Move core to external libs, Starting terminal crossplatform client

OpenSaveCloudCore/Core/HashTool.cs

@@ -0,0 +1,94 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Security.Cryptography;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace OpenSaveCloudCore.Core
+{
+    internal class HashTool
+    {
+
+        /// <summary>
+        /// method <c>HashDirectory</c> walk through a directory and make a hash of all the files
+        /// </summary>
+        /// <param name="path">The path to the folder</param>
+        /// <returns>The hash of the folder</returns>
+        /// <exception cref="InvalidOperationException"></exception>
+        public static byte[]? HashDirectory(string path)
+        {
+            DirectoryInfo dir = new(path);
+            using HashAlgorithm? sha = HashAlgorithm.Create("SHA-512");
+            if (sha == null)
+            {
+                throw new InvalidOperationException("HashDirectory: SHA-512 algorithm does not exist");
+            }
+            using (var stream = new CryptoStream(Stream.Null, sha, CryptoStreamMode.Write))
+            {
+                using var writer = new BinaryWriter(stream);
+                FileSystemInfo[] infos = dir.GetFileSystemInfos();
+                Array.Sort(infos, (a, b) => string.Compare(a.Name, b.Name, StringComparison.Ordinal));
+                foreach (FileSystemInfo info in infos)
+                {
+                    writer.Write(info.Name);
+                    if ((info.Attributes & FileAttributes.Directory) == 0)
+                    {
+                        byte[]? hash = HashFile(info as FileInfo);
+                        if (hash == null)
+                        {
+                            throw new InvalidOperationException("HashDirectory: hash of the file is null");
+                        }
+                        writer.Write((byte)'F');
+                        writer.Write(hash);
+                    }
+                    else
+                    {
+                        byte[]? hash = HashDirectory(info.FullName);
+                        if (hash == null)
+                        {
+                            throw new InvalidOperationException("HashDirectory: hash of the directory is null");
+                        }
+                        writer.Write((byte)'D');
+                        writer.Write(hash);
+                    }
+                }
+            }
+            return sha.Hash;
+        }
+
+        /// <summary>
+        /// method <c>HashFile</c> make a hash SHA-512 of a file
+        /// </summary>
+        /// <param name="fileInfo">The file information</param>
+        /// <returns>The file's hash</returns>
+        /// <exception cref="Exception"></exception>
+        /// <exception cref="InvalidOperationException"></exception>
+        private static byte[]? HashFile(FileInfo? fileInfo)
+        {
+            if (fileInfo == null)
+            {
+                throw new Exception("HashFile: invalid file information");
+            }
+            using HashAlgorithm? sha = HashAlgorithm.Create("SHA-512");
+            if (sha == null)
+            {
+                throw new InvalidOperationException("HashFile: SHA-512 algorithm does not exist");
+            }
+            using var inputStream = fileInfo.OpenRead();
+            return sha.ComputeHash(inputStream);
+        }
+
+        public static string? HashFile(string path)
+        {
+            FileInfo fileInfo = new(path);
+            byte[]? hash = HashFile(fileInfo);
+            if (hash == null)
+            {
+                throw new InvalidOperationException("HashFile: file to get hash");
+            }
+            return BitConverter.ToString(hash).Replace("-", "");
+        }
+
+    }
+}