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moved SeedSource to its own file and added Rotate
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2 changed files with 105 additions and 95 deletions
104
MLEM/Misc/SeedSource.cs
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104
MLEM/Misc/SeedSource.cs
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using System;
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namespace MLEM.Misc {
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/// <summary>
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/// A seed source contains an <see cref="int"/> value which can be used as a seed for a <see cref="System.Random"/> or <see cref="SingleRandom"/>. Seed sources feature a convenient way to add multiple seeds using <see cref="Add(int)"/>, which will be sufficiently scrambled to be deterministically pseudorandom and combined into a single <see cref="int"/>.
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/// This struct behaves similarly to <c>System.HashCode</c> in many ways, with an important distinction being that <see cref="SeedSource"/>'s scrambling procedure is not considered an implementation detail, and will stay consistent between process executions.
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/// </summary>
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/// <example>
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/// For example, a seed source can be used to create a new <see cref="System.Random"/> based on an object's <c>x</c> and <c>y</c> coordinates by combining them into a <see cref="SeedSource"/> using <see cref="Add(int)"/>. The values generated by the <see cref="System.Random"/> created using <see cref="Random()"/> will then be determined by the specific pair of <c>x</c> and <c>y</c> values used.
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/// </example>
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public readonly struct SeedSource {
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private readonly int? value;
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/// <summary>
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/// Creates a new seed source from the given seed, which will be added automatically using <see cref="Add(int)"/>.
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/// </summary>
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/// <param name="seed">The initial seed to use.</param>
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public SeedSource(int seed) : this() {
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this = this.Add(seed);
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}
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/// <summary>
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/// Creates a new seed source from the given set of seeds, which will be added automatically using <see cref="Add(int)"/>.
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/// </summary>
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/// <param name="seeds">The initial seeds to use.</param>
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public SeedSource(params int[] seeds) : this() {
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foreach (var seed in seeds)
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this = this.Add(seed);
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}
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private SeedSource(int? value) {
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this.value = value;
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}
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/// <summary>
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/// Adds the given seed to this seed source's value and returns the result as a new seed source.
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/// The algorithm used for adding involves various scrambling operations that sufficiently pseudo-randomize the seed and final value.
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/// </summary>
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/// <param name="seed">The seed to add.</param>
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/// <returns>A new seed source with the seed added.</returns>
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public SeedSource Add(int seed) {
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return new SeedSource(new int?(SeedSource.Scramble(this.Get()) + SeedSource.Scramble(seed)));
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}
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/// <summary>
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/// Adds the given seed to this seed source's value and returns the result as a new seed source.
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/// Floating point values are scrambled by invoking <see cref="Add(int)"/> using a typecast version, followed by invoking <see cref="Add(int)"/> using the decimal value multiplied by <see cref="int.MaxValue"/>.
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/// </summary>
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/// <param name="seed">The seed to add.</param>
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/// <returns>A new seed source with the seed added.</returns>
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public SeedSource Add(float seed) {
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return this.Add((int) seed).Add((seed - (int) seed) * int.MaxValue);
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}
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/// <summary>
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/// Adds the given seed to this seed source's value and returns the result as a new seed source.
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/// Strings are scrambled by invoking <see cref="Add(int)"/> using every character contained in the string, in order.
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/// </summary>
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/// <param name="seed">The seed to add.</param>
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/// <returns>A new seed source with the seed added.</returns>
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public SeedSource Add(string seed) {
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var ret = this;
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foreach (var c in seed)
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ret = ret.Add(c);
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return ret;
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}
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/// <summary>
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/// Returns a new seed source whose value is this seed source's value, but scrambled further.
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/// In essence, this creates a new seed source whose value is determined by the current seed source.
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/// </summary>
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/// <returns>A new seed source with a rotated value.</returns>
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public SeedSource Rotate() {
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return new SeedSource(new int?(SeedSource.Scramble(this.Get())));
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}
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/// <summary>
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/// Returns this seed source's seed value, which can then be used in <see cref="SingleRandom"/> or elsewhere.
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/// </summary>
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/// <returns>This seed source's value.</returns>
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public int Get() {
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return this.value ?? 1623487;
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}
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/// <summary>
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/// Returns a new <see cref="Random"/> instance using this source seed's value, retrieved using <see cref="Get"/>.
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/// </summary>
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/// <returns>A new <see cref="Random"/> using this seed source's value.</returns>
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public Random Random() {
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return new Random(this.Get());
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}
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private static int Scramble(int x) {
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x += 84317;
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x ^= x << 7;
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x *= 207398809;
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x ^= x << 17;
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x *= 928511849;
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return x;
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}
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}
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}
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@ -1,6 +1,4 @@
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using System;
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namespace MLEM.Misc {
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namespace MLEM.Misc {
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/// <summary>
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/// The SingleRandom class allows generating single, one-off pseudorandom numbers based on a seed or a <see cref="SeedSource"/>.
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/// The types of numbers that can be generated are <see cref="int"/> and <see cref="float"/>, both of which can be generated with specific minimum and maximum values if desired.
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@ -141,96 +139,4 @@ namespace MLEM.Misc {
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}
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}
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/// <summary>
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/// A seed source contains an <see cref="int"/> value which can be used as a seed for a <see cref="System.Random"/> or <see cref="SingleRandom"/>. Seed sources feature a convenient way to add multiple seeds using <see cref="Add(int)"/>, which will be sufficiently scrambled to be deterministically semi-random and combined into a single <see cref="int"/>.
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/// This struct behaves similarly to <c>System.HashCode</c> in many ways, with an important distinction being that <see cref="SeedSource"/>'s scrambling procedure is not considered an implementation detail, and will stay consistent between process executions.
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/// </summary>
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/// <example>
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/// For example, a seed source can be used to create a new <see cref="System.Random"/> based on an object's <c>x</c> and <c>y</c> coordinates by combining them into a <see cref="SeedSource"/> using <see cref="Add(int)"/>. The values generated by the <see cref="System.Random"/> created using <see cref="Random()"/> will then be determined by the specific pair of <c>x</c> and <c>y</c> values used.
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/// </example>
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public readonly struct SeedSource {
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private readonly int? value;
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/// <summary>
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/// Creates a new seed source from the given seed, which will be added automatically using <see cref="Add(int)"/>.
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/// </summary>
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/// <param name="seed">The initial seed to use.</param>
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public SeedSource(int seed) : this() {
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this = this.Add(seed);
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}
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/// <summary>
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/// Creates a new seed source from the given set of seeds, which will be added automatically using <see cref="Add(int)"/>.
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/// </summary>
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/// <param name="seeds">The initial seeds to use.</param>
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public SeedSource(params int[] seeds) : this() {
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foreach (var seed in seeds)
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this = this.Add(seed);
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}
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private SeedSource(int? value) {
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this.value = value;
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}
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/// <summary>
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/// Adds the given seed to this seed source's value and returns the result as a new seed source.
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/// The algorithm used for adding involves various scrambling operations that sufficiently semi-randomize the seed and final value.
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/// </summary>
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/// <param name="seed">The seed to add.</param>
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/// <returns>A new seed source with the seed added.</returns>
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public SeedSource Add(int seed) {
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return new SeedSource(new int?(SeedSource.Scramble(this.Get()) + SeedSource.Scramble(seed)));
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}
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/// <summary>
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/// Adds the given seed to this seed source's value and returns the result as a new seed source.
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/// Floating point values are scrambled by invoking <see cref="Add(int)"/> using a typecast version, followed by invoking <see cref="Add(int)"/> using the decimal value multiplied by <see cref="int.MaxValue"/>.
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/// </summary>
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/// <param name="seed">The seed to add.</param>
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/// <returns>A new seed source with the seed added.</returns>
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public SeedSource Add(float seed) {
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return this.Add((int) seed).Add((seed - (int) seed) * int.MaxValue);
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}
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/// <summary>
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/// Adds the given seed to this seed source's value and returns the result as a new seed source.
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/// Strings are scrambled by invoking <see cref="Add(int)"/> using every character contained in the string, in order.
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/// </summary>
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/// <param name="seed">The seed to add.</param>
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/// <returns>A new seed source with the seed added.</returns>
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public SeedSource Add(string seed) {
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var ret = this;
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foreach (var c in seed)
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ret = ret.Add(c);
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return ret;
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}
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/// <summary>
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/// Returns this seed source's seed value, which can then be used in <see cref="SingleRandom"/> or elsewhere.
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/// </summary>
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/// <returns>This seed source's value.</returns>
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public int Get() {
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return this.value ?? 1623487;
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}
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/// <summary>
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/// Returns a new <see cref="Random"/> instance using this source seed's value, retrieved using <see cref="Get"/>.
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/// </summary>
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/// <returns>A new <see cref="Random"/> using this seed source's value.</returns>
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public Random Random() {
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return new Random(this.Get());
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}
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private static int Scramble(int x) {
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x += 84317;
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x ^= x << 7;
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x *= 207398809;
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x ^= x << 17;
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x *= 928511849;
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return x;
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}
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}
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}
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