noscrypt impl prototype and some simple tests

1 files changed, 175 insertions, 0 deletions

diff --git a/lib/NVault.Crypto.Noscrypt/src/NCUtil.cs b/lib/NVault.Crypto.Noscrypt/src/NCUtil.cs
new file mode 100644
index 0000000..61c2068
--- /dev/null
+++ b/lib/NVault.Crypto.Noscrypt/src/NCUtil.cs
@@ -0,0 +1,175 @@
+// Copyright (C) 2024 Vaughn Nugent
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+using System;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+using static NVault.Crypto.Noscrypt.LibNoscrypt;
+
+using NCResult = System.Int64;
+
+namespace NVault.Crypto.Noscrypt
+{
+    public static class NCUtil
+    {
+        /// <summary>
+        /// Gets a span of bytes from the current secret key 
+        /// structure
+        /// </summary>
+        /// <param name="key"></param>
+        /// <returns>The secret key data span</returns>
+        public unsafe static Span<byte> AsSpan(this ref NCSecretKey key)
+        {
+            //Safe to cast secret key to bytes, then we can make a span to its memory
+            ref byte asBytes = ref Unsafe.As<NCSecretKey, byte>(ref key);
+            return MemoryMarshal.CreateSpan(ref asBytes, sizeof(NCSecretKey));
+        }
+
+        /// <summary>
+        /// Gets a span of bytes from the current public key
+        /// structure
+        /// </summary>
+        /// <param name="key"></param>
+        /// <returns>The public key data as a data span</returns>
+        public unsafe static Span<byte> AsSpan(this ref NCPublicKey key)
+        {
+            //Safe to cast secret key to bytes, then we can make a span to its memory
+            ref byte asBytes = ref Unsafe.As<NCPublicKey, byte>(ref key);
+            return MemoryMarshal.CreateSpan(ref asBytes, sizeof(NCPublicKey));
+        }
+
+        /// <summary>
+        /// Casts a span of bytes to a secret key reference. Note that
+        /// the new structure reference will point to the same memory
+        /// as the span.
+        /// </summary>
+        /// <param name="span">The secret key data</param>
+        /// <returns>A mutable secret key reference</returns>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
+        public unsafe static ref NCSecretKey AsSecretKey(Span<byte> span)
+        {
+            ArgumentOutOfRangeException.ThrowIfNotEqual(span.Length, sizeof(NCSecretKey), nameof(span));
+
+            ref byte asBytes = ref MemoryMarshal.GetReference(span);
+            return ref Unsafe.As<byte, NCSecretKey>(ref asBytes);
+        }
+
+        /// <summary>
+        /// Casts a span of bytes to a public key reference. Note that
+        /// the new structure reference will point to the same memory
+        /// as the span.
+        /// </summary>
+        /// <param name="span">The public key data span</param>
+        /// <returns>A mutable reference to the public key structure</returns>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
+        public unsafe static ref NCPublicKey AsPublicKey(Span<byte> span)
+        {
+            ArgumentOutOfRangeException.ThrowIfNotEqual(span.Length, sizeof(NCPublicKey), nameof(span));
+
+            ref byte asBytes = ref MemoryMarshal.GetReference(span);
+            return ref Unsafe.As<byte, NCPublicKey>(ref asBytes);
+        }
+
+        /// <summary>
+        /// Casts a read-only span of bytes to a secret key reference. Note that
+        /// the new structure reference will point to the same memory as the span.
+        /// </summary>
+        /// <param name="span">The secret key data span</param>
+        /// <returns>A readonly refernce to the secret key structure</returns>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
+        public unsafe static ref readonly NCSecretKey AsSecretKey(ReadOnlySpan<byte> span)
+        {
+            ArgumentOutOfRangeException.ThrowIfNotEqual(span.Length, sizeof(NCSecretKey), nameof(span));
+
+            ref byte asBytes = ref MemoryMarshal.GetReference(span);
+            return ref Unsafe.As<byte, NCSecretKey>(ref asBytes);
+        }
+
+        /// <summary>
+        /// Casts a read-only span of bytes to a public key reference. Note that
+        /// the new structure reference will point to the same memory as the span.
+        /// </summary>
+        /// <param name="span">The public key data span</param>
+        /// <returns>A readonly reference to the public key structure</returns>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
+        public unsafe static ref readonly NCPublicKey AsPublicKey(ReadOnlySpan<byte> span)
+        {
+            ArgumentOutOfRangeException.ThrowIfNotEqual(span.Length, sizeof(NCPublicKey), nameof(span));
+
+            ref byte asBytes = ref MemoryMarshal.GetReference(span);
+            return ref Unsafe.As<byte, NCPublicKey>(ref asBytes);
+        }
+
+        internal static void CheckResult<T>(NCResult result) where T : Delegate
+        {
+            //Only negative values are errors
+            if (result >= NC_SUCCESS)
+            {
+                return;
+            }
+
+            NCResult asPositive = -result;
+
+            // Error code are only 8 bits, if an argument error occured, the
+            // argument number will be in the next upper 8 bits
+            byte errorCode = (byte)(asPositive & 0xFF);
+            byte argNumber = (byte)((asPositive >> 8) & 0xFF);
+
+            switch (errorCode)
+            {
+                case E_NULL_PTR:
+                    RaiseNullArgExceptionForArgumentNumber<T>(argNumber);
+                    break;
+                case E_INVALID_ARG:
+                    RaiseArgExceptionForArgumentNumber<T>(argNumber);
+                    break;
+                case E_ARGUMENT_OUT_OF_RANGE:
+                    RaiseOORExceptionForArgumentNumber<T>(argNumber);
+                    break;
+                case E_INVALID_CTX:
+                    throw new InvalidOperationException("The library context object is null or invalid");
+                case E_OPERATION_FAILED:
+                    throw new InvalidOperationException("The operation failed for an unknown reason");
+
+            }
+        }
+
+        private static void RaiseNullArgExceptionForArgumentNumber<T>(int argNumber) where T : Delegate
+        {
+            //Get delegate parameters
+            Type type = typeof(T);
+            ParameterInfo arg = type.GetMethod("Invoke")!.GetParameters()[argNumber];
+            throw new ArgumentNullException(arg.Name, "Argument is null or invalid cannot continue");
+        }
+
+        private static void RaiseArgExceptionForArgumentNumber<T>(int argNumber) where T : Delegate
+        {
+            //Get delegate parameters
+            Type type = typeof(T);
+            ParameterInfo arg = type.GetMethod("Invoke")!.GetParameters()[argNumber];
+            throw new ArgumentException("Argument is null or invalid cannot continue", arg.Name);
+        }
+
+        private static void RaiseOORExceptionForArgumentNumber<T>(int argNumber) where T : Delegate
+        {
+            //Get delegate parameters
+            Type type = typeof(T);
+            ParameterInfo arg = type.GetMethod("Invoke")!.GetParameters()[argNumber];
+            throw new ArgumentOutOfRangeException(arg.Name, "Argument is out of range of acceptable values");
+        }
+    }
+}