legalizeFATFilename function

String legalizeFATFilename(String filename, { String replacement = '_', String placeholder = 'untitled', })

Sanitizes the filename for FAT systems.

replacement is used to replace illegal characters. If the filename is empty after sanitization, it will be replaced with placeholder. It is recommended to not use an empty replacement and an empty placeholder as it may result in an empty filename.

Implementation

String legalizeFATFilename(String filename, {String replacement = '_', String placeholder = 'untitled'}) {
  var result = filename;

  result = result.replaceAll(controlCharacterRegex, replacement);

  // Replace illegal characters
  result = result.replaceAll(illegalFATCharactersRegex, replacement);

  // If the filename is empty, replace it with a placeholder
  if (result.isEmpty || isRelativePath(result)) {
    result = placeholder;
  }

  // Check length
  if (result.length > 255) {
    result = result.substring(0, 255);
  }

  return result;
}