generate timestamps with meaningful accuracy

domoritz · Apr 15, 2024 · 8c86cf9 · 8c86cf9
1 parent aca95f0
commit 8c86cf9
Showing 1 changed file with 22 additions and 15 deletions.
diff --git a/js/test/generate-test-data.ts b/js/test/generate-test-data.ts
@@ -646,6 +646,7 @@ type TypedArrayConstructor =
 
 
 const rand = Math.random.bind(Math);
+const randSign = () => rand() > 0.5 ? -1 : 1;
 const randomBytes = (length: number) => fillRandom(Uint8Array, length);
 
 const memoize = (fn: () => any) => ((x?: any) => () => x || (x = fn()))();
@@ -658,15 +659,15 @@ function fillRandom<T extends TypedArrayConstructor>(ArrayType: T, length: numbe
     const BPE = ArrayType.BYTES_PER_ELEMENT;
     const array = new ArrayType(length);
     const max = (2 ** (8 * BPE)) - 1;
-    for (let i = -1; ++i < length; array[i] = rand() * max * (rand() > 0.5 ? -1 : 1));
+    for (let i = -1; ++i < length; array[i] = rand() * max * randSign());
     return array as InstanceType<T>;
 }
 
 function fillRandomBigInt<T extends (typeof BigInt64Array) | (typeof BigUint64Array)>(ArrayType: T, length: number) {
     const BPE = ArrayType.BYTES_PER_ELEMENT;
     const array = new ArrayType(length);
     const max = (2 ** (8 * BPE)) - 1;
-    for (let i = -1; ++i < length; array[i] = BigInt(rand() * max * (rand() > 0.5 ? -1 : 1)));
+    for (let i = -1; ++i < length; array[i] = BigInt(rand() * max * randSign()));
     return array as InstanceType<T>;
 }
 
@@ -732,38 +733,44 @@ function createVariableWidthBytes(length: number, nullBitmap: Uint8Array, offset
     return bytes;
 }
 
+/**
+ * Creates timestamps with the accuracy of days (86400000 millisecond).
+ */
 function createDate32(length: number, nullBitmap: Uint8Array, values: (number | null)[] = []) {
     const data = new Int32Array(length).fill(Math.trunc(Date.now() / 86400000));
     iterateBitmap(length, nullBitmap, (i, valid) => {
         if (!valid) {
             data[i] = 0;
             values[i] = null;
         } else {
-            data[i] = Math.trunc(data[i] + (rand() * 10000 * (rand() > 0.5 ? -1 : 1)));
+            data[i] = Math.trunc(data[i] + (rand() * 10000 * randSign()));
             values[i] = data[i] * 86400000;
         }
     });
     return data;
 }
 
 function createDate64(length: number, nullBitmap: Uint8Array, values: (number | null)[] = []) {
-    const data = new BigInt64Array(length).fill(0n);
     const data32 = createDate32(length, nullBitmap, values);
-    iterateBitmap(length, nullBitmap, (i, valid) => {
-        if (valid) {
-            data[i] = BigInt(data32[i] * 86400000);
-        }
-    });
-    return data;
+    return BigInt64Array.from(data32, x => BigInt(x * 86400000));
+}
+
+function divideBigInts(number: bigint, divisor: bigint): number {
+    return Number(number / divisor) + Number(number % divisor) / Number(divisor);
 }
 
 function createTimestamp(length: number, nullBitmap: Uint8Array, multiple: number, values: (number | null)[] = []) {
-    const mult = 86400 * multiple;
     const data = new BigInt64Array(length).fill(0n);
-    const data32 = createDate32(length, nullBitmap, values);
+    const tenYears = 10 * 365 * 24 * 60 * 60 * multiple;
+    const now = Math.trunc(Date.now() / 1000 * multiple);
     iterateBitmap(length, nullBitmap, (i, valid) => {
-        if (valid) {
-            data[i] = BigInt(data32[i] * mult);
+        if (!valid) {
+            data[i] = 0n;
+            values[i] = null;
+        } else {
+            const value = BigInt(now + Math.trunc(rand() * randSign() * tenYears));
+            data[i] = value;
+            values[i] = divideBigInts(value * 1000n, BigInt(multiple));
         }
     });
     return data;
@@ -776,7 +783,7 @@ function createTime32(length: number, nullBitmap: Uint8Array, multiple: number,
             data[i] = 0;
             values[i] = null;
         } else {
-            values[i] = data[i] = ((1000 * rand()) | 0 * multiple) * (rand() > 0.5 ? -1 : 1);
+            values[i] = data[i] = ((1000 * rand()) | 0 * multiple) * randSign();
         }
     });
     return data;