png_error (png_ptr, (png_const_charp) "Read Error");
memcpy (data,tbr->bytes + tbr->index,length);
tbr->index = tbr->index + length;
png_error (png_ptr, (png_const_charp) "Read Error");
memcpy (data,tbr->bytes + tbr->index,length);
tbr->index = tbr->index + length;