is, s );
return read_string( s, value );
}
};
}
bool json_spirit::read( const std::string& s, Value& value )
{
return Reader< Value >::read_string( s, value );
}
bool json_spirit::read( std::istream& is, Value& value )
{
return Reader< Value >::read_stream( is, value );
}
#ifndef BOOST_NO_STD_WSTRING
bool json_spirit::read( const std::wstring& s, wValue& value )
{
return Reader< wValue >::read_string( s, value );
}
bool json_spirit::read( std::wistream& is, wValue& value )
{
return Reader< wValue >::read_stream( is, value );
}
#endif