BigInteger Random Number Generator<\/p>\n\n\n\n
Updated: July-10,2021<\/p>\n\n\n\n
using System;\nusing System.Numerics;\nusing System.Security.Cryptography;\npublic struct RandomBigInt\n{\n private readonly RNGCryptoServiceProvider _crng;\n private int _maxByteWidth;\n private int _bitWidth;\n public RandomBigInt(int bitWidth)\n {\n MaxValue = BigIntegerHelper.GetMaxValueBitWidth(bitWidth);\n MaxValue.BitWidth = bitWidth;\n _maxByteWidth = bitWidth >> 3;\n OddsOnly = false;\n Unsigned = false;\n _crng = new RNGCryptoServiceProvider();\n _bitWidth = bitWidth;\n }\n public bool OddsOnly;\n public bool Unsigned;\n public int BitWidth\n {\n get => _bitWidth;\n set\n {\n _bitWidth = value;\n MaxValue = BigIntegerHelper.GetMaxValueBitWidth(_bitWidth);\n MaxValue.BitWidth = _bitWidth;\n _maxByteWidth = _bitWidth >> 3;\n }\n }\n public BigDecimal MaxValue;\n public bool NextBool()\n {\n return Sample() < .5;\n }\n public BigInteger Next()\n {\n return Internal();\n }\n public BigInteger Next(BigInteger minValue, BigInteger maxValue)\n {\n if (minValue > maxValue)\n throw new ArgumentException(\"maxValue must be greater than or equal to minValue\");\n return ((BigInteger)(Sample() * (maxValue - minValue)) + minValue) & (BigInteger)MaxValue;\n }\n public BigInteger Next(BigInteger maxValue)\n {\n if (maxValue < 0)\n throw new ArgumentException(\"maxValue must be greater than zero.\");\n return (BigInteger)(Sample() * maxValue) & (BigInteger)MaxValue;\n }\n public unsafe double NextDouble()\n {\n var buf = new byte[8];\n GetBytes(buf);\n fixed (byte* ptr = buf)\n {\n return *(ulong*)ptr * (1.0 \/ ulong.MaxValue) * ulong.MaxValue;\n }\n }\n public BigRational NextBigRational()\n {\n return new BigRational(Internal(), Internal());\n }\n public decimal NextDecimal()\n {\n return new decimal((int)Next(int.MaxValue), (int)Next(int.MaxValue), (int)Next(int.MaxValue), NextBool(), (byte)Next(255));\n }\n public BigDecimal NextBigDecimal()\n {\n return Sample();\n }\n public byte[] GetNextByteArray(int size)\n {\n var ba = new byte[size];\n _crng.GetBytes(ba);\n return ba;\n }\n public char[] GetNextCharArray(int size)\n {\n var xbc = new byte[1];\n var ca = new char[size];\n var ptr = 0;\n do\n {\n _crng.GetBytes(xbc);\n var c = xbc[0];\n if (c >= 0x20 && c <= 0x7F)\n ca[ptr++] = (char)c;\n } while (ptr < size);\n return ca;\n }\n public char NextChar()\n {\n var xbc = new byte[1];\n while (true)\n {\n _crng.GetBytes(xbc);\n var c = xbc[0];\n if (c >= 0x20 && c <= 0x7F)\n return (char)c;\n }\n }\n public bool[] GetNextBoolArrayLimit(int size)\n {\n var ba = new bool[size];\n const uint ll = uint.MaxValue >> 1;\n for (var i = 0; i < size; ++i)\n ba[i] = Next(0, uint.MaxValue) > ll;\n return ba;\n }\n public byte[] GetNextByteArrayLimit(int size, ulong minValue, ulong maxValue)\n {\n var ba = new byte[size];\n for (var i = 0; i < size; ++i)\n ba[i] = (byte)Next(minValue, maxValue);\n return ba;\n }\n public string GetRandomString(int Len)\n {\n return new string(GetNextCharArray(Len));\n }\n public string GetRandomString(int minLen, int maxLen)\n {\n return minLen == maxLen ? new string(GetNextCharArray(minLen)) : new string(GetNextCharArray((int)Next((uint)minLen, (uint)maxLen)));\n }\n private BigDecimal Sample()\n {\n var i = Internal();\n var s = i * (BigDecimal.One \/ MaxValue);\n if (s.IsZero)\n throw new Exception($\"Sample is zero. Check BigDecimal BitWidth {MaxValue.BitWidth} Equals BitWidth {_bitWidth}\");\n return s;\n }\n public void GetBytes(byte[] data)\n {\n if (data == null)\n throw new ArgumentException(\"The buffer cannot be null.\");\n _crng.GetBytes(data);\n }\n private BigInteger Internal()\n {\n if (Unsigned)\n {\n var buffer = new byte[_maxByteWidth + 1];\n _crng.GetBytes(buffer);\n buffer[_maxByteWidth] = 0;\n var n = new BigInteger(buffer);\n return !OddsOnly ? n : n | 1;\n }\n else\n {\n var buffer = new byte[_maxByteWidth];\n _crng.GetBytes(buffer);\n var n = new BigInteger(buffer);\n return !OddsOnly ? n : n | 1;\n }\n }\n public void NextBytes(byte[] buffer)\n {\n if (buffer == null)\n throw new ArgumentNullException(\"The buffer cannot be null.\");\n for (var index = 0; index < buffer.Length; ++index)\n buffer[index] = (byte)(Sample() * byte.MaxValue + 1);\n }\n public void GetNonZeroBytes(byte[] buffer)\n {\n if (buffer == null)\n throw new ArgumentNullException(\"The buffer cannot be null.\");\n var index = 0;\n do\n {\n var v = (byte)(Sample() * byte.MaxValue + 1);\n if (v > 0)\n {\n buffer[index] = v;\n index++;\n }\n } while (index < buffer.Length);\n }\n public string[] GetUniqueStringArray(int numberItems, int minLen, int maxLen)\n {\n var sl = new MSet15<string>();\n do\n {\n sl.Add(GetRandomString(minLen, maxLen));\n } while (sl.Count < numberItems);\n return sl.ToArray();\n }\n}<\/pre>\n","protected":false},"excerpt":{"rendered":"BigInteger Random Number Generator Updated: July-10,2021<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[2],"tags":[14,102,38,37,51],"_links":{"self":[{"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/posts\/409"}],"collection":[{"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/comments?post=409"}],"version-history":[{"count":3,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/posts\/409\/revisions"}],"predecessor-version":[{"id":484,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/posts\/409\/revisions\/484"}],"wp:attachment":[{"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/media?parent=409"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/categories?post=409"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/tags?post=409"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}