Find Values between two prefixes and swap one for the other

Question

I’m developing an application where you have to find a definite value and literally walk 19 houses.

130000007363645C7363645F
6178747265653030311300000073
6363645F6178747265653030315F

• Search for value from: 13000000
• Floor of: 13000000 until: 7363645C736363645F6178746565303031 (Or until you find another value 13)

Thus remaining:

130000007363645C7363645F
61787472653030311300000073
6363645F6178747265653030315F

• Look for another value: 13000000

Thus remaining:

13000000736363645C736363645F
61787472653030311300000073
6363645F6178747265653030315F

• Walk of new value : 13000000 up to the other value: 736363645F6178747265653030315F

Thus remaining:

13000000736363645C736363645F
6178747265653030311300000073
6363645F6178747265653030315F

Then exchange one value for another: 7363645C7363645F
617874726530303 for 736363645F6178747265653030315F

Making a loop repeating the same function throughout the file.

=======================@Edit

Thus:

13-00-00-00-73-63-63-64-5C-73-63-63-64-5F-61-78-74-72-65-65-30-30-31-13-00-00-00-73-63-63-64-5F-61-78-74-72-65-65-30-30-31-5F

Thus remaining:

13-00-00-00-73-63-63-64-5F-61-78-74-72-65-65-30-30-31-5F -13-00-00-00-73-63-63-64-5C-73-63-63-64-5F-61-78-74-72-65-65-30-30-31

NOTE: I changed the top value after the "13-00-00-00" down

============================@ I tried something similar to that:

byte[] file = File.ReadAllBytes(file);

string hexStrings = BitConverter.ToString(file);

hexStrings = hexStrings.Replace("-", "");

foreach (byte hexString in hexStrings)
{
}

Answer 1

A simple way is by regular expression, using Regex:

using System.Text.RegularExpressions;

var padrao = @"13-00-00-00-(([0-9a-fA-F]{2}-){19})";
var re = new Regex(padrao, RegexOptions.IgnoreCase);
var matches = re.Matches(stringComHexadecimais);
foreach (Match match in matches)
     Console.WriteLine("   " + match.Value);

In this case, I made for you a regular expression with two groups: an internal one (to take the 19 values individually) and an external one, to take all the 19 values at once.

I made a Fiddle.

Notice that in Fiddle, the Group[1] is exactly what you’re looking for.

---

About reversing the String the simple way is by implementing this function (best response from here):

public static string Inverter(string s)
{
    char[] charArray = s.ToCharArray();
    Array.Reverse(charArray);
    return new string(charArray);
}

Therefore:

var grupo = match.Groups[1].ToString();
var stringInversa = Inverter(grupo);

---

Now I understand what you want. You want to locate the groups two by two, and then reverse them.

This changes the regular expression, because you need to necessarily find two groups:

var padrao = @"(13-00-00-00-(([0-9a-fA-F]{2}-){19})){2}";

Locate the larger group (matches[0].Groups[0]) and do another regular expression search on it. You will get two groups.

Just invert them and assemble another string.

Answer 2

I tried to do something that seems to be what you want. You may have problems because the problem is not well defined. If you improve the definition, I can change it a little bit and make a more organized final version. I made a version with the strokes original of the question and without the traces as it was after editing.

var texto = @"13-00-00-00-73-63-63-64-5C-73-63-63-64-5F-61-78-74-72-65-65-30-30-31-13-00-00-00-73-63-63-64-5F-61-78-74-72-65-65-30-30-31-5F-";
var divisoes = texto.Split(new[] { "13-00-00-00" }, StringSplitOptions.RemoveEmptyEntries);
foreach (var divisao in divisoes) {
    foreach (var casa in divisao.Split(new[] {'-'})) WriteLine(casa);
    WriteLine("--");
}
WriteLine("Sem traços");
texto = @"13000000736363645C736363645F61787472656530303113000000736363645F6178747265653030315F";
divisoes = texto.Split(new[] { "13000000" }, StringSplitOptions.RemoveEmptyEntries);
foreach (var divisao in divisoes) {
    for (var i = 0; i <= Min(divisao.Length - 1, 37); i+=2) WriteLine(divisao.Substring(i, 2));
    WriteLine("--");
}

Behold working in the ideone. And in the .NET Fiddle. Also put on the Github for future reference.