feat(random): add IRandom.minmaxUint()

- clarify .minmaxInt() is for signed (i32) - new .minmaxUint() is for unsigned (u32) - add ARandom.minmaxUint()
thi-ng · Aug 11, 2023 · 6558eb1 · 6558eb1
1 parent 770dbe5
commit 6558eb1
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Showing 3 changed files with 18 additions and 4 deletions.
diff --git a/packages/random/src/api.ts b/packages/random/src/api.ts
@@ -55,7 +55,7 @@ export interface IRandom extends INorm {
 	 */
 	minmax(min: number, max: number): number;
 	/**
-	 * Returns int in [min..max) interval.
+	 * Returns int in **signed** integer [min..max) interval.
 	 *
 	 * @remarks
 	 * See: https://github.com/thi-ng/umbrella/wiki/Glossary#interval
@@ -64,6 +64,16 @@ export interface IRandom extends INorm {
 	 * @param max -
 	 */
 	minmaxInt(min: number, max: number): number;
+	/**
+	 * Returns int in **unsigned** integer [min..max) interval.
+	 *
+	 * @remarks
+	 * See: https://github.com/thi-ng/umbrella/wiki/Glossary#interval
+	 *
+	 * @param min -
+	 * @param max -
+	 */
+	minmaxUint(min: number, max: number): number;
 }
 
 export interface ISeedable<T> {

diff --git a/packages/random/src/arandom.ts b/packages/random/src/arandom.ts
@@ -24,7 +24,11 @@ export abstract class ARandom implements IRandom {
 
 	minmaxInt(min: number, max: number) {
 		min |= 0;
-		max |= 0;
-		return min + ((this.float() * (max - min)) | 0);
+		return min + (this.int() % ((max | 0) - min));
+	}
+
+	minmaxUint(min: number, max: number) {
+		min >>>= 0;
+		return min + (this.int() % ((max >>> 0) - min));
 	}
 }
diff --git a/packages/random/src/system.ts b/packages/random/src/system.ts
@@ -8,7 +8,7 @@ const random = Math.random;
  */
 export class SystemRandom extends ARandom {
 	int() {
-		return (random() * 4294967296) /* 2**32 */ >>> 0;
+		return (random() * 0x1_0000_0000) /* 2**32 */ >>> 0;
 	}
 
 	float(norm = 1) {