Develop Reference

Reading UTF8 file, gives diamond with question mark on unknown characters

I have a file I am reading from to acquire a database of music files, like this;
00 6F 74 72 6B 00 00 02 57 74 74 79 70 00 00 00 .otrk...Wttyp...
06 00 6D 00 70 00 33 70 66 69 6C 00 00 00 98 00 ..m.p.3pfil...~.
44 00 69............. D.i.....
Etc., there could be hundreds to thousands of records in this file, all split at "otrk" into a string this is the start of a new track.
The problem actually lies in the above, all the tracks start with otrk, and the has field identifiers, their length, and value, for example above;
ttyp = type, and 06 following it is the length of the value, which is .m.p.3 or 00 6D 00 70 00 33
then the next field identifier is pfil = filename, this lies the issue, specifically the length, which value is 98, however when read into a string becomes unrecognizable and defaults to a diamond with a question mark, and a value of 239, which is wrong. How can I avoid this and get the correct value in order to display the value correctly.
My code to read the file;
db_file = File.ReadAllText(filePath, Encoding.UTF8);
and the code to split and sort through the file
string[] entries = content.Split(new string[] "otrk", StringSplitOptions.None);
public List<Songs> Songs { get; } = new List<Songs>();
foreach(string entry in entries)
{
Songs.Add(Song.Create(entry));
}
Song.Create looks like;
public static Song Create(string dbString)
{
Song toRet = new Song();
for (int farthestReached = 0; farthestReached < dbString.Length;)
{
int startOfString = -1;
int iLength = -1;
byte[] b = Encoding.UTF8.GetBytes("0");
//Gets the start index
foreach(var l in labels)
{
startOfString = dbString.IndexOf(l, farthestReached);
if (startOfString >= 0)
{
// get identifer index plus its length
iLength = startOfString + 3;
var valueIndex = iLength + 5;
// get length of value
string temp = dbString.Substring(iLength + 4, 1);
b = Encoding.UTF8.GetBytes(temp);
int xLen = b[0];
// populate the label
string fieldLabel = dbString.Substring(startOfString, l.Length);
// populate the value
string fieldValue = dbString.Substring(valueIndex, xLen);
// set new
farthestReached = xLen + valueIndex;
switch (fieldLabel[0])
{
case 'p':
case 't':
string stringValue = "";
foreach (char c in fieldValue)
{
if (c == 0)
continue;
stringValue += c;
}
assignStringField(toRet, fieldLabel, stringValue);
break;
}
break;
}
}
//If a field was not found, there are no more fields
if (startOfString == -1)
break;
}
return toRet;
}

The file is not a UTF-8 file. The hex dump shown in the question makes it clear that it is not a UTF-8 file, and neither a proper text file in any other text encoding. It rather looks like some binary (serialized) format, with data fields of different types.
You cannot reliably read a binary file naively like a text file, especially considering that certain UTF-8 characters are represented by two or more bytes. Thus, it is pretty likely that the UTF-8 decoder will get confused by all the binary data and might miss the first character(s) of a text field because preceding (binary) byte not belonging to a text field could coincidentally be equal to a start byte of a multi-byte character sequence in UTF-8, thus accidentally not correctly identifying the first character(s) in a text field because the UTF-8 decoder is trying to decode a multi-byte sequence not aligning with the text field.
Not only that, but certain byte values or byte sequences are not valid UTF-8 encodings for character, and you would "lose" such bytes when trying to read them as UTF-8 text.
Also, since it is possible for byte sequences of multiple bytes to form a single UTF-8 character, you cannot rely on every individual byte being turned into a character with the same ordinal value (even if the byte value might be a valid ASCII value), since such a byte could be decoded "merely" as part of a UTF-8 byte sequence into a single character whose ordinal value is entirely different from the value of the bytes in such a byte sequence.
That said, as far as i can tell, the text field in your litte data snippet above does not look like UTF-8 at all. 00 6D 00 70 00 33 (*m*p*3) and 00 44 00 69 (*D*i) are definitely not UTF-8 -- note the zero bytes.
Thus, first consult the file format specification to figure out the actual text encoding used for the text fields in this file format. Don't guess. Don't assume. Don't believe. Look up, verify and confirm.
Secondly, since the file is not a proper text file (as already mentioned), you cannot read it like a text file with File.ReadAllText. Instead, read the raw byte data, for example with File.ReadAllBytes.
Find the otrk marker in the byte data of the file not as text, but by the 4 byte values this marker is made of.
Then, parse the byte data following the otrk marker according to the file format specification, and only decode the bytes that are actual text data into strings, using the correct text encoding as denoted by the file format specification.

Arduino serial communication working strange

I am writing a C# program that has to communicate with an Arduino. Basically it sends data to it and I should be able to read in the serial monitor.
C# code:
if (errCheck[i].IsChecked.GetValueOrDefault() == true)
err = "1"+err;
else
err = "0"+err;
_serialPort.Write("<16,"+ Convert.ToUInt32(err,2) + ">");
Arduino code:
void parseData() { // split the data into its parts
char * strtokIndx; // this is used by strtok() as an index
//strtokIndx = strtok(tempChars,","); // get the first part - the string
//strcpy(messageFromPC, strtokIndx); // copy it to messageFromPC
strtokIndx = strtok(tempChars, ","); // this continues where the previous call left off
integerFromPC = atoi(strtokIndx); // convert this part to an integer
switch (integerFromPC) {
//all cases
case 16: //managing errors
delay(10);
strtokIndx = strtok(NULL, ",");
uint32_tFromPC = atoi(strtokIndx);
errors=uint32_tFromPC;
Serial.print("errors Updated" );
When the last checkbox is checked (so my binary string is 1 and 31 0's) the serial monitor reads 7F FF FF FF instead of 80 00 00 00.
I have tried using ulong but it doesn't seem to work either, any ideas?

Why do you want to convert the String to int32 and then back to String??
Simply do this:
if (errCheck[i].IsChecked.GetValueOrDefault() == true)
err = "1"+err;
else
err = "0"+err;
_serialPort.Write("<16,"+ err + ">");
Even Uint32 can't take 32 digits!
And in your arduino code you are using atoi too. Handle it as a String. Why do u need it as a integer?
Btw thing about using enums for bitwise operations for examples look here:
http://www.alanzucconi.com/2015/07/26/enum-flags-and-bitwise-operators/

parse hex incoming / create outgoing strings

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

C# Programming How to grep columns/lines from Text File?

I have a C# console program which main functions should let a user grep lines / columns from a log text file.
An Example within the text file the user wishes to grep a group of all the related lines starting from a particular date etc. "Tue Aug 03 2004 22:58:34" to "Wed Aug 04 2004 00:56:48". Therefore after processing, the program would then output all the data found within the log text files between the 2 dates.
Could someone please advise on some codes that I could use to grep or create a filter to retrieve the neccessary text/data from the file? Thanks!
C# Program Files:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.IO;
namespace Testing
{
class Analysis
{
static void Main()
{
// Read the file lines into a string array.
string[] lines = System.IO.File.ReadAllLines(#"C:\Test\ntfs.txt");
System.Console.WriteLine("Analyzing ntfs.txt:");
foreach (string line in lines)
{
Console.WriteLine("\t" + line);
// ***Trying to filter/grep out dates, file size, etc****
if (lines = "Sun Nov 19 2000")
{
Console.WriteLine("Print entire line");
}
}
// Keep the console window open in debug mode.
Console.WriteLine("Press any key to exit.");
System.Console.ReadKey();
}
}
}
Log Text File Example:
Wed Jul 21 2004 16:58:48 499712 m... r/rrwxrwxrwx 0 0 8360-128-3
C:/Program Files/AccessData/Common Files/AccessData LicenseManager/LicenseManager.exe
Tue Aug 03 2004 22:58:34 23040 m... r/rrwxrwxrwx 0 0 8522-128-3
C:/System Volume Information/_restore{88D7369F-4F7E-44D4-8CD1-
F7FF1F6AC067}/RP4/A0002101.sys
23040 m... r/rrwxrwxrwx 0 0 9132-128-3
C:/WINDOWS/system32/ReinstallBackups/0003/DriverFiles/i386/mouclass.sys
23040 m... r/rrwxrwxrwx 0 0 9135-128-4 C:/System Volume
Information/_restore{88D7369F-4F7E-44D4-8CD1-F7FF1F6AC067}/RP4/A0003123.sys
23040 m... r/rrwxrwxrwx 0 0 9136-128-3
C:/WINDOWS/system32/drivers/mouclass.sys
Tue Aug 03 2004 23:01:16 196864 m... r/rrwxrwxrwx 0 0 4706-128-3
C:/WINDOWS/system32/drivers/rdpdr.sys
Tue Aug 03 2004 23:08:18 24960 m... r/rrwxrwxrwx 0 0 8690-128-3
C:/WINDOWS/system32/drivers/hidparse.sys

You could do this using Regex to select matching lines in a richer way than string.Contains allows.
Not sure why you are reinventing findstr.exe though.
For large files you might find File.ReadLines (.Net 4 only) performs better - this reads the same lines but allows you to process them in a foreach and other IEnumerable scenarios without loading the entire file into RAM at once.

Well, as a quick fix for the specific example:
if (line.StartsWith("Sun Nov 19 2000"))
{
Console.WriteLine(line);
}
You could use Contains to find a substring within the line.
Note that loading the whole file in an array won't scale well for very large logs. We can look into fixing that if it's an issue for you - but let's take things slowly :)

Here's a grep style method I use in testing:
public static List<string> FileGrep(string filePath, string searchText)
{
var matches = new List<string>();
using (var f = File.OpenRead(filePath))
{
var s = new StreamReader(f);
while (!s.EndOfStream)
{
var line = s.ReadLine();
if (line != null && line.Contains(searchText)) matches.Add(line);
}
f.Close();
}
return matches;
}

Read .dat file in c#

i want to read a .dat file that have following conditions:-
First name offset 21
First name format ASCIIz 15 chars + \0
Middle initials offset 37
ID offset -8
ID format/length Unsigned int (4 bytes)
so help me for sorting this issue in c#.
Thanks in advance.
Gurpreet
.dat file
( ÿ / rE ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ XÙþÞ¦d e e Mr. Sam Ascott Sam 9209 Sandpiper Lane 21204 410 5558987 410 5556700 275 MM229399098 (¬ Þ e ܤ•Þ„ œÔ£ÝáØáØ ’Þ[Þ €–˜ ä–˜ [Þ ¶ Norman Eaton Friend of Dr. Shultz Removal of #1,16,17 & 32 öÜÝ)Ý Ä d 01 21 21 21 e 101 22099 XÙþÞ¦d e . Mrs. Patty Baxter Patty 3838 Tommytrue Court 21234 410 2929290 410 3929209 FM218798127 HAY FEVER Þ . „¤¢Þè   _ÐÍÝBÒBÒ ’ÞÝ €–˜ ä–˜ ÍÝ f Joanne Abbey

Here is a tutorial how to use BinaryReader for this purpose:
http://dotnetperls.com/binaryreader

You can use Jet OleDB to query .dat files:
var query = "select * from file.dat";
var connection = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\file.dat;Extended Properties=\"text;HDR=NO;FMT=FixedLength\"");
See this link:
Code Project. Read Text File (txt, csv, log, tab, fixed length)
And check these:
Reading a sequential-access file
DAT files in C#
Read a file in C#
BinaryReader Class
Jon Skeet. Reading binary data in C#

As said, have a look at the BinaryReader
//Example...
BinaryReader reader = new BinaryReader(stream);
string name = Encoding.ASCII.GetString(reader.ReadBytes(8));
int number = reader.ReadInt32();

my .dat file content - " €U§µ­PÕ „ÕG¬u "
click here to see the content of my .dat file in Notepad and hexa editor
string fileName = #"W:\yourfilename.dat";
//Read the binary file as byte array
byte[] bHex = File.ReadAllBytes(fileName);
//Create string builder for extracting the HEX values
StringBuilder st = new StringBuilder();
//initialize the int for 0
int i = 0;
// check it worked
//Reverse the HEX array for readability
foreach (char c in bHex.Reverse())
{
i++;
// 12 to 21 byte in the reverse order for interseted value in ticks"
if (i > 12 && i < 21)
st.Append(Convert.ToInt32(c).ToString("X2"));
}
// Convert HEX to Deciamal
long Output = Convert.ToInt64(st.ToString(), 16);
//Convert ticks to date time
DateTime dt = new DateTime(Output);
//Write the output date to console
Console.Write(dt);
Final de-crypt binary content to data-time.
final output of the program