my input is this 12 13 13 AF 3F 5f.
I need output the same.
I pass the input through client to server:
byte[] = system.text.encoding.ascii.getbyte(input);
and receive at server side
string some = System.Text.Encoding.ASCII.GetString(output);
but I get excess 0's in the end of the byte almost around 1000's,
how do I trim this 0's with out changing my byte array size
Various options here:
some = some.Substring(0, some.IndexOf('\0') + 1); Or
some = some.Remove(some.IndexOf('\0')); Or
some = some.TrimEnd('\0');
ASCII is 7-bit. Your value AF exceeds 7 bit, try to use UTF8 encoding
Related
Why, when I turn INT value to bytes and to ASCII and back, I get another value?
Example:
var asciiStr = new string(Encoding.ASCII.GetChars(BitConverter.GetBytes(2000)));
var intVal = BitConverter.ToInt32(Encoding.ASCII.GetBytes(asciiStr), 0);
Console.WriteLine(intVal);
// Result: 1855
ASCII is only 7-bit - code points above 127 are unsupported. Unsupported characters are converted to ? per the docs on Encoding.ASCII:
The ASCIIEncoding object that is returned by this property might not have the appropriate behavior for your app. It uses replacement fallback to replace each string that it cannot encode and each byte that it cannot decode with a question mark ("?") character.
So 2000 decimal = D0 07 00 00 hexadecimal (little endian) = [unsupported character] [BEL character] [NUL character] [NUL character] = ? [BEL character] [NUL character] [NUL character] = 3F 07 00 00 hexadecimal (little endian) = 1855 decimal.
TL;DR: Everything's fine. But you're a victim of character replacement.
We start with 2000. Let's acknowledge, first, that this number can be represented in hexadecimal as 0x000007d0.
BitConverter.GetBytes
BitConverter.GetBytes(2000) is an array of 4 bytes, Because 2000 is a 32-bit integer literal. So the 32-bit integer representation, in little endian (least significant byte first), is given by the following byte sequence { 0xd0, 0x07, 0x00, 0x00 }. In decimal, those same bytes are { 208, 7, 0, 0 }
Encoding.ASCII.GetChars
Uh oh! Problem. Here's where things likely took an unexpected turn for you.
You're asking the system to interpret those bytes as ASCII-encoded data. The problem is that ASCII uses codes from 0-127. The byte with value 208 (0xd0) doesn't correspond to any character encodable by ASCII. So what actually happens?
When decoding ASCII, if it encounters a byte that is out of the range 0-127 then it decodes that byte to a replacement character and moves to the next byte. This replacement character is a question mark ?. So the 4 chars you get back from Encoding.ASCII.GetChars are ?, BEL (bell), NUL (null) and NUL (null).
BEL is the ASCII name of the character with code 7, which traditionally elicits a beep when presented on a capable terminal. NUL (code 0) is a null character traditionally used for representing the end of a string.
new string
Now you create a string from that array of chars. In C# a string is perfectly capable of representing a NUL character within the body of a string, so your string will have two NUL chars in it. They can be represented in C# string literals with "\0", in case you want to try that yourself. A C# string literal that represents the string you have would be "?\a\0\0" Did you know that the BEL character can be represented with the escape sequence \a? Many people don't.
Encoding.ASCII.GetBytes
Now you begin the reverse journey. Your string is comprised entirely of characters in the ASCII range. The encoding of a question mark is code 63 (0x3F). And the BEL is 7, and the NUL is 0. so the bytes are { 0x3f, 0x07, 0x00, 0x00 }. Surprised? Well, you're encoding a question mark now where before you provided a 208 (0xd0) byte that was not representable with ASCII encoding.
BitConverter.ToInt32
Converting these four bytes back to a 32-bit integer gives the integer 0x0000073f, which, in decimal, is 1855.
String encoding (ASCII, UTF8, SHIFT_JIS, etc.) is designed to pigeonhole human language into a binary (byte) form. It isn't designed to store arbitrary binary data, such as the binary form of an integer.
While your binary data will be interpreted as a string, some of the information will be lost, meaning that storing binary data in this way will fail in the general case. You can see the point where this fails using the following code:
for (int i = 0; i < 255; ++i)
{
var byteData = new byte[] { (byte)i };
var stringData = System.Text.Encoding.ASCII.GetString(byteData);
var encodedAsBytes = System.Text.Encoding.ASCII.GetBytes(stringData);
Console.WriteLine("{0} vs {1}", i, (int)encodedAsBytes[0]);
}
Try it online
As you can see it starts off well because all of the character codes correspond to ASCII characters, but once we get up in the numbers (i.e. 128 and beyond), we start to require a more than 7 bits to store the binary value. At this point it ceases to be decoded correctly, and we start seeing 63 come back instead of the input value.
Ultimately you will have this problem encoding binary data using any string encoding. You need to choose an encoding method specifically meant for storing binary data as a string.
Two popular methods are:
Hexadecimal
Base64 using ToBase64String and FromBase64String
Hexadecimal example (using the hex methods here):
int initialValue = 2000;
Console.WriteLine(initialValue);
// Convert from int to bytes and then to hex
byte[] bytesValue = BitConverter.GetBytes(initialValue);
string stringValue = ByteArrayToString(bytesValue);
Console.WriteLine("As hex: {0}", stringValue); // outputs D0070000
// Convert form hex to bytes and then to int
byte[] decodedBytesValue = StringToByteArray(stringValue);
int intValue = BitConverter.ToInt32(decodedBytesValue, 0);
Console.WriteLine(intValue);
Try it online
Base64 example:
int initialValue = 2000;
Console.WriteLine(initialValue);
// Convert from int to bytes and then to base64
byte[] bytesValue = BitConverter.GetBytes(initialValue);
string stringValue = Convert.ToBase64String(bytesValue);
Console.WriteLine("As base64: {0}", stringValue); // outputs 0AcAAA==
// Convert form base64 to bytes and then to int
byte[] decodedBytesValue = Convert.FromBase64String(stringValue);
int intValue = BitConverter.ToInt32(decodedBytesValue, 0);
Console.WriteLine(intValue);
Try it online
P.S. If you simply wanted to convert your integer to a string (e.g. "2000") then you can simply use .ToString():
int initialValue = 2000;
string stringValue = initialValue.ToString();
I convert my Hex to dump to get special character like symbol but when I try to convert my "0x18" i "\u0018" this value. Can anyone give me solution regarding this matter.
Here is my code:
public static string FromHexDump(string sText)
{
Int32 lIdx;
string prValue ="" ;
for (lIdx = 1; lIdx < sText.Length; lIdx += 2)
{
string prString = "0x" + Mid(sText, lIdx, 2);
string prUniCode = Convert.ToChar(Convert.ToInt64(prString,16)).ToString();
prValue = prValue + prUniCode;
}
return prValue;
}
I used VB language. I have a database that already encrypted text to my password and the value is BAA37D40186D like this so I loop it by step 2 and it will like this 0xBA,0xA3,0x7D,0x40,0x18,0x6D and the VB result getting like this º£}#m
You can use this code:
var myHex = '\x0633';
var formattedString += string.Format(#"\x{0:x4}", (int)myHex);
Or you can use this code from MSDN (https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/types/how-to-convert-between-hexadecimal-strings-and-numeric-types):
string hexValues = "48 65 6C 6C 6F 20 57 6F 72 6C 64 21";
string[] hexValuesSplit = hexValues.Split(' ');
foreach (string hex in hexValuesSplit)
{
// Convert the number expressed in base-16 to an integer.
int value = Convert.ToInt32(hex, 16);
// Get the character corresponding to the integral value.
string stringValue = Char.ConvertFromUtf32(value);
char charValue = (char)value;
Console.WriteLine("hexadecimal value = {0}, int value = {1}, char value = {2} or {3}",
hex, value, stringValue, charValue);
}
The question is unclear - what is the database column's type? Does it contain 6 bytes, or 12 characters with the hex encoding of the bytes? In any case, this has nothing to do with special characters or encodings.
First, 0x18 is the byte value of the Cancel Character in the Latin 1 codepage, not the pound sign. That's 0xA3. It seems that the byte values in the question are just the Latin 1 bytes for the string in hex.
.NET strings are Unicode (UTF16LE specifically). There's no UTF8 string or Latin1 string. Encodings and codepages apply when converting bytes to strings or vice versa. This is done using the Encoding class and eg Encoding.GetBytes
In this case, this code will convert the byte to the expected string form, including the unprintable character :
new byte[] {0xBA,0xA3,0x7D,0x40,0x18,0x6D};
var latinEncoding=Encoding.GetEncoding(1252);
var result=latinEncoding.GetString(dbBytes);
The result is :
º£}#m
With the Cancel character between # and m.
If the database column contains the byte values as strings :
it takes double the required space and
the hex values have to be converted back to bytes before converting to strings
The x format is used to convert numbers or bytes to their hex form and vice versa. For each byte value, ToString("x") returns the hex string.
The hex string can be produced from the original buffer with :
var dbBytes=new byte[] {0xBA,0xA3,0x7D,0x40,0x18,0x6D};
var hexString=String.Join("",dbBytes.Select(c=>c.ToString("x")));
There are many questions that show how to parse a byte string into a byte array. I'll just steal Jared Parson's LINQ answer :
public static byte[] StringToByteArray(string hex) {
return Enumerable.Range(0, hex.Length)
.Where(x => x % 2 == 0)
.Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
.ToArray();
}
With that, we can parse the hex string into a byte array and convert it to the original string :
var bytes=StringToByteArray(hexString);
var latinEncoding=Encoding.GetEncoding(1252);
var result=latinEncoding.GetString(bytes);
First of all u don't need dump but Unicode, I would recomend to read about unicode/encoding etc and why this is a problem with strings.
PS: solution : StackOverflow
With respect to this tool, I need to convert hexadecimal data, irrespective of their combination to equivalent text. For example:
"HelloWorld" = 48656c6c6f576f726c64;
The solution needs to take into account that hexadecimal can be grouped in different lengths:
48656c6c 6f576f72 6c64
or
48 65 6c 6c 6f 57 6f 72 6c 64
All of the hexadecimal values supplied above read as HelloWorld when converted to text.
First, I would like to point out that this question has been asked many times on the web (here is one example). However, I am going to break this down step by step for you to hopefully teach you how to not only utilize your resources available on the web, but also how to solve your problem.
Overview: Converting from hexadecimal data to text that is able to be read by human beings is a straight-forward process in modern development languages; you clean the data (ensuring no illegal characters remain), then you convert down to the byte level so that you can work with the raw data. Finally, you'll convert that raw data into readable text utilizing a method that has already been created by Microsoft.
Important: Remember, for the conversion to work, you have to ensure you're converting in the same format that you started with:
ASCII -> ASCII: Works Great!
ASCII -> UTF7: Not so much...
Removing Illegal Characters: One of the first things you'll need to do is ensure the hexadecimal value that you're supplying doesn't contain any illegal characters. The simplest way to do this is to create an array of acceptable characters and then remove anything but these in a loop:
private string GetCleanHex(string hex) {
string legalCharacters = "0123456789ABCDEF";
string result = hex.ToUpper();
foreach (char c in result) {
if (!legalCharacters.Contains(c))
result = result.Replace(c.ToString(), string.Empty);
}
}
Getting The Byte Array: Once you've cleaned out all illegal characters, you can now convert your hexadecimal string into a byte array. This is required to convert from hexadecimal to ASCII. This step was provided by the linked post above:
private byte[] GetBytesFromHex(string hex) {
byte[] bytes = new byte[result.Length / 2];
for (int i = 0; i < bytes.Length; i++)
bytes[i] = Convert.ToByte(result.Substring(i * 2, 2), 16);
}
Converting To Text: Now that you've cleaned your data, and converted it to a byte[], you can now convert that byte data into ASCII. This can be done using a method available in Encoding.ASCII called GetString:
string text = Encoding.ASCII.GetString(bytes);
The Final Result: Plug all of this into your application and you'll have successfully converted hexadecimal data into clean, readable text:
string hex = GetCleanHex("506c 65 61736520 72 656164 20686f77 2074 6f 2061 73 6b 2e");
byte[] bytes = GetBytesFromHex(hex);
string text = Encoding.ASCII.GetString(bytes);
Console.WriteLine(text);
Console.ReadKey();
The code above will print the following text to the console:
Please read how to ask.
I've modified an example to send & receive from serial, and that works fine.
The device I'm connecting to has three commands I need to work with.
My experience is with C.
MAP - returns a list of field_names, (decimal) values & (hex) addresses
I can keep track of which values are returned as decimal or hex.
Each line is terminated with CR
:: Example:
MEMBERS:10 - number of (decimal) member names
NAME_LENGTH:15 - (decimal) length of each name string
NAME_BASE:0A34 - 10 c-strings of (15) characters each starting at address (0x0A34) (may have junk following each null terminator)
etc.
GET hexaddr hexbytecount - returns a list of 2-char hex values starting from (hexaddr).
The returned bytes are a mix of bytes/ints/longs, and null terminated c-strings terminated with CR
:: Example::
get 0a34 10 -- will return
0A34< 54 65 73 74 20 4D 65 20 4F 75 74 00 40 D3 23 0B
This happens to be 'Test Me Out'(00) followed by junk
etc.
PUT hexaddr hexbytevalue {{value...} {value...}} sends multiple hex byte values separated by spaces starting at hex address, terminated by CR/LF
These bytes are a mix of bytes/ints/longs, and null terminated c-strings :: Example:
put 0a34 50 75 73 68 - (ascii Push)
Will replace the first 4-chars at 0x0A34 to become 'Push Me Out'
SAVED OK
See my answer previously about serial handling, which might be useful Serial Port Polling and Data handling
to convert your response to actual text :-
var s = "0A34 < 54 65 73 74 20 4D 65 20 4F 75 74 00 40 D3 23 0B";
var hex = s.Substring(s.IndexOf("<") + 1).Trim().Split(new char[] {' '});
var numbers = hex.Select(h => Convert.ToInt32(h, 16)).ToList();
var toText = String.Join("",numbers.TakeWhile(n => n!=0)
.Select(n => Char.ConvertFromUtf32(n)).ToArray());
Console.WriteLine(toText);
which :-
skips through the string till after the < character, then splits the rest into hex string
then, converts each hex string into ints ( base 16 )
then, takes each number till it finds a 0 and converts each number to text (using UTF32 encoding)
then, we join all the converted strings together to recreate the original text
alternatively, more condensed
var hex = s.Substring(s.IndexOf("<") + 1).Trim().Split(new char[] {' '});
var bytes = hex.Select(h => (byte) Convert.ToInt32(h, 16)).TakeWhile(n => n != 0);
var toText = Encoding.ASCII.GetString(bytes.ToArray());
for converting to hex from a number :-
Console.WriteLine(123.ToString("X"));
Console.WriteLine(123.ToString("X4"));
Console.WriteLine(123.ToString("X8"));
Console.WriteLine(123.ToString("x4"));
also you will find playing with hex data is well documented at https://msdn.microsoft.com/en-us/library/bb311038.aspx
I'd like to remove 4 byte UTF8 characters which starts with \xF0 (the char with the ASCII code 0xF0) from a string and tried
sText = Regex.Replace (sText, "\xF0...", "");
This doesn't work. Using two backslashes did not work neither.
The exact input is the content of https://de.wikipedia.org/w/index.php?title=Spezial:Exportieren&action=submit&pages=Unicode The 4 byte character ist the one after the text "[[Violinschlüssel]] ", in hex notation: .. 0x65 0x6c 0x5d 0x5d 0x20 0xf0 0x9d 0x84 0x9e 0x20 .. The expected output is 0x65 0x6c 0x5d 0x5d 0x20 0x20 ..
What's wrong?
Such characters will be surrogate pairs in .NET which uses UTF-16. Each of them will be two UTF-16 code units, that is two char values.
To just remove them, you can do (using System.Linq;):
sText = string.Concat(sText.Where(x => !char.IsSurrogate(x)));
(uses an overload of Concat introduced in .NET 4.0 (Visual Studio 2010)).
Late addition: It may give better performance to use:
sText = new string(sText.Where(x => !char.IsSurrogate(x)).ToArray());
even if it looks worse. (Works in .NET 3.5 (Visual Studio 2008).)
You are trying to search for byte values but C# strings are made from char values. The C# language spec at section "2.4.4.4 Character literals" states:
A character literal represents a single character, and usually consists of a character in quotes, as in 'a'.
...
A hexadecimal escape sequence represents a single Unicode character, with the value formed by the hexadecimal number following \x.
Hence the search for "\xF0..." is searching for the character U+F0 which would be represented by the bytes C3 B0.
If you want find replace all Unicode characters whose first byte is 0xF0 then I believe you need to search for the character values whose first byte if 0xFO.
The character U+10000 is represented as F0 90 80 80 (the preceding code is U+FFFF which is EF BF BF). The first code with F1 .... .. is U+40000 which is F1 80 80 80 and the value before it is U+3FFFF which is F0 BF BF BF.
Hence you need to remove characters in the range U+10000 to U+3FFFF. This should be possible with a regular expression such as
sText = Regex.Replace (sText, "[\\x10000-\\x3FFFF]", "");
The relevant characters from the source quoted in the question have been extracted into the code below. The code then tries to understand how the characters are held in strings.
static void Main(string[] args)
{
string input = "] 𝄞 (";
Console.Write("Input length {0} : '{1}' : ", input.Length, input);
foreach (char cc in input)
{
Console.Write(" {0,2:X02}", (int)cc);
}
Console.WriteLine();
}
The output from the program is as below. This supports the surrogate pair explanation given by #Jeppe in his answer.
Input length 6 : '] ?? (' : 5D 20 D834 DD1E 20 28