btSerializer.h

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/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2009 Erwin Coumans  http://bulletphysics.org

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#ifndef BT_SERIALIZER_H
#define BT_SERIALIZER_H

#include "btScalar.h" // has definitions like SIMD_FORCE_INLINE
#include "btStackAlloc.h"
#include "btHashMap.h"

#if !defined( __CELLOS_LV2__) && !defined(__MWERKS__)
#include <memory.h>
#endif
#include <string.h>



extern unsigned char sBulletDNAstr[];
extern int sBulletDNAlen;
extern unsigned char sBulletDNAstr64[];
extern int sBulletDNAlen64;

SIMD_FORCE_INLINE       int btStrLen(const char* str) 
{
    if (!str) 
                return(0);
        int len = 0;
    
        while (*str != 0)
        {
        str++;
        len++;
    }

    return len;
}


class btChunk
{
public:
        int             m_chunkCode;
        int             m_length;
        void    *m_oldPtr;
        int             m_dna_nr;
        int             m_number;
};

class   btSerializer
{

public:

        virtual ~btSerializer() {}

        virtual const unsigned char*            getBufferPointer() const = 0;

        virtual int             getCurrentBufferSize() const = 0;

        virtual btChunk*        allocate(size_t size, int numElements) = 0;

        virtual void    finalizeChunk(btChunk* chunk, const char* structType, int chunkCode,void* oldPtr)= 0;

        virtual  void*  findPointer(void* oldPtr)  = 0;

        virtual void    startSerialization() = 0;
        
        virtual void    finishSerialization() = 0;

        virtual const char*     findNameForPointer(const void* ptr) const = 0;

        virtual void    registerNameForPointer(const void* ptr, const char* name) = 0;

        virtual void    serializeName(const char* ptr) = 0;

};



#define BT_HEADER_LENGTH 12
#if defined(__sgi) || defined (__sparc) || defined (__sparc__) || defined (__PPC__) || defined (__ppc__) || defined (__BIG_ENDIAN__)
#       define MAKE_ID(a,b,c,d) ( (int)(a)<<24 | (int)(b)<<16 | (c)<<8 | (d) )
#else
#       define MAKE_ID(a,b,c,d) ( (int)(d)<<24 | (int)(c)<<16 | (b)<<8 | (a) )
#endif

#define BT_COLLISIONOBJECT_CODE MAKE_ID('C','O','B','J')
#define BT_RIGIDBODY_CODE               MAKE_ID('R','B','D','Y')
#define BT_CONSTRAINT_CODE              MAKE_ID('C','O','N','S')
#define BT_BOXSHAPE_CODE                MAKE_ID('B','O','X','S')
#define BT_SHAPE_CODE                   MAKE_ID('S','H','A','P')
#define BT_ARRAY_CODE                   MAKE_ID('A','R','A','Y')



class btDefaultSerializer       :       public btSerializer
{


        btAlignedObjectArray<char*>                     mTypes;
        btAlignedObjectArray<short*>                    mStructs;
        btAlignedObjectArray<short>                     mTlens;
        btHashMap<btHashInt, int>                       mStructReverse;
        btHashMap<btHashString,int>     mTypeLookup;

        
        btHashMap<btHashPtr,void*>      m_chunkP;
        
        btHashMap<btHashPtr,const char*>        m_nameMap;


        int                                     m_totalSize;
        unsigned char*          m_buffer;
        int                                     m_currentSize;
        void*                           m_dna;
        int                                     m_dnaLength;


        btAlignedObjectArray<btChunk*>  m_chunkPtrs;
        
protected:

        virtual void*   findPointer(void* oldPtr) 
        {
                void** ptr = m_chunkP.find(oldPtr);
                if (ptr && *ptr)
                        return *ptr;
                return 0;
        }



                void    writeDNA()
                {
                        unsigned char* dnaTarget = m_buffer+m_currentSize;
                        memcpy(dnaTarget,m_dna,m_dnaLength);
                        m_currentSize += m_dnaLength;
                }

                int getReverseType(const char *type) const
                {

                        btHashString key(type);
                        const int* valuePtr = mTypeLookup.find(key);
                        if (valuePtr)
                                return *valuePtr;
                        
                        return -1;
                }

                void initDNA(const char* bdnaOrg,int dnalen)
                {
                        if (m_dna)
                                return;

                        int littleEndian= 1;
                        littleEndian= ((char*)&littleEndian)[0];
                        

                        m_dna = btAlignedAlloc(dnalen,16);
                        memcpy(m_dna,bdnaOrg,dnalen);
                        m_dnaLength = dnalen;

                        int *intPtr=0;
                        short *shtPtr=0;
                        char *cp = 0;int dataLen =0;long nr=0;
                        intPtr = (int*)m_dna;

                        /*
                                SDNA (4 bytes) (magic number)
                                NAME (4 bytes)
                                <nr> (4 bytes) amount of names (int)
                                <string>
                                <string>
                        */

                        if (strncmp((const char*)m_dna, "SDNA", 4)==0)
                        {
                                // skip ++ NAME
                                intPtr++; intPtr++;
                        }

                        // Parse names
                        if (!littleEndian)
                                *intPtr = btSwapEndian(*intPtr);
                                
                        dataLen = *intPtr;
                        
                        intPtr++;

                        cp = (char*)intPtr;
                        int i;
                        for ( i=0; i<dataLen; i++)
                        {
                                
                                while (*cp)cp++;
                                cp++;
                        }
                        {
                                nr= (long)cp;
                        //      long mask=3;
                                nr= ((nr+3)&~3)-nr;
                                while (nr--)
                                {
                                        cp++;
                                }
                        }

                        /*
                                TYPE (4 bytes)
                                <nr> amount of types (int)
                                <string>
                                <string>
                        */

                        intPtr = (int*)cp;
                        assert(strncmp(cp, "TYPE", 4)==0); intPtr++;

                        if (!littleEndian)
                                *intPtr =  btSwapEndian(*intPtr);
                        
                        dataLen = *intPtr;
                        intPtr++;

                        
                        cp = (char*)intPtr;
                        for (i=0; i<dataLen; i++)
                        {
                                mTypes.push_back(cp);
                                while (*cp)cp++;
                                cp++;
                        }

                {
                                nr= (long)cp;
                        //      long mask=3;
                                nr= ((nr+3)&~3)-nr;
                                while (nr--)
                                {
                                        cp++;
                                }
                        }


                        /*
                                TLEN (4 bytes)
                                <len> (short) the lengths of types
                                <len>
                        */

                        // Parse type lens
                        intPtr = (int*)cp;
                        assert(strncmp(cp, "TLEN", 4)==0); intPtr++;

                        dataLen = (int)mTypes.size();

                        shtPtr = (short*)intPtr;
                        for (i=0; i<dataLen; i++, shtPtr++)
                        {
                                if (!littleEndian)
                                        shtPtr[0] = btSwapEndian(shtPtr[0]);
                                mTlens.push_back(shtPtr[0]);
                        }

                        if (dataLen & 1) shtPtr++;

                        /*
                                STRC (4 bytes)
                                <nr> amount of structs (int)
                                <typenr>
                                <nr_of_elems>
                                <typenr>
                                <namenr>
                                <typenr>
                                <namenr>
                        */

                        intPtr = (int*)shtPtr;
                        cp = (char*)intPtr;
                        assert(strncmp(cp, "STRC", 4)==0); intPtr++;

                        if (!littleEndian)
                                *intPtr = btSwapEndian(*intPtr);
                        dataLen = *intPtr ; 
                        intPtr++;


                        shtPtr = (short*)intPtr;
                        for (i=0; i<dataLen; i++)
                        {
                                mStructs.push_back (shtPtr);
                                
                                if (!littleEndian)
                                {
                                        shtPtr[0]= btSwapEndian(shtPtr[0]);
                                        shtPtr[1]= btSwapEndian(shtPtr[1]);

                                        int len = shtPtr[1];
                                        shtPtr+= 2;

                                        for (int a=0; a<len; a++, shtPtr+=2)
                                        {
                                                        shtPtr[0]= btSwapEndian(shtPtr[0]);
                                                        shtPtr[1]= btSwapEndian(shtPtr[1]);
                                        }

                                } else
                                {
                                        shtPtr+= (2*shtPtr[1])+2;
                                }
                        }

                        // build reverse lookups
                        for (i=0; i<(int)mStructs.size(); i++)
                        {
                                short *strc = mStructs.at(i);
                                mStructReverse.insert(strc[0], i);
                                mTypeLookup.insert(btHashString(mTypes[strc[0]]),i);
                        }
                }

public: 
        

        

                btDefaultSerializer(int totalSize)
                        :m_totalSize(totalSize),
                        m_currentSize(0),
                        m_dna(0),
                        m_dnaLength(0)
                {
                        m_buffer = (unsigned char*)btAlignedAlloc(totalSize, 16);
                        
                        const bool VOID_IS_8 = ((sizeof(void*)==8));

#ifdef BT_INTERNAL_UPDATE_SERIALIZATION_STRUCTURES
                        if (VOID_IS_8)
                        {
#if _WIN64
                                initDNA((const char*)sBulletDNAstr64,sBulletDNAlen64);
#else
                                btAssert(0);
#endif
                        } else
                        {
#ifndef _WIN64
                                initDNA((const char*)sBulletDNAstr,sBulletDNAlen);
#else
                                btAssert(0);
#endif
                        }
        
#else //BT_INTERNAL_UPDATE_SERIALIZATION_STRUCTURES
                        if (VOID_IS_8)
                        {
                                initDNA((const char*)sBulletDNAstr64,sBulletDNAlen64);
                        } else
                        {
                                initDNA((const char*)sBulletDNAstr,sBulletDNAlen);
                        }
#endif //BT_INTERNAL_UPDATE_SERIALIZATION_STRUCTURES
        
                }

                virtual ~btDefaultSerializer() 
                {
                        if (m_buffer)
                                btAlignedFree(m_buffer);
                        if (m_dna)
                                btAlignedFree(m_dna);
                }

                virtual void    startSerialization()
                {
                        m_currentSize = BT_HEADER_LENGTH;

#ifdef  BT_USE_DOUBLE_PRECISION
                        memcpy(m_buffer, "BULLETd", 7);
#else
                        memcpy(m_buffer, "BULLETf", 7);
#endif //BT_USE_DOUBLE_PRECISION
        
                        int littleEndian= 1;
                        littleEndian= ((char*)&littleEndian)[0];

                        if (sizeof(void*)==8)
                        {
                                m_buffer[7] = '-';
                        } else
                        {
                                m_buffer[7] = '_';
                        }

                        if (littleEndian)
                        {
                                m_buffer[8]='v';                                
                        } else
                        {
                                m_buffer[8]='V';
                        }


                        m_buffer[9] = '2';
                        m_buffer[10] = '7';
                        m_buffer[11] = '6';

                        
                }

                virtual void    finishSerialization()
                {
                        writeDNA();
                }


                virtual const unsigned char*            getBufferPointer() const
                {
                        return m_buffer;
                }

                virtual int                                     getCurrentBufferSize() const
                {
                        return  m_currentSize;
                }

                virtual void    finalizeChunk(btChunk* chunk, const char* structType, int chunkCode,void* oldPtr)
                {
                        btAssert(!findPointer(oldPtr));

                        chunk->m_dna_nr = getReverseType(structType);
                        
                        chunk->m_chunkCode = chunkCode;
                        m_chunkP.insert(oldPtr,chunk->m_oldPtr);
                        chunk->m_oldPtr = oldPtr;
                        
                }

                

                

                virtual btChunk*        allocate(size_t size, int numElements)
                {

                        unsigned char* ptr = m_buffer+m_currentSize;
                        m_currentSize += int(size)*numElements+sizeof(btChunk);
                        btAssert(m_currentSize<m_totalSize);

                        unsigned char* data = ptr + sizeof(btChunk);
                        
                        btChunk* chunk = (btChunk*)ptr;
                        chunk->m_chunkCode = 0;
                        chunk->m_oldPtr = data;
                        chunk->m_length = int(size)*numElements;
                        chunk->m_number = numElements;
                        
                        m_chunkPtrs.push_back(chunk);
                        

                        return chunk;
                }

                virtual const char*     findNameForPointer(const void* ptr) const
                {
                        const char*const * namePtr = m_nameMap.find(ptr);
                        if (namePtr && *namePtr)
                                return *namePtr;
                        return 0;

                }

                virtual void    registerNameForPointer(const void* ptr, const char* name)
                {
                        m_nameMap.insert(ptr,name);
                }

                virtual void    serializeName(const char* name)
                {
                        if (name)
                        {
                                int len = btStrLen(name);
                                if (len)
                                {

                                        int newLen = len+1;
                                        int padding = ((newLen+3)&~3)-newLen;
                                        newLen += padding;

                                        //serialize name string now
                                        btChunk* chunk = allocate(sizeof(char),newLen);
                                        char* destinationName = (char*)chunk->m_oldPtr;
                                        for (int i=0;i<len;i++)
                                        {
                                                destinationName[i] = name[i];
                                        }
                                        destinationName[len] = 0;
                                        finalizeChunk(chunk,"char",BT_ARRAY_CODE,(void*)name);
                                }
                        }
                }
};


#endif //BT_SERIALIZER_H