PicoJSON + utilities added

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "glm"]
 	path = glm
 	url = https://github.com/g-truc/glm.git
+[submodule "picojson"]
+	path = picojson
+	url = https://github.com/kazuho/picojson.git

.vim.local/ycm_extra_conf.py

@@ -47,6 +47,7 @@ flags = [
     '-I','.',
     '-I','imgui',
     '-I','glm',
+    '-I','picojson',
     '-I','/usr/include/SDL2' ,
     '-D','GLM_ENABLE_EXPERIMENTAL',
 ]

Makefile

@@ -2,7 +2,8 @@ OUTDIR = output
 
 CXXFLAGS += $(shell sdl2-config --cflags) -std=c++14 -Wall -g
 CFLAGS += $(shell sdl2-config --cflags)
-CPPFLAGS += -I. -I$(OUTDIR) -Iimgui -Iglm \
+CPPFLAGS += -I. -I$(OUTDIR) \
+	    -Iimgui -Iglm -Ipicojson \
 	    -DREAL_BUILD -DGLM_ENABLE_EXPERIMENTAL
 LIBS += $(shell sdl2-config --libs) -lGL -lGLEW -ldl
 

externals.hh

@@ -31,6 +31,9 @@
 #include <glm/mat3x3.hpp>
 #include <glm/gtx/euler_angles.hpp>
 
+// PicoJSON
+#include <picojson.h>
+
 // Silly decoration macros I use everywhere
 #define __rd__
 #define __wr__

picojson

@@ -0,0 +1 @@
+Subproject commit 1ebfc7b998fed25c48b4c14c0907bda74ead42c5

utilities.cc

@@ -39,3 +39,93 @@ void anglesToMatrix(
 	matrix[7] = s[0]*c[1];
 	matrix[8] = c[0]*c[1];
 }
+
+
+/*= JSON =====================================================================*/
+
+template void jsonAdd< double >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ double const& v );
+template void jsonAdd< picojson::value::object >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ picojson::value::object const& v );
+template void jsonAdd< picojson::value::array >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ picojson::value::array const& v );
+template void jsonAdd< std::string >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ std::string const& v );
+
+template< >
+void jsonAdd< picojson::value >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ picojson::value const& v )
+{
+	using T_Entry = std::pair< std::string , picojson::value >;
+	object.insert( T_Entry( key , v ) );
+}
+
+template< >
+void jsonAdd< int >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ int const& v )
+{
+	using T_Entry = std::pair< std::string , picojson::value >;
+	object.insert( T_Entry( key , picojson::value( double( v ) ) ) );
+}
+
+template< >
+void jsonAdd< unsigned >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ unsigned const& v )
+{
+	using T_Entry = std::pair< std::string , picojson::value >;
+	object.insert( T_Entry( key , picojson::value( double( v ) ) ) );
+}
+
+/*----------------------------------------------------------------------------*/
+
+picojson::value jsonVector( float const* vector , const int nComponents )
+{
+	using namespace picojson;
+	value::array a;
+	for ( auto i = 0 ; i < nComponents ; i ++ ) {
+		a.push_back( value( vector[ i ] ) );
+	}
+	return value( a );
+}
+
+/*----------------------------------------------------------------------------*/
+
+void jsonGetVectorOpt(
+		__wr__ float* vector ,
+		__rd__ const size_t size ,
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* key )
+{
+	using namespace picojson;
+	auto const* ptr( jsonGetOpt< array >( object , key ) );
+	if ( !ptr ) {
+		return;
+	}
+
+	auto const& a( *ptr );
+	if ( a.size( ) != size ) {
+		throw X_JsonGetFailed( );
+	}
+
+	int i = 0;
+	for ( auto const& av : a ) {
+		if ( !av.is< double >( ) ) {
+			throw X_JsonGetFailed( );
+		}
+		vector[ i ++ ] = float( av.get< double >( ) );
+	}
+}

utilities.hh

@@ -58,3 +58,178 @@ inline auto find(
 {
 	return std::find( collection.begin( ) , collection.end( ) , item );
 }
+
+
+/*= JSON utilities ===========================================================*/
+
+// Convert a vector to a JSON array
+picojson::value jsonVector(
+		__rd__ float const* vector ,
+		__rd__ const int nComponents );
+
+// Convert a GLM vec3 to a JSON array
+inline picojson::value jsonVector(
+		__rd__ glm::vec3 const& vector )
+{
+	return jsonVector( &vector.x , 3 );
+}
+
+// Add an entry to a JSON object
+template< typename T >
+inline void jsonAdd(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ T const& v )
+{
+	using T_Entry = std::pair< std::string , picojson::value >;
+	object.insert( T_Entry( key , picojson::value( v ) ) );
+}
+
+extern template void jsonAdd< double >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ double const& v );
+extern template void jsonAdd< picojson::value::object >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ picojson::value::object const& v );
+extern template void jsonAdd< picojson::value::array >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ picojson::value::array const& v );
+extern template void jsonAdd< std::string >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ std::string const& v );
+
+template< >
+void jsonAdd< picojson::value >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ picojson::value const& v );
+template< >
+void jsonAdd< int >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ int const& v );
+template< >
+void jsonAdd< unsigned >(
+		__rw__ picojson::value::object& object ,
+		__rd__ std::string const& key ,
+		__rd__ unsigned const& v );
+
+/*----------------------------------------------------------------------------*/
+
+// JSON read type error
+class X_JsonGetFailed : public std::exception { };
+
+// Get a pointer to a JSON object field, or nullptr if the field doesn't exist.
+// Throws X_JsonGetFailed if the type is incorrect.
+template< typename T >
+inline T const* jsonGetOpt(
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* const key )
+{
+	const std::string k( key );
+	if ( object.find( k ) == object.end( ) ) {
+		return nullptr;
+	}
+
+	picojson::value const& v( object.at( k ) );
+	if ( !v.is< T >( ) ) {
+		throw X_JsonGetFailed( );
+	}
+	return &v.get< T >( );
+}
+
+// Read a value from a JSON object, if the value actually exists. Fails with
+// X_JsonGetFailed if the type is wrong
+template< typename T >
+inline bool jsonSetFromOpt(
+		__wr__ T& out ,
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* const key )
+{
+	T const* ptr( jsonGetOpt< T >( object , key ) );
+	if ( ptr ) {
+		out = *ptr;
+	}
+	return ptr;
+}
+
+// Integer specialization of the above
+template< >
+inline bool jsonSetFromOpt< int >(
+		__wr__ int& out ,
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* const key )
+{
+	double const* ptr( jsonGetOpt< double >( object , key ) );
+	if ( ptr ) {
+		out = int( *ptr );
+	}
+	return ptr;
+}
+
+// Unsigned integer specialization of the above
+template< >
+inline bool jsonSetFromOpt< unsigned >(
+		__wr__ unsigned& out ,
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* const key )
+{
+	double const* ptr( jsonGetOpt< double >( object , key ) );
+	if ( ptr ) {
+		out = unsigned( *ptr );
+	}
+	return ptr;
+}
+
+// 32-bit float specialization of the above
+template< >
+inline bool jsonSetFromOpt< float >(
+		__wr__ float& out ,
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* const key )
+{
+	double const* ptr( jsonGetOpt< double >( object , key ) );
+	if ( ptr ) {
+		out = float( *ptr );
+	}
+	return ptr;
+}
+
+// Read a vector from a JSON array of numbers
+void jsonGetVectorOpt(
+		__wr__ float* vector ,
+		__rd__ const size_t size ,
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* key );
+
+// Read a GLM vec3 from a JSON array of numbers
+inline void jsonGetVectorOpt(
+		__wr__ glm::vec3& vector ,
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* key )
+{
+	jsonGetVectorOpt( &vector.x , 3 , object , key );
+}
+
+// Try to load some object using its "bool load( jsonobject )" method.
+template< typename T >
+inline bool jsonLoadOpt(
+		__rw__ T& out ,
+		__rd__ picojson::value::object const& object ,
+		__rd__ char const* key )
+{
+	using T_Obj = picojson::value::object;
+	try {
+		auto const* sub( jsonGetOpt< T_Obj >( object , key ) );
+		if ( sub ) {
+			return out.load( *sub );
+		}
+		return true;
+	} catch ( X_JsonGetFailed const& ) {
+		return false;
+	}
+}