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源代码/StgSharpDebug/Math/Scalar/Random.cs

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+//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
+//     file="Random.cs"
+//     Project: StgSharp
+//     AuthorGroup: Nitload Space
+//     Copyright (c) Nitload Space. All rights reserved.
+//     
+//     Permission is hereby granted, free of charge, to any person 
+//     obtaining a copy of this software and associated documentation 
+//     files (the “Software”), to deal in the Software without restriction, 
+//     including without limitation the rights to use, copy, modify, merge,
+//     publish, distribute, sublicense, and/or sell copies of the Software, 
+//     and to permit persons to whom the Software is furnished to do so, 
+//     subject to the following conditions:
+//     
+//     The above copyright notice and 
+//     this permission notice shall be included in all copies 
+//     or substantial portions of the Software.
+//     
+//     THE SOFTWARE IS PROVIDED “AS IS”, 
+//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
+//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
+//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
+//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
+//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
+//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//     
+//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
+
+using StgSharp.Math.HighPrecession;
+
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace StgSharp.Math
+{
+    public static unsafe partial class Scaler
+    {
+
+        private static byte[] randomSeed;
+
+        /// <summary>
+        /// returns a random float number between 0 and 1.
+        /// </summary>
+        /// <returns></returns>
+        public static unsafe float LowProceisionRandom()
+        {
+            float seed = currentSeed;
+
+            float sample = Scaler.Pow(Scaler.SeedSqrt(seed), 2);
+            float sample2 = (sample - seed) / seed;
+            sample2 = Scaler.Abs(sample2);
+
+            if (sample == 1)
+            {
+                sample = sample2;
+            }
+
+            currentSeed = sample;
+            sample2 *= 1000000;
+
+            float result = sample2 - ((int)sample2);
+            if (result == 0)
+            {
+                currentSeed = sample2 + 0.1f;
+                result = Scaler.LowProceisionRandom();
+            }
+            return result;
+
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <returns></returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static T Random<T>() where T : struct, IConvertible
+#if NET8_0_OR_GREATER
+            ,INumber
+#endif
+        {
+            if (randomSeed == null)
+            {
+                randomSeed = new byte[64];
+                string originSeed =
+                    ($"{((Assembly.GetEntryAssembly() == null) ? (Assembly.GetAssembly(typeof(StgSharp))!) :
+                    Assembly.GetEntryAssembly())}") +
+                    ($"{DateTime.UtcNow.ToString("o")}");
+                using (SHA256 sha = SHA256.Create())
+                {
+                    randomSeed = sha.ComputeHash(Encoding.UTF8.GetBytes(originSeed));
+                }
+            }
+            using (SHA256 sha = SHA256.Create())
+            {
+                randomSeed = sha.ComputeHash(randomSeed);
+            }
+            fixed (byte* bptr = randomSeed)
+            {
+                return *(T*)bptr;
+            }
+        }
+
+        /// <summary>
+        /// Generates a random seed in int value.
+        /// </summary>
+        /// <returns></returns>
+        public static unsafe int RandomSeed()
+        {
+            float seedValue1 = LowProceisionRandom();
+            float seedValue2 = LowProceisionRandom();
+            uint seedValueBits = *(uint*)&seedValue1;
+
+            float seedValue = seedValueBits * seedValue2;
+
+            return *(int*)&seedValue;
+        }
+
+        internal static float currentSeed
+#if DEBUG    
+            = 0.5f;
+#else
+        = Abs(System.DateTime.UtcNow.GetHashCode());
+#endif
+
+
+    }
+}