/*

---------------------------------------------------------------------------

Open Asset Import Library (assimp)

---------------------------------------------------------------------------

Copyright (c) 2006-2026, assimp team

All rights reserved.

Redistribution and use of this software in source and binary forms,

with or without modification, are permitted provided that the following

conditions are met:

* Redistributions of source code must retain the above

  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

  materials provided with the distribution.

* Neither the name of the assimp team, nor the names of its

  contributors may be used to endorse or promote products

  derived from this software without specific prior

  written permission of the assimp team.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

---------------------------------------------------------------------------

*/

/** @file  Importer.cpp

 *  @brief Implementation of the CPP-API class #Importer

 */

#include <assimp/version.h>

#include <assimp/config.h>

#include <assimp/importerdesc.h>

// ------------------------------------------------------------------------------------------------

/* Uncomment this line to prevent Assimp from catching unknown exceptions.

 *

 * Note that any Exception except DeadlyImportError may lead to

 * undefined behaviour -> loaders could remain in an unusable state and

 * further imports with the same Importer instance could fail/crash/burn ...

 */

// ------------------------------------------------------------------------------------------------

#ifndef ASSIMP_BUILD_DEBUG

#   define ASSIMP_CATCH_GLOBAL_EXCEPTIONS

#endif

// ------------------------------------------------------------------------------------------------

// Internal headers

// ------------------------------------------------------------------------------------------------

#include "Common/Importer.h"

#include "Common/BaseProcess.h"

#include "Common/DefaultProgressHandler.h"

#include "PostProcessing/ProcessHelper.h"

#include "Common/ScenePreprocessor.h"

#include "Common/ScenePrivate.h"

#include <assimp/BaseImporter.h>

#include <assimp/GenericProperty.h>

#include <assimp/MemoryIOWrapper.h>

#include <assimp/Profiler.h>

#include <assimp/TinyFormatter.h>

#include <assimp/Exceptional.h>

#include <assimp/Profiler.h>

#include <assimp/commonMetaData.h>

#include <exception>

#include <set>

#include <memory>

#include <cctype>

#include <assimp/DefaultIOStream.h>

#include <assimp/DefaultIOSystem.h>

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

#   include "PostProcessing/ValidateDataStructure.h"

#endif

using namespace Assimp::Profiling;

using namespace Assimp::Formatter;

namespace Assimp {

    // ImporterRegistry.cpp

    void GetImporterInstanceList(std::vector< BaseImporter* >& out);

  void DeleteImporterInstanceList(std::vector< BaseImporter* >& out);

    // PostStepRegistry.cpp

    void GetPostProcessingStepInstanceList(std::vector< BaseProcess* >& out);

}

using namespace Assimp;

using namespace Assimp::Intern;

// ------------------------------------------------------------------------------------------------

// Intern::AllocateFromAssimpHeap serves as abstract base class. It overrides

// new and delete (and their array counterparts) of public API classes (e.g. Logger) to

// utilize our DLL heap.

// See http://www.gotw.ca/publications/mill15.htm

// ------------------------------------------------------------------------------------------------

void* AllocateFromAssimpHeap::operator new ( size_t num_bytes)  {

    return ::operator new(num_bytes);

}

void* AllocateFromAssimpHeap::operator new ( size_t num_bytes, const std::nothrow_t& ) throw()  {

    try {

        return AllocateFromAssimpHeap::operator new( num_bytes );

    }

    catch( ... )    {

        return nullptr;

    }

}

void AllocateFromAssimpHeap::operator delete ( void* data)  {

    return ::operator delete(data);

}

void* AllocateFromAssimpHeap::operator new[] ( size_t num_bytes)    {

    return ::operator new[](num_bytes);

}

void* AllocateFromAssimpHeap::operator new[] ( size_t num_bytes, const std::nothrow_t& ) throw() {

    try {

        return AllocateFromAssimpHeap::operator new[]( num_bytes );

    } catch( ... )    {

        return nullptr;

    }

}

void AllocateFromAssimpHeap::operator delete[] ( void* data)    {

    return ::operator delete[](data);

}

// ------------------------------------------------------------------------------------------------

// Importer constructor.

Importer::Importer()

 : pimpl( new ImporterPimpl ) {

    pimpl->mScene = nullptr;

    pimpl->mErrorString = std::string();

    // Allocate a default IO handler

    pimpl->mIOHandler = new DefaultIOSystem;

    pimpl->mIsDefaultHandler = true;

    pimpl->bExtraVerbose     = false; // disable extra verbose mode by default

    pimpl->mProgressHandler = new DefaultProgressHandler();

    pimpl->mIsDefaultProgressHandler = true;

    GetImporterInstanceList(pimpl->mImporter);

    GetPostProcessingStepInstanceList(pimpl->mPostProcessingSteps);

    // Allocate a SharedPostProcessInfo object and store pointers to it in all post-process steps in the list.

    pimpl->mPPShared = new SharedPostProcessInfo();

    for (std::vector<BaseProcess*>::iterator it =  pimpl->mPostProcessingSteps.begin();

        it != pimpl->mPostProcessingSteps.end();

        ++it)   {

        (*it)->SetSharedData(pimpl->mPPShared);

    }

}

// ------------------------------------------------------------------------------------------------

// Destructor of Importer

Importer::~Importer() {

    // Delete all import plugins

  DeleteImporterInstanceList(pimpl->mImporter);

    // Delete all post-processing plug-ins

    for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); ++a ) {

        delete pimpl->mPostProcessingSteps[a];

    }

    // Delete the assigned IO and progress handler

    delete pimpl->mIOHandler;

    delete pimpl->mProgressHandler;

    // Kill imported scene. Destructor's should do that recursively

    delete pimpl->mScene;

    // Delete shared post-processing data

    delete pimpl->mPPShared;

    // and finally the pimpl itself

    delete pimpl;

}

// ------------------------------------------------------------------------------------------------

// Register a custom post-processing step

aiReturn Importer::RegisterPPStep(BaseProcess* pImp) {

    ai_assert( nullptr != pImp );

    ASSIMP_BEGIN_EXCEPTION_REGION();

        pimpl->mPostProcessingSteps.push_back(pImp);

        ASSIMP_LOG_INFO("Registering custom post-processing step");

    ASSIMP_END_EXCEPTION_REGION(aiReturn);

    return AI_SUCCESS;

}

// ------------------------------------------------------------------------------------------------

// Register a custom loader plugin

aiReturn Importer::RegisterLoader(BaseImporter* pImp) {

    ai_assert(nullptr != pImp);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    // --------------------------------------------------------------------

    // Check whether we would have two loaders for the same file extension

    // This is absolutely OK, but we should warn the developer of the new

    // loader that his code will probably never be called if the first

    // loader is a bit too lazy in his file checking.

    // --------------------------------------------------------------------

    std::set<std::string> st;

    std::string baked;

    pImp->GetExtensionList(st);

    for(std::set<std::string>::const_iterator it = st.begin(); it != st.end(); ++it) {

#ifdef ASSIMP_BUILD_DEBUG

        if (IsExtensionSupported(*it)) {

            ASSIMP_LOG_WARN("The file extension ", *it, " is already in use");

        }

#endif

        baked += *it;

    }

    // add the loader

    pimpl->mImporter.push_back(pImp);

    ASSIMP_LOG_INFO("Registering custom importer for these file extensions: ", baked);

    ASSIMP_END_EXCEPTION_REGION(aiReturn);

    return AI_SUCCESS;

}

// ------------------------------------------------------------------------------------------------

// Unregister a custom loader plugin

aiReturn Importer::UnregisterLoader(BaseImporter* pImp) {

    if(!pImp) {

        // unregistering a nullptr importer is no problem for us ... really!

        return AI_SUCCESS;

    }

    ASSIMP_BEGIN_EXCEPTION_REGION();

    std::vector<BaseImporter*>::iterator it = std::find(pimpl->mImporter.begin(),

        pimpl->mImporter.end(),pImp);

    if (it != pimpl->mImporter.end())   {

        pimpl->mImporter.erase(it);

        ASSIMP_LOG_INFO("Unregistering custom importer: ");

        return AI_SUCCESS;

    }

    ASSIMP_LOG_WARN("Unable to remove custom importer: I can't find you ...");

    ASSIMP_END_EXCEPTION_REGION(aiReturn);

    return AI_FAILURE;

}

// ------------------------------------------------------------------------------------------------

// Unregister a custom loader plugin

aiReturn Importer::UnregisterPPStep(BaseProcess* pImp) {

    if(!pImp) {

        // unregistering a nullptr ppstep is no problem for us ... really!

        return AI_SUCCESS;

    }

    ASSIMP_BEGIN_EXCEPTION_REGION();

    std::vector<BaseProcess*>::iterator it = std::find(pimpl->mPostProcessingSteps.begin(),

        pimpl->mPostProcessingSteps.end(),pImp);

    if (it != pimpl->mPostProcessingSteps.end())    {

        pimpl->mPostProcessingSteps.erase(it);

        ASSIMP_LOG_INFO("Unregistering custom post-processing step");

        return AI_SUCCESS;

    }

    ASSIMP_LOG_WARN("Unable to remove custom post-processing step: I can't find you ..");

    ASSIMP_END_EXCEPTION_REGION(aiReturn);

    return AI_FAILURE;

}

// ------------------------------------------------------------------------------------------------

// Supplies a custom IO handler to the importer to open and access files.

void Importer::SetIOHandler( IOSystem* pIOHandler) {

    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    // If the new handler is zero, allocate a default IO implementation.

    if (!pIOHandler) {

        // Release pointer in the possession of the caller

        pimpl->mIOHandler = new DefaultIOSystem();

        pimpl->mIsDefaultHandler = true;

    } else if (pimpl->mIOHandler != pIOHandler) { // Otherwise register the custom handler

        delete pimpl->mIOHandler;

        pimpl->mIOHandler = pIOHandler;

        pimpl->mIsDefaultHandler = false;

    }

    ASSIMP_END_EXCEPTION_REGION(void);

}

// ------------------------------------------------------------------------------------------------

// Get the currently set IO handler

IOSystem* Importer::GetIOHandler() const {

    ai_assert(nullptr != pimpl);

    return pimpl->mIOHandler;

}

// ------------------------------------------------------------------------------------------------

// Check whether a custom IO handler is currently set

bool Importer::IsDefaultIOHandler() const {

    ai_assert(nullptr != pimpl);

    return pimpl->mIsDefaultHandler;

}

// ------------------------------------------------------------------------------------------------

// Supplies a custom progress handler to get regular callbacks during importing

void Importer::SetProgressHandler(ProgressHandler* pHandler) {

    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    // If the new handler is zero, allocate a default implementation.

    if (!pHandler) {

        // Release pointer in the possession of the caller

        pimpl->mProgressHandler = new DefaultProgressHandler();

        pimpl->mIsDefaultProgressHandler = true;

    } else if (pimpl->mProgressHandler != pHandler) { // Otherwise register the custom handler

        delete pimpl->mProgressHandler;

        pimpl->mProgressHandler = pHandler;

        pimpl->mIsDefaultProgressHandler = false;

    }

    ASSIMP_END_EXCEPTION_REGION(void);

}

// ------------------------------------------------------------------------------------------------

// Get the currently set progress handler

ProgressHandler* Importer::GetProgressHandler() const {

    ai_assert(nullptr != pimpl);

    return pimpl->mProgressHandler;

}

// ------------------------------------------------------------------------------------------------

// Check whether a custom progress handler is currently set

bool Importer::IsDefaultProgressHandler() const {

    ai_assert(nullptr != pimpl);

    return pimpl->mIsDefaultProgressHandler;

}

// ------------------------------------------------------------------------------------------------

// Validate post process step flags

bool _ValidateFlags(unsigned int pFlags) {

    if (pFlags & aiProcess_GenSmoothNormals && pFlags & aiProcess_GenNormals)   {

        ASSIMP_LOG_ERROR("#aiProcess_GenSmoothNormals and #aiProcess_GenNormals are incompatible");

        return false;

    }

    if (pFlags & aiProcess_OptimizeGraph && pFlags & aiProcess_PreTransformVertices)    {

        ASSIMP_LOG_ERROR("#aiProcess_OptimizeGraph and #aiProcess_PreTransformVertices are incompatible");

        return false;

    }

    return true;

}

// ------------------------------------------------------------------------------------------------

// Free the current scene

void Importer::FreeScene( ) {

    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    delete pimpl->mScene;

    pimpl->mScene = nullptr;

    pimpl->mErrorString = std::string();

    pimpl->mException = std::exception_ptr();

    ASSIMP_END_EXCEPTION_REGION(void);

}

// ------------------------------------------------------------------------------------------------

// Get the current error string, if any

const char* Importer::GetErrorString() const {

    ai_assert(nullptr != pimpl);

    // Must remain valid as long as ReadFile() or FreeFile() are not called

    return pimpl->mErrorString.c_str();

}

const std::exception_ptr& Importer::GetException() const {

    ai_assert(nullptr != pimpl);

    // Must remain valid as long as ReadFile() or FreeFile() are not called

    return pimpl->mException;

}

// ------------------------------------------------------------------------------------------------

// Enable extra-verbose mode

void Importer::SetExtraVerbose(bool bDo) {

    ai_assert(nullptr != pimpl);

    pimpl->bExtraVerbose = bDo;

}

// ------------------------------------------------------------------------------------------------

// Get the current scene

const aiScene* Importer::GetScene() const {

    ai_assert(nullptr != pimpl);

    return pimpl->mScene;

}

// ------------------------------------------------------------------------------------------------

// Orphan the current scene and return it.

aiScene* Importer::GetOrphanedScene() {

    ai_assert(nullptr != pimpl);

    aiScene* s = pimpl->mScene;

    ASSIMP_BEGIN_EXCEPTION_REGION();

    pimpl->mScene = nullptr;

    pimpl->mErrorString = std::string();

    pimpl->mException = std::exception_ptr();

    ASSIMP_END_EXCEPTION_REGION(aiScene*);

    return s;

}

// ------------------------------------------------------------------------------------------------

// Validate post-processing flags

bool Importer::ValidateFlags(unsigned int pFlags) const {

    ASSIMP_BEGIN_EXCEPTION_REGION();

    // run basic checks for mutually exclusive flags

    if(!_ValidateFlags(pFlags)) {

        return false;

    }

    // ValidateDS does not anymore occur in the pp list, it plays an awesome extra role ...

#ifdef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

    if (pFlags & aiProcess_ValidateDataStructure) {

        return false;

    }

#endif

    pFlags &= ~aiProcess_ValidateDataStructure;

    // Now iterate through all bits which are set in the flags and check whether we find at least

    // one pp plugin which handles it.

    for (unsigned int mask = 1; mask < (1u << (sizeof(unsigned int)*8-1));mask <<= 1) {

        if (pFlags & mask) {

            bool have = false;

            for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++)   {

                if (pimpl->mPostProcessingSteps[a]-> IsActive(mask) ) {

                    have = true;

                    break;

                }

            }

            if (!have) {

                return false;

            }

        }

    }

    ASSIMP_END_EXCEPTION_REGION(bool);

    return true;

}

// ------------------------------------------------------------------------------------------------

const aiScene* Importer::ReadFileFromMemory(const void* pBuffer, size_t pLength, unsigned int pFlags, const char* pHint ) {

    ai_assert(nullptr != pimpl);

    IOSystem* io = pimpl->mIOHandler;

    try {

        if (pHint == nullptr) {

            pHint = "";

        }

        if (!pBuffer || !pLength || strlen(pHint) > MaxLenHint ) {

            pimpl->mErrorString = "Invalid parameters passed to ReadFileFromMemory()";

            return nullptr;

        }

        // prevent deletion of the previous IOHandler

        pimpl->mIOHandler = nullptr;

        SetIOHandler(new MemoryIOSystem((const uint8_t*)pBuffer,pLength,io));

        // read the file and recover the previous IOSystem

        static const size_t BufSize(Importer::MaxLenHint + 28);

        char fbuff[BufSize];

        ai_snprintf(fbuff, BufSize, "%s.%s",AI_MEMORYIO_MAGIC_FILENAME,pHint);

        ReadFile(fbuff,pFlags);

        SetIOHandler(io);

    } catch(const DeadlyImportError &e) {

        pimpl->mErrorString = e.what();

        pimpl->mException = std::current_exception();

        SetIOHandler(io);

        return ExceptionSwallower<const aiScene*>()();                                                                                                    \

    } catch(...) {

        pimpl->mErrorString = "Unknown exception";

        pimpl->mException = std::current_exception();

        SetIOHandler(io);

        return ExceptionSwallower<const aiScene*>()();                                                                                                    \

    }

    return pimpl->mScene;

}

// ------------------------------------------------------------------------------------------------

void WriteLogOpening(const std::string& file) {

    ASSIMP_LOG_INFO("Load ", file);

    // print a full version dump. This is nice because we don't

    // need to ask the authors of incoming bug reports for

    // the library version they're using - a log dump is

    // sufficient.

    const unsigned int flags = aiGetCompileFlags();

    std::stringstream stream;

    stream << "Assimp " << aiGetVersionMajor() << "." << aiGetVersionMinor() << "." << aiGetVersionRevision() << " "

#if defined(ASSIMP_BUILD_ARCHITECTURE)

           << ASSIMP_BUILD_ARCHITECTURE

#elif defined(_M_IX86) || defined(__x86_32__) || defined(__i386__)

           << "x86"

#elif defined(_M_X64) || defined(__x86_64__)

           << "amd64"

#elif defined(_M_IA64) || defined(__ia64__)

           << "itanium"

#elif defined(__ppc__) || defined(__powerpc__)

           << "ppc32"

#elif defined(__powerpc64__)

           << "ppc64"

#elif defined(__arm__)

           << "arm"

#else

           << "<unknown architecture>"

#endif

           << " "

#if defined(ASSIMP_BUILD_COMPILER)

           << (ASSIMP_BUILD_COMPILER)

#elif defined(_MSC_VER)

           << "msvc"

#elif defined(__GNUC__)

           << "gcc"

#elif defined(__clang__)

           << "clang"

#elif defined(__EMSCRIPTEN__)

           << "emscripten"

#elif defined(__MINGW32__)

           << "MinGW-w64 32bit"

#elif defined(__MINGW64__)

           << "MinGW-w64 64bit"

#else

           << "<unknown compiler>"

#endif

#ifdef ASSIMP_BUILD_DEBUG

           << " debug"

#endif

           << (flags & ASSIMP_CFLAGS_NOBOOST ? " noboost" : "")

           << (flags & ASSIMP_CFLAGS_SHARED ? " shared" : "")

           << (flags & ASSIMP_CFLAGS_SINGLETHREADED ? " singlethreaded" : "")

           << (flags & ASSIMP_CFLAGS_DOUBLE_SUPPORT ? " double : " : "single : ");

    ASSIMP_LOG_DEBUG(stream.str());

}

// ------------------------------------------------------------------------------------------------

// Reads the given file and returns its contents if successful.

const aiScene* Importer::ReadFile( const char* _pFile, unsigned int pFlags) {

    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    const std::string pFile(_pFile);

    // ----------------------------------------------------------------------

    // Put a large try block around everything to catch all std::exception's

    // that might be thrown by STL containers or by new().

    // ImportErrorException's are throw by ourselves and caught elsewhere.

    //-----------------------------------------------------------------------

    WriteLogOpening(pFile);

#ifdef ASSIMP_CATCH_GLOBAL_EXCEPTIONS

    try

#endif // ! ASSIMP_CATCH_GLOBAL_EXCEPTIONS

    {

        // Check whether this Importer instance has already loaded

        // a scene. In this case we need to delete the old one

        if (pimpl->mScene)  {

            ASSIMP_LOG_DEBUG("(Deleting previous scene)");

            FreeScene();

        }

        // First check if the file is accessible at all

        if( !pimpl->mIOHandler->Exists( pFile)) {

            pimpl->mErrorString = "Unable to open file \"" + pFile + "\".";

            ASSIMP_LOG_ERROR(pimpl->mErrorString);

            return nullptr;

        }

        std::unique_ptr<Profiler> profiler(GetPropertyInteger(AI_CONFIG_GLOB_MEASURE_TIME, 0) ? new Profiler() : nullptr);

        if (profiler) {

            profiler->BeginRegion("total");

        }

        // Find an worker class which can handle the file extension.

        // Multiple importers may be able to handle the same extension (.xml!); gather them all.

        SetPropertyInteger("importerIndex", -1);

        struct ImporterAndIndex {

            BaseImporter * importer;

            unsigned int   index;

        };

        std::vector<ImporterAndIndex> possibleImporters;

        for (unsigned int a = 0; a < pimpl->mImporter.size(); a++)  {

            // Every importer has a list of supported extensions.

            std::set<std::string> extensions;

            pimpl->mImporter[a]->GetExtensionList(extensions);

            if (BaseImporter::HasExtension(pFile, extensions)) {

                ImporterAndIndex candidate = { pimpl->mImporter[a], a };

                possibleImporters.push_back(candidate);

            }

        }

        // If just one importer supports this extension, pick it and close the case.

        BaseImporter* imp = nullptr;

        if (1 == possibleImporters.size()) {

            imp = possibleImporters[0].importer;

            SetPropertyInteger("importerIndex", possibleImporters[0].index);

        }

        // If multiple importers claim this file extension, ask them to look at the actual file data to decide.

        // This can happen e.g. with XML (COLLADA vs. Irrlicht).

        else {

            for (std::vector<ImporterAndIndex>::const_iterator it = possibleImporters.begin(); it < possibleImporters.end(); ++it) {

                BaseImporter & importer = *it->importer;

                ASSIMP_LOG_INFO("Found a possible importer: " + std::string(importer.GetInfo()->mName) + "; trying signature-based detection");

                if (importer.CanRead( pFile, pimpl->mIOHandler, true)) {

                    imp = &importer;

                    SetPropertyInteger("importerIndex", it->index);

                    break;

                }

            }

        }

        if (!imp)   {

            // not so bad yet ... try format auto detection.

            ASSIMP_LOG_INFO("File extension not known, trying signature-based detection");

            for( unsigned int a = 0; a < pimpl->mImporter.size(); a++)  {

                if( pimpl->mImporter[a]->CanRead( pFile, pimpl->mIOHandler, true)) {

                    imp = pimpl->mImporter[a];

                    SetPropertyInteger("importerIndex", a);

                    break;

                }

            }

            // Put a proper error message if no suitable importer was found

            if( !imp)   {

                pimpl->mErrorString = "No suitable reader found for the file format of file \"" + pFile + "\".";

                ASSIMP_LOG_ERROR(pimpl->mErrorString);

                return nullptr;

            }

        }

        // Get file size for progress handler

        IOStream * fileIO = pimpl->mIOHandler->Open( pFile );

        uint32_t fileSize = 0;

        if (fileIO)

        {

            fileSize = static_cast<uint32_t>(fileIO->FileSize());

            pimpl->mIOHandler->Close( fileIO );

        }

        // Dispatch the reading to the worker class for this format

        const aiImporterDesc *desc( imp->GetInfo() );

        std::string ext( "unknown" );

        if ( nullptr != desc ) {

            ext = desc->mName;

        }

        ASSIMP_LOG_INFO("Found a matching importer for this file format: ", ext, "." );

        pimpl->mProgressHandler->UpdateFileRead( 0, fileSize );

        if (profiler) {

            profiler->BeginRegion("import");

        }

        pimpl->mScene = imp->ReadFile( this, pFile, pimpl->mIOHandler);

        pimpl->mProgressHandler->UpdateFileRead( fileSize, fileSize );

        if (profiler) {

            profiler->EndRegion("import");

        }

        SetPropertyString("sourceFilePath", pFile);

        // If successful, apply all active post processing steps to the imported data

        if( pimpl->mScene)  {

            if (!pimpl->mScene->mMetaData || !pimpl->mScene->mMetaData->HasKey(AI_METADATA_SOURCE_FORMAT)) {

                if (!pimpl->mScene->mMetaData) {

                    pimpl->mScene->mMetaData = new aiMetadata;

                }

                pimpl->mScene->mMetaData->Add(AI_METADATA_SOURCE_FORMAT, aiString(ext));

            }

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

            // The ValidateDS process is an exception. It is executed first, even before ScenePreprocessor is called.

            if (pFlags & aiProcess_ValidateDataStructure) {

                ValidateDSProcess ds;

                ds.ExecuteOnScene (this);

                if (!pimpl->mScene) {

                    return nullptr;

                }

            }

#endif // ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

            // Preprocess the scene and prepare it for post-processing

            if (profiler) {

                profiler->BeginRegion("preprocess");

            }

            ScenePreprocessor pre(pimpl->mScene);

            pre.ProcessScene();

            if (profiler) {

                profiler->EndRegion("preprocess");

            }

            // Ensure that the validation process won't be called twice

            ApplyPostProcessing(pFlags & (~aiProcess_ValidateDataStructure));

        }

        // if failed, extract the error string

        else if( !pimpl->mScene) {

            pimpl->mErrorString = imp->GetErrorText();

            pimpl->mException = imp->GetException();

        }

        // clear any data allocated by post-process steps

        pimpl->mPPShared->Clean();

        if (profiler) {

            profiler->EndRegion("total");

        }

    }

#ifdef ASSIMP_CATCH_GLOBAL_EXCEPTIONS

    catch (std::exception &e) {

#if (defined _MSC_VER) &&   (defined _CPPRTTI)

        // if we have RTTI get the full name of the exception that occurred

        pimpl->mErrorString = std::string(typeid( e ).name()) + ": " + e.what();

#else

        pimpl->mErrorString = std::string("std::exception: ") + e.what();

#endif

        pimpl->mException = std::current_exception();

        ASSIMP_LOG_ERROR(pimpl->mErrorString);

        delete pimpl->mScene; pimpl->mScene = nullptr;

    }

#endif // ! ASSIMP_CATCH_GLOBAL_EXCEPTIONS

    // either successful or failure - the pointer expresses it anyways

    ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(const aiScene*, pimpl->mErrorString, pimpl->mException);

    return pimpl->mScene;

}

// ------------------------------------------------------------------------------------------------

// Apply post-processing to the currently bound scene

const aiScene* Importer::ApplyPostProcessing(unsigned int pFlags) {

    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    // Return immediately if no scene is active

    if (!pimpl->mScene) {

        return nullptr;

    }

    // If no flags are given, return the current scene with no further action

    if (!pFlags) {

        return pimpl->mScene;

    }

    // In debug builds: run basic flag validation

    ai_assert(_ValidateFlags(pFlags));

    ASSIMP_LOG_INFO("Entering post processing pipeline");

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

    // The ValidateDS process plays an exceptional role. It isn't contained in the global

    // list of post-processing steps, so we need to call it manually.

    if (pFlags & aiProcess_ValidateDataStructure) {

        ValidateDSProcess ds;

        ds.ExecuteOnScene (this);

        if (!pimpl->mScene) {

            return nullptr;

        }

    }

#endif // no validation

#ifdef ASSIMP_BUILD_DEBUG

    if (pimpl->bExtraVerbose)

    {

#ifdef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

        ASSIMP_LOG_ERROR("Verbose Import is not available due to build settings");

#endif  // no validation

        pFlags |= aiProcess_ValidateDataStructure;

    }

#else

    if (pimpl->bExtraVerbose) {

        ASSIMP_LOG_WARN("Not a debug build, ignoring extra verbose setting");

    }

#endif // ! DEBUG

    std::unique_ptr<Profiler> profiler(GetPropertyInteger(AI_CONFIG_GLOB_MEASURE_TIME, 0) ? new Profiler() : nullptr);

    for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++)   {

        BaseProcess* process = pimpl->mPostProcessingSteps[a];

        pimpl->mProgressHandler->UpdatePostProcess(static_cast<int>(a), static_cast<int>(pimpl->mPostProcessingSteps.size()) );

        if( process->IsActive( pFlags)) {

            if (profiler) {

                profiler->BeginRegion("postprocess");

            }

            process->ExecuteOnScene ( this );

            if (profiler) {

                profiler->EndRegion("postprocess");

            }

        }

        if( !pimpl->mScene) {

            break;

        }

#ifdef ASSIMP_BUILD_DEBUG

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

        // If the extra verbose mode is active, execute the ValidateDataStructureStep again - after each step

        if (pimpl->bExtraVerbose)   {

            ASSIMP_LOG_DEBUG("Verbose Import: re-validating data structures");

            ValidateDSProcess ds;

            ds.ExecuteOnScene (this);

            if( !pimpl->mScene) {

                ASSIMP_LOG_ERROR("Verbose Import: failed to re-validate data structures");

                break;

            }

        }

#endif  // no validation

#endif // ! DEBUG

    }

    pimpl->mProgressHandler->UpdatePostProcess( static_cast<int>(pimpl->mPostProcessingSteps.size()),

        static_cast<int>(pimpl->mPostProcessingSteps.size()) );

    // update private scene flags

    if( pimpl->mScene ) {

      ScenePriv(pimpl->mScene)->mPPStepsApplied |= pFlags;

    }

    // clear any data allocated by post-process steps

    pimpl->mPPShared->Clean();

    ASSIMP_LOG_INFO("Leaving post processing pipeline");

    ASSIMP_END_EXCEPTION_REGION(const aiScene*);

    return pimpl->mScene;

}

// ------------------------------------------------------------------------------------------------

const aiScene* Importer::ApplyCustomizedPostProcessing( BaseProcess *rootProcess, bool requestValidation ) {

    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    // Return immediately if no scene is active

    if ( nullptr == pimpl->mScene ) {

        return nullptr;

    }

    // If no flags are given, return the current scene with no further action

    if (nullptr == rootProcess) {

        return pimpl->mScene;

    }

    // In debug builds: run basic flag validation

    ASSIMP_LOG_INFO( "Entering customized post processing pipeline" );

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

    // The ValidateDS process plays an exceptional role. It isn't contained in the global

    // list of post-processing steps, so we need to call it manually.

    if ( requestValidation )

    {

        ValidateDSProcess ds;

        ds.ExecuteOnScene( this );

        if ( !pimpl->mScene ) {

            return nullptr;

        }

    }

#endif // no validation

#ifdef ASSIMP_BUILD_DEBUG

    if ( pimpl->bExtraVerbose )

    {

#ifdef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

        ASSIMP_LOG_ERROR( "Verbose Import is not available due to build settings" );

#endif  // no validation

    }

#else

    if ( pimpl->bExtraVerbose ) {

        ASSIMP_LOG_WARN( "Not a debug build, ignoring extra verbose setting" );

    }

#endif // ! DEBUG

    std::unique_ptr<Profiler> profiler(GetPropertyInteger(AI_CONFIG_GLOB_MEASURE_TIME, 0) ? new Profiler() : nullptr);

    if ( profiler ) {

        profiler->BeginRegion( "postprocess" );

    }

    rootProcess->ExecuteOnScene( this );

    if ( profiler ) {

        profiler->EndRegion( "postprocess" );

    }

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS

    // If the extra verbose mode is active, execute the ValidateDataStructureStep again - after each step

    if ( pimpl->bExtraVerbose || requestValidation  ) {

        ASSIMP_LOG_DEBUG( "Verbose Import: revalidating data structures" );

        ValidateDSProcess ds;

        ds.ExecuteOnScene( this );

        if ( !pimpl->mScene ) {

            ASSIMP_LOG_ERROR( "Verbose Import: failed to revalidate data structures" );

        }

    }

#endif // no validation

    // clear any data allocated by post-process steps

    pimpl->mPPShared->Clean();

    ASSIMP_LOG_INFO( "Leaving customized post processing pipeline" );

    ASSIMP_END_EXCEPTION_REGION( const aiScene* );

    return pimpl->mScene;

}

// ------------------------------------------------------------------------------------------------

// Helper function to check whether an extension is supported by ASSIMP

bool Importer::IsExtensionSupported(const char* szExtension) const {

    return nullptr != GetImporter(szExtension);

}

// ------------------------------------------------------------------------------------------------

size_t Importer::GetImporterCount() const {

    ai_assert(nullptr != pimpl);

    return pimpl->mImporter.size();

}

// ------------------------------------------------------------------------------------------------

const aiImporterDesc* Importer::GetImporterInfo(size_t index) const {

    ai_assert(nullptr != pimpl);

    if (index >= pimpl->mImporter.size()) {

        return nullptr;

    }

    return pimpl->mImporter[index]->GetInfo();

}

// ------------------------------------------------------------------------------------------------