Develop Reference

Decreasing volume of .wav file creates heavy distortion

I have a problem that just baffles me. I import a .wav file and read them as bytes. Then I turn them into integers that I then all divide by 2 (or some other number) in order to decrease the volume. Then I make a new .wav file into which I put the new data. The result is loud and heavy distortion over the original track.
Scroll to the Main() method for the relevant (C#-)code:
using System;
using System.IO;
namespace ConsoleApp2 {
class basic {
public static byte[] bit32(int num) { //turns int into byte array of length 4
byte[] numbyt = new byte[4] { 0x00, 0x00, 0x00, 0x00 };
int pow;
for (int k = 3; k >= 0; k--) {
pow = (int)Math.Pow(16, 2*k + 1);
numbyt[k] += (byte)(16*(num/pow));
num -= numbyt[k]*(pow/16);
numbyt[k] += (byte)(num/(pow/16));
num -= (num/(pow/16))*pow/16;
}
return numbyt;
}
public static byte[] bit16(int num) { //turns int into byte array of length 2
if (num < 0) {
num += 65535;
}
byte[] numbyt = new byte[2] { 0x00, 0x00 };
int pow;
for (int k = 1; k >= 0; k--) {
pow = (int)Math.Pow(16, 2*k + 1);
numbyt[k] += (byte)(16*(num/pow));
num -= numbyt[k]*(pow/16);
numbyt[k] += (byte)(num/(pow/16));
num -= (num/(pow/16))*pow/16;
}
return numbyt;
}
public static int bitint16(byte[] numbyt) { //turns byte array of length 2 into int
int num = 0;
num += (int)Math.Pow(16, 2)*numbyt[1];
num += numbyt[0];
return num;
}
}
class wavfile: FileStream {
public wavfile(string name, int len) : base(name, FileMode.Create) {
int samplerate = 44100;
byte[] riff = new byte[] { 0x52, 0x49, 0x46, 0x46 };
this.Write(riff, 0, 4);
byte[] chunksize;
chunksize = basic.bit32(36 + len*4);
this.Write(chunksize, 0, 4);
byte[] wavebyte = new byte[4] { 0x57, 0x41, 0x56, 0x45 };
this.Write(wavebyte, 0, 4);
byte[] fmt = new byte[] { 0x66, 0x6d, 0x74, 0x20 };
this.Write(fmt, 0, 4);
byte[] subchunk1size = new byte[] { 0x10, 0x00, 0x00, 0x00 };
this.Write(subchunk1size, 0, 4);
byte[] formchann = new byte[] { 0x01, 0x00, 0x02, 0x00 };
this.Write(formchann, 0, 4);
byte[] sampleratebyte = basic.bit32(samplerate);
this.Write(sampleratebyte, 0, 4);
byte[] byterate = basic.bit32(samplerate*4);
this.Write(byterate, 0, 4);
byte[] blockalign = new byte[] { 0x04, 0x00 };
this.Write(blockalign, 0, 2);
byte[] bits = new byte[] { 0x10, 0x00 };
this.Write(bits, 0, 2);
byte[] data = new byte[] { 0x64, 0x61, 0x74, 0x61 };
this.Write(data, 0, 4);
byte[] samplesbyte = basic.bit32(len*4);
this.Write(samplesbyte, 0, 4);
}
public void sound(int[] w, int len, wavfile wavorigin = null) {
byte[] wavbyt = new byte[len*4];
for (int t = 0; t < len*2; t++) {
byte[] wavbit16 = basic.bit16(w[t]);
wavbyt[2*t] = wavbit16[0];
wavbyt[2*t + 1] = wavbit16[1];
}
this.Write(wavbyt, 0, len*4);
System.Media.SoundPlayer player = new System.Media.SoundPlayer();
player.SoundLocation = this.Name;
while (true) {
player.Play();
Console.WriteLine("repeat?");
if (Console.ReadLine() == "no") {
break;
}
}
}
}
class Program {
static void Main() {
int[] song = new int[45000*2];
byte[] songbyt = File.ReadAllBytes("name.wav"); //use your stereo, 16bits per sample wav-file
for (int t = 0; t < 45000*2; t++) {
byte[] songbytsamp = new byte[2] { songbyt[44 + 2*t], songbyt[44 + 2*t + 1] }; //I skip the header
song[t] = basic.bitint16(songbytsamp)/2; //I divide by 2 here, remove the "/2" to hear the normal sound again
//song[t] *= 2;
}
wavfile wav = new wavfile("test.wav", 45000); //constructor class that writes the header of a .wav file
wav.sound(song, 45000); //method that writes the data from "song" into the .wav file
}
}
}
The problem is not the rounding down that happens when you divide an odd number by 2; you can uncomment the line that says song[t] *= 2; and hear for yourself that all of the distortion has completely disappeared again.
I must be making a small stupid mistake somewhere, but I cannot find it. I just want to make the sound data quieter to avoid distortion when I add more sounds to it.

Well, I knew it would be something stupid, and I was right. I forgot to account for the fact that negative numbers are written in signed 16 bit language as the numbers above 2^15, and when you divide by 2, you push them into (very large) positive values. I altered my code to substract 2^16 from any number that's above 2^15 before dividing by 2. I have to thank this person though: How to reduce volume of wav stream?
If this means that my question was a duplicate, then go ahead and delete it, but I'm letting it stay for now, because someone else might find it helpful.

Using Math.Pow to do bit and byte operations is a really bad idea. That function takes double values as inputs and returns a double. It also does exponentiation (not a trivial operation). Using traditional bit shift and mask operations is clearer, much faster and less likely to introduce noise (because of the inaccuracy of doubles).
As you noticed, you really want to work with unsigned quantities (like uint/UInt32 and ushort/UInt16). Sign extension trips up everyone when doing this sort of work.
This is not a full answer to your question, but it does present a way to do the byte operations that is arguably better.
First, create a small struct to hold a combination of a bit-mask and a shift quantity:
public struct MaskAndShift {
public uint Mask {get; set;}
public int Shift {get; set;}
}
Then I create two arrays of these structs for describing what should be done to extract individual bytes from a uint or a ushort. I put them both in a static class named Worker:
public static class Worker {
public static MaskAndShift[] Mask32 = new MaskAndShift[] {
new MaskAndShift {Mask = 0xFF000000, Shift = 24},
new MaskAndShift {Mask = 0x00FF0000, Shift = 16},
new MaskAndShift {Mask = 0x0000FF00, Shift = 8},
new MaskAndShift {Mask = 0x000000FF, Shift = 0},
};
public static MaskAndShift[] Mask16 = new MaskAndShift[] {
new MaskAndShift {Mask = 0x0000FF00, Shift = 8},
new MaskAndShift {Mask = 0x000000FF, Shift = 0},
};
}
Looking at the first entry in the first array, it says "to extract the first byte from a uint, mask that uint with 0xFF000000 and shift the result 24 bits to the right". If you have endian-ness issues, you can simply re-order the entries in the array.
Then I created this static function (in the Worker class) to convert a uint / UInt32 to an array of four bytes:
public static byte[] UintToByteArray (uint input) {
var bytes = new byte[4];
int i = 0;
foreach (var maskPair in Mask32) {
var masked = input & maskPair.Mask;
if (maskPair.Shift != 0) {
masked >>= maskPair.Shift;
}
bytes[i++] = (byte) masked;
}
return bytes;
}
The code to do the same operation for a 16 bit ushort (aka UInt16) looks nearly the same (there's probably an opportunity for some refactoring here):
public static byte[] UShortToByteArray (ushort input) {
var bytes = new byte[2];
int i = 0;
foreach (var maskPair in Mask16) {
var masked = input & maskPair.Mask;
if (maskPair.Shift != 0) {
masked >>= maskPair.Shift;
}
bytes[i++] = (byte) masked;
}
return bytes;
}
The reverse operation is much simpler (however, if you have endian-ness issues, you'll need to write the code). Here I just take the entries of the array, add them into a value and shift the result:
public static uint ByteArrayToUint (byte[] bytes) {
uint result = 0;
//note that the first time through, result is zero, so shifting is a noop
foreach (var b in bytes){
result <<= 8;
result += b;
}
return result;
}
Doing this for the 16 bit version ends up being effectively the same code, so...
public static ushort ByteArrayToUshort (byte[] bytes) {
return (ushort) ByteArrayToUint(bytes);
}
Bit-twiddling never works the first time. So I wrote some test code:
public static void Main(){
//pick a nice obvious pattern
uint bit32Test = (((0xF1u * 0x100u) + 0xE2u) * 0x100u + 0xD3u) * 0x100u + 0xC4u;
Console.WriteLine("Start");
Console.WriteLine("Input 32 Value: " + bit32Test.ToString("X"));
var bytes32 = Worker.UintToByteArray(bit32Test);
foreach (var b in bytes32){
Console.WriteLine(b.ToString("X"));
}
Console.WriteLine();
ushort bit16Test = (ushort)((0xB5u * 0x100u) + 0xA6u);
Console.WriteLine("Input 16 Value: " + bit16Test.ToString("X"));
var bytes16 = Worker.UShortToByteArray(bit16Test);
foreach (var b in bytes16){
Console.WriteLine(b.ToString("X"));
}
Console.WriteLine("\r\nNow the reverse");
uint reconstitued32 = Worker.ByteArrayToUint(bytes32);
Console.WriteLine("Reconstituted 32: " + reconstitued32.ToString("X"));
ushort reconstitued16 = Worker.ByteArrayToUshort(bytes16);
Console.WriteLine("Reconstituted 16: " + reconstitued16.ToString("X"));
}
The output from that test code looks like:
Start
Input 32 Value: F1E2D3C4
F1
E2
D3
C4
Input 16 Value: B5A6
B5
A6
Now the reverse
Reconstituted 32: F1E2D3C4
Reconstituted 16: B5A6
Also note that I do everything in hexadecimal - it makes everything so much easier to read and to understand.

C# - Reading Sequence of Hex Bytes in Binary

So I've been googling & googling for this, but I can't find a solution for my case. I could find things about byte arrays. but I hope there's also a simpler solution for my case.
Maybe it's just me using the wrong search terms, don't know.
Anyways, I already have a kinda working code which is:
static void Main(string[] args)
{
// Open the file to search in
BinaryReader br = new BinaryReader(File.OpenRead("D:/Users/Joey/Desktop/prod"));
for (int i = 0; i <= br.BaseStream.Length; i++)
{
// Search the file for the given byte
if (br.BaseStream.ReadByte() == (byte)0xC0)
{
Console.WriteLine("Found the byte at offset " + i); //write to the console on which offset it has been found
}
}
}
This example works.
However, I need it to be able to search for more than just one byte.
For example: C0035FD6
I feel like I'm missing something so simple, but I just can't seem to figure it out.
If anyone has gotten a solution for me, that would be great :D

You can use this extension to search for AOB:
public static class StreamExtensions
{
public static IEnumerable<long> ScanAOB(this Stream stream, params byte[] aob)
{
long position;
byte[] buffer = new byte[aob.Length - 1];
while ((position = stream.Position) < stream.Length)
{
if (stream.ReadByte() != aob[0]) continue;
if (stream.Read(buffer, 0, aob.Length - 1) == 0) continue;
if (buffer.SequenceEqual(aob.Skip(1)))
{
yield return position;
}
}
}
public static IEnumerable<long> ScanAOB(this Stream stream, params byte?[] aob)
{
long position;
byte[] buffer = new byte[aob.Length - 1];
while ((position = stream.Position) < stream.Length)
{
if (stream.ReadByte() != aob[0]) continue;
if (stream.Read(buffer, 0, aob.Length - 1) == 0) continue;
if (buffer.Cast<byte?>().SequenceEqual(aob.Skip(1), new AobComparer()))
{
yield return position;
}
}
}
private class AobComparer : IEqualityComparer<byte?>
{
public bool Equals(byte? x, byte? y) => x == null || y == null || x == y;
public int GetHashCode(byte? obj) => obj?.GetHashCode() ?? 0;
}
}
Example:
void Main()
{
using (var stream = new MemoryStream(FakeData().ToArray()))
{
stream.ScanAOB(0x1, 0x2).Dump("Addresses of: 01 02");
stream.Position = 0;
stream.ScanAOB(0x03, 0x12).Dump("Addresses of: 03 12");
stream.Position = 0;
stream.ScanAOB(0x04, null, 0x06).Dump("Addresses of: 04 ?? 06");
}
}
// Define other methods and classes here
IEnumerable<byte> FakeData()
{
return Enumerable.Range(0, 2)
.SelectMany(_ => Enumerable.Range(0, 255))
.Select(x => (byte)x);
}

Give this a shot. You will need to verify the arrays are correct. In a binary stream, a byte array is just a collection of bytes starting at offset with count bytes as its size.
//here is where you initialize your array. you may need to tweak the values to match your byte range (array)
byte[] dataArray = new byte[9] { 0x93, 0x0E, 0x40, 0xF9, 0x53, 0x00, 0x00, 0xB5, 0xDE };
//here is where you initialize the NEW array you want to write where your matching array lives
byte[] newArray = new byte[9] { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
// Open the file to search in
BinaryReader br = new BinaryReader(File.OpenRead("D:/Users/Joey/Desktop/prod"));
for (int i = 0; i <= br.BaseStream.Length; i++)
{
// Search the file for the STARTING byte of my match
if (br.BaseStream.ReadByte() == (byte)0x93)
{
Console.WriteLine("Found the starting byte at offset " + i); //write to the console on which offset it has been found
byte[] tempArray = new byte[9];
tempArray = br.ReadBytes(9);
//now compare the arrays to see if you have a full match:
int matched = 0;
for (int j=0; j<tempArray.Length; j++)
{
if(tempArray[j] == dataArray[j])
{
matched++;
}
}
//if the arrays match, write your new values:
if(matched == tempArray.Length-1)
{
br.BaseStream.Write(newArray, i, 9);
break; //exit the loop when finished
}
}
}

Convert little endian to big endian in c#

I want to convert string "8BABEEF9D2472E65" to big endian.
I already input in this function, I receive UINT Size error.. How can i do?
Function :
string bigToLittle(string data)
{
int number = Convert.ToInt32(data, 16);
byte[] bytes = BitConverter.GetBytes(number);
string retval = "";
foreach (byte b in bytes)
retval += b.ToString("X2");
return retval;
}

I think you can use System.Runtime.Remoting.Metadata.W3cXsd2001.SoapHexBinary class.
string input = "8BABEEF9D2472E65";
var output = new SoapHexBinary(SoapHexBinary.Parse(input).Value.Reverse().ToArray())
.ToString();
Output: 652E47D2F9EEAB8B
Or Maybe
var output = IPAddress.HostToNetworkOrder(long.Parse(input, NumberStyles.HexNumber))
.ToString("X");

As we can not guess what exacly you want as output I let myself write missing possibilities(in code comments)... you can choose which you trully need:
internal class Program
{
private static int ReverseBytes(long val)
{
byte[] intAsBytes = BitConverter.GetBytes(val);
Array.Reverse(intAsBytes);
return BitConverter.ToInt32(intAsBytes, 0);
}
private static string IntToBinaryString(long v)
{
string s = Convert.ToString(v, 2);
string t = s.PadLeft(32, '0');
string res = "";
for (int i = 0; i < t.Length; ++i)
{
if (i > 0 && i%8 == 0)
res += " ";
res += t[i];
}
return res;
}
private static void Main(string[] args)
{
string sValue = "8BABEEF9D2472E65";
long sValueAsInt = long.Parse(sValue, System.Globalization.NumberStyles.HexNumber);
//output {-8382343524677898651}
string sValueAsStringAgain = IntToBinaryString(sValueAsInt);
//output {10001011 10101011 11101110 11111001 11010010 01000111 00101110 01100101}
byte[] data = Encoding.BigEndianUnicode.GetBytes(sValue);
string decodedX = Encoding.BigEndianUnicode.GetString(data);
string retval = data.Aggregate("", (current, b) => current + b.ToString("X2"));
//output {0038004200410042004500450046003900440032003400370032004500360035}
char[] decodedX2 = Encoding.BigEndianUnicode.GetString(data).Reverse().ToArray();
StringBuilder retval2 = new StringBuilder(); //output {56E2742D9FEEBAB8}
foreach (var b in decodedX2)
retval2.Append(b);
Console.ReadLine();
}
}
}
and bout yours Method:
public static string bigToLittle(string data)
{
long sValueAsInt = long.Parse(data, System.Globalization.NumberStyles.HexNumber);
byte[] bytes = BitConverter.GetBytes(sValueAsInt);
string retval = "";
foreach (byte b in bytes)
retval += b.ToString("X2");
return retval; //output {652E47D2F9EEAB8B}
}

I liked #Sebatsian's answer but I ran into issues with the entry being padded by extra zeroes, so I modified it slightly, in case you are doing something like converting Linux VMUUID's in Azure over to standard format. I made use of IPAddress.HostToNetworkOrder, which handles breaking your long into bytes and reversing them.
private string BigToLittle(string data)
{
long sValueAsInt = long.Parse(data, System.Globalization.NumberStyles.HexNumber);
var length = data.Length;
return IPAddress.HostToNetworkOrder(sValueAsInt).ToString("X2").Substring(0, length);
}
In usage:
string uuid = "090556DA-D4FA-764F-A9F1-63614EDA0163";
private string BigToLittle(string data)
{
long sValueAsInt = long.Parse(data, System.Globalization.NumberStyles.HexNumber);
var length = data.Length;
return IPAddress.HostToNetworkOrder(sValueAsInt).ToString("X2").Substring(0, length);
}
var elements = uuid.Split(new char[] { '-' });
var outMe = new List<string> { };
foreach (var item in elements)
{
outMe.Add(BigToLittle(item));
}
var output = String.Join("-", outMe);
//DA560509-FAD4-4F76-F1A9-6301DA4E6163

Byte array to int16 array

Is there a more efficient way to convert byte array to int16 array ?? or is there a way to use Buffer.BlockCopy to copy evry two byte to int16 array ???
public static int[] BYTarrToINT16arr(string fileName)
{
try
{
int bYte = 2;
byte[] buf = File.ReadAllBytes(fileName);
int bufPos = 0;
int[] data = new int[buf.Length/2];
byte[] bt = new byte[bYte];
for (int i = 0; i < buf.Length/2; i++)
{
Array.Copy(buf, bufPos, bt, 0, bYte);
bufPos += bYte;
Array.Reverse(bt);
data[i] = BitConverter.ToInt16(bt, 0);
}
return data;
}
catch
{
return null;
}
}

Use a FileStream and a BinaryReader. Something like this:
var int16List = List<Int16>();
using (var stream = new FileStream(filename, FileMode.Open))
using (var reader = new BinaryReader(stream))
{
try
{
while (true)
int16List.Add(reader.ReadInt16());
}
catch (EndOfStreamException ex)
{
// We've read the whole file
}
}
return int16List.ToArray();
You can also read the whole file into a byte[], and then use a MemoryStream instead of the FileStream if you want.
If you do this then you'll also be able to size the List approrpriately up front and make it a bit more efficient.

Apart from having an off-by-one possibility in case the number of bytes is odd (you'll miss the last byte) your code is OK. You can optimize it by dropping the bt array altogether, swapping i*2 and i*2+1 bytes before calling BitConverter.ToInt16, and passing i*2 as the starting index to the BitConverter.ToInt16 method.

This works if you don't mind using interopservices. I assume it is faster than the other techniques.
using System.Runtime.InteropServices;
public Int16[] Copy_Byte_Buffer_To_Int16_Buffer(byte[] buffer)
{
Int16[] result = new Int16[1];
int size = buffer.Length;
if ((size % 2) != 0)
{
/* Error here */
return result;
}
else
{
result = new Int16[size/2];
IntPtr ptr_src = Marshal.AllocHGlobal (size);
Marshal.Copy (buffer, 0, ptr_src, size);
Marshal.Copy (ptr_src, result, 0, result.Length);
Marshal.FreeHGlobal (ptr_src);
return result;
}
}

var bytes = File.ReadAllBytes(path);
var ints = bytes.TakeWhile((b, i) => i % 2 == 0).Select((b, i) => BitConverter.ToInt16(bytes, i));
if (bytes.Length % 2 == 1)
{
ints = ints.Union(new[] {BitConverter.ToInt16(new byte[] {bytes[bytes.Length - 1], 0}, 0)});
}
return ints.ToArray();

try...
int index = 0;
var my16s = bytes.GroupBy(x => (index++) / 2)
.Select(x => BitConverter.ToInt16(x.Reverse().ToArray(),0)).ToList();

Replace sequence of bytes in binary file

What is the best method to replace sequence of bytes in binary file to the same length of other bytes? The binary files will be pretty large, about 50 mb and should not be loaded at once in memory.
Update: I do not know location of bytes which needs to be replaced, I need to find them first.

Assuming you're trying to replace a known section of the file.
Open a FileStream with read/write access
Seek to the right place
Overwrite existing data
Sample code coming...
public static void ReplaceData(string filename, int position, byte[] data)
{
using (Stream stream = File.Open(filename, FileMode.Open))
{
stream.Position = position;
stream.Write(data, 0, data.Length);
}
}
If you're effectively trying to do a binary version of a string.Replace (e.g. "always replace bytes { 51, 20, 34} with { 20, 35, 15 } then it's rather harder. As a quick description of what you'd do:
Allocate a buffer of at least the size of data you're interested in
Repeatedly read into the buffer, scanning for the data
If you find a match, seek back to the right place (e.g. stream.Position -= buffer.Length - indexWithinBuffer; and overwrite the data
Sounds simple so far... but the tricky bit is if the data starts near the end of the buffer. You need to remember all potential matches and how far you've matched so far, so that if you get a match when you read the next buffer's-worth, you can detect it.
There are probably ways of avoiding this trickiness, but I wouldn't like to try to come up with them offhand :)
EDIT: Okay, I've got an idea which might help...
Keep a buffer which is at least twice as big as you need
Repeatedly:
Copy the second half of the buffer into the first half
Fill the second half of the buffer from the file
Search throughout the whole buffer for the data you're looking for
That way at some point, if the data is present, it will be completely within the buffer.
You'd need to be careful about where the stream was in order to get back to the right place, but I think this should work. It would be trickier if you were trying to find all matches, but at least the first match should be reasonably simple...

My solution :
/// <summary>
/// Copy data from a file to an other, replacing search term, ignoring case.
/// </summary>
/// <param name="originalFile"></param>
/// <param name="outputFile"></param>
/// <param name="searchTerm"></param>
/// <param name="replaceTerm"></param>
private static void ReplaceTextInBinaryFile(string originalFile, string outputFile, string searchTerm, string replaceTerm)
{
byte b;
//UpperCase bytes to search
byte[] searchBytes = Encoding.UTF8.GetBytes(searchTerm.ToUpper());
//LowerCase bytes to search
byte[] searchBytesLower = Encoding.UTF8.GetBytes(searchTerm.ToLower());
//Temporary bytes during found loop
byte[] bytesToAdd = new byte[searchBytes.Length];
//Search length
int searchBytesLength = searchBytes.Length;
//First Upper char
byte searchByte0 = searchBytes[0];
//First Lower char
byte searchByte0Lower = searchBytesLower[0];
//Replace with bytes
byte[] replaceBytes = Encoding.UTF8.GetBytes(replaceTerm);
int counter = 0;
using (FileStream inputStream = File.OpenRead(originalFile)) {
//input length
long srcLength = inputStream.Length;
using (BinaryReader inputReader = new BinaryReader(inputStream)) {
using (FileStream outputStream = File.OpenWrite(outputFile)) {
using (BinaryWriter outputWriter = new BinaryWriter(outputStream)) {
for (int nSrc = 0; nSrc < srcLength; ++nSrc)
//first byte
if ((b = inputReader.ReadByte()) == searchByte0
|| b == searchByte0Lower) {
bytesToAdd[0] = b;
int nSearch = 1;
//next bytes
for (; nSearch < searchBytesLength; ++nSearch)
//get byte, save it and test
if ((b = bytesToAdd[nSearch] = inputReader.ReadByte()) != searchBytes[nSearch]
&& b != searchBytesLower[nSearch]) {
break;//fail
}
//Avoid overflow. No need, in my case, because no chance to see searchTerm at the end.
//else if (nSrc + nSearch >= srcLength)
// break;
if (nSearch == searchBytesLength) {
//success
++counter;
outputWriter.Write(replaceBytes);
nSrc += nSearch - 1;
}
else {
//failed, add saved bytes
outputWriter.Write(bytesToAdd, 0, nSearch + 1);
nSrc += nSearch;
}
}
else
outputWriter.Write(b);
}
}
}
}
Console.WriteLine("ReplaceTextInBinaryFile.counter = " + counter);
}

You can use my BinaryUtility to search and replace one or more bytes without loading the entire file into memory like this:
var searchAndReplace = new List<Tuple<byte[], byte[]>>()
{
Tuple.Create(
BitConverter.GetBytes((UInt32)0xDEADBEEF),
BitConverter.GetBytes((UInt32)0x01234567)),
Tuple.Create(
BitConverter.GetBytes((UInt32)0xAABBCCDD),
BitConverter.GetBytes((UInt16)0xAFFE)),
};
using(var reader =
new BinaryReader(new FileStream(#"C:\temp\data.bin", FileMode.Open)))
{
using(var writer =
new BinaryWriter(new FileStream(#"C:\temp\result.bin", FileMode.Create)))
{
BinaryUtility.Replace(reader, writer, searchAndReplace);
}
}
BinaryUtility code:
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
public static class BinaryUtility
{
public static IEnumerable<byte> GetByteStream(BinaryReader reader)
{
const int bufferSize = 1024;
byte[] buffer;
do
{
buffer = reader.ReadBytes(bufferSize);
foreach (var d in buffer) { yield return d; }
} while (bufferSize == buffer.Length);
}
public static void Replace(BinaryReader reader, BinaryWriter writer, IEnumerable<Tuple<byte[], byte[]>> searchAndReplace)
{
foreach (byte d in Replace(GetByteStream(reader), searchAndReplace)) { writer.Write(d); }
}
public static IEnumerable<byte> Replace(IEnumerable<byte> source, IEnumerable<Tuple<byte[], byte[]>> searchAndReplace)
{
foreach (var s in searchAndReplace)
{
source = Replace(source, s.Item1, s.Item2);
}
return source;
}
public static IEnumerable<byte> Replace(IEnumerable<byte> input, IEnumerable<byte> from, IEnumerable<byte> to)
{
var fromEnumerator = from.GetEnumerator();
fromEnumerator.MoveNext();
int match = 0;
foreach (var data in input)
{
if (data == fromEnumerator.Current)
{
match++;
if (fromEnumerator.MoveNext()) { continue; }
foreach (byte d in to) { yield return d; }
match = 0;
fromEnumerator.Reset();
fromEnumerator.MoveNext();
continue;
}
if (0 != match)
{
foreach (byte d in from.Take(match)) { yield return d; }
match = 0;
fromEnumerator.Reset();
fromEnumerator.MoveNext();
}
yield return data;
}
if (0 != match)
{
foreach (byte d in from.Take(match)) { yield return d; }
}
}
}

public static void BinaryReplace(string sourceFile, byte[] sourceSeq, string targetFile, byte[] targetSeq)
{
FileStream sourceStream = File.OpenRead(sourceFile);
FileStream targetStream = File.Create(targetFile);
try
{
int b;
long foundSeqOffset = -1;
int searchByteCursor = 0;
while ((b=sourceStream.ReadByte()) != -1)
{
if (sourceSeq[searchByteCursor] == b)
{
if (searchByteCursor == sourceSeq.Length - 1)
{
targetStream.Write(targetSeq, 0, targetSeq.Length);
searchByteCursor = 0;
foundSeqOffset = -1;
}
else
{
if (searchByteCursor == 0)
{
foundSeqOffset = sourceStream.Position - 1;
}
++searchByteCursor;
}
}
else
{
if (searchByteCursor == 0)
{
targetStream.WriteByte((byte) b);
}
else
{
targetStream.WriteByte(sourceSeq[0]);
sourceStream.Position = foundSeqOffset + 1;
searchByteCursor = 0;
foundSeqOffset = -1;
}
}
}
}
finally
{
sourceStream.Dispose();
targetStream.Dispose();
}
}