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https://github.com/fergalmoran/StegoPrint.git
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Fucking line endings
This commit is contained in:
Fergal Moran
404
WaveUtility.cs
404
WaveUtility.cs
@@ -1,203 +1,203 @@
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using System.IO;
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namespace StegoPrint {
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public class WaveUtility {
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/// <summary>
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/// The read-only stream.
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/// Clean wave for hiding,
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/// Carrier wave for extracting
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/// </summary>
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private WaveStream sourceStream;
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/// <summary>Stream to receive the edited carrier wave</summary>
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private Stream destinationStream;
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/// <summary>bits per sample / 8</summary>
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private int bytesPerSample;
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/// <summary>Initializes a new WaveUtility for hiding a message</summary>
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/// <param name="sourceStream">Clean wave</param>
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/// <param name="destinationStream">
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/// Header of the clean wave
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/// This stream will receive the complete carrier wave
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/// </param>
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public WaveUtility (WaveStream sourceStream, Stream destinationStream) : this (sourceStream) {
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this.destinationStream = destinationStream;
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}
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/// <summary>Initializes a new WaveUtility for extracting a message</summary>
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/// <param name="sourceStream">Carrier wave</param>
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public WaveUtility (WaveStream sourceStream) {
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this.sourceStream = sourceStream;
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this.bytesPerSample = sourceStream.Format.wBitsPerSample / 8;
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}
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/// <summary>
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/// Hide [messageStream] in [sourceStream],
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/// write the result to [destinationStream]
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/// </summary>
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/// <param name="messageStream">The message to hide</param>
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/// <param name="keyStream">
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/// A key stream that specifies how many samples shall be
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/// left clean between two changed samples
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/// </param>
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public void Hide (Stream messageStream, Stream keyStream) {
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byte[] waveBuffer = new byte[bytesPerSample];
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byte message, bit, waveByte;
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int messageBuffer; //receives the next byte of the message or -1
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int keyByte; //distance of the next carrier sample
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while ((messageBuffer = messageStream.ReadByte ()) >= 0) {
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//read one byte of the message stream
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message = (byte) messageBuffer;
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//for each bit in message
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for (int bitIndex = 0; bitIndex < 8; bitIndex++) {
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//read a byte from the key
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keyByte = GetKeyValue (keyStream);
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//skip a couple of samples
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for (int n = 0; n < keyByte - 1; n++) {
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//copy one sample from the clean stream to the carrier stream
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sourceStream.Copy (waveBuffer, 0, waveBuffer.Length, destinationStream);
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}
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//read one sample from the wave stream
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sourceStream.Read (waveBuffer, 0, waveBuffer.Length);
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waveByte = waveBuffer[bytesPerSample - 1];
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//get the next bit from the current message byte...
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bit = (byte) (((message & (byte) (1<<bitIndex))> 0) ? 1 : 0);
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//...place it in the last bit of the sample
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if ((bit == 1) && ((waveByte % 2) == 0)) {
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waveByte += 1;
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} else if ((bit == 0) && ((waveByte % 2) == 1)) {
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waveByte -= 1;
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}
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waveBuffer[bytesPerSample - 1] = waveByte;
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//write the result to destinationStream
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destinationStream.Write (waveBuffer, 0, bytesPerSample);
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}
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}
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//copy the rest of the wave without changes
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waveBuffer = new byte[sourceStream.Length - sourceStream.Position];
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sourceStream.Read (waveBuffer, 0, waveBuffer.Length);
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destinationStream.Write (waveBuffer, 0, waveBuffer.Length);
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}
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/// <summary>Extract a message from [sourceStream] into [messageStream]</summary>
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/// <param name="messageStream">Empty stream to receive the extracted message</param>
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/// <param name="keyStream">
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/// A key stream that specifies how many samples shall be
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/// skipped between two carrier samples
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/// </param>
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public void Extract (Stream messageStream, Stream keyStream) {
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byte[] waveBuffer = new byte[bytesPerSample];
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byte message, bit, waveByte;
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int messageLength = 0; //expected length of the message
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int keyByte; //distance of the next carrier sample
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while ((messageLength == 0 || messageStream.Length < messageLength)) {
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//clear the message-byte
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message = 0;
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//for each bit in message
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for (int bitIndex = 0; bitIndex < 8; bitIndex++) {
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//read a byte from the key
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keyByte = GetKeyValue (keyStream);
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//skip a couple of samples
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for (int n = 0; n < keyByte - 1; n++) {
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//read one sample from the wave stream
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sourceStream.Read (waveBuffer, 0, waveBuffer.Length);
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}
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sourceStream.Read (waveBuffer, 0, waveBuffer.Length);
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waveByte = waveBuffer[bytesPerSample - 1];
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//get the last bit of the sample...
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bit = (byte) (((waveByte % 2) == 0) ? 0 : 1);
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//...write it into the message-byte
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message += (byte) (bit << bitIndex);
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}
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//add the re-constructed byte to the message
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messageStream.WriteByte (message);
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if (messageLength == 0 && messageStream.Length == 4) {
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//first 4 bytes contain the message's length
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messageStream.Seek (0, SeekOrigin.Begin);
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messageLength = new BinaryReader (messageStream).ReadInt32 ();
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messageStream.Seek (0, SeekOrigin.Begin);
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messageStream.SetLength (0);
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}
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}
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}
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/// <summary>Counts the samples that will be skipped using the specified key stream</summary>
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/// <param name="keyStream">Key stream</param>
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/// <param name="messageLength">Length of the message</param>
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/// <returns>Minimum length (in samples) of an audio file</returns>
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public static long CheckKeyForMessage (Stream keyStream, long messageLength) {
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long messageLengthBits = messageLength * 8;
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long countRequiredSamples = 0;
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if (messageLengthBits > keyStream.Length) {
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long keyLength = keyStream.Length;
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// read existing key
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byte[] keyBytes = new byte[keyLength];
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keyStream.Read (keyBytes, 0, keyBytes.Length);
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// Every byte stands for the distance between two useable samples.
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// The sum of those distances is the required count of samples.
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countRequiredSamples = SumKeyArray (keyBytes);
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// The key must be repeated, until every bit of the message has a key byte.
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double countKeyCopies = messageLengthBits / keyLength;
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countRequiredSamples = (long) (countRequiredSamples * countKeyCopies);
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} else {
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byte[] keyBytes = new byte[messageLengthBits];
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keyStream.Read (keyBytes, 0, keyBytes.Length);
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countRequiredSamples = SumKeyArray (keyBytes);
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}
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keyStream.Seek (0, SeekOrigin.Begin);
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return countRequiredSamples;
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}
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private static long SumKeyArray (byte[] values) {
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long sum = 0;
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foreach (int value in values) { // '0' causes a distance of one sample,
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// every other key causes a distance of its exact value.
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sum += (value == 0) ? 1 : value;
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}
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return sum;
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}
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/// <summary>
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/// Read the next byte of the key stream.
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/// Reset the stream if it is too short.
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/// </summary>
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/// <param name="keyStream">The key stream</param>
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/// <returns>The next key byte</returns>
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private static byte GetKeyValue (Stream keyStream) {
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int keyValue;
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if ((keyValue = keyStream.ReadByte ()) < 0) {
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keyStream.Seek (0, SeekOrigin.Begin);
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keyValue = keyStream.ReadByte ();
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if (keyValue == 0) { keyValue = 1; }
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}
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return (byte) keyValue;
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}
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}
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using System.IO;
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namespace StegoPrint {
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public class WaveUtility {
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/// <summary>
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/// The read-only stream.
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/// Clean wave for hiding,
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/// Carrier wave for extracting
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/// </summary>
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private WaveStream sourceStream;
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/// <summary>Stream to receive the edited carrier wave</summary>
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private Stream destinationStream;
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/// <summary>bits per sample / 8</summary>
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private int bytesPerSample;
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/// <summary>Initializes a new WaveUtility for hiding a message</summary>
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/// <param name="sourceStream">Clean wave</param>
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/// <param name="destinationStream">
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/// Header of the clean wave
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/// This stream will receive the complete carrier wave
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/// </param>
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public WaveUtility (WaveStream sourceStream, Stream destinationStream) : this (sourceStream) {
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this.destinationStream = destinationStream;
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}
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/// <summary>Initializes a new WaveUtility for extracting a message</summary>
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/// <param name="sourceStream">Carrier wave</param>
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public WaveUtility (WaveStream sourceStream) {
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this.sourceStream = sourceStream;
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this.bytesPerSample = sourceStream.Format.wBitsPerSample / 8;
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}
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/// <summary>
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/// Hide [messageStream] in [sourceStream],
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/// write the result to [destinationStream]
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/// </summary>
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/// <param name="messageStream">The message to hide</param>
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/// <param name="keyStream">
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/// A key stream that specifies how many samples shall be
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/// left clean between two changed samples
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/// </param>
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public void Hide (Stream messageStream, Stream keyStream) {
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byte[] waveBuffer = new byte[bytesPerSample];
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byte message, bit, waveByte;
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int messageBuffer; //receives the next byte of the message or -1
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int keyByte; //distance of the next carrier sample
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while ((messageBuffer = messageStream.ReadByte ()) >= 0) {
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//read one byte of the message stream
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message = (byte) messageBuffer;
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//for each bit in message
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for (int bitIndex = 0; bitIndex < 8; bitIndex++) {
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//read a byte from the key
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keyByte = GetKeyValue (keyStream);
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//skip a couple of samples
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for (int n = 0; n < keyByte - 1; n++) {
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//copy one sample from the clean stream to the carrier stream
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sourceStream.Copy (waveBuffer, 0, waveBuffer.Length, destinationStream);
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}
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//read one sample from the wave stream
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sourceStream.Read (waveBuffer, 0, waveBuffer.Length);
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waveByte = waveBuffer[bytesPerSample - 1];
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//get the next bit from the current message byte...
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bit = (byte) (((message & (byte) (1<<bitIndex))> 0) ? 1 : 0);
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//...place it in the last bit of the sample
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if ((bit == 1) && ((waveByte % 2) == 0)) {
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waveByte += 1;
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} else if ((bit == 0) && ((waveByte % 2) == 1)) {
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waveByte -= 1;
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}
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waveBuffer[bytesPerSample - 1] = waveByte;
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//write the result to destinationStream
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destinationStream.Write (waveBuffer, 0, bytesPerSample);
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}
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}
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//copy the rest of the wave without changes
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waveBuffer = new byte[sourceStream.Length - sourceStream.Position];
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sourceStream.Read (waveBuffer, 0, waveBuffer.Length);
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destinationStream.Write (waveBuffer, 0, waveBuffer.Length);
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}
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/// <summary>Extract a message from [sourceStream] into [messageStream]</summary>
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/// <param name="messageStream">Empty stream to receive the extracted message</param>
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/// <param name="keyStream">
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/// A key stream that specifies how many samples shall be
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/// skipped between two carrier samples
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/// </param>
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public void Extract (Stream messageStream, Stream keyStream) {
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byte[] waveBuffer = new byte[bytesPerSample];
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byte message, bit, waveByte;
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int messageLength = 0; //expected length of the message
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int keyByte; //distance of the next carrier sample
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while ((messageLength == 0 || messageStream.Length < messageLength)) {
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//clear the message-byte
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message = 0;
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//for each bit in message
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for (int bitIndex = 0; bitIndex < 8; bitIndex++) {
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//read a byte from the key
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keyByte = GetKeyValue (keyStream);
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//skip a couple of samples
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for (int n = 0; n < keyByte - 1; n++) {
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//read one sample from the wave stream
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sourceStream.Read (waveBuffer, 0, waveBuffer.Length);
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}
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sourceStream.Read (waveBuffer, 0, waveBuffer.Length);
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waveByte = waveBuffer[bytesPerSample - 1];
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//get the last bit of the sample...
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bit = (byte) (((waveByte % 2) == 0) ? 0 : 1);
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//...write it into the message-byte
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message += (byte) (bit << bitIndex);
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}
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//add the re-constructed byte to the message
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messageStream.WriteByte (message);
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if (messageLength == 0 && messageStream.Length == 4) {
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//first 4 bytes contain the message's length
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messageStream.Seek (0, SeekOrigin.Begin);
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messageLength = new BinaryReader (messageStream).ReadInt32 ();
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messageStream.Seek (0, SeekOrigin.Begin);
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messageStream.SetLength (0);
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}
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}
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}
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/// <summary>Counts the samples that will be skipped using the specified key stream</summary>
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/// <param name="keyStream">Key stream</param>
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/// <param name="messageLength">Length of the message</param>
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/// <returns>Minimum length (in samples) of an audio file</returns>
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public static long CheckKeyForMessage (Stream keyStream, long messageLength) {
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long messageLengthBits = messageLength * 8;
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long countRequiredSamples = 0;
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if (messageLengthBits > keyStream.Length) {
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long keyLength = keyStream.Length;
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// read existing key
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byte[] keyBytes = new byte[keyLength];
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keyStream.Read (keyBytes, 0, keyBytes.Length);
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// Every byte stands for the distance between two useable samples.
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// The sum of those distances is the required count of samples.
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countRequiredSamples = SumKeyArray (keyBytes);
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// The key must be repeated, until every bit of the message has a key byte.
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double countKeyCopies = messageLengthBits / keyLength;
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countRequiredSamples = (long) (countRequiredSamples * countKeyCopies);
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} else {
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byte[] keyBytes = new byte[messageLengthBits];
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keyStream.Read (keyBytes, 0, keyBytes.Length);
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countRequiredSamples = SumKeyArray (keyBytes);
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}
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keyStream.Seek (0, SeekOrigin.Begin);
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return countRequiredSamples;
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}
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private static long SumKeyArray (byte[] values) {
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long sum = 0;
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foreach (int value in values) { // '0' causes a distance of one sample,
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// every other key causes a distance of its exact value.
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sum += (value == 0) ? 1 : value;
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}
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return sum;
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}
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/// <summary>
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/// Read the next byte of the key stream.
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/// Reset the stream if it is too short.
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/// </summary>
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/// <param name="keyStream">The key stream</param>
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/// <returns>The next key byte</returns>
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private static byte GetKeyValue (Stream keyStream) {
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int keyValue;
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if ((keyValue = keyStream.ReadByte ()) < 0) {
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keyStream.Seek (0, SeekOrigin.Begin);
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keyValue = keyStream.ReadByte ();
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if (keyValue == 0) { keyValue = 1; }
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}
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return (byte) keyValue;
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}
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}
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}
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