text: /*
  ---------------------------------------------------------------------------
  Open Asset Import Library (assimp)
  ---------------------------------------------------------------------------
  
  Copyright (c) 2006-2021, 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  BaseImporter.cpp
   *  @brief Implementation of BaseImporter
   */
  
  #include "FileSystemFilter.h"
  #include "Importer.h"
  #include <assimp/BaseImporter.h>
  #include <assimp/ByteSwapper.h>
  #include <assimp/ParsingUtils.h>
  #include <assimp/importerdesc.h>
  #include <assimp/postprocess.h>
  #include <assimp/scene.h>
  #include <assimp/Importer.hpp>
  
  #include <cctype>
  #include <ios>
  #include <list>
  #include <memory>
  #include <sstream>
  
  using namespace Assimp;
  
  // ------------------------------------------------------------------------------------------------
  // Constructor to be privately used by Importer
  BaseImporter::BaseImporter() AI_NO_EXCEPT
          : m_progress() {
      // empty
  }
  
  // ------------------------------------------------------------------------------------------------
  // Destructor, private as well
  BaseImporter::~BaseImporter() {
      // nothing to do here
  }
  
  void BaseImporter::UpdateImporterScale(Importer *pImp) {
      ai_assert(pImp != nullptr);
      ai_assert(importerScale != 0.0);
      ai_assert(fileScale != 0.0);
  
      double activeScale = importerScale * fileScale;
  
      // Set active scaling
      pImp->SetPropertyFloat(AI_CONFIG_APP_SCALE_KEY, static_cast<float>(activeScale));
  
      ASSIMP_LOG_DEBUG("UpdateImporterScale scale set: ", activeScale);
  }
  
  // ------------------------------------------------------------------------------------------------
  // Imports the given file and returns the imported data.
  aiScene *BaseImporter::ReadFile(Importer *pImp, const std::string &pFile, IOSystem *pIOHandler) {
  
      m_progress = pImp->GetProgressHandler();
      if (nullptr == m_progress) {
          return nullptr;
      }
  
      ai_assert(m_progress);
  
      // Gather configuration properties for this run
      SetupProperties(pImp);
  
      // Construct a file system filter to improve our success ratio at reading external files
      FileSystemFilter filter(pFile, pIOHandler);
  
      // create a scene object to hold the data
      std::unique_ptr<aiScene> sc(new aiScene());
  
      // dispatch importing
      try {
          InternReadFile(pFile, sc.get(), &filter);
  
          // Calculate import scale hook - required because pImp not available anywhere else
          // passes scale into ScaleProcess
          UpdateImporterScale(pImp);
  
      } catch( const std::exception &err ) {
          // extract error description
          m_ErrorText = err.what();
          ASSIMP_LOG_ERROR(err.what());
          m_Exception = std::current_exception();
          return nullptr;
      }
  
      // return what we gathered from the import.
      return sc.release();
  }
  
  // ------------------------------------------------------------------------------------------------
  void BaseImporter::SetupProperties(const Importer *) {
      // the default implementation does nothing
  }
  
  // ------------------------------------------------------------------------------------------------
  void BaseImporter::GetExtensionList(std::set<std::string> &extensions) {
      const aiImporterDesc *desc = GetInfo();
      ai_assert(desc != nullptr);
  
      const char *ext = desc->mFileExtensions;
      ai_assert(ext != nullptr);
  
      const char *last = ext;
      do {
          if (!*ext || *ext == ' ') {
              extensions.insert(std::string(last, ext - last));
              ai_assert(ext - last > 0);
              last = ext;
              while (*last == ' ') {
                  ++last;
              }
          }
      } while (*ext++);
  }
  
  // ------------------------------------------------------------------------------------------------
  /*static*/ bool BaseImporter::SearchFileHeaderForToken(IOSystem *pIOHandler,
          const std::string &pFile,
          const char * const *tokens,
          unsigned int numTokens,
          unsigned int searchBytes /* = 200 */,
          bool tokensSol /* false */,
          bool noAlphaBeforeTokens /* false */) {
      ai_assert(nullptr != tokens);
      ai_assert(0 != numTokens);
      ai_assert(0 != searchBytes);
  
      if (nullptr == pIOHandler) {
          return false;
      }
  
      std::unique_ptr<IOStream> pStream(pIOHandler->Open(pFile));
      if (pStream) {
          // read 200 characters from the file
          std::unique_ptr<char[]> _buffer(new char[searchBytes + 1 /* for the '\0' */]);
          char *buffer(_buffer.get());
          const size_t read(pStream->Read(buffer, 1, searchBytes));
          if (0 == read) {
              return false;
          }
  
          for (size_t i = 0; i < read; ++i) {
              buffer[i] = static_cast<char>(::tolower((unsigned char)buffer[i]));
          }
  
          // It is not a proper handling of unicode files here ...
          // ehm ... but it works in most cases.
          char *cur = buffer, *cur2 = buffer, *end = &buffer[read];
          while (cur != end) {
              if (*cur) {
                  *cur2++ = *cur;
              }
              ++cur;
          }
          *cur2 = '\0';
  
          std::string token;
          for (unsigned int i = 0; i < numTokens; ++i) {
              ai_assert(nullptr != tokens[i]);
              const size_t len(strlen(tokens[i]));
              token.clear();
              const char *ptr(tokens[i]);
              for (size_t tokIdx = 0; tokIdx < len; ++tokIdx) {
                  token.push_back(static_cast<char>(tolower(static_cast<unsigned char>(*ptr))));
                  ++ptr;
              }
              const char *r = strstr(buffer, token.c_str());
              if (!r) {
                  continue;
              }
              // We need to make sure that we didn't accidentally identify the end of another token as our token,
              // e.g. in a previous version the "gltf " present in some gltf files was detected as "f "
              if (noAlphaBeforeTokens && (r != buffer && isalpha(static_cast<unsigned char>(r[-1])))) {
                  continue;
              }
              // We got a match, either we don't care where it is, or it happens to
              // be in the beginning of the file / line
              if (!tokensSol || r == buffer || r[-1] == '\r' || r[-1] == '\n') {
                  ASSIMP_LOG_DEBUG("Found positive match for header keyword: ", tokens[i]);
                  return true;
              }
          }
      }
  
      return false;
  }
  
  // ------------------------------------------------------------------------------------------------
  // Simple check for file extension
  /*static*/ bool BaseImporter::SimpleExtensionCheck(const std::string &pFile,
          const char *ext0,
          const char *ext1,
          const char *ext2) {
      std::string::size_type pos = pFile.find_last_of('.');
  
      // no file extension - can't read
      if (pos == std::string::npos)
          return false;
  
      const char *ext_real = &pFile[pos + 1];
      if (!ASSIMP_stricmp(ext_real, ext0))
          return true;
  
      // check for other, optional, file extensions
      if (ext1 && !ASSIMP_stricmp(ext_real, ext1))
          return true;
  
      if (ext2 && !ASSIMP_stricmp(ext_real, ext2))
          return true;
  
      return false;
  }
  
  // ------------------------------------------------------------------------------------------------
  // Get file extension from path
  std::string BaseImporter::GetExtension(const std::string &file) {
      std::string::size_type pos = file.find_last_of('.');
  
      // no file extension at all
      if (pos == std::string::npos) {
          return std::string();
      }
  
      // thanks to Andy Maloney for the hint
      std::string ret = file.substr(pos + 1);
      ret = ai_tolower(ret);
  
      return ret;
  }
  
  // ------------------------------------------------------------------------------------------------
  // Check for magic bytes at the beginning of the file.
  /* static */ bool BaseImporter::CheckMagicToken(IOSystem *pIOHandler, const std::string &pFile,
          const void *_magic, unsigned int num, unsigned int offset, unsigned int size) {
      ai_assert(size <= 16);
      ai_assert(_magic);
  
      if (!pIOHandler) {
          return false;
      }
      union {
          const char *magic;
          const uint16_t *magic_u16;
          const uint32_t *magic_u32;
      };
      magic = reinterpret_cast<const char *>(_magic);
      std::unique_ptr<IOStream> pStream(pIOHandler->Open(pFile));
      if (pStream) {
  
          // skip to offset
          pStream->Seek(offset, aiOrigin_SET);
  
          // read 'size' characters from the file
          union {
              char data[16];
              uint16_t data_u16[8];
              uint32_t data_u32[4];
          };
          if (size != pStream->Read(data, 1, size)) {
              return false;
          }
  
          for (unsigned int i = 0; i < num; ++i) {
              // also check against big endian versions of tokens with size 2,4
              // that's just for convenience, the chance that we cause conflicts
              // is quite low and it can save some lines and prevent nasty bugs
              if (2 == size) {
                  uint16_t rev = *magic_u16;
                  ByteSwap::Swap(&rev);
                  if (data_u16[0] == *magic_u16 || data_u16[0] == rev) {
                      return true;
                  }
              } else if (4 == size) {
                  uint32_t rev = *magic_u32;
                  ByteSwap::Swap(&rev);
                  if (data_u32[0] == *magic_u32 || data_u32[0] == rev) {
                      return true;
                  }
              } else {
                  // any length ... just compare
                  if (!memcmp(magic, data, size)) {
                      return true;
                  }
              }
              magic += size;
          }
      }
      return false;
  }
  
  #ifdef ASSIMP_USE_HUNTER
  #include <utf8.h>
  #else
  #include "../contrib/utf8cpp/source/utf8.h"
  #endif
  
  // ------------------------------------------------------------------------------------------------
  // Convert to UTF8 data
  void BaseImporter::ConvertToUTF8(std::vector<char> &data) {
      //ConversionResult result;
      if (data.size() < 8) {
          throw DeadlyImportError("File is too small");
      }
  
      // UTF 8 with BOM
      if ((uint8_t)data[0] == 0xEF && (uint8_t)data[1] == 0xBB && (uint8_t)data[2] == 0xBF) {
          ASSIMP_LOG_DEBUG("Found UTF-8 BOM ...");
  
          std::copy(data.begin() + 3, data.end(), data.begin());
          data.resize(data.size() - 3);
          return;
      }
  
      // UTF 32 BE with BOM
      if (*((uint32_t *)&data.front()) == 0xFFFE0000) {
  
          // swap the endianness ..
          for (uint32_t *p = (uint32_t *)&data.front(), *end = (uint32_t *)&data.back(); p <= end; ++p) {
              AI_SWAP4P(p);
          }
      }
  
      // UTF 32 LE with BOM
      if (*((uint32_t *)&data.front()) == 0x0000FFFE) {
          ASSIMP_LOG_DEBUG("Found UTF-32 BOM ...");
  
          std::vector<char> output;
          int *ptr = (int *)&data[0];
          int *end = ptr + (data.size() / sizeof(int)) + 1;
          utf8::utf32to8(ptr, end, back_inserter(output));
          return;
      }
  
      // UTF 16 BE with BOM
      if (*((uint16_t *)&data.front()) == 0xFFFE) {
          // Check to ensure no overflow can happen
          if(data.size() % 2 != 0) {
              return;
          }
          // swap the endianness ..
          for (uint16_t *p = (uint16_t *)&data.front(), *end = (uint16_t *)&data.back(); p <= end; ++p) {
              ByteSwap::Swap2(p);
          }
      }
  
      // UTF 16 LE with BOM
      if (*((uint16_t *)&data.front()) == 0xFEFF) {
          ASSIMP_LOG_DEBUG("Found UTF-16 BOM ...");
  
          std::vector<unsigned char> output;
          utf8::utf16to8(data.begin(), data.end(), back_inserter(output));
          return;
      }
  }
  
  // ------------------------------------------------------------------------------------------------
  // Convert to UTF8 data to ISO-8859-1
  void BaseImporter::ConvertUTF8toISO8859_1(std::string &data) {
      size_t size = data.size();
      size_t i = 0, j = 0;
  
      while (i < size) {
          if ((unsigned char)data[i] < (size_t)0x80) {
              data[j] = data[i];
          } else if (i < size - 1) {
              if ((unsigned char)data[i] == 0xC2) {
                  data[j] = data[++i];
              } else if ((unsigned char)data[i] == 0xC3) {
                  data[j] = ((unsigned char)data[++i] + 0x40);
              } else {
                  std::stringstream stream;
                  stream << "UTF8 code " << std::hex << data[i] << data[i + 1] << " can not be converted into ISA-8859-1.";
                  ASSIMP_LOG_ERROR(stream.str());
  
                  data[j++] = data[i++];
                  data[j] = data[i];
              }
          } else {
              ASSIMP_LOG_ERROR("UTF8 code but only one character remaining");
  
              data[j] = data[i];
          }
  
          i++;
          j++;
      }
  
      data.resize(j);
  }
  
  // ------------------------------------------------------------------------------------------------
  void BaseImporter::TextFileToBuffer(IOStream *stream,
          std::vector<char> &data,
          TextFileMode mode) {
      ai_assert(nullptr != stream);
  
      const size_t fileSize = stream->FileSize();
      if (mode == FORBID_EMPTY) {
          if (!fileSize) {
              throw DeadlyImportError("File is empty");
          }
      }
  
      data.reserve(fileSize + 1);
      data.resize(fileSize);
      if (fileSize > 0) {
          if (fileSize != stream->Read(&data[0], 1, fileSize)) {
              throw DeadlyImportError("File read error");
          }
  
          ConvertToUTF8(data);
      }
  
      // append a binary zero to simplify string parsing
      data.push_back(0);
  }
  
  // ------------------------------------------------------------------------------------------------
  namespace Assimp {
  // Represents an import request
  struct LoadRequest {
      LoadRequest(const std::string &_file, unsigned int _flags, const BatchLoader::PropertyMap *_map, unsigned int _id) :
              file(_file),
              flags(_flags),
              refCnt(1),
              scene(nullptr),
              loaded(false),
              id(_id) {
          if (_map) {
              map = *_map;
          }
      }
  
      bool operator==(const std::string &f) const {
          return file == f;
      }
  
      const std::string file;
      unsigned int flags;
      unsigned int refCnt;
      aiScene *scene;
      bool loaded;
      BatchLoader::PropertyMap map;
      unsigned int id;
  };
  } // namespace Assimp
  
  // ------------------------------------------------------------------------------------------------
  // BatchLoader::pimpl data structure
  struct Assimp::BatchData {
      BatchData(IOSystem *pIO, bool validate) :
              pIOSystem(pIO), pImporter(nullptr), next_id(0xffff), validate(validate) {
          ai_assert(nullptr != pIO);
  
          pImporter = new Importer();
          pImporter->SetIOHandler(pIO);
      }
  
      ~BatchData() {
          pImporter->SetIOHandler(nullptr); /* get pointer back into our possession */
          delete pImporter;
      }
  
      // IO system to be used for all imports
      IOSystem *pIOSystem;
  
      // Importer used to load all meshes
      Importer *pImporter;
  
      // List of all imports
      std::list<LoadRequest> requests;
  
      // Base path
      std::string pathBase;
  
      // Id for next item
      unsigned int next_id;
  
      // Validation enabled state
      bool validate;
  };
  
  typedef std::list<LoadRequest>::iterator LoadReqIt;
  
  // ------------------------------------------------------------------------------------------------
  BatchLoader::BatchLoader(IOSystem *pIO, bool validate) {
      ai_assert(nullptr != pIO);
  
      m_data = new BatchData(pIO, validate);
  }
  
  // ------------------------------------------------------------------------------------------------
  BatchLoader::~BatchLoader() {
      // delete all scenes what have not been polled by the user
      for (LoadReqIt it = m_data->requests.begin(); it != m_data->requests.end(); ++it) {
          delete (*it).scene;
      }
      delete m_data;
  }
  
  // ------------------------------------------------------------------------------------------------
  void BatchLoader::setValidation(bool enabled) {
      m_data->validate = enabled;
  }
  
  // ------------------------------------------------------------------------------------------------
  bool BatchLoader::getValidation() const {
      return m_data->validate;
  }
  
  // ------------------------------------------------------------------------------------------------
  unsigned int BatchLoader::AddLoadRequest(const std::string &file,
          unsigned int steps /*= 0*/, const PropertyMap *map /*= nullptr*/) {
      ai_assert(!file.empty());
  
      // check whether we have this loading request already
      for (LoadReqIt it = m_data->requests.begin(); it != m_data->requests.end(); ++it) {
          // Call IOSystem's path comparison function here
          if (m_data->pIOSystem->ComparePaths((*it).file, file)) {
              if (map) {
                  if (!((*it).map == *map)) {
                      continue;
                  }
              } else if (!(*it).map.empty()) {
                  continue;
              }
  
              (*it).refCnt++;
              return (*it).id;
          }
      }
  
      // no, we don't have it. So add it to the queue ...
      m_data->requests.emplace_back(file, steps, map, m_data->next_id);
      return m_data->next_id++;
  }
  
  // ------------------------------------------------------------------------------------------------
  aiScene *BatchLoader::GetImport(unsigned int which) {
      for (LoadReqIt it = m_data->requests.begin(); it != m_data->requests.end(); ++it) {
          if ((*it).id == which && (*it).loaded) {
              aiScene *sc = (*it).scene;
              if (!(--(*it).refCnt)) {
                  m_data->requests.erase(it);
              }
              return sc;
          }
      }
      return nullptr;
  }
  
  // ------------------------------------------------------------------------------------------------
  void BatchLoader::LoadAll() {
      // no threaded implementation for the moment
      for (LoadReqIt it = m_data->requests.begin(); it != m_data->requests.end(); ++it) {
          // force validation in debug builds
          unsigned int pp = (*it).flags;
          if (m_data->validate) {
              pp |= aiProcess_ValidateDataStructure;
          }
  
          // setup config properties if necessary
          ImporterPimpl *pimpl = m_data->pImporter->Pimpl();
          pimpl->mFloatProperties = (*it).map.floats;
          pimpl->mIntProperties = (*it).map.ints;
          pimpl->mStringProperties = (*it).map.strings;
          pimpl->mMatrixProperties = (*it).map.matrices;
  
          if (!DefaultLogger::isNullLogger()) {
              ASSIMP_LOG_INFO("%%% BEGIN EXTERNAL FILE %%%");
              ASSIMP_LOG_INFO("File: ", (*it).file);
          }
          m_data->pImporter->ReadFile((*it).file, pp);
          (*it).scene = m_data->pImporter->GetOrphanedScene();
          (*it).loaded = true;
  
          ASSIMP_LOG_INFO("%%% END EXTERNAL FILE %%%");
      }
  }
  