Develop Reference

Sharing array memoryfile C++ to C#

i trying share a array via memoryfile c++ to c# based on this example:stream data from c++ to c# over shared memory.
work fine, but i just can get until position 3 from array, another position come 0.
C++ that creat MemoryFile
#include <windows.h>
#include <stdio.h>
struct Pair {
int length;
int data[10];
};
struct Pair* p;
HANDLE handle;
int dataSend[10]{ 500,33,44,66,2,55,98,7,52,36 };
bool startShare()
{
try
{
handle = CreateFileMappingW(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, sizeof(Pair), L"DataSend");
p = (struct Pair*) MapViewOfFile(handle, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, sizeof(Pair));
return true;
}
catch (...)
{
return false;
}
}
int main()
{
if (startShare() == true)
{
printf("Memory Create");
while (true)
{
if (p != 0) {
for (int h = 0; h < 10; h++)
{
p->data[h] = dataSend[h];
printf("\n number %d", dataSend[h]);
}
}
else
puts("create shared memory error");
}
}
if (handle != NULL)
CloseHandle(handle);
return 0;
}
my C# Read
public static int[] data = new int[10];
public static MemoryMappedFile mmf;
public static MemoryMappedViewStream mmfvs;
static public bool MemOpen()
{
try
{
mmf = MemoryMappedFile.OpenExisting("DataSend");
mmfvs = mmf.CreateViewStream();
return true;
}
catch
{
return false;
}
}
public static void Main(string[] args)
{
while (true)
{
if (MemOpen())
{
byte[] blen = new byte[4];
mmfvs.Read(blen, 0, 4);
byte[] bPosition = new byte[280];
mmfvs.Read(bPosition, 0, 280);
Buffer.BlockCopy(bPosition, 0, data, 0, bPosition.Length);
for (int i = 0; i < data.Length; i++)
{
Console.WriteLine(data[i]);
}
}
}
}
work fine, but i just can get until position 3 from array, another position come 0.
Update, code work fine now
Just a detail,i return a array hex value example:52A7E600
but in my code c# get bit numbers like: 10300071984, how i cant convert in side c# to get same format?

to convert long value to hex in c# you could use:
long intValue = 10300071984;
// Convert long value 10300071984 -> 265EEA030 as a hex in a string variable
string hexValue = intValue.ToString("X");

is there any equivalient php hash crc32b method in c#?

In PHP
echo hash("crc32b","hello world");
//it print : 0d4a1185
Is there any equivalent method in c#?

bellow the class used in one of my c# projects :
class CRC32B
{
public static int Main(String INPUT)
{
// first convert string to byte-array
String input = INPUT;
byte[] bytes = new byte[input.Length * sizeof(char)];
System.Buffer.BlockCopy(input.ToCharArray(), 0, bytes, 0, bytes.Length);
// then calculate the value
int crcVal = (int)crc32(input);
if (crcVal < 0)
{
crcVal = crcVal * (-1);
}
//Console.WriteLine((int)crcVal);
return (int)crcVal;
}
public static uint crc32(string input)
{
var table = 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
};
unchecked
{
uint crc = (uint)(((uint)0) ^ (1));
var len = input.Length;
for (var i = 0; i < len; i++)
{
crc = (crc >> 8) ^ table[
(crc ^ (byte)input[i]) & 0xFF
];
}
//crc = (uint)(crc ^ (-1));
if (crc < 0)
{
crc += (uint)4294967296;
crc = (uint)(crc ^ (-1));
}
return crc;
}
}
}

Received buffer of tcpclient contains not what expected

I have a server side app written in C
struct recv_packet
{
int magic;
int code;
int length;
char *body;
};
char send_buff[1024+1] = "";
ZeroMemory(&send_buff, 1024);
memset(send_buff, 'A', 1024);
//send_buff[1024] = '\0';
recv_packet rcv_pkt = { 0 };
rcv_pkt.magic = MAGIC;
rcv_pkt.code = 0;
rcv_pkt.length = strlen(send_buff);
rcv_pkt.body = send_buff;
int size = sizeof(rcv_pkt.magic) + sizeof(rcv_pkt.code) + sizeof(rcv_pkt.length) + 1024+1;
if (send(ClientSocket, (char *)&rcv_pkt, size, 0) == SOCKET_ERROR)
{
printf("Error %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
On the other side i grab this packet like this:
public struct recv_packet
{
public int magic;
public int code;
public int length;
public byte[] body;
};
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
int port = 4000;
TcpClient client = new TcpClient("127.0.0.1", 4000);
NetworkStream nws = client.GetStream();
BinaryWriter bw = new BinaryWriter(nws);
BinaryReader br = new BinaryReader(nws);
byte[] buff = new byte[512];
send_packet pkt = new send_packet();
pkt.magic = magic;
pkt.cmd = (int)command.MOVE_MOUSE;
while (true)
{
bw.Write(pkt.magic);
bw.Write(pkt.cmd);
//br.Read(buff, 0, 512);
recv_packet rcv_pkt = new recv_packet();
rcv_pkt.magic = br.ReadInt32();
rcv_pkt.code = br.ReadInt32();
rcv_pkt.length = br.ReadInt32();
rcv_pkt.body = br.ReadBytes(rcv_pkt.length);
//string str = rcv_pkt.length.ToString();
string str = System.Text.Encoding.Default.GetString(rcv_pkt.body);
MessageBox.Show(str);
}
}
So it suppose that body will have only '65', but instead I've got some trash in it.
Why could this happen? Thank you for your time.

As I understood there are few ways of resolving this problem - one of them is to redecrlare struct a little bit and then creare a buffer, where all structure elements will be fitted one-by-one. So the solution looks like this:
char send_buff[1024+1] = "";
ZeroMemory(&send_buff, 1025);
memset(send_buff, 'A', 1024);
recv_packet *rcv_pkt = (recv_packet *)malloc(sizeof(recv_packet)+1024+1);
//recv_packet rcv_pkt = { 0 };
rcv_pkt->magic = MAGIC;
rcv_pkt->code = 0;
rcv_pkt->length = strlen(send_buff);
memcpy(rcv_pkt->body, send_buff, 1025);
int size = sizeof(rcv_pkt->magic) + sizeof(rcv_pkt->code) + sizeof(rcv_pkt->length) + 1024 + 1;
//printf("%d", size);
//getchar();
//return 0;
//if (send(ClientSocket, rcv_pkt.body, rcv_pkt.length, 0) == SOCKET_ERROR)
if (send(ClientSocket, (char *)rcv_pkt, size, 0) == SOCKET_ERROR)

C# equalent to perl `pack("v",value)` while packing some values into `byte[]`

I am trying to replicate behavior of a perl script in my c# code. When we convert any value into the Byte[] it should look same irrespective of the language used. SO
I have this function call which looks like this in perl:
$diag_cmd = pack("V", length($s_part)) . $s_part;
where $s_par is defined in following function. It is taking the .pds file at the location C:\Users\c_desaik\Desktop\DIAG\PwrDB\offtarget\data\get_8084_gpio.pds
$s_part =
sub read_pds
{
my $bin_s;
my $input_pds_file = $_[0];
open(my $fh, '<', $input_pds_file) or die "cannot open file $input_pds_file";
{
local $/;
$bin_s = <$fh>;
}
close($fh);
return $bin_s;
}
My best guess is that this function is reading the .pds file and turning it into a Byte array.
Now, I tried to replicate the behavior into c# code like following
static byte[] ConstructPacket()
{
List<byte> retval = new List<byte>();
retval.AddRange(System.IO.File.ReadAllBytes(#"C:\Users\c_desaik\Desktop\DIAG\PwrDB\offtarget\data\get_8084_gpio.pds"));
return retval.ToArray();
}
But the resulting byte array does not look same. Is there any special mechanism that I have to follow to replicate the behavior of pack("V", length($s_part)) . $s_part ?

As Simon Whitehead mentioned the template character V tells pack to pack your values into unsigned long (32-bit) integers (in little endian order). So you need to convert your bytes to a list (or array) of unsigned integers.
For example:
static uint[] UnpackUint32(string filename)
{
var retval = new List<uint>();
using (var filestream = System.IO.File.Open(filename, System.IO.FileMode.Open))
{
using (var binaryStream = new System.IO.BinaryReader(filestream))
{
var pos = 0;
while (pos < binaryStream.BaseStream.Length)
{
retval.Add(binaryStream.ReadUInt32());
pos += 4;
}
}
}
return retval.ToArray();
}
And call this function:
var list = UnpackUint32(#"C:\Users\c_desaik\Desktop\DIAG\PwrDB\offtarget\data\get_8084_gpio.pds");
Update
If you wanna read one length-prefixed string or a list of them, you can use this function:
private string[] UnpackStrings(string filename)
{
var retval = new List<string>();
using (var filestream = System.IO.File.Open(filename, System.IO.FileMode.Open))
{
using (var binaryStream = new System.IO.BinaryReader(filestream))
{
var pos = 0;
while ((pos + 4) <= binaryStream.BaseStream.Length)
{
// read the length of the string
var len = binaryStream.ReadUInt32();
// read the bytes of the string
var byteArr = binaryStream.ReadBytes((int) len);
// cast this bytes to a char and append them to a stringbuilder
var sb = new StringBuilder();
foreach (var b in byteArr)
sb.Append((char)b);
// add the new string to our collection of strings
retval.Add(sb.ToString());
// calculate start position of next value
pos += 4 + (int) len;
}
}
}
return retval.ToArray();
}

pack("V", length($s_part)) . $s_part
which can also be written as
pack("V/a*", $s_part)
creates a length-prefixed string. The length is stored as a 32-bit unsigned little-endian number.
+----------+----------+----------+----------+-------- ...
| Length | Length | Length | Length | Bytes
| ( 7.. 0) | (15.. 8) | (23..16) | (31..24) |
+----------+----------+----------+----------+-------- ...
This is how you recreate the original string from the bytes:
Read 4 bytes
If using a machine other than a little-endian machine,
Rearrange the bytes into the native order.
Cast those bytes into an 32-bit unsigned integer.
Read a number of bytes equal to that number.
Convert that sequences of bytes into a string.
Some languages provide tools that perform more than one of these steps.
I don't know C#, so I can't write the code for you, but I can give you an example in two other languages.
In Perl, this would be written as follows:
sub read_bytes {
my ($fh, $num_bytes_to_read) = #_;
my $buf = '';
while ($num_bytes_to_read) {
my $num_bytes_read = read($fh, $buf, $num_bytes_to_read, length($buf));
if (!$num_bytes_read) {
die "$!\n" if !defined($num_bytes_read);
die "Premature EOF\n";
}
$num_bytes_to_read -= $num_bytes_read;
}
return $buf;
}
sub read_uint32le { unpack('V', read_bytes($_[0], 4)) }
sub read_pstr { read_bytes($_[0], read_uint32le($_[0])) }
my $str = read_pstr($fh);
In C,
int read_bytes(FILE* fh, void* buf, size_t num_bytes_to_read) {
while (num_bytes_to_read) {
size_t num_bytes_read = fread(buf, 1, num_bytes_to_read, fh);
if (!num_bytes_read)
return 0;
num_bytes_to_read -= num_bytes_read;
buf += num_bytes_read;
}
return 1;
}
int read_uint32le(FILE* fh, uint32_t* p_i) {
int ok = read_bytes(fh, p_i, sizeof(*p_i));
if (!ok)
return 0;
{ /* Rearrange bytes on non-LE machines */
const char* p = (char*)p_i;
*p_i = ((((p[3] << 8) | p[2]) << 8) | p[1]) << 8) | p[0];
}
return 1;
}
char* read_pstr(FILE* fh) {
uint32_t len;
char* buf = NULL;
int ok;
ok = read_uint32le(fh, &len);
if (!ok)
goto ERROR;
buf = malloc(len+1);
if (!buf)
goto ERROR;
ok = read_bytes(fh, buf, len);
if (!ok)
goto ERROR;
buf[len] = '\0';
return buf;
ERROR:
if (p)
free(p);
return NULL;
}
char* str = read_pstr(fh);

CRC16 ISO 13239 Implementation

i'm trying to implement Crc16 in C#. I already tried many different implementations, but most of them gives me different values. Here are some of the codes that i already used.
private static int POLYNOMIAL = 0x8408;
private static int PRESET_VALUE = 0xFFFF;
public static int crc16(byte[] data)
{
int current_crc_value = PRESET_VALUE;
for (int i = 0; i < data.Length; i++)
{
current_crc_value ^= data[i] & 0xFF;
for (int j = 0; j < 8; j++)
{
if ((current_crc_value & 1) != 0)
{
current_crc_value = (current_crc_value >> 1) ^ POLYNOMIAL;
}
else
{
current_crc_value = current_crc_value >> 1;
}
}
}
current_crc_value = ~current_crc_value;
return current_crc_value & 0xFFFF;
}
this is the another implementation that i used but both gives different values
const ushort polynomial = 0xA001;
ushort[] table = new ushort[256];
public ushort ComputeChecksum(byte[] bytes)
{
ushort crc = 0;
for (int i = 0; i < bytes.Length; ++i)
{
byte index = (byte)(crc ^ bytes[i]);
crc = (ushort)((crc >> 8) ^ table[index]);
}
return crc;
}
public byte[] ComputeChecksumBytes(byte[] bytes)
{
ushort crc = ComputeChecksum(bytes);
return BitConverter.GetBytes(crc);
}
public Crc16()
{
ushort value;
ushort temp;
for (ushort i = 0; i < table.Length; ++i)
{
value = 0;
temp = i;
for (byte j = 0; j < 8; ++j)
{
if (((value ^ temp) & 0x0001) != 0)
{
value = (ushort)((value >> 1) ^ polynomial);
}
else
{
value >>= 1;
}
temp >>= 1;
}
table[i] = value;
}
}
The value I`m using is an Octet String "[jp3]TEST [fl]Flashing[/fl]" and its expected value is 95F9 in hex. This is an example on the guide of NTCIP protocol
Thanks

This:
static readonly ushort[] fcstab = new ushort[] {
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};
static ushort compute_fcs(byte[] data)
{
return compute_fcs(data, 0, data.Length);
}
static ushort compute_fcs(byte[] data, int start, int length)
{
ushort fcs = 0xFFFF;
int end = start + length;
for (int i = start; i < end; i++)
{
fcs = (ushort)(((ushort)(fcs >> 8)) ^ fcstab[(fcs ^ data[i]) & 0xFF]);
}
return (ushort)(~fcs);
}
static void Main(string[] args)
{
byte[] pattern = new byte[] { 0x02, 0x07, 0x01, 0x03, 0x01, 0x02, 0x00, 0x34, 0x07, 0x07, 0x1C, 0x59, 0x34, 0x6F, 0xE1, 0x83, 0x00, 0x00, 0x41, 0x06, 0x06, 0x7B, 0x3C, 0xFF, 0xCF, 0x3C, 0xC0 };
// http://www.ite.org/standards/1203v03-04%20Part%201%20dms2011.pdf
// Page 158, CRC = 0x52ED
ushort fcs = compute_fcs(pattern); // 0x52ED
}
will work for the only test given here http://www.ite.org/standards/1203v03-04%20Part%201%20dms2011.pdf (around page 158, CRC = 0x52ED).
For the string example of the PDF, as written some pages later:
" Indicates the CRC-16 (polynomial defined in ISO/IEC 3309) value
created using the values of the dmsMessageMultiString (MULTI-Message), the
dmsMessageBeacon, and the dmsMessagePixelService objects in the order listed,
not including the OER type or length fields. Note that the calculation shall
assume a value of zero (0) for the dmsMessageBeacon object and/or for the
dmsMessagePixelService object if they are not supported
(emphasis added)
so:
string str = "[jp3]TEST [fl]Flashing[/fl]";
var bytes = Encoding.ASCII.GetBytes(str);
Array.Resize(ref bytes, bytes.Length + 2);
// Note that these two rows are useless, because the Array.Resize will have already filled with 0
bytes[bytes.Length - 2] = 0; // dmsMessageBeacon
bytes[bytes.Length - 1] = 0; // dmsMessagePixelService
ushort fcs2 = compute_fcs(bytes); // 0xF995
var bytes2 = BitConverter.GetBytes(fcs2); // 0x95 0xF9
This shows that the protocol is little endian (as my PC, that is an Intel). In fact the CRC-16 of the string is 0xF995, but these 16 bits in memory appear as 0x95 0xF9 (as in the example, that shows the single bytes).

There are many algorithms of CRC-16 calculation.
For instance:
CRC-16-IBM which used in Modbus protocol, USB etc. is most popular.
CRC-16-CCITT used in Bluetooth.
I use CRC-16-IBM in my applications which work with industrial controllers.
public static UInt16 FastCRC16(byte[] Buffer, UInt16 ui_length)
{
UInt16[] crc_table = {
0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040};
UInt16 Crc = 65535;
UInt16 x;
for (UInt16 i = 0; i < ui_length; i++)
{
x = (UInt16)(Crc ^ Buffer[i]);
Crc = (UInt16)((Crc >> 8) ^ crc_table[x & 0x00FF]);
}
return Crc;
}