assimp.assimp/code/BlenderDNA.h

/*
Open Asset Import Library (assimp)
----------------------------------------------------------------------

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All rights reserved.

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  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
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  derived from this software without specific prior
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*/

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

#include "BaseImporter.h"
#include "TinyFormatter.h"

// enable verbose log output. really verbose, so be careful.
#ifdef _DEBUG
#	define ASSIMP_BUILD_BLENDER_DEBUG
#endif

// #define ASSIMP_BUILD_BLENDER_NO_STATS

namespace Assimp	{
	template <bool,bool> class StreamReader;
	typedef StreamReader<true,true> StreamReaderAny;

	namespace Blender {
		class  FileDatabase;
		struct FileBlockHead;

		template <template <typename> class TOUT>
		class ObjectCache;

// -------------------------------------------------------------------------------
/** Exception class used by the blender loader to selectively catch exceptions
 *  thrown in its own code (DeadlyImportErrors thrown in general utility
 *  functions are untouched then). If such an exception is not caught by
 *  the loader itself, it will still be caught by Assimp due to its
 *  ancestry. */
// -------------------------------------------------------------------------------
struct Error : DeadlyImportError
{
	Error (const std::string& s)
		: DeadlyImportError(s)
	{}
};

// -------------------------------------------------------------------------------
/** The only purpose of this structure is to feed a virtual dtor into its
 *  descendents. It serves as base class for all data structure fields. */
// -------------------------------------------------------------------------------
struct ElemBase 
{
	virtual ~ElemBase() {}

	/** Type name of the element. The type 
	 * string points is the `c_str` of the `name` attribute of the 
	 * corresponding `Structure`, that is, it is only valid as long 
	 * as the DNA is not modified. The dna_type is only set if the
	 * data type is not static, i.e. a boost::shared_ptr<ElemBase>
	 * in the scene description would have its type resolved 
	 * at runtime, so this member is always set. */
	const char* dna_type;
};


// -------------------------------------------------------------------------------
/** Represents a generic pointer to a memory location, which can be either 32
 *  or 64 bits. These pointers are loaded from the BLEND file and finally
 *  fixed to point to the real, converted representation of the objects 
 *  they used to point to.*/
// -------------------------------------------------------------------------------
struct Pointer
{
	Pointer() : val() {}
	uint64_t val;
};

// -------------------------------------------------------------------------------
/** Represents a generic offset within a BLEND file */
// -------------------------------------------------------------------------------
struct FileOffset
{
	FileOffset() : val() {}
	uint64_t val;
};

// -------------------------------------------------------------------------------
/** Dummy derivate of std::vector to be able to use it in templates simultaenously
 *  with boost::shared_ptr, which takes only one template argument 
 *  while std::vector takes three. Also we need to provide some special member
 *  functions of shared_ptr */
// -------------------------------------------------------------------------------
template <typename T>
class vector : public std::vector<T>
{
public:
	using std::vector<T>::resize;
	using std::vector<T>::empty;

	void reset() {
		resize(0);
	}

	operator bool () const {
		return !empty();
	}
};

// -------------------------------------------------------------------------------
/** Mixed flags for use in #Field */
// -------------------------------------------------------------------------------
enum FieldFlags 
{
	FieldFlag_Pointer = 0x1,
	FieldFlag_Array   = 0x2
};

// -------------------------------------------------------------------------------
/** Represents a single member of a data structure in a BLEND file */
// -------------------------------------------------------------------------------
struct Field 
{	
	std::string name;
	std::string type;

	size_t size;
	size_t offset;

	/** Size of each array dimension. For flat arrays,
	 *  the second dimension is set to 1. */
	size_t array_sizes[2];

	/** Any of the #FieldFlags enumerated values */
	unsigned int flags;
};

// -------------------------------------------------------------------------------
/** Range of possible behaviours for fields absend in the input file. Some are
 *  mission critical so we need them, while others can silently be default
 *  initialized and no animations are harmed. */
// -------------------------------------------------------------------------------
enum ErrorPolicy 
{
	/** Substitute default value and ignore */
	ErrorPolicy_Igno,
	/** Substitute default value and write to log */
	ErrorPolicy_Warn,
	/** Substitute a massive error message and crash the whole matrix. Its time for another zion */
	ErrorPolicy_Fail
};

#ifdef ASSIMP_BUILD_BLENDER_DEBUG
#	define ErrorPolicy_Igno ErrorPolicy_Warn
#endif

// -------------------------------------------------------------------------------
/** Represents a data structure in a BLEND file. A Structure defines n fields
 *  and their locatios and encodings the input stream. Usually, every
 *  Structure instance pertains to one equally-named data structure in the
 *  BlenderScene.h header. This class defines various utilities to map a
 *  binary `blob` read from the file to such a structure instance with
 *  meaningful contents. */
// -------------------------------------------------------------------------------
class Structure 
{
	template <template <typename> class> friend class ObjectCache;

public:

	Structure()
		:	cache_idx(-1)
	{}

public:

	// publicly accessible members
	std::string name;
	vector< Field > fields;
	std::map<std::string, size_t> indices;

	size_t size;

public:

	// --------------------------------------------------------
	/** Access a field of the structure by its canonical name. The pointer version
	 *  returns NULL on failure while the reference version raises an import error. */
	inline const Field& operator [] (const std::string& ss) const;
	inline const Field* Get (const std::string& ss) const;

	// --------------------------------------------------------
	/** Access a field of the structure by its index */
	inline const Field& operator [] (const size_t i) const;

	// --------------------------------------------------------
	inline bool operator== (const Structure& other) const {
		return name == other.name; // name is meant to be an unique identifier
	}

	// --------------------------------------------------------
	inline bool operator!= (const Structure& other) const {
		return name != other.name;
	}

public:

	// --------------------------------------------------------
	/** Try to read an instance of the structure from the stream
	 *  and attempt to convert to `T`. This is done by
	 *  an appropriate specialization. If none is available,
	 *  a compiler complain is the result.
	 *  @param dest Destination value to be written
	 *  @param db File database, including input stream. */
	template <typename T> inline void Convert (T& dest,
		const FileDatabase& db) const;



	// --------------------------------------------------------
	// generic converter
	template <typename T>
	void Convert(boost::shared_ptr<ElemBase> in,const FileDatabase& db) const;

	// --------------------------------------------------------
	// generic allocator
	template <typename T> boost::shared_ptr<ElemBase> Allocate() const;



	// --------------------------------------------------------
	// field parsing for 1d arrays
	template <int error_policy, typename T, size_t M>
	void ReadFieldArray(T (& out)[M], const char* name, 
		const FileDatabase& db) const;

	// --------------------------------------------------------
	// field parsing for 2d arrays
	template <int error_policy, typename T, size_t M, size_t N>
	void ReadFieldArray2(T (& out)[M][N], const char* name,
		const FileDatabase& db) const;

	// --------------------------------------------------------
	// field parsing for pointer or dynamic array types 
	// (boost::shared_ptr or boost::shared_array)
	template <int error_policy, template <typename> class TOUT, typename T>
	void ReadFieldPtr(TOUT<T>& out, const char* name, 
		const FileDatabase& db) const;

	// --------------------------------------------------------
	// field parsing for static arrays of pointer or dynamic
	// array types (boost::shared_ptr[] or boost::shared_array[])
	template <int error_policy, template <typename> class TOUT, typename T, size_t N>
	void ReadFieldPtr(TOUT<T> (&out)[N], const char* name, 
		const FileDatabase& db) const;

	// --------------------------------------------------------
	// field parsing for `normal` values
	template <int error_policy, typename T>
	void ReadField(T& out, const char* name, 
		const FileDatabase& db) const;

private:

	// --------------------------------------------------------
	template <template <typename> class TOUT, typename T>
	void ResolvePointer(TOUT<T>& out, const Pointer & ptrval, 
		const FileDatabase& db, const Field& f) const;

	// --------------------------------------------------------
	template <template <typename> class TOUT, typename T>
	void ResolvePointer(vector< TOUT<T> >& out, const Pointer & ptrval, 
		const FileDatabase& db, const Field& f) const;

	// --------------------------------------------------------
	void ResolvePointer( boost::shared_ptr< FileOffset >& out, const Pointer & ptrval, 
		const FileDatabase& db, const Field& f) const;

	// --------------------------------------------------------
	inline const FileBlockHead* LocateFileBlockForAddress(
		const Pointer & ptrval,
		const FileDatabase& db) const;

private:

	// ------------------------------------------------------------------------------
	template <typename T> T* _allocate(boost::shared_ptr<T>& out, size_t& s) const {
		out = boost::shared_ptr<T>(new T());
		s = 1;
		return out.get();
	}

	template <typename T> T* _allocate(vector<T>& out, size_t& s) const {
		out.resize(s);
		return s ? &out.front() : NULL;
	}

	// --------------------------------------------------------
	template <int error_policy>
	struct _defaultInitializer {

		template <typename T, unsigned int N>
		void operator ()(T (& out)[N], const char* = NULL) {
			for (unsigned int i = 0; i < N; ++i) {
				out[i] = T(); 
			}
		}

		template <typename T, unsigned int N, unsigned int M>
		void operator ()(T (& out)[N][M], const char* = NULL) {
			for (unsigned int i = 0; i < N; ++i) {
				for (unsigned int j = 0; j < M; ++j) {
					out[i][j] = T(); 
				}
			}
		}

		template <typename T>
		void operator ()(T& out, const char* = NULL) {
			out = T();
		}
	};

private:

	mutable size_t cache_idx;
};

// --------------------------------------------------------
template <>  struct Structure :: _defaultInitializer<ErrorPolicy_Warn> {

	template <typename T>
	void operator ()(T& out, const char* reason = "<add reason>") {
		DefaultLogger::get()->warn(reason);

		// ... and let the show go on
		_defaultInitializer<0 /*ErrorPolicy_Igno*/>()(out);
	}
};

template <> struct Structure :: _defaultInitializer<ErrorPolicy_Fail> {

	template <typename T>
	void operator ()(T& /*out*/,const char* = "") {
		// obviously, it is crucial that _DefaultInitializer is used 
		// only from within a catch clause.
		throw;
	}
};

// -------------------------------------------------------------------------------------------------------
template <> inline void Structure :: ResolvePointer<boost::shared_ptr,ElemBase>(boost::shared_ptr<ElemBase>& out, 
	const Pointer & ptrval, 
	const FileDatabase& db, 
	const Field& f
	) const;


// -------------------------------------------------------------------------------
/** Represents the full data structure information for a single BLEND file.
 *  This data is extracted from the DNA1 chunk in the file.
 *  #DNAParser does the reading and represents currently the only place where 
 *  DNA is altered.*/
// -------------------------------------------------------------------------------
class DNA
{
public:

	typedef void (Structure::*ConvertProcPtr) (
		boost::shared_ptr<ElemBase> in, 
		const FileDatabase&
	) const;

	typedef boost::shared_ptr<ElemBase> (
		Structure::*AllocProcPtr) () const;
	
	typedef std::pair< AllocProcPtr, ConvertProcPtr > FactoryPair;

public:

	std::map<std::string, FactoryPair > converters;
	vector<Structure > structures;
	std::map<std::string, size_t> indices;

public:

	// --------------------------------------------------------
	/** Access a structure by its canonical name, the pointer version returns NULL on failure 
	  * while the reference version raises an error. */
	inline const Structure& operator [] (const std::string& ss) const;
	inline const Structure* Get (const std::string& ss) const;

	// --------------------------------------------------------
	/** Access a structure by its index */
	inline const Structure& operator [] (const size_t i) const;

public:

	// --------------------------------------------------------
	/** Add structure definitions for all the primitive types,
	 *  i.e. integer, short, char, float */
	void AddPrimitiveStructures();

	// --------------------------------------------------------
	/** Fill the @c converters member with converters for all 
	 *  known data types. The implementation of this method is
	 *  in BlenderScene.cpp and is machine-generated.
	 *  Converters are used to quickly handle objects whose
	 *  exact data type is a runtime-property and not yet 
	 *  known at compile time (consier Object::data).*/
	void RegisterConverters();


	// --------------------------------------------------------
	/** Take an input blob from the stream, interpret it according to 
	 *  a its structure name and convert it to the intermediate
	 *  representation. 
	 *  @param structure Destination structure definition
	 *  @param db File database.
	 *  @return A null pointer if no appropriate converter is available.*/
	boost::shared_ptr< ElemBase > ConvertBlobToStructure(
		const Structure& structure,
		const FileDatabase& db
		) const;

	// --------------------------------------------------------
	/** Find a suitable conversion function for a given Structure.
	 *  Such a converter function takes a blob from the input 
	 *  stream, reads as much as it needs, and builds up a
	 *  complete object in intermediate representation.
	 *  @param structure Destination structure definition
	 *  @param db File database.
	 *  @return A null pointer in .first if no appropriate converter is available.*/
	FactoryPair GetBlobToStructureConverter(
		const Structure& structure,
		const FileDatabase& db
		) const;


#ifdef ASSIMP_BUILD_BLENDER_DEBUG
	// --------------------------------------------------------
	/** Dump the DNA to a text file. This is for debugging purposes. 
	 *  The output file is `dna.txt` in the current working folder*/
	void DumpToFile();
#endif

	// --------------------------------------------------------
	/** Extract array dimensions from a C array declaration, such
	 *  as `...[4][6]`. Returned string would be `...[][]`.
	 *  @param out
	 *  @param array_sizes Receive maximally two array dimensions,
	 *    the second element is set to 1 if the array is flat.
	 *    Both are set to 1 if the input is not an array.
	 *  @throw DeadlyImportError if more than 2 dimensions are
	 *    encountered. */
	static void ExtractArraySize(
		const std::string& out, 
		size_t array_sizes[2]
	);
};

// special converters for primitive types
template <> inline void Structure :: Convert<int>		(int& dest,const FileDatabase& db) const;
template <> inline void Structure :: Convert<short>		(short& dest,const FileDatabase& db) const;
template <> inline void Structure :: Convert<char>		(char& dest,const FileDatabase& db) const;
template <> inline void Structure :: Convert<float>		(float& dest,const FileDatabase& db) const;
template <> inline void Structure :: Convert<double>	(double& dest,const FileDatabase& db) const;
template <> inline void Structure :: Convert<Pointer>	(Pointer& dest,const FileDatabase& db) const;

// -------------------------------------------------------------------------------
/** Describes a master file block header. Each master file sections holds n
 *  elements of a certain SDNA structure (or otherwise unspecified data). */
// -------------------------------------------------------------------------------
struct FileBlockHead 
{
	// points right after the header of the file block
	StreamReaderAny::pos start;

	std::string id;
	size_t size;

	// original memory address of the data
	Pointer address;

	// index into DNA
	unsigned int dna_index;

	// number of structure instances to follow
	size_t num;



	// file blocks are sorted by address to quickly locate specific memory addresses
	bool operator < (const FileBlockHead& o) const {
		return address.val < o.address.val;
	}

	// for std::upper_bound
	operator const Pointer& () const {
		return address;
	}
};

// for std::upper_bound
inline bool operator< (const Pointer& a, const Pointer& b) {
	return a.val < b.val;
}

// -------------------------------------------------------------------------------
/** Utility to read all master file blocks in turn. */
// -------------------------------------------------------------------------------
class SectionParser 
{
public:

	// --------------------------------------------------------
	/** @param stream Inout stream, must point to the 
	 *  first section in the file. Call Next() once
	 *  to have it read. 
	 *  @param ptr64 Pointer size in file is 64 bits? */
	SectionParser(StreamReaderAny& stream,bool ptr64)
		: stream(stream)
		, ptr64(ptr64)
	{
		current.size = current.start = 0;
	}

public:

	// --------------------------------------------------------
	const FileBlockHead& GetCurrent() const {
		return current;
	}
	

public:

	// --------------------------------------------------------
	/** Advance to the next section. 
	 *  @throw DeadlyImportError if the last chunk was passed. */
	void Next();

public:

	FileBlockHead current;
	StreamReaderAny& stream;
	bool ptr64;
};


#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
// -------------------------------------------------------------------------------
/** Import statistics, i.e. number of file blocks read*/
// -------------------------------------------------------------------------------
class Statistics {

public:

	Statistics () 
		: fields_read		()
		, pointers_resolved	()
		, cache_hits		()
//		, blocks_read		()
		, cached_objects	()
	{}

public:

	/** total number of fields we read */
	unsigned int fields_read;

	/** total number of resolved pointers */
	unsigned int pointers_resolved;

	/** number of pointers resolved from the cache */
	unsigned int cache_hits;

	/** number of blocks (from  FileDatabase::entries) 
	  we did actually read from. */
	// unsigned int blocks_read;

	/** objects in FileData::cache */
	unsigned int cached_objects;
};
#endif

// -------------------------------------------------------------------------------
/** The object cache - all objects addressed by pointers are added here. This
 *  avoids circular references and avoids object duplication. */
// -------------------------------------------------------------------------------
template <template <typename> class TOUT>
class ObjectCache 
{
public:

	typedef std::map< Pointer, TOUT<ElemBase> > StructureCache;

public:

	ObjectCache(const FileDatabase& db)
		: db(db)
	{
		// currently there are only ~400 structure records per blend file.
		// we read only a small part of them and don't cache objects
		// which we don't need, so this should suffice.
		caches.reserve(64);
	}

public:

	// --------------------------------------------------------
	/** Check whether a specific item is in the cache.
	 *  @param s Data type of the item
	 *  @param out Output pointer. Unchanged if the
	 *   cache doens't know the item yet.
	 *  @param ptr Item address to look for. */
	template <typename T> void get (
		const Structure& s, 
		TOUT<T>& out, 
		const Pointer& ptr) const;

	// --------------------------------------------------------
	/** Add an item to the cache after the item has 
	 * been fully read. Do not insert anything that
	 * may be faulty or might cause the loading
	 * to abort. 
	 *  @param s Data type of the item
	 *  @param out Item to insert into the cache
	 *  @param ptr address (cache key) of the item. */
	template <typename T> void set 
		(const Structure& s, 
		const TOUT<T>& out, 
		const Pointer& ptr);

private:

	mutable vector<StructureCache> caches;
	const FileDatabase& db;
};

// -------------------------------------------------------------------------------
// -------------------------------------------------------------------------------
template <> class ObjectCache<Blender::vector> 
{
public:

	ObjectCache(const FileDatabase&) {}

	template <typename T> void get(const Structure&, vector<T>&, const Pointer&) {}
	template <typename T> void set(const Structure&, const vector<T>&, const Pointer&) {}
};

#ifdef _MSC_VER
#	pragma warning(disable:4355)
#endif

// -------------------------------------------------------------------------------
/** Memory representation of a full BLEND file and all its dependencies. The
 *  output aiScene is constructed from an instance of this data structure. */
// -------------------------------------------------------------------------------
class FileDatabase 
{
	template <template <typename> class TOUT> friend class ObjectCache;

public:


	FileDatabase()
		: _cacheArrays(*this)
		, _cache(*this)
		, next_cache_idx()
	{} 

public:

	// publicly accessible fields
	bool i64bit;
	bool little;

	DNA dna;
	boost::shared_ptr< StreamReaderAny > reader;
	vector< FileBlockHead > entries;

public:

	Statistics& stats() const {
		return _stats;
	}

	// For all our templates to work on both shared_ptr's and vector's
	// using the same code, a dummy cache for arrays is provided. Actually,
	// arrays of objects are never cached because we can't easily 
	// ensure their proper destruction.
	template <typename T>
	ObjectCache<boost::shared_ptr>& cache(boost::shared_ptr<T>& /*in*/) const {
		return _cache;
	}

	template <typename T>
	ObjectCache<vector>& cache(vector<T>& /*in*/) const {
		return _cacheArrays;
	}

private:

	
#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
	mutable Statistics _stats;
#endif

	mutable ObjectCache<vector> _cacheArrays;
	mutable ObjectCache<boost::shared_ptr> _cache;

	mutable size_t next_cache_idx;
};

#ifdef _MSC_VER
#	pragma warning(default:4355)
#endif

// -------------------------------------------------------------------------------
/** Factory to extract a #DNA from the DNA1 file block in a BLEND file. */
// -------------------------------------------------------------------------------
class DNAParser 
{

public:

	/** Bind the parser to a empty DNA and an input stream */
	DNAParser(FileDatabase& db)
		: db(db)
	{}

public:

	// --------------------------------------------------------
	/** Locate the DNA in the file and parse it. The input
	 *  stream is expected to point to the beginning of the DN1
	 *  chunk at the time this method is called and is
	 *  undefined afterwards.
	 *  @throw DeadlyImportError if the DNA cannot be read.
	 *  @note The position of the stream pointer is undefined
	 *    afterwards.*/
	void Parse ();

public:

	/** Obtain a reference to the extracted DNA information */
	const Blender::DNA& GetDNA() const {
		return db.dna;
	}

private:

	FileDatabase& db;
};

	} // end Blend
} // end Assimp

#include "BlenderDNA.inl"

#endif