OutputStream Manual

Table of Contents

• About
• Usage
• Further Reading

About

An output stream is used to write data to a resource defined with a maxon::Url. maxon::OutputStreamInterface is based on maxon::BaseStreamInterface.

Usage

maxon::BaseStreamInterface provides these simple functions:

• maxon::OutputStreamInterface::Write(): Writes the given number of bytes from the given buffer into the stream.
• maxon::OutputStreamInterface::Flush(): Flushes the output stream and forces any buffered output bytes to be written.

Note

To append to the end of a file use the flags maxon::OPENSTREAMFLAGS::WRITE_DONT_TRUNCATE and maxon::OPENSTREAMFLAGS::SEEK_TO_END.

  // This example writes a maxon::String into a local file.
 
  // construct file URL
  const maxon::Url url = (targetFolder + maxon::Url("sometext.txt"_s))iferr_return;
 
  // only proceed if file does not exist yet
  if (url.IoDetect() == maxon::IODETECT::NONEXISTENT)
  {
    // define text
    const maxon::String data { "Hello World!" };
    const maxon::BaseArray<maxon::Char> memory = data.GetCString() iferr_return;
 
    // write to file
    const maxon::OutputStreamRef stream = url.OpenOutputStream() iferr_return;
    stream.Write(memory) iferr_return;
    stream.Close() iferr_return;
  }

  // This example loads a file from the web and saves it to the local file system.
 
  // check if the given URL references a file on the web
  const maxon::UrlScheme scheme  = webFile.GetScheme();
  const maxon::Bool      isHTTP  = scheme == maxon::URLSCHEME_HTTP;
  const maxon::Bool      isHTTPS = scheme == maxon::URLSCHEME_HTTPS;
 
  if (isHTTP || isHTTPS)
  {
    // read data
 
    // input stream
    const maxon::InputStreamRef inputStream = webFile.OpenInputStream() iferr_return;
    const maxon::Int64 length = inputStream.GetStreamLength() iferr_return;
 
    maxon::BaseArray<maxon::Char> data;
    data.Resize(length) iferr_return;
 
    inputStream.Read(data) iferr_return;
    inputStream.Close() iferr_return;
 
    // save data to file
 
    // prepare file name
    const maxon::Url localFile = (targetFolder + webFile.GetName())iferr_return;
    // output stream
    const maxon::OutputStreamRef outputStream = localFile.OpenOutputStream() iferr_return;
    // write to file
    outputStream.Write(data) iferr_return;
    outputStream.Close() iferr_return;
  }

Further Reading

• Files & Media
• MAXON API Files & Media
• Url Manual
• InputStream Manual