/// <summary>
/// Counts available space for data hiding of all supported avi stream types
/// </summary>
/// <param name="avifh">.avi file handler</param>
/// <returns>(Junk available size, Audio available size, Compressed video available size, Uncompressed video available size)</returns>
public static (int, int, int, int) GetStreamsAvailableChunksSize(AVIFileHandler avifh)
{
Int32 junkSize = 0, vidsCompressSize = 0, vidsUncompressedSize = 0, audsSize = 0;
Dictionary <Int32, CHUNK> chunkType;
if (avifh.Chunks.TryGetValue(AVIFileHandler.JUNK_CHUNK, out chunkType))
{
junkSize = GetAvailableSize(chunkType);
}
if (avifh.Chunks.TryGetValue(AVIFileHandler.AUDIO_CHUNK, out chunkType))
{
audsSize = GetAvailableSize(chunkType);
}
if (avifh.Chunks.TryGetValue(AVIFileHandler.VIDEO_CHUNK_COMPRESSED, out chunkType))
{
vidsCompressSize = GetAvailableSize(chunkType);
}
if (avifh.Chunks.TryGetValue(AVIFileHandler.VIDEO_CHUNK_UNCOMPRESSED, out chunkType))
{
vidsUncompressedSize = GetAvailableSize(chunkType);
}
return(junkSize, vidsUncompressedSize, vidsCompressSize, audsSize);
}
/// <summary>
/// Command line parser success handler
/// <see href="https://github.com/commandlineparser/commandline.git"></see>
/// </summary>
/// <param name="options">Parsed options</param>
public static void RunOptionsAndReturnExitCode(Options options)
{
if (options.Action == Options.Actions.hide && options.Message == null)
{
IOUtils.ConsolePrintFailure();
Console.WriteLine("Message has to be specified in hide mode.");
Exit(-1);
}
string message;
if (options.Message.StartsWith("file:"))
{
message = IOUtils.LoadMessage(options.Message.Split(':')[1]);
}
else
{
message = options.Message;
}
if (message == null)
{
IOUtils.ConsolePrintFailure();
Console.WriteLine("Message cannot be empty.");
Exit(-1);
}
byte[] avi = IOUtils.LoadAvi(options.FilePath);
if (avi == null)
{
Exit(-1);
}
AVIFileHandler avifh = new AVIFileHandler(avi);
if (options.Action == Options.Actions.extract)
{
string hiddenMessage = StenogrpahyUtils.ExtractMessage(avifh, options.Used);
IOUtils.ConsolePrintSuccess();
Console.WriteLine($"Hidden message is: {hiddenMessage}");
}
else
{
if (StenogrpahyUtils.HideMessage(avifh, message, options.Force, options.Used))
{
IOUtils.ConsolePrintSuccess();
Console.WriteLine("Hiding data.");
IOUtils.SaveAvi(options.OutputFilePath, avifh.Avi);
}
else
{
IOUtils.ConsolePrintFailure();
Console.WriteLine("Message hidding failed.");
}
}
}
/// <summary>
/// Hides message into .avi file
/// </summary>
/// <param name="avifh">.avi file handler</param>
/// <param name="message">String to hide</param>
/// <param name="force">Hide into compressed streams</param>
/// <param name="hideTo">List of streams the message will be hidden into (in given order)</param>
/// <returns>True if message was hide successfuly else false</returns>
public static bool HideMessage(AVIFileHandler avifh, string message, bool force, IEnumerable <Options.DataTypes> hideTo)
{
message += MESSAGE_END;
if (!CheckAvailableSpace(avifh, message, hideTo))
{
IOUtils.ConsolePrintFailure();
Console.WriteLine("There is not enough space for message");
return(false);
}
else
{
IOUtils.ConsolePrintSuccess();
Console.WriteLine("Space check.");
}
foreach (Options.DataTypes type in hideTo)
{
Dictionary <Int32, CHUNK> chunks;
if (CheckCompression(avifh.IsStreamUncompressed(type), force, type))
{
if (avifh.Chunks.TryGetValue(AVIFileHandler.GetChunkName(type), out chunks))
{
foreach (KeyValuePair <Int32, CHUNK> kvp in chunks)
{
message = HideData(avifh.Avi, kvp.Key, kvp.Value.ckSize, message);
if (message == String.Empty)
{
return(true);
}
}
}
}
}
return(false);
}
/// <summary>
/// Extracts hidden message from .avi file
/// </summary>
/// <param name="avifh">.avi file handler</param>
/// <param name="extractFrom">List of streams the message will be extracted from (in given order)</param>
/// <returns>Extracted message</returns>
public static string ExtractMessage(AVIFileHandler avifh, IEnumerable <Options.DataTypes> extractFrom)
{
string message = "";
bool EndReached = false;
foreach (Options.DataTypes type in extractFrom)
{
Dictionary <Int32, CHUNK> chunks;
if (avifh.Chunks.TryGetValue(AVIFileHandler.GetChunkName(type), out chunks))
{
foreach (KeyValuePair <Int32, CHUNK> kvp in chunks)
{
EndReached = ExtractData(avifh.Avi, kvp.Key, kvp.Value.ckSize, ref message);
if (EndReached)
{
return(message);
}
}
}
}
return(null);
}
/// <summary>
/// Checks if there is enough free space to hide message
/// </summary>
/// <param name="avifh">.avi file handler</param>
/// <param name="message">Message to hide</param>
/// <param name="streams">List of stream for message hiding</param>
/// <returns>true if there is enough space for message hiding else false</returns>
private static bool CheckAvailableSpace(AVIFileHandler avifh, string message, IEnumerable <Options.DataTypes> streams)
{
(Int32, Int32, Int32, Int32)chunkSizes = GetStreamsAvailableChunksSize(avifh);
IOUtils.ConsolePrintInfo();
Console.WriteLine($"Available free junk space: {chunkSizes.Item1}B");
IOUtils.ConsolePrintInfo();
Console.WriteLine($"Available free video space: {chunkSizes.Item2 + chunkSizes.Item3}B");
IOUtils.ConsolePrintInfo();
Console.WriteLine($"Available free audio space: {chunkSizes.Item4}B");
int[] sizes = new int[3] {
chunkSizes.Item1, chunkSizes.Item2 + chunkSizes.Item3, chunkSizes.Item4
};
int size = 0;
foreach (int type in streams)
{
size += sizes[type];
}
return(size / 8 > message.Length);
}
