Method fillBuffer

Engine/source/core/stream/fileStream.cpp:437–493

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bool FileStream::fillBuffer(const U32 i_startPosition)
{
   AssertFatal(0 != mStreamCaps, "FileStream::fillBuffer: the stream isn't open");
   AssertFatal(false == mDirty, "FileStream::fillBuffer: buffer must be clean to fill");

   // make sure start position and file pointer jive
   if (i_startPosition != mFile->getPosition())
   {
      mFile->setPosition(i_startPosition, Torque::FS::File::Begin);
      if (mFile->getStatus() != Torque::FS::FileNode::Open && mFile->getStatus() != Torque::FS::FileNode::EndOfFile)
      {
         setStatus();
         return(false);
      }
      else
         // update buffer pointer
         mBuffPos = i_startPosition;
   }

   // check if file pointer is at end-of-file
   if (EOS == getStatus())
   {
      // invalidate the buffer
      mBuffHead = BUFFER_INVALID;
      // set the status to end-of-stream
      mEOF = true;
   }
   // otherwise
   else
   {
      U32 blockHead;
      // locate bounds of buffer containing current position
      calcBlockHead(mBuffPos, &blockHead);
      // read as much as possible from input file
      U32 bytesRead = mFile->read((char *)mBuffer + (i_startPosition - blockHead), BUFFER_SIZE - (i_startPosition - blockHead));
      setStatus();
      if (Ok == getStatus() || EOS == getStatus())
      {
         // update buffer pointers
         mBuffHead = i_startPosition;
         mBuffPos = i_startPosition;
         mBuffTail = i_startPosition + bytesRead - 1;
         // update end-of-file status
         if (0 != bytesRead && EOS == getStatus())
         {
            Stream::setStatus(Ok);
            mEOF = true;
         }
      }
      else
      {
         mBuffHead = BUFFER_INVALID;
         return(false);
      }
   }
   return(true);
}