assimp/code/BlenderDNA.inl

/*
Open Asset Import Library (ASSIMP)
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*/

/** @file  BlenderDNA.inl
 *  @brief Blender `DNA` (file format specification embedded in 
 *    blend file itself) loader.
 */
#ifndef INCLUDED_AI_BLEND_DNA_INL
#define INCLUDED_AI_BLEND_DNA_INL

namespace Assimp	{
	namespace Blender {

//--------------------------------------------------------------------------------
const Field& Structure :: operator [] (const std::string& ss) const
{
	std::map<std::string, size_t>::const_iterator it = indices.find(ss);
	if (it == indices.end()) {
		throw Error((Formatter::format(),
			"BlendDNA: Did not find a field named `",ss,"` in structure `",name,"`"
			));
	}

	return fields[(*it).second];
}

//--------------------------------------------------------------------------------
const Field& Structure :: operator [] (const size_t i) const 
{
	if (i >= fields.size()) {
		throw Error((Formatter::format(),
			"BlendDNA: There is no field with index `",i,"` in structure `",name,"`"
			));
	}

	return fields[i];
}

//--------------------------------------------------------------------------------
template <typename T> boost::shared_ptr<ElemBase> Structure :: Convert(
	const FileDatabase& db) const 
{
	// FIXME: use boost::make_shared
	boost::shared_ptr<T> s = boost::shared_ptr<T>(new T()); 
	Convert<T> (*s.get(),db);

	return s;
}

//--------------------------------------------------------------------------------
template <int error_policy, typename T, size_t M>
void Structure :: ReadFieldArray(T (& out)[M], const char* name, const FileDatabase& db) const
{
	const StreamReaderAny::pos old = db.reader->GetCurrentPos();
	try {
		const Field& f = (*this)[name];
		const Structure& s = db.dna[f.type];

		// is the input actually an array?
		if (!(f.flags & FieldFlag_Array)) {
			throw Error((Formatter::format(),"Field `",name,"` of structure `",
				this->name,"` ought to be an array of size ",M
				));
		}

		db.reader->IncPtr(f.offset);

		// size conversions are always allowed, regardless of error_policy
		unsigned int i = 0;
		for(; i < std::min(f.array_sizes[0],M); ++i) {
			s.Convert(out[i],db);
		}
		for(; i < M; ++i) {
			_defaultInitializer<ErrorPolicy_Igno>()(out[i]);
		}
	}
	catch (const Error& e) {
		_defaultInitializer<error_policy>()(out,e.what());
	}

	// and recover the previous stream position
	db.reader->SetCurrentPos(old);

#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
	++db.stats().fields_read;
#endif
}

//--------------------------------------------------------------------------------
template <int error_policy, typename T, size_t M, size_t N>
void Structure :: ReadFieldArray2(T (& out)[M][N], const char* name, const FileDatabase& db) const
{
	const StreamReaderAny::pos old = db.reader->GetCurrentPos();
	try {
		const Field& f = (*this)[name];
		const Structure& s = db.dna[f.type];

		// is the input actually an array?
		if (!(f.flags & FieldFlag_Array)) {
			throw Error((Formatter::format(),"Field `",name,"` of structure `",
				this->name,"` ought to be an array of size ",M,"*",N
				));
		}

		db.reader->IncPtr(f.offset);

		// size conversions are always allowed, regardless of error_policy
		unsigned int i = 0;
		for(; i < std::min(f.array_sizes[0],M); ++i) {
			unsigned int j = 0;
			for(; j < std::min(f.array_sizes[1],N); ++j) {
				s.Convert(out[i][j],db);
			}
			for(; j < N; ++j) {
				_defaultInitializer<ErrorPolicy_Igno>()(out[i][j]);
			}
		}
		for(; i < M; ++i) {
			_defaultInitializer<ErrorPolicy_Igno>()(out[i]);
		}
	}
	catch (const Error& e) {
		_defaultInitializer<error_policy>()(out,e.what());
	}

	// and recover the previous stream position
	db.reader->SetCurrentPos(old);

#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
	++db.stats().fields_read;
#endif
}

//--------------------------------------------------------------------------------
template <int error_policy, template <typename> class TOUT, typename T>
void Structure :: ReadFieldPtr(TOUT<T>& out, const char* name, const FileDatabase& db) const
{
	const StreamReaderAny::pos old = db.reader->GetCurrentPos();
	Pointer ptrval;
	const Field* f;
	try {
		f = &(*this)[name];

		// sanity check, should never happen if the genblenddna script is right
		if (!(f->flags & FieldFlag_Pointer)) {
			throw Error((Formatter::format(),"Field `",name,"` of structure `",
				this->name,"` ought to be a pointer"
				));
		}

		db.reader->IncPtr(f->offset);
		Convert(ptrval,db);
		// actually it is meaningless on which Structure the Convert is called
		// because the `Pointer` argument triggers a special implementation.
	}
	catch (const Error& e) {
		_defaultInitializer<error_policy>()(out,e.what());

		out.reset();
		return;
	}

	// resolve the pointer and load the corresponding structure
	ResolvePointer(out,ptrval,db,*f);

	// and recover the previous stream position
	db.reader->SetCurrentPos(old);

#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
	if (out) {
		++db.stats().pointers_resolved;
	}
	++db.stats().fields_read;
#endif
}

//--------------------------------------------------------------------------------
template <int error_policy, typename T>
void Structure :: ReadField(T& out, const char* name, const FileDatabase& db) const
{
	const StreamReaderAny::pos old = db.reader->GetCurrentPos();
	try {
		const Field& f = (*this)[name];
		// find the structure definition pertaining to this field
		const Structure& s = db.dna[f.type];

		db.reader->IncPtr(f.offset);
		s.Convert(out,db);
	}
	catch (const Error& e) {
		_defaultInitializer<error_policy>()(out,e.what());
	}

	// and recover the previous stream position
	db.reader->SetCurrentPos(old);

#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
	++db.stats().fields_read;
#endif
}


//--------------------------------------------------------------------------------
template <template <typename> class TOUT, typename T>
void Structure :: ResolvePointer(TOUT<T>& out, const Pointer & ptrval, const FileDatabase& db, const Field& f) const 
{
	out.reset();
	if (ptrval.val) { 
		const Structure& s = db.dna[f.type];

		// find the file block the pointer is pointing to
		const FileBlockHead* block = LocateFileBlockForAddress(ptrval,db);

		// also determine the target type from the block header
		// and check if it matches the type which we expect.
		const Structure& ss = db.dna[block->dna_index];
		if (ss != s) {
			throw Error((Formatter::format(),"Expected target to be of type `",s.name,
				"` but seemingly it is a `",ss.name,"` instead"
			));
		}

		// try to retrieve the object from the cache
		db.cache(out).get(s,out,ptrval); 
		if (out) {
			return;
		}

		// seek to this location, but save the previous stream pointer.
		const StreamReaderAny::pos pold = db.reader->GetCurrentPos();
		db.reader->SetCurrentPos(block->start+ static_cast<size_t>((ptrval.val - block->address.val) ));
		// FIXME: basically, this could cause problems with 64 bit pointers on 32 bit systems.
		// I really ought to improve StreamReader to work with 64 bit indices exclusively.

		// continue conversion after allocating the required storage
		size_t num = block->size / ss.size; 
		_allocate(out,num);

		// cache the object before we convert it to avoid
		// cyclic recursion.
		db.cache(out).set(s,out,ptrval); 

		T* o = out.get();
		for (size_t i = 0; i < num; ++i,++o) {
			s.Convert(*o,db);
		}

		db.reader->SetCurrentPos(pold);
	}
}

//--------------------------------------------------------------------------------
template <> void Structure :: ResolvePointer<boost::shared_ptr,ElemBase>(boost::shared_ptr<ElemBase>& out, 
	const Pointer & ptrval, 
	const FileDatabase& db, 
	const Field& f
) const 
{
	// Special case when the data type needs to be determined at runtime.
	// Less secure than in the `strongly-typed` case.

	out.reset();
	if (ptrval.val) { 
		// find the file block the pointer is pointing to
		const FileBlockHead* block = LocateFileBlockForAddress(ptrval,db);

		// determine the target type from the block header
		const Structure& s = db.dna[block->dna_index];

		// try to retrieve the object from the cache
		db.cache(out).get(s,out,ptrval); 
		if (out) {
			return;
		}

		// seek to this location, but save the previous stream pointer.
		const StreamReaderAny::pos pold = db.reader->GetCurrentPos();
		db.reader->SetCurrentPos(block->start+ static_cast<size_t>((ptrval.val - block->address.val) ));
		// FIXME: basically, this could cause problems with 64 bit pointers on 32 bit systems.
		// I really ought to improve StreamReader to work with 64 bit indices exclusively.

		// continue conversion after allocating the required storage
		out = db.dna.ConvertBlobToStructure(s,db);
		db.reader->SetCurrentPos(pold);
		if (!out) {
			// this might happen if DNA::RegisterConverters hasn't been called so far
			// or if the target type is not contained in `our` DNA.
			out.reset();
			DefaultLogger::get()->warn((Formatter::format(),
				"Failed to find a converter for the `",s.name,"` structure"
			));
			return;
		}

		// store a pointer to the name string of the actual type
		// in the object itself. This allows the conversion code
		// to perform additional type checking.
		out->dna_type = s.name.c_str();

		// cache the object now that construction is complete
		// FIXME we need to do this in ConvertBlobToStructure
		db.cache(out).set(s,out,ptrval);
	}
}

//--------------------------------------------------------------------------------
const FileBlockHead* Structure :: LocateFileBlockForAddress(const Pointer & ptrval, const FileDatabase& db) const 
{
	// the file blocks appear in list sorted by
	// with ascending base addresses so we can run a 
	// binary search to locate the pointee quickly.

	// NOTE: Blender seems to distinguish between side-by-side
	// data (stored in the same data block) and far pointers,
	// which are only used for structures starting with an ID.
	// We don't need to make this distinction, our algorithm
	// works regardless where the data is stored.
	std::vector<FileBlockHead>::const_iterator it = std::lower_bound(db.entries.begin(),db.entries.end(),ptrval);
	if (it == db.entries.end()) {
		// this is crucial, pointers may not be invalid.
		// this is either a corrupted file or an attempted attack.
		throw DeadlyImportError((Formatter::format(),"Failure resolving pointer 0x",
			std::hex,ptrval.val,", no file block falls into this address range"
			));
	}
	if (ptrval.val >= (*it).address.val + (*it).size) {
		throw DeadlyImportError((Formatter::format(),"Failure resolving pointer 0x",
			std::hex,ptrval.val,", nearest file block starting at 0x",
			(*it).address.val," ends at 0x",
			(*it).address.val + (*it).size
			));
	}
	return &*it;
}

// ------------------------------------------------------------------------------------------------
// NOTE: The MSVC debugger keeps showing up this annoying `a cast to a smaller data type has 
// caused a loss of data`-warning. Avoid this warning by a masking with an appropriate bitmask.

template <typename T> struct signless;
template <> struct signless<char> {typedef unsigned char type;};
template <> struct signless<short> {typedef unsigned short type;};
template <> struct signless<int> {typedef unsigned int type;};

template <typename T>
struct static_cast_silent {	
	template <typename V>
	T operator()(V in) {
		return static_cast<T>(in & static_cast<typename signless<T>::type>(-1));
	}
};

template <> struct static_cast_silent<float> {
	template <typename V> float  operator()(V in) {
		return static_cast<float> (in);
	}
};

template <> struct static_cast_silent<double> {
	template <typename V> double operator()(V in) {
		return static_cast<double>(in);
	}
};

// ------------------------------------------------------------------------------------------------
template <typename T> inline void ConvertDispatcher(T& out, const Structure& in,const FileDatabase& db) 
{
	if (in.name == "int") {
		out = static_cast_silent<T>()(db.reader->GetU4());
		//db.reader->IncPtr(-4);
	}
	else if (in.name == "short") {
		out = static_cast_silent<T>()(db.reader->GetU2());
		//db.reader->IncPtr(-2);
	}
	else if (in.name == "char") {
		out = static_cast_silent<T>()(db.reader->GetU1());
		//db.reader->IncPtr(-1);
	}
	else if (in.name == "float") {
		out = static_cast<T>(db.reader->GetF4());
		//db.reader->IncPtr(-4);
	}
	else if (in.name == "double") {
		out = static_cast<T>(db.reader->GetF8());
		//db.reader->IncPtr(-8);
	}
	else {
		throw DeadlyImportError("Unknown source for conversion to primitive data type: "+in.name);
	}
}

// ------------------------------------------------------------------------------------------------
template <> inline void Structure :: Convert<int>    (int& dest,const FileDatabase& db) const
{
	ConvertDispatcher(dest,*this,db);
}

// ------------------------------------------------------------------------------------------------
template <> inline void Structure :: Convert<short>  (short& dest,const FileDatabase& db) const
{
	ConvertDispatcher(dest,*this,db);
}

// ------------------------------------------------------------------------------------------------
template <> inline void Structure :: Convert<char>   (char& dest,const FileDatabase& db) const
{
	// automatic rescaling from char to float and vice versa (seems useful for RGB colors)
	if (name == "float") {
		dest = static_cast<char>(db.reader->GetF4() * 255.f);
		//db.reader->IncPtr(-4);
		return;
	}
	else if (name == "double") {
		dest = static_cast<char>(db.reader->GetF8() * 255.f);
		//db.reader->IncPtr(-8);
		return;
	}
	ConvertDispatcher(dest,*this,db);
}

// ------------------------------------------------------------------------------------------------
template <> inline void Structure :: Convert<float>  (float& dest,const FileDatabase& db) const
{
	// automatic rescaling from char to float and vice versa (seems useful for RGB colors)
	if (name == "char") {
		dest = db.reader->GetI1() / 255.f;
		//db.reader->IncPtr(-1);
		return;
	}
	ConvertDispatcher(dest,*this,db);
}

// ------------------------------------------------------------------------------------------------
template <> inline void Structure :: Convert<double> (double& dest,const FileDatabase& db) const
{
	if (name == "char") {
		dest = db.reader->GetI1() / 255.f;
		//db.reader->IncPtr(-1);
		return;
	}
	ConvertDispatcher(dest,*this,db);
}

// ------------------------------------------------------------------------------------------------
template <> inline void Structure :: Convert<Pointer> (Pointer& dest,const FileDatabase& db) const
{
	if (db.i64bit) {
		dest.val = db.reader->GetU8();
		//db.reader->IncPtr(-8);
		return;
	}
	dest.val = db.reader->GetU4();
	//db.reader->IncPtr(-4);
}

//--------------------------------------------------------------------------------
const Structure& DNA :: operator [] (const std::string& ss) const
{
	std::map<std::string, size_t>::const_iterator it = indices.find(ss);
	if (it == indices.end()) {
		throw Error((Formatter::format(),
			"BlendDNA: Did not find a structure named `",ss,"`"
			));
	}

	return structures[(*it).second];
}

//--------------------------------------------------------------------------------
const Structure& DNA :: operator [] (const size_t i) const 
{
	if (i >= structures.size()) {
		throw Error((Formatter::format(),
			"BlendDNA: There is no structure with index `",i,"`"
			));
	}

	return structures[i];
}

//--------------------------------------------------------------------------------
template <template <typename> class TOUT> template <typename T> void ObjectCache<TOUT> :: get (
	const Structure& s, 
	TOUT<T>& out, 
	const Pointer& ptr
) const {

	if(s.cache_idx == static_cast<size_t>(-1)) {
		s.cache_idx = db.next_cache_idx++;
		caches.resize(db.next_cache_idx);
		return;
	}

	typename StructureCache::const_iterator it = caches[s.cache_idx].find(ptr);
	if (it != caches[s.cache_idx].end()) {
		out = boost::static_pointer_cast<T>( (*it).second );

#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
		++db.stats().cache_hits;
#endif
	}
	// otherwise, out remains untouched
}


//--------------------------------------------------------------------------------
template <template <typename> class TOUT> template <typename T> void ObjectCache<TOUT> :: set (
	const Structure& s, 
	const TOUT<T>& out,
	const Pointer& ptr
) {
	if(s.cache_idx == static_cast<size_t>(-1)) {
		s.cache_idx = db.next_cache_idx++;
		caches.resize(db.next_cache_idx);
	}
	caches[s.cache_idx][ptr] = boost::static_pointer_cast<ElemBase>( out ); 

#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
	++db.stats().cached_objects;
#endif
}

}}
#endif