Method _write

Engine/source/core/stream/fileStream.cpp:344–426

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bool FileStream::_write(const U32 i_numBytes, const void *i_pBuffer)
{
   AssertFatal(0 != mStreamCaps, "FileStream::_write: the stream isn't open");
   AssertFatal(NULL != i_pBuffer || i_numBytes == 0, "FileStream::_write: NULL source buffer pointer on non-zero write request");

   if (!hasCapability(Stream::StreamWrite))
   {
      AssertFatal(false, "FileStream::_write: file stream lacks capability");
      Stream::setStatus(IllegalCall);
      return(false);
   }

   // exit on pre-existing errors
   if (Ok != getStatus() && EOS != getStatus())
      return(false);

   // if a request of non-zero length was made
   if (0 != i_numBytes)
   {
      U8 *pSrc = (U8 *)i_pBuffer;
      U32 writeSize;
      U32 remaining = i_numBytes;
      U32 bytesWrit;
      U32 blockHead;
      U32 blockTail;

      // check if the buffer is valid
      if (BUFFER_INVALID != mBuffHead)
      {
         // copy as much as possible from the source to the buffer
         calcBlockBounds(mBuffHead, &blockHead, &blockTail);
         writeSize = (mBuffPos > blockTail) ? 0 : blockTail - mBuffPos + 1;
         writeSize = getMin(writeSize, remaining);

         AssertFatal(0 == writeSize || (mBuffPos - blockHead) < BUFFER_SIZE, "FileStream::_write: out of bounds buffer position");
         dMemcpy(mBuffer + (mBuffPos - blockHead), pSrc, writeSize);
         // reduce the remaining amount to be written
         remaining -= writeSize;
         // advance the buffer pointers
         mBuffPos += writeSize;
         mBuffTail = getMax(mBuffTail, mBuffPos - 1);
         pSrc += writeSize;
         // mark the buffer dirty
         if (0 < writeSize)
            mDirty = true;
      }

      // if the request wasn't satisfied by the buffer
      if (0 < remaining)
      {
         // flush the buffer if its dirty, since we now need to go to disk
         if (mDirty)
            flush();

         // make sure we know the current write location in the underlying file
         mBuffPos = mFile->getPosition();
         calcBlockBounds(mBuffPos, &blockHead, &blockTail);