1 files changed, 58 insertions, 1 deletions
diff --git a/pbt/ts/src/gen.ts b/pbt/ts/src/gen.ts
index 531a118..c27cfec 100644
--- a/pbt/ts/src/gen.ts
+++ b/pbt/ts/src/gen.ts
@@ -1,4 +1,4 @@
-import {Option, none, some} from 'fp-ts/lib/Option.js';
+import { Option, none, some } from 'fp-ts/lib/Option.js';
 import Prando from 'prando';
 
 // a shrinkable generator needs to maintain some state,
@@ -71,3 +71,60 @@ export class ReplayBytes implements GenBytes {
     return chunk;
   }
 }
+
+class GenInt implements Gen<number> {
+  private bytes: BytesGen;
+
+  constructor(seed: number | undefined = undefined) {
+    this.bytes = new BytesGen(new Prando(seed ? seed : Math.random() * 1000));
+  }
+
+  generate(): number {
+    const bytes = this.bytes.generate(1);
+    return bytes[0];
+  }
+
+  generateN(n: number): number[] {
+    const result = [];
+    for (let i = 0; i < n; i++) {
+      result.push(this.bytes.generate(1)[0]);
+    }
+
+    return result;
+  }
+}
+
+class GenIntWithin implements Gen<number> {
+  private bytes: BytesGen;
+
+  constructor(private min: number, private max: number, seed: number | undefined = undefined) {
+    this.bytes = new BytesGen(new Prando(seed ? seed : Math.random() * 1000000000));
+    this.min = min;
+    this.max = max;
+  }
+
+  generate(): number {
+    const range = this.max - this.min;
+    const numBytes = Math.ceil(Math.log2(range) / 8);
+    const bytes = this.bytes.generate(numBytes);
+    let value = 0;
+    for (let i = 0; i < bytes.length; i++) {
+      value = (value << 8) | bytes[i];
+    }
+    return this.min + (value % range);
+  }
+
+  generateN(n: number): number[] {
+    const result = [];
+    for (let i = 0; i < n; i++) {
+      result.push(this.bytes.generate(1)[0]);
+    }
+
+    return result;
+  }
+
+}
+
+export const genInt = (seed : number | undefined = undefined) => new GenInt(seed);
+
+export const genIntWithin = (min: number, max: number, seed : number | undefined = undefined) => new GenIntWithin(min, max, seed);