Related
I have a question about interesting thing that happened to me when I have tried to convert elements of List<short> to byte[] in C#.
Firstly, I had to read large binary file, which contains 262144 short type signed numbers. I have read the file and build list of numbers with the following code:
byte[] content = null;
content = File.ReadAllBytes(scanName);
List<int> transformed = new List<int>();
for (int n = 0; n < content.Length; n += 2) // 2 bytes
{
short sample = BitConverter.ToInt16(content, n);
transformed.Add(sample);
}
Then I have compressed and decompressed numbers with algorithm and got back same values, which seemed right. The problems occurs when try to convert both lists to byte arrays. This has been done by following method:
private byte[] ToByte(List<short> list){
List<byte> toRet = new List<byte>();
foreach(short s in list)
{
byte[] converted = BitConverter.GetBytes(s);
foreach(byte b in converted)
{
toRet.Add(b);
}
}
return toRet.ToArray();
}
But when I compared both byte arrays with first.SequenceEqual(second), the method returned false. Isn't it strange, because values in both lists are same?
At the end, I have solved the issue. The problem wasn't in converting short to byte, but in the part of code which hasn't been published there. Specifically, I made very beginner mistake, I converted 2D array into 1D array in the wrong way. Now everything works perfectly. Thank you for all your responses and sorry for inconveniences!
So in c#, I have needed a random below given number generator and I found one on StackOverFlow. But near the end, it converts the byte array into a BigInteger. I tried doing the same, though I am using the Deveel-Math lib as it allows me to us BigDeciamals. But I have tried to the array change into a value, and that into a String but I keep getting a "Could not find any recognizable digits." error and as of now I am stumped.
public static BigInteger RandomIntegerBelow1(BigInteger N)
{
byte[] bytes = N.ToByteArray();
BigInteger R;
Random random = new Random();
do
{
random.NextBytes(bytes);
bytes[bytes.Length - 1] &= (byte)0x7F; //force sign bit to positive
R = BigInteger.Parse(BytesToStringConverted(bytes)) ;
//the Param needs a String value, exp: BigInteger.Parse("100")
} while (R >= N);
return R;
}
static string BytesToStringConverted(byte[] bytes)
{
using (var stream = new MemoryStream(bytes))
{
using (var streamReader = new StreamReader(stream))
{
return streamReader.ReadToEnd();
}
}
}
Deveel-Math
Wrong string conversion
You are converting your byte array to a string of characters based on UTF encoding. I'm pretty sure this is not what you want.
If you want to convert a byte array to a string that contains a number expressed in decimal, try this answer using BitConverter.
if (BitConverter.IsLittleEndian)
Array.Reverse(array); //need the bytes in the reverse order
int value = BitConverter.ToInt32(array, 0);
This is way easier
On the other hand, I notice that Deveel-Math's BigInteger has a constructor that takes a byte array as input (see line 226). So you should be able to greatly simplify your code by doing this:
R = new Deveel.Math.BigInteger(1, bytes) ;
However, since Deveel.Math appears to be BigEndian, you may need to reverse the array first:
System.Array.Reverse(bytes);
R = new Deveel.Math.BigInteger(1, bytes);
I have a Base64 encoded string and I am using the following c# code to decode it. Inside should be a range of Signed integers stored in 16bit.
Now I need to do it in PHP but I'm having real trouble. Can anyone help?
Basically can anyone convert this code to php?
private string decode(string encoded)
{
Byte[] newBytes = Convert.FromBase64String(
encoded.Replace("\n","")
);
int[] newArr = new int[newBytes.Length / 4];
for (int ctr = 0; ctr < newBytes.Length / 4; ctr++)
newArr[ctr] = BitConverter.ToInt16(newBytes, ctr * 4);
return DisplayArray(newArr);
}
private string DisplayArray(Array arr)
{
string output = "";
for (int ctr = 0; ctr < arr.GetUpperBound(0); ctr++)
{
output += arr.GetValue(ctr) + ",";
}
return output;
}
Here is the base64 string....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and it should decode to...
2,0,0,2,2,2,2,2,2,5,5,5,2,0,0,7,5,5,0,0,0,2,5,5,2,2,0,0,0,2,0,2,5,2,2,2,2,5,2,2,5,5,0,5,2,2,0,5,5,0,2,0,2,2,5,7,5,2,0,2,2,2,2,5,5,2,0,2,2,5,0,-2,2,2,0,2,0,5,5,0,2,2,2,0,0,2,2,2,5,2,5,7,5,5,5,7,7,5,7,7,5,7,7,7,5,2,-2,2,2,5,5,2,2,2,7,2,5,5,0,7,2,5,0,2,2,7,5,2,2,2,7,7,7,7,5,2,5,5,5,10,10,7,10,10,10,12,12,12,17,15,20,20,20,22,17,20,20,22,25,27,27,27,32,35,40,40,40,40,40,37,37,37,40,42,37,35,30,35,25,25,20,15,10,7,2,7,5,2,2,0,0,-2,0,2,-2,0,5,2,0,5,0,0,0,-2,0,-2,0,-2,-2,-5,-2,0,-5,-2,-2, etc...
The good
PHP makes it really easy to read in base64 data and convert it to an array of signed integers. Make sure to read up on the unpack function, it's great.
$stringValue = base64_decode($base64data, true);
$integers = unpack("s*", $stringValue);
The bad
That is not what your C# code is doing. After converting the base64 into raw bytes, it then processes that data in chunks of 4 bytes, parsing the first 2 into an int16 and throwing away the second two bytes. Half your data goes down the drain.
The ugly
If the C# code is really the algorithm you are after, here is how to do it in PHP:
$stringValue = base64_decode($base64data, true);
$integers = unpack("s*", $stringValue);
// Throw away half of our data. Because... why not? :)
$integers = array_map('array_shift', array_chunk($integers, 2));
So this is a section of code for my tcp client. This part is to convert the bytes recieved into characters. However, i would like to put some logic to it and to do that i need to set this output to a string. As it keeps printing out every character individually how would i do this? If you require anymore information feel free to ask.
byte[] bb = new byte[100];
int k = stm.Read(bb, 0, 100);
for (int i = 0; i < k; i++)
Console.Write(Convert.ToChar(bb[i]));
Thanks in advace.
As per comments, if you want to decode a byte array in a particular encoding, just use Encoding.GetString. For example:
string text = Encoding.ASCII.GetString(bb, 0, k);
(Note that ASCII is rarely a good choice if the text is meant to be arbitrary human text. UTF-8 is usually a better option at that point, but then you need to bear in mind the possibility that a single character may be split across multiple bytes - and therefore multiple calls to Stream.Read.)
string str = "";
foreach (byte b in bb) str += Convert.ToChar(b);
Console.Write(str);
I have to calculate CRC32 checksum for a string in C# and send it to an external application.
On the other end they will calculate it using Java.
But my checksum does not match on the their end.
e.g. CRC32 checksum of the following string
43HLV109520DAP10072la19z6
is 1269993351 on their end.
And 2947932745 at my end using C#
Please tell me what's going wrong in my code.
I am using this 0xffffffff default seed and following crc table
readonly static uint[] CRCTable = new uint[] {
0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419,
0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4,
0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07,
0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856,
0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3,
0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A,
0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599,
0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190,
0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E,
0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED,
0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3,
0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A,
0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5,
0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010,
0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17,
0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6,
0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615,
0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344,
0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A,
0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1,
0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF,
0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE,
0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31,
0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C,
0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B,
0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1,
0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278,
0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7,
0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66,
0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605,
0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8,
0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B,
0x2D02EF8D
};
CRC32 is calculated over a sequence of bytes and not over a string. So to calculate CRC32 you need to transform the string into bytes first. If you use a different encoding to transform a string to a sequence of bytes the result will be different.
Thus you need to use the same encoding on both sides. I recommend using UTF-8 without BOM.
I have calculated CRC32 with Java and got the same you got in C#. I.e. CRC32(43HLV109520DAP10072la19z6)=2947932745. This means that either they have a bug in java, or you have a bug during transmission.
Code follows.
I suggest you try to send simple data to java application, like zeros or ones, and try to deduce how do they compute CRC.
public static void main(String[] args) {
CRC32 crc32 = new CRC32();
String data = "43HLV109520DAP10072la19z6";
String[] cs = new String[] {"utf8" /*, "cp1252", "cp866" */};
byte[] array;
byte b;
for(int i=0; i<cs.length; ++i) {
array = data.getBytes(Charset.forName(cs[i]));
crc32.reset();
crc32.update(array);
System.out.println(String.format("%s: %d", cs[i], crc32.getValue()));
/*
for(int j=0; j<array.length/2; j++) {
b = array[i];
array[i] = array[array.length-1-i];
array[array.length-1-i] = b;
}
*/
for(int j=0; j<array.length; j+=2) {
b = array[i];
array[i] = array[i+2];
array[i+1] = b;
}
crc32.reset();
crc32.update(array);
System.out.println(String.format("of modified: %d", crc32.getValue()));
}
}
UPDATE
Endiannes reverse also not help
for(int j=0; j<array.length; j+=4) {
b = array[i];
array[i] = array[i+3];
array[i+3] = b;
b = array[i+1];
array[i+1] = array[i+2];
array[i+2] = b;
}
Without delving into any detail, the problem can be related to Java's lack of unsigned integer types. The problem could happen at the int level, but also at the byte level. This is one avenue of investigation.
CRC is calculated over a sequence of bytes and not over a string.
Whichever CRC in java looks different due unavailability of Unsigned int in java.
Convert calculated Int CRC into Hex String and take last 2 Bytes (length 4)
That is your actual CRC unsigned Int.
String hexCrc = Integer.toHexString(crcCalculated);
hexCrc = hexCrc.substring(hexCrc.length()-4);
compare hex CRC of c# and Java both should be same.